CN113237741A - Hydraulic clamp for electro-hydraulic servo fatigue testing machine - Google Patents
Hydraulic clamp for electro-hydraulic servo fatigue testing machine Download PDFInfo
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- CN113237741A CN113237741A CN202110549864.9A CN202110549864A CN113237741A CN 113237741 A CN113237741 A CN 113237741A CN 202110549864 A CN202110549864 A CN 202110549864A CN 113237741 A CN113237741 A CN 113237741A
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- G—PHYSICS
- 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
- G01N3/02—Details
- G01N3/04—Chucks
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- G—PHYSICS
- 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
- G01N3/32—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces
- G01N3/36—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces generated by pneumatic or hydraulic means
Abstract
The invention discloses a hydraulic clamp for an electro-hydraulic servo fatigue testing machine, and belongs to the technical field of electro-hydraulic servo fatigue testing machines. This hydraulically operated fixture includes the same last anchor clamps and lower anchor clamps of structure, goes up anchor clamps and all includes locking screw thread, anchor clamps overcoat and cyclic annular clamp splice down, wherein: the clamp outer sleeve is formed by hermetically connecting a clamp head shell and an end cover, the clamp head shell and the end cover are both provided with a step-shaped annular cavity, the annular clamping block is placed in the annular cavity of the clamp head shell and used for clamping a test sample, and a piston is accommodated in the annular cavity of the end cover; the annular clamping block is connected with the piston through a circular base plate; the piston can reciprocate along the axis of the annular clamping block under the action of hydraulic pressure, so that the annular clamping block is driven to clamp a test sample or release the test sample. The fixture reduces the fracture probability of the sample clamping end in the fatigue test process and improves the fatigue test efficiency.
Description
Technical Field
The invention relates to the technical field of electro-hydraulic servo fatigue testing machines, in particular to a hydraulic clamp for an electro-hydraulic servo fatigue testing machine.
Background
Fatigue failure is one of the primary modes of failure of structural materials during practical engineering applications, and component failure due to fatigue is statistically about 80% of all component failure. And the fatigue fracture is often characterized by sudden and catastrophic characteristics, and the loss caused by the fatigue fracture is generally huge. Therefore, the fatigue problem of the material is an inevitable main link before the practical application of the component, and the fatigue performance of the material must be accurately, safely and quickly measured to ensure the service safety of the component.
The fatigue test is a test with high specialty and has high requirements on test equipment, samples and personnel. The requirement of the fatigue test on the surface roughness Ra of the parallel section of the test piece is less than or equal to 0.2um, the high requirement causes the processing cost of each test piece to be hundreds of yuan, and a set of fatigue test requires about 30 fatigue test pieces. A sample needs to continuously work for several hours to dozens of hours, a group of fatigue tests need to continuously work for about 1 month around day and night, the fatigue tests are charged according to the test time, even if the charging standard of the conventional test is 100-200/hour, under the condition of meeting the test parameter requirements, the shorter the test period is, the lower the test cost is, and the more the material is beneficial to popularization and application. If a grip end break occurs during the test, the test results obtained for this specimen will be invalid. The time consumption and the sample damage caused by the test can not be changed, so that the sample is deformed during installation or the clamping end is broken in the test process, the test time is greatly wasted, the test cost is increased, and the development difficulty of materials is increased.
