CN213117359U - Lightweight involute gear pump for aerospace - Google Patents
Lightweight involute gear pump for aerospace Download PDFInfo
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- CN213117359U CN213117359U CN202020105665.XU CN202020105665U CN213117359U CN 213117359 U CN213117359 U CN 213117359U CN 202020105665 U CN202020105665 U CN 202020105665U CN 213117359 U CN213117359 U CN 213117359U
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Abstract
The utility model discloses a lightweight involute gear pump for space flight, including the action wheel and rather than constituting meshing motion's the identical from the driving wheel, the action wheel is with the profile from the driving wheel: the semi-gear profile is arranged through a structure of circumferential array operation after mirror image operation, the semi-gear profile is composed of 4 sections of profile sections which are connected end to end, namely tooth crest arc sections (12), top transition arc sections (23), involute profile sections (34) and root transition arcs (45). The technology aims to meet the performance requirement of the involute gear pump, and adopts a reverse flow opposite to the prior forward flow, takes the contact ratio and the tooth number which can most reflect the performance of the involute gear pump as direct parameters of tooth profile construction, and maximizes the shape coefficient and the modulus on the premise of maximizing the shape coefficient, thereby realizing the lightweight performance requirement of the aerospace pump, and the method is simple.
Description
Technical Field
The utility model relates to a gear pump, in particular to light-weight involute gear pump for spaceflight.
Background art:
the gear pump is a hydraulic element for pumping working media, is widely applied and is also applied to a water treatment system and a thermal control system of a large-scale spacecraft, the high launching cost of the spaceflight puts higher requirements on the lightweight performance of the pump, a gear pair consisting of a pair of identical gears is a core component of the pump, and the design quality of profile parameters (tooth profile parameters for short) of the gear pair directly influences the performance of the pump. The existing research shows that the lightweight degree of the pump depends on the maximum degree of the radius of the addendum circle of the gear, and the larger the radius of the addendum circle is, the better the lightweight performance of the pump is.
Among various transmission forms, the application of involute gear transmission is the most common, so that a large number of standards are established at home and abroad to standardize the design and processing of the involute gear transmission, and the standardized contents are general basic parameters of tooth profile structures such as modulus, tooth number, displacement coefficient, addendum coefficient and the like.
The pump gear is used as a special application of the gear on a pump, and the design method of the conventional multi-continuation standard gear is a forward flow which is formed by working condition parameters of rated rotating speed, rated pressure and rated flow → basic parameters of designed pump tooth profile → checking of performance requirements of pump volumetric efficiency, flow pulsation, transmission, cavitation and the like. The process is an iterative process until the designed basic parameters can completely meet the performance requirements of the pump, and therefore, the design efficiency is relatively low.
The basic parameters are set originally for designing and processing the 'standard' involute gear, but the basic parameters cannot directly reflect the special requirements of the pump performance, and according to the existing forward flow, the contact ratio, the tooth crest angle, the shape coefficient and the like which can most reflect the requirements of the pump performance are summarized as indirect parameters of the tooth profile.
With the rapid development of modern manufacturing technology, the machining of few teeth and no undercut of the gear for the pump is not a problem for a long time.
The involute gear pump for spaceflight mainly relates to the performance requirement that (1) the minimum addendum half angle sigma is limited by a radial sealmin(ii) a (2) A contact ratio epsilon of 1.05-1.15 defined by stable transmission and the like; (3) minimum number of teeth z required by the pulsation mass; (4) maximum tip peripheral speed v defined by pump cavitation performancemax(ii) a (5) The lightweight performance requires a maximum degree of the radius of the addendum circle.
The prior research shows that the weight reduction of the pump depends on the radius r of the top circle of the gearaMaximum of, and "tip radius raThe pump weight reduction is equivalent to r maximization under the premise of λ maximization, namely the shape coefficient λ × the pitch circle radius r ″; and r is "0.5 m × z × cos αn,/cos α ", reference circle pressure angle α with λ maximized and minimum number of teeth z required for pulse qualitynThe pitch circle pressure angle α and the number of teeth z, which is the minimum number of teeth required by the pulse mass, are each determined values. The degree of pump lightening is then again equivalent to the maximization of the modulus m on the premise of the maximization of λ.
