JPH1162861A - Rotor for roots blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a phenomenon that partial air on a discharge side counterflows to a suction side and improve volume efficiency by providing a cavity part which communicates within each head part by being opened in the shaft direction and forming the radial dimension of a projected wall extending up to an opening inner end edge of the head part of a rotor and the dimension of the other side end part into specified heights. SOLUTION: A rotor part 1 is formed into a contour shape in which head parts 2 whose peripheral surfaces are arranged at equal angle circle interval of 120 deg. constituted of projecting circular arc curves and a valley part 3 constituted of recessed circular arc curves are continuously connected. The rotor part 1 is provided with a cavity part 4 which is opened in the shaft direction by being communicated within each head part 2. On a boss 6 of one side end part 1a of the rotor part 1, a projected wall 8 extending up to an inner end edge 5a of an opening 5 of the head part 2 is integrally provided. A radial dimension h from the outside diameter surface of the boss 6 of the projected wall 8 is different depending upon the size of the rotor and is provided with at least about 5 mm. In the same way, the radial dimension h of the projected wall 8 corresponding to the dimension of the other side end part 1b is provided within a height range of 0 to 3 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roots blower rotor used for aeration in water treatment facilities, recovery of oil mist, recovery of fume dust generated during electric welding, and the like.

[0002]

2. Description of the Related Art Roots blowers have been manufactured for a long time and are used in various fields. However, since a phenomenon occurs in which some air on the discharge side flows back to the suction side, the volume efficiency is reduced, and the rotary blower is rotated. It is known that mechanical efficiency is lower than blowers and piston type air pumps.

[0003]

In a conventional Roots blower, a portion of the air on the discharge side that leaks to the suction side includes a portion between the maximum diameter portion of the rotor head and the inner peripheral surface of the casing, Between the side ends and the housing surface of the casing, between the rotor heads. Also, in the case of a roots blower using a rotor having a cavity communicating from the discharge side to the suction side between the rotor and the shaft, the above-described backflow phenomenon is remarkable in the cavity near the outer diameter of the shaft. Occurs.

An object of the present invention is to provide a rotor for a roots blower which suppresses a phenomenon that a part of air on a discharge side flows backward to a suction side and improves volumetric efficiency.

[0005]

In order to achieve the above object, according to the first aspect of the present invention, there is provided an ink jet recording head comprising: a head having a circumferential surface formed by a convex arc curve and having a constant valley formed by a concave arc curve; A rotor for a three-leaf or two-leaf roots blower having a rotor portion having a contour shape connected continuously in a thickness and a shaft at a center position of the rotor portion, wherein the rotor is made of a precision cast or sintered alloy material. The rotor portion to be molded is provided with a cavity portion which is open in the axial direction and communicates with each head, and is provided outside a boss for inserting the shaft provided at one side end of the rotor. The projecting wall extending from the radial surface to the inner edge of the opening of the head has a radial dimension of at least
mm, and a dimension corresponding to the above dimension of the other side end is formed to a height of 0 to 3 mm.

In order to achieve the same object, an invention according to claim 2 is characterized in that a head having a circumferential surface formed of a convex arc curve and having an equiangular interval and a valley formed of a concave arc curve are continuous with a constant thickness. A three- or two-lobe roots blower rotor having a rotor portion having a contour shape connected to the rotor portion and a shaft integrally formed at the center position of the rotor portion, wherein the rotor portion has an axial direction. A hollow portion that is open and communicates with each of the heads is provided, and a diameter of a protruding wall extending from an outer diameter surface of the shaft at a portion connected to one side end of the rotor to an inner edge of the opening of the head. It is characterized in that the dimension in the direction is formed at a height of at least about 5 mm, and the dimension corresponding to the above-mentioned dimension at the other side end is formed at a height of 0 to 3 mm.

In order to achieve the same object, the invention according to claim 3 is characterized in that a head having a circumferential surface formed of a convex circular arc at equal angular intervals and a valley formed of a concave circular arc are continuous with a constant thickness. And a rotor for a three-leaf or two-leaf multi-stage roots blower having a rotor portion having a contour shape connected to the rotor portion and a shaft at the center of the rotor portion, which is formed by precision casting or a sintered alloy material. The rotor is provided such that a large number of rotor parts are integrally connected via an intermediate shaft part inserted into a partition part of a casing of the roots blower. A protruding wall provided with a cavity communicating with the inside of the head, extending from an outer diameter surface of a boss for inserting the shaft provided at one side end of the rotor to an inner edge of an opening of the head. The radial dimension of Also formed to a height of about 5 mm, and dimension corresponding to the dimension of the other side end 0~3m
It is characterized by being formed at a height of m.