The electro-hydraulic servo fatigue testing machine using the hydraulic oil source is the most widely used equipment in fatigue tests, can be used for various tests such as stretching, compression, bending, high cycle fatigue, low cycle fatigue, fracture toughness, crack propagation rate and the like, a hydraulic clamp used by the electro-hydraulic servo fatigue testing machine at the present stage is provided with a wedge-shaped clamping block, and the working principle of the wedge-shaped clamping block is that the hydraulic clamp provides enough pressure for the wedge-shaped clamping block to enable grains on the wedge-shaped clamping block to be embedded into the surface of a sample so that the sample does not slip in the working process. However, the surface of the sample can generate clamp marks during clamping, and cracks can be initiated and broken from the clamp marks during the test, so that the test result is invalid. In addition, the sample is subjected to the resultant force of the axial direction and the horizontal direction when the sample is clamped by the wedge-shaped clamping block, and the resultant force can cause the sample to deform in the clamping process for some samples, so that the sample is scrapped. In the prior art, various measures are adopted by a tester manufacturer to solve the problem caused by clamping of the wedge-shaped clamping block, and the test machine manufacturer adopts a method for setting a sample protection program to avoid scrapping of the sample by unloading excessive load borne by the sample in the clamping process; some testing machines protect the sample by changing the control mode in the sample clamping process to unload the excessive load born by the sample. None of these fundamentally addresses the problem of specimen deformation during specimen clamping. The best method for solving the problem is to adopt a horizontal pushing hydraulic clamp, and the horizontal pushing hydraulic clamp can ensure that the sample is only subjected to horizontal force and not subjected to axial force in the clamping process, so that the sample is prevented from deforming in the clamping process. However, the flat push hydraulic clamp is bulky and costly due to its structure. On one hand, conventional fatigue testing machines do not have sufficient space to install a flat push hydraulic clamp; on the other hand, the cost of the testing machine is greatly increased by using the flat-pushing clamp, so that the cost of a fatigue test is increased, and the difficulty of material research and development and application is increased. In addition, the traditional high-temperature test uses a mechanical clamp, the mechanical clamp generates a gap between the mechanical clamp and a sample due to expansion with heat and contraction with cold in the heating process, the mechanical clamp needs to be manually and repeatedly locked to prevent the test from failing, but a great deal of operation inconvenience is brought to the human at a high temperature, and the fatigue test efficiency is influenced. The requirement of the fatigue test on the coaxiality of the testing machine is high, the coaxiality of the electro-hydraulic servo fatigue testing machine is required to be less than or equal to 5%, and the use of the hydraulic wedge-shaped clamp can increase the lateral force borne by the test sample during the test, so that the coaxiality of the whole fatigue machine testing system is increased, and the risk of test failure is increased.
Disclosure of Invention
Aiming at the problems that the surface of a sample is damaged due to the fact that sawteeth on a wedge-shaped clamping block used by a traditional hydraulic clamp are sunk into the sample when the wedge-shaped clamping block is used for clamping, or a test result is invalid due to the fact that a clamping end is broken; the invention aims to provide a hydraulic clamp for an electro-hydraulic servo fatigue testing machine, which reduces the fracture probability of a clamping end of a sample in the fatigue testing process and improves the fatigue testing efficiency.
In order to achieve the purpose, the technical scheme adopted by the invention is as follows:
the utility model provides a hydraulic fixture for servo fatigue test machine of electricity liquid, includes the same last anchor clamps and lower anchor clamps of structure, goes up anchor clamps and all includes locking screw thread, anchor clamps overcoat and cyclic annular clamp splice with lower anchor clamps, wherein: the clamp outer sleeve is formed by hermetically connecting a clamp head shell and an end cover, the clamp head shell and the end cover are both provided with a step-shaped annular cavity, the annular clamping block is placed in the annular cavity of the clamp head shell and used for clamping a test sample, and a piston is accommodated in the annular cavity of the end cover; the annular clamping block is connected with the piston through a circular base plate; the piston can reciprocate along the axis of the annular clamping block under the action of hydraulic pressure, so that the annular clamping block is driven to clamp a test sample or release the test sample.
The locking thread is used for connecting the hydraulic clamp piston with the fatigue testing machine.
The piston is of a stepped structure, and the front end and the rear end of the piston are respectively in close contact with the inner wall of the annular cavity of the end cover; a first hydraulic cavity is formed between the front end of the piston and the stepped surface of the annular cavity of the end cover; meanwhile, a second hydraulic cavity is formed between the front end of the piston and the rear end face of the chuck shell; the first hydraulic cavity and the second hydraulic cavity are respectively connected with a pressure oil source through pipelines.
The piston is welded or connected with the round chassis through a bolt; the circular base plate is connected with the annular clamping blocks through bolts, annular protrusions are arranged on the circular base plate and clamped at the rear end threads of the annular clamping blocks, so that the stability of connection of the circular base plate and the annular clamping blocks is enhanced, and the consistency of axes is kept.
The contact surfaces of the annular cavity of the chuck shell and the annular clamping block are respectively provided with an internal thread and an external thread, and the annular clamping block is fixed in the clamp outer sleeve through the matching of the internal thread and the external thread.