The maximum degree of lambda is determined by that the addendum half angle sigma is more than or equal to sigmaminZ and epsilon are determined jointly by 1.05-1.15, and sigma is directly calculated by the exact avoidance relation between the gear pairs; the modulus m is maximized by the addendum circumferential velocity v ″ - λ r × pi n/30 ″ -being less than vmaxDetermined that n is the rated rotation speed vmaxDetermined by the viscosity of the medium. Then, ε, z, σmin、vmaxAnd n are five independent parameters predetermined by the invention.
Disclosure of Invention
Aiming at the special application requirements of the gear of the pump for the spaceflight, a reverse flow opposite to the forward flow is adopted, the actual requirements of the pump performance are completely met, so-called 'indirect parameters' which can most embody the pump performance are taken as direct construction parameters of the tooth profile, and the direct construction parameters are the key points of the lightweight involute tooth profile construction and the reverse design of the pump for the spaceflight.
The utility model provides an involute gear pump for space flight, includes action wheel and constitutes the identical driven wheel of meshing motion rather than it, the profile of action wheel and driven wheel is: the half-gear profile is set through a structure of circumferential array operation after mirror image operation, and the half-gear profile consists of 4 sections of profile sections which are connected end to end and are composed of an addendum arc section 12, a top transition arc section 23, an involute profile section 34 and a root transition arc 45;
wherein, the point 4 of the involute profile section 34 is located on a base circle, which is called a tooth base point, namely, the gear has the capacity of limit meshing;
the end point 1 of the addendum arc section 12 is located on a tooth symmetry axis, and the end point 2 of the addendum arc section 12 is located on an outward extending involute of the involute profile section 34, which is called as an addendum point, so that the maximization of the shape coefficient lambda is further realized on the basis of the limit meshing capability;
wherein the top transition circular arc section 23 is uniquely determined by three geometric conditions of passing through the tooth top point 2, being vertical to the tooth top circular arc section 12 and passing through the tooth profile point 3, the top transition circular arc section 23 is constructed to completely avoid the tooth base point 4,
the root transition arc 45 is uniquely determined by three geometric conditions of a tooth passing base point 4, a circumscribed root circle at a point 5 and a circle center on a symmetry axis of the tooth socket.
Preferably, the top transition arc segment 23 and the root transition arc 45 are shaped as follows: the transition circular arc section can be processed by a simple drilling method.
Further, the tooth profile shape and size are reversely determined by the following steps:
step one, the forming principle of the involute profile section 34 and the point 4 are positioned on a base circle to obtain
α4＝0；
Wherein alpha is a pitch circle pressure angle alpha4Is the pressure angle at the tooth base point 4, at which time the involute profile segment 34 has a limit position on the profile, ε is the contact ratio of the gear drive, z is the number of teeth;
step two, the pressure angle at the tooth profile point 3 on the involute profile section 34 is obtained by the definition of the contact ratio of the gear pair when the driving wheel and the driven wheel are completely the same
Step three, the peak 2 of the upper tooth of the driven wheel just avoids the extreme position of the base point 4 of the upper tooth of the driving wheel, and the final result is obtained
Wherein, from the involute forming principle
Wherein alpha is2Is the pressure angle at the addendum point 2,
the angle rotated by the gear is determined by taking the time when the driven wheel top shaft and the driving wheel root shaft are superposed on the central connecting line as the initial position and just avoiding the limit position of the driving wheel tooth base point 4 from the driven wheel tooth top point 2; σ is the central angle corresponding to the addendum arc segment 12, i.e. the addendum half-angle, and has a lower limit value σ in view of the radial sealing requirement of the regionminAnd τ is the central angle corresponding to the root transition arc 45.
