JP2015190331A - vacuum pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum pump that reduces vibrations to be transmitted to the outside and has high heat dissipation performance.SOLUTION: A rolling bearing 8 that pivotally supports a shaft 10 of a rotating body unit R is elastically supported by an elastic support body 14. The elastic support body 14 comprises an annular body 15 and a plurality of elastic parts 16 extended in an approximately circumferential direction from an outer peripheral surface of the annular body 15. Because the diameter of outer peripheral surfaces 16b1 of the elastic parts 16 is set so as to be slightly smaller than the diameter of an inner peripheral surface 41a of a concave part of an upper bearing housing 41, the outer peripheral surfaces 16b1 are opposed to the inner peripheral surface 41a, and they are not in contact with each other or they are partially in contact with each other even if they are in contact with each other. End parts 16c extended from one axial end of each of ends of the elastic parts 16 are slidably in contact with a lower surface 41b of the upper bearing housing 41 via surfaces 16c1 on the side of an inlet port due to a preload by which the rotating body unit R is pulled toward the side of the inlet port.

Description

  The present invention relates to a vacuum pump.

  In a vacuum pump that supports a pump rotating body with a rolling bearing, axial support and radial support of the rolling bearing may be performed by an elastomer elastic body that contacts the axial end face and the outer peripheral side of the outer ring of the rolling bearing. Furthermore, the elastomer elastic body is also in contact with the bearing housing. And the reduction of the run-out at the time of dangerous speed passage is aimed at using the damping action by compression deformation of an elastomer elastic body.

  By the way, the heat from the pump rotating body is transferred through a heat transfer path configured in the order of the rolling bearing, the elastic support, and the bearing housing. Since the elastomer elastic body has a low thermal conductivity, there is a problem that heat cannot be sufficiently transferred from the rolling bearing to the bearing housing. For this reason, there is a problem that the temperature of the rolling bearing rises, the evaporation of the base oil of the grease that lubricates the rolling bearing is accelerated, and the life is shortened.

  Patent Document 1 discloses an invention of an elastic support made of metal. Since the metal has a higher thermal conductivity than the elastomer elastic body, the metal is excellent in heat dissipation. In addition, as for the elastic support body of patent document 1, the flexible member has connected the inner side annular part and the outer side annular part. And in the elastic support body of patent document 1, the heat by the side of a pump rotary body is transmitted in order of an inner annular part, a flexible member, and an outer annular part.

Special table 2008-542628 gazette

  The elastic support body may adjust the radial support rigidity (hereinafter, radial support rigidity) of the rolling bearing by design. When it is necessary to reduce the radial support rigidity, the elastic support described in Patent Document 1 is a plate spring fixed at both ends because the flexible member connects the inner annular portion and the outer annular portion. In order to obtain an appropriate rigidity, it is necessary to make the flexible member thin and long. Since the flexible member plays not only a role having elasticity but also a role as a heat transfer path, if the flexible member becomes thin and long, the resistance of the heat transfer path becomes high, and the heat transfer deteriorates.

