JP2002115687A - Cooling structure in vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the durability of a contact type seal means for a shaft seal preventing the entry of oil into a pump chamber in a vacuum pump. SOLUTION: A part of lubricating oil Y scraped up from a bottom part of a gear storage chamber 331 by the rotation of gears 34, 35 enters remaining spaces 143, 144 from slits 47, 49. The lubricating oil Y entering the remaining spaces 143, 144 lubricates lip seals 44, 45 and cools the lip seal 44 and its peripheral member. The lubricating oil Y lubricating the lip seals 44, 45 and cooling the lip seal 44 and its peripheral member is refluxed in a bottom part of the gear storage chamber 331 through slits 48, 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure in a vacuum pump which moves a gas transfer member in a pump chamber based on rotation of a rotary shaft and transfers a gas by the operation of the gas transfer member to provide a suction effect. It is.

[0002]

2. Description of the Related Art A vacuum pump disclosed in Japanese Patent Application Laid-Open No. 2-157490 and Japanese Patent Application Laid-Open No.
The rotor is rotated in a state where two adjacent rotors are engaged with each other. The rotating operation of the two rotors rotating while meshing transfers gas. One of the rotation axes of the rotor is
The driving force is obtained from the motor, and the other rotating shaft receives the driving force from the one rotating shaft via a gear mechanism.

[0003] Lubricating oil is stored in a housing that houses the gear mechanism, and the stored oil lubricates the gear mechanism. In order to prevent the lubricating oil from leaking into the pump chamber, a lip seal is provided between a housing part of the rotary shaft and a housing part penetrating a housing wall separating the housing chamber of the gear mechanism and the pump chamber. .

[0004]

The lip seal deteriorates when exposed to a high-temperature environment, and the sealing function of the lip seal deteriorates. A radial bearing for rotatably supporting the rotating shaft is provided in front of the lip seal, and the above-described lubricating oil is also used for lubrication of the radial bearing. The aforementioned lubricating oil for lubricating the gear mechanism and the radial bearing is:
Although it can be used for cooling the lip seal, it does not have an oil passage configuration that sends lubricating oil to the position of the lip seal deeper than the radial bearing and recirculates it. Therefore, the lip seal cannot be cooled efficiently,
The life of the lip seal is shortened.

[0005] It is an object of the present invention to improve the durability of a contact-type sealing means for a shaft seal for preventing oil from entering a pump chamber of a vacuum pump.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a vacuum pump which moves a gas transfer body in a pump chamber based on rotation of a rotating shaft and transfers gas by the operation of the gas transfer body to provide a suction action. According to the invention of claim 1, the oil-existing region and the pump chamber are adjacent to each other, and a partition that penetrates the rotary shaft and a periphery of the rotary shaft that penetrates the partition and protrudes into the oil-existing region. A contact-type sealing means for sealing a shaft disposed between a surface and a through-hole of the partition through which the rotary shaft passes; and supplying oil from the oil-existing region to a storage space for storing the contact-type sealing means. A cooling structure including an oil passage for returning oil supplied to the storage space to an oil existing area, and an oil scooping unit for scavenging oil stored in the oil existing area; Above the entrance A wall is provided, the inlet is provided above the rotary shaft, and at least a part of an outlet of the oil passage is provided below a height position of the rotary shaft. Oil is supplied from the inlet of the passage into the oil passage.

[0007] A part of the oil pumped up by the oil pumping means enters the oil passage from the inlet of the oil passage above the rotary shaft. The oil that has entered the oil passage cools the contact-type sealing means and returns to the oil existing area. The configuration in which the oil is recirculated to the oil existing area via the housing space of the contact-type sealing means efficiently cools the contact-type sealing means.

[0008] In the invention of claim 2, in claim 1,
The oil passage extends along the entire circumference of the rotating shaft adjacent to the entire circumference of the housing space. The accommodation space for accommodating the contact-type sealing means has an annular shape surrounding the rotation shaft, and the entire circumference of the rotation shaft near the annular accommodation space is in an oil passage adjacent to the entire circumference of the annular accommodation space. Cooled by oil. The configuration in which the entire circumference of the rotating shaft near the annular accommodation space is cooled with oil contributes to an improvement in cooling efficiency of the contact-type sealing means.

