JPH11311192A - Multistage root pump and multistage pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure easiness of installation with a compact foot space while implementing reduction of production cost. SOLUTION: First to third rotors composed of a set of three or more pieces of odd number are used. In a casing, suction ports 2b, 2e of a foremost stage pump chamber 2a is opened, discharge ports 2d, 3d, 4d, 2c, 3c, 4c of forward stage pump chambers 3a, 4a as well as the foremost stage pump chamber 2a are sequentially connected to suction ports 3e, 4e, 5e, 3b, 4b, 5b of rear stage pump chambers 3a, 4a, 5a, and discharge ports 5b, 5c of a rearmost stage pump chamber 6a are opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-stage roots pump which is driven by a rotary driving device such as a motor and performs a pumping operation sequentially in each stage of a pump chamber, and a multi-stage rooting pump integrally having the rotary driving device and the multi-stage roots pump. The present invention relates to a pump device.

[0002]

2. Description of the Related Art In a commercially available multi-stage pump device, a multi-stage roots pump is integrated with a motor. Here, in the multi-stage roots pump, a plurality of pump chambers each having an intake port and an exhaust port are formed in parallel in a casing. A set of two rotors is arranged in each pump chamber. Each rotor is mounted on two shafts parallel to each other and rotates while meshing with each other. In the casing, an intake port of the foremost pump chamber is opened.
In addition, a partition having a relatively long axial length is formed between the pump chamber of the former stage and the pump chamber of the latter stage, and the exhaust port of the pump chamber of the former stage circulates about 180 ° in the partition while the pump of the latter stage is formed. It is sequentially connected to the air inlet of the room. The exhaust port of the last pump chamber is open. A drive shaft that protrudes from the drive main body of the motor and is rotationally driven is connected to one of the shafts of the multi-stage roots pump. A drive gear is fixed to the tip of one shaft of the multi-stage roots pump connected to the drive shaft of the motor, and this drive gear is meshed with a driven gear fixed to the tip of the other shaft of the multi-stage roots pump. It is designed to transmit rotation.

When it is desired to evacuate a certain room using such a multi-stage pump device to form a decompression chamber, for example, in a multi-stage roots pump, the suction port of the foremost stage pump room is opened into the room and the last stage pump room is opened. The exhaust port of the pump chamber is opened to the atmosphere or the like. Then, the multi-stage roots pump is driven by the motor. As a result, the respective rotors mesh with each other and rotate in the respective pump chambers of the multi-stage roots pump, so that the pumping action is sequentially performed in the respective pump chambers, and the air in the chamber is released to the atmosphere or the like to make the chamber a decompression chamber. It becomes possible.

[0004]

However, in the above-mentioned conventional multi-stage roots pump or multi-stage pump device, the upstream pump chamber is used as a means for sequentially connecting the exhaust port of the upstream pump chamber and the intake port of the downstream pump chamber. A communication path that rotates substantially 180 ° is formed in a partition wall formed between the pump chamber and the downstream pump chamber. For this reason, a partition having a relatively long shaft length must be formed, and the shaft length of the multi-stage roots pump or the multi-stage pump device itself becomes longer, which leads to an increase in installation space (foot space), thereby causing difficulty in installation. Resulting in.

Of course, as disclosed in Japanese Patent Application Laid-Open No. Hei 4-8891, it is conceivable to sequentially connect the exhaust port of the upstream pump chamber and the intake port of the downstream pump chamber with an external pipe or the like. In this case, piping and the like are troublesome, which leads to an increase in manufacturing cost. The present invention has been made in view of the above-described conventional situation, and provides a multi-stage roots pump or a multi-stage pump device capable of securing the ease of installation by reducing the foot space while realizing a low manufacturing cost. Is to solve the problem.

