WO2010064588A1

WO2010064588A1 - Vacuum pump

Info

Publication number: WO2010064588A1
Application number: PCT/JP2009/070070
Authority: WO
Inventors: 大須賀透; 中澤敏治; 大山敦; 飯島直樹
Original assignee: 株式会社荏原製作所
Priority date: 2008-12-02
Filing date: 2009-11-20
Publication date: 2010-06-10
Also published as: JP5305870B2; JP2010133290A

Abstract

The vacuum pump is compact with a direct-current motor capacity of 2 KW or lower and is capable of attaining a vacuum easily at any location. The vacuum pump is equipped with a positive displacement pump (P) having a pair of pump rotors (35) inside a pump casing (33); a direct-current motor (M) for turning the pair of pump rotors (35); a driver (7) and a control unit for driving the direct-current motor (M); and cooling sections (12, 14) for air-cooling of the heat of compression which is generated by the pumping action when the pump (P) is driven and the heat generated by the direct-current motor (M), the driver (7) and the control unit.

Description

Vacuum pump

The present invention relates to a positive displacement vacuum pump provided with a pair of pump rotors driven by a DC motor in a pump casing.

In recent years, dry vacuum pumps that can operate from atmospheric pressure and can easily obtain a clean vacuum environment have been used in a wide range of fields. Normally, such a vacuum pump is operated in a state where the intake side is close to the deadline, and therefore consumes power to maintain the differential pressure between the intake port side and the exhaust port side. In other words, the degree of vacuum on the intake port side is maintained by continuing to exhaust the gas that flows back into the pump from the exhaust port side. For this reason, most of the power consumption used for the operation of the vacuum pump is converted into heat at the exhaust port side. Although depending on the capacity of the vacuum pump, conventionally, a countermeasure has been taken against the above heat generation in which a water cooling jacket or the like is provided in the casing and heat is radiated to the water passing through the water cooling jacket (Japanese Patent Laid-Open No. 8-319967). See the official gazette).
For example, as a vacuum pump, as shown in FIG. 11, a power supply unit 1 including a circuit breaker 2, a noise filter 3, a rectifier 4, a smoothing capacitor 5, and a DC / DC converter 6, a driver 7, and a DC motor M The thing provided with the vacuum pump main body provided with the pump P is known. In this vacuum pump, when the breaker 2 is turned on (closed), the AC power of the AC power supply (AC 100 V / 200 V) 8 is removed through the noise filter 3, and the AC is converted to DC (DC 141 V / 248 V) by the rectifier 4. Further, the voltage is converted to a constant voltage by the DC / DC converter 6 and power is supplied to the driver 7. The driver 7 supplies a pulse having a predetermined frequency to the DC motor M of the vacuum pump body 10 under the control of a control unit (not shown) to start the DC motor M, thereby driving the pump P.
The noise filter 3, the rectifier 4, the smoothing capacitor 5, the DC / DC converter 6, the driver 7, and the control unit have heating units, and the heat generated by the vacuum pump operation, including the heat from these heating units, is mainly Heat is dissipated by water cooling.

