JPH109164A - Screw type fluid machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the suction flow rate of a screw type fluid machine utilizing a lower pressure in the working chamber when it is opened again by providing a suction port having at least one structure for partially interrupting its suction effect during the suction process. SOLUTION: A suction port is structured to be partially closed during its suction process, where it is closed at a rotational angle AM2 of a male rotor and is opened again at a rotational angle AM1 of the rotor. The displacement of the working chamber increases during from AM2 through AM1, while the pressure in the working chamber decreases because of the closed suction port. The forcible drop in pressure of the working chamber increases the suction flow rate through the utilization of a lower pressure therein at or after the rotational angle AM1 of the male rotor which opens the suction port again. The increased suction flow rate in turn improves the volumetric efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a screw fluid machine.

[0002]

2. Description of the Related Art The basic structure of a screw fluid machine is as follows.
The details are described in JP-B-56-17559. Here, the outline of the screw fluid machine will be briefly described with reference to FIG. With the rotation of the male rotor 4 and the female rotor 5,
The working fluid is sucked from the suction port 1 into the working chamber formed by the male rotor 4, the female rotor 5 and the bore 3, and when the working fluid sucked into the working chamber reaches the maximum amount, the suction port 1 is closed. Subsequently, the working chamber volume is reduced to compress the working fluid, and when the desired volume ratio is reached, the compressed working fluid is discharged from the discharge port 2. FIG.
FIG. 6 shows the shape of the suction port 1 shown in the II section. 6 and 7 are the rotation center of the male rotor 4 and the female rotor 5
, The rotation center of 8 and 9 are the male rotor side bore wall surface and the female rotor side bore wall surface, 10 is the suction start line, 11 and 12
Denotes a male rotor side suction end line and a female rotor side suction end line. The shapes of the male rotor side suction end line 11 and the female rotor side suction end line 12 are respectively the shape of the forward surface 13 of the male rotor 4 and the reverse surface 16 of the female rotor 5 shown in FIG.
It is configured based on the shape of. In general, the edge of the tooth profile advancing in the rotation direction of the male rotor 4 is
3. The lagging edge is referred to as a reversing surface 14, and the edges corresponding to the advancing surface 13 and the reversing surface 14 of the male rotor are referred to as the advancing surface 15 and the reversing surface 16 of the female rotor, respectively.

FIG. 8 shows a change in volume and pressure in the working chamber formed by one groove of the male rotor 4 and a corresponding groove of the female rotor 5 and the bore 3. Male rotor 4
The suction of the working fluid is started at the rotation angle a, and the suction port 1 is closed at the angle b. During this time, the suction pressure is almost constant. When the suction is completed, the process proceeds to the compression step, in which the working fluid is compressed to the rotation angle c that is the desired volume ratio, and then the discharge is started.

[0004]

Although the suction pressure in the working chamber is almost constant, the screw fluid machine cannot suck the working fluid corresponding to the displacement volume of 100% into the working chamber in the suction state. . One of the causes is that the suction loss due to flow path resistance is large because the screw fluid machine is a high-speed rotation type fluid machine with thousands of revolutions of lubrication type and 10,000 revolutions of non-lubrication type. Also, one of the causes is that the working chamber in the compressed state and the working chamber in the suction state are close to each other due to the structure of the seal line, so that the working chamber moves beyond the seal line to the working chamber in the suction state. Leakage of fluid. Further, since the working chamber in the compressed state and the working chamber in the suction state are in close contact with each other, the working chamber in the suction state may be heated to increase the pressure of the working fluid. As described above, in the conventional screw fluid machine, the suction flow rate into the working chamber is reduced, and the volumetric displacement is reduced because the displacement volume is less than 100%.

An object of the present invention is to partially close the suction port and forcibly reduce the pressure in the working chamber before reaching the end of suction, and to utilize the low pressure in the working chamber when the suction port is opened again. The purpose is to increase the suction flow rate.

[0006]

