Splinter shield for vacuum pump, and vacuum pump with the splinter shield

Abstract

The present invention provides a splinter shield for a vacuum pump, capable of reducing costs of the splinter shield by obtaining a single sheet of splinter shield having a required strength, in which fastening strength to a fixing groove is enhanced to prevent the splinter shield from bending toward the inside of a pump and coming into contact with equipment inside the pump when air rushes into the pump through an inlet port and to prevent the splinter shield from falling. Furthermore, attachment and removal of the splinter shield with respect to the inlet port are facilitated. The present invention is a splinter shield for a vacuum pump in which a rim formed in a circumferential edge portion of the splinter shield is inserted into a fixing groove that is provided in a concave manner in an inner circumferential portion of an inlet port, and the splinter shield is provided in a tensioned manner to the inlet port by pushing a retaining ring into the fixing groove, wherein locking parts that are locked into the retaining ring at a plurality of sections in the rim are provided in a standing manner at substantially right angles to the rim.

Claims

1. A splinter shield for a vacuum pump in which a rim formed in a circumferential edge portion of the splinter shield is inserted into a fixing groove that is provided in a concave manner in an inner circumferential portion of an inlet port of the vacuum pump, and the splinter shield is provided in a tensioned manner to the inlet port by pushing a retaining ring into the fixing groove, wherein said splinter shield is made of metal, and, locking parts that are locked into the retaining ring are formed at intervals along the rim and are provided in a standing manner at substantially right angles to the rim, said locking parts are formed before inserting said splinter shield into said fixing groove, a space is provided between the fixing groove and a top of the locking parts, and the locking parts are pushed to and fastened to an inner peripheral wall of the fixing groove by an opening tendency of the retaining ring.

2. The splinter shield for a vacuum pump according to claim 1, comprising a wire netting portion and a rib portion for reinforcement disposed as a crosspiece within the rim, wherein the wire netting portion and the rib portion are integrally formed with a single sheet member.

3. A vacuum pump, comprising the splinter shield for a vacuum pump according to claim 1 or 2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a vertical cross-sectional diagram of a vacuum pump shown as an embodiment of the present invention;

(2) FIG. 2 is a plan view of a splinter shield that is applied to a splinter shield for a vacuum pump according to the embodiment of the present invention;

(3) FIG. 3 is an enlarged view of locking parts of the splinter shield shown in FIG. 2, wherein FIG. 3A is a perspective view showing the locking parts from the front and FIG. 3B is a perspective view showing the locking parts from the side;

(4) FIG. 4 is a plan view of a retaining ring used for fastening the splinter shield of FIG. 2 to an inlet port;

(5) FIG. 5 is a traverse cross-sectional diagram partially showing a structure in which the splinter shield shown in FIG. 2 is fixed to the inlet port;

(6) FIG. 6 is a plan view of a wire net according to the second conventional technology;

(7) FIG. 7 is a plan view of a reinforcing plate according to the same conventional technology;

(8) FIG. 8 is a diagram showing a structure in which the splinter shield is fixed to the inlet port according to the same conventional technology, wherein FIG. 8A is a traverse cross-sectional diagram showing the entire structure and FIG. 8B is a traverse cross-sectional diagram showing the enlargement of a section where the splinter shield is fastened to a fixing groove shown in FIG. 8A; and

(9) FIG. 9 is a traverse cross-sectional diagram showing the section where the splinter shield is fastened to the fixing groove according to the second conventional technology.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

(10) In order to accomplish the object of reducing costs of a splinter shield by obtaining a single sheet of splinter shield having a required strength and enhanced fastening strength to a fixing groove, preventing the splinter shield from bending toward the inside of a pump and coming into contact with equipment inside the pump when air rushes into the pump through an inlet port, so that the splinter shield does not fall, and facilitating attachment and removal of the splinter shield with respect to the inlet port, the present invention realizes a splinter shield for a vacuum pump in which a rim formed in a circumferential edge portion of the splinter shield is inserted into a fixing groove that is provided in a concave manner in an inner circumferential portion of an inlet port of the vacuum pump, and the splinter shield is provided in a tensioned manner to the inlet port by pushing a retaining ring into the fixing groove, wherein locking parts that are locked into the retaining ring at a plurality of sections in the rim are provided in a standing manner at substantially right angles to the rim.

Embodiment 1

(11) A preferred embodiment of the present invention is described hereinafter with reference to FIGS. 2 to 5. Note that, in FIGS. 4 and 5, the same reference numerals are applied to the components same as or equivalent to those shown in FIGS. 8A and 8B, and hence the overlapping description is omitted accordingly.

(12) FIG. 1 is a vertical cross-sectional diagram of a vacuum pump according to the present invention.

(13) In FIG. 1, a vacuum pump 100 is provided with a housing 130 having an inlet port 110 and an exhaust port 120. The inside of the housing 130 is provided with a turbomolecular pump part 140 at an upper part, a cylindrical thread groove pump part 150 at a lower part, and an exhaust path 240 that passes through the turbomolecular pump part 140 and the thread groove pump part 150 to connect the inlet port 110 and the exhaust port 120 with each other.

(14) More specifically, the exhaust path 240 alternately connects the gap between an outer circumferential surface of an after-mentioned rotor 170 of the turbomolecular pump part 140 and an inner circumferential surface of the housing 130 that face each other and the gap between an outer circumferential surface of an after-mentioned cylinder rotor 210 of the thread groove pump part 150 and an inner circumferential surface of a stator 230, connects a gap upper end on the turbomolecular pump part 140 side to the inlet port 110, and connects a gap lower end on the thread groove pump part 150 side to the exhaust port 120.

(15) The turbomolecular pump 140 is configured by combining a plurality of rotary vanes 180, which are provided in a protruding manner on the outer circumferential surface of the aluminum alloy rotor 170 fixedly provided to a rotating shaft 160, and a plurality of stationary vanes 190, which are provided in a protruding manner on the inner circumferential surface of the housing 130.

(16) The thread groove pump part 150 is configured by the cylinder rotor 210 and the stator 230. The cylinder rotor 210 is located at a lower end part of the rotor 170 in the turbomolecular pump part 140. The stator 230 faces the outer circumference of the cylinder rotor 210, with a small gap therebetween, and is installed with a thread groove 220 that forms a part of the exhaust path 240 along with the small gap. The thread groove 220 is formed so as to become gradually shallower toward the bottom. The stator 230 is fixed to an inner surface of the housing 130. A lower end of the thread groove 220 is connected to the exhaust port 120 on the lowermost stream side of the exhaust path 240.

(17) A motor rotor 260a of a high-frequency motor 260, such as an induction motor, provided inside a motor housing 250, is fixed to a middle part of the rotating shaft 160. The rotating shaft 160 is supported by a magnetic bearing and provided with upper and lower protective bearings 270.

(18) Operations of the vacuum pump shown in FIG. 1 are described next. Gas that flows in through the inlet port 110 as a result of driving the high-frequency motor 260 is in a molecular flow state or an interflow state similar thereto. The actions of the rotating rotary vanes 180 of the turbomolecular pump part 140 and the stationary vanes 190 protruding from the housing 130 apply a downward momentum to gas molecules of the gas, whereby the gas is moved toward the downstream side while being compressed by the high-speed rotation of the rotary vanes 180.

(19) The gas that moves while being compressed is guided by the rotating cylinder rotor 210 and the thread groove 220 in the thread groove pump part 150, the thread groove 220 forming the small gap together with the stator 230 and becoming gradually shallow toward a downstream of the stator 230. The gas then flows through the exhaust path 240 while being compressed into a viscous flow state, and is then discharged from the exhaust port 120.

(20) A configuration of a splinter shield for a vacuum pump according to the present embodiment is described next. In FIGS. 2 to 4, a splinter shield 12 of the present embodiment is formed as a single piece of sheet by etching a single metal plate, wherein a wire netting portion 12b having a rim 12a in its circumferential edge portion and a cross-shaped rib portion 12c for reinforcement disposed as a crosspiece within the rim 12a are integrated. The wire netting portion 12b is perforated with a plurality of hexagonal holes in the form of, for example, a honeycomb.

(21) Locking parts 12d that are locked into an after-mentioned retaining ring are provided in a plurality of sections in the rim 12a so as to stand in a standing manner at substantially right angles to the rim 12a, as shown in FIGS. 3A and 3B. The locking parts 12d are formed by forming projections that protrude outward from the rim 12a and then folding the projections at substantially right angles to the rim 12a at the time of the etching process described above. As shown in FIG. 2, four pairs of the locking parts 12d are formed at equal intervals in a circumferential edge portion of the splinter shield 12.

(22) FIG. 4 shows a retaining ring 8. A part of the retaining ring 8 is cut out into a notch 8a, and an appropriate size of gap is formed therein.

(23) Fixing the splinter shield for a vacuum pump having the above-described configuration to the inlet port and operations of the splinter shield are described next with reference to FIG. 5. An outer edge of the rim 12a is provided with the locking parts 12d that stand in a standing manner at substantially right angles to the rim 12a. This rim 12a is inserted into a fixing groove 7 that is provided in a concave manner in an inner circumferential portion of the inlet port 4, and subsequently the retaining ring 8 is pushed into this fixing groove 7.

(24) In so doing, the retaining ring 8 is pushed into the fixing groove 7 such that the gap formed in the notch 8a becomes narrow, resulting in an opening tendency. This opening tendency acts to further push the locking parts 12d, whereby the rim 12a with the locking parts 12d is strongly fastened to the fixing groove 7. The splinter shield 12 is fixed to the inlet port 4 by this aspect of fastening the rim 12a having the locking parts 12d to the fixing groove 7.

(25) Furthermore, the strength of the splinter shield 12 itself is enhanced by integrally forming the wire netting portion 12b and the rib portion 12c for reinforcement in the splinter shield 12. Consequently, the splinter shield 12 can sufficiently be prevented from bending toward the inside of the pump and falling when air rushes into the pump through the inlet port 4.

(26) As described above, four pairs of the locking parts 12d are formed at equal intervals in the circumferential edge portion of the splinter shield 12. These four pairs of locking parts 12d are pushed into and fastened to the fixing groove 7 by the retaining ring 8. In addition, the locking parts 12d are pushed into and fastened to the fixing groove 7 by the retaining ring 8, instead of pushing the locking parts 12d into the fixing groove 7 and the tightly coupling and fastening the locking parts 12d to the fixing groove 7. Therefore, the splinter shield 12 can easily be attached to or removed from the inlet port 4 by simple attachment or removal of the retaining ring 8.

(27) As described above, in the splinter shield for a vacuum pump according to the present embodiment and the vacuum pump having such splinter shield, the splinter shield 12 is obtained as a single piece of sheet by integrally forming the wire netting portion 12b and the cross-shaped rib portion 12c for reinforcement, instead of obtaining a composite part in which a wire net and reinforcing plate are formed separately and superposed on each other. Thus, the splinter shield 12 has a required strength, and the costs thereof can be reduced.

(28) The fastening strength of the splinter shield 12 to the fixing groove 7 can be enhanced sufficiently. As a result, the splinter shield 12 can be prevented from bending toward the inside of the pump and coming into contact with the equipment inside the pump such as the rotary vanes when air rushes into the pump through the inlet port 4. As a result, damage to the pump can be prevented, and the splinter shield 12 can be prevented from falling.

(29) Because the present invention is not configured to push the locking parts 12d into the fixing groove 7 to tightly couple the locking parts 12d and the fixing groove 7 to each other, the locking parts 12d being provided in a standing manner at substantially right angles to the rim 12a, the splinter shield 12 can easily be attached to and removed from the inlet port 4.

(30) Note that various modifications can be made to the present invention without departing from the spirit of the present invention, and it should be clearly understood that the present invention is intended to encompass such modifications.

INDUSTRIAL APPLICABILITY

(31) The present invention can be applied widely to all types of gas intake mechanisms that need to be able to reduce costs of a splinter shield by obtaining a single sheet of splinter shield having a required strength and enhanced fastening strength to a fixing groove, to prevent the splinter shield from bending toward the inside of a gas intake mechanism and coming into contact with equipment inside the gas intake mechanism when air rushes into the gas intake mechanism through an inlet port, so that the splinter shield does not fall, and to facilitate attachment and removal of the splinter shield with respect to the inlet port.