In order to achieve the same object, the invention according to a fourth aspect is characterized in that a head having a peripheral surface formed of a convex arc curve at an equal angular interval and a valley formed of a concave arc curve are continuous with a constant thickness. A three- or two-leaf multi-stage roots blower rotor having a rotor portion having a contour shape connected to the rotor portion and a shaft integrally formed at a center position of the rotor portion, wherein the rotor is a casing of the roots blower. A plurality of rotor parts are provided so as to be integrally connected via an intermediate shaft part inserted into the partition part of each of the hollow parts, and each rotor part has a hollow part which is open in the axial direction and communicates with each head. A radial dimension of a protruding wall extending from the outer diameter surface of the shaft at a portion connected to one side end of the rotor to the inner edge of the opening of the head is formed at a height of at least about 5 mm. And the other side end Dimension corresponding to the serial dimensions 0~3m
It is characterized by being formed at a height of m.

[0009]

The hollow portion of the rotor is filled with a large amount of air, and the hollow portion functions as an accumulator when the roots blower is operated. Then
The apparent pressure air, which has been heated by the heat of the rotor in the cavity and slightly expanded, produces a pressure-balancing effect with the pressure air that is about to flow back from the discharge side to the suction side. Is prevented from flowing back to the suction side. As a result, loss of air amount due to leakage of air on the discharge side to the suction side is prevented. The temperature in the cavity of the rotor during the operation of the roots blower tends to increase by about 10 to 13 ° C. when the discharge side pressure increases by 0.1 kg / cm ² .

According to this roots blower rotor,
Since the rotor cavity functions as an accumulator, the effect that part of air on the discharge side flows back to the suction side is suppressed, air volume loss is prevented, and volume efficiency can be improved. There is.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of a rotor portion showing a first embodiment, FIG. 2 is a vertical sectional front view of a rotor to which a shaft is fixed, FIG. 3 is a vertical sectional front view of a rotor showing a second embodiment, and FIG. FIG. 5 is a longitudinal sectional front view of a rotor showing a third embodiment, and FIG. 5 is a sectional view of a roots blower using the rotor of the first embodiment.

[0012] In FIGS. 1 and 2, 1 is either formed by precision casting of ductile iron, iron-based, a sintered alloy material of the copper-based with a rotor portion of the integrally molded 3 leaf type Roots blower rotor for R ₁ is there. The rotor portion 1 has a known contour shape in which a head portion 2 whose peripheral surface is arranged at an equal angular interval of 120 degrees formed of a convex arc curve and a valley portion 3 formed of a concave arc curve are continuously connected. , The head 2 and the valley 3
A cavity 4 is formed with a thickness of 10 mm to 10 mm and communicates with the inside of each head 2 and is open in the axial direction. Bosses 6 each having a boss hole 7 for inserting a shaft 10 to be described later are integrally provided at a center position of both side end portions 1a and 1b of the rotor portion 1. One side end 1 of the rotor section 1
The boss 6 a is integrally provided with a protruding wall 8 extending to the inner edge 5 a of the opening 5 of the head 2. Dimension h from the outer diameter surface of the radial boss 6 of the projecting walls 8 may vary depending on the size of the rotor R _1, it is preferably within the height range of 5~20mm According to the experiments conducted by the present inventors, at least about 5mm To be provided. Similarly, a radial dimension h of the protruding wall 8 corresponding to the above dimension of the other side end 1b is provided within a height range of 0 to 3 mm.

The shaft 10 has a bearing insertion portion 10b and a timing gear mounting portion 1 on one side of an intermediate portion 10a.
0c, and the bearing insertion portion 10b and the pulley mounting portion 10d
Is provided. It should be noted that the fact that one of the pair of shafts 10 is not provided with the pulley mounting portion 10d is not different from the known shaft.

As shown in FIG. 2, the shaft 10 is inserted into the boss holes 7, 7 of the rotor portion 1 and is supported by the bosses 6, 6. Then, the shaft 10 and the bosses 6, 6 or the valleys 3 are partially welded by facing the welding nozzle (or welding rod) of the electric welding machine from the cavity 4 to securely connect the rotor 1 and the shaft 10. Stick. As described above, a rotor R1 for a three-leaf type roots blower including the shaft 10 at the center position of the rotor unit ₁ is configured.

The rotor R ₂ for a three-lobe roots blower of the second embodiment shown in FIG. 3 is used for a roots blower used for large or special gas applications.
The rotor R ₂ is formed by ductile cast iron or stainless steel precision casting, and the side end portion 101a of the rotor portion 101,
Shafts 110, 110 are integrally formed at the center position of 101b. The other configurations will not be described in detail denoted by the same reference numerals of the one hundred series the same portions is the same as the rotor R _1.

The rotor R of the third embodiment shown in FIG.
Numeral ₃ is used for a three-leaf multistage type, here a two-stage roots blower. The rotor R ₃ is manufactured by precision casting of ductile cast iron or stainless, via the intermediate shaft portion 210a are two rotors portion 201 and 201 to be inserted into the partition wall portion of the roots blower casing (not shown) It is provided so as to be integrally connected. The other configurations will not be described in detail denoted by the same reference numerals in the two hundred series the same portions is the same as the rotor R _1.

The rotor R ₃ has a shaft 210 integrally formed at the center of the rotor portion 201.
According to the rotor R ₁ an exemplary embodiment, it is also possible to manufacture the rotor portion 3 leaf or leaf multistage roots blower rotor for the centered position the shaft 10 of the separate is fixed (not shown) is there.