According to the third aspect of the present invention, in the second aspect,
At least a part of the outlet of the oil passage is provided in the partition, and the outlet provided in the partition is provided below the rotary shaft.

The oil that has cooled the entire circumference of the rotary shaft near the annular storage space returns to the oil-existing region from the outlet below the rotary shaft. According to a fourth aspect of the present invention, in any one of the first to third aspects, a bearing for rotatably supporting the rotating shaft is interposed between the partition and the rotating shaft, and The sealing means is located closer to the pump chamber than the bearing.

[0011] The contact-type sealing means located deeper than the bearing is cooled by oil flowing through the oil passage. According to the fifth aspect of the present invention, in the fourth aspect, the bearing is a radial bearing, and a gap between an outer ring and an inner ring of the radial bearing is a part of the oil passage and located downstream of the housing space. I did it.

The oil supplied to the housing space and cooling the contact-type sealing means lubricates the radial bearing. In the invention of claim 6, in claim 5, the outlet of the oil passage is only the gap between the outer ring and the inner ring of the radial bearing.

All of the oil supplied to the housing space and cooling the contact-type sealing means passes through the gap of the radial bearing. According to a seventh aspect of the present invention, in any one of the first to sixth aspects, an oil reservoir is provided upstream of the outlet so as to communicate with the oil passage and below the outlet.

The oil reservoir improves the lubrication of oil in the storage space. According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the contact-type sealing means comprises:
A rubber lip seal for preventing oil in the oil existing area from leaking to the pump chamber side along the peripheral surface of the rotating shaft.

A lip seal made of rubber is a contact-type sealing means having high sealing performance. In a ninth aspect of the present invention, in any one of the first to eighth aspects, the vacuum pump arranges a plurality of the rotating shafts in parallel, and arranges a rotor on each of the rotating shafts, and arranges A vacuum pump having a plurality of pump chambers or a single pump chamber accommodating a plurality of rotors meshing with each other on a rotating shaft that meshes with each other and accommodating a plurality of rotors engaged with each other as a set. The oil-existing region is a region for accommodating the gear mechanism, and the oil scraping means is the gear mechanism.

The gear mechanism is simple as an oil scraping means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in a roots pump will be described below with reference to FIGS.

As shown in FIG. 1, the multi-stage roots pump 11
The front housing 13 is joined to the front end of the rotor housing 12 of the first embodiment, and the closing body 36 is joined to the front housing 13. A rear housing 14 as a partition is joined to the rear end of the rotor housing 12. The rotor housing 12 includes a cylinder block 15 and a plurality of chamber forming walls 16. As shown in FIG. 3B, the cylinder block 15 includes a pair of block pieces 17,
18, the chamber forming wall 16 is formed of a pair of wall pieces 161, 16
Consists of two. As shown in FIG.
The space between the chamber forming wall 3 and the room forming wall 16, the space between the adjacent room forming walls 16, and the space between the rear housing 14 and the room forming wall 16 are pump chambers 39, 40, 41, and 4, respectively.
2,43.

A pair of rotating shafts 19, 20 are rotatably supported by the front housing 13 and the rear housing 14 via radial bearings 21, 37, 22, 38 as bearings. Both rotating shafts 19 and 20 are arranged parallel to each other. The rotation shafts 19 and 20 are passed through the chamber forming wall 16.

A plurality of rotors 23, 24, 25, 26, 27 as a gas transfer member are integrally formed on the rotating shaft 19, and the same number of rotors 28, 29, 30, are formed on the rotating shaft 20.
31 and 32 are integrally formed. Rotors 23-32
Have the same shape and the same size when viewed in the directions of the axes 191 and 201 of the rotating shafts 19 and 20. Rotors 23, 24, 2
The thicknesses of the rotors 5, 26, 27 decrease in this order, and the thicknesses of the rotors 28, 29, 30, 31, 32 also decrease in this order.
The rotors 23 and 28 are housed in the pump chamber 39 in a state of being engaged with each other with a slight gap therebetween.
Similarly, the pumps 9 are housed in the pump chamber 40 in a mutually engaged state. Similarly, the rotors 25 and 30 are in the pump chamber 41, the rotors 26 and 31 are in the pump chamber 42,
7, 32 are housed in the pump chamber 43, respectively.

