JPH11311191A - Single step root pump, single step pump device, multiple stage root pump and multiple stage pump device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a single stage root pump capable of increasing the compression ratio, and a multiple stage root pump capable of reducing its production cost and ensuring easiness of its installation through the compactness of foot stace. SOLUTION: Rotors 8-10 each of which is composed of a set of three pieces or more are used. In a pump chamber 2a, a suction port 2b made by the first rotor 8 and the second rotor 9 is opened, a discharge port 2d made by the first rotor 8 and the second rotor 9 is connected to a suction port 2e made by the second rotor 9 and the third rotor 10 below a virtual plane FF containing axes of first to third shafts 5-7 on which the rotors 8-10 are mounted, and a discharge port 2c made by the second rotor 9 and the third rotor 10 is opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-stage roots pump driven by a rotary driving device such as a motor and performing a pumping operation in a single-stage pump chamber, and the rotary driving device and the single-stage roots pump integrated. The present invention relates to a single-stage pump device, a multi-stage roots pump driven by the same rotation drive device and sequentially performing a pumping operation in each stage of the pump chamber, and a multi-stage pump device integrating the same rotation drive device and the multi-stage roots pump.

[0002]

2. Description of the Related Art In a commercially available single-stage pump device, a single-stage roots pump is integrated with a motor. Here, in the single-stage roots pump, one pump chamber having an intake port and an exhaust port is formed in a casing. A set of two rotors is disposed in the pump chamber, and 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 pump chamber is opened and an exhaust port is opened. In addition, one of the shafts of the single-stage roots pump is connected to a drive shaft that protrudes from the drive main body of the motor and is driven to rotate. A drive gear is fixed to the tip of one shaft of the single-stage roots pump connected to the drive shaft of the motor, and the drive gear meshes with a driven gear fixed to the tip of the other shaft of the single-stage roots pump. It is designed to transmit the rotation.

When it is desired to evacuate a certain room by using such a motor and a single-stage roots pump to form a decompression chamber, for example, the inlet of the single-stage roots pump is opened into the room, and the exhaust port is opened to the atmosphere. To open. Then, the single-stage roots pump is driven by the motor. As a result, since the rotors mesh with each other and rotate in the pump chamber of the single-stage roots pump, a pumping action is performed in the pump chamber of the single-stage roots pump, releasing air in the room to the atmosphere and depressurizing the room. Room.

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.

[0006]

However, in the above-described conventional single-stage roots pump or single-stage pump device, the single-stage roots pump performs a pumping operation by pumping, and furthermore, a single pump chamber has two rotors. Since a single unit is used, the compression ratio cannot be sufficiently increased. For this reason, even if these are used, the effect of evacuation is hardly seen in reality at present.

[0007] A first object of the present invention is to provide a single-stage roots pump or a single-stage pump device capable of increasing the compression ratio. On the other hand, in the above-mentioned conventional multi-stage roots pump or multi-stage pump device, since the multi-stage roots pump has a plurality of pump chambers, it is possible to increase the compression ratio to some extent, thereby making it possible to exhibit pumping effects such as evacuation. It is possible.

However, in the above-mentioned conventional multi-stage roots pump or multi-stage pump device, as means for sequentially connecting the exhaust port of the front-stage pump room and the intake port of the rear-stage pump room, the former-stage pump room and the latter-stage pump room are connected. A communication path that rotates substantially 180 ° is formed in a partition formed between the two. 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. A second object of the present invention is to provide a multi-stage roots pump or a multi-stage pump device capable of ensuring the ease of installation by reducing the foot space while realizing a low manufacturing cost.

[0010]

(1) A single-stage Roots pump according to the present invention is provided with a casing constituting one pump chamber having an intake port and an exhaust port, and a casing arranged in the pump chamber and parallel to each other. In a single-stage roots pump having rotors mounted on a plurality of shafts and rotating in mesh with each other, the rotors form a set of three or more rotors, and the rotors meshing sequentially are a first rotor, a second roller,. , The (n-1) th rotor and the (n) th rotor, the (n-2) th rotor and the (n-1) th rotor
At least one of the intake port obtained by the rotor and at least one of the intake ports obtained by the (n-1) th rotor and the nth rotor is opened, and the at least one intake port obtained by the (n-2) th rotor and the (n-1) th rotor is opened. The exhaust port is connected to the intake port obtained by the (n-1) -th rotor and the n-th rotor on the same side with respect to an imaginary plane including the axes of the plurality of axes, and The exhaust port obtained by the n-th rotor is opened.

The single-stage Roots pump of the present invention performs a pumping operation by pressure feed as in the prior art, but employs a set of three or more rotors. Here, the sequentially meshing rotors are a first rotor, a second roller,.
To describe the rotor and the n-th rotor, one pump chamber is provided with two or more intake ports and exhaust ports. In the pump chamber, at least one intake port and one exhaust port are provided on one side of a virtual plane including the axes of a plurality of axes, and at least one intake port and one exhaust port are provided on the other side of the virtual plane. is there. In 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. Therefore, the (n-2) th rotor and the (n) th rotor
At least one of the intake port obtained by the (-1) th rotor and the intake port obtained by the (n-1) th rotor and the nth rotor is opened. Further, the exhaust port obtained by the first rotor and the second rotor can be connected to the intake port obtained by the second rotor and the third rotor on the same side with respect to the virtual plane. In succession, the exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor can be connected to the intake port obtained by the (n-1) th rotor and the nth rotor on the same side with respect to the virtual plane. Then, an exhaust port obtained by the (n-1) th rotor and the nth rotor is opened.

