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EP-3951185-B1 - VACUUM PUMP WITH INTAKE OPENING FLANGE

EP3951185B1EP 3951185 B1EP3951185 B1EP 3951185B1EP-3951185-B1

Inventors

  • YOSHIHARA, Nahoko
  • SAKAGUCHI, YOSHIYUKI
  • OGAWA, YOHEI

Dates

Publication Date
20260513
Application Date
20200313

Claims (5)

  1. A vacuum pump (1) , comprising: an inlet port flange (100) to be coupled to an apparatus; a casing (2) which functions as a housing for covering internal members; an outlet port (6); a base portion (3); and a rotating portion (9, 10) which is enclosed by and rotatably supported by the casing (2) and the base portion (3), wherein the inlet port flange (100) and the casing (2) are formed as separate components, the casing (2) is made of aluminum, and the inlet port flange (100) and the casing (2) are fastened to each other at an inlet port (4) of the casing using a plurality of fastening bolts (800); characterized in that respective heads of the plurality of fastening bolts (800) are exposed to the inlet port (4).
  2. The vacuum pump (1) according to claim 1, wherein the inlet port flange (100) is made of stainless steel.
  3. The vacuum pump (1) according to claim 1 or 2, wherein the casing (2) is provided with a projecting portion (900) for performing positioning when fastening the casing (2) to the inlet port flange (100).
  4. The vacuum pump (1) according to claim 3, wherein the projecting portion (900) or the inlet port flange (100) is provided with a release portion (920, 940) for absorbing fracture energy.
  5. The vacuum pump (1) according to claim 4, wherein an inlet port flange-side release portion (940) for absorbing fracture energy from the projecting portion (900) is provided at a position that comes into contact with the projecting portion (900) of the casing (2) when fastening the inlet port flange (100) to the casing (2).

Description

The present invention relates to a vacuum pump in which an outer cylinder and a flange that are components of the vacuum pump are separately constructed. Molecular pumps (vacuum pumps) such as turbo-molecular pumps and thread groove pumps are often used to exhaust semiconductor manufacturing apparatuses and used as vacuum containers of electron microscopes or the like which require a high vacuum. Such vacuum pumps are usually provided with a flange of a predetermined size and are configured to be fixed by bolts or the like to an outlet port-side flange (hereinafter, referred to as an apparatus-side flange) of a vacuum apparatus (hereinafter, referred to as an apparatus) that requires exhaust. High airtightness is maintained between the flange of the vacuum pump (hereinafter, the flange of the vacuum pump will be referred to as an inlet port flange) and the apparatus-side flange by fixing the inlet port flange and the apparatus-side flange to each other while sandwiching an O-ring therebetween. The vacuum pump is provided with a rotor which is rotatably supported and which is capable of being rotated at high speed by a motor and a stator which is fixed to an inside of a casing of the vacuum pump. When the motor rotates at high speed, an exhaust action is exhibited due to an interaction between the rotor and the stator. Due to the exhaust action, gas on the apparatus side is sucked from an inlet port of the vacuum pump and exhausted through an outlet port of the vacuum pump. A high-vacuum state inside the apparatus is realized in this manner. Usually, the vacuum pump exhausts gas in a molecular flow region (a region with a high degree of vacuum in which particles less frequently collide with each other). In order to exhibit exhaust performance in the molecular flow region, the rotor is required to rotate at a high speed of around 30,000 rotations per minute. FIG. 7 is a diagram for describing a vacuum pump according to conventional art. As shown in the diagram, an outer side of a vacuum pump 1 is formed by a casing (outer cylinder) 2, an inlet port flange 200, and a base 3. Among these components, the casing (outer cylinder) 2 and the inlet port flange 200 are integrally formed as a single component. There are other vacuum pumps in which both components are manufactured as separate components and subsequently integrated by welding. Stainless steel is used as the material of the components. When using a component created by integrally forming the casing (outer cylinder) 2 and the inlet port flange 200 as a single component using stainless steel, a high material cost results in high overall cost. In addition, processing such as machining requires great care. On the other hand, when using components that are manufactured as separate components and subsequently integrated by welding, the welding operation requires great care, and despite no longer having to perform processing such as machining, cost reduction cannot be achieved. In addition, using stainless steel in the casing (outer cylinder) 2 increases weight and imposes a strain during installation work at an installation site. A vacuum pump and a flange disclosed in Japanese Patent Application Laid-open No. 2008-75489 are provided with a mechanism which absorbs energy with an inlet port flange when the vacuum pump is subjected to impact. Even with the vacuum pump disclosed in Japanese Patent Application Laid-open No. 2008-75489, a casing (outer cylinder) and the inlet port flange having been integrally formed as a single component are used. Japanese Patent Application Laid-open No. 2015-59426 discloses a technique for absorbing, with a stator component, fracture energy created when a rotor breaks while rotating in a vacuum pump. Specifically, it is described that the following condition is satisfied between an outer peripheral surface and an inner peripheral surface of a casing of the vacuum pump in a state where the stator component is housed inside the casing. 2d/D ≤ εmax (D: outer diameter of stator component, d: width of gap, and εmax: elongation at break of stator component) Accordingly, when fracture energy is generated, since the elongated and deformed stator component either does not come into contact or only comes into slight contact with the inner peripheral surface of the casing, the fracture energy can be prevented from being transferred to the casing via the stator component. Other relevant prior art documents are US 7 495 173 B2, US 2009/081056 A1 and JP S60 28298 U. In a vacuum pump, since a rotor is rotating at high speed inside the vacuum pump, when some kind of problem occurs during an operation of the vacuum pump and the rotor collides with a stator member inside the vacuum pump, a large torque that causes the entire vacuum pump to rotate in a direction of rotation of the rotor is instantaneously generated. The torque also places heavy stress on a vacuum container via the inlet port flange. Therefore, the inlet port flange may sometimes be