JP3785404B2 - Roots-type blower oil seal device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oil seal device for a roots-type blower.
[0002]
[Prior art]
As a blower, a Roots-type blower that performs suction and exhaust by rotating a rotor is known (for example, Patent Document 1). The structure of such a roots-type blower will be described with reference to the partial cross-sectional view of FIG. As shown in the figure, the Roots-type blower is formed in the casing 10 and formed in a pumping chamber C1 in which a rotor (not shown) for pumping fluid, for example, air, is housed, and in the gear case 11. And a drive chamber C2 in which the gear 12 and the lubricating oil J are accommodated.
[0003]
Further, the Roots-type blower includes a rotor shaft 13 that extends between the pressure feeding chamber C1 and the driving chamber C2 and transmits the driving force from the gear 12 to the rotor. Further, a side cover 17 is provided between the pressure feeding chamber C1 and the driving chamber C2 in which a chamber C3 in which the bearing 14 and the swing-off ring 15 are housed and a chamber C4 in which the atmosphere opening hole 16 is connected are formed. Yes.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2000-257580
[Problems to be solved by the invention]
However, in the Roots-type blower having the conventional configuration described above, the air R leaked from the pressure feeding chamber C1 when the rotor is rotated and air is pumped enters the driving chamber C2 along the axial direction of the rotor shaft 13. . For this reason, the driving chamber C2 is pressurized. The particles or mist of the lubricating oil J wound up by the gear 12 in the pressurized drive chamber C2 are pushed out to the air opening hole 16 of the side cover 17 on the low pressure side, Leaks out. For this reason, there was a problem that the amount of lubricating oil became insufficient, and the bearings 14 and the gears 12 and the like deteriorated quickly.
[0006]
Therefore, the present invention has been made in view of the above-described situation, and can reliably prevent leakage of the lubricating oil accommodated in the drive chamber, and can prevent deterioration of bearings, gears, and the like due to insufficient oil amount. An object of the present invention is to provide an oil seal device for a roots-type blower.
[0007]
[Means for Solving the Problems]
In order to solve the above problem, the invention according to claim 1 is characterized in that a pressure feeding chamber in which a rotor for pressure feeding fluid is accommodated, a driving chamber in which gears and lubricating oil are accommodated, and between the pressure feeding chamber and the driving chamber. A roots-type blower oil-sealing device that includes a rotor shaft that transmits a driving force transmitted from the gear to the rotor, the rotor shaft being provided between the pressure feeding chamber and the driving chamber. A chamber through which the fluid passes, and an opening communicating with the chamber. The flow of the fluid leaked from the pressure feeding chamber from the pressure feeding chamber toward the driving chamber and along the axial direction of the rotor shaft. Roots Bed, characterized in that forming said groove along a portion on the outer periphery exposed to a chamber of the rotor shaft so as to convert the flow directed radially outward of the rotor shaft It resides in Aburafu apparatus of the word.
[0008]
According to the first aspect of the present invention, the groove provided along the outer periphery of the portion exposed to the chamber of the rotor shaft is directed from the pumping chamber to the drive chamber and along the axial direction of the rotor shaft. The fluid flow is converted into a flow directed radially outward of the rotor shaft. Therefore, the fluid flow along the axial direction of the rotor shaft is converted into a flow radially outward of the rotor shaft by the groove , and discharged from the opening communicating with the chamber. For this reason, the fluid from the pressure feeding chamber does not enter the driving chamber, the pressure increase in the driving chamber can be prevented, and the leakage of the lubricating oil accommodated in the driving chamber can be surely prevented. Moreover, the rotor shaft can be easily assembled as compared with the case where the convex wall portion is provided.
[0013]
According to a second aspect of the invention, a Aburafu apparatus Roots-type blower of claim 1, wherein, Roots-type blowers and providing a convex portion in a position opposite to the groove formation member forming the chamber The oil seal device.
[0014]
According to the second aspect of the present invention , the convex portion is provided at a position facing the groove on the forming member forming the chamber. Therefore, the flow of the fluid from the pumping chamber can be surely made to flow along the groove by the convex portion.