The tooth form of the external thread on the annular clamping block is triangular, the angle alpha between the surface of the triangular tooth form close to the processing end and the axis of the annular clamping block is 15-30 degrees, and the angle beta between the surface of the triangular tooth form far away from the processing end and the axis of the annular clamping block is 60-75 degrees; the angle between the upper surface of the triangular tooth shape of the upper clamp and the axis of the annular clamping block is 60-75 degrees, and the angle between the lower surface of the triangular tooth shape and the axis of the annular clamping block is 15-30 degrees; the external diameter and pitch of the internal thread of the annular cavity of the chuck shell are matched with the internal diameter and pitch of the external thread.
The annular clamping block consists of three equally-divided petal-shaped clamping blocks, the included angle of each petal-shaped clamping block is 110 degrees, and the remaining 30-degree space is used for clamping a sample.
The material of cyclic annular clamp splice is the super high strength steel of hardness 60 ~ 65HRC, and cyclic annular clamp splice is direct and sample contact, and the contact surface of cyclic annular clamp splice and sample is that the plain noodles does not have the sawtooth line, can guarantee not harm the sample surface when centre gripping sample.
When the hydraulic clamp works, liquid is fed into the first hydraulic cavity and pressurized, and the piston is driven to move towards the clamping end, so that the annular clamping blocks are pushed to approach towards the axial direction, and a sample is clamped; and the liquid is fed into the second hydraulic cavity and pressurized, and the piston is driven to move towards the position far away from the clamping end, so that the sample is released.
And the clamp jacket is provided with a cooling water inlet and a cooling water outlet which are connected with a cooling pipeline in the clamp jacket and used for circulating cooling water.
The upper end of the locking thread of the upper clamp is sleeved with a locking ring and a gasket and then is connected with an axial force sensor, and the axial force sensor is connected with a fatigue testing machine; the lower end of the locking thread of the lower clamp is sleeved with the locking ring and the gasket and then is connected with the piston rod.
The design mechanism of the hydraulic clamp is as follows:
1. provided is a hydraulic clamp structure. The hydraulic clamp mainly comprises three parts, namely a locking thread, a clamp outer sleeve and an annular clamping block. The locking thread is used for connecting the hydraulic clamp with the main shaft of the acting cylinder of the testing machine, so that the connection rigidity of the hydraulic clamp and the testing machine is guaranteed, and looseness cannot occur in the testing process. The clamp outer sleeve is connected with a hydraulic source through an oil pipe, the hydraulic source provides power for the hydraulic clamp to clamp the sample, the oblique downward internal thread is processed on the contact surface of the clamp outer sleeve and the annular clamping block and is matched with the external thread of the annular clamping block, and the hydraulic cylinder clamps the sample through the annular clamping block which extrudes the external thread of the annular clamping block during working. Every cyclic annular clamp splice comprises three partition petal form clamp splice, and every part accounts for 110, and remaining 30 spaces are used for pressing from both sides tight sample, and cyclic annular clamp splice adopts the super high strength steel that hardness is 60 ~ 65HRC to make and forms, and cyclic annular clamp splice is direct and sample contact, and cyclic annular clamp splice is the plain noodles with the contact surface of sample and does not have the sawtooth line, can guarantee not harm the sample surface when centre gripping sample.
2. High-temperature test function of the hydraulic clamp. Traditional high temperature fatigue test can only use mechanical fixture, and mechanical fixture needs the manual work to remove the locking sample when using, but because the expend with heat and contract with cold of sample and mechanical fixture is different at high temperature fatigue test's in-process, can produce the clearance between sample and the mechanical fixture and make the sample take place to become flexible thereby lead to the experiment failure, unless manual locking once more in high temperature test process, but mechanical fixture's the very high manual locking of removing of temperature is more difficult in high temperature test. Processing has the cooling water passageway to make this anchor clamps have the water-cooling function in the novel hydraulic fixture overcoat, can take away the heat that sample or high temperature furnace produced radiation, avoid because of the damage that brings for hydraulic fixture that the high temperature leads to, consequently this anchor clamps can be used to in the high temperature test, and this anchor clamps are hydraulic fixture, hydraulic fixture also can the self-holding sample after expend with heat and contract with cold produces the clearance, make the sample be in clamping state all the time, the artifical frequent tight sample of clamp has been avoided also to guarantee experimental stability and accuracy.
