CN107677558B - Device and method for testing torsional rigidity of radial section of piston ring - Google Patents

Device and method for testing torsional rigidity of radial section of piston ring Download PDF

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CN107677558B
CN107677558B CN201710783442.1A CN201710783442A CN107677558B CN 107677558 B CN107677558 B CN 107677558B CN 201710783442 A CN201710783442 A CN 201710783442A CN 107677558 B CN107677558 B CN 107677558B
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piston ring
base
pressing body
displacement sensor
loading
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CN107677558A (en
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卢熙群
罗江龙
董庆兵
赵滨
李彤阳
王乃昆
张亮
吕修颐
何山
焦博文
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Harbin Engineering University
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    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N3/00—Investigating strength properties of solid materials by application of mechanical stress
    • G01N3/22—Investigating strength properties of solid materials by application of mechanical stress by applying steady torsional forces

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Abstract

The invention belongs to the field of power machinery, and particularly provides a torsional rigidity testing device for a radial section of a piston ring, which comprises: the device comprises a piston ring, a base, a pressing body, a force sensor, a loading handle, a leveling swing rod, a plumb, a displacement measuring swing rod, a first displacement sensor and a second displacement sensor; the base is provided with a groove, and the center of the groove of the base is provided with a central upright post; the central upright post is sequentially provided with a loading handle, a force sensor and a pressing body from top to bottom; the piston ring is arranged between the side surface of the pressing body and the inner wall of the groove of the base, and the circumferential section of the piston ring is vertical to the central upright post; the top end of the base is provided with a connecting rod, and the connecting rod is provided with a leveling swing rod and a displacement measuring swing rod; the first displacement sensor is arranged between the displacement measuring swing rod and the upper surface of the pressing body; the second displacement sensor is arranged between the side surface of the pressure body and the inner wall of the groove of the base. The invention considers the deformation of the radial section of the piston ring, has high torque measurement precision of the piston ring, and can obtain accurate torsional rigidity of the radial section of the piston ring.