Therefore, in the single-stage roots pump of the present invention, since a plurality of pumping actions can be performed in one pump chamber, the compression ratio can be further increased, and pumping effects such as evacuation can be obtained. be able to. In the single-stage roots pump of the present invention, the n-th
When two or more of the intake ports obtained by the second rotor and the (n-1) th rotor and the intake ports obtained by the (n-1) th rotor and the nth rotor are opened, the first intake port is increased. Therefore, a pumping effect such as evacuation can be enhanced.

(2) When three or more rotors constitute one set, if the even number of rotors constitutes one set, the same is applied to an imaginary plane including axes of a plurality of axes in one pump chamber. On the side, one of the intake port and the exhaust port is provided one more than the other. In this case, the pair of intake port and exhaust port can be connected on the same side with respect to the virtual plane, but the first intake port and the last exhaust port are located on opposite sides with respect to the virtual plane. Will be done. If you try to avoid this from the outside, it is almost 180
° Means must be taken to form a circulating communication path or connect with an external pipe or the like. On the other hand, if the odd number of rotors constitutes one set, the same number of intake ports and exhaust ports will be provided on one and the same side of the virtual plane in one pump chamber. In this case, the first intake port and the last exhaust port are located on the same side with respect to the virtual plane. For this reason, it is possible to eliminate the necessity of forming a communication path that rotates around 180 ° or connecting with an external pipe or the like. For this reason, in this case, an excellent appearance can be achieved.

(3) Adopting a set of three rotors is preferable because the multi-stage roots pump has the smallest diameter. (4) In one pump chamber, an exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor, and
When connecting the rotor and the intake port obtained by the n-th rotor on the same side with respect to an imaginary plane including the axes of a plurality of shafts, 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.

(5) In the single-stage pump device of the present invention, the single-stage roots pump of the present invention is provided with a rotary drive device having a drive main body and a drive shaft protruding from the drive main body and driven to rotate. A drive gear fixed to the drive shaft of the rotary drive device, and a drive gear fixed to each shaft of the single-stage roots pump, between the single-stage roots pump and the rotary drive device; And a timing gear train composed of a driven gear that is driven by the transmission.

The single-stage pump device of the present invention has the single-stage roots pump of the present invention integrated with a rotary drive device such as a motor.
In this single-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 shaft including a drive gear and a driven gear and each shaft. For this reason, there is no slippage caused by the belt, and the twist of each shaft is hardly affected in the single-stage roots pump.The driving force of the rotary drive device is converted to the rotation of all rotors in each pump chamber. And the pump action is easily performed smoothly.

(6) A multi-stage roots pump according to the present invention includes a casing having a plurality of pump chambers each having an intake port and an exhaust port, each of which has a plurality of pump chambers arranged in parallel with each other, and a plurality of parallel pump chambers arranged in each of the pump chambers. In a multi-stage roots pump having a rotor mounted on a shaft and rotating in mesh with each other, the rotors form one set of three or more rotors, and the first set of rotors, which mesh sequentially with the same set, a second roller,. ,
The n-th rotor and the n-th rotor, in the foremost pump chamber, the intake port obtained by the n-th rotor and the n-th rotor, the n-th rotor, At least one of the intake ports obtained by the n-th rotor is opened, and the exhaust port obtained by the (n-2) -th rotor and the (n-1) -th rotor is positioned with respect to an imaginary plane including the axes of the plurality of axes. And the n-th pump chamber of the rear stage on the same side
In the pump chamber connected to the intake port obtained by the -1 rotor and the n-th rotor, and in the same stage except for the foremost stage and the last stage, the pump chamber is provided by the (n-2) th rotor and the (n-1) th rotor. The exhaust port is connected to the intake port obtained by the (n-1) -th rotor and the n-th rotor on the same side with respect to the imaginary plane, and is connected to the (n-1) -th rotor in the pump chamber at the last stage. The exhaust port obtained by the n-th rotor is opened.

If three or more multi-stage roots pumps form a set of rotors, the same stage pump chamber can
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 a virtual plane including axes of a plurality of axes, and at least one intake port and one exhaust port are provided on the other side with respect to this virtual plane. It is one by one. 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. For this reason, in the frontmost pump chamber, at least one of the intake ports obtained by the (n-2) th rotor and the (n-1) th rotor and the intake ports obtained by the (n-1) th rotor and the nth rotor is opened. Keep it. In the frontmost pump chamber, the exhaust ports obtained by the (n-1) th rotor and the nth rotor are on the same side with respect to the imaginary plane, and the (n-2) th rotor and the (n-th) It can be connected to the intake port obtained by one rotor. Here, the rear stage means the next and subsequent stages.

In the pump chambers of the same stage except the first and last stages, the exhaust port obtained by the first rotor and the second rotor has the second rotor and the third rotor on the same side with respect to the virtual plane. Can be connected to the intake port obtained. In succession, the exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor can be connected to the intake port obtained by the (n-1) th rotor and the nth rotor on the same side with respect to the virtual plane.

In the pump chamber at the last stage, an exhaust port obtained by the (n-1) th rotor and the nth rotor is opened. 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, it is sufficient to form a partition simply for partitioning between the upstream pump chamber and the downstream pump chamber, so that the axial 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.