[0006]

SUMMARY OF THE INVENTION A multi-stage roots pump according to the present invention is provided with a casing having a plurality of pump chambers each having an intake port and an exhaust port, each of which is arranged in parallel with each other, and arranged in each of the pump chambers and in parallel with each other. A plurality of rotors mounted on a plurality of shafts and rotating by meshing with each other, wherein the rotor comprises a set of three or more rotors, and in the casing, the suction of the pump chamber at the forefront stage is performed. The outlet is opened, and the exhaust port of the preceding pump chamber is sequentially connected to the intake port of the subsequent pump chamber on the same side with respect to an imaginary plane including the axes of the plurality of shafts, and the last pump The exhaust port of the chamber is opened.

[0007] If three or more multi-stage roots pumps constitute a set of rotors, the same stage pump chamber can be used.
Two or more inlets and outlets will be provided.
In the pump chamber of the same stage, at least one intake port and one exhaust port are provided on one side with respect to an imaginary plane including the axes of a plurality of shafts on which the respective rotors are mounted, and the other side with respect to this imaginary plane But at least one each. In the same stage of the pump chamber, the intake port and the exhaust port are always adjacent to each other on the same side with respect to the virtual plane. In this way, in the front and rear pump chambers, one or more intake ports and exhaust ports are always present on the same side with respect to the virtual plane, so that the upstream pump chamber is on the same side with respect to the virtual plane. The exhaust port of the chamber and the intake port of the subsequent pump chamber can be sequentially connected. For this reason, there is no need to form a communication path that rotates substantially 180 ° between the pump chamber of the former stage and the pump chamber of the latter stage as in the related art. No need to form. For this reason, since it is sufficient to form a partition simply for the partition between the pump chamber of the former stage and the pump room of the latter stage,
The shaft length of the multi-stage roots pump itself is also reduced. For this reason, the foot space can be reduced, and the ease of installation can be ensured.

Further, when the exhaust port of the upstream pump chamber and the intake port of the downstream pump chamber are sequentially connected on the same side with respect to the virtual plane, it is conceivable to sequentially connect them with an external pipe or the like. Even if this is the case, since the pipes and the like are located on the same side with respect to the virtual plane, the pipes and the like are easy and the manufacturing cost can be reduced. Therefore, in the multi-stage roots pump of the present invention, it is possible to secure the ease of installation due to the miniaturization of the foot space, while realizing a low manufacturing cost.

In the case where three or more rotors form one set, if the even number of rotors forms one set, an odd number of intake ports or exhaust ports are provided on the same side with respect to an imaginary plane in the pump chamber of the same stage. Will be provided. In this case, on the same side with respect to the virtual plane, for an even number of intake ports or exhaust ports, the one of the pump chamber of the front stage and the one of the pump room of the rear stage can be sequentially connected,
An odd number of intake ports or exhaust ports are formed with a communication path that circulates approximately 180 ° between the front pump chamber and the rear pump chamber as in the related art, or connected by an external pipe or the like. Or take steps to do so. On the other hand, if the odd number of rotors forms one set, an even number of intake ports and exhaust ports are necessarily provided on the same side of the virtual plane in the pump chamber of the same stage. In this case, on the same side with respect to the virtual plane, as in the related art, approximately 180 ° is provided between the front pump chamber and the rear pump chamber.
The necessity for forming a circulating communication passage or connecting with an external pipe or the like can be completely eliminated. Therefore, in this case, the effects of the present invention can be more reliably achieved.

[0010] It is preferable to employ a set of three rotors, which is the smallest diameter multi-stage roots pump. Further, when sequentially connecting the exhaust port of the upstream pump chamber and the intake port of the downstream pump chamber on the same side with respect to the virtual plane, it is conceivable to sequentially connect them with an external pipe or the like as described above. It is preferable to connect them by a communication groove recessed in the casing. This is because piping such as an external pipe becomes unnecessary in such a case.

A multi-stage pump device according to the present invention is provided with a multi-stage roots pump according to the present invention, wherein a rotary drive device having a drive main body and a drive shaft protruding from the drive main body and rotationally driven is provided adjacent to the multi-stage roots pump. A drive gear fixed to the drive shaft of the rotary drive device and a driven gear fixed to each shaft of the multi-stage roots pump and transmitted by the drive gear are provided between the pump and the rotary drive device. A timing gear train is provided.