FIG. 5 shows a roots blower a using the rotor R1 of the _first embodiment. The roots blower a In the casing b provided with a discharge port d and the suction port c, and a pair of rotors R ₁ according to the present invention is mounted, just the top of each head 2 with respect to a conventional method as the casing b inner surface It is configured to have a clearance so as to be assembled almost in contact.

According to the roots blower rotor described above, since the cavity having the projecting wall at the opening portion functions as an accumulator, the phenomenon that a part of air on the discharge side flows backward to the suction side is suppressed, and Volume loss was prevented and volumetric efficiency could be improved.

Next, the results of an experiment for examining the performance of the rotor for a roots blower of the present invention are shown in the graph of FIG. The experiment was performed using a three-leaf roots blower having a diameter of 32 mm, a rotation speed of 2600 rpm, and a motor output of 0.75 kW. As a result of the experiment, it was confirmed that the rotor for the roots blower of the present invention had a small air loss over the entire discharge pressure of 0.1 to 0.3 kg / cm ² and high volumetric efficiency.

[Brief description of the drawings]

FIG. 1 is a perspective view of a rotor section showing a first embodiment.

FIG. 2 is a longitudinal sectional front view of a rotor to which a shaft is fixed.

FIG. 3 is a longitudinal sectional front view of a rotor showing a second embodiment.

FIG. 4 is a longitudinal sectional front view of a rotor showing a third embodiment.

FIG. 5 is a cross-sectional view of a roots blower using the rotor according to the first embodiment.

FIG. 6 is a graph comparing the performance of roots blowers using various rotors.

[Explanation of symbols]

_{R 1, R 2, R 3} → 3 -lobe type Roots blower rotor for h → radial dimension of the protruding wall 1 → rotor portion 1a → one side edge 1b → the other side edge 2 → head 3 → valleys Part 4 → hollow part 5 → opening 5a → inner edge 6 →
Boss 8 → Projecting wall 10 → Shaft

Claims (4)

[Claims] 1. A rotor having a contour shape in which a circumferential surface is formed of a convex arc curve at regular angular intervals and a valley formed of a concave arc curve is connected in a continuous manner at a constant thickness. A three- or two-leaf roots blower rotor having a shaft at the center of the rotor, wherein the rotor portion formed by precision casting or a sintered alloy material has an axial direction opened to allow the inside of each head to be opened. A communicating cavity is provided, and a radially extending projection wall extends from an outer diameter surface of a boss for inserting the shaft provided at one side end of the rotor to an inner edge of the opening of the head. A rotor for a roots blower, wherein the rotor has a height of at least about 5 mm and a dimension corresponding to the above-mentioned dimension of the other side end is formed at a height of 0 to 3 mm. 2. A rotor portion having a contour shape in which a circumferential surface is formed of a convex arc curve and at equal angular intervals, and a valley portion formed of a concave arc curve is continuously connected at a constant thickness with a constant thickness. A three- or two-leaf type roots blower rotor having a shaft integrally formed at the center of the rotor, wherein the rotor portion is provided with a hollow portion that opens in the axial direction and communicates with each head. The radial dimension of the protruding wall extending from the outer diameter surface of the shaft of the portion connected to one side end of the rotor to the inner edge of the opening of the head is formed at a height of at least about 5 mm, and A rotor for a roots blower, wherein a dimension corresponding to the above dimension of the other side end is formed at a height of 0 to 3 mm. 3. A rotor portion having a contour shape in which a circumferential surface is formed of a convex arc curve at regular angular intervals and a valley portion formed of a concave arc curve is connected in a continuous manner with a constant thickness, and said rotor portion. A three- or two-leaf multi-stage roots blower rotor having a shaft at the center of the rotor, wherein the rotor is formed by precision casting or a sintered alloy material and is inserted into a partition wall of a casing of the roots blower. A number of rotor parts are provided so as to be integrally connected via an intermediate shaft part.Each rotor part is provided with a cavity part that opens in the axial direction and communicates with each head part. A radial dimension of a protruding wall extending from an outer diameter surface of a boss for inserting the shaft provided at one side end to an inner edge of the opening of the head is formed at a height of at least about 5 mm. , And on the other side end The size corresponding to the above size is 0 to 3m
A roots blower rotor formed at a height of m. 4. A rotor portion having a contour shape in which a circumferential surface is formed of a convex arcuate curve at equal angular intervals and a valley portion of a concave arcuate curve is connected in a continuous manner at a constant thickness. A three- or two-leaf multi-stage roots blower rotor having a shaft integrally formed at the center position of the roots blower. Are provided so as to be integrally connected to each other, and each rotor is provided with a cavity that opens in the axial direction and communicates with each head,
The radial dimension of the protruding wall extending from the outer diameter surface of the shaft connected to one side end of the rotor to the inner edge of the opening of the head is formed at a height of at least about 5 mm, and The dimension corresponding to the above dimension of the other side end is 0 to 3 m
A roots blower rotor formed at a height of m.