[0015]
According to a third aspect of the present invention, there is provided a roots-type blower oil seal device according to claim 1 or 2 , wherein the groove has an arcuate cross section in the axial direction. Exist.
[0016]
According to invention of Claim 3, the flow of the fluid from the pumping chamber in a groove | channel can be made smooth by making the axial direction cross section of a groove | channel into circular arc shape.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a partial oblique view showing an embodiment of a roots-type blower incorporating the oil seal device of the present invention, and FIG. 2 is a cross-sectional view of the roots-type blower of FIG. As shown in the figure, the Roots-type blower has a pumping chamber C <b> 1 in the casing 10.
[0018]
A pair of rotors 18A and 18B provided on the pair of rotor shafts 13A and 13B are accommodated in the pressure feeding chamber C1. By keeping a very slight gap between the inner wall surface of the pressure feeding chamber C1 and the rotors 18A and 18B, contact between the two is prevented.
[0019]
Further, the suction chamber C1 is provided with a suction port 20A and a discharge port 20B. Further, a pair of gears 12A and 12B are attached to the ends of the rotor shafts 13A and 13B, respectively, and the rotor shafts 13A and 13B are rotated in opposite directions by driving means (not shown). Thereby, the rotors 18A and 18B meshing with each other rotate in opposite directions.
[0020]
As a result, air (= fluid) is sucked into the pumping chamber C1 from the suction port 20A, and the air trapped between the inner wall surface of the pumping chamber C1 and the rotors 18A and 18B is pushed out from the discharge port 20B. It is.
[0021]
The gears 12 </ b> A and 12 </ b> B are housed in a drive chamber C <b> 2 provided in the gear case 11 together with the lubricating oil J. As is clear from the above, the rotor shafts 13A and 13B extend between the pressure feeding chamber C1 and the driving chamber C2. Further, as shown in the partial enlarged cross-sectional view of the Roots-type blower in FIG. 3, the side cover 17 provided between the pressure feeding chambers C1 includes a chamber C3 in which bearings 14A and 14B and swing-off rings 21A and 21B are accommodated. A chamber C4 to which the atmosphere opening hole 16 (= opening) is connected is formed. The rotor shafts 13A and 13B penetrate the chambers C3 and C4.
[0022]
Further, at portions of the rotor shafts 13A and 13B exposed to the chamber C4, at least a part of grooves 21A and 21B having an arcuate section in the axial direction along the outer periphery thereof is formed. By forming the grooves 21A and 21B, it is possible to provide a wall portion W directed in the radial direction of the rotor shafts 13A and 13B. Further, the protrusions 17A and 17B provided on the side cover 17 (= forming member) forming the chamber C4 are inserted into the grooves 21A and 21B so as not to contact the rotor shafts 13A and 13B.
[0023]
According to the configuration as described above, the air R along the axial direction of the rotor shafts 13A and 13B advances along the wall portion W in the grooves 21A and 21B as shown by arrows in the drawing, whereby the rotor It is converted into a flow that goes outward in the radial direction of the shafts 13A and 13B, and is released to the atmosphere from the atmosphere opening hole 16 that communicates with the chamber C4.
[0024]
For this reason, the air R from the pressure feeding chamber C1 does not enter the driving chamber C2, the pressure in the driving chamber C2 is prevented from increasing, and the leakage of the lubricating oil J accommodated in the driving chamber C2 can be reliably prevented. it can. Therefore, it is possible to prevent the bearings 14A and 14B and the gears 12A and 12B from deteriorating due to an insufficient oil amount.
[0025]
As is clear from the above, it can be seen that the grooves 21A and 21B and the wall portion W function as the flow direction changing portion in the claims.
[0026]
Further, as described above, by inserting the convex portions 17A and 17B into the grooves 21A and 21B, the flow of the air R from the pressure feeding chamber C1 can be surely caused to flow along the grooves 21A and 21B. For this reason, it is possible to prevent the air R from the pressure feeding chamber C1 from entering the driving chamber C2 even more reliably. Furthermore, the flow of the air R from the pressure feeding chamber C1 in the grooves 21A and 21B can be made smooth by making the axial cross sections of the grooves 21A and 21B arcs.