For the purpose of facilitating understanding of the present invention, the present invention will be described with reference to the embodiment, but the technical scope of the present invention is not limited to the embodiment.
(1) A vacuum pump according to a preferred first aspect of the present invention includes a pump casing 12 having an intake port, a rolling bearing 8 that is accommodated in the pump casing and supports the rotor assembly R, and a rolling bearing 8 is accommodated. The base 2 provided with the bearing housing 40 and the elastic support 14 provided in the bearing housing 40 and elastically supporting the rolling bearing 8 are provided. The elastic support body 14 includes an annular body 15 that fits to the outer ring 8 a of the rolling bearing 8, and a plurality of elastic portions 16 that extend from the outer circumferential surface of the annular body 15 in a substantially circumferential direction and that have free ends at their tips. . The annular body 15 is elastically supported by the bearing housing 40 by the contact between the elastic portion 16 and the bearing housing 40.
(2) A vacuum pump according to a preferred second aspect of the present invention is the vacuum pump according to the first aspect. In the rolling bearing 8, the outer peripheral surface 16b1 of the elastic portion 16 and the inner peripheral surface 41a of the bearing housing 40 are in contact with each other. Thus, the surface 16c1 on the inlet side of the tip 16c of the elastic portion 16 is brought into contact with the outer surface 41b in the axial direction of the bearing housing 40 and elastically supported in the axial direction.
(3) A preferred third aspect of the present invention is the vacuum pump according to the first or second aspect, wherein each of the elastic portions 16 is separated from the outer peripheral surface 15e of the annular body 15 by a predetermined distance in the radial direction. And an elastic arm portion 16b disposed as a double ring structure, and a distal end portion 16c extending radially outward at the distal end of the elastic arm portion 16b, and a surface on the inlet side of the distal end portion 16c. 16c1 is slidably opposed to the bearing housing 40.
(4) A vacuum pump according to a preferred fourth aspect of the present invention is the vacuum pump according to any one of the first to third aspects, wherein the lower part of the rotor assembly R is supported by a rolling bearing 8, and the rotor assembly R The upper portion is supported by a permanent magnet type magnetic bearing 6, and the surface 16 c 1 on the inlet side of the tip end portion 16 c of the elastic portion 16 is brought into contact with the bearing housing 40 by the axial repulsive force of the permanent magnet type magnetic bearing 6.
(5) The vacuum pump according to a preferred fifth aspect of the present invention is the vacuum pump according to any one of the first to fourth aspects, wherein the annular body 15 is inserted and fitted into the inner peripheral surface 15a1 of the outer ring 8a of the rolling bearing 8. A cylindrical base portion 15a to be joined, first and second extension portions 15b and 15c extending in the axial direction from both axial ends of the cylindrical base portion 15a, and extending radially inward from the first extension portion 15b. And an annular portion 15d for restricting movement of the outer ring 8a of the rolling bearing 8 in the axial direction.
(6) A vacuum pump according to a sixth aspect of the present invention is the vacuum pump according to the fifth aspect, wherein the outer peripheral surfaces of the first and second extension portions 15b and 15c of the annular body 15 and the inner periphery of the bearing housing 40 are used. Elastomeric elastic bodies 19a and 19b for restricting the radial movement of the elastic support body 14 are provided between the surfaces.
(7) A vacuum pump according to a preferred seventh aspect of the present invention is the vacuum pump according to the sixth aspect, wherein the spaces 51 and 52 are surrounded by the elastic support body 14, the elastomer elastic bodies 19a and 19b, and the bearing housing 40. Is filled with grease.
(8) A vacuum pump according to a preferred eighth aspect of the present invention is the vacuum pump according to any one of the first to seventh aspects, wherein grease is provided between the outer peripheral surface 16b1 of the elastic portion 16 and the bearing housing 40. Grease is provided between the tip end portion 16c of the elastic portion 16 and the bearing housing 40 with which the tip end portion 16c of the elastic portion 16 abuts.
(9) The vacuum pump according to a preferred ninth aspect of the present invention is the vacuum pump according to any one of the first to eighth aspects, facing the outer peripheral surface 16b1 of the elastic portion 16 and the outer peripheral surface 16b1 of the elastic portion 16. A material layer having a lower coefficient of friction than the elastic support 14 and the bearing housing 40 is provided on any one of the surfaces 41a of the bearing housing 40, and the distal end portion 16c of the elastic portion 16 and the distal end portion 16c of the elastic portion 16 A material layer having a lower coefficient of friction than the elastic support 14 and the bearing housing 40 is provided on one of the surfaces 41 b of the bearing housing 40 that abuts.

  According to the present invention, since the elastic portion of the elastic support is a cantilever beam having a free end at the tip, even if the cross-sectional area of the elastic portion is increased, the rigidity of the elastic portion can be relatively reduced and vibration to the outside can be achieved. The heat dissipation performance can be improved while reducing the above.

The figure which showed the turbo-molecular pump 1 of one Embodiment. The figure which showed the inside of the bearing housing 40. FIG. The figure which showed the elastic support body. The figure for comparing the elastic support body 14 and the elastic support body 80 of patent document 1

  FIG. 1 is a diagram showing an embodiment of a vacuum pump according to the present invention, and is a cross-sectional view of a turbo molecular pump 1. The turbo molecular pump 1 is connected to a power supply unit that supplies power, but is not shown in FIG.

The turbo molecular pump 1 shown in FIG. 1 includes a base 2 and a pump casing 12, and these constitute a pump container. In the pump container, a turbo pump part P1 provided with turbine blades and a Holweck pump part P2 which is a thread groove pump provided with a spiral groove are provided as an exhaust function part.
The turbo pump unit P1 includes a plurality of stages of rotary blades 30 formed on the pump rotor 3 and a plurality of stages of fixed blades 20 disposed on the pump casing 12 side. On the other hand, the Holweck pump part P2 provided on the exhaust downstream side of the turbo pump part P1 is composed of a rotor cylindrical part 31 formed on the pump rotor 3 and a stator 21 arranged on the base 2 side. A spiral groove is formed on the inner peripheral surface of the cylindrical stator 21. The rotary blade 30 and the rotor cylindrical portion 31 constitute a rotation side exhaust function unit, and the fixed blade 20 and the stator 21 constitute a fixed side exhaust function unit.