The gear housing 3 is mounted on the rear housing 14.
3 are joined. The rotating shafts 19 and 20 pass through the rear housing 14 and protrude into the gear housing 33. The protruding ends 192 and 202 of the rotating shafts 19 and 20 are fixed to the gears 34 and 35 in a state where the gears 34 and 35 mesh with each other. Have been. An electric motor M is mounted on the gear housing 33. The driving force of the electric motor M is transmitted to the rotating shaft 19 via the shaft joint 10, and the rotating shaft 19 is rotated by the electric motor M in the direction of arrow R <b> 1 in FIGS. 3A, 3 </ b> B, and 3 </ b> C. Is done. The rotating shaft 20 obtains a driving force from the electric motor M via gears 34 and 35, and the rotating shaft 20 is rotated by the rotating shaft 19 as shown by an arrow R2 in FIGS. 3 (a), 3 (b) and 3 (c). And rotate in the opposite direction.

As shown in FIG. 4A, the gears 34, 35
The lubricating oil Y is stored at the bottom of the gear housing chamber 331 that houses the gear mechanism composed of. The lubricating oil Y is
It is picked up by the rotation operation of 35. Gears 34,3
The gear mechanism composed of 5 serves as oil scraping means for scraping the stored oil. The lubricating oil Y lubricates the gears 34, 35 and the radial bearings 37, 38. The rear housing 14 serves as a partition wall that separates the pump chamber 43 from the gear housing chamber 331 which is an oil existing area.

As shown in FIG. 3B, a passage 163 is formed in the chamber forming wall 16. An inlet 164 and an outlet 165 of the passage 163 are formed in the chamber forming wall 16. The adjacent pump chambers 39, 40, 41, 42, 43
They communicate with each other via a passage 163.

As shown in FIG. 3A, the block piece 18
Is formed such that an inlet 181 communicates with the pump chamber 39. As shown in FIG.
Is formed so that a discharge port 171 communicates with the pump chamber 43. The gas introduced into the pump chamber 39 from the inlet 181 is rotated by the rotation of the rotors 23 and 28 to form the chamber forming wall 1.
6 from the inlet 164 via the passage 163 to the adjacent pump chamber 40 from the outlet 165. Hereinafter, similarly, the gas flows in the order of decreasing the volume of the pump chamber, that is, the pump chamber 4
They are transferred in the order of 0, 41, 42, 43. Pump room 43
The gas transferred to the discharge port is discharged from the discharge port 171 to the outside. The rotors 23 to 32 are gas transfer bodies that transfer gas.

As shown in FIG. 1, the radial bearing 3
7 and 38 are accommodated in fitting chambers 141 and 142 formed on the end surface of the rear housing 14 forming the gear housing chamber 331. Remaining spaces 143 and 144 are left between the bottoms of the fitting chambers 141 and 142 and the radial bearings 37 and 38. The remaining spaces 143 and 144 constitute a part of an oil passage described later. Housing chambers 145 and 146 are further formed at the bottoms of the fitting chambers 141 and 142 so as to surround the rotating shafts 19 and 20. The accommodation chambers 145 and 146 serving as the accommodation space are provided on the rear housing 14 with the rotating shaft 1.
It is recessed in the peripheral wall surface of the through holes 60 and 61 through which the holes 9 and 20 pass. Rubber lip seals 44 and 45 are accommodated in the accommodation chambers 145 and 146, respectively. Lip seal 4
4 and 45 provide a sealing effect by slidingly contacting the peripheral surfaces of the protruding ends 192 and 202 which are the protruding portions of the rotating shafts 19 and 20.

