JP2021193292A - Roots blower or roots vacuum pump - Google Patents

Abstract

To provide a roots blower 10 or a roots vacuum pump comprising a shaft sealing mechanism which can prevent lubricating oil 25 from intruding into a rotor chamber 11a from a bearing 16, can prevent liquid and gas of the rotor chamber 11a from leaking to the bearing 16 side, the roots blower or the roots vacuum pump therefore capable of being operated in an energy-saving manner, and enabling the manufacturing cost thereof to be reduced.SOLUTION: A shake-off plate 21 is fastened to a shaft 15a via an O-ring 22, lubricating oil 25 leaking from a bearing 16, and intruding into a ring groove 21d of the shake-off plate 21 is shaken off by a centrifugal force which is generated with the rotation of the shaft 15a, and returned to a storage portion 14a through an oil passage 12d, and the lubricating oil 25 can be thereby prevented from intruding into a rotor chamber 11a of a casing 11. A lip portion slides while contacting with the rotating shaft, and consequently the lubricating oil 25 is prevented from intruding into the rotor chamber 11a even if not using an oil seal which causes an increase of power, thus enabling the energy-saving operation of a roots blower 10.SELECTED DRAWING: Figure 1

Description

The present invention relates to a roots type blower or a roots type vacuum pump, and more particularly to a shaft sealing mechanism of a rotor shaft.

In the roots type blower or the roots type vacuum pump, a pair of rotors that are rotated in opposite directions are incorporated in a rotor chamber provided in a casing. The rotor shaft is rotatably supported by bearings built into the housing assembled in the casing.
A gear cover is attached to the housing to cover the timing gear attached to the shaft. Inside the gear cover, a storage portion for lubricating oil to be supplied to the timing gear and the bearing is provided.
The housing is provided with a shaft sealing mechanism to prevent liquids and gases in the rotor chamber from leaking to the bearing side and to prevent lubricating oil from entering the rotor chamber from the bearings.

Japanese Unexamined Patent Publication No. 6-101674 discloses a roots type blower that employs an oil seal as a shaft sealing mechanism.
Further, Japanese Patent Publication No. 47-2252 discloses a roots type blower that employs a mechanical seal as a shaft sealing mechanism.

Japanese Patent Application Laid-Open No. 6-101674 Jitsukaisho 47-2252 Gazette

Since the oil seal is easy to assemble, the manufacturing cost can be reduced, but the lip portion of the oil seal comes into contact with the shaft, and sliding resistance is generated in the rotating shaft, so that the power is increased. Further, the lip portion may be worn and the lubricating oil of the bearing may enter the rotor chamber, or a condensable gas such as steam or a fluid such as a corrosive gas may leak from the rotor chamber to the bearing side.
Further, when a plurality of oil seals are used to reduce the amount of leakage of lubricating oil and fluid in the rotor chamber, the sliding resistance to the shaft increases, and further heat generation and power increase occur.

On the other hand, the shaft sealing mechanism using the mechanical seal can suppress the leakage of lubricating oil and fluid as compared with the oil seal. However, the manufacturing cost of the mechanical seal is high because the work of assembling to the shaft is extremely troublesome and time-consuming.
Further, when the corrosive gas drained is mixed in the lubricating oil interposed in the sliding contact surface of the mechanical seal, the lubricating oil deteriorates and the durable life of the mechanical seal is shortened.

In view of this problem, the present invention prevents the lubricating oil from entering the rotor chamber from the bearing, prevents the liquid or gas in the rotor chamber from leaking to the bearing side, enables energy-saving operation, and is capable of manufacturing. It is an object of the present invention to provide a roots type blower or a roots type vacuum pump provided with a shaft sealing mechanism capable of reducing the cost.

According to the first aspect of the present invention, the rotor is rotatably assembled in the rotor chamber provided in the casing.
A through hole and a recess are provided, and a housing that penetrates the rotor shaft through the through hole and incorporates a bearing that rotatably supports the shaft in the recess is assembled to the casing.
A gear cover is attached to the housing, which covers the timing gear assembled at the end of the shaft protruding from the housing and has a storage portion for lubricating oil supplied to the timing gear and bearings.
A roots-type blower or roots-type vacuum pump provided with a shaft sealing mechanism in the housing that prevents fluid in the rotor chamber from leaking to the bearing side and prevents lubricating oil from entering the rotor chamber from the bearing.
As the shaft sealing mechanism, an oil passage is formed in the housing so as to communicate the gap portion adjacent to the recess and the gap portion and the storage portion of the gear cover.
The full swing plate on which the ring groove is formed is incorporated into the gap so that the ring groove faces the side surface of the bearing, and is fixed to the shaft via the O-ring.
It is characterized in that the lubricating oil leaking from the bearing and entering the ring groove is shaken off by the centrifugal force accompanying the rotation of the shaft and returned to the reservoir through the oil passage.