Cooling the vacuum pump with water cooling requires cooling water equipment to obtain cooling water, which not only increases the burden on the user, but also limits the place where the vacuum pump can be used, making it easy in any location There is a problem that a vacuum cannot be obtained.
The present invention has been made in view of the above points, and does not require a cooling water facility, and can easily obtain a vacuum at an arbitrary place with a small pumping speed of 2000 L / min or less and a DC motor capacity of 2 KW or less. An object of the present invention is to provide a vacuum pump.
In order to solve the above-described problems, a vacuum pump according to the present invention includes a positive displacement pump having a pair of pump rotors in a pump casing, a direct current motor that rotationally drives the pair of pump rotors, and the direct current motor. A driver and a control unit, and a cooling unit that cools the compression heat generated by the pump action by the operation of the pump and the heat generated from the DC motor, driver, and control unit by air cooling.
In a preferred aspect of the present invention, the direct current motor is a magnet coupling type DC brushless motor including a pair of magnet rotors that are reversed in synchronization with each other, and the pair of pump rotors of the pump are engaged with each other and rotated. The pair of magnet rotors of the magnet coupling type DC brushless motor are connected to the pair of pump rotors of the pump, respectively, and the pair of pump rotors does not use a timing gear. Inverted in sync with.
In a preferred aspect of the present invention, the capacity of the DC motor is 2 KW or less, and the output voltage from the power supply unit supplied to the DC motor is set to a high voltage within a range where the size of the power supply unit does not increase.
In a preferred aspect of the present invention, the power source for supplying power to the DC motor is provided with a power factor improving unit for improving the power factor.
In a preferred aspect of the present invention, a heat sink for dissipating heat is provided to dissipate at least a part of heat generated from the heat generating part of the pump, the DC motor, the driver, and the control part.
In a preferred aspect of the present invention, the heat sink for heat dissipation is mounted with the pump, a DC motor, a driver, and a controller, and a flow path plate is provided for the heat sink for heat dissipation to form an air flow path through which cooling air passes. The pump package is configured, and a fan for guiding cooling air is provided in the air flow path of the pump package.
In a preferred aspect of the present invention, the pump, the DC motor, the driver, and the control unit are arranged such that a small amount of heat generation is positioned upstream of the air flow path and a large amount of heat generation is positioned downstream. Is mounted on the heat sink for heat dissipation.
In a preferred aspect of the present invention, the pump package has a configuration in which an inlet and an outlet for cooling air leading to the air flow path are provided on a rear surface and a front surface of the pump package, and the pump package includes a plurality of the pump packages, The plurality of pump packages are arranged with their side surfaces adjacent to each other.
According to the present invention, the heat generated by the pump action and the heat generated from the DC motor, the driver, and the control unit are cooled by the cooling unit. A vacuum pump capable of easily obtaining a vacuum at a place can be provided.
As a direct current motor, a magnet coupling type DC brushless motor having a pair of magnet rotors that are reversed in synchronization with each other is used, and as a pair of pump rotors, a pump having a pair of male rotors and female rotors that rotate in mesh with each other. By using the pair of pump rotors so as to be reversed synchronously without using the timing gear, the mechanical loss is reduced and the air cooling means is suitable for cooling.
By setting the output voltage from the power supply unit supplied to the DC motor to a high voltage within the range where the size of the power supply unit does not increase, current is reduced by that amount, heat generation is reduced, and it is more suitable for cooling with air cooling means It becomes composition.
By providing a power factor improvement unit that improves the power factor in the power supply unit that supplies power to the DC motor, the peak current can be suppressed as much as the power factor is improved, so heat generation due to the peak current is reduced, and air cooling means The configuration is more suitable for cooling.
A heat sink for heat dissipation is provided, and heat generated from the heat generating portion is dissipated by the heat sink for heat dissipation, so that heat can be efficiently radiated.
A heat sink for heat dissipation is equipped with a pump, DC motor, driver, and control unit to form a pump package, and a fan that guides cooling air to the air flow path of the pump package can provide more efficient heat dissipation. .
The pump, DC motor, driver, and controller are mounted on the heat sink for heat dissipation so that the one with a small amount of heat generation is located upstream of the air flow path of the pump package and the one with a large amount of heat generation is located downstream. By doing so, the cooling air flows from a low temperature region to a high region, and heat can be radiated more efficiently.
By adopting a configuration in which the inlet and outlet of the cooling air leading to the air flow path of the pump package are provided on the rear and front surfaces of the pump package, the side surface of the pump package becomes a surface that hardly contributes to cooling, and a plurality of pump packages Even if the side surfaces are arranged adjacent to each other, the cooling efficiency is not lowered, so that a large number of pump packages can be installed in a small installation area.