As shown in FIGS. 4 (a), 4 (b) and 4 (c), an annular groove 46 is provided on the end surface of the rear housing 14 forming the gear housing chamber 331 as the oil existing area.
0 is formed. On the end face of the rear housing 14 with respect to the rotation shaft 19, slits 47 and 48 which become a part of an oil passage are formed with the annular groove 46 and the remaining space 143.
It is formed so that it may communicate with. The slit 47 is located directly above the rotation axis 19, and the slit 48 is located immediately below the rotation axis 19. The slits 49 and 50 which also form part of the oil passage are formed in the end surface of the rear housing 14 with respect to the rotation shaft 20.
Are formed so as to communicate with the annular groove 46 and the remaining space 144. The slit 49 is located immediately above the rotation shaft 20,
The slit 50 is directly below the rotation shaft 20.

A portion of the lubricating oil Y that has been lifted from the bottom of the gear housing chamber 331 by the rotation of the gears 34 and 35 enters the annular groove 46 and enters the remaining space 143 from the slit 47. The lubricating oil Y that has entered the remaining space 143 lubricates the lip seal 44 and cools the lip seal 44 and its peripheral members. The lubricating oil Y that has lubricated the lip seal 44 and cooled the lip seal 44 and its peripheral members is supplied to the slit 48 or the inner ring 371 of the radial bearing 37 as shown by arrows P1 and P2 in FIG.
Through the gap 373 between the gear housing chamber 33 and the outer ring 372.
Reflux to the bottom of 1. Slit 47, residual space 143,
The slit 48 and the gap 373 constitute an oil passage L1 (not shown) for cooling the lip seal 44. The slit 47 serves as an inlet of the oil passage L1, and the slit 48
The gap 373 serves as an outlet of the oil passage L1.

A portion of the lubricating oil Y that has been lifted up from the bottom of the gear housing chamber 331 by the rotation of the gears 34 and 35 enters the remaining space 144 from the slit 49 in the same manner. The lubricating oil Y that has entered the remaining space 144 lubricates the lip seal 45 and cools the lip seal 45 and its peripheral members. The lubricating oil Y that has lubricated the lip seal 45 and cooled the lip seal 45 and its peripheral members is supplied to the slit 50 or the inner ring 381 and the outer ring 38 of the radial bearing 38 as shown by arrows Q1 and Q2 in FIG.
The fluid flows back to the bottom of the gear housing chamber 331 through the gap 383 between the gear housing chamber 331 and the gear housing chamber 331. Slit 49, residual space 144, slit 5
The zero and the gap 383 constitute an oil passage L2 (not shown) for cooling the lip seal 45. Slit 49
Is the entrance of the oil passage L2, and the slit 50 and the gap 3
83 is an outlet of the oil passage L2.

A cooler 51 is mounted on the outer surface of the bottom wall 332 of the gear housing 33. A supply pipe 511 and a discharge pipe 512 are connected to the cooler 51. The supply pipe 511 sends a coolant from a coolant supply source (not shown) to the cooler 51, and the discharge pipe 512 returns the coolant passing through the cooler 51 to the coolant supply source. The cooling liquid passing through the inside of the cooler 51 cools the bottom wall 332 of the gear housing 33 in contact with the surface of the cooler 51, and the cooler 51 indirectly transfers the lubricating oil Y accumulated at the bottom of the gear housing chamber 331. Cool down.

In the first embodiment, the following effects can be obtained. (1-1) The diameter of the gears 34 and 35 is
Since the diameter of the lubricating oil Y is larger than the diameters of the radial bearings 37 and 38, the lubricating oil Y is removed from the gaps 373 and 383 of the radial bearings 37 and 38.
It is difficult to enter 144 directly. Also, the remaining space 14
3,144, the lubricating oil Y enters the remaining space 143,1
It takes time to recirculate from 44 to the gear storage chamber 331. That is, the gap 37 between the radial bearings 37 and 38
When the lubricating oil Y enters and leaves the remaining spaces 143 and 144 via the third space 383, the remaining space 14
The replacement of the lubricating oil Y in 3,144 is not performed smoothly, and the cooling efficiency of the lip seals 44, 45 located deeper than the radial bearings 37, 38 becomes very poor.