  The pump rotor 3 is fastened to the shaft 10, and the shaft 10 is rotationally driven by the motor 4. For example, a DC brushless motor is used as the motor 4, a motor stator 4a is provided on the base 2, and a motor rotor 4b is provided on the shaft 10 side. The rotating body unit R including the shaft 10 and the pump rotor 3 is rotatably supported by a permanent magnet type magnetic bearing 6 using the permanent magnets 6 a and 6 b and a rolling bearing 8.

  The permanent magnets 6 a and 6 b are ring-shaped permanent magnets magnetized in the axial direction, and support the upper end of the shaft 10. A plurality of permanent magnets 6a provided in the pump rotor 3 are arranged in the axial direction so that the same poles face each other. On the other hand, the plurality of fixed-side permanent magnets 6 b are attached to a magnet holder 11 fixed to the pump casing 12. A plurality of these permanent magnets 6b are also arranged in the axial direction so that the same poles face each other. The axial direction position of the permanent magnet 6a provided in the pump rotor 3 is set to be slightly above the position of the permanent magnet 6b disposed on the inner peripheral side thereof. In other words, the magnetic pole of the permanent magnet 6a on the rotating side is shifted by a predetermined amount in the axial direction with respect to the magnetic pole of the permanent magnet 6b on the fixed side. The supporting force of the permanent magnet type magnetic bearing 6 varies depending on the size of the predetermined amount. In the example shown in FIG. 1, since the permanent magnet 6a is disposed on the upper side in the drawing, the repulsive force between the permanent magnet 6a and the permanent magnet 6b causes the radial support force and the axial upward direction (the pump inlet side direction). ) Is acting on the rotary unit R.

  A bearing holder 13 that holds the rolling bearing 9 is fixed at the center of the magnet holder 11. A support part 13a supported by the magnet holder 11 is formed above the bearing holder 13 in the figure, and a rolling bearing holding part 13b is formed below the figure. The rolling bearing holding portion 13b is recessed from the lower end of the bearing holder 13, and the outer ring of the rolling bearing 9 is held on the inner peripheral surface thereof. At the center of the inner ring of the rolling bearing 9, the upper end of the shaft 10 is arranged with a predetermined gap in the radial direction. As the rolling bearing 9, for example, a deep groove ball bearing is used.

  The rolling bearing 9 functions as a touch-down bearing that limits the radial deflection of the upper part of the shaft. In a steady rotation state, the shaft 10 and the rolling bearing 9 do not come into contact with each other, and when a large disturbance is applied or when the rotation of the shaft 10 increases during rotation acceleration or deceleration, the shaft 10 is in rolling contact. 9 is contacted.

The lower end of the shaft 10 is pivotally supported by a bearing device BA having a rolling bearing 8 (described later) held in a bearing housing 40 provided on the base 2. As the rolling bearing 8, for example, a deep groove ball bearing is used. Since the rolling bearing 8 always supports and supports the rotating body unit R, grease is sealed inside.
In FIG. 1, the bearing housing 40 and the bearing device BA held therein are illustrated in a simplified manner. Details are shown in FIG.

The bearing housing 40 and the bearing device BA held by the bearing housing 40 will be described with reference to FIGS. 2 and 3. FIG. 2 is a longitudinal sectional view of the bearing housing 40 and the bearing device BA.
The bearing housing 40 will be described.
As described above, the bearing device BA that supports the lower end of the shaft 10 of the rotating body unit R is held in the bearing housing 40. The bearing housing 40 includes an upper bearing housing 41 and a lower bearing housing 42. The upper bearing housing 41 and the lower bearing housing 42 are made of a metal material such as stainless steel. The upper bearing housing 41 is formed integrally with the base 2, and the lower bearing housing 42 is provided as a separate member from the base 2. The annular lower bearing housing 42 is screwed and fixed to a female screw 41 c formed on the inner peripheral surface of the recess of the upper bearing housing 41 by a male screw 42 b formed on the outer peripheral surface.