And the addendum point 2 is positioned on the external extending involute of the involute profile section 34 to obtain
The three equations of the joint type (3) - (5) can be uniquely obtained
α2(ε, z) and σ (ε, z);
step four, if sigma (epsilon, z) gtoreqsigmaminThen σ (ε, z) and α2(ε, z) directly using step threeThe calculated value of (a);
otherwise, take σ (ε, z) as σminAnd, the formula (5) recalculates α2(ε，z)；
Step five, defining the maximum shape coefficient as
Step six, obtaining alpha from the above2、α3And alpha4The construction method of 0, 23 and 45 transition circular arc segments can completely determine the shape of the half-gear profile, the size of the half-gear profile depends on the size of the pitch circle radius, and the size of the pitch circle radius depends on the size of the modulus; the modulus is determined by the maximum allowable circumferential speed of the tooth top without causing cavitation and the standard value specified by the national standard, that is to say
In the formula, vmaxMaximum peripheral speed allowed for tooth tips, m/s; n is rated rotating speed, r/min; alpha is alphanThe pressure angle of the reference circle is 20 degrees; SD () represents the standard value specified by the national standard for modulus.
Step seven, the gear pair composed of the identical driving wheel and the driven wheel has the corresponding deflection mode of angle deflection, and the corresponding deflection coefficient x and the tooth crest height coefficient h are
Then obtaining the basic parameters of the gear such as modulus, tooth number, displacement coefficient and tooth crest height coefficient.
The invention has the beneficial effects that:
in the invention, in the meshing motion of the driving wheel and the driven wheel, the top transition circular arc section 23 is constructed to completely avoid the tooth base points 4. The invention aims to meet the performance requirement of the involute gear pump, adopts a reverse flow opposite to the prior forward flow, takes the contact ratio and the tooth number which can most reflect the performance of the involute gear pump as direct parameters of tooth profile structure, and maximizes the shape coefficient and the modulus based on the shape coefficient, thereby realizing the lightweight performance requirement of the aerospace pump.
Drawings
FIG. 1 is a schematic half-gear profile view of a gear.
Fig. 2 is a schematic diagram of a limit structure that the tooth top point 2 on the driven wheel just avoids the tooth base point 4 on the driving wheel.
Detailed Description
The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.
As shown in fig. 1-2, an involute gear pump for aerospace use comprises a driving wheel and a driven wheel which are completely the same and form a meshing motion with the driving wheel, wherein the driving wheel and the driven wheel have profiles of a configuration that half gear profiles operate in a circumferential array after mirror image operation, and the half gear profiles comprise addendum circular arc segments 12(12 represents an arc segment between a point 1 and a point 2 in the drawing), top transition circular arc segments 23(23 represents an arc segment between a point 2 and a point 3 in the drawing), involute profile segments 34(34 represents a profile segment between a point 3 and a point 4 in the drawing), and root transition circular arcs 45(45 represents an arc between a point 4 and a point 5 in the drawing) to form 4 profile segments which are connected end to end;
wherein, the point 4 of the involute profile section 34 is located on a base circle, which is called a tooth base point, namely, the gear has the capacity of limit meshing;
the end point 1 of the tooth top arc section 12 is located on a tooth symmetry axis, and the end point 2 of the tooth top arc section 12 is located on an outward extending involute of the involute profile section 34, which is called a tooth top point, so that the maximization of the shape coefficient lambda is further realized on the basis of the limit meshing capability;
wherein the top transition circular arc section 23 is uniquely determined by three geometric conditions of passing through the tooth top point 2, being vertical to the tooth top circular arc section 12 and passing through the tooth profile point 3, the top transition circular arc section 23 is constructed to completely avoid the tooth base point 4,
the root transition arc 45 is uniquely determined by three geometric conditions of a tooth passing base point 4, a circumscribed root circle at a point 5 and a circle center on a symmetry axis of the tooth socket.
Preferably, the top transition arc segment 23 and the root transition arc 45 are shaped as follows: the transition circular arc section can be processed by a simple drilling method.
Further, the tooth profile shape and size are reversely determined by the following steps:
step one, the forming principle of the involute profile section 34 and the point 4 are positioned on a base circle to obtain
α4＝0；
Wherein alpha is a pitch circle pressure angle alpha4Is the pressure angle at the tooth base point 4, at which point the involute profile segment 34 has an extreme position on the profile;
step two, the pressure angle at the tooth profile point 3 on the involute profile section 34 is obtained by the definition of the contact ratio of the gear pair when the driving wheel and the driven wheel are completely the same
Step three, the peak 2 of the upper tooth of the driven wheel just avoids the extreme position of the base point 4 of the upper tooth of the driving wheel, and the final result is obtained
Wherein, from the involute forming principle
Wherein alpha is2Is the pressure angle at the addendum point 2,
the angle rotated by the gear is determined by taking the time when the driven wheel top shaft and the driving wheel root shaft are superposed on the central connecting line as the initial position and just avoiding the limit position of the driving wheel tooth base point 4 from the driven wheel tooth top point 2; σ is the central angle corresponding to the addendum arc segment 12, i.e. the addendum half-angle, and has a lower limit value σ in view of the radial sealing requirement of the regionminAnd τ is the central angle corresponding to the root transition arc 45.