In the first embodiment, the lip seals 44 and 45, which are contact-type sealing means, are connected to the oil passages L1 and L1, respectively.
It is directly cooled by the lubricating oil Y flowing through L2. The oil passages L1, L2 extend downward from above the rotating shafts 19, 20 and have slits 47, which are inlets of the oil passages L1, L2.
49 is formed in the rear housing 14 which is a partition. Slits 47 and 49 which are inlets of the oil passages L1 and L2
Are located above the radial bearings 37 and 38 as bearings. Therefore, the lubricating oil Y that has entered the oil passages L1 and L2 smoothly returns to the bottom of the gear housing chamber 331.
Such smooth circulation of the lubricating oil Y results in efficient cooling of the lip seals 44 and 45, which are contact-type sealing means for the shaft seal, and extends the life of the lip seals 44 and 45.

(1-2) The storage chambers 145 and 146, which are the storage spaces for storing the lip seals 44 and 45,
The annular shape surrounding the oil passages 9 and 20 and the oil passages L1 and L2
Are adjacent to each other so as to communicate with the annular storage chambers 145 and 146. The entire circumference of the rotating shafts 19 and 20 near the annular storage chambers 145 and 146 is cooled by the lubricating oil Y flowing through the remaining spaces 143 and 144. Rotation axis 1 near accommodation chambers 145 and 146
The configuration in which the entire circumferences of the nip seals 9 and 20 are cooled with the lubricating oil Y contributes to an improvement in the efficiency of cooling the lip seals 44 and 45.

(1-3) The gaps 373 and 383 between the radial bearings 37 and 38 are part of the oil passages L1 and L2 and are downstream from the storage chambers 145 and 146. Containment room 14
A portion of the lubricating oil Y that has cooled the lip seals 44 and 45 in the radial bearings 37 and 38
73, 383 and radial bearings 37, 38
To lubricate. The configuration in which the radial bearings 37, 38 are lubricated by the lubricating oil Y flowing through the oil passages L1, L2 sufficiently lubricates the radial bearings 37, 38, and extends the life of the radial bearings 37, 38.

(1-4) Lubricating oil Y in gear housing 33
Accumulates on the bottom of the gear storage chamber 331, that is, on the inner surface of the bottom wall 332. The heat of the lubricating oil Y accumulated on the inner surface of the bottom wall 332 is transmitted to the cooler 51 via the bottom wall 332. Therefore, the configuration in which the bottom wall 332 that is in contact with the stored oil is covered with the cooler 51 is optimal for improving the efficiency of cooling the lubricating oil Y that has cooled the lip seals 44 and 45.

(1-5) Lip seals 44 and 45 made of rubber
Is very excellent in close contact with the peripheral surfaces of the rotating shafts 19 and 20, but the durability is extremely reduced without lubrication with the lubricating oil Y. The rubber lip seals 44 and 45 that are lubricated by the lubricating oil Y and receive a cooling action are contact-type sealing means that can ensure high durability and high sealing performance.

(1-6) The pump chamber 43 is a pump chamber having a minimum volume adjacent to the gear housing chamber 331 via the rear housing 14 serving as a partition. The pump chamber 43 having the minimum volume is a place where the temperature is the highest. Therefore, the rear housing 1
The temperatures of the protruding ends 192 and 202 of the rotary shaft 4 and the rotating shafts 19 and 20 are also likely to be high, and the lip seals 44 and 45 are exposed to a severe high temperature environment. Therefore, the lip seals 44, 4
5 is extremely important, and the present invention is particularly suitable for application to the multi-stage roots pump 11 having the lip seals 44 and 45, which are important cooling targets.

Next, a second embodiment shown in FIGS. 5 to 8 will be described. The same components as those in the first embodiment are denoted by the same reference numerals. In this embodiment, instead of the slits 48 and 50 in the first embodiment, storage recesses 52 and 53 as oil storage portions are recessed at the bottoms of the remaining spaces 143 and 144. The storage recesses 52 and 53 are located at positions lower than the gaps 373 and 383 between the radial bearings 37 and 38, and a part of the lubricating oil Y flowing through the remaining spaces 143 and 144 is stored in the storage recesses 52 and 53.