The multi-stage pump device of the present invention integrates the multi-stage roots pump of the present invention with a rotary driving device such as a motor.
In this multi-stage pump device, the driving force transmitted from the drive shaft of the rotary drive device is converted into the rotation of each rotor at each timing gear train including a drive gear and a driven gear and each shaft. For this reason, there is no slippage caused by the belt drive, and the torsion of each shaft is hardly affected in the multi-stage roots pump, so that the driving force of the rotary drive device is converted into the rotation of all rotors in each pump chamber. It is easy to perform the pump action smoothly.

In the multistage pump apparatus according to the present invention, the intake port of the first-stage pump chamber and the exhaust port of the last-stage pump chamber are most separated from each other, and the intake port of the first-stage pump chamber or the last-stage pump chamber is separated. Is opened to the position closest to the timing gear train. In this regard, it is preferable that the exhaust port of the last pump chamber is opened at a position closest to the timing gear train. In such a case, the intake port of the frontmost pump chamber is opened at a position farthest from the timing gear train, and the lubricating oil of the timing gear train is not easily scattered in a room or the like where the intake port is opened. The pressure can be reduced while maintaining the environment in a room or the like.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments and modified embodiments of the present invention will be described below with reference to the drawings. (Embodiment) In the multi-stage pump device according to the embodiment, a multi-stage roots pump P is integrated with a motor M as shown in FIGS. Here, in the multi-stage roots pump P, as shown in FIG. 2, the front housing 1, the first to fifth cylinder blocks 2 to 6, and the rear housing 7 are stacked, and these are not shown with an O-ring interposed therebetween. It is fastened by through bolts and forms a part of the casing.

The front housing 1, the first to fifth cylinder blocks 2 to 6, and the rear housing 7 are formed with three shaft holes parallel to each other and horizontally. Each shaft hole has
Three axes 8 to 10 are accommodated, and a virtual plane FF is imagined including the axes of the first to third axes 8 to 10. In each shaft hole of the front housing 1, bearing devices 1a to 1c that support the first to third shafts 8 to 10 are provided.

In the first to fourth cylinder blocks 2 to 5, for example, the third cylinder block 4, as shown in FIG. 1, a dump chamber-shaped pump chamber 4a having a cross section skewed coaxially is recessed from the rear. A groove for accommodating the O-ring is formed around the pump chamber 4a. In the pump chamber 4a,
A first rotor 11 mounted on the first shaft 8, a second rotor 12 mounted on the second shaft 9, and a third rotor 13 mounted on the third shaft 10 are arranged. First to third rotors 1
Reference numerals 1 to 13 each have a four-leaf shape that rotates while meshing with each other, and three members form one set. Pump room 4a
On the upper wall, the intake port 4b located between the first rotor 11 and the second rotor 12, the second rotor 12 and the third rotor 1
3 and an exhaust port 4c is vertically provided. In the lower wall of the pump chamber 4a, an exhaust port 4d located between the first rotor 11 and the second rotor 12, and an intake port 4e located between the second rotor 12 and the third rotor 13 are provided.
And are vertically penetrated.

First, second, fourth cylinder blocks 2, 3, 5
Similarly, dumpling-shaped pump chambers 2a, 3a, 5a
Are recessed from the rear, and the upper and lower walls of each of the pump chambers 2a, 3a, 5a have similar intake ports 2b, 2e, 3b, 3e, 5b, 5e, as shown in FIGS. Exhaust port 2
c, 2d, 3c, 3d, 5c, and 5d extend vertically. Similar first to third rotors 14 to 22 are arranged in the pump chambers 2a, 3a, and 5a. However, the axial length of the first-stage pump chamber 2a by the first cylinder block 2 is the longest, then the axial length of the pump chamber 3a by the second cylinder block 3 is long, and then the axial length of the pump chamber 4a by the third cylinder block 4. And the axial length of the last pump chamber 5a formed by the fourth cylinder block 5 is the shortest.
Further, the axial lengths of the first to third rotors 11 to 22 also differ according to the axial lengths of these pump chambers 2a, 3a, 4a, 5a.