Description

Device and method for testing torsional rigidity of radial section of piston ring
Technical Field
The invention relates to a piston ring in the field of power, in particular to a torsional rigidity testing device for a radial section of the piston ring and a torsional rigidity testing method for the radial section of the piston ring.
Background
The movement of the piston ring in the ring groove is very complex, with axial reciprocation, circumferential rotation, and twisting around the circumferential section. Due to the difference of gas pressure between the adjacent ring grooves and the ring land of the piston ring, the cross section of the piston ring is distorted and deformed, and then the distortion stress is generated. The torsional movement of the piston around a radial section can cause fatigue and damage to the piston ring and can also affect the air tightness of the piston ring, so that the calculation and analysis of the torsional movement of the piston ring are important. The torsional rigidity of the piston ring is a basic parameter for the dynamics and statics calculation analysis of the piston ring, and the test of the torsional rigidity of the piston ring has profound engineering significance. The invention aims to solve the technical problem of measuring the torsional rigidity of the radial section of a piston ring.
The torsional rigidity of the radial section of the existing piston ring is calculated based on a torsional rigidity calculation formula of a rectangular section on the assumption that the section of the piston ring is an ideal rectangle. A typical document is Tao He and et al, thermodynamic furniture Life Prediction for a Marine diene Engine Pitton conditioning dynamics, Advances in Mechanical Engineering, 2014. However, in practice, the radial cross section of the piston ring is not perfectly rectangular, and the material of the piston ring itself is not isotropic, and the piston ring undergoes slight local deformation at the contact portion. These factors cause certain errors in the calculation result of the torsional rigidity of the radial section of the existing piston ring.
Because the torsional motion of the piston ring is calculated more complexly, most students do not consider the torsional motion of the piston ring when researching the mechanical property of the piston ring. In addition, the application of piston ring torque and the twist angle are difficult to achieve with accurate measurements.
Disclosure of Invention
The invention aims to provide a device for testing torsional rigidity of a radial section of a piston ring, which can accurately measure the torque and the torsional angle of the piston ring and has higher precision. The invention also aims to provide a torsional rigidity testing method for the radial section of the piston ring.
The invention relates to a torsional rigidity testing device for a radial section of a piston ring, which comprises: the device comprises a piston ring, a base, a pressing body, a force sensor, a loading handle, a leveling swing rod, a plumb, a displacement measuring swing rod, a first displacement sensor and a second displacement sensor;
the base is provided with a groove, the inner wall of the groove of the base is an annular inclined plane, the center of the groove of the base is provided with a central upright post, and the central upright post is fixedly connected with the base; the central upright post is sequentially provided with a loading handle, a force sensor and a pressing body from top to bottom; the side surface of the pressing body is an annular inclined surface; the piston ring is arranged between the side surface of the pressing body and the inner wall of the groove of the base, and the circumferential section of the piston ring is vertical to the central upright post;
a connecting rod is arranged at the top end of one side of the base, and a leveling swing rod and a displacement measuring swing rod are arranged on the connecting rod; the leveling swing rod is connected with the plumb; the first displacement sensor is arranged between the displacement measuring swing rod and the upper surface of the pressing body and is vertical to the displacement measuring swing rod and the upper surface of the pressing body; the second displacement sensor is arranged between the side surface of the pressing body and the inner wall of the groove of the base and is vertical to the side surface of the pressing body and the inner wall of the groove of the base;
the present invention may further comprise:
1. and a rough coating is coated on the inner wall of the groove of the base.
2. A gasket is arranged between the loading handle and the force sensor.
3. The bottom of the base is provided with 4 symmetrical mounting holes.
The invention discloses a torsional rigidity testing method of a radial section of a piston ring, which comprises the following steps:
mounting a piston ring, and enabling a pressing body to be in contact with the surface of the piston ring by rotating a loading handle; adjusting the first displacement sensor to be vertical to the positions of the displacement measuring swing rod and the upper surface of the pressing body, and adjusting the second displacement sensor to be vertical to the side surface of the pressing body and the inner wall of the groove of the base;