The lubricating oil Y, which lubricates the lip seal 44 and cools the lip seal 44 and its peripheral members,
As shown by an arrow P3 in FIG. 5A, the fluid flows back to the bottom of the gear housing chamber 331 via a gap 373 between the inner ring 371 and the outer ring 372 of the radial bearing 37. Slit 47,
The remaining space 143 and the gap 373 constitute an oil passage L3 (not shown) for cooling the lip seal 44.
The gap 373 serves as an outlet of the oil passage L3.

Similarly, the lubricating oil Y which has lubricated the lip seal 45 and cooled the lip seal 45 and its peripheral members is supplied to the inner ring 381 and the outer ring 382 of the radial bearing 38 as shown by an arrow Q3 in FIG. Gap 38 with
The fluid is returned to the bottom of the gear housing chamber 331 via 3. The slit 49, the remaining space 144, and the gap 383 constitute an oil passage L4 (not shown) for cooling the lip seal 45. The gap 383 serves as an outlet of the oil passage L4.

The following effects are obtained in the second embodiment. (2-1) The same effect as in the first embodiment can be obtained. (2-2) Part of the lubricating oil Y scraped up by the rotation of the gears 34, 35 enters the oil passages L3, L4 and returns to the bottom of the gear housing chamber 331. The presence of 52 and 53 results in a stagnation of the flow of the lubricating oil Y in the remaining spaces 143 and 144, that is, a semi-stationary state where the lubricating oil Y does not flow much. Therefore, the accommodation chambers 145, 14
6, the oil lubricity is improved, and the lip seals 44, 45
Is more efficiently performed than in the case of the first embodiment.

A curve E in the graph of FIG. 8 represents the relationship between the amount of the lubricating oil Y in the gear housing 33 and the temperatures of the lip seals 44 and 45 in the second embodiment. A curve D represents the amount of the lubricating oil Y in the gear housing 33 in the first embodiment,
45 represents the relationship with the temperature. If the amount of the lubricating oil Y in the gear housing 33 is increased, the cooling efficiency of the lip seals 44 and 45 is improved. In the second embodiment in which the storage recesses 52 and 53 are provided, the lip seals 44 and 45 can be effectively cooled with a smaller amount of oil than in the first embodiment.

(2-3) Lubricating oil Y in gear housing 33
The smaller the amount of the oil, the lower the oil level of the stored oil at the bottom of the gear housing chamber 331, and the lower the resistance in raising the oil when the gears 34 and 35 rotate. Reduction of the scraping resistance results in reduced power consumption of the vacuum pump. The roots pump of the second embodiment, which can reduce the amount of oil as compared with the first embodiment, can effectively make the lip seals 44, 45 with less power consumption than the vacuum pump of the first embodiment. Can be cooled.

(2-4) When the lubricating oil Y is stored in the storage recesses 52 and 53, the amount of oil stored at the bottom of the gear housing chamber 331 is reduced. This state also reduces the scraping resistance at the time of scraping the oil by the rotation of the gears 34 and 35.

Next, a third embodiment shown in FIGS. 9A and 9B will be described. The same components as those in the second embodiment are denoted by the same reference numerals. In this embodiment, there are no storage recesses 52 and 53 in the second embodiment. However, the outlet of the oil passage L3 is only the gap 373, 383 between the radial bearings 37, 38, and the remaining spaces 143, 144
The lubricating oil Y accumulates at the bottom. That is, portions of the remaining spaces 143 and 144 below the lowest positions S1 and S2 on the inner circumference of the outer rings 372 and 382 of the radial bearings 37 and 38 serve as storage recesses.