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 imaginary plane, an external pipe or the like may be used. 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.

Further, in the multi-stage roots pump of the present invention, two or more of the intake ports obtained by the (n-2) th rotor and the (n-1) th rotor and the intake ports obtained by the (n-1) th rotor and the nth rotor. Is opened, the number of the first intake ports is increased, so that the pumping effect such as evacuation can be enhanced. (7) A multi-stage roots pump according to the present invention includes 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; A multi-stage roots pump having rotors mounted and meshing with each other and rotating with each other, the rotors form one set of three or more rotors, and the rotors meshing sequentially with the same set are first rotor, second roller,. -1 rotor and n-th rotor, in the same stage of the pump chamber that can form a continuous stage except the last stage while including the foremost stage, the n-th rotor and the (n-1) -th rotor At least two of the obtained intake ports and the intake ports obtained by the (n-1) th rotor and the nth rotor are opened,
The exhaust port obtained by the (n-2) -th rotor and the (n-1) -th rotor and the exhaust port obtained by the (n-1) -th rotor and the n-th rotor are virtual surfaces including axes of the plurality of axes. On the same side, the pump chamber of the same stage except for the foremost stage and the last stage is connected to the intake port obtained by the (n-2) th rotor and the (n-1) th rotor of the rear stage of the pump chamber. The exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor is on the same side with respect to the virtual plane.
-1 rotor and the n-th rotor are connected to the intake port, and the exhaust chamber obtained by the (n-1) -th rotor and the n-th rotor is opened in the pump chamber at the last stage. It is characterized by.

In the multi-stage roots pump of the present invention, the intake air obtained by the (n-2) th rotor and the (n-1) th rotor in the same stage pump chamber including the foremost stage but excluding the last stage can form a continuous stage. At least two of the ports and the intake ports obtained by the (n-1) th rotor and the nth rotor are opened. In the same stage of the pump chamber, the exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor and the nth
The exhaust port obtained by the -1 rotor and the n-th rotor is obtained by the (n-2) th rotor and the (n-1) th rotor of the rear pump chamber on the same side with respect to an imaginary plane including the axes of the plurality of shafts. Can be connected to the intake port. Here, the rear stage means the next and subsequent stages.

In the pump chambers of the same stage except the first and last stages, the exhaust ports obtained by the (n-2) th rotor and the (n-1) th rotor have the (n-1) th exhaust port on the same side with respect to the virtual plane. It can be connected to the intake port obtained by the rotor and the n-th rotor. In the pump chamber at the last stage, an exhaust port obtained by the (n-1) th rotor and the nth rotor is opened.

Thus, in this multi-stage roots pump, since the number of inlets at the beginning is increased, a pumping effect such as evacuation can be enhanced. Other functions and effects are the same as those of the multi-stage roots pump of the present invention. (8) When three or more rotors form one set, if the even number of rotors forms one set, on the same side with respect to an imaginary plane including axes of a plurality of shafts in the same stage pump chamber, One of the intake port and the exhaust port is provided one more than the other. In this case, the pair of intake port and exhaust port can be connected on the same side with respect to the virtual plane, but the first intake port and the last exhaust port are located on opposite sides with respect to the virtual plane. Will be done. For this reason, it is necessary to form a communication path that circulates substantially 180 degrees between the pump chamber of the preceding stage and the pump chamber of the subsequent stage, as in the related art, or to take measures to connect them with an external pipe or the like. On the other hand, if the odd number of rotors constitutes one set, the same number of intake ports and exhaust ports are provided on the same side of the virtual plane in the pump chamber of the same stage. In this case, the first intake port and the last exhaust port are located on the same side with respect to the virtual plane. For this reason,
It is possible to eliminate the necessity of forming a communication path that rotates around 180 ° between the pump chamber of the preceding stage and the pump chamber of the subsequent stage as in the related art, or taking measures such as connecting with an external pipe or the like. it can. Therefore, in this case, the effects of the present invention can be more reliably achieved.

(9) Adopting a set of three rotors is preferable because the multi-stage roots pump has the smallest diameter. (10) An exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor in the same stage of the pump chamber;
When sequentially connecting the intake port obtained by the first rotor and the intake port obtained by the n-th rotor on the same side with respect to an imaginary plane including the axes of a plurality of shafts, it is also conceivable to sequentially connect them with an external pipe or the like as described above. However, 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.

(11) In the multistage pump device of the present invention, the multistage roots pump of the present invention is provided with a rotary drive device having a drive body and a drive shaft protruding from the drive body and driven to rotate, adjacent to the multistage roots pump. A drive gear fixed to the drive shaft of the rotary drive device, fixed to each shaft of the multi-stage roots pump, between the multi-stage roots pump and the rotary drive device,
A timing gear train including a driven gear transmitted by the driving gear is provided.

The multi-stage pump device of the present invention integrates the multi-stage roots pump of the present invention with a rotary drive 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.

(12) In the multistage pump device of the present invention, the intake port of the frontmost pump chamber and the exhaust port of the last pump chamber are most separated from each other. Of the pump chamber is opened at 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 foremost pump chamber 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 is opened. The pressure can be reduced while maintaining the environment in a room or the like.

[0030]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 4 and modified embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) In the single-stage pump device of Embodiment 1, FIG.
As shown in FIG. 2 and FIG.
It is integrated with. Here, in the single-stage roots pump P, as shown in FIG. 2, the front housing 1, the first and second cylinder blocks 2, 3 and the rear housing 4 are stacked, and these are illustrated with an O-ring interposed therebetween. A part of the casing is constituted by being fastened by a through bolt which is not provided.