The bearing device BA will be described with reference to FIG.
The bearing device BA mainly includes a rolling bearing 8, an elastic support body 14, an elastomer elastic body 19a, and an elastomer elastic body 19b shown in detail in FIG.
The shaft 10 of the rotating body unit R is inserted and fitted to the inner ring 8 b of the rolling bearing 8, the outer ring 8 a of the rolling bearing 8 is fitted to the annular body 15 of the elastic support 14, and the elastic support 14 is attached to the bearing housing 40. Contained. Although described in detail later, the rolling bearing 8 is elastically supported by the bearing housing 40 by such a bearing device BA.

  In FIG. 2, only the cross section of the elastic support 14 is a cross section taken along line BB shown in FIG. 3. The elastomer elastic body 19a and the elastomer elastic body 19b are collectively referred to as an elastomer elastic body 19. Specific examples of the elastomer elastic body 19 include an O-ring, a square ring, and an oil seal.

The elastic support 14 will be described with reference to FIGS. 2 and 3.
FIG. 3 is a plan view of the elastic support member 14 as viewed from the air inlet side, that is, an arrow view indicated by A in FIG. As can be seen from FIG. 2, the elastic support 14 which is an annular body flat in the axial direction is composed of one annular body 15 and a plurality of elastic portions 16 as shown in FIG. 3. FIG. 3 shows a case where there are three elastic portions 16.

  Stainless steel or the like is used for the elastic support 14, but it is preferable to use a spring metal material, more preferably a high damping metal material such as a Mn-Cu-based material or a Mn-Cu-Ni-Fe-based material. It is preferable to use (also called a damping alloy). By forming the elastic support 14 with a high damping metal material, vibration transmitted to the elastic support 14 is attenuated by the elastic support 14 itself, and vibration transmission to the pump base side can be further reduced.

  As shown in FIG. 2, the annular body 15 of the elastic support member 14 includes a cylindrical cylindrical base portion 15 a having an axial length, that is, the same thickness as an elastic arm portion 16 b of the elastic portion 16 described later, and a base portion 15 a. Cylindrical end portions 15b and 15c having both axial end surfaces extending in the axial direction, and an annular portion 15d extending in the radial direction from the inner peripheral surface of the upper cylindrical extension portion 15b in FIG. It has.

  Each elastic portion 16 extends from the outer peripheral surface 15 e of the annular body 15 in a substantially circumferential direction. More specifically, each elastic portion 16 includes a connecting portion 16a connected to the cylindrical base portion 15a of the annular body 15, and a predetermined distance from the outer peripheral surface 15e of the annular body 15 from the connecting portion 16a. The elastic arm portion 16b has a double structure on the side, and a distal end portion 16c that protrudes radially outward from one axial end side of the outer peripheral surface 16b1 at the distal end portion of the elastic arm portion 16b.

  As described above, the rotating body unit R is pulled toward the intake port by the permanent magnet type magnetic bearing 6. The elastic support member 14 is in contact with the lower surface 41b of the upper bearing housing 41 via the suction port side surface 16c1 of the tip end portion 16c when the rotating body unit R is pulled toward the suction port side. That is, a preload is applied to the bearing device BA by the permanent magnet type magnetic bearing 6.

  Grease for reducing friction is applied or filled between the surface 16c1 and the lower surface 41b that contact each other. The elastic support 14 faces the inner peripheral surface 41 a of the recess of the upper bearing housing 41 through the outer peripheral surface 16 b 1 of the elastic portion 16. Since the diameter of the outer peripheral surface 16b1 of the elastic portion 16 is set slightly smaller than the diameter of the inner peripheral surface 41a of the recess of the upper bearing housing 41, the outer peripheral surface 16b1 and the inner peripheral surface 41a are not in contact with each other. Or even if they are in contact, only a part of the contact is made. Grease is also applied or filled between the outer peripheral surface 16b1 and the inner peripheral surface 41a.

  A material layer having a lower coefficient of friction than the elastic support 14 and the upper bearing housing 41 is formed on at least one of the intake port side surface 16c1 of the distal end portion 16c of the elastic support 14 and the lower surface 41b of the upper bearing housing 41. Has been. In addition, a material layer having a lower friction coefficient than the elastic support 14 and the upper bearing housing 41 is formed on at least one of the outer peripheral surface 16b1 of the elastic portion 16 and the inner peripheral surface 41a of the recess of the upper bearing housing 41. Yes. A material layer having a friction coefficient of 0.2 or less is desirable.

  As described above, the shaft 10 of the rotating body unit R is inserted and fitted into the inner ring 8b of the rolling bearing 8, and the outer circumferential surface of the outer ring 8a of the rolling bearing 8 is connected to the inner circumferential surface 15a1 of the annular body 15 of the elastic support member 14. It is mated. Since the annular body 15 is elastically supported by the bearing housing 40 by the three elastic portions 16, the rolling bearing 8 is elastically supported by the bearing housing 40 by the elastic support body 14.