Next, a fourth embodiment shown in FIGS. 10 to 12 will be described. The same components as those in the second embodiment are denoted by the same reference numerals. Cylindrical bearing holders 54 and 55 are fitted in the fitting chambers 141 and 142, and radial bearings 37 and 38 are fitted in the bearing holders 54 and 55.
Outer rings 372 and 382 are fitted and fixed. Flanges 541 and 551 are formed on the bearing holders 54 and 55, and the flanges 541 and 551 are joined to end faces of the rear housing 14 via spacers 56 and 57. The bearing holders 54 and 55 are
41, 551 and screws 5 passed through spacers 56, 57
It is fixed to the rear housing 14 by tightening 8,59.

The radial bearings 37, 38 are attached to the rotating shafts 19, 20 so as not to move in the directions of the axes 191, 201. The positions of the rotation shafts 19 and 20 in the directions of the axes 191 and 201 with respect to the rear housing 14 can be adjusted by changing the number of spacers 56 and 57. That is, the positions of the rotors 23 to 32 with respect to the pump chambers 39 to 43 in the directions of the axes 191, 201 are
It can be adjusted by changing the number of spacers 56 and 57. Such adjustment is important in performing clearance adjustment between the rotors 23 to 32, the chamber forming wall 16, which is the forming wall of the pump chambers 39 to 43, the front housing 13, and the rear housing 14.

In this embodiment, the lowermost position S on the inner circumference of the outer rings 372, 382 of the radial bearings 37, 38
The bottoms of the remaining spaces 143 and 144 lower than S1 and S2 serve as the oil reservoirs 147 and 148. Oil storage 147, 148
Plays the same role as the storage recesses 52 and 53 in the second embodiment.

In the present invention, the following embodiments are also possible. (1) In the second embodiment, the storage recesses 52 and 53
Is omitted.

[0049]

As described in detail above, according to the present invention, oil is sent from the oil-existing area to the accommodating space for accommodating the contact-type sealing means, and the oil sent to the accommodating space is returned to the oil-existing area. An oil passage is provided, and the inlet of the oil passage is provided in the partition wall, the inlet is provided above the rotation shaft, and at least a part of the outlet of the oil passage is provided at a height position of the rotation shaft or less, Since the oil is supplied from the inlet of the oil passage into the oil passage by the scraping action of the oil scraping means, the contact type sealing means for the shaft seal for preventing oil from entering the pump chamber in the vacuum pump is provided. It has an excellent effect that durability can be improved.

[Brief description of the drawings]

FIG. 1 shows a multi-stage roots pump 11 according to a first embodiment.
FIG.

FIG. 2A is a cross-sectional view of a main part on a rotating shaft 19 side. (B)
2 is a sectional side view of a main part on the side of the rotating shaft 20. FIG.

FIG. 3A is a sectional view taken along line AA of FIG. 1; (B) is FIG.
BB sectional drawing of FIG. (C) is a sectional view taken along line CC of FIG. 1.

FIG. 4A is a sectional view taken along the line DD of FIG. (B) is FIG.
Sectional view taken along the line EE of FIG. (C) is a sectional view taken along line FF of FIG. 1.

5A and 5B show a second embodiment, in which FIG.
FIG. (B) is a sectional side view of a main part on the rotating shaft 20 side.

FIG. 6 is a sectional view of a main part.

FIG. 7 is a sectional view of a main part.

FIG. 8 is a graph showing the relationship between the amount of oil and the temperatures of the lip seals 44 and 45.

FIG. 9 shows a third embodiment, in which (a) shows a rotating shaft 19;
FIG. (B) is a sectional side view of a main part on the rotating shaft 20 side.

FIGS. 10A and 10B show a fourth embodiment, in which FIG.
9 is a sectional side view of a main part on the 9th side. (B) is a sectional side view of a main part on the rotating shaft 20 side.

FIG. 11 is a sectional plan view of a main part.