1A is a plan view showing an outline of a vacuum pump according to an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along the line AA of FIG. 1A, and FIG. 1C is a left side view of FIG.
2A is a plan view showing an outline of a vacuum pump according to another embodiment of the present invention, FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A, and FIG. 2C is a left side view of FIG. 2A.
FIG. 3 is a sectional side view (corresponding to FIG. 1B) showing an outline of a vacuum pump according to still another embodiment of the present invention.
FIG. 4 is a block diagram showing a power supply unit of the vacuum pump according to the embodiment of the present invention.
FIG. 5 is a block diagram showing another power supply unit of the vacuum pump according to the embodiment of the present invention.
FIG. 6 is a block diagram showing still another power supply unit of the vacuum pump according to the embodiment of the present invention.
FIG. 7 is a graph showing the relationship of (air cooling member volume) / (cooling heat amount) / (water cooling structure volume) / (cooling heat amount) to the motor capacity in the vacuum pump.
8A is a plan sectional view showing a vacuum pump main body of the vacuum pump according to the embodiment of the present invention, FIG. 8B is a sectional view taken along line AA in FIG. 8A, and FIG. 8C is a sectional view taken along line BB in FIG. FIG. 8D shows the pump casing of FIG. 8B.
FIG. 9 is a sectional view showing a DC motor of the vacuum pump according to the embodiment of the present invention.
FIG. 10A is a plan view showing a state in which a plurality of vacuum pumps according to an embodiment of the present invention are arranged, and FIG. 10B is a front view.
FIG. 11 is a block diagram showing a power supply unit of a conventional vacuum pump.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the member which is the same or it corresponds, and the overlapping description is abbreviate | omitted.
1A is a plan view showing an outline of a vacuum pump according to an embodiment of the present invention, FIG. 1B is a cross-sectional view taken along line AA of FIG. 1A, and FIG. 1C is a left side view of FIG. As shown in FIGS. 1A to 1C, the present vacuum pump includes a heat sink 12 for heat dissipation, and a flow path plate 13 is attached to the lower surface of the heat sink 12, and between the

fins

12a and 12a of the heat sink 12 and the flow path plate. An air flow path 14 through which cooling air passes is formed between the both side bent portions 13 and the fins 12a. In FIG. 1A, when the left end of the heat sink 12 is the rear end and the right end is the front end, the power source component 15, the driver component 16, and the DC motor of the vacuum pump body 10 are arranged on the upper surface of the heat sink 12 in order from the rear end. M and pump P are mounted. An air outflow hole 18 is formed between the driver component 16 of the heat sink 12 and the DC motor M.
As described above, the power source component 15, the driver component 16, the DC motor M, and the pump P are mounted on the upper surface of the heat sink 12 to constitute the pump package 20, and the fins 12 a and fins of the heat sink 12 of the pump package 20 are configured. Air flow paths 14 are formed between 12a and between the bent portions on both sides of the flow path plate 13 and the fins 12a. When cooling air flows through the air flow path 14 from the rear end as indicated by an arrow B, the cooling air flows through the air flow path 14 and air provided between the driver component 16 and the DC motor M. It flows upward through the outflow hole 18. The heat generated in the heat generating parts of the power supply component 15 and the driver component 16 and transmitted to the main body of the heat sink 12 and the