The invention according to claim 2 is the roots type blower or roots type vacuum pump according to claim 1.
The bearing is fitted into the recess of the housing via an O-ring, and a rubber seal bearing is used as the bearing.

The invention according to claim 3 is the roots type blower or roots type vacuum pump according to claim 1.
It is characterized by providing a labyrinth mechanism on the shaft between the rotor chamber and the bearing.

The invention according to claim 4 is the roots type blower or roots type vacuum pump according to claim 1.
It features an open window that allows the through hole of the housing to communicate with the atmosphere between the labyrinth mechanism and the gap, and a shaft that penetrates the through hole and a weir with the required clearance on the bearing side of the open window. ..

According to the invention of claim 1, the full swing plate is fixed to the shaft via the O-ring, and the lubricating oil leaking from the bearing and entering the ring groove of the full swing plate is shaken off by the centrifugal force accompanying the rotation of the shaft. Since it is returned to the reservoir through the oil passage, it is possible to prevent the lubricating oil from entering the rotor chamber of the casing.
However, according to the present invention, it is possible to prevent the lubricating oil from entering the rotor chamber without using an oil seal that causes an increase in power because the lip portion slides in contact with the rotating shaft. , Roots blower or roots vacuum pump can be operated with energy saving.

According to the second aspect of the present invention, the intrusion of the lubricating oil into the rotor chamber can be further prevented by the rubber seal of the O-ring and the bearing.

According to the third aspect of the present invention, the pressure inside the gear cover can be prevented from fluctuating due to the pressure inside the casing by the sealing function of the labyrinth mechanism, so that the lubricating oil can be smoothly supplied to the bearing.

According to the fourth aspect of the present invention, the weir can prevent the fluid in the rotor chamber leaking from the labyrinth mechanism from entering the bearing or the gear cover, even if only a small amount.
Further, since the heat inside the casing is dissipated to the atmosphere through the open window, it is possible to prevent the bearing and the lubricating oil from deteriorating due to heat transfer to the bearing and the gear cover.

It is sectional drawing which shows the roots blower which concerns on embodiment of this invention. It is sectional drawing which cut from the 2-2 line of FIG. It is a perspective view which shows the full swing board of the roots blower. It is sectional drawing which shows the full swing plate. It is sectional drawing which cut from the 3-3 line of FIG.

The present invention will be described below with reference to the drawings. FIG. 1 shows a roots type blower 10 according to an embodiment of the present invention. The roots type blower 10 includes a casing 11, housings 12, 13 and a gear cover 14.

The casing 11 is provided with a suction port 11b and a discharge port 11c communicating with the rotor chamber 11a and the rotor chamber 11a, and a pair of rotors 15 (only one rotor is shown) is rotatably incorporated in the rotor chamber 11a.

The housings 12 and 13 are assembled to the left and right open end faces of the casing 11. The housings 12 and 13 are provided with through holes 12a and 13a through which the shaft 15a of the rotor 15 passes, and recesses 12b and 13b for incorporating bearings 16 and 17 that rotatably support the shaft 15a.

Bearings 16 and 17 are fitted in the recesses 12b and 13b, and are prevented from coming off by snap rings 18 and 19. Rubber seal bearings are used for these bearings 16 and 17. Further, as shown in an enlarged view in FIG. 2, the bearing 16 of the housing 12 on the right side is fitted in the recess 12b via the O-ring 20.

The housing 12 on the right side is provided with a gap portion 12c adjacent to the recess 12b, and the full swing plate 21 is incorporated in the gap portion 12c. As shown in FIGS. 3 and 4, the full swing plate 21 has an inner hole 21a formed therein, an inner peripheral surface 21b is erected along the inner hole 21a, and an outer peripheral surface 21c having a diameter larger than that of the inner peripheral surface 21b is formed. It is erected and the ring groove 21d is partitioned by the inner peripheral surface 21b and the outer peripheral surface 21c.
The full swing plate 21 is fixed to the shaft 15a so that the ring groove 21d faces the side surface of the bearing 16 by fitting the inner hole 21a into the O-ring 22 fitted to the shaft 15a. An oil passage 12d is formed in the housing 12 to communicate the gap portion 12c with the storage portion 14a of the gear cover 14, which will be described later.

As shown in FIGS. 1 and 5, a plurality of labyrinth grooves 15b and 15c are formed in parallel on the shaft 15a at a portion close to the rotor chamber 11a as a labyrinth mechanism.
The housing 12 on the right side is formed with an open window 12e that opens a through hole 12a to the atmosphere between the labyrinth groove 15b and the gap portion 12c. Further, a shaft 15a penetrating the through hole 12a and a weir 12f having a required clearance are provided on the bearing 16 side of the open window 12e.
An open window 13c is formed in the housing 13 on the left side in the vicinity of the labyrinth groove 15c.

The timing gear 23 and the oil furikake plate 24 are fixed to the right end of the shaft 15a, and the timing gear 23 and the oil furikake plate 24 are covered with the gear cover 14 assembled to the housing 12. A storage portion 14a for the lubricating oil 25 is provided at the bottom of the gear cover 14. The lubricating oil 25 of the storage portion 14a is scraped up from the storage portion 14a by the oil furikake plate 24 as the shaft 15a rotates, and is supplied to the timing gear 23 and the bearing 16.
Reference numeral 26 is an oil cap, and reference numeral 27 is a belt wheel connected to a drive shaft of a drive motor (not shown) by a belt. The bearing 17 on the left side is lubricated with grease.

The structure of the roots type blower 10 according to this embodiment is as described above.
The full-swing plate 21 is fixed to the shaft 15a via the O-ring 22, and the lubricating oil 25 leaking from the bearing 16 and entering the ring groove 21d of the full-swing plate 21 is shaken off by the centrifugal force accompanying the rotation of the shaft 15a, and the oil passage 12d Since it is returned to the storage portion 14a through the lubricating oil 25, it is possible to prevent the lubricating oil 25 from entering the rotor chamber 11a of the casing 11.
According to this embodiment, it is possible to prevent the lubricating oil 25 from entering the rotor chamber 11a without using an oil seal that increases the power because the lip portion slides in contact with the rotating shaft. , The roots type blower 10 can be operated with energy saving.

The intrusion of the lubricating oil 25 into the rotor chamber 11a can be further prevented by the rubber seals of the O-ring 20 and the bearing 16.

Since the pressure inside the gear cover 14 can be prevented from fluctuating due to the pressure inside the casing 11 by the sealing function of the labyrinth groove 15b, the lubricating oil 25 can be smoothly supplied to the bearing 16.

The weir 12f can prevent the fluid in the rotor chamber 11a that leaks from the labyrinth groove 15b, even if it is small, from entering the bearing 16 and the gear cover 14.
Further, since the heat inside the casing 11 is dissipated to the atmosphere through the open windows 12e and 13c, it is possible to prevent the bearings 16 and 17 and the lubricating oil 25 from deteriorating due to heat transfer to the bearings 16 and 17 and the gear cover 14.

Although the present invention has been applied to the roots type blower 10 in this embodiment, the same operation and effect can be obtained by applying the present invention to the roots type vacuum pump.
Further, although the labyrinth grooves 15b and 15c are formed on the shaft 15a as a labyrinth mechanism, the same action and effect can be obtained by forming the labyrinth grooves on the inner peripheral surfaces of the through holes 12a and 13a.

10 ... Roots type blower 11 ... Casing 11a ... Rotor chamber 11b ... Suction port 11c ... Discharge port 12, 13 ... Housing 12a, 13a ... Through hole 12b, 13b ... Recessed hole 12c ... Void portion 12d ... Oil passage 12e, 13c ... Open window 12f ... Dam 14 ... Gear cover 14a ... Storage section 15 ... Rotor 15a ... Shaft 15b, 15c ... Labyrinth grooves 16, 17 ... Bearings 18, 19 ... Snap ring 20 ... O-ring 21 ... Full swing plate 21a ... Inner hole 21b ... Inner peripheral surface 21c ... Outer peripheral surface 21d ... Ring groove 22 ... O-ring 23 ... Timing gear 24 ... Oil furikake plate 25 ... Lubricating oil

Claims (4)

The rotor can be rotatably assembled in the rotor chamber provided in the casing.
A through hole and a recess are provided, and a housing that penetrates the rotor shaft through the through hole and incorporates a bearing that rotatably supports the shaft in the recess is assembled to the casing.
A gear cover is attached to the housing, which covers the timing gear assembled at the end of the shaft protruding from the housing and has a storage portion for lubricating oil supplied to the timing gear and bearings.
A roots-type blower or roots-type vacuum pump provided with a shaft sealing mechanism in the housing that prevents fluid in the rotor chamber from leaking to the bearing side and prevents lubricating oil from entering the rotor chamber from the bearing.
As the shaft sealing mechanism, an oil passage is formed in the housing so as to communicate the gap portion adjacent to the recess and the gap portion and the storage portion of the gear cover.
The full swing plate on which the ring groove is formed is incorporated into the gap so that the ring groove faces the side surface of the bearing, and is fixed to the shaft via the O-ring.
A roots-type blower or roots-type vacuum pump characterized in that the lubricating oil leaking from the bearing and entering the ring groove is shaken off by the centrifugal force accompanying the rotation of the shaft and returned to the reservoir through the oil passage. The roots type blower or roots type vacuum pump according to claim 1, wherein a bearing is fitted in a recess of the housing via an O-ring and a rubber seal bearing is used as the bearing. The roots type blower or roots type vacuum pump according to claim 1, wherein a labyrinth mechanism is provided on the shaft between the rotor chamber and the bearing. It features an open window that allows the through hole of the housing to communicate with the atmosphere between the labyrinth mechanism and the gap, and a shaft that penetrates the through hole and a dam with the required clearance on the bearing side of the open window. The roots type blower or roots type vacuum pump according to claim 1.

Images