And the addendum point 2 is positioned on the external extending involute of the involute profile section 34 to obtain
The three equations of the joint type (3) - (5) can be uniquely obtained
α2(ε, z) and σ (ε, z);
step four, if sigma (epsilon, z) gtoreqsigmaminThen σ (ε, z) and α2(epsilon, z) directly adopting the calculated value in the third step;
otherwise, take σ (ε, z) as σminAnd, the formula (5) recalculates α2(ε，z)；
Step five, defining the maximum shape coefficient as
Step six, obtaining alpha from the above2、α3And alpha40, 23 and 45 transition arc segment,the shape of the half-gear profile can be completely determined, and the size of the half-gear profile depends on the size of the pitch circle radius, which depends on the size of the modulus; the maximum determination of the modulus is limited primarily by the upper modulus limit determined by the maximum tip peripheral speed and the standardization of the "norm", i.e. the upper modulus limit determined by the maximum tip peripheral speed, which does not cause cavitation, i.e. the normalization
In the formula, vmaxMaximum peripheral speed allowed for tooth tips, m/s; n is rated rotating speed, r/min; alpha is alphanThe pressure angle of the reference circle is 20 degrees; SD () represents the standard value specified by the national standard for modulus.
Step seven, the gear pair composed of the identical driving wheel and the driven wheel has the corresponding deflection mode of angle deflection, and the corresponding deflection coefficient x and the tooth crest height coefficient h are
Then obtaining the basic parameters of the gear such as modulus, tooth number, displacement coefficient and tooth crest height coefficient.
The first embodiment is as follows: the tooth profile structure and the reverse design method under the premise of giving five independent parameters are as follows:
measuring sigma by five independent parametersmin＝2°，ε＝1.1，z＝8，n＝1750r/min，vmax＝4.2m/s。
The utility model provides an involute gear pump for space flight, includes action wheel and constitutes the identical driven wheel of meshing motion rather than it, the profile of action wheel and driven wheel is: the half-gear profile is set by the construction of the circumferential array operation after the mirror image operation, which is characterized in that: the half-gear profile consists of 4 sections of profile sections which are connected end to end, wherein the 4 sections of profile sections are formed by an addendum circular arc section 12, a top transition circular arc section 23, an involute profile section 34 and a root transition circular arc 45; the point 4 of the involute profile segment 34 is located on a base circle, called a tooth base point, namely, the gear has the capacity of limit meshing; the end point 1 of the addendum arc section 12 is positioned on the tooth symmetry axis, and the end point 2 of the addendum arc section 12 is positioned on the outward extending involute of the involute profile section 34, which is called as an addendum point, so that the maximization of the shape coefficient lambda is further realized on the basis of the limit meshing capability; the top transition circular arc section 23 is uniquely determined by three geometric conditions of passing through an addendum point 2, being vertical to the addendum circular arc section 12 and passing through a tooth profile point 3, the top transition circular arc section 23 is constructed to completely avoid tooth base points 4, and the root transition circular arc 45 is uniquely determined by three geometric conditions of passing through the tooth base points 4, externally tangent to a root circle at a point 5 and having a circle center on a symmetry axis of a tooth socket.
The tooth profile shape and size determination scheme is as follows:
step one, the forming principle of the involute profile section 34 and the point 4 are positioned on a base circle to obtain
α4＝0；
Wherein α is a pitch circle pressure angle α4The pressure angle at the tooth base 4, at which the involute profile segment 34 has an extreme position on the profile, ε is the contact ratio of the gear transmission, and z is the number of teeth.