fins

12a and 12a is efficiently radiated to the cooling air passing through the air flow path 14. In this example, the example in which the cooling air is forcibly introduced into the air flow path 14 has been described. However, the cooling air may flow through the air flow path 14 by natural convection.
2A is a plan view showing an outline of a vacuum pump according to another embodiment of the present invention, FIG. 2B is a cross-sectional view taken along line AA of FIG. 2A, and FIG. 2C is a left side view of FIG. This vacuum pump is different from the vacuum pump shown in FIG. 1 in that a fan 22 is provided at the front end of the heat sink 12 as means for introducing cooling air to the air flow path 14. By operating the fan 22, cooling air flows through the air flow path 14 as indicated by an arrow B, and passes through the air outlet hole 18 provided between the driver component 16 of the heat sink 12 and the DC motor M. It flows upward, passes through the periphery of the DC motor M and the pump P, and flows out from the air outlet 23 provided with the fan 22. In this example, the front end of the air flow path 14 is closed by the front panel 24.
FIG. 5 is a block diagram illustrating a configuration of a power supply unit of the vacuum pump illustrated in FIGS. 1A to 1C or 2A to 2C. As shown in FIG. 5, a power factor correction circuit (PFC) 25 is provided on the output side of the rectifier 4 in the power supply unit of the vacuum pump. The power supply component 15 is a component constituting the power factor correction circuit (PFC) 25, and the driver component 16 is a component constituting the driver 7. They are arranged in consideration of the current flow. In this example, the heat generation amount H ₁₅ of the heat generating portion of the power supply unit component ₁₅ is smaller than the heat generation amount H ₁₆ of the heat generating portion of the driver component 16, and may vary depending on the load condition of the pump. calorific value H ₁₆ of the heating unit is smaller than the calorific value H _M of the heat generating portion of the DC motor M, further heating value H _M of the heat generating portion of the DC motor M is smaller than the heating value H _P of the heat generating portion of the pump P (H ₁₅ <H ₁₆ <H _M <H _P ). That is, the air flow path 14 and the cooling air flow upstream are arranged with a small amount of heat generation and the downstream side with a large heat generation amount. As a result, the cooling air flows from the low temperature region to the high temperature region of the vacuum pump, and heat can be radiated more efficiently.
Since the peak current can be suppressed by improving the power factor of the input portion of the AC power supply (AC100V / 200V) 8, heat generation due to the peak current can be reduced. As a method for improving the power factor, as shown in FIG. 5, a power factor improving circuit (PFC) 25 is provided on the output side of the rectifier 4 to improve the power factor, or as shown in FIG. There is a method of improving the power factor by providing a direct current reactor (DCL) 26 on the output side.
In the power supply unit of the vacuum pump shown in FIG. 4, a boost chopper or voltage doubler rectifier 21 is provided to boost the DC voltage rectified by the rectifier 4 (DC 360 V in this case). As a result, the DC voltage supplied to the driver 7 can be increased and the current can be reduced accordingly, so that the amount of heat generated in the heat generating portion of the driver 7 and the DC motor M can be suppressed.
FIG. 3 is a sectional side view (corresponding to FIG. 1B) showing an outline of a vacuum pump according to still another embodiment of the present invention. This vacuum pump is different from the vacuum pump shown in FIGS. 2A to 2C in that the front end of the air flow path 14 is opened. Thus, when the fan 22 is operated, cooling air flows from the front end opening of the air flow path 14 as indicated by an arrow C, and the cooling efficiency is further improved.
FIG. 7 shows (air cooling member volume) / (cooling heat amount), (water cooling structure volume) with respect to the motor capacity of a vacuum pump having a volume transfer type pump having a pair of pump rotors in a pump casing driven by a DC motor. It is a graph which shows the relationship of / (cooling calorie | heat amount). In FIG. 7, a solid line A indicates (air cooling member volume) / (cooling heat amount), and a dotted line B indicates (water cooling structure volume) / (cooling heat amount). As is apparent from FIG. 7, when the motor capacity is about 2000 (W) or less, the volume with respect to the cooling heat quantity is superior to the air-cooled structure volume with respect to the air-cooled member volume. Therefore, an air cooling method is adopted as a cooling method of a vacuum pump having a capacity transfer type pump having a motor having a capacity of about 2000 (W) or less and a pair of pump rotors, and the above structure is adopted in the air cooling part. Thus, an excellent cooling effect can be exhibited.
8A is a plan sectional view showing the vacuum pump body 10, FIG. 8B is a sectional view taken along the line AA in FIG. 8A, FIG. 8C is a sectional view taken along the line BB in FIG. 8A, and FIG. It is. As shown in FIGS. 8A to 8C, the vacuum pump main body 10 includes a pump P and a DC motor M. The pump casing 33 of the pump P includes an intake port 31 and an exhaust port 32, and a rotor housing space 39 in which a pair of two-shaft pump rotors 35 are rotatably housed is formed inside the pump casing 33. Yes. The cross section of the rotor accommodating space 39 has a shape in which both sides are arc-shaped and convex portions 40 are formed at portions located between the pump rotors 35. Each pump rotor 35 disposed in the rotor accommodating space 39 is rotatably supported by

