CN111373880B - Testing device for fatigue strength of engine connecting rod - Google Patents
Testing device for fatigue strength of engine connecting rod Download PDFInfo
- Publication number
- CN111373880B CN111373880B CN200910124885.5A CN200910124885A CN111373880B CN 111373880 B CN111373880 B CN 111373880B CN 200910124885 A CN200910124885 A CN 200910124885A CN 111373880 B CN111373880 B CN 111373880B
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- connecting rod
- piston pin
- bearing bush
- seat
- hole
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Abstract
The invention belongs to the technical field of engine part tests, and particularly relates to a test device for fatigue strength of an engine connecting rod. The device comprises an electro-hydraulic servo fatigue testing machine, a piston pin device assembly and a connecting rod journal device assembly, wherein the piston pin device assembly comprises a piston pin seat, a connecting rod small-end bushing, a piston pin, a first bearing bush, a piston pin cover and a first bolt; the connecting rod journal device assembly comprises a second bolt, a connecting rod journal cover, a second bearing bush, a connecting rod big end bearing bush, a non-standard crankshaft, an O-shaped rubber sealing ring and a connecting rod journal seat. The invention is a test device for carrying out the fatigue test of the connecting rod on the electro-hydraulic servo fatigue test machine, fully considers the cooling lubrication of a large-head bearing bush and a small-head bushing, has simple and convenient installation and accurate positioning, and can measure the fatigue strength of connecting rods of different types through parametric design.
Description
Technical Field
The invention belongs to the technical field of engine part tests, and particularly relates to a test device for fatigue strength of an engine connecting rod.
Background
The connecting rod is the main stressed moving part in the engine and has enough strength under the compression and reciprocating and rotating inertial stretching effects of gas pressure in the cylinder. However, to reduce the inertial forces experienced by the crankshaft and crankcase, the connecting rods should be as light as possible. Therefore, the evaluation of the fatigue strength of the connecting rod is particularly important in the design and production processes. The connecting rod fatigue test can be carried out on a special engine bench or a general fatigue testing machine. The test is carried out on the bench, the result is accurate and reliable, the method is one of irreplaceable means for engine shaping and reliability verification, but the period is long, the cost is high, and especially, the cost-effectiveness ratio is low for multi-scheme structure screening. When the method is carried out on a part fatigue testing machine, the time is short, the cost is low, and the method is convenient and easy to implement.
When the engine works, the connecting rod big end bearing bush is generally lubricated by pressure, and the small end bushing bush is generally lubricated by splashing. In the part fatigue test, it is difficult to simulate the above lubrication manner. If lubrication and cooling are not carried out, in the test process, overheating and rolling deformation can occur among the pin, the shaft and the bearing bush, the test result is influenced, and even the test cannot be continuously carried out.
Disclosure of Invention
The invention provides a testing device for fatigue strength of an engine connecting rod with cooling and lubricating capabilities to overcome the defects of the prior art.
The technical scheme of the invention is as follows: the test device for the fatigue strength of the engine connecting rod comprises an electro-hydraulic servo fatigue test machine, and further comprises a piston pin device assembly and a connecting rod journal device assembly, wherein the piston pin device assembly comprises a piston pin boss, a connecting rod small-end bush, a piston pin, a first bearing bush, piston pin covers and first bolts, the piston pin boss is connected with an oil cylinder in the electro-hydraulic servo fatigue test machine, the two piston pin covers are respectively connected with the piston pin boss through 4 first bolts, the first bearing bushes are respectively arranged between the piston pin and the piston pin boss and between the piston pin and the piston pin covers in bilateral symmetry, a bush hole of the first bearing bush is in interference connection with the piston pin, and the two piston pin covers are connected with the piston pin at symmetrical positions on the left side and the right side of the piston pin; grooves are formed in the piston pin seat and the piston pin cover, the grooves in the piston pin seat and the piston pin cover are positioning grooves of the first bearing bush, and a convex shoulder of the first bearing bush is arranged in the grooves; a first hole and a second hole are formed in the piston pin boss right above the tested connecting rod, the piston pin boss is connected with a cooling oil pump through the first hole, cooling oil enters the connecting rod small-end oil hole through a cooling oil path between the first hole and the second hole in the piston pin boss, an oil film is formed between the connecting rod small-end bushing and the piston pin, and the connecting rod small-end bushing is arranged in the connecting rod small-end hole in an interference fit mode and is in clearance connection with the piston pin; the connecting rod journal device assembly comprises a second bolt, a connecting rod journal cover, a second bearing bush, a connecting rod big end bearing bush, a non-standard crankshaft, an O-shaped rubber sealing ring and a connecting rod journal seat, wherein the connecting rod journal cover and the connecting rod journal seat are connected by 8M 16 second bolts; a second bearing bush is respectively arranged between the connecting rod journal cover and the non-standard crankshaft and between the connecting rod journal seat and the non-standard crankshaft in a bilateral symmetry manner, and the second bearing bushes are in interference connection with the non-standard crankshaft; an O-shaped rubber sealing ring is arranged in an upper ring groove of the non-standard crankshaft; the connecting rod journal seat is connected with a force sensor in the electro-hydraulic servo fatigue testing machine; a steel pipe is welded at the hole on the connecting rod journal cover; the big end bearing bush of the connecting rod is arranged in the big end hole of the connecting rod in an interference way and is connected with the non-standard crankshaft in an interference way.