3. The coaxiality of the hydraulic clamp is good. The requirement of the fatigue test on the coaxiality of the clamp is very high, the system coaxiality of the tester is required to be not more than 5% in the ASTM standard, the coaxiality of the clamp accounts for a large proportion in the whole tester system, and the accuracy of the fatigue test can be directly influenced by the coaxiality of the clamp. The clamp has the advantages that due to the symmetrical three-petal-shaped clamping block design, the stress of the sample can be more uniform when the sample is clamped, and the clamp can have better coaxiality compared with a transmission hydraulic clamp using two wedge-shaped clamping blocks. Therefore, the clamp has a positive effect on reducing the coaxiality of the testing machine system, and can better promote the accuracy of the fatigue test result.
The invention has the following advantages and beneficial effects:
(1) after the hydraulic clamp is used, the problem that the clamping end of a sample is broken in the fatigue process due to clamping damage in the fatigue process of certain materials is effectively solved, the probability that the clamping end of the sample is broken in the fatigue test process is greatly reduced, and the fatigue test efficiency is improved.
(2) The use and maintenance cost of the whole set of equipment is the same as that of the traditional hydraulic clamp, and the test cost cannot be additionally increased.
(3) The use of this anchor clamps has the promotion effect to the coaxial of testing machine system, can satisfy fatigue test's requirement completely, proves through practice: after the hydraulic clamp is used, the coaxiality of a testing machine system can be improved from 4% to 2%, and the accuracy of a fatigue test result is ensured.
(4) The hydraulic clamp is internally provided with the cooling water channel to have a cooling function, can use some high-temperature tests, can effectively compensate the experimental failure condition caused by the clearance generated by expansion with heat and contraction with cold in the high-temperature fatigue test of the mechanical clamp, and can effectively improve the test efficiency.
Drawings
Fig. 1 is a schematic view of the overall structure of the hydraulic clamp of the present invention.
Fig. 2 is a schematic view of a lower clamp structure of the hydraulic clamp of the present invention.
Fig. 3 is a schematic structural view of an annular clamping block of the hydraulic clamp of the invention.
FIG. 4 is a top view of the annular clamp blocks of the hydraulic clamp of the present invention.
In the figure: 1-lower clamp; 101-locking screw thread; 102-an annular clamp block; 103-a cartridge housing; 104-an end cap; 105-a piston; 106-circular base plate; 107-a first hydraulic chamber; 108-a second hydraulic chamber; 109-line; 110-petal clamp blocks; 2, mounting a clamp; 3-locking ring; 4-a gasket; 5-a piston rod; 6-axial force sensor; 7-water inlet/outlet.
Detailed Description
For a further understanding of the present invention, the following description is given in conjunction with the examples which are set forth to illustrate, but are not to be construed to limit the present invention, features and advantages.
In order to solve the problem of inconvenience in manual operation caused by the fact that a mechanical clamp used in a traditional high-temperature test needs to be manually and repeatedly locked and reduce test cost of material research and development, the invention designs a set of high-temperature test clampElectrohydraulic servoHydraulic clamp for fatigue testing machine.
As shown in fig. 1 to 4, the hydraulic clamp includes an upper clamp 2 and a lower clamp 1 which have the same structure, and each of the upper clamp and the lower clamp includes a locking thread 101, a clamp outer sleeve, and an annular clamp block 102, wherein: the clamp outer sleeve is formed by hermetically connecting a clamp head outer shell 103 and an end cover 104, the clamp head outer shell and the end cover are both provided with a step-shaped annular cavity, the annular clamping block 102 is placed in the annular cavity of the clamp head outer shell 103 and used for clamping a test sample, and a piston 105 is accommodated in the annular cavity of the end cover 104; the annular clamping block 102 is connected with the piston 105 through a circular base plate 106; the piston can reciprocate along the axis of the annular clamping block under the action of hydraulic pressure, so that the annular clamping block is driven to clamp a test sample or release the test sample.
The piston 105 of the hydraulic clamp is of a step-shaped structure, the diameter of the front end (clamping end) of the piston is larger than that of the rear end, the diameter of the front end is 1.5-2 times of that of the rear end, the front end and the rear end of the piston are respectively in close contact with the inner wall of the annular cavity of the end cover, and a sealing ring is arranged on the contact surface; a first hydraulic cavity 107 is formed between the front end of the piston and the stepped surface of the annular cavity of the end cover; meanwhile, a second hydraulic cavity 108 is formed between the front end of the piston and the rear end face of the chuck shell; the first hydraulic chamber and the second hydraulic chamber are respectively connected with a pressure oil source through a pipeline 109.