The front housing 1, the first and second cylinder blocks 2, 3 and the rear housing 4 are formed with three shaft holes parallel to each other and horizontally. Each shaft hole has
Three axes 5 to 7 are accommodated, and a virtual plane FF is imagined including the first to third axes 5 to 7. A bearing device 1a that supports the first to third shafts 5 to 7 in each shaft hole of the front housing 1.
To 1c.

As shown in FIG. 1, the first cylinder block 2 has a dump chamber-shaped pump chamber 2 coaxially skewered.
a is recessed from the rear, and a groove for accommodating the O-ring is recessed around the pump chamber 2a. In the pump chamber 2a, a first rotor 8 mounted on the first shaft 5, a second rotor 9 mounted on the second shaft 6, and a third rotor 10 mounted on the third shaft 7 are arranged. Have been. Each of the first to third rotors 8 to 10 has a four-leaf shape that rotates while meshing with each other, and three rotors constitute one set. On the upper wall of the pump chamber 2a, an intake port 2b located between the first rotor 8 and the second rotor 9, a second rotor 9 and a third rotor 10
And an exhaust port 2c located between the two is vertically penetrated. On the lower wall of the pump chamber 2a, an exhaust port 2d located between the first rotor 8 and the second rotor 9, and an intake port 2e located between the second rotor 9 and the third rotor 10 are provided. Are vertically penetrated.

As shown in FIG. 2, the second cylinder block 3 is provided with a gear-shaped gear chamber 3a recessed from the rear.
A groove for accommodating the O-ring is recessed around the gear chamber 3a. In the gear chamber 3a, the drive shaft 1 is attached to the second shaft 6.
1 is fixed, and driven gears 12 and 13 are fixed to the first shaft 5 and the third shaft 7, respectively. Each driven gear 1
Reference numerals 2 and 13 respectively mesh with the drive gear 11, and together with the drive gear 11, constitute a timing gear train.

Each of the shaft holes of the rear housing 4 has
Bearing devices 4a to 4c that support the shafts 5 to 7 are provided. The drive body 14 of the motor M is fixed to the rear housing 4 by bolts (not shown), and the second shaft 6 is connected to the drive body 1.
4, and is connected to a drive shaft that is driven to rotate by a joint (not shown). On the upper surfaces of the front housing 1, the first and second cylinder blocks 2, 3, and the rear housing 4,
As shown in FIGS. 1 and 3, an upper plate 16 is fastened by a bolt (not shown) via a gasket 15. On the other hand, as shown in FIGS. 1 and 4, a lower plate 18 is fastened to the lower surfaces of the front housing 1, the first and second cylinder blocks 2, 3 and the rear housing 4 via a gasket 17 by bolts (not shown). ing. These upper and lower plates 16, 18 form the rest of the casing.

As shown in FIGS. 1 and 3, the upper plate 16 is provided with a vertically extending intake port 16 a communicating with the intake port 2 b of the first cylinder block 2. Exhaust port 1 communicating with exhaust port 2c
6b extends vertically. As shown in FIGS. 1 and 4, a communication groove 18 a for communicating the exhaust port 2 d and the intake port 2 e of the first cylinder block 2 is formed in the surface of the lower plate 18.

As described above, the first set of three pieces forms one set.
A single-stage pump device having a single-stage roots pump P with the smallest diameter can be obtained by employing the rotors 8 to 10. When, for example, it is desired to evacuate a certain room to be a decompression chamber using such a single-stage pump device, in the single-stage roots pump P, as shown in FIG. To the room,
The exhaust port 16b of the upper plate 16 is opened to the atmosphere or the like via a hose or the like. Then, the single-stage roots pump P is driven by the motor M. Thereby, the single-stage roots pump P
Since the first to third rotors 8 to 10 mesh with each other and rotate in the pump chamber 2a, the pumping action is sequentially performed in the pump chamber 2a, and the air in the room is released to the atmosphere or the like to decompress the room. Room.

During this time, the single-stage pump device employs the odd-numbered three rotors 1 to 3 which constitute one set. Therefore, the two suction ports 2 are provided in the pump chamber 2a.
b, 2e and exhaust ports 2d, 2c. These intake ports 2b, 2e and exhaust ports 2d, 2c
In the pump chamber 2a, one each is provided on the upper side with respect to the virtual plane FF including the first to third axes 5 to 7 and one each is provided on the lower side with respect to the virtual plane FF. In the pump chamber 2a, the intake ports 2b, 2e and the exhaust ports 2d, 2c are always adjacent to each other on the same side with respect to the virtual plane FF. Therefore, if the communication groove 18a is recessed in the surface of the lower plate 18, the exhaust port 2d and the intake port 2e of the pump chamber 2a can be connected to the lower side of the virtual surface FF while eliminating the need for piping such as an external pipe. Can be easily connected sequentially.

In this way, in this single-stage pump device, a plurality of pumping actions can be performed in one pump chamber 2a, so that the compression ratio can be further increased and the evacuation can be effectively achieved. . Further, the single-stage pump device has an excellent appearance since the intake port 2b and the exhaust port 2c are provided in the upper plate 16.