  As described above, the cylindrical extension 15b extends from one end in the axial direction of the annular body 15 of the elastic support 14 on the inlet side, that is, the upper end in the illustrated axial direction. Further, an annular portion 15d is extended on the inner peripheral side of the cylindrical extension portion 15b. An elastomer elastic body, for example, an O-ring 19a, is provided between the cylindrical extension 15b and the upper bearing housing 41 in the radial direction. A space 51 indicated by hatching surrounded by the elastic support body 14, the elastomer elastic body 19a, and the upper bearing housing 41 is filled with grease.

As described above, the cylindrical extension 15c extends from one end in the axial direction of the annular support 15 on the exhaust port side. An elastomer elastic body, for example, an O-ring 19b is provided between the cylindrical extension 15c and the lower bearing housing 42 in the radial direction. The space 52 indicated by hatching surrounded by the elastic support body 14, the elastomer elastic body 19b, the lower bearing housing 42, and the upper bearing housing 41 is filled with grease.
The gap 156 between the annular body 15 and the elastic portion 16 is also filled with grease.

FIG. 4A is a diagram schematically showing the elastic support 14 and shows a state in which the elastic support 14 is disposed in the bearing housing 40. FIG. 4B is a view schematically showing the elastic support 80 described in Patent Document 1, and shows a state in which the elastic support 80 is disposed in the bearing housing 40.
As shown in FIG. 2, the elastic support 14 contacts the bearing housing 40 on the outer peripheral surface 16b1 and the distal end portion 16c1 of the elastic portion 16, and therefore in FIG. Reference numerals 16b1 and 16c1 are attached to the tips of the bearings, and reference numerals 41a and 41b are attached to the contact surfaces of the bearing housing 40.

  4A and 4B, the elastic support body 14 of the present embodiment and the elastic support body 80 described in Patent Document 1 will be compared. Note that the elastic portion 16 of the elastic support body 14 of the present embodiment corresponds to the flexible member 84 of the elastic support body 80 described in Patent Document 1. Further, the annular body 15 of the elastic support body 14 of the present embodiment corresponds to the inner annular portion 86 of the elastic support body 80 described in Patent Document 1.

  Below, the elastic support body 14 of this embodiment and the elastic support body 80 of patent document 1 are compared by the case where it produces as an elastic support body which has the same radial direction support rigidity.

  The elastic support 14 of this embodiment shown in FIG. 4A can slide with respect to the bearing housing 40 as described above. Further, the elastic support 14 of the present embodiment does not have a configuration corresponding to the outer annular portion 88 of the elastic support 80 described in Patent Document 1, and the elastic portion 16 of the elastic support 14 of the present embodiment is cantilevered. The beam structure is a fixed end connected to the annular body 15 at the base end, and the free end is the distal end on the outer peripheral side.

  On the other hand, the flexible member, that is, the elastic portion 84 of the elastic support body 80 described in Patent Document 1 shown in FIG. 4B connects the inner annular portion, that is, the annular body 86 and the outer annular portion 88. That is, the flexible member 84 of the elastic support 80 described in Patent Document 1 is integrally formed on the outer annular portion 88 on the outer peripheral side and integrally formed on the inner annular portion 86 on the inner peripheral side. . That is, the elastic portion 84 of the elastic support 80 has a double-supported beam structure in which both ends are fixed ends.

  As described above, the distal end on the outer peripheral side of the elastic portion 16 of the elastic support 14 of the present embodiment is slidable and a free end, and the flexible member 84 of the elastic support 80 described in Patent Document 1 is Both the outer peripheral tip and the inner peripheral tip are fixed ends. This difference affects the radial support stiffness. When having the same radial support rigidity, the elastic part having the open end can increase the cross-sectional area and shorten the overall length, compared with the elastic part having no open end and only a fixed end. Thereby, the elastic support body 14 of this embodiment can make resistance of the heat-transfer path | route which flows from an annular body to a housing lower than the elastic support body 80 of patent document 1. FIG. As a result, the elastic support 14 of this embodiment has higher heat dissipation performance than the elastic support 80 described in Patent Document 1.