The invention has the beneficial effects that: the invention is a test device for carrying out the fatigue test of the connecting rod on the electro-hydraulic servo fatigue test machine, fully considers the cooling lubrication of a large-head bearing bush and a small-head bushing, has simple and convenient installation and accurate positioning, and can measure the fatigue strength of connecting rods of different types through parametric design.
Drawings
The invention has 6 figures, wherein, figure 1 is the best embodiment of the invention and can also be the figure of the abstract of the specification.
FIG. 1 is a schematic structural diagram of a testing device for fatigue strength of an engine connecting rod;
FIG. 2 is a schematic view of the piston pin boss and piston pin cover assembly of FIG. 1;
FIG. 3 is a schematic view of the first bearing insert of FIG. 1;
FIG. 4 is a side view of the piston pin boss structure of FIG. 1;
FIG. 5 is a side view of the connecting rod journal cover structure of FIG. 1;
fig. 6 is a side view of the connecting rod journal seat structure of fig. 1.
Detailed Description
The preferred embodiments of the present invention will be further described with reference to the accompanying drawings.
As shown in figure 1, the testing device for the fatigue strength of the engine connecting rod comprises an electro-hydraulic servo fatigue testing machine, and further comprises a piston pin device assembly and a connecting rod journal device assembly, wherein the piston pin device assembly comprises a piston pin seat 1, a connecting rod small-head bushing 2, a piston pin 3, a first bearing bush 4, a piston pin cover 5 and a first bolt 6, the piston pin seat 1 is connected with an oil cylinder in the electro-hydraulic servo fatigue testing machine, and the two piston pin covers 5 are respectively connected with the piston pin seat 1 through 4 first bolts 6, so that the piston pin seat 1 and the piston pin cover 5 are prevented from being worn and deformed in the testing process. A first bearing bush 4 is respectively arranged between the piston pin 3 and the piston pin boss 1 and between the piston pin 3 and the piston pin cover 5 in bilateral symmetry, a bearing hole of the first bearing bush 4 is in interference connection with the piston pin 3, and the two piston pin covers 5 are connected with the piston pin 3 at symmetrical positions on the left side and the right side of the piston pin 3; the tensile and compression load generated by the oil cylinder is transmitted to the tested connecting rod through the piston pin base 1 and the piston pin cover 5 through the piston pin 3.
As shown in fig. 2, the piston pin boss 1 and the piston pin cover 5 are both provided with a groove 14, the groove 14 on the piston pin boss 1 and the piston pin cover 5 is a positioning groove of the first bearing bush 4, and is a circumferential groove which is formed by combining and processing the piston pin boss 1 and the piston pin cover 5 after the first bolt 4 is fastened.
As shown in fig. 3, the shoulder 15 of the first bearing shell 4 is seated in the recess 14 to prevent axial play of the first bearing shell 4 during testing. As shown in FIG. 4, in order to prevent the small-end bush 2 from being overheated and rolled and deformed, a first hole 16 and a second hole 17 are arranged right above a tested connecting rod on the piston pin boss 1, the piston pin boss 1 is connected with a cooling oil pump through the first hole 16, cooling oil enters the small-end oil hole of the connecting rod through a cooling oil path between the first hole 16 and the second hole 17 on the piston pin boss 1, the small-end bush 2 of the connecting rod is arranged in the small-end hole of the connecting rod in an interference mode and is in clearance connection with the piston pin 3, an oil film is formed between the small-end bush 2 of the connecting rod and the piston pin 3, the small-end bush 2 of the connecting rod and the piston pin 3 are isolated, overheating caused by contact and separation of the small-end bush 2 and the small-end bush 3 of the connecting rod due to tension and compression loads in the test process can be avoided, and meanwhile, continuously. In the test, the cooling oil pump was kept in an open state.