In this single-stage pump device, the motor M
The driving force transmitted from the driving shaft is converted into the rotation of the first to third rotors 8 to 10 by the timing gear train including the driving gear 11 and the driven gears 12 and 13 and the first to third shafts 5 to 7. The Rukoto. For this reason, there is no slippage as if driven by a belt.
Since the torsion of the shafts 5 to 7 is hardly affected, the driving force of the motor M is reduced in all the first to third axes in the pump chamber 2a.
The rotation is easily converted to the rotation of the three rotors 8 to 10, and the pump action is easily performed smoothly. (Embodiment 2) In the single-stage pump device of Embodiment 2, FIG.
As shown in FIG. 5, four unillustrated first to fourth rotors forming one set are employed. Other configurations are the same as in the first embodiment.

In this single-stage pump device, the intake ports 2f, 2j are located above the virtual plane FF in the pump chamber 2a.
And two exhaust ports 2i. On the other hand, below the virtual surface FF in the pump chamber 2a, the intake port 2
h is one, and two exhaust ports 2g and 2k are provided. In this case, a pair of intake port 2j, exhaust port 2i, and intake port 2
h and the exhaust port 2g can be connected on the same side with respect to the virtual plane FF, but the first intake port 2
f and the last exhaust port 2k are located on the opposite side of the virtual plane FF. In order to avoid this from the external appearance, it is necessary to form a communication path that rotates substantially 180 degrees or take measures to connect with an external pipe or the like. (Embodiment 3) In the multi-stage pump device of Embodiment 3, FIG.
As shown in FIG. 8 and FIG.
It is integrated with. Here, in the multi-stage roots pump P, as shown in FIG.
The cylinder blocks 22 to 26 and the rear housing 27 are stacked, and these are fastened by through bolts (not shown) with an O-ring interposed therebetween to form a part of the casing.

The front housing 21, the first to fifth cylinder blocks 22 to 26, and the rear housing 27 are formed with three shaft holes parallel to each other and horizontally. The first to third axes 28 to 30 are accommodated in the respective shaft holes, and a virtual surface FF is imagined including the axes of the first to third axes 28 to 30. First to third shafts 28 to 30 are provided in respective shaft holes of the front housing 21.
Are provided.

As shown also in FIG. 7, in the first to fourth cylinder blocks 22 to 25, for example, the third cylinder block 24, a dumpling-like pump chamber 24a similar to that of the first embodiment is provided from the rear. Around the pump chamber 24a.
A groove for receiving the ring is recessed. Pump room 24a
Inside, a first rotor 31 mounted on the first shaft 28, a second rotor 32 mounted on the second shaft 29, and a third rotor 33 mounted on the third shaft 30 are arranged. . Each first
Each of the three rotors 31 to 33 is in the form of a four-lobe that rotates while meshing with each other, and three rotors form one set.
On the upper wall of the pump chamber 24a, an intake port 24b located between the first rotor 31 and the second rotor 32, and a second rotor 3
An exhaust port 24c located between the second and third rotors 33 extends vertically therethrough. In the lower wall of the pump chamber 24a, an exhaust port 24d located between the first rotor 31 and the second rotor 32, and an intake port 24e located between the second rotor 32 and the third rotor 33 are provided. Are vertically penetrated.

First, second, fourth cylinder blocks 22, 2
Similarly, dumpling-shaped pump chambers 22a and 3
23a, 25a are recessed from the rear, and each pump chamber 22
8 and 9 are provided on the upper and lower walls a, 23a and 25a.
, Similar intake ports 22b, 22e, 23b,
23e, 25b, 25e and exhaust ports 22c, 22d, 2
3c, 23d, 25c, and 25d extend vertically. Further, similar first to third rotors 34 to 42 are disposed in the pump chambers 22a, 23a, and 25a. However, the axial length of the first pump chamber 22a of the first cylinder block 22 is the longest, then the axial length of the pump chamber 23a of the second cylinder block 23 is long, and then the axial length of the pump chamber 24a of the third cylinder block 24. And the axial length of the last pump chamber 25a formed by the fourth cylinder block 25 is the shortest. In addition, each of these pump chambers 22
a, 23a, 24a, and 25a according to the axial length.
The shaft lengths of the rotors 31 to 42 are also different.

The fifth cylinder block 26 is provided with a gear-shaped gear chamber 26a recessed from the rear, and a groove for accommodating the O-ring is provided around the gear chamber 26a.
In the gear chamber 26a, a drive gear 43 is fixed to the second shaft 29, and driven gears 44 and 45 are fixed to the first shaft 28 and the third shaft 30, respectively. Each driven gear 44, 4
Numerals 5 respectively mesh with the drive gear 43 and constitute a timing gear train together with the drive gear 43.

The first through first holes are formed in the respective shaft holes of the rear housing 27.
Bearing devices 27a to 27c that support the three shafts 28 to 30 are provided. The drive body 46 of the motor M is fixed to the rear housing 27 by a bolt (not shown), and the second shaft 2
Numeral 9 is connected to a drive shaft that protrudes from the drive main body 46 and is driven to rotate by a joint (not shown). Front housing 2
As shown in FIGS. 7 and 9, an upper plate 48 is fastened to upper surfaces of the first, fifth to fifth cylinder blocks 22 to 26 and the rear housing 27 via bolts (not shown) via gaskets 47. On the other hand, the front housing 2
As shown in FIGS. 7 and 10, on the lower surfaces of the first, fifth to fifth cylinder blocks 22 to 26 and the rear housing 27,
The lower plate 50 is fastened by a bolt (not shown) via the gasket 49. These upper and lower plates 48, 50 constitute the rest of the casing.