The fifth cylinder block 6 has a gear-shaped gear chamber 6a recessed from the rear, and a groove for accommodating the O-ring is recessed around the gear chamber 6a. In the gear chamber 6a, a drive gear 23 is fixed to the second shaft 9, and a driven gear 24 is attached to the first shaft 8 and the third shaft 10, respectively.
25 is fixed. The driven gears 24 and 25 mesh with the drive gear 23, respectively, and form a timing gear train together with the drive gear 23.

First through third through holes are provided in each shaft hole of the rear housing 7.
Bearing devices 7a to 7c that support the shafts 8 to 10 are provided. A drive main body 26 of the motor M is fixed to the rear housing 7 by a bolt (not shown), and the second shaft 9 is connected to a drive shaft that protrudes from the drive main body 26 and is driven to rotate by a joint (not shown). As shown in FIGS. 1 and 3, an upper plate 31 is fastened to upper surfaces of the front housing 1, the first to fifth cylinder blocks 2 to 6, and the rear housing 7 via bolts (not shown) via gaskets 30. . On the other hand, as shown in FIGS. 1 and 4, a lower plate 29 is fastened to the lower surfaces of the front housing 1, the first to fifth cylinder blocks 2 to 6 and the rear housing 7 via bolts (not shown) via gaskets 28, as shown in FIGS. ing. These upper and lower plates 31, 29 constitute the rest of the casing.

As shown in FIG. 2, an intake port 1d is vertically provided in the front housing 1, and an exhaust port 7d is vertically provided in the rear housing 7. As shown in FIG. 3, an intake port 31 a communicating with the intake port 1 d of the front housing 1 is vertically provided at a front end of the upper plate 31,
At the rear end of the upper plate 31, an exhaust port 31b communicating with the exhaust port 7c of the rear housing 7 is vertically provided.
And, on the back surface of the upper plate 31, an intake port 31a,
1d and a communication groove 31c communicating the intake port 2b of the first cylinder block 2 with the exhaust port 2c of the first cylinder block 2.
c and a communication groove 31d for communicating the intake port 3b of the second cylinder block 3 with the exhaust port 3c of the second cylinder block 3.
A communication groove 31e that communicates with the intake port 4b of the third cylinder block 4; a communication groove 31f that communicates with the exhaust port 4c of the third cylinder block 4 and the intake port 5b of the fourth cylinder block 5; A communication groove 31g that communicates the exhaust port 5b of the block 5 with the exhaust ports 31b and 7c is recessed. Also, as shown in FIG.
A communication groove 29a for communicating the intake ports 31a and 1d with the intake port 2e of the first cylinder block 2, the exhaust port 2d of the first cylinder block 2 and the intake port 3e of the second cylinder block 3 A communication groove 29b for communication, an exhaust port 3d of the second cylinder block 3, and a third cylinder block 4
A communication groove 29c communicating with the intake port 4e of the third cylinder block 4, a communication groove 29d communicating with the exhaust port 4d of the third cylinder block 4 and the intake port 5e of the fourth cylinder block 5, and an exhaust port 5d of the fourth cylinder block 5 And a communication groove 29e for communicating the air with the exhaust ports 31b and 7c.

As described above, the first set of three pieces constitutes one set.
-3 rotors 14-22, and a multi-stage pump device having a multi-stage roots pump P having the smallest diameter can be obtained. When, for example, it is desired to evacuate a certain room into a decompression chamber using such a multi-stage pump device, in the multi-stage roots pump P, the intake port 31a of the front housing 1 is connected via a hose or the like as shown in FIG. It is opened in the room and the exhaust port 31b of the front housing 1 is connected via a hose or the like.
To the atmosphere or the like. Then, the multi-stage roots pump P is driven by the motor M. Thereby, each of the first to first pump chambers 2a, 3a, 4a, and 5a of the multi-stage roots pump P
Since the three rotors 14 to 22 mesh with each other and rotate,
The pumping action is sequentially performed in each of the pump chambers 2a, 3a, 4a, and 5a, and the air in the room is released to the atmosphere or the like, so that the room can be made a decompression room.