FIG. 12 is a sectional view taken along line GG of FIG. 11;

[Explanation of symbols]

11 Multistage roots pump, which is a vacuum pump. 14 ... Rear housing to be a partition. 143, 144: Remaining space constituting the oil passage. 145, 146 ... accommodation room that becomes the accommodation space. 19, 20 ... rotating shaft. 23 to 32: rotors serving as gas transfer bodies. Reference numeral 331 denotes a gear storage chamber serving as an oil existing area. 3
4, 35: gears constituting a gear mechanism serving as oil scraping means. 37, 38: Radial bearings that serve as bearings. 3
71, 381 ... inner ring. 372, 382: outer ring. 373,
383: gap. 39-43 ... Pump room. 44, 45: Lip seals serving as contact-type sealing means. 47,48,4
9, 50 ... Slits constituting oil passages. 52, 53: storage recesses serving as oil storage sections. 60, 61 ... through holes. Y: Lubricating oil.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F04C 23/00 F04C 23/00 E 25/02 25/02 K 29/02 311 29/02 311K F16J 15 / 32 311 F16J 15/32 311A // F16H 57/04 F16H 57/04 G (72) Inventor Masahiro Kawaguchi 2-1-1 Toyota-cho, Kariya-shi, Aichi Pref. 2-1-1, Toyota-cho, Kariya-shi, Aichi F-term in Toyota Industries Corporation (reference) 3J006 AD01 AE14 3J063 AA40 AC01 BA15 BB03 CA01 CB13 XH03 XH13 XH42

Claims (9)

[Claims] 1. A vacuum pump for moving a gas transfer body in a pump chamber based on rotation of a rotating shaft and transferring a gas by an operation of the gas transfer body to provide a suction action, wherein an oil existing area and the pump chamber are connected to each other. Arranged next to each other, a partition that penetrates the rotation shaft, a peripheral surface of the rotation shaft that penetrates the partition and protrudes into the oil presence area, and a through hole of the partition that penetrates the rotation shaft. And an oil passage for sending oil from the oil-existing area to an accommodating space for accommodating the contact-type sealing means and for returning the oil sent to the accommodating space to the oil-existing area. And an oil scraping means for scraping up the stored oil in the oil existing area, wherein an inlet of the oil passage is provided in the partition wall, and the inlet is provided above the rotary shaft, and an outlet of the oil passage is provided. Little Ku and provided a part below the height position of the rotary shaft, the cooling structure in the vacuum pump so as to supply oil to said oil passage from the inlet of the oil passage by scooping action of the oil scraping up means. 2. A cooling structure in a vacuum pump according to claim 1, wherein said oil passage is adjacent to the entire circumference of said housing space and runs along the entire circumference of said rotary shaft. 3. An oil passage according to claim 2, wherein at least a part of an outlet of said oil passage is provided in said partition, and said outlet provided in said partition is provided below said rotary shaft.
A cooling structure in the vacuum pump according to 1. 4. A bearing for rotatably supporting the rotating shaft is interposed between the partition and the rotating shaft, and the contact-type sealing means is closer to the pump chamber than the bearing. A cooling structure in the vacuum pump according to claim 3. 5. The bearing is a radial bearing,
The gap between the outer ring and the inner ring of the radial bearing,
The cooling structure according to claim 4, wherein the cooling structure is a part of the oil passage and downstream of the housing space. 6. The cooling structure according to claim 5, wherein the outlet of the oil passage is only a gap between an outer ring and an inner ring of the radial bearing. 7. An oil reservoir according to claim 1, wherein an oil reservoir is provided upstream of said outlet so as to communicate with said oil passage and below said outlet. Cooling structure in vacuum pump. 8. The contact type sealing means is a rubber lip seal for preventing oil in the oil existing area from leaking to the pump chamber side along the peripheral surface of the rotary shaft. A cooling structure for the vacuum pump according to claim 7. 9. The vacuum pump according to claim 1, wherein a plurality of said rotating shafts are arranged in parallel, a rotor is arranged on each of said rotating shafts, rotors on adjacent rotating shafts are meshed with each other, and said vacuum pump is in a state of being meshed with each other. A plurality of pump chambers accommodating a plurality of rotors as one set, or a vacuum pump including a single pump chamber, wherein the plurality of rotating shafts are synchronously rotated by using a gear mechanism, and the oil presence region The cooling structure in the vacuum pump according to any one of claims 1 to 8, wherein? Is a region for housing the gear mechanism, and the oil scraping means is the gear mechanism.