As shown in FIG. 9, an intake port 48a communicating with the intake port 22b of the first cylinder block 22 is vertically formed in the upper plate 48, and the upper plate 48 is connected to the exhaust port 25c of the fourth cylinder block 25. Exhaust port 48 communicating
b extends vertically. On the back surface of the upper plate 48, a communication groove 48c communicating the exhaust port 22c of the first cylinder block 22 and the intake port 23b of the second cylinder block 23, and the exhaust port 2c of the second cylinder block 23 are provided.
A communication groove 48d for communicating the third cylinder block 24 with the intake port 24b of the third cylinder block 24; an exhaust port 24c of the third cylinder block 24 and an intake port 25b of the fourth cylinder block 25;
And a communication groove 48e that communicates with the groove is formed. Also,
As shown in FIG. 10, an exhaust port 22d and an intake port 22e of the first cylinder block 22 are provided on the surface of the lower plate 50.
A communication groove 50a for communicating with the second cylinder block 2
A communication groove 5 for communicating the exhaust port 23d with the intake port 23e
0b, a communication groove 50c communicating the exhaust port 24d of the third cylinder block 24 with the intake port 24e, and a communication groove 50d communicating the exhaust port 25d of the fourth cylinder block 25 with the exhaust port 25e. ing.

As described above, the first set of three pieces forms one set.
３3 rotors 31 to 42 can be adopted, and a multistage pump device having a multistage roots pump P having the smallest diameter can be obtained. When, for example, a certain chamber is to be evacuated to a decompression chamber by using such a multi-stage pump device, the suction port 48a of the upper plate 48 is connected to the multi-stage roots pump P via a hose or the like as shown in FIG. An exhaust port 48b of the upper plate 48 is opened through a hose, etc.
To the atmosphere or the like. Then, the multi-stage roots pump P is driven by the motor M. Accordingly, since the first to third rotors 31 to 42 mesh with each other and rotate in the pump chambers 22a, 23a, 24a, and 25a of the multi-stage roots pump P, the pump chambers 22a, 23a, 24a, and 25a sequentially rotate. A pump action is performed, and the air in the room is released to the atmosphere or the like, and the room can be made a decompression room.

In the meantime, in this multi-stage pump apparatus, the first to third rotors 31 to 42, which are an odd number of three, constitute one set, so that the pump chambers 22a, 23a,
4a, 25a, two intake ports 22b, 22e,
23b, 23e, 24b, 24e, 25b, 25e and exhaust ports 22d, 22c, 23d, 23c, 24d, 24
c, 25d, and 25c will be provided. These intake ports 22b, 22e, 23b, 23e, 24b, 24
e, 25b, 25e and exhaust ports 22d, 22c, 23
In the pump chambers 22a, 23a, 24a, and 25a of the same stage, d, 23c, 24d, 24c, 25d, and 25c are respectively 1 at the upper side with respect to the virtual plane FF including the axes of the first to third axes 28 to 30. One each, and one each below the virtual plane FF. In the pump chambers 22a, 23a, 24a, and 25a at the same stage, the virtual surface F
F on the same side with respect to the intake ports 22b, 22e, 23b, 2
3e, 24b, 24e, 25b, 25e and exhaust port 22
d, 22c, 23d, 23c, 24d, 24c, 25
d and 25c are always adjacent. Therefore, if the communication grooves 48c, 48d, and 48e are recessed on the back surface of the upper plate 48, piping such as an external pipe is unnecessary above the virtual surface FF, and the pump chambers 22a, 23a,
4a and the inlets 23b, 24b, 25 of the subsequent pump chambers 23a, 24a, 25a.
b can be easily and sequentially connected. Also, the lower plate 50
When the communication grooves 50a, 50b, 50c, and 50d are recessed on the surface of the pump chamber 22a and 23d on the same stage, piping such as an external pipe is unnecessary below the virtual surface FF.
a, 24a, 25a exhaust ports 22d, 23d, 24d,
25d and the air inlets 22e, 23e, 24e, 25e can be easily and sequentially connected. Therefore, the pump chambers 22a, 23a, 24a at the front stage and the pump chamber 23 at the
It is not necessary to form a relatively long partition wall enclosing a communication path that rotates substantially 180 ° between the pump chambers a, 24a, and 25a. As shown in FIG.
Since it is sufficient to form a partition for simple partitioning between the pump chambers 23a, 24a and the subsequent pump chambers 23a, 24a, 25a, 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, with this multi-stage pump device, it is possible to reduce the manufacturing cost and to ensure the ease of installation by reducing the foot space. Also,
In this multi-stage pump device, the driving force transmitted from the driving shaft of the motor M is the timing gear train including the driving gear 43 and the driven gears 44 and 45, and the first to third shafts 28 to 30.
Thus, the rotation of each of the first to third rotors 31 to 42 is converted. For this reason, there is no slippage caused by driving with a belt.
The motor M
Drive force of each pump chamber 22a, 23a, 24
a, 25a, all the first to third rotors 31 to 42
The rotation of the pump is easily converted, and the pump action is easily performed smoothly.