[0027]
Further, according to the above-described Roots-type blower, swing shafts 22A and 22B which are simple shapes such as ring shapes and are non-contact type seals are used as the shaft seal parts. As a result, the service life is semi-permanent, there is no need for replacement of parts, and it can be made very cheap and economical compared to contact type seals such as oil seals.
[0028]
In the embodiment described above, the wall portion W is provided by forming the grooves 21A and 21B in the rotor shafts 13A and 13B. However, for example, it is also conceivable to provide a wall portion by forming a convex portion radially outward in the rotor shafts 13A and 13B. Also in this case, the air R can be converted into a flow directed outward in the radial direction by flowing along the wall portion. However, when the convex portion is provided on the rotor shaft, the assembly work becomes complicated, and therefore it is desirable to form the wall portion W by the grooves 21A and 21B as described above.
[0029]
【The invention's effect】
As described above, according to the first aspect of the present invention, the flow along the axial direction of the rotor shaft is converted into the flow toward the radially outer side of the rotor shaft by the groove , from the opening communicating with the chamber. Released. For this reason, the fluid from the pumping chamber does not enter the driving chamber, the pressure increase in the driving chamber can be prevented, and the leakage of the lubricating oil accommodated in the driving chamber can be surely prevented. Progress of deterioration of bearings and gears can be prevented. In addition, since the assembly of the rotor shaft is facilitated as compared with the case where the convex wall portion is provided, it is possible to obtain an oil seal device for a Roots-type blower that achieves cost reduction .
[0032]
According to the second aspect of the present invention, the flow of the fluid from the pressure feeding chamber can surely flow along the groove by the convex portion, so that the fluid from the pressure feeding chamber surely enters the driving chamber. An oil seal device for a Roots-type blower that can prevent an increase in pressure due to the above can be obtained.
[0033]
According to the third aspect of the present invention, since the flow of the fluid from the pressure feeding chamber in the groove can be made smooth by making the axial cross section of the groove into an arc shape, the fluid from the pressure feeding chamber is surely driven. An oil seal device of a roots type blower that can prevent an increase in pressure due to entering the chamber can be obtained.
[Brief description of the drawings]
FIG. 1 is a partial perspective view showing an embodiment of a roots-type blower incorporating an oil seal device of the present invention.
FIG. 2 is a cross-sectional view of the Roots-type blower of FIG.
3 is a partially enlarged sectional view of the Roots-type blower of FIG. 1. FIG.
FIG. 4 is a partial cross-sectional view of a conventional roots-type blower.
[Explanation of symbols]
12A, 12B Gears 13A, 13B Rotor shaft 16 Air release hole (opening)
17 Side cover (forming member)
17A, 17B Convex part 18A, 18B Rotor 21A, 21B Groove (flow direction conversion part)
22A, 22B Swing-off ring C1 Pressure feed chamber C2 Drive chamber C4 Chamber J Lubricating oil W Wall portion (flow direction changing portion)

Claims (3)

A pumping chamber in which a rotor for pumping fluid is accommodated, a driving chamber in which gears and lubricating oil are accommodated, and a driving force transmitted from the gear to the rotor is transmitted to the rotor, extending between the pressure feeding chamber and the driving chamber. A roots-type blower oil seal device comprising a rotor shaft,
A chamber provided between the pumping chamber and the driving chamber, through which the rotor shaft passes, and an opening communicating with the chamber;
The flow of the fluid from the pressure feeding chamber to the drive chamber and leaked from the pressure feeding chamber along the axial direction of the rotor shaft is converted into a flow toward the radially outer side of the rotor shaft. An oil seal device for a Roots-type blower, wherein a groove along the outer periphery is formed in a portion exposed to the chamber . An oil seal device for a roots-type blower according to claim 1 ,
An oil seal device for a Roots-type blower, wherein a convex portion is provided at a position facing the groove on the forming member forming the chamber. An oil seal device for a roots-type blower according to claim 1 or 2 ,
The root-type blower oil seal device, wherein the axial cross section of the groove has an arc shape.

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