bearings

37 and 38 at both ends thereof.
The DC motor M includes a motor casing 41 attached to the end of the pump casing 33, and a motor stator 42 is disposed in the pump casing 41. A rotor storage space 44 in which the two motor rotors 43 are rotatably arranged is formed in the motor stator 42. The end of the motor rotor 43 of the DC motor M is connected to the shaft end of each pump rotor 35. As will be described in detail later, the DC motor M is a two-axis synchronous inversion drive motor in which two axes are synchronously reversed. By starting the two-axis synchronous inversion drive motor, a pair of pump rotors 35 of the pump P are driven in reverse in synchronization.
As described above, the gas in the space surrounded by the pump rotor 35 and the pump casing 33 is compressed by reversing the pair of pump rotors 35 of the pump P in synchronization with each other. The pump casing 33 is provided with the intake port 31 and the exhaust port 32 as described above, and the exhaust port 32 can exhaust the intake port to 10 ⁻³ to 10 Torr under atmospheric pressure.
FIG. 9 shows a two-axis synchronous inversion drive motor, that is, a DC motor M, that inverts a pair of pump rotors 35 of the pump P synchronously. As shown in FIG. 9, the two-axis synchronous inversion drive motor includes a pair of magnet rotors (motor rotors) 43, 43 having the same configuration, and a pair of

pump rotors

35, 35 as a brushless DC motor. The reversal drive is performed, and synchronous reversal of the

pump rotors

35 and 35 is secured by magnet coupling. As shown in FIG. 9, each magnet rotor 43 is provided with a ring-shaped magnet 43a around the outer periphery of a magnetic material yoke 43b. In this example, a magnetized magnet 43a is provided on the outer periphery of the magnet rotor 43, and is opposed to each other so that the different magnetic poles of the

magnet rotors

43 and 43 are attracted to each other and with a clearance F maintained. . The number of poles of the magnet rotor 43 is an even number such as 4, 6, 8,...
The

pump rotors

35 and 35 rotate in the opposite direction synchronously by the magnet coupling action of the

magnet rotors

43 and 43. Thus, a screw pump capable of stable two-axis synchronous reversal without a timing gear is configured. Further, the absence of the timing gear means that no lubricating oil is required, non-contact rotation including a safe biaxial synchronization mechanism is possible, and high speed operation of the screw pump is possible. That is, in the contact-type synchronization mechanism using the timing gear, the rotation speed is 6000 to 7000 min ⁻¹ , but the synchronous inversion high speed rotation of 10,000 to 30000 min ⁻¹ using the magnet coupling of the 6-