According to the embodiment described above, the following operational effects are obtained.
(1) In the vacuum pump according to the embodiment, the rolling bearing 8 that supports the rotor assembly R to which the axial force is applied in advance is provided in the bearing housing 40, and the rolling bearing 8 is elastically supported by the elastic support body 14. The elastic support body 14 includes an annular body 15 that fits to the outer ring 8a of the rolling bearing 8 and a plurality of elastic portions 16 that extend from the outer peripheral surface 15e of the annular body 15 in a substantially circumferential direction and that have free ends at their distal ends. Prepare. The annular body 15 is elastically supported by the bearing housing 40 by the contact between the elastic portion 16 and the bearing housing 40.
Since the elastic support body 14 is elastically supported by the bearing housing 40 by the elastic part 16 of the cantilever whose free end is a free end, the elastic part is more elastic than the case where the elastic part 16 is a double-supported beam as in the prior art. When the cross-sectional area of 16 is increased, the overall length can be shortened, and the heat radiation performance for transferring the heat generated inside to the bearing housing 40 is improved.

(2) The rolling bearing 8 is elastically supported in the radial direction by contacting the outer peripheral surface 16b1 of the elastic portion 16 and the inner peripheral surface 41a of the upper bearing housing 41. Further, the rolling bearing 8 is elastically supported in the axial direction with the suction port side surface 16c1 of the tip portion 16c of the elastic portion 16 in contact with the lower surface 41b of the upper bearing housing 41 in the axial direction.
Thus, in the vacuum pump of the embodiment, the rolling bearing 8 is elastically supported in the axial direction and the radial direction by the elastic portion 16, so that even if the rolling bearing 8 vibrates in the axial direction and the radial direction, it is absorbed by the elastic support body 14. can do.

(3) Each of the elastic portions 16 has an elastic arm portion 16b disposed as a double ring structure with a predetermined distance in the radial direction from the outer peripheral surface 15e of the annular body 15, and a diameter at the tip of the elastic arm portion 16b. And a tip portion 16c extending outward in the direction. The front end portion 16c is slidably opposed to the bearing housing 40.
When the outer ring 8 a of the rolling bearing 8 is rotated by the rotation of the shaft 10, the distal end portion 16 c of the elastic portion 16 slides with respect to the bearing housing 40.

(4) The lower part of the rotor assembly R is supported by the rolling bearing 8, and the upper part of the rotor assembly R is supported by the permanent magnet type magnetic bearing 6. The axial force is applied to the rotor assembly R by the repulsive force in the axial direction of the permanent magnet type magnetic bearing 6, and the suction port side surface 16 c 1 of the distal end portion 16 c of the elastic portion 16 is brought into contact with the lower surface 41 b of the upper bearing housing 41. The

(5) The annular body 15 includes a cylindrical base portion 15a into which the outer ring 8a of the rolling bearing 8 is inserted and fitted into the inner peripheral surface 15a1, and first and second extending in the axial direction from both axial ends of the cylindrical base portion 15a. Extension portions 15b and 15c and an annular portion 15d that extends radially inward from the first or second cylindrical extension portions 15b and 15c and restricts the axial movement of the outer ring 8a of the rolling bearing 8 due to the repulsive force. And have. The position of the rolling bearing 8 in the axial direction is regulated by the annular portion 15 d, and the axial vibration of the rolling bearing 8 can be reliably transmitted to the elastic support 14. The rotor assembly R is pivoted by the elastic support 14. Elastically supported in the direction.

(6) An elastomer elastic body that restricts radial movement of the elastic support 14 between the outer peripheral surfaces of the first and second cylindrical extensions 15b and 15c of the annular body 15 and the inner peripheral surface of the bearing housing 40. 19a and 19b are provided.
Since the elastomer elastic bodies 19a and 19b are provided, the vibration transmitted to the outside of the pump can be suppressed similarly to the elastic support body 14. That is, it is possible to assist the suppression of vibration of the elastic support 14. The elastomer elastic bodies 19a and 19b can prevent grease from flowing out and evaporating. Furthermore, since the elastomer elastic bodies 19a and 19b are provided at both ends of the elastic support body 14 in the axial direction, the outer ring 8a of the rolling bearing 8 can be prevented from being inclined.

(7) Grease is filled in the spaces 51 and 52 surrounded by the elastic support body 14, the elastomer elastic bodies 19a and 19b, and the bearing housing 40.
Thereby, when the elastic support body 14 slides, the elastomer elastic bodies 19a and 19b can reduce friction with the bearing housing 40. Further, through the grease, the heat from the rotating body unit R can be transmitted to the bearing housing 40 side. That is, grease can be used as a heat transfer path. Therefore, heat is dissipated through the grease even at a location where the outer peripheral surface 16b1 of the elastic portion 16 is separated from the housing 40, so that the heat dissipation performance is improved.