During this time, the multi-stage pump apparatus employs the odd-numbered three rotors 1 to 3 which constitute one set, so that the pump chambers 2a, 3a, 4a,
5a, one intake port 2b and one intake port 2b on the upper side with respect to the virtual plane FF including the first to third axes 8 to 10 respectively.
b, 4b, 5b and exhaust ports 2c, 3c, 4c, 5c, and one intake port 2e, 3e, respectively on the lower side with respect to the virtual plane FF including the axes of the first to third axes 8 to 10. 4
e, 5e and exhaust ports 2d, 3d, 4d, 5d. For this reason, the pump chambers 2a, 3a,
4a and the subsequent pump chambers 3a, 4a, 5a,
One intake port 3b, 4b, 5 above the virtual surface FF
b and the exhaust ports 2c, 3c, 4c always exist, and the virtual surface F
One intake port 2e, 3e, 4e and one exhaust port 2d, 3d, 4d always exist below F. Therefore, the communication grooves 31d and 31d are formed on the back surface of the upper plate 31.
If e and 31f are recessed, above the virtual surface FF,
The exhaust ports 2c, 3c, 4c of the upstream pump chambers 2a, 3a, 4a and the intake ports 3b, 4b, 5b of the downstream pump chambers 3a, 4a, 5a can be easily formed without requiring external pipes or the like. Can be connected sequentially. If the communication grooves 29b, 29c, 29d are recessed on the surface of the lower plate 29, the pump chambers 2a, 3a, 4a at the front stage can be eliminated under the virtual surface FF while eliminating the need for piping such as external pipes. Exhaust port 2
d, 3d, 4d and the suction ports 3e, 4e, 5e of the subsequent pump chambers 3a, 4a, 5a can be easily and sequentially connected. For this reason, it is not necessary to form a relatively long partition wall enclosing a communication path that rotates substantially 180 ° between the upstream pump chamber and the downstream pump chamber as in the related art, as shown in FIG. Since it is sufficient to form a partition just for partitioning between the first-stage pump chambers 2a, 3a, 4a and the second-stage pump chambers 3a, 4a, 5a, the axial length of the multi-stage roots pump P itself is also reduced. For this reason, the foot space can be reduced, and the ease of installation can be ensured.

Therefore, in this multi-stage pump device, it is possible to secure the ease of installation by downsizing the foot space while realizing a low manufacturing cost. Also,
In this multi-stage pump device, the driving force transmitted from the driving shaft of the motor M is a timing gear train including a driving gear 23 and driven gears 24 and 25, and a first to third rotor 8 to 10 and a first to third rotor. The rotation is converted into 14 to 22 rotations. For this reason, there is no slip like driving with a belt,
In the multi-stage roots pump P, each of the first to third shafts 8 to 10
Is hardly affected, the driving force of the motor M is easily converted to the rotation of all the first to third rotors 14 to 22 in the respective pump chambers 2a, 3a, 4a, and 5a, and the pump action is smooth. Easy to be done.

Further, in this multi-stage pump device, the intake port 31a and the exhaust port 31b are most separated from each other, and the exhaust port 31b is opened at a position closest to the timing gear train. For this reason, the intake port 31a is opened at a position farthest from the timing gear train, and the lubricating oil of the timing gear train hardly scatters in a room or the like where the intake port 31a is opened, and the environment in the room or the like is suitable. While maintaining the pressure.

In the embodiment, the first gear ratio in the pump chambers 2a, 3a, 4a, 5a is selected by appropriately selecting the gear ratio between the drive gear 23 and the driven gears 24, 25.
-3 rotors 14-22 can be rotated at an appropriate rotation speed. (Modification) As a modification shown in FIG. 6, for example, the pump chamber 4a is formed in a dumpling shape as if skewered with axes whose cross sections intersect, and three first to third axes 8 to 10 parallel to each other.
The virtual planes FF1 and FF2 can also be imagined by a pair of axes. Even so, above the virtual surfaces FF1, FF2, the exhaust ports 2c, 3c, 4c of the preceding pump chambers 2a, 3a, 4a and the pump chambers 3a, 4a, 5a of the latter stage.
Can easily and sequentially be connected to the intake ports 3b, 4b, 5b.
Further, below the virtual planes FF1, FF2, the exhaust ports 2d, 3d, 4d of the preceding pump chambers 2a, 3a, 4a and the intake ports 3e, 4e, 5e of the subsequent pump chambers 3a, 4a, 5a.
e can be easily and sequentially connected. For this reason, in this case, although it is necessary to provide a communication path slightly longer in the circumferential direction above the virtual surfaces FF1 and FF2,
1. It is sufficient to provide a short communication path in the circumferential direction below FF2.

Therefore, the same operation and effect as in the embodiment can be obtained with this multi-stage pump device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view taken along line II of FIGS.

FIG. 2 is a cross-sectional view in the axial direction of the multi-stage pump device according to the embodiment.

FIG. 3 is a plan view of the multi-stage pump device according to the embodiment;

FIG. 4 is a plan view of a lower plate according to the multi-stage pump device of the embodiment.

FIG. 5 is a schematic diagram showing each pump chamber and the flow of air in the multi-stage pump device according to the embodiment.

FIG. 6 is a partial cross-sectional view similar to FIG. 1, according to a multi-stage pump device of a modified embodiment.

[Explanation of symbols]

P: Multi-stage roots pump 2b, 3b, 4b, 5b, 2e, 3e, 4e, 5e: Inlet 2d, 3d, 4d, 5d, 2c, 3c, 4c, 5c: Exhaust port 2a, 3a, 4a, 5a: Pump Chambers 1, 2 to 6, 7, 29, 31 ... Casing (1 ... front housing, 2 to 6 ... first to 5th cylinder block, 7 ... rear housing, 31 ... upper plate, 29 ... lower plate) 8 to 10 ... first to third axes 11 to 22 ... first to third rotors FF, FF1, FF2 ... virtual surfaces 31d, 31e, 31f, 29b, 29c, 29d ... communication grooves M ... rotation drive device 26 ... drive body 23 ... drive gear 24, 25 ... driven gear

Claims (6)

[Claims] 1. A casing having a plurality of pump chambers each having an intake port and an exhaust port, respectively, and a casing disposed in each of the pump chambers, mounted on a plurality of axes parallel to each other and engaged with each other. A multi-stage roots pump having a rotating rotor, wherein the rotor is a set of three or more rotors, and in the casing, the suction port of the foremost pump chamber is opened, and the The exhaust port is sequentially connected to the intake port of the subsequent pump chamber on the same side with respect to the virtual plane including the axes of the plurality of axes, and the exhaust port of the last pump chamber is opened. Features a multi-stage roots pump. 2. The multi-stage roots pump according to claim 1, wherein an odd number of rotors constitute one set. 3. The multi-stage roots pump according to claim 2, wherein three rotors form one set. 4. The multi-stage according to claim 1, wherein the exhaust port of the first-stage pump chamber and the intake port of the second-stage pump chamber are connected by a communication groove formed in the casing. Roots pump. 5. A multi-stage roots pump according to claim 1, wherein a rotary drive device having a drive main body and a drive shaft protruding from the drive main body and rotationally driven is provided adjacently. A driving gear fixed to the drive shaft of the rotary driving device and a driven gear fixed to each shaft of the multi-stage roots pump and transmitted by the driving gear are provided between the multi-stage roots pump and the rotary driving device. A multi-stage pump device comprising a timing gear train including gears. 6. An inlet port of a frontmost pump chamber is opened at a position farthest from the timing gear train, and an exhaust port of the last pump chamber is opened at a position closest to the timing gear train. The multi-stage pump device according to claim 5, wherein