recording the reading x of the first displacement sensor1Recording the reading h of the second displacement sensor0Index f of force sensor1；
Thirdly, rotating the loading wrench to carry out first loading, and recording the number x of the first displacement sensor2Index f of force sensor2；
Rotating the loading spanner to carry out second loading, and recording the index x of the first displacement sensor3Index f of force sensor3；
Step five, respectively calculating the torsion angles ∠ a and ∠ b of the piston ring after the first loading and the second loading;
Figure GDA0001480158740000021
Figure GDA0001480158740000022
wherein p is the height of the piston ring in the circumferential direction, q is the width of the section of the piston ring, m is the compensation displacement of the second displacement sensor relative to the boundary of the pressing body and the inner wall of the groove of the base due to the size of the second displacement sensor, and ∠ d is the included angle between the central upright post and the perpendicular line of the second displacement sensor.
Step six, respectively calculating the piston ring torque M after the first loading and the second loading1、M2；
Figure GDA0001480158740000023
Figure GDA0001480158740000024
∠ c is the angle between the ring pressure of the pressing body and the horizontal direction, D is the inner diameter of the piston ring, and T0 is the piston ring gap.
Step seven, calculating the torsional rigidity K of the radial section of the piston ring
Figure GDA0001480158740000031
And step eight, repeating the step one to the step seven for 3-5 times, and then calculating the average value of the torsional rigidity of the radial section of the piston ring to finally obtain the torsional rigidity test result of the radial section of the piston ring.
The invention has the following beneficial effects:
1. the device of the invention extrudes the gasket by rotating the central handle to move downwards, and the gasket extrudes the upper boundary of the inner side of the piston ring through the pressing body. The piston ring rotates around the inner side with the lower boundary of the outer side as a fulcrum. The compression load of the compression body is measured by the gasket and the middle force sensor. Therefore, the torque precision of the piston ring is high through the geometrical relation calculation.
2. The displacement of the downward movement of the pressing body can be tested by the first displacement sensor. The coarse coating improves the fixing effect of the groove testing area of the base, and the outer boundary of the piston ring is not easy to slide.
The distance between the boundary of the pressing platform and the inner wall of the groove of the base at the initial moment can be obtained through the second displacement sensor. The rotation angle of the upper boundary around the outer lower fulcrum inside the piston ring can be accurately obtained by combining the geometric structure calculation formula of the testing device.
3. The invention is easy to carry out a plurality of tests, and the accurate torsional rigidity of the radial section of the piston ring can be obtained by carrying out statistical analysis on the torque and the torsional angle obtained by the plurality of tests.
4. The invention has convenient loading and high testing efficiency; the data acquisition precision is high; the structure is simple, and the manufacture is convenient; is suitable for various piston ring sections and has wide application range.
Drawings
FIG. 1 is a schematic view of the apparatus of the present invention;
fig. 2 is a schematic view of torsional deformation of a piston ring section.
Detailed Description
The apparatus will be described in detail with reference to fig. 1 to 2. A torsional rigidity testing device for a radial section of a piston ring.
The object of the invention is achieved by comprising: the device comprises a piston ring 6, a base 8, a pressing body 5, a force sensor 4, a loading handle 3, a leveling swing rod 10, a plumb 11, a displacement measuring swing rod 12, a first displacement sensor 13 and a second displacement sensor 14;
the base 8 is provided with a groove, the inner wall of the groove of the base is an inclined plane which is circumferentially symmetrical, the center of the groove of the base is provided with a central upright post 1, and the central upright post 1 is fixedly connected with the base 8; the central upright post 2 is sequentially provided with a loading handle 3, a force sensor 4 and a pressing body 5 from top to bottom; the side surface of the pressing body 5 is an inclined plane which is circumferentially symmetrical; the piston ring 6 is arranged between the side surface of the pressing body and the inner wall of the groove of the base, and the circumferential section of the piston ring is vertical to the central upright post 1;
a connecting rod is arranged at the top end of one side of the base, and a leveling swing rod 10 and a displacement measuring swing rod 12 are arranged on the connecting rod; the leveling swing rod is connected with the plumb 11; the first displacement sensor 13 is arranged between the displacement measuring swing rod 12 and the upper surface of the pressing body 5; the second displacement sensor 14 is arranged between the side surface of the pressing body and the inner wall of the groove of the base;