(8) An upper bearing in which grease is provided between the outer peripheral surface 16b1 of the elastic portion 16 and the inner peripheral surface 41a of the concave portion of the upper bearing housing 41, and the surface 16c1 on the inlet side of the tip portion 16c contacts the tip portion 16c. Grease is provided between the lower surface 41 b of the housing 41. Since heat is dissipated through grease, the heat dissipation performance is improved.
As a result, the elastic support 14 can easily slide, and the radial support rigidity can be lowered. Then, frictional heat between the elastic support 14 and the upper bearing housing 41 can be reduced. Furthermore, the heat from the rotating body unit R can be transmitted to the bearing housing 40 side via grease. That is, grease can be used as a heat transfer path.
Instead of applying grease, the suction port side of the distal end portion 16c of the elastic portion 16 that contacts between the outer peripheral surface 16b1 of the elastic portion 16 and the inner peripheral surface 41a of the concave portion of the upper bearing housing 41 facing each other. Grease may be filled between the surface 16c1 of the upper surface and the lower surface 41b of the upper bearing housing 41.

(9) A material layer having a lower friction coefficient than the elastic support 14 and the upper bearing housing 41 is provided on the contact surfaces of the elastic portion 16 and the upper bearing housing 41 that are in contact with each other. In the embodiment, a material layer having a low friction coefficient is provided on one of the outer peripheral surface 16b1 of the elastic portion 16 and the surface 41a of the upper bearing housing 41 facing the outer peripheral surface 16b1 of the elastic portion 16. In addition, a material layer having a lower coefficient of friction than the elastic support 14 and the upper bearing housing 41 is provided on one of the inlet port side surface 16c1 of the distal end portion 16c and the lower surface 41b of the upper bearing housing 41 in contact with the distal end portion 16c. Is provided.
Therefore, the frictional resistance when the outer ring 8a of the rolling bearing 8 is rotated by the rotation of the shaft 10 and the elastic portion 16 slides on the contact surface of the upper bearing housing 41 can be suppressed. In other words, the elastic support 14 can easily slide, and the radial support rigidity can be lowered. Further, frictional heat between the elastic support 14 and the upper bearing housing 41 can be reduced.

(10) The elastic support 14 is made of a metal such as stainless steel, a copper alloy, or a spring metal material. As a result, the heat radiation performance is higher than that of the vacuum pump that supports the rotating body unit only by the elastomer elastic body having a lower thermal conductivity than that of the metal. In addition, since the elastic modulus of the metal is less likely to change depending on temperature, time, grease, or the like than the elastomer elastic body, the radial support rigidity can be stabilized.

The embodiment described above can be implemented by being modified as follows.
(1) In the above-described embodiment, as described with reference to FIG. 2, the permanent magnet type magnetic bearing 6 causes the suction port side surface 16 c 1 of the distal end portion 16 c of the elastic support 14 to abut the lower surface 41 b of the upper bearing housing 41. ing. This is due to a preload condition generated between the rolling bearing 8 and the rotating body unit R given by the pulling force by the permanent magnet type magnetic bearing 6.

  For example, when the air inlet side of the rotating body unit R is supported by a rolling bearing instead of a permanent magnet type magnetic bearing, a preload is generated by pressing the rotating body unit R between the upper and lower rolling bearings. The rolling bearing 8 on the exhaust port side that supports the rotating body unit R shown in 2 receives the force on the intake port side from the elastic support member 14. In order to achieve this, the elastic support 14 must receive a force on the inlet side from the lower bearing housing 42. As a result, the elastic support member 14 comes into contact with the upper surface 42a of the lower bearing housing 42 via the exhaust port side surface 16c2 of the distal end portion 16c. Even in such a contact state, the elastic support 14 can slide. In this case, grease may be provided on the surface 16c2 and the upper surface 42a, and at least one of the surface 16c2 and the upper surface 42a may be provided with a material layer having a lower coefficient of friction than the elastic support member 14 and the lower bearing housing 42. That's fine.

(2) In the embodiment described above, the upper bearing housing 41 is formed integrally with the base 2. However, the upper bearing housing 41 may be made of a member different from the base 2 and attached to the base 2. .
(3) Although three elastic portions 16 of the elastic support 14 are provided, four or more elastic portions 16 may be provided.
(4) The present invention is not limited to a vacuum pump having a turbo pump part P1 and a Holweck pump part P2 in the exhaust function part, but only a vacuum pump having only turbine blades, a drag pump such as a Ziegburn pump or a Holweck pump. The present invention can also be applied to a vacuum pump equipped with the above or a vacuum pump that combines them.