As shown in fig. 1, the connecting rod journal device assembly comprises a second bolt 7, a connecting rod journal cover 8, a second bearing bush 9, a connecting rod big end bearing bush 10, a non-standard crankshaft 11, an O-shaped rubber sealing ring 12 and a connecting rod journal seat 13, wherein the connecting rod journal cover 8 and the connecting rod journal seat 13 are connected by 8M 16 second bolts 7; in order to prevent the abrasion and deformation of the connecting rod journal cover 8 and the connecting rod journal seat 13 in the test process. A second bearing bush 9 is respectively arranged between the connecting rod journal cover 8 and the non-standard crankshaft 11 and between the connecting rod journal seat 13 and the non-standard crankshaft 11 in a bilateral symmetry way, and the bearing bush holes of the second bearing bush 9 are in interference connection with the non-standard crankshaft 11; the engine oil which cools the small end bush 2 of the connecting rod and the piston pin 3 flows to an oil pool which is composed of a connecting rod journal cover 8 and a connecting rod journal seat 13 along the tested connecting rod body; an O-shaped rubber sealing ring 12 is arranged in an upper ring groove of the non-standard crankshaft 11 to prevent engine oil in an oil pool from leaking between the connecting rod journal cover 8, the connecting rod journal seat 13 and the non-standard crankshaft 11; the connecting rod journal seat 13 is connected with a force sensor in the electro-hydraulic servo fatigue testing machine.
As shown in figure 5, a steel pipe 19 is welded at the hole 18 on the connecting rod journal cover 8, when the liquid level in the oil pool is higher than the lower edge of the hole 18, the redundant cooling oil flows back to the oil tank through the steel pipe 19, and the liquid level in the oil pool is ensured to be constant. As shown in fig. 1, the connecting rod big-end bearing bush 10 is arranged in the connecting rod big-end hole in an interference manner and is in interference connection with the non-standard crankshaft 11, the connecting rod big-end bearing bush 10 is always soaked in cooling machine oil and is in a lubrication cooling state for a long time, and the big-end bearing bush 10 is prevented from being overheated, rolled and deformed in a test.
As shown in fig. 6, the screw hole 20 of the connecting rod journal seat 13 is connected with a switch valve, so that the redundant cooling machine oil in the oil pool can be discharged when the connecting rod journal seat is assembled and disassembled. A force sensor in the electro-hydraulic servo fatigue testing machine monitors the load acting on a tested connecting rod through a connecting rod journal cover 8, a non-standard crankshaft 11 and a connecting rod journal seat 13, and feeds load information back to a controller in the electro-hydraulic servo fatigue testing machine to form closed-loop control.
During testing, the oil cylinder in the electro-hydraulic servo fatigue testing machine applies sine wave type tension and compression loads to the tested connecting rod, test loads with different sizes, fracture and pass through 1 × 107Results of two tests in a second cycle, the load of the tested connecting rod breaking and the passing of 1 × 107The average value of the loads of the secondary cycle is the fatigue strength of the tested connecting rod.