Further, in this multi-stage pump device, the intake port 48a and the exhaust port 48b are most separated from each other, and the exhaust port 48b is opened at a position closest to the timing gear train. For this reason, the intake port 48a 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 48a is opened. The pressure can be reduced while maintaining the pressure. (Embodiment 4) In the multistage pump device of Embodiment 4, FIG.
As shown in 2 to 15, the front housing 51, the upper plate 52, and the lower plate 53 are different from the third embodiment.

That is, as shown in FIG. 12, the front housing 51 has an intake port 51a vertically penetrating therethrough.
As shown in FIG. 13, an intake port 52 a communicating with an intake port 51 a of the front housing 51 is vertically provided at a front end of the upper plate 52. On the back surface of the upper plate 52, a communication groove 52b for communicating the intake ports 51a, 52a with the intake port 22b of the first cylinder block 22 is provided.
Is recessed. As shown in FIG. 14, a communication groove 53 a for communicating the intake ports 51 a and 52 a with the intake port 22 e of the first cylinder block 22 and an exhaust port 22 d of the first cylinder block 22 are formed on the surface of the lower plate 53. And a communication groove 5 for communicating between an exhaust port 23d of the second cylinder block 23 and an intake port 23e of the second cylinder block 23.
3b is recessed. Other configurations are the same as those of the third embodiment, and thus the same configurations are denoted by the same reference numerals and detailed description thereof will be omitted.

In this multistage pump device, in the frontmost pump chamber 22a, the intake port 22b obtained by the first rotor 34 and the second rotor 35 and the second rotor 35 and the third
The intake port 22e obtained by the rotor 36 is opened into the room. Further, the exhaust port 22d obtained by the first rotor 34 and the second rotor 35 in the foremost pump chamber 22a is located below the imaginary plane FF with the second rotor 38 and the third rotor 38 in the next-stage pump chamber 23a. It is connected to the intake port 23e obtained by the rotor 39.
Furthermore, the second rotor 3 in the frontmost pump chamber 22a
The exhaust port 22c obtained by the fifth and third rotors 36 is
The next-stage pump chamber 23a above the virtual surface FF
Is connected to the intake port 23b obtained by the first rotor 37 and the third rotor 38 in the first embodiment. Thus, in this multi-stage pump device, the intake ports 22b, 22
Since e is larger than that of the third embodiment, the effect of evacuation can be enhanced. Other operations and effects are described in Embodiment 3.
It is similar to that of

In the first to fourth embodiments, the driving gear 1
By appropriately selecting the gear ratio and the like between the pump chambers 1 and 43 and the driven gears 12, 13, 44 and 45, the pump chambers 2a and 3
a, 4a, 5a, 22a, 23a, 24a, 25a, the first to third rotors 8 to 10, 31 to 42 can be rotated at an appropriate rotation speed. (Modification) As shown in FIG. 16, as a modification of the single-stage or multi-stage pump device, for example, a pump chamber 2a is formed in a dumpling shape skewered by an axis whose cross section intersects. The virtual planes FF1 and FF2 can also be imagined by a pair of axes of the first to third axes 5 to 7. Even in this case, the exhaust port and the intake port can be easily connected sequentially above the virtual surfaces FF1 and FF2. Also, the virtual surface F
The exhaust port and the intake port can be easily and sequentially connected under F1 and FF2. Therefore, in this case, the virtual surface F
Although it is necessary to provide a slightly longer communication path in the circumferential direction above F1 and FF2, it is sufficient to provide a shorter communication path in the circumferential direction below the virtual surfaces FF1 and FF2.

Therefore, the single-stage or multi-stage pump device can provide the same functions and effects as those of the first to fourth embodiments.

[Brief description of the drawings]

FIG. 1 relates to a single-stage pump device according to a first embodiment;
2 is a sectional view taken along the line II of FIG.

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

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

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

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

FIG. 6 is a schematic diagram showing a pump chamber and a flow of air in a single-stage pump device according to a second embodiment.

FIG. 7 relates to a multi-stage pump device according to a third embodiment;
FIG. 7 is a sectional view taken along line VII-VII of FIG.

FIG. 8 is a sectional view in the axial direction of the multistage pump device according to the third embodiment.

FIG. 9 is a plan view of the multi-stage pump device according to the third embodiment.

FIG. 10 is a plan view of a lower plate according to the multi-stage pump device of the third embodiment.

FIG. 11 is a schematic diagram showing each pump chamber and the flow of air in the multi-stage pump device according to the third embodiment.

FIG. 12 is a sectional view in the axial direction of the multi-stage pump device according to the fourth embodiment.

FIG. 13 is a plan view of the multi-stage pump device according to the fourth embodiment.

FIG. 14 is a plan view of a lower plate according to the multi-stage pump device of the fourth embodiment.

FIG. 15 is a schematic diagram showing each pump chamber and the flow of air in the multi-stage pump device according to the fourth embodiment.

FIG. 16 relates to a modified single-stage or multi-stage pump device;
FIG. 8 is a partial sectional view similar to FIG. 1 or FIG. 7.