Step two, the pressure angle at the tooth profile point 3 on the involute profile section 34 is obtained by the definition of the contact ratio of the gear pair when the driving wheel and the driven wheel are completely the same
Step three, the peak 2 of the upper tooth of the driven wheel just avoids the extreme position of the base point 4 of the upper tooth of the driving wheel, and the final result is obtained
Wherein, from the involute forming principle
In the formula, alpha2Is the pressure angle at the addendum point 2,
the angle rotated by the gear is determined by taking the time when the driven wheel top shaft and the driving wheel root shaft are superposed on the central connecting line as the initial position and just avoiding the limit position of the driving wheel tooth base point 4 from the driven wheel tooth top point 2.
And the addendum point 2 is positioned on the external extending involute of the involute profile section 34 to obtain
The three equations of the joint type (3) to (5) are uniquely obtained
α242.65 ° and σ 2.51 °.
Step four, because sigma (epsilon, z) is 2.51 degrees and is larger than sigma min2 deg. then alpha2＝42.65°，σ＝2.51°。
Step five, defining the maximum shape coefficient as
Step six, obtaining alpha from the above2、α3And alpha4The construction method of 0, 23 and 45 transition circular arc segments can completely determine the shape of the half-gear profile, the size of the half-gear profile depends on the size of the pitch circle radius, and the size of the pitch circle radius depends on the size of the modulus; the modulus is determined by the maximum allowable circumferential speed of the tooth top without causing cavitation and the standard value specified by the national standard, that is to say
Step seven, the gear pair composed of the identical driving wheel and the driven wheel has the corresponding deflection mode of angle deflection, and the corresponding deflection coefficient x and the tooth crest height coefficient h are
Then obtaining the basic parameters of the gear with the modulus of 4, the tooth number of 8, the displacement coefficient of 0.1025 and the addendum coefficient of 1.1102 for processing.
Claims (2)
1. The utility model provides a light-weight involute gear pump for space flight, includes the action wheel and constitutes meshing motion's the identical driven wheel rather than, its characterized in that: the profiles of the driving wheel and the driven wheel are as follows: the semi-gear profile is constructed by circumferential array operation after mirror image operation, and the semi-gear profile consists of 4 sections of profile sections which are connected end to end and are formed by a tooth crest arc section, a top transition arc section, an involute profile section and a root transition arc;
the points of the involute profile section are located on a base circle, called tooth base points, namely, the gear has the capacity of limit meshing;
the end point (1) of the tooth top arc section is positioned on a tooth symmetry axis, and the end point of the tooth top arc section is positioned on an outward extending involute of the involute profile section and is called as a tooth top point (2), so that the maximization of the shape coefficient lambda is further realized on the basis of the limit meshing capacity;
wherein the top transition circular arc section is uniquely determined by three geometrical conditions of a tooth top passing point (2), a tooth top circular arc section vertical to the tooth top and a tooth profile passing point (3), the top transition circular arc section is constructed to completely avoid tooth base points (4),
the root transition arc is uniquely determined by three geometric conditions of a tooth passing base point (4), a circumscribed root circle at a point (5) and a circle center on a symmetry axis of the tooth socket.
2. The light involute gear pump for spaceflight as claimed in claim 1, wherein: the top transition arc section and the root transition arc section have the following shapes: the transition circular arc section can be processed by a simple drilling method.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111442074A (en) * | 2020-01-17 | 2020-07-24 | 宿迁学院 | Lightweight involute tooth profile structure of aerospace pump and reverse design method thereof |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111442074A (en) * | 2020-01-17 | 2020-07-24 | 宿迁学院 | Lightweight involute tooth profile structure of aerospace pump and reverse design method thereof |
| CN111442074B (en) * | 2020-01-17 | 2023-08-11 | 宿迁学院 | Lightweight involute tooth profile structure of aerospace pump and reverse design method thereof |
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Effective date of registration: 20211217 Address after: 641400 No. 8, longhui Road, Jiancheng, Jianyang, Chengdu, Sichuan Patentee after: SICHUAN WUHUAN PETROCHEMICAL EQUIPMENT Co.,Ltd. Address before: 223800 South Huanghe Road, Suqian City, Jiangsu Province, 399 Patentee before: SUQIAN College |
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