Molecular pump and connecting device
View Patent ↗A flange of a molecular pump is connected to a vacuum vessel by first bolts that extend through elongate holes in the flange and are bolted to the vacuum vessel. One or more buffering members are attached to the flange by the first bolts that extend through first openings in the buffering members and by second bolts that extend through second openings in the buffering members and are bolted to the flange. In the event of malfunction of the molecular pump that generates an abnormally high torque, the buffering members plastically deform and absorb the shock energy caused by the abnormal torque thereby preventing damage to the vacuum vessel.
1. A molecular pump attached to a vacuum vessel for exhausting gas from the vacuum vessel, comprising:
a casing having a stator and provided with an inlet and an outlet;
a rotor rotatably supported in the casing and cooperating with the stator for transferring gas from the inlet to the outlet;
a motor for rotating the rotor;
a flange attachment portion connected to an end portion of the casing and having a fastening hole extending through the flange attachment portion in the thickness direction and an elongated hole extending from the fastening hole in a direction opposite to the rotation direction of the rotor;
a buffering member having a buffering portion that transforms and absorbs shock energy due to abnormal torque generated during malfunction of the molecular pump, a first fixing portion provided at one end of the buffering portion and having a fastening hole, and a second fixing portion provided at the other end of the buffering portion;
fastening means for fastening the buffering member to the vacuum vessel via the fastening hole in the flange attachment portion and the fastening hole in the buffering member; and
fixing means for fixing the second fixing portion of the buffering member to the flange attachment portion but not to the vacuum vessel.
2. The molecular pump according to claim 1 , wherein the buffering member is by comprised of a plurality of members having different stress-strain characteristics.
3. The molecular pump according to claim 1 , wherein the fastening means has a higher strength than the fixing means.
4. The molecular pump according to claim 2 , wherein the fastening means has a higher strength than the fixing means.
5. The molecular pump according to claim 1 , wherein the fixing means is arranged on the side opposite to the side on which the elongated hole is formed with respect to the fastening means.
6. The molecular pump according to claim 2 , wherein the fixing means is arranged on the side opposite to the side on which the elongated hole is formed with respect to the fastening means.
7. The molecular pump according to claim 3 , wherein the fixing means is arranged on the side opposite to the side on which the elongated hole is formed with respect to the fastening means.
8. The molecular pump according to claim 4 , wherein the fixing means is arranged on the side opposite to the side on which the elongated hole is formed with respect to the fastening means.
9. The molecular pump according to claim 1 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
10. The molecular pump according to claim 2 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
11. The molecular pump according to claim 3 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
12. The molecular pump according to claim 4 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
13. The molecular pump according to claim 5 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
14. The molecular pump according to claim 6 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
15. The molecular pump according to claim 7 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
16. The molecular pump according to claim 8 , wherein at least one of the fastening means and the fixing means comprises a bolt having a head at the terminal end thereof, and
the fixing portion of the buffering member which is in contact with the head of the bolt contacts the bolt over the whole circumference of the head of the bolt.
17. A connecting device for connecting a first vessel and a second vessel, at least one of which incorporates a rotator, to each other, comprising:
a flange connected to the first vessel and having a fastening hole extending therethrough in the thickness direction and an elongated hole extending from the fastening hole in the direction such that the second vessel moves relatively when being subjected to a shock due to abnormal torque in the rotation direction of the rotator during malfunction of the rotator;
a buffering member having a buffering portion that transforms and absorbs shock energy when the second vessel moves relatively, a first fixing portion provided at one end of the buffering portion and having a fastening hole, and a second fixing portion provided at the other end of the buffering portion;
fastening means for fastening the buffering member to the second vessel via the fastening hole in the flange and the fastening hole in the buffering member; and
fixing means for fixing the second fixing portion of the buffering member to the flange but not to the second vessel.
18. The connecting device according to claim 17 , wherein the buffering member is comprised of a plurality of members having different stress-strain characteristics.
19. The connecting device according to claim 17 , wherein the fastening means has a higher strength than the fixing means.
20. The connecting device according to claim 18 , wherein the fastening means has a higher strength than the fixing means.