the inner wall of the groove of the base is coated with a rough coating 7.
A gasket 2 is arranged between the loading handle and the force sensor.
The bottom of the base is provided with 4 symmetrical mounting holes 9.
The base 8 is rigidly mounted to a horizontal base surface through 4 mounting holes around it. The piston ring 6 is horizontally placed in a groove of a base 8, the piston ring is placed in the area where the rough coating 7 is located, the leveling swing rod 10 is rotated, whether the upper plane of the piston ring is horizontal or not is detected through the plumb 11 on the upper plane, and if the upper plane is not horizontal, adjustment is carried out. The press body 5 is then moved down through the central upright 1 into contact with the piston ring 6. And then the force sensor 4, the gasket 2 and the loading handle 3 are sequentially arranged through the central upright post. The loading handle 3 is rotated to make the piston ring fully contact with the pressing body; the central upright post 1 is provided with threads, and the piston ring 6 is loaded by further rotating the loading handle 3.
In the prior art, a formula is calculated according to the torsional rigidity of a rectangular section, namely formula (1) for the torsional rigidity K of the rectangular section of a piston ringrtAnd (6) performing calculation.
Figure GDA0001480158740000041
In the formula: d is the outer diameter of the piston ring; d is the inner diameter of the piston ring; e is the elastic modulus of the piston ring; b is the axial height of the piston ring.
In practice, the cross section of the piston ring is not perfectly rectangular, and the material of the piston ring itself is not isotropic, and the piston ring is slightly deformed locally at the contact portion. These factors make the calculation of this formula somewhat different from the actual torsional stiffness.
The method for testing the torsional rigidity of the radial section of the piston ring by using the device comprises the following steps: rotary displacement measurementThe rocker 12 and the position of the first displacement sensor 13 on the displacement measuring rocker are adjusted to correspond to the sensor receiver. The test is started and the reading x of the first displacement sensor 13 is recorded1Similarly, the second displacement sensor 14 is adjusted and its reading is recorded as h0Indication f of the force sensor 41. The loading wrench 3 is rotated by a certain angle for loading, and the number x of the first displacement sensor 13 is recorded2Indication f of the force sensor 42(ii) a Then repeating the above operation by the same method to obtain x3,f3。
As can be seen from fig. 2, a diagonal line AB of the piston ring cross section is subjected to two loads to reach positions AE and AG, respectively, where AB is AE AG, ∠ a and ∠ b are torsion angles after the two loads, respectively, and S is obtained from formulas (2) and (3)1、S2。
S1＝x2-x1(2)
S2＝x3-x2(3)
From the height p in the circumferential direction of the piston ring and the width q of the cross section, the distance AB of the piston ring diagonal line can be obtained by the formula (3).
Figure GDA0001480158740000051
The lengths BC, ED and GF are obtained by the formulas (4), (5) and (6) respectively, wherein m is the compensation displacement of the second displacement sensor relative to the boundary of the loading pressure body and the inner wall of the groove of the base due to the size of the second displacement sensor, and ∠ d is the included angle between the central upright post and the vertical line of the second displacement sensor.
BC＝h0+m (5)
ED＝BC-S1·cos(∠d) (6)
GF＝ED-S2·cos(∠d) (7)
The corresponding ∠ BAC, ∠ EAD, ∠ GAF are obtained from the formulas (8), (9), (10)
∠BAC＝arcsin(BC/AB) (8)
∠EAD＝arcsin(ED/AB) (9)
∠GAF＝arcsin(GF/AB) (10)
Then obtaining corresponding torsion angles ∠ a, ∠ b from formulas (11), (12)
∠a＝∠BAC-∠EAD (11)
∠b＝∠BAC-∠GAF (12)
Then, the corresponding torques M1 and M2 are obtained by the readings of the force sensors and the relevant dimensional parameters of the structure, and the circumferential length L of the piston ring is obtained by the formula (11) through the piston ring inner diameter D and the piston ring gap T0.
L＝πD-T0 (13)
Arm lengths AD and AF of piston rings at AE and AG are obtained from formulas (14) and (15)
Figure GDA0001480158740000052
Figure GDA0001480158740000053
The expressions (16) and (17) respectively obtain the moments M of the piston rings at AE and AG1、M2∠ c is the angle between the ring pressure of the pressing body and the horizontal direction, and ∠ c + ∠ d is 90 °.
Figure GDA0001480158740000054
Figure GDA0001480158740000061
Finally, the corresponding torsional rigidity K is obtained from the formula (18)
Figure GDA0001480158740000062
And respectively testing for 3-5 times by the same method and then obtaining corresponding average values to obtain the torsional rigidity corresponding to the piston ring. Those skilled in the art can adopt other embodiments without departing from the spirit of the invention.