In order to achieve the above object, the present invention has a bore chamber composed of two bores partially sharing a space, and has a suction port and a discharge port opened to the bore chamber. A casing is provided with a pair of male and female rotors formed in a spiral shape from a plurality of peaks and a plurality of grooves existing between the peaks, and the rotors are rotatably accommodated in the bore while being engaged with each other. , The rotor is directly contacted with the rotor by rotation transmission,
Alternatively, a screw fluid machine that rotates while meshing with the synchronous rotating means and has a plurality of working spaces formed between the rotor and the casing, and has at least one structure that partially interrupts a suction operation during a suction process. A screw fluid machine having a suction port is provided. Further, in the present invention, the end line shape of the structure that partially interrupts the suction operation is configured to be a shape that opens instantaneously when the working space opens again to the suction port. Further, in the present invention, among the end linear shapes of the structure that partially interrupts the suction action, the male rotor side is a retreating surface of the male rotor tooth shape, and the female rotor side is a forward movement of the female rotor tooth shape. It has the same shape as the surface. Also,
In the present invention, the conventional female rotor side suction end line is set at a position returned to the direction opposite to the rotation direction of the female rotor, and the female rotor side suction end line about the rotation center of the female rotor and the female suction end line. The angle formed by the end line of the structure that partially interrupts the suction operation on the rotor side is set to an angle corresponding to at least one groove of the female rotor. In the present invention,
A period in which the suction operation is partially interrupted is set to be longer than a period corresponding to one groove of the rotor.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to FIG. FIG. 1 corresponds to the II plane of FIG. 5 and shows a suction port shape of a screw fluid machine.
In contrast to the conventional suction port shape shown in FIG. 6, FIG. 1 has structures 20 and 23 that partially close the suction ports on the male rotor and female rotor sides as a structure for partially interrupting the suction operation. Here, a structure for partially closing the suction port 1 will be described in detail. First, the end line shape of the structure in which the suction port 1 is partially closed will be described. On the male rotor side, the end line 21 of the structure that partially closes the suction port on the male rotor side and the inner wall 27 on the male rotor side bore
Is PM1, and the intersection with the male rotor tooth bottom side inner diameter line 26 is PM2. Here, the male rotor 4 is rotated at the male rotor rotation center 6, and when the tooth tip of the male rotor 4 coincides with the intersection point PM <b> 1, the end line 21 is configured to have the same shape as the reversing surface 14 of the male rotor 4. Alternatively, the intersection points PM1, PM2
Is defined as an intersection with the reversing surface 14 of the male rotor 4 and the intersection between the intersections PM1 and PM2 is formed as a straight line or an arbitrary shape considering workability. On the female rotor side, the intersection between the end line 24 of the structure that partially closes the suction port on the female rotor side and the female rotor side bore inner wall 29 is PF1, and the intersection between the female rotor tooth bottom side inner diameter line 28 is PF2. Here, the female rotor 5 is rotated about the female rotor rotation center 7, and when the tooth tip of the female rotor 5 coincides with the intersection PF <b> 1, the end line 24 is configured to have the same shape as the advancing surface 15 of the female rotor 5. Alternatively, the intersections PF1 and PF2 are assumed to be the intersections with the advancing surface 15 of the female rotor 5, and the intersections PF1 and PF2 are formed in a straight line or in any shape considering workability. Where the intersection PM
1, PF1 is located at an angle of AM1, AF1 in the rotation direction of the rotor with reference to a straight line connecting the rotation center 6 of the male rotor and the rotation center 7 of the female rotor. Each angle AM
1, AF1

[0008]

## EQU1 ## AM1 = JM + M1, AF1 = JF + LF + F1 (Equation 1) When suction is started again, the opening of the working chambers on the male rotor side and the female rotor side is performed almost simultaneously. JM, JF and LF are the angles indicated in FIG. 7, and JM is the rotation angle corresponding to the reverse surface 14 of the male rotor,
JF is an angle corresponding to the backward movement surface 16 of the female rotor, and LF is an angle corresponding to the forward movement surface 15 of the female rotor. Also, M
1, F1

[0009]

M1: F1 = 1 / number of male teeth: 1 / number of female teeth... (Equation 2)

Next, the starting line shape of the structure for partially closing the suction port will be described. On the male rotor side, the intersection of the start line 22 of the structure that partially closes the male rotor side suction port and the male rotor side bore inner wall 27 is PM3, and the intersection of the male rotor tooth bottom side inner diameter line 26 is PM4. Here, when the male rotor 4 is rotated at the male rotor rotation center 6 and the tooth tip of the male rotor 4 coincides with the intersection PM3, the start line 2
2 has the same shape as the advancing surface 13 of the male rotor 4. Alternatively, as described above, the intersections PM3 and PM4 are regarded as intersections with the forward surface 13 of the male rotor 4, and the intersections PM3 and PM4 are determined.
The space between the PMs 4 is constituted by a straight line or an arbitrary shape in consideration of workability. At this time, the start line 22 is configured so as not to protrude in the male rotor rotation direction from the shape of the advance surface 13 of the male rotor 4 passing between the intersections PM3 and PM4. On the female rotor side, the intersection of the start line 25 of the structure that partially closes the female rotor side suction port and the female rotor side bore inner wall 29 is PF
3. The intersection of the female rotor tooth bottom side inner diameter line 28 is PF4. Here, when the female rotor 5 is rotated around the female rotor rotation center 7 and the tooth tip of the female rotor 5 coincides with the intersection PF3,
The start line 25 is configured to have the same shape as the reverse surface 16 of the female rotor 5. Alternatively, as described above, the intersections PF3 and PF4 are assumed to be the intersections with the reversing surface 16 of the female rotor 5, and the intersection P
A portion between F3 and PF4 is formed in a straight line or an arbitrary shape considering workability. At this time, the start line 25 is located at the intersection PF3.
The female rotor 5 passing between the PFs 4 is configured so as not to protrude in the female rotor rotation direction from the shape of the retreating surface 16. Here, the intersections PM3 and PF3 are located at angles AM2 and AF2 in the rotation direction of the rotor with reference to a straight line connecting the rotation center 6 of the male rotor and the rotation center 7 of the female rotor. Each angle AM2, AF2 is

[0011]

## EQU00003 ## AM2.ltoreq.AM1-KM, AF2.ltoreq.AF1-JF-LF (Equation 3), and the period in which the suction operation is interrupted can be made longer than the period corresponding to one groove of the rotor. JM,
JF and LF are as described above, and KM is
As shown in FIG. 7, the angle corresponds to one groove of the male rotor.

The effect of the above configuration will be described.
Here, one groove of the male rotor 4 and the corresponding female rotor 5
FIG. 2 showing the working chamber volume and pressure change formed by one groove and the bore 3 will be described. AM1 and AM2 indicate the end and the starting male rotor angles of the structure for disabling the suction action in FIG. Conventionally, the suction pressure increases before the end of suction due to leakage from the working chamber in a compressed state, heating of the working chamber, and the like, and suction is obstructed and the flow rate decreases. On the other hand, in the present invention, the suction port has a structure in which the suction port is partially closed during the suction process. The suction port is closed at the male rotor rotation angle AM2, and the suction port is opened again at AM1. Here, the working chamber volume between AM2 and AM1 increases as before, but the working chamber pressure decreases because the suction port is closed. By forcibly reducing the working chamber pressure in this manner, the suction flow rate can be increased using the low pressure in the working chamber after the male rotor rotation angle AM1 at which the suction port is opened again. Further, since the suction flow rate increases, the volume efficiency can be improved.

A second embodiment of the present invention will be described with reference to FIG. The end line shape of the structure that partially closes the suction port is the same as in the first embodiment.
Regarding the starting line shape of the structure in which the suction port is partially closed, the intersections PM3, PM4, PF3 and PF4 are the same as in the first embodiment. PM5, PF respectively
5 is a line segment connecting the intersection points PM3 and PF3 with the male rotor rotation center 6 and the female rotor rotation center 7, and the male rotor tooth bottom side inner diameter line 2
6, the intersection with the female rotor tooth bottom side inner diameter line 28 is shown. Start lines 22, 25 of a structure that interrupts the suction action on each rotor side
May be located at any position on each rotor root inner diameter line from PM5, PF5 to PM4, PF4, and may be formed in an arbitrary shape. Second embodiment of the present invention
According to this embodiment, the starting line shape of the structure that partially closes the suction port is different from that of the first embodiment, which facilitates processing and molding. On the other hand, similarly to the first embodiment, when the suction is started again, the opening of the male rotor side and the female rotor side working chambers can be performed almost simultaneously, and the period during which the suction action is interrupted is reduced by the rotor. It is possible to make the period longer than the period corresponding to one groove. As described above, it is possible to reduce the manufacturing cost and increase the suction flow rate.

A third embodiment of the present invention will be described with reference to FIG. The present embodiment particularly relates to a screw fluid machine having a configuration in which the number of teeth of the male rotor 4 is smaller than the number of teeth of the female rotor 5 by two or more. The shapes of the structures 20, 23 for partially closing the suction port are the same as those in the first and second embodiments. The present embodiment relates to the position of the structure for partially closing the suction port and the position of the female rotor side suction end line. Intersection PF1 between end line 24 of the structure for interrupting the suction operation on the female rotor side and bore inner wall 29 on the female rotor side
The point on the female rotor side bore inner wall 29 from which the angle AF is rotated along the female rotor rotation direction by an angle AF3 is defined as PF7. In addition, the suction end line 1 of the female rotor side of the conventional screw fluid machine
The intersection point PF6 between the second inner wall 29 and the female rotor side bore inner wall 29 is set. When the conventional female rotor side suction end line 12 is rotated around the female rotor rotation center 7 in the opposite direction to the rotation direction of the female rotor and reaches the point PF7 on the female rotor side bore inner wall 29, the present embodiment is performed. Constitutes the suction end line 30 on the female rotor side. In FIG. 4, a portion indicated by a broken line shows a part of a conventional suction port, which is closed in this embodiment. Note that point P
F7 can be located anywhere on the female rotor side bore inner wall 29 within a range not exceeding PF6 in the female rotor rotation direction. Here, the angle AF3 is

[0015]

JF + LF ≦ AF3 ≦ N × (JF + LF) (Equation 4) where N is

[0016]

N = number of teeth of female rotor−number of teeth of male rotor (Equation 5) According to this embodiment, the female rotor can be opened for a period corresponding to one groove of the female rotor at the shortest. Here, the working chamber in the suction process, which is constituted by the corresponding one groove of the male rotor 4 and the female rotor 5 and the bore 3, has a conventional structure. The female rotor side working chamber is in a suction state with the suction port opened to the suction port.
Therefore, in the conventional female rotor side suction end line 12, the period after re-suction is long, and the effect of re-suction is reduced. According to the present embodiment, since the re-suction period on the female rotor side can be set to the shortest period corresponding to one groove of the female rotor, it is possible to reduce the leakage of the working fluid from the working chamber during the re-suction, and to increase It is possible to maintain the suction flow rate.

[0017]

According to the present invention, a suction port having a structure for partially interrupting the suction effect is applied to a screw fluid machine. The suction port is partially closed to forcibly reduce the pressure in the working chamber, and when the suction port is opened again, the suction flow is increased by utilizing the low pressure in the working chamber. Thereby, the suction flow rate can be increased, and the volume efficiency can be improved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a first embodiment.

FIG. 2 is an explanatory diagram of a working chamber volume and a pressure change in the first embodiment.

FIG. 3 is an explanatory diagram of a second embodiment.

FIG. 4 is an explanatory view of a third embodiment.

FIG. 5 is an explanatory view of a screw fluid machine.

FIG. 6 is an explanatory view of a conventional suction port.

FIG. 7 is an explanatory diagram of a rotor tooth profile.

FIG. 8 is an explanatory diagram showing a working chamber volume and a pressure change in a conventional working chamber.

[Explanation of symbols]

6: Male rotor rotation center, 7: Female rotor rotation center, 8: Male rotor side bore wall surface, 9: Female rotor side bore wall surface, 10: Suction start line, 11, 12: Suction end line, 20: Partially closed Structure, 21 ... End line of partially closed structure, 22 ... Start line of partially closed structure, 23 ... End line of partially closed structure, 24 ... End line of partially closed structure, 2
5 ... Start line of partially closed structure, 26 ... Male rotor tooth bottom side inner diameter line, 27 ... Male rotor side bore inner wall, 28 ... Female rotor tooth bottom side inner diameter line, 29 ... Female rotor side bore inner wall.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shinichiro Tazawa 603, Kandamachi, Tsuchiura-shi, Ibaraki Inside the Tsuchiura Plant, Hitachi, Ltd. Inside the mechanical laboratory

Claims (5)

[Claims] 1. A casing having a bore chamber composed of two bores partially sharing a space, having a suction port and a discharge port opened to the bore chamber, a plurality of peaks, and a plurality of peaks and a gap between the peaks. A plurality of male and female rotors formed in a spiral shape from a plurality of grooves, and the rotors are rotatably housed in a state of being engaged with each other in the bore, and the rotors are directly in contact with each other to transmit rotation of contact between the rotors. In a screw fluid machine that rotates while meshing with each other or with a synchronous rotating means and a plurality of working spaces are formed between the rotor and the casing, at least one structure that partially interrupts a suction operation during a suction process is provided. Screw fluid machine with a suction port provided. 2. The screw fluid machine according to claim 1, wherein the end line shape of the structure that partially interrupts the suction action is a shape that opens instantaneously when the working space opens again to the suction port. . 3. The method according to claim 2, wherein the male rotor side is a reversing surface of the male rotor tooth shape, and the female rotor side is a female terminal side. A screw fluid machine that has the same shape as the advance surface of the rotor tooth profile. 4. The female rotor according to claim 2, wherein the conventional suction end line on the female rotor side is set at a position returned to the direction opposite to the rotation direction of the female rotor. A screw fluid machine in which the angle between the suction end line and the end line of the structure that partially interrupts the suction operation on the female rotor side is an angle corresponding to at least one groove of the female rotor. 5. The screw fluid machine according to claim 1, wherein a period during which the suction operation is partially interrupted is longer than a period corresponding to one groove of the rotor.