CN114689231A - Camshaft contact stress testing method - Google Patents
Camshaft contact stress testing method Download PDFInfo
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- CN114689231A CN114689231A CN202210326539.0A CN202210326539A CN114689231A CN 114689231 A CN114689231 A CN 114689231A CN 202210326539 A CN202210326539 A CN 202210326539A CN 114689231 A CN114689231 A CN 114689231A
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- rocker arm
- rocker
- camshaft
- stress
- strain
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- 238000000034 method Methods 0.000 title claims abstract description 13
- 238000009662 stress testing Methods 0.000 title claims abstract description 12
- 238000012360 testing method Methods 0.000 claims abstract description 46
- 241000406668 Loxodonta cyclotis Species 0.000 claims abstract description 35
- 238000002474 experimental method Methods 0.000 claims abstract description 5
- 238000004088 simulation Methods 0.000 claims abstract description 5
- 230000006835 compression Effects 0.000 claims description 6
- 238000007906 compression Methods 0.000 claims description 6
- 238000010998 test method Methods 0.000 claims description 4
- 238000005259 measurement Methods 0.000 description 7
- 238000006073 displacement reaction Methods 0.000 description 6
- 239000011888 foil Substances 0.000 description 6
- 238000010586 diagram Methods 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
- G01L5/0009—Force sensors associated with a bearing
- G01L5/0019—Force sensors associated with a bearing by using strain gages, piezoelectric, piezo-resistive or other ohmic-resistance based sensors
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- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Valve-Gear Or Valve Arrangements (AREA)
Abstract
The application relates to the technical field of engines, and discloses a camshaft contact stress testing method, which comprises the following steps: testing the strain of the rocker arm; testing a first relation coefficient between the stress of the elephant foot of the rocker arm and the strain of the rocker arm through experiments; calculating the actual stress of the elephant foot of the rocker arm according to the measured strain on the rocker arm and the first relation coefficient; calculating a second relation coefficient between the rocker elephant foot stress and the contact stress of the rocker roller and the camshaft through simulation or experimental test; and calculating the actual contact stress of the rocker roller and the camshaft according to the actual stress of the rocker elephant foot and the second relation coefficient. The contact stress between the camshaft and the rocker roller is indirectly tested by testing the strain of the rocker, so that the test cost can be reduced, and the test accuracy can be improved.
Description
Technical Field
The application relates to the technical field of engines, in particular to a camshaft contact stress testing method.
Background
The rocker roller of the engine is contacted with the camshaft to form a connecting pair. Because the rocker arm roller is line contact with the camshaft, and the contact pressure between the rocker arm roller and the camshaft is very large, the contact stress between the rocker arm roller and the camshaft is very large, the problems that the camshaft and the rocker arm roller are easy to peel off from the surface and the like are caused, and finally the engine cannot work. Therefore, the contact stress between the camshaft and the rocker arm roller needs to be tested at the engine prototype stage, and the contact stress between the rocker arm roller and the camshaft is ensured to be not more than the yield limit of the materials of the rocker arm roller and the camshaft.
At present, the strain gauge is mainly attached to a round corner of a camshaft, and holes are formed in the center of the camshaft, so that the rigidity of the camshaft is reduced, the test data are inaccurate, the space of the round corner of the camshaft is limited, and the strain gauge is difficult to attach. And the camshaft rotates at a high speed, a slip ring is used for connection in the middle, and the connection of the led-out signal wire is also complex, so that the test cost is increased.
Disclosure of Invention
The application aims to provide a camshaft contact stress testing method, which can effectively improve testing accuracy and reduce testing cost.
In order to solve the technical problem, the application provides the following technical scheme:
a camshaft contact stress testing method comprises the following steps:
testing the strain of the rocker arm;
testing a first relation coefficient between the stress of the elephant foot of the rocker arm and the strain of the rocker arm through experiments;
calculating the actual stress of the elephant foot of the rocker arm according to the measured strain on the rocker arm and the first relation coefficient;
calculating a second relation coefficient between the rocker elephant foot stress and the contact stress of the rocker roller and the camshaft through simulation or experimental test;
and calculating the actual contact stress of the rocker roller and the camshaft according to the actual stress of the rocker elephant foot and the second relation coefficient.
Preferably, the step of testing the strain of the rocker arm comprises:
and adhering a strain gauge on the rocker arm, and testing the strain of the rocker arm through the strain gauge.
Preferably, the strain gauge is adhered to the surface of the rocker arm near one end of the rocker arm elephant foot.
Preferably, the step of experimentally testing a first coefficient of relationship between rocker elephant foot force and rocker strain comprises:
and calculating the stress acting on the rocker arm elephant foot by testing the compression amount of a valve spring acting on the rocker arm elephant foot.
Preferably, the compression amount of the valve spring is tested while the strain of the rocker arm is tested.