pole magnet rotors

43 and 43 is performed. Thus, even if the vacuum pump is made small, it is possible to achieve an improvement in exhaust performance such as a high ultimate vacuum.
Close to a part of the outer peripheral surface of each magnet rotor 43, a three-phase (U, V, W) motor stator 42 including an iron core 42a and a winding 42b is disposed. The three-phase motor stator 42 is disposed on the side opposite to the side where the magnet rotors 43 are coupled to each other with respect to the rotation axis. Thereby, the magnet coupling force that the magnet rotors 43 attract each other can be canceled by the attraction force that acts on the magnet rotor 43 and the iron core 42a of the motor stator. Further, the three-phase motor stator magnetic pole corresponds to the number of magnetic poles of the magnet rotor 43, and a magnetic field is applied to the four poles of the magnet rotor 43 as indicated by arrows G and H in FIG. By supplying a direct current having a required rectangular pulse waveform to the three-phase winding 42b, the pair of pump rotors 35 of two shafts can be synchronously inverted and driven at an arbitrary rotational speed.
A vacuum pump body 10 including a DC motor M, which is a magnet coupling type DC brushless motor having the above-described configuration, and a volume transfer type pump P including a pair of two-axis pump rotors 35 is illustrated in FIGS. 1A to 1C. 2A to 2C or 3, the heat sink 12 is mounted on the front end side (downstream side of the cooling air flow), and the power supply component 15 and the driver component 16 are mounted on the rear end side (cooling). By mounting on the downstream side of the air flow, the amount of heat generated from the heat generating portion of the DC motor M is small, so that sufficient cooling is possible even with air cooling. Further, as shown in FIG. 4, the power supply unit 1 is provided with a step-up chopper or voltage doubler rectifier 21 to boost the voltage supplied to the driver 7. The amount becomes smaller. Further, by providing a power factor correction circuit (PFC) 25 as shown in FIG. 5 or providing a direct current reactor (DCL) 26 as shown in FIG. 6 to improve the power factor, the peak current is suppressed. The amount of heat generated from the heat generating portion can be reduced by the peak current.
10A is a plan view showing a case where a plurality (four in the figure) of vacuum pumps VP according to the embodiment of the present invention configured as shown in FIGS. 1A to 1C are arranged, for example, FIG. 10B is a front view. It is. The inflow and discharge of the cooling air in each vacuum pump VP is performed through the inlet provided on the rear end surface (back surface) of the vacuum pump VP and the exhaust port provided on the front end surface (front surface). The surface hardly contributes to cooling. Therefore, both side surfaces of each vacuum pump VP can be arranged close to each other so as to come into contact with each other (side-by-side arrangement), and a space-saving space for installing a plurality of vacuum pumps VP can be achieved. Moreover, since each vacuum pump VP can be lightened and miniaturized so that it can be conveyed by human power, it can be easily conveyed and arranged by attaching the handle 50 to a predetermined position on the upper surface.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the technical idea described in the claims and the specification and drawings. Is possible. Note that any shape or structure not directly described in the specification and drawings is within the technical scope of the present invention as long as the effects of the present invention are achieved.

The present invention is applicable to a volume transfer type vacuum pump having a pair of pump rotors in a pump casing driven by a DC motor.

Claims

A positive displacement pump with a pair of pump rotors in the pump casing;
A DC motor that rotationally drives the pair of pump rotors;
A driver and a controller for driving the DC motor;
A vacuum pump, comprising: a cooling unit that cools, by air cooling, compression heat generated by a pumping action due to operation of the pump and heat generated from the DC motor, driver, and control unit.
The vacuum pump according to claim 1, wherein
The DC motor is a magnet coupling type DC brushless motor having a pair of magnet rotors that are reversed in synchronization with each other.
The pair of pump rotors of the pump includes a pair of male and female rotors that mesh with each other and rotate,
A pair of magnet rotors of the magnet coupling type DC brushless motor are connected to the pair of pump rotors of the pump, respectively, and the pair of pump rotors are reversed in synchronization without using a timing gear. A vacuum pump characterized by that.
The vacuum pump according to claim 1 or 2,
The capacity of the DC motor is 2 KW or less, and the output voltage from the power supply unit supplied to the DC motor is a high voltage within a range where the size of the power supply unit does not increase.
The vacuum pump according to any one of claims 1 to 3,
A vacuum pump comprising a power factor improving unit for improving a power factor in a power supply unit for supplying electric power to the DC motor.
The vacuum pump according to any one of claims 1 to 4,
A vacuum pump comprising: a heat sink for radiating heat that radiates at least part of heat generated from the heat generating part of the pump, the DC motor, the driver, and the control part.
The vacuum pump according to claim 5,
The pump, the DC motor, the driver, and the control unit are mounted on the heat sink for heat dissipation, and a flow path plate is provided on the heat sink for heat dissipation to form a pump package that forms an air flow path through which cooling air passes.
A vacuum pump comprising a fan for introducing cooling air into an air flow path of the pump casing.
The vacuum pump according to claim 6,
The pump, the DC motor, the driver, and the control unit are connected to the heat sink for heat dissipation so that the small heat generation amount is located on the upstream side of the air flow path of the pump package and the large heat generation amount is located on the downstream side. A vacuum pump characterized by being mounted on
The vacuum pump according to claim 6 or 7,
The pump package has a configuration in which an inlet and an outlet of cooling air led to the air flow path are provided on the rear surface and the front surface of the pump package,
A vacuum pump comprising a plurality of the pump packages, wherein the plurality of pump packages are arranged with their side surfaces adjacent to each other.