Claims (1)
1. Engine connecting rod fatigue strength's test device, including the servo fatigue testing machine of electricity liquid, its characterized in that: the piston pin device assembly comprises a piston pin seat (1), a connecting rod small-end bushing (2), a piston pin (3), first bearing bushes (4), piston pin covers (5) and first bolts (6), the piston pin seat (1) is connected with an oil cylinder in an electro-hydraulic servo fatigue testing machine, the two piston pin covers (5) are respectively connected with the piston pin seat (1) through the 4 first bolts (6), one first bearing bush (4) is respectively arranged in bilateral symmetry between the piston pin (3) and the piston pin seat (1) and between the piston pin (3) and the piston pin covers (5), a bush hole of the first bearing bush (4) is in interference connection with the piston pin (3), and the two piston pin covers (5) are connected with the piston pin (3) at symmetrical positions on the left side and the right side of the piston pin (3); grooves (14) are formed in the piston pin seat (1) and the piston pin cover (5), the grooves (14) in the piston pin seat (1) and the piston pin cover (5) are positioning grooves of the first bearing bush (4), and a convex shoulder (15) of the first bearing bush (4) is arranged in the groove (14); a first hole (16) and a second hole (17) are formed in the piston pin boss (1) right above a tested connecting rod, the piston pin boss (1) is connected with a cooling oil pump through the first hole (16), cooling oil enters a small end oil hole of the connecting rod through a cooling oil path between the first hole (16) and the second hole (17) in the piston pin boss (1), an oil film is formed between a small end bushing (2) of the connecting rod and a piston pin (3), and the small end bushing (2) of the connecting rod is arranged in the small end hole of the connecting rod in an interference fit mode and is in clearance connection with the piston pin (3);
the connecting rod journal device assembly comprises a second bolt (7), a connecting rod journal cover (8), a second bearing bush (9), a connecting rod big end bearing bush (10), a non-standard crankshaft (11), an O-shaped rubber sealing ring (12) and a connecting rod journal seat (13), wherein the connecting rod journal cover (8) and the connecting rod journal seat (13) are connected through 8M 16 second bolts (7); a second bearing bush (9) is respectively arranged between the connecting rod journal cover (8) and the non-standard crankshaft (11) and between the connecting rod journal seat (13) and the non-standard crankshaft (11) in a bilateral symmetry manner, and the second bearing bushes (9) are in interference connection with the non-standard crankshaft (11); an O-shaped rubber sealing ring (12) is arranged in an upper ring groove of the non-standard crankshaft (11); the connecting rod journal seat (13) is connected with a force sensor in the electro-hydraulic servo fatigue testing machine; a steel pipe (19) is welded at a hole (18) on the connecting rod journal cover (8); the connecting rod big end bearing bush (10) is arranged in the connecting rod big end hole in an interference mode and is connected with the non-standard crankshaft (11) in an interference mode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910124885.5A CN111373880B (en) | 2009-12-25 | 2009-12-25 | Testing device for fatigue strength of engine connecting rod |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN200910124885.5A CN111373880B (en) | 2009-12-25 | 2009-12-25 | Testing device for fatigue strength of engine connecting rod |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111373880B true CN111373880B (en) | 2013-11-13 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN200910124885.5A Expired - Fee Related CN111373880B (en) | 2009-12-25 | 2009-12-25 | Testing device for fatigue strength of engine connecting rod |
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| CN (1) | CN111373880B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108776016A (en) * | 2018-09-13 | 2018-11-09 | 河南柴油机重工有限责任公司 | A kind of connecting rod fatigue experimental device that reliability is high |
| CN112666016A (en) * | 2020-12-21 | 2021-04-16 | 中国北方发动机研究所(天津) | Tensile-compressive fatigue test device for engine cylinder block component |
| CN113790950A (en) * | 2021-09-17 | 2021-12-14 | 长春市镨策试验仪器有限责任公司 | Pressure-bearing device for simulating high-energy-storage rock mass excavation unloading test and sealing method |
-
2009
- 2009-12-25 CN CN200910124885.5A patent/CN111373880B/en not_active Expired - Fee Related
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108776016A (en) * | 2018-09-13 | 2018-11-09 | 河南柴油机重工有限责任公司 | A kind of connecting rod fatigue experimental device that reliability is high |
| CN108776016B (en) * | 2018-09-13 | 2023-12-19 | 河南柴油机重工有限责任公司 | Connecting rod fatigue test device with high reliability |
| CN112666016A (en) * | 2020-12-21 | 2021-04-16 | 中国北方发动机研究所(天津) | Tensile-compressive fatigue test device for engine cylinder block component |
| CN113790950A (en) * | 2021-09-17 | 2021-12-14 | 长春市镨策试验仪器有限责任公司 | Pressure-bearing device for simulating high-energy-storage rock mass excavation unloading test and sealing method |
| CN113790950B (en) * | 2021-09-17 | 2022-05-17 | 长春市镨策试验仪器有限责任公司 | Pressure-bearing device for simulating high-energy-storage rock mass excavation unloading test and sealing method |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| GR03 | Grant of secret patent right | ||
| GRSP | Grant of secret patent right | ||
| DC01 | Secret patent status has been lifted | ||
| DC01 | Secret patent status has been lifted | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131113 Termination date: 20211225 |