  The present invention is not limited to the contents described above. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

1: turbo molecular pump, 2: base,
3: Pump rotor, 4: Motor,
4a: motor rotor, 4b: motor stator,
6: Permanent magnet type magnetic bearing, 8: Bearing,
8a: outer ring, 8b: inner ring,
9: bearing, 10: shaft,
11: Magnet holder, 12: Pump casing,
13: Bearing holder, 14: Elastic support,
15: annular body, 15a: base,
15b, 15c: cylindrical extension part, 15d: annular part,
15e: outer peripheral surface, 15a1: inner peripheral surface,
16: Elastic part, 16a: Base part,
16b: elastic arm portion, 16b1: outer peripheral surface,
16c: tip portion, 16c1: intake side surface,
19, 19a, 19b: elastomer elastic body,
20: fixed wing, 21: stator
30: Rotor 31: Rotor cylindrical part,
40: bearing housing, 41: upper bearing housing,
41a: inner peripheral surface, 41b: lower surface,
42: Lower bearing housing, 42a: Upper surface,
80: elastic support, 84: flexible member,
86: inner annular portion, 88: outer annular portion,
156: Clearance, P1: Turbo pump part,
P2: Holweck pump part, R: Rotating body unit

Claims (9)

A pump casing having an inlet,
A rolling bearing housed in the pump casing and supporting the rotor assembly;
A base provided with a bearing housing in which the rolling bearing is accommodated;
An elastic support provided in the bearing housing and elastically supporting the rolling bearing;
The elastic support includes an annular body that fits to an outer ring of a rolling bearing, and a plurality of elastic portions that extend in a substantially circumferential direction from the outer circumferential surface of the annular body and have tips that are free ends.
The annular body is a vacuum pump that is elastically supported by the bearing housing by contact between the elastic portion and the bearing housing. The vacuum pump according to claim 1, wherein
In the rolling bearing, the outer peripheral surface of the elastic portion and the inner peripheral surface of the bearing housing are in contact with each other and elastically supported in the radial direction, and the outer surface in the axial direction of the tip portion of the elastic portion is the axial direction of the bearing housing. A vacuum pump that is elastically supported in the axial direction while being in contact with the outer surface. The vacuum pump according to claim 1 or 2,
Each of the elastic portions includes an elastic arm portion disposed as a double ring structure at a predetermined distance in the radial direction from the outer peripheral surface of the annular body, and extends radially outward at the tip of the elastic arm portion. A vacuum pump having a distal end portion provided, the outer surface of the distal end portion being slidably opposed to the bearing housing. The vacuum pump according to any one of claims 1 to 3,
The lower part of the rotor assembly is supported by the rolling bearing,
The upper part of the rotor assembly is supported by a permanent magnet type magnetic bearing,
A vacuum pump in which one axial outer surface of the distal end portion of the elastic portion is brought into contact with the bearing housing by an axial repulsive force of the permanent magnet type magnetic bearing. The vacuum pump according to any one of claims 1 to 4,
The annular body includes a cylindrical base portion into which an outer ring of the rolling bearing is inserted and fitted to an inner peripheral surface, and first and second cylindrical extension portions extending in the axial direction from both axial ends of the cylindrical base portion, A vacuum pump having an annular portion that extends radially inward from the first cylindrical extension and restricts axial movement of the outer ring of the rolling bearing. The vacuum pump according to claim 5,
Between the outer peripheral surface of the first and second cylindrical extensions of the annular body and the inner peripheral surface of the bearing housing, an elastomer elastic body that restricts radial movement of the elastic support is provided. Vacuum pump. The vacuum pump according to claim 6,
A vacuum pump in which grease is filled in a space surrounded by the elastic support, the elastomer elastic, and the bearing housing. The vacuum pump according to any one of claims 1 to 7,
Grease is provided between the outer peripheral surface of the elastic portion and the bearing housing,
A vacuum pump in which grease is provided between a distal end portion of the elastic portion and the bearing housing in contact with the distal end portion of the elastic portion. The vacuum pump according to any one of claims 1 to 8,
A material layer having a lower coefficient of friction than the elastic support and the bearing housing is provided on either the outer peripheral surface of the elastic portion or the surface of the bearing housing facing the outer peripheral surface of the elastic portion. ,
A vacuum in which a material layer having a lower friction coefficient than that of the elastic support and the bearing housing is provided on one of the tip of the elastic portion and the surface of the bearing housing that contacts the tip of the elastic portion. pump.

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