JPS6347618A - Fluid machine rotor by uneven tooth type spur gear - Google Patents

Abstract

PURPOSE:To facilitate phase alignment by dispensing with a pilot gear and to improve workability, by providing a small tooth form between a large addendum tooth form and a dedendum tooth form and setting a simultaneous intermeshing rate to 1 or more. CONSTITUTION:An addendum 10 having a large tooth form of a curve A-B of rotors 1, 2 is set to a cycloid curve wherein a pitch circle is a rolling circle and a dedendum 11 is set to a trochoid curve of a curve H-J to bring point other than a point H to a non-contact state and an intermediate part is set to a small tooth form 12 and a simultaneous contact rate is set to 1 or more. Since seal points are set to C1-P-C2', C2-P-C1' and b1-P-b2', b2-P-b1', the variation of rotary torque due to fluid pressure difference P1-P2 is made min. to smooth rotation. Since discharge quantity is made large, miniaturization is achieved and, since an intermeshing rate is enlarged, a pilot gear is made unnecessary and a structure can be made simple and assembling can be made easy.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid machine rotor using an unequal toothed spur gear, for example a rotor for a fluid machine such as a blower, a compressor or a flow meter.

[Sub] U support 4 Figure 14 is a diagram showing a typical example of a roots-type rotor commonly used in blowers, compressors, flow meters, etc., and shows a case where the tooth profile curve is a cycloid one-point continuous contact tooth profile. show,
21 and 22 are rotors, 23 and 24 are pilot gears, and 25 is a casing.The following will explain the case of a flow meter as an example.1 As is well known, the pressure difference P between the pressure P on the inflow side and the pressure P2 on the outflow side. , -P is applied to the rotors 1 and 2, which gives rotational torque to the rotors 1 and 2, causing them to rotate in the direction of the arrow via the pilot gears 3 and 4, and with this rotation, the rotation with the casing 25. Since a predetermined amount of fluid is transferred through the space, the flow rate is measured by measuring the number of rotations of this rotor. In the meshing position shown in FIG. 14, the differential pressure receiving area of the rotor 22 is equal to that of the shaft 02, so the rotational torque becomes zero. That is, at a position rotated by 90° in the direction of the arrow from the position shown in Fig. 1, where no rotational torque is generated and the rotation is caused only by the rotational torque of the rotor 21, the rotational torque of the rotor 21 becomes zero, and the rotational torque of the rotor 21 becomes zero. Rotate. Fig. 15 shows the rotational torque of the rotors 21 and 22 as described above, and Fig. 16 shows the inconstant rotation rate, that is, the pulsation rate of the rotor at this time, which is expressed as a function of the rotation angle. It changes like a sine function.

In addition, as in the prior art described above, the meshing ratio is 1.0 with only rotors 21 and 22, which makes it impossible to transmit the rotation of the rotors to each other. The phase is maintained by pilot gears 23, 24 consisting of gears. However, with a two-leaf Roots rotor, it is difficult to accurately match the regular phase, and the workability during assembly, which requires one phase alignment and then mounting the pilot gear, is poor. On the other hand, as shown in FIG. 15, the rotational torque of the rotor 21 and the rotational torque T2 of the rotor 22 vary considerably as they rotate, so it is difficult to transfer torque between the rotors.
-T is large, which causes problems such as an increase in energy loss required for rotation.

for divination The purpose of the present invention is to solve the above-mentioned problems.

As shown in Fig. 1, a large addendum tooth profile 10 (A
-B) and the small tooth profile 12 (B-C-D-E-F~G-H) between the large dedendum tooth profile 11 (H-J)
), the tooth profile contact ratio is 1.0 or more, conduction between the rotors is possible even without a pilot gear, and the rotor has good workability and can be assembled without the need for phasing. be.

Kazuyoshi Ohmadara FIG. 1 is a diagram showing an embodiment of a fluid mechanical rotor according to the present invention, and this figure shows a cross-sectional view along the flow direction. Rotor 1 and rotor 2 have their respective axes 0□, 02
It is assembled with the casing 3 with a small gap therebetween, and is rotated by the torque generated by the differential pressure between the inflow side pressure P and the outflow side pressure P2. Since the rotor of this embodiment is symmetrical about the respective orthogonal axes, it is sufficient to describe the shape of the rotor, or the tooth profile, in terms of quadrants, as shown in FIGS. First, the addendum 10 with a large tooth profile is curved with a curve mA-B, and the dedendum 11 is curved with a curve H-J whose tooth profile is a cycloid curve whose pitch circle is a rolling circle in order to maximize the tooth height ratio. For example, the dedendum tooth profile is set to be a trochoid curve drawn by the intersection point A' of the addendum tooth profile 1o, which is located at a position larger than the outer diameter of the rotor, so that the dedendum tooth profile is non-contact except for the pitch point H.

On the other hand, a curve B-C-D-E to F-G-H is formed in the middle part of the addendum 10 with a large tooth profile and the dedendum 11 with a large tooth profile.
A small tooth profile 12 is provided to provide a simultaneous contact ratio of 1.0 or more and smooth rotational movement can be obtained. At this time, the small tooth profile 12 may be an involute tooth profile or a cycloid tooth profile as is well known, but in this embodiment, it is a cycloid tooth profile in which the rolling circle is half the pitch circle, and the dedendum B-C and E-D are straight lines. The trajectory of the contact point of a pair of rotors configured as 0 or more is Q□~P for a large tooth profile, , Q
/2 and Q2~P −Q 1', and for small tooth profile a, ~P"a', and a, ~P = a 1'
becomes.

In order to further clarify the tooth profile curve of the embodiment described above, the second
The tooth profile curve is shown again in the figure, and its equation is shown below, where R = pitch circle, r0 = effective outer diameter of the small tooth profile, R
0=outer diameter, R,'=intersection of the addendum tooth profile with the X axis, φ=rotation angle, and t=included angle.

(1) Addendum curve of large tooth profile A-Bx=R(2c
os(φ−田) −cos(2φ−ari)y=R(s
in(2φ-aa)-2sin(φ-ari) (2) Dedendum curve of large tooth profile H-JO≦φ≦ta (3) Curve of small tooth profile E-F y” (3cos (upper-φ) -cos (upper -3φ))
(4) Small tooth profile curve G-H x=” (3sin(a=+φ)-sin(a=+
3 φ))y= (3cos(田+φ)−cos
(+3φ)) (5) BC and DE of the small tooth profile are straight lines. In the case of the embodiment shown in FIG.

= Top = 30℃ <, -, R,' = 5R), 6 R,=1.65R r, = 1.2R It is.

Next, in the embodiment shown in FIG. 1, the grooves 4 and 4' formed in the casing 3 and the groove 5 formed in the small tooth profile 12 are relief grooves to avoid the trapping phenomenon of the tooth profile of the fluid. , relief grooves for the large tooth profiles 10 and 11 are formed by drilling curves 4 and 4' along the large dedendum tooth profiles symmetrical to the center line 010□ on one or both end surfaces of the casing 3 with an appropriate area and depth. has been done. In addition, the relief groove 5 of the small tooth profile 12 has two parts that come into contact with each other at the pitch point P.
The dot addendum is cut out in several places on the tooth trace using a metal saw or end mill. Due to this relief groove, the separation point, that is, the sealing point between the inflow pressure P1 and the outflow pressure P2 is set at C1 to p - c 2' in a large tooth profile.
and C2~P-C,', and b1 for small tooth profile.
〜p−b 2′ and b2〜P〜b1′, which are indicated by the dashed lines in the figure, and the fluid pressure difference P□−
Rotor rotational torques T1 and T2 generated by P2
fluctuations can be minimized.

3 to 10 are diagrams showing how the rotor of the above embodiment sequentially rotates according to the flow (FIG. 3) to (FIG. 10), where 0 point is the sealing point, and FIG. □〉T2. Figure 4 shows T = T, (T1≦T2), Figure 5 shows T1<72
．． Figure 6 is T, =T, (T□≧T2), Figure 7 is T-work>
T2. In Fig. 8, T1=T, (Twork≦T2).

FIG. 9 shows the case where T2>T-work, and FIG. 10 shows the case where T2≧T-work.

FIG. 11 is a diagram showing another embodiment of the fluid mechanical rotor according to the present invention, and this embodiment compensates for the defects in tooth profile meshing of the above-mentioned embodiment. That is, in the above-mentioned embodiment, the large dedendum tooth profile H-J becomes a cusp at point H;
Since only the dots are the so-called meshing tooth profile of the cylinder 2, which is involved in meshing, this is not preferable in terms of tooth profile wear (however, there is no problem if a pilot gear is also used.) Therefore, the first
As shown in Fig. 1, a circular arc tooth profile H~ is provided, which is a trochoid curve of a large dedendum tooth profile, and a circular arc tooth profile H~ is joined to a small addendum tooth profile H~G, and a large addendum tooth profile A that meshes with this circular arc tooth profile is provided. ~ B is obtained and all the meshes are configured to be the first mesh.

Effects As mentioned above, the fluid mechanical rotor according to the present invention has a larger discharge amount than the conventional fluid mechanical rotor, and in the case of the embodiment shown in FIG. 1, the discharge amount is 1.46 times that of the conventional technology. Therefore, with the same flow rate, it can be made smaller, and with the same type, the number of revolutions is lower and durability is improved. In addition, since the simultaneous meshing ratio can be increased to 1.0 or more, it becomes possible to transmit power by the rotor itself, which was impossible with the conventional technology of 0.5, and as a result, a pilot gear is no longer necessary. In addition, there is no need for phase matching, which is required when transmitting data using a pilot gear, and the structure is simplified, making assembly easier. Also, by adding relief grooves.

Since the binding phenomenon is eliminated and the effective contact point, that is, the effective sealing point approaches the pitch circle, the rotational torque fluctuation of each rotor due to the pressure difference is reduced, and therefore the torque exchange T, -T2 is reduced, so that the meshing is improved. Since the tooth surface force is minimal, smooth rotational movement can be expected.

FIG. 12 is a diagram showing the rotational torque rate of the embodiment shown in FIG. 1, and it can be seen that the torque fluctuation is significantly reduced and evened out compared to the conventional example shown in FIG. 15. . Fig. 13 is a diagram showing the pulsation rate of the rotor according to the present invention, and although the discharge amount is 1.46 times that of the conventional example, it is still higher than the pulsation rate of the conventional example shown in Fig. 16. It can be seen that the kinetic energy loss is also very small.

[Brief explanation of the drawing]

Fig. 1 is a diagram for explaining one embodiment of the present invention, and is a sectional view along the flow direction, and Fig. 2 is a detailed diagram for explaining the tooth profile curve of the embodiment shown in Fig. 1. , Figures 3 to 1
Figure 0 shows the rotation of the fluid machine rotor according to the flow, Figure 11 is a diagram for explaining another embodiment of the present invention, and Figure 12 shows the rotation of the rotor according to the present invention. FIG. 13 is a diagram showing the pulsation rate of the rotor according to the present invention. FIG. 14 is a diagram showing a conventional cycloid tooth profile Roots rotor. FIG. 15 is a diagram showing a conventional rotor. FIG. 16 is a diagram showing the rotational torque fluctuation rate of . It is a figure showing a pulsation rate. 1.2...Rotor, 3...Casing, 4.4'
, 5... relief groove, 10... addendum with large tooth profile, 11... dedendum with large tooth profile, 12... small tooth profile. Patent Applicant Oval Equipment Industry Co., Ltd. Figure I Figure 2 '1 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 1O Benefits Page 11 Figure 12 Figure 14

Claims (5)

[Claims] (1) In a pair of two-lobed Roots rotors of the same size and shape that are rotatably housed in the casing, a small tooth profile portion is provided between the large addendum tooth profile and the large dedendum tooth profile, resulting in a simultaneous contact ratio. 1. A fluid machine rotor using an unequal tooth spur gear, characterized in that: 1.0 or more. (2) The addendum tooth profile is a cycloid tooth profile in which the pitch circle is a rolling circle, and the sliding ratio of the tooth profile is infinite. A fluid machine rotor using an unequal tooth spur gear according to claim 1, characterized in that the dedendum tooth profile has a trochoidal tooth profile and the trochoid portion of the dedendum tooth profile is non-contact. (3) A part of the dedendum tooth profile in the vicinity of the pitch point is joined by a circular arc tooth profile, and the addendum tooth profile that meshes with the arc tooth profile is configured to form a first mesh. A fluid machine rotor using an uneven toothed spur gear according to item (1) or item (2). (4) A relief groove is bored in the casing part along the large dedendum tooth profile that is symmetrical about the center line, and a part of the tooth trace in the addendum part of the small tooth profile part is cut out diagonally. Claim (1) or (2)
) or (3) A fluid machine rotor using an uneven toothed spur gear. (5) A pilot gear consisting of circular gears of equal size that meshes with each other is disposed on each shaft of the rotor. A fluid machine rotor comprising the uneven toothed spur gear according to any one of the items.