Patent attributes
To provide a vacuum pump which separates and constructs an inlet port flange and a casing (outer cylinder) as two components to reduce weight while retaining required strength and which is consequently capable of reducing manufacturing cost. In a vacuum pump, an inlet port flange and a casing (outer cylinder) are separated from each other and constructed as different members. The inlet port flange uses stainless steel as a material thereof and the casing (outer cylinder) use aluminum as a material thereof. The components are fastened to each other by bolts and sealed by an O-ring in order to maintain a vacuum property during assembly of the vacuum pump. Accordingly, a weight of the vacuum pump can be reduced while maintaining strength of the inlet port flange.