The piston is welded or connected with the round chassis through a bolt; the circular base plate is connected with the annular clamping blocks through bolts, annular protrusions are arranged on the circular base plate and clamped at the rear end threads of the annular clamping blocks, so that the stability of connection of the circular base plate and the annular clamping blocks is enhanced, and the consistency of axes is kept.
The contact surfaces of the annular cavity of the chuck shell and the annular clamping block are respectively provided with an internal thread and an external thread, and the annular clamping block is fixed in the clamp outer sleeve through the matching of the internal thread and the external thread.
As shown in fig. 3, the thread form of the external thread on the annular clamping block is triangular, the angle between the surface of the triangular thread form close to the processing end and the axis of the annular clamping block is 15-30 degrees, and the angle between the surface of the triangular thread form far away from the processing end and the axis of the annular clamping block is 60-75 degrees; the angle between the upper surface of the triangular tooth shape of the upper clamp and the axis of the annular clamping block is 60-75 degrees, and the angle between the lower surface of the triangular tooth shape and the axis of the annular clamping block is 15-30 degrees; the external diameter and pitch of the internal thread of the annular cavity of the chuck shell are matched with the internal diameter and pitch of the external thread.
As shown in fig. 4, the annular clamping block is composed of three equally-divided petal-shaped clamping blocks 110, the included angle of each petal-shaped clamping block is 110 °, and the space of 30 ° is used for clamping a sample. The material of cyclic annular clamp splice is the super high strength steel of hardness 60 ~ 65HRC, and cyclic annular clamp splice is direct and sample contact, and the contact surface of cyclic annular clamp splice and sample is that the plain noodles does not have the sawtooth line, can guarantee not harm the sample surface when centre gripping sample.
When the hydraulic clamp works, liquid is fed into the first hydraulic cavity and pressurized, and the piston is driven to move towards the clamping end, so that the annular clamping block is pushed to approach towards the axial direction (the external thread of the annular clamping block is squeezed), and a sample is clamped; and the liquid is fed into the second hydraulic cavity and pressurized, and the piston is driven to move towards the position far away from the clamping end, so that the sample is released.
The clamp jacket is provided with a cooling water inlet and a cooling water outlet (such as a water inlet/outlet 7 in fig. 1), and the cooling water inlet and the cooling water outlet are connected with a cooling pipeline in the clamp jacket and used for circulating cooling water.
Locking screw thread 101 is used for the connection of hydraulic fixture's piston and fatigue testing machine last piston rod specifically is: the upper end of the locking thread of the upper clamp is sleeved with the locking ring 3 and the gasket 4 and then is connected with the axial force sensor 6, and the axial force sensor is connected with the fatigue testing machine; the lower end of the locking thread of the lower clamp is sleeved with a locking ring 3 and a gasket 4 and then is connected with a piston rod 5.
The hydraulic clamp disclosed by the invention is used as follows:
(1) and selecting and processing the hydraulic clamp according to the design requirement, and then installing the hydraulic clamp on a fatigue testing machine.
(2) And the fatigue testing machine provided with the novel hydraulic clamp is coaxially verified, so that the coaxiality of a fatigue testing machine system is ensured to meet the test standard.
(3) And selecting a proper clamping block according to the size of the clamping end of the sample, wherein the clamping end of the sample at least extends into 2/3 parts of the hydraulic clamping block, installing the sample, and adjusting the clamping force pressure to a proper value to clamp the sample. And the test sample is ensured not to slip in the fatigue test process.
(4) And setting fatigue test parameters as required and starting a fatigue test.
(5) If the high-temperature test is carried out, the hydraulic clamp needs to be firstly filled with cooling water, then the temperature of the high-temperature furnace is raised, after the temperature reaches the temperature, the temperature is kept for 30min, fatigue test parameters are set, and the fatigue test is started.
The hydraulic clamp disclosed by the invention has the advantages that the brand-new structural design is adopted to avoid the surface damage of the sample caused when the wedge-shaped clamping block is used for clamping the sample in the traditional hydraulic clamp, and the sample deformation risk caused when the wedge-shaped clamping block is used for clamping the sample can be greatly reduced. In addition, cooling water channels are distributed in the hydraulic clamp, cooling water can be used for cooling the hydraulic clamp to avoid damage, the hydraulic clamp can be used in a high-temperature fatigue test, the stability of the clamping force of the sample can be kept constantly due to hydraulic clamping, the problem that the mechanical clamp needs manual repeated locking in the high-temperature fatigue test process can be effectively solved, and the stability and accuracy of the high-temