Power source-integrated vacuum pump

A power source-integrated vacuum pump in which a pump main body including a pump rotor and a pump power source configured to supply power to the pump main body are integrated together, comprises: a pump housing configured to house the pump rotor; a power source housing of the pump power source, the power source housing being fixed to the pump housing; a heat transfer member provided at a fixing portion between the pump housing and the power source housing in contact with the pump housing and the power source housing; and a sealing member provided at the fixing portion between the pump housing and the power source housing to seal between the pump housing and the power source housing.

TECHNICAL FIELD

The present invention relates to a power source-integrated vacuum pump.

BACKGROUND ART

A turbo-molecular pump configured to exhaust gas in such a manner that a rotor provided with rotor blades is rotatably driven by a motor and the rotor blades are rotated relative to stationary blades at high speed has been known as a vacuum pump used for a semiconductor manufacturing device etc. A turbo-molecular pump configured such that a pump main body and a control device integrated together are cooled by a cooling fan has been known as the above-described turbo-molecular pump (see, e.g., Patent Literature 1 (JP-A-2013-100760)).

The turbo-molecular pump described in Patent Literature 1 is configured such that a clearance is formed between a base of the pump main body and a housing of the control device and that the control device is cooled by cooling air sent to the clearance.

However, not only a power source cable but also cables for a temperature sensor and a brake resistor provided on a pump main body side are, between the pump main body and the control device, connected to the control device. Thus, the multiple cables are interposed between the pump main body and the control device, and openings for insertion of the multiple cables need to be formed at the housing of the control device. As a result, it is difficult to prevent external moisture air from entering the housing of the control device, and damage of the control device due to moisture air entrance might be caused.

SUMMARY OF THE INVENTION

A power source-integrated vacuum pump in which a pump main body including a pump rotor and a pump power source configured to supply power to the pump main body are integrated together, comprises: a pump housing configured to house the pump rotor; a power source housing of the pump power source, the power source housing being fixed to the pump housing; a heat transfer member provided at a fixing portion between the pump housing and the power source housing in contact with the pump housing and the power source housing; and a sealing member provided at the fixing portion between the pump housing and the power source housing to seal between the pump housing and the power source housing.

The power source-integrated vacuum pump further comprises: a cooling fan configured to send cooling air to the pump housing.

A heat sink is provided in a region of the pump housing to which the cooling air is sent.

The power source housing has a housing wall portion fixed to at least some of multiple electric components provided at the pump power source and contacting the heat transfer member.

The housing wall portion includes a refrigerant path for circulating liquid refrigerant.

A coefficient of thermal conductivity of the heat transfer member is equal to or higher than those of the pump housing and the power source housing.

The heat transfer member also serves as the sealing member.

According to the present invention, radiation performance of a power source can be ensured while external air entrance into the power source can be prevented.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.FIG. 1is a view of a schematic configuration of a power source-integrated vacuum pump of the present embodiment. The vacuum pump1is a magnetic bearing turbo-molecular pump, and is configured such that a pump unit20and a power source30are fixed with bolts40as illustrated inFIG. 1.

In the pump unit20, a shaft3attached to a rotor2is non-contact supported by electromagnets51,52provided at a pump base4. The levitation position of the shaft3is detected by a radial displacement sensor71and an axial displacement sensor72provided at the pump base4. The electromagnets51forming radial magnetic bearings, the electromagnets52forming axial magnetic bearings, and the displacement sensors71,72form a five-axis control magnetic bearing. Note that when the magnetic bearings are not in operation, the shaft3is supported by mechanical bearings27,28.

A circular rotor disc41is provided at a lower end of the shaft3, and the electromagnets52are provided to sandwich the rotor disc41in an upper-to-lower direction through a clearance. The electromagnets52attract the rotor disc41, thereby levitating the shaft3in an axial direction. The rotor disc41is fixed to a lower end portion of the shaft3with a nut member42.

The rotor2is provided with a plurality of rotor blades8in a rotation axial direction. Each stationary blade9is arranged between adjacent ones of the rotor blades8arranged in the upper-to-lower direction. The rotor blades8and the stationary blades9form a turbine blade stage of the pump unit20. Each stationary blade9is held with the each stationary blade9being sandwiched between adjacent ones of spacers10in the upper-to-lower direction. The spacers10have the function of holding the stationary blades9, as well as having the function of maintaining a gap between adjacent ones of the stationary blades9at a predetermined interval.

A screw stator11forming a drag pump stage is provided at a later stage (the lower side as viewed in the figure) of the stationary blades9, and a gap is formed between an inner peripheral surface of the screw stator11and a cylindrical portion12of the rotor2. The rotor2and the stationary blades9held by the spacers10are housed in a pump case13provided with a suction port13a. When the shaft3attached to the rotor2is rotatably driven by a motor6while being non-contact supported by the electromagnets51,52, gas is exhausted from the suction port13atoward a back pressure side. The gas exhausted to the back pressure side is discharged by an auxiliary pump (not shown) connected to an exhaust port26.

The power source30is, with bolts, fixed to a bottom side of the pump base4provided at the pump unit20. The power source30configured to drivably control the pump unit20includes electric components forming a main control section, a magnetic bearing drive control section, a motor drive control section, etc. These electric components are housed in a housing of the power source30. A top panel302forming a portion of the power source housing of the power source30is provided with an opening302a. A plug324of a power source cable323provided on a power source side is, through the opening302a, connected to a receptacle411provided on a bottom surface of the pump base4. In this manner, the power source cable323is connected to the pump unit20.

A cooling fan34is provided at the side of the pump unit20. In an example illustrated inFIG. 1, the cooling fan34is fixed to a side surface of the top panel302. As indicated by a dashed line, leftward cooling air formed by the cooling fan34as viewed in the figure is blown onto the pump base4, thereby cooling the pump unit20.

FIG. 2is a plan view of the power source30from the pump unit20. The shape of the power source30as viewed in the plane is a regular octagonal shape, and the regular octagonal top panel302is fixed to a power source case301with bolts327. In an example illustrated inFIG. 2, the shape of the opening302aformed at the top panel302is a substantially rectangular shape. The top panel302is provided with screw holes328for fixing the power source30to the pump base4with the bolts40(seeFIG. 1).

The plug324of the power source cable323is drawn from the opening302a, and then, is connected to the receptacle411provided on the bottom surface of the pump base4(seeFIG. 1). Similarly, a temperature sensor cable325and a brake heater cable326are drawn from the opening302a, and then, are connected to a temperature sensor (not shown) and a brake heater (not shown) provided on a pump unit side. Thus, the opening302ais largely formed to the extent that drawing of each cable is not interfered. In a case where the attachment positions of the receptacle411, the temperature sensor, and the brake heater at the pump base4are significantly different from each other, openings for drawing the power source cable323, the temperature sensor cable325, and the brake heater cable326need to be formed corresponding to each position.

FIG. 3is a view for describing a structure of a fixing portion between the power source30and the pump unit20of the vacuum pump1illustrated inFIG. 1. The power source30includes the power source case301as the power source housing and the top panel302. A member (e.g., aluminum alloy) having a relatively-high coefficient of thermal conductivity is used as the materials of the power source case301and the top panel302. The electric components of the power source30are housed in this power source housing. In an example illustrated inFIG. 3, an electric component321with a relatively-great amount of heat generation is mounted on a circuit board311fixed to the top panel302. On the other hand, an electric component322with a relatively-small amount of heat generation is mounted on a circuit board313fixed to the power source case301. The circuit board313is fixed to the power source case301through a support rod312.

An O-ring seal304as a sealing member is provided between the power source case301and the top panel302, the power source case301and the top panel302being fixed together. The top panel302is, with the bolts40, fixed to a base flange400provided at the pump base4. A heat transfer member402and an O-ring seal401as a sealing member are provided between the top panel302and the base flange400. The O-ring seal401can prevent external air from entering the power source housing through a fixing portion between the pump base4and the top panel302. As a result, damage of the power source30due to moist air entrance into the power source housing from external environment is prevented.

A member (e.g., metal) having a relatively-high coefficient of thermal conductivity is used for the heat transfer member402. Preferably, a member having a thermal conductivity coefficient equal to or higher than those of members used for the power source housing (the power source case and the top panel302) and the pump base4may be used. For example, aluminum-based or copper-based metal is used. Note that in the example illustrated inFIG. 3, a ring-shaped metal plate is used as the heat transfer member402, but the heat transfer member402is not necessarily in the ring shape. Such a heat transfer member402is arranged at the fixing portion in contact with the pump base4and the top panel302, and therefore, heat of the power source30can be effectively transferred to the pump base4.

Heat generated at the electric components is mainly transferred to the top panel302and the power source case301, and then, is transferred to the pump base4of the pump unit20through the heat transfer member402as indicated by a dashed arrow H. Eventually, the heat is released to the air. The circuit board311on which the electric component321is mounted is fixed to the top panel302contacting the heat transfer member402, and therefore, the efficiency of cooling the electric component mounted on the circuit board311can be improved. Thus, an electric component with a great amount of heat generation is preferably arranged on the top panel302. Note that radiation from the pump base4to the air may be natural radiation, but in the example illustrated inFIG. 1, forced air cooling is performed using the cooling air from the cooling fan34.

(C1) In the above-described embodiment, the vacuum pump1is the vacuum pump configured such that the pump unit20and the power source30are integrated together. The multiple cables323,325,326interposed between the pump base4as a pump housing and the top panel302as the power source housing connect the pump unit20and the power source30together through the opening302aformed at the top panel302. Further, the heat transfer member402is provided in contact with the pump base4and the top panel302at the fixing portion between the pump base4and the top panel302, and the O-ring seal401as the sealing member configured to seal a clearance between the pump base4and the top panel302is provided at the fixing portion.

Thus, according to the present embodiment, radiation performance of the power source30can be ensured while moisture air entrance into the power source30from the external environment can be prevented. As a result, damage of the power source30due to moisture air entrance can be prevented.

(C2) Further, the cooling fan34is provided as illustrated inFIG. 1to perform forced air cooling of the pump base4by means of the cooling air. Thus, the efficiency of cooling the pump unit20can be improved. Note that in the configuration illustrated inFIG. 1, the cooling air of the cooling fan34is sent to the pump base4as the pump housing. However, the cooling fan34may be shifted to a base side such that the cooling air is sent to both of the pump base4and the power source housing (the power source case301and the top panel302).

The following variations fall within the scope of the present invention, and one or more of the variations may be combined with the above-described embodiment.

FIG. 4is a view of a first variation of the above-described embodiment. In the embodiment illustrated inFIG. 3, the O-ring seal401as the sealing member and the heat transfer member402are provided between the pump base4and the top panel302. However, in the first variation, only a heat transfer member403exhibiting sealability is arranged. Easily plastic deformable metal foil (e.g., copper foil), thinly-applied thermal grease (e.g., a base material, such as silicone, containing a metal component) on a metal plate, thermal silicone, etc. is used as the heat transfer member403. For example, in the case of using the copper foil, the coefficient of thermal conductivity of the heat transfer member403can be equal to or higher than that of the member used for the pump base4or the power source housing.

Even when the heat transfer member403also has the function of the sealing member as described above, normal-pressure external air entrance into the normal-pressure power source housing can be sufficiently prevented, and damage of the power source30due to moisture air entrance into the power source housing can be prevented.

FIG. 5is a view of a second variation of the above-described embodiment. In the second variation, radiation fins201are, in addition to the configuration of the above-described embodiment (see, e.g.,FIGS. 1 and 3), provided on an outer peripheral surface of the pump base4. The cooling air is sent from the cooling fan34to the radiation fins201. As a result, radiation performance of the pump base4can be further improved, and the temperatures of the pump unit20and the power source30can be held lower than those of the above-described embodiment.

InFIG. 5, the radiation fins201are directly formed on the outer peripheral surface of the pump base4, but a separate heat sink with radiation fins may be attached to the outer peripheral surface of the pump base4. Note that the configuration of providing the radiation fins201on the outer peripheral surface of the pump base4can be also applied to the first variation illustrated inFIG. 4, and similar advantageous effects can be provided.

FIG. 6is a view of a third variation of the above-described embodiment. In the third variation, it is configured such that an upper end of the power source case301is fixed to the pump base4with the bolts40and heat of the power source30is transferred from the power source case301to the pump base4of the pump unit20through the heat transfer member402. The top panel302provided with the opening302ais attached to the power source case301. Heat of the top panel302is transferred to the pump base4through the power source case301and the heat transfer member402.

FIG. 7is a view of a fourth variation of the above-described embodiment.FIG. 7is a plan view of a top panel303. The top panel303is used instead of the top panel302ofFIG. 2. The top panel303includes a refrigerant path330for circulating liquid refrigerant such as coolant water, and other configurations are similar to those of the top panel302illustrated inFIG. 2. Through-holes indicated by a reference numeral “329” are bolt holes into which the bolts327ofFIG. 2are inserted. In an example illustrated inFIG. 7, the refrigerant path330is formed in such a manner that a metal pipe such as a copper pipe is casted into the top panel302. An inlet portion330aand an outlet portion330bof the metal pipe protrude from the left side surface of the top panel303as viewed in the figure.

Note that in the case of the fourth variation, the top panel303is cooled by the liquid refrigerant, and therefore, heat of the pump base4is transferred to the top panel303through the heat transfer member402. The heat transferred from the pump base4and the power source case301to the top panel303is released to the liquid refrigerant flowing through the refrigerant path330.

FIG. 8is a view of a fifth variation of the above-described embodiment. In the above-described embodiment, the heat transfer member is interposed between the base flange400of the pump base4and the power source housing (the top panel302or the power source case301). In the fifth variation illustrated inFIG. 8, a heat transfer member404is fixed with bolts405in contact with side surfaces of the base flange400and the top panel303as the fixing portion between the pump housing and the power source housing. Since the heat transfer member404is provided on the side surfaces of the base flange400and the top panel303as described above, attachment, detachment, or replacement of the heat transfer member404can be facilitated. Moreover, the heat transfer member404is provided in an exposed state at the side of the base flange400and the top panel303. Thus, radiation fins may be formed at the heat transfer member404itself, thereby actively releasing heat from the heat transfer member404to the air.

The embodiment and the variations have been described above, but the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention. For example, the present invention is also applicable to other power source-integrated vacuum pumps than the turbo-molecular pump.