Claims (6)

1. A piston ring radial cross section torsional rigidity testing arrangement includes: the device comprises a piston ring, a base, a pressing body, a force sensor, a loading handle, a leveling swing rod, a plumb, a displacement measuring swing rod, a first displacement sensor and a second displacement sensor; the device is characterized in that a groove is formed in the base, the inner wall of the groove of the base is an annular inclined plane, a central upright post is arranged in the center of the groove of the base, and the central upright post is fixedly connected with the base; the central upright post is sequentially provided with a loading handle, a force sensor and a pressing body from top to bottom; the side surface of the pressing body is an annular inclined surface; the piston ring is arranged between the side surface of the pressing body and the inner wall of the groove of the base, and the circumferential section of the piston ring is vertical to the central upright post;
the top end of the base is provided with a connecting rod, and the connecting rod is provided with a leveling swing rod and a displacement measuring swing rod; the leveling swing rod is connected with the plumb; the first displacement sensor is arranged between the displacement measuring swing rod and the upper surface of the pressing body and is vertical to the displacement measuring swing rod and the upper surface of the pressing body; the second displacement sensor is arranged between the side surface of the pressing body and the inner wall of the groove of the base and is perpendicular to the side surface of the pressing body and the inner wall of the groove of the base.
2. The apparatus for testing torsional rigidity of a radial section of a piston ring according to claim 1, wherein a rough coating is applied to an inner wall of a groove of the base.
3. A piston ring radial cross-section torsional stiffness test apparatus as claimed in claim 1 or 2, wherein a spacer is provided between the loading handle and the force sensor.
4. A torsional rigidity tester for a radial section of a piston ring as claimed in claim 1 or 2, wherein the base has 4 symmetrical mounting holes at the bottom.
5. A piston ring radial cross-section torsional stiffness test apparatus as claimed in claim 3, wherein the base has 4 symmetrical mounting holes in the bottom.
6. A method for testing torsional rigidity of a radial section of a piston ring by using the device of claim 1, which comprises the following steps:
mounting a piston ring, and enabling a pressing body to be in contact with the surface of the piston ring by rotating a loading spanner; adjusting the first displacement sensor to be vertical to the positions of the displacement measuring swing rod and the upper surface of the pressing body, and adjusting the second displacement sensor to be vertical to the side surface of the pressing body and the inner wall of the groove of the base;
recording the reading x of the first displacement sensor1Recording the reading h of the second displacement sensor0Index f of force sensor1；
Thirdly, rotating the loading wrench to carry out first loading, and recording the number x of the first displacement sensor2Index f of force sensor2；
Rotating the loading spanner to carry out second loading, and recording the index x of the first displacement sensor3Index f of force sensor3；
Step five, respectively calculating the torsion angles ∠ a and ∠ b of the piston ring after the first loading and the second loading;
the calculated expression of the involved piston ring torsional angles ∠ a and ∠ b is
Figure FDA0002299787190000021
Figure FDA0002299787190000022
Wherein p is the height of the piston ring in the circumferential direction, q is the width of the section of the piston ring, m is the compensation displacement of the second displacement sensor relative to the boundary of the pressure body and the inner wall of the groove of the base due to the size of the second displacement sensor, and ∠ d is the included angle between the central upright post and the vertical line of the second displacement sensor;
step six, respectively calculating the piston ring torque M after the first loading and the second loading1And M2；
Relating to the piston ring torque M1And M2Is calculated as
Figure FDA0002299787190000023
Figure FDA0002299787190000024
Wherein ∠ c is the angle between the ring pressure of the pressing body and the horizontal direction, D is the inner diameter of the piston ring, and T0 is the clearance of the piston ring;
step seven, calculating the torsional rigidity K of the radial section of the piston ring;
the calculation expression of the torsional rigidity K of the radial section of the piston ring is
Figure FDA0002299787190000025
And step eight, repeating the step one to the step seven for 3-5 times, and then calculating the average value of the torsional rigidity of the radial section of the piston ring to finally obtain the torsional rigidity test result of the radial section of the piston ring.
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CN108414437A (en) * 2018-03-15 2018-08-17 哈尔滨工程大学 A kind of piston ring hydraulic loading device
CN109100244B (en) * 2018-07-26 2020-12-18 中国航空工业集团公司沈阳飞机设计研究所 Parameter selection test method for torsion spring for airplane
RU2727211C1 (en) * 2019-07-29 2020-07-21 Публичное акционерное общество Научно-производственное объединение "Искра" Device for testing strength of reinforcing plates of elastic nozzle hinge of solid-propellant rocket engine
CN112857647B (en) * 2021-03-25 2023-01-03 哈尔滨工程大学 Piston ring circumference elasticity detection device
CN114018726B (en) * 2021-10-22 2023-11-21 中国空空导弹研究院 Piano spring type torque loading device with adjustable rigidity

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JPS59178333A (en) * 1983-03-29 1984-10-09 Nippon Piston Ring Co Ltd Twist testing method of piston ring
CN200961533Y (en) * 2006-10-21 2007-10-17 安徽江淮汽车股份有限公司 Piston ring of diesel engine
CN102519809B (en) * 2011-12-31 2014-04-02 浙江省三门县世泰实业有限公司 Material torsion testing machine
CN103234818B (en) * 2013-04-28 2015-05-06 长城汽车股份有限公司 Clamping device for testing torsional rigidity of shaft sleeve
CN205719911U (en) * 2016-05-12 2016-11-23 哈尔滨工程大学 One can continually varying piston ring domain machinery loading device

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