[Explanation of symbols]

P: single-stage roots pump, multi-stage roots pump 2b, 2e, 2f, 2h, 2j, 22b, 22e, 23
b, 23e, 24b, 24e 25b, 25e ... intake ports 2d, 2c, 2g, 2i, 2k, 22d, 22c, 23
d, 23c, 24d, 24c, 25d, 25c ... exhaust ports 2a, 22a, 23a, 24a, 25a ... pump chambers 1, 21, 51, 2, 3, 22-26, 4, 27, 1
6, 48, 52, 18, 50, 53 ... casing (1,
21, 51 ... front housing, 2, 3 ... first and second cylinder blocks, 22 to 26 ... first to 5 cylinder blocks,
4, 27 ... rear housing, 16, 48, 52 ... upper plate, 18, 50, 53 ... lower plate) 5-7, 28-30 ... 1st to 3rd shafts 8 to 10, 31 to 42 ... 1st to 3rd Rotor FF, FF1, FF2 ... virtual surface 18a, 16d, 48c, 48d, 48e, 50a, 5
0b, 50c, 50d52b, 53a, 53b: communication groove M: rotary drive device 14, 46: drive body 11, 43: drive gear 12, 13, 44, 45: driven gear

Claims (12)

[Claims] 1. A casing constituting one pump chamber having an intake port and an exhaust port, and a rotor arranged in the pump chamber, mounted on a plurality of mutually parallel shafts, and rotated by meshing with each other. A single-stage roots pump having three or more rotors forming a set, and sequentially engaging the rotors with a first rotor, a second roller,.
As the n-th rotor, the n-th rotor and the n-th rotor
At least one of the intake port obtained by one rotor and the intake port obtained by the (n-1) th rotor and the nth rotor is opened, and the at least one of the n-2th rotor and the (n-1) th rotor is opened. The obtained exhaust port is connected to the intake port obtained by the (n-1) -th rotor and the n-th rotor on the same side with respect to an imaginary plane including the axes of the plurality of shafts, and A single-stage roots pump, wherein the exhaust port obtained by the pump and the n-th rotor is opened. 2. The single-stage roots pump according to claim 1, wherein an odd number of rotors form a set. 3. The single-stage roots pump according to claim 2, wherein three rotors form one set. 4. An exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor and an intake port obtained by the (n-1) th rotor and the nth rotor are connected by a communication groove recessed in the casing. 4. The method according to claim 1, wherein
The described single-stage roots pump. 5. A single-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 drive gear fixed to the drive shaft of the rotary drive device, and a drive gear fixed to each shaft of the single-stage roots pump, between the single-stage roots pump and the rotary drive device. A single-stage pump device comprising a timing gear train including a driven gear to be transmitted. 6. A casing comprising a plurality of pump chambers each having an intake port and an exhaust port, each casing being arranged in parallel with each other, and being disposed in each of said 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 rotors form one set of three or more rotors, and the first set of rotors, the second set of rollers,.
And the n-th rotor, the n-th rotor, the n-th rotor and the intake port obtained by the (n-2) -th rotor and the (n-1) -th rotor in the foremost pump chamber. At least one of the intake ports obtained by the above is opened, and the exhaust port obtained by the (n-1) -th rotor and the n-th rotor is a rear stage on the same side with respect to an imaginary plane including the axes of the plurality of axes. In the pump chamber of the same stage except for the foremost stage and the last stage, which is connected to the intake port obtained by the (n-2) th rotor and the (n-1) th rotor of the pump chamber,
The exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor is on the same side with respect to the virtual plane.
The exhaust port is connected to the intake port obtained by the rotor and the n-th rotor, and the exhaust port obtained by the (n-1) -th rotor and the n-th rotor is opened in the last stage of the pump chamber. And a multi-stage roots pump. 7. 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 rotors form one set of three or more rotors, and the first set of rotors, the second set of rollers,.
Assuming that the rotor and the n-th rotor are included in the pump chamber of the same stage that can form a continuous stage excluding the last stage while including the foremost stage, it is obtained by the (n-2) th rotor and the (n-1) th rotor. At least two of the intake port and the intake port obtained by the (n-1) th rotor and the nth rotor are opened, and the exhaust port obtained by the (n-2) th rotor and the (n-1) th rotor are provided. The exhaust port obtained by the (n-1) -th rotor and the n-th rotor is located on the same side with respect to an imaginary plane including the axes of the plurality of shafts.
In the pump chamber of the same stage except for the foremost stage and the last stage, which is connected to the intake port obtained by the two rotors and the (n-1) th rotor, the n-2th rotor and the (n-1) th rotor The obtained exhaust port is connected to the intake port obtained by the (n-1) th rotor and the nth rotor on the same side with respect to the imaginary plane, and the n-1th rotor is provided in the pump chamber at the last stage. A multi-stage roots pump, wherein the exhaust port obtained by the pump and the n-th rotor is opened. 8. The multi-stage roots pump according to claim 6, wherein an odd number of rotors form one set. 9. The multi-stage roots pump according to claim 8, wherein three rotors constitute one set. 10. An exhaust port obtained by an (n-2) -th rotor and an (n-1) -th rotor in a same-stage pump chamber,
The multi-stage roots pump according to claim 6, 7, 8 or 9, wherein the intake port obtained by the first rotor and the n-th rotor is connected by a communication groove recessed in the casing. 11. A multi-stage roots pump according to claim 6, 7, 8, 9 or 10, wherein a rotary drive device having a drive body and a drive shaft protruding from the drive body and driven to rotate is provided adjacently. A drive gear fixed to the drive shaft of the rotary drive device, and a drive gear fixed to each shaft of the multi-stage roots pump and transmitted by the drive gear between the multi-stage roots pump and the rotary drive device. A multi-stage pump device is provided with a timing gear train composed of driven gears. 12. The suction port of the frontmost pump chamber is opened at a position farthest from the timing gear train, and the 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 11, wherein: