CN114992122B - Method for reducing meshing gap of screw rotor - Google Patents
Method for reducing meshing gap of screw rotor Download PDFInfo
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- CN114992122B CN114992122B CN202210655826.6A CN202210655826A CN114992122B CN 114992122 B CN114992122 B CN 114992122B CN 202210655826 A CN202210655826 A CN 202210655826A CN 114992122 B CN114992122 B CN 114992122B
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- 238000000034 method Methods 0.000 title claims abstract description 23
- 210000003739 neck Anatomy 0.000 claims abstract description 11
- 238000004519 manufacturing process Methods 0.000 claims abstract description 5
- 230000006872 improvement Effects 0.000 description 5
- 230000008859 change Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000003993 interaction Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000005057 refrigeration Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C18/00—Rotary-piston pumps specially adapted for elastic fluids
- F04C18/08—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing
- F04C18/12—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type
- F04C18/14—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons
- F04C18/16—Rotary-piston pumps specially adapted for elastic fluids of intermeshing-engagement type, i.e. with engagement of co-operating members similar to that of toothed gearing of other than internal-axis type with toothed rotary pistons with helical teeth, e.g. chevron-shaped, screw type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C29/00—Component parts, details or accessories of pumps or pumping installations, not provided for in groups F04C18/00 - F04C28/00
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
- G06F17/10—Complex mathematical operations
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Theoretical Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- General Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- Mathematical Physics (AREA)
- Data Mining & Analysis (AREA)
- Computer Hardware Design (AREA)
- Algebra (AREA)
- Computational Mathematics (AREA)
- Geometry (AREA)
- Mathematical Analysis (AREA)
- Mathematical Optimization (AREA)
- Evolutionary Computation (AREA)
- Pure & Applied Mathematics (AREA)
- Databases & Information Systems (AREA)
- Software Systems (AREA)
- Applications Or Details Of Rotary Compressors (AREA)
Abstract
The invention discloses a method for reducing meshing clearance of a screw rotor. The rotors include intermeshing male and female rotors, each rotor having journals at its ends for sliding engagement with bearing shells mounted on the equipment housing. The method comprises the following steps: step 1, setting the center distance between two groups of bearing bushes as A; step 2, calculating the variation delta A according to the moving amplitude of the rotor journal relative to the corresponding bearing bush when the rotor is meshed; step 3, designing and manufacturing a male rotor and a female rotor by taking A+DeltaA as a rotor center distance; and 4, mounting the bearing bushes by taking the center distance as A, and mounting the male and female rotors on the shell so that the shaft necks of the rotors are in sliding fit with the corresponding bearing bushes. The invention not only maintains the advantages of strong bearing capacity, small size, low cost and long service life of the sliding bearing, but also solves the problem of low efficiency caused by gaps.
Description
Technical Field
The invention relates to a method for reducing a mechanical meshing gap, in particular to a method for reducing a meshing gap of a screw rotor based on sliding bearing installation.
Background
Screw compressors have been widely used in the fields of general air compression, industrial and commercial refrigeration, etc. because of their unique advantages.
The rotor of the traditional screw compressor is supported by a rolling bearing, and has the defects of complex structure, small bearing area, weak bearing capacity and the like. Radial sliding bearings have been increasingly used in screw compressors because of their simple structure, large bearing area, ability to withstand large impact loads, relatively small size, low cost, long life, etc.
However, the sliding bearing structure has a certain clearance (clearance between the rotor journal and the bearing shell), which causes the rotor meshing clearance to become large, thereby reducing the efficiency of the compressor. In order to solve the efficiency problem of the compressor, the prior art has proposed many means such as increasing the flow area between rotor teeth, reducing the contact line length, reducing the leakage delta area, etc. However, these methods cannot reduce the engagement gap, and cannot fundamentally solve the problem of efficiency degradation caused by the gap.
Similarly, other mechanical devices based on screw mechanical rotors, such as screw expanders and screw pumps, have the problems described above.
Disclosure of Invention
The invention provides a method for reducing meshing clearance of a screw rotor, which aims to: the meshing clearance brought by the sliding bearing is reduced.
The technical scheme of the invention is as follows:
a method of reducing the backlash of a screw rotor, the rotor comprising intermeshing male and female rotors, each rotor having journals at its ends for sliding engagement with bearing shells mounted on a housing of the apparatus, the method comprising the steps of:
step 1, setting the center distance between two groups of bearing bushes as A;
step 2, calculating the variation delta A according to the moving amplitude of the rotor journal relative to the corresponding bearing bush when the rotor is meshed;
step 3, designing and manufacturing a male rotor and a female rotor by taking A+DeltaA as a rotor center distance;
and 4, mounting the bearing bushes by taking the center distance as A, and mounting the male and female rotors on the shell so that the shaft necks of the rotors are in sliding fit with the corresponding bearing bushes.
As a further improvement of the method for reducing the meshing clearance of the screw rotor: in step 2, the unilateral gap between the shaft neck of the male rotor and the bearing bush is set as beta 1 The unilateral gap between the female rotor shaft neck and the bearing bush is beta 2 The stress angle of the male rotor is alpha when engaged 1 The stress angle of the female rotor is alpha when engaged 2 The minimum working oil film thickness of the bearing bush of the male rotor is h 1 The minimum working oil film thickness of the female rotor bearing bush is h 2 Then:
。
as a further improvement of the method for reducing the meshing clearance of the screw rotor: in step 3, when designing the male and female rotors, the meshing gap of the rotors gradually increases from the pitch circle to the tooth tip.
As a further improvement of the method for reducing the meshing clearance of the screw rotor: the meshing gap at the pitch circle was 0.0004 (a+. DELTA.A), and the meshing gap at the tooth tip was 0.0008 (a+. DELTA.A).
As a further improvement of the method for reducing the meshing clearance of the screw rotor: the molded line of the rotor is a unilateral molded line, namely a female rotor molded line is arranged in a female rotor pitch circle, and a male rotor molded line is arranged outside a male rotor pitch circle;
or double-sided molded lines, namely molded lines of the female rotor are distributed on two sides of a pitch circle of the female rotor, and molded lines of the male rotor are distributed on two sides of the pitch circle of the male rotor.
As a further improvement of the method for reducing the meshing clearance of the screw rotor: let the number of teeth of the male rotor be Z1 and the number of teeth of the female rotor be Z2, then the values of Z1 and Z2 need to satisfy the following conditions at the same time:
(1) Z2—z1=0 or 1 or 2 or 3;
(2) Z1 is a positive integer between 2 and 8.
Compared with the prior art, the invention has the following beneficial effects: (1) The rotor design and manufacturing center distance is larger than the center distance of the bearing bush, so that the gap caused by deflection when the rotor is meshed under the sliding bearing structure is reduced, the advantages of strong bearing capacity, small size, low cost and long service life of the sliding bearing are reserved, and the problem of low efficiency caused by the gap is solved; (2) The center distance variation delta A is calculated according to the clearance of the sliding bearing, the oil film thickness and the stress angle of the rotor, when the rotors are deviated due to meshing, the actual center distance between the rotors is exactly equal to the center distance A+delta A during design and manufacturing, so that the rotors are ensured to operate in a meshing mode in an ideal state; (3) The rotor adopts gradual change type meshing clearance, and the clearance increases gradually from pitch circle to tooth top, guarantees that the rotor meshes in pitch circle department, and the rotor operation is more steady, has reduced the noise and the vibration that the rotor produced because of meshing under eccentric state.
Drawings
FIG. 1 is a schematic diagram of conventional male and female rotor engagement, wherein A is the center distance of the male and female rotors and the center distance of a bearing bush;
FIG. 2 is a schematic illustration of the clearance between the journal and the corresponding bearing shell when the male and female rotors have not yet deflected the journal due to meshing;
fig. 3 is a schematic diagram of the relative positions of the journal and the corresponding bearing shell when the male and female rotors are engaged.
Detailed Description
The technical scheme of the invention is described in detail below with reference to the accompanying drawings:
the embodiment provides a method for reducing the meshing clearance of a screw rotor, which is suitable for a screw compressor, a screw expander, a screw pump and the like.
The rotors include intermeshing male and female rotors, each rotor having journals at its ends for sliding engagement with bearing shells mounted on the equipment housing.
As shown in fig. 1 and 2, the conventional design is: the center distance of the bearing bush and the center distance of the rotor are both A. In an ideal state, a gap with equal thickness exists between the shaft neck and the bearing bush of the rotor.
However, as shown in fig. 3, during actual engagement, the journals of the rotors inevitably shift relative to the bearing bushes due to the interaction force between the rotors, and the distance between the rotors increases, so that the engagement gap between the rotors increases, and the working efficiency of the rotors is affected.
The present embodiment solves the problem of gap enlargement by the following method:
and step 1, still setting the center distance between the two groups of bearing bushes as A.
And 2, calculating the variation delta A according to the moving amplitude of the rotor journal relative to the corresponding bearing bush when the rotor is meshed.
Specifically, as shown in fig. 2 and 3, the unilateral gap between the shaft neck of the male rotor and the bearing bush is beta 1 The unilateral gap between the female rotor shaft neck and the bearing bush is beta 2 The stress angle of the male rotor is alpha when engaged 1 The stress angle of the female rotor is alpha when engaged 2 The minimum working oil film thickness of the bearing bush of the male rotor is h 1 The minimum working oil film thickness of the female rotor bearing bush is h 2 Then:
。
and 3, designing and manufacturing a male rotor and a female rotor by taking the A+DeltaA as the center distance of the rotor.
When the rotor is designed, the molded line of the rotor can be a unilateral molded line, namely a female rotor molded line is arranged in a female rotor pitch circle, and a male rotor molded line is arranged outside a male rotor pitch circle; the profile of the female rotor is distributed on two sides of the pitch circle of the female rotor, and the profile of the male rotor is distributed on two sides of the pitch circle of the male rotor.
As a preferred mode of tooth number calculation: let the number of teeth of the male rotor be Z1 and the number of teeth of the female rotor be Z2, then the values of Z1 and Z2 need to satisfy the following conditions at the same time:
(1) Z2—z1=0 or 1 or 2 or 3;
(2) Z1 is a positive integer between 2 and 8.
And 4, mounting the bearing bushes by taking the center distance as A, and mounting the male and female rotors on the shell so that the shaft necks of the rotors are in sliding fit with the corresponding bearing bushes.
As shown in fig. 3, after modification, the rotor still shifts relative to the bearing shell when engaged. According to the geometric relation in the meshing state, the center distance of the rotor after the offset is exactly equal to the actual design center distance A+DeltaA, that is, the meshing clearance of the rotor in the offset state is the meshing clearance in the design, and the rotor runs in the design clearance, so that the ideal working efficiency can be ensured.
On the other hand, because the rotor is always meshed in an offset state, the gap between the journal and the bearing bush is the minimum oil film thickness, and when the load and the rotating speed change, the offset position can change slightly, so that noise and vibration are more likely to occur. To solve this problem, when designing a male and female rotor, the meshing gap of the rotor is changed to a gradual change: gradually increasing from the pitch circle to the tooth tip. Preferably, the pitch circle has a mesh gap of 0.0004 (a+Δa), and the tooth tip has a mesh gap of 0.0008 (a+Δa). The mode can ensure that the rotors are meshed at the pitch circle, the rotor operates more stably, and noise and vibration are reduced.
Claims (5)
1. A method of reducing the backlash of a screw rotor, the rotor comprising intermeshing male and female rotors, each rotor having journals at its ends for sliding engagement with bearing shells mounted on a housing of the apparatus, the method comprising the steps of:
step 1, setting the center distance between two groups of bearing bushes as A;
step 2, calculating the variation delta A according to the moving amplitude of the rotor journal relative to the corresponding bearing bush when the rotor is meshed;
in step 2, the unilateral gap between the shaft neck of the male rotor and the bearing bush is set as beta 1 The unilateral gap between the female rotor shaft neck and the bearing bush is beta 2 The stress angle of the male rotor is alpha when engaged 1 The stress angle of the female rotor is alpha when engaged 2 The minimum working oil film thickness of the bearing bush of the male rotor is h 1 The minimum working oil film thickness of the female rotor bearing bush is h 2 Then:
；
step 3, designing and manufacturing a male rotor and a female rotor by taking A+DeltaA as a rotor center distance;
and 4, mounting the bearing bushes by taking the center distance as A, and mounting the male and female rotors on the shell so that the shaft necks of the rotors are in sliding fit with the corresponding bearing bushes.
2. The method of reducing screw rotor backlash as recited in claim 1, wherein: in step 3, when designing the male and female rotors, the meshing gap of the rotors gradually increases from the pitch circle to the tooth tip.
3. A method of reducing screw rotor backlash as recited in claim 2, wherein: the meshing gap at the pitch circle was 0.0004 (a+. DELTA.A), and the meshing gap at the tooth tip was 0.0008 (a+. DELTA.A).
4. A method of reducing screw rotor backlash as claimed in any one of claims 1 to 3, wherein: the molded line of the rotor is a unilateral molded line, namely a female rotor molded line is arranged in a female rotor pitch circle, and a male rotor molded line is arranged outside a male rotor pitch circle;
or double-sided molded lines, namely molded lines of the female rotor are distributed on two sides of a pitch circle of the female rotor, and molded lines of the male rotor are distributed on two sides of the pitch circle of the male rotor.
5. A method of reducing screw rotor backlash as claimed in any one of claims 1 to 3, wherein: let the number of teeth of the male rotor be Z1 and the number of teeth of the female rotor be Z2, then the values of Z1 and Z2 need to satisfy the following conditions at the same time:
(1) Z2—z1=0 or 1 or 2 or 3;
(2) Z1 is a positive integer between 2 and 8.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210655826.6A CN114992122B (en) | 2022-06-11 | 2022-06-11 | Method for reducing meshing gap of screw rotor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210655826.6A CN114992122B (en) | 2022-06-11 | 2022-06-11 | Method for reducing meshing gap of screw rotor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114992122A CN114992122A (en) | 2022-09-02 |
| CN114992122B true CN114992122B (en) | 2023-12-26 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210655826.6A Active CN114992122B (en) | 2022-06-11 | 2022-06-11 | Method for reducing meshing gap of screw rotor |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5799294A (en) * | 1980-12-10 | 1982-06-19 | Hitachi Ltd | Screw fluid machine |
| US4952125A (en) * | 1988-04-06 | 1990-08-28 | Hitachi, Ltd. | Nonlubricated screw fluid machine |
| US5364250A (en) * | 1992-09-18 | 1994-11-15 | Hitachi, Ltd. | Oil-free screw compressor and method of manufacture |
| JPH084675A (en) * | 1994-06-22 | 1996-01-09 | Hitachi Ltd | Screw compressor |
| CN2292185Y (en) * | 1996-03-29 | 1998-09-23 | 滕炳炎 | Gapless gear speed reducing box |
| CN1760552A (en) * | 2005-11-21 | 2006-04-19 | 西安交通大学 | Method for designing molded lines of rotor of helical lobe compressor |
| CN109578564A (en) * | 2018-12-06 | 2019-04-05 | 常州天山重工机械有限公司 | The method of adjustment of gear assembly sideshake and the calculation method of transverse tooth thickness stock removal |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE1018589A3 (en) * | 2009-10-08 | 2011-04-05 | Atlas Copco Airpower Nv | METHOD FOR AXIALLY POSITIONING BEARINGS AT AN END |
-
2022
- 2022-06-11 CN CN202210655826.6A patent/CN114992122B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5799294A (en) * | 1980-12-10 | 1982-06-19 | Hitachi Ltd | Screw fluid machine |
| US4952125A (en) * | 1988-04-06 | 1990-08-28 | Hitachi, Ltd. | Nonlubricated screw fluid machine |
| US5364250A (en) * | 1992-09-18 | 1994-11-15 | Hitachi, Ltd. | Oil-free screw compressor and method of manufacture |
| JPH084675A (en) * | 1994-06-22 | 1996-01-09 | Hitachi Ltd | Screw compressor |
| CN2292185Y (en) * | 1996-03-29 | 1998-09-23 | 滕炳炎 | Gapless gear speed reducing box |
| CN1760552A (en) * | 2005-11-21 | 2006-04-19 | 西安交通大学 | Method for designing molded lines of rotor of helical lobe compressor |
| CN109578564A (en) * | 2018-12-06 | 2019-04-05 | 常州天山重工机械有限公司 | The method of adjustment of gear assembly sideshake and the calculation method of transverse tooth thickness stock removal |
Non-Patent Citations (1)
| Title |
|---|
| 螺杆式水蒸气压缩机在极限工况下齿间间隙的计算方法;缪会军;张超;白单英;段亚岐;剧成成;制冷与空调;第19卷(第2期);第80-83、88页 * |
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| CN114992122A (en) | 2022-09-02 |
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