Preferably, after calculating the actual contact stress between the rocker arm roller and the camshaft, a contact stress curve between the rocker arm roller and the camshaft in a preset period is obtained.
Compared with the prior art, the technical scheme has the following advantages:
the application provides a camshaft contact stress test method, including: testing the strain of the rocker arm; testing a first relation coefficient between the stress of the elephant foot of the rocker arm and the strain of the rocker arm through experiments; calculating the actual stress of the elephant foot of the rocker arm according to the measured strain on the rocker arm and the first relation coefficient; calculating a second relation coefficient between the rocker elephant foot stress and the contact stress of the rocker roller and the camshaft through simulation or experimental test; and calculating the actual contact stress of the rocker roller and the camshaft according to the actual stress of the rocker elephant foot and the second relation coefficient. The contact stress between the camshaft and the rocker roller is indirectly tested by testing the strain of the rocker, so that the test cost can be reduced, and the test accuracy can be improved.
Drawings
In order to more clearly illustrate the technical solutions in the present application or the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
FIG. 1 is a schematic illustration of an engine valve train according to an embodiment of the present application;
fig. 2 is a schematic flow chart of a camshaft contact stress testing method according to an embodiment of the present disclosure.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying figures are described in detail below.
In the following description, specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of implementation in many different ways than those herein set forth and of similar import to those skilled in the art without departing from the spirit and scope of this application. The present application is therefore not limited to the specific embodiments disclosed below.
Referring to fig. 1 and 2, fig. 1 is a schematic structural diagram of a valve train of an engine according to an embodiment of the present disclosure; fig. 2 is a schematic flow chart of a camshaft contact stress testing method according to an embodiment of the present disclosure.
A specific embodiment of the present application provides a camshaft contact stress test method, where a camshaft 1 is a component of an engine valve train, as shown in fig. 1, a middle portion of a rocker arm 2 is rotatably connected to a rocker arm shaft 5, one end of the rocker arm 2 is hinged with a rocker arm roller 3, the rocker arm roller 3 contacts with the camshaft 1 to form a connection pair 6, the other end of the rocker arm 2 is hinged to a rocker arm elephant foot 4, the action of the rocker arm elephant foot 4 is to ensure that an acting force of a valve spring 9 is always vertical upward, a lower end of the rocker arm elephant foot 4 is connected with a valve bridge 8, the valve bridge 8 is connected with a valve stem, the valve spring 8 is sleeved on the valve stem, and the test method includes:
step 1: the strain of test rocking arm 2 specifically can paste foil gage 7 on rocking arm 2, through foil gage 7 test rocking arm 2 strain, for example can be close to the surface paste foil gage 7 of the one end of rocking arm elephant foot 4 on rocking arm 2, have sufficient space on rocking arm 2 and paste foil gage 7, paste foil gage 7 for the tradition on camshaft 1, can effectively reduce foil gage 7's the degree of difficulty of pasting, need not to punch on camshaft 1 moreover, therefore the test structure is comparatively simpler.
Step 2: a first relation coefficient E between the stress of the elephant foot of the rocker arm and the strain of the rocker arm is tested through experiments, wherein E is F/mu, F is the stress of the elephant foot of the rocker arm, and mu is the strain of the rocker arm. Wherein the force acting on the rocker elephant foot 4 can be calculated by experimentally testing the compression amount of the valve spring 9 acting on the rocker elephant foot 4. Wherein the displacement of the valve spring 9 can be tested using an eddy current displacement sensor 10.
And step 3: calculating the actual stress F of the rocker elephant foot 4 according to the measured strain on the rocker arm 2 and the first relation coefficient(actual measurement)，F(actual measurement)＝Eμ(actual measurement)In which μ(actual measurement)Is the strain of the rocker arm tested by the strain gage 7.
And 4, step 4: calculating a second relation coefficient S between the rocker elephant foot stress and the contact stress of the rocker roller 3 and the camshaft 1 through simulation or experimental testcSpecifically, it can be obtained by the following empirical formula:
and 5: calculating the actual contact stress sigma of the rocker roller 3 and the camshaft 1 according to the actual stress of the rocker elephant foot 4 and the second relation coefficient(actual measurement)，σ(actual measurement)＝Sc*F(actual measurement)。
The contact stress between the camshaft 1 and the rocker roller 3 is indirectly tested by testing the strain of the rocker, so that the test cost can be reduced, and the test accuracy can be improved.
Specifically, the compression amount of the valve spring 9 is tested while testing the strain of the rocker arm 2, to check the accuracy of the strain output. Because the contact stress between the camshaft 1 and the rocker roller 3 is mainly caused by the valve spring force and the inertia force thereof, the test rocker 2 can more accurately reflect the contact stress between the camshaft 1 and the rocker roller 3, and the test is more accurate. The test signal transmission signal path is: the strain gauge measures that the rocker arm is strained to the full-bridge circuit and then to the amplifier, and finally to the computer.
In one embodiment of the present application, after calculating the actual contact stress of the rocker roller 3 and the camshaft 1, a contact stress curve of the rocker roller 3 and the camshaft 1 in a preset period is obtained. Because the displacement period of the valve spring 9 is the same as the strain period of the rocker arm 2, the displacement curve of the valve spring 9 is tested by using the eddy current displacement sensor 10, and the displacement curve and the strain curve of the rocker arm can be compared in the same coordinate system to test the accuracy of the test.
In addition, since the contact stress between the camshaft 1 and the rocker roller 3 is mainly caused by the valve spring force and the inertial force thereof, the contact stress between the camshaft 1 and the rocker roller 3 can also be calculated by testing the valve spring pressure and the movement speed of the valve spring.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. A camshaft contact stress testing method is characterized by comprising the following steps:
testing the strain of the rocker arm;
testing a first relation coefficient between the stress of the elephant foot of the rocker arm and the strain of the rocker arm through experiments;
calculating the actual stress of the elephant foot of the rocker arm according to the measured strain on the rocker arm and the first relation coefficient;
calculating a second relation coefficient between the rocker elephant foot stress and the contact stress of the rocker roller and the camshaft through simulation or experimental test;
and calculating the actual contact stress of the rocker roller and the camshaft according to the actual stress of the rocker elephant foot and the second relation coefficient.
2. The camshaft contact stress testing method of claim 1, wherein the step of testing the strain of the rocker arm comprises:
and adhering a strain gauge on the rocker arm, and testing the strain of the rocker arm through the strain gauge.
3. The method for testing contact stress of a camshaft according to claim 2, wherein the strain gauge is attached to a surface of the rocker arm near one end of the rocker arm elephant foot.
4. The camshaft contact stress testing method according to claim 1, wherein the step of experimentally testing the first coefficient of relationship between the rocker elephant foot force and the rocker strain comprises:
and calculating the stress acting on the rocker arm elephant foot by testing the compression amount of a valve spring acting on the rocker arm elephant foot.
5. The camshaft contact stress testing method according to claim 4, wherein the compression amount of the valve spring is tested while the strain of the rocker arm is tested.
6. The camshaft contact stress test method according to any one of claims 1 to 5, wherein after calculating the actual contact stress of the rocker arm roller and the camshaft, a contact stress curve of the rocker arm roller and the camshaft in a preset period is obtained.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210326539.0A CN114689231A (en) | 2022-03-30 | 2022-03-30 | Camshaft contact stress testing method |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202210326539.0A CN114689231A (en) | 2022-03-30 | 2022-03-30 | Camshaft contact stress testing method |
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030029402A1 (en) * | 2001-08-07 | 2003-02-13 | Pomerleau Daniel Guy | Variable valve timing system for an internal combustion engine |
| US20130306013A1 (en) * | 2010-03-19 | 2013-11-21 | Eaton Corporation | Sensing and control of a variable valve actuation system |
| CN104411951A (en) * | 2012-04-30 | 2015-03-11 | 伊顿公司 | Monitoring and diagnosis of variable valve actuation systems |
| CN205876414U (en) * | 2016-06-30 | 2017-01-11 | 皆可博(苏州)车辆控制系统有限公司 | Engine rocking arm is like sufficient structure |
| CN108267253A (en) * | 2018-01-23 | 2018-07-10 | 安徽华菱汽车有限公司 | The test method of contact stress between engine rocker roller and camshaft |
| CN112577649A (en) * | 2020-12-09 | 2021-03-30 | 中国船舶重工集团海装风电股份有限公司 | Wind power gearbox bearing stress testing method |
-
2022
- 2022-03-30 CN CN202210326539.0A patent/CN114689231A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20030029402A1 (en) * | 2001-08-07 | 2003-02-13 | Pomerleau Daniel Guy | Variable valve timing system for an internal combustion engine |
| US20130306013A1 (en) * | 2010-03-19 | 2013-11-21 | Eaton Corporation | Sensing and control of a variable valve actuation system |
| CN104411951A (en) * | 2012-04-30 | 2015-03-11 | 伊顿公司 | Monitoring and diagnosis of variable valve actuation systems |
| CN205876414U (en) * | 2016-06-30 | 2017-01-11 | 皆可博(苏州)车辆控制系统有限公司 | Engine rocking arm is like sufficient structure |
| CN108267253A (en) * | 2018-01-23 | 2018-07-10 | 安徽华菱汽车有限公司 | The test method of contact stress between engine rocker roller and camshaft |
| CN112577649A (en) * | 2020-12-09 | 2021-03-30 | 中国船舶重工集团海装风电股份有限公司 | Wind power gearbox bearing stress testing method |
Non-Patent Citations (3)
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| 丁志强;王奔;刘世锋;张学龙;: "发动机凸轮轴与摇臂滚子接触应力试验研究", 机械工程师, no. 09, 10 September 2020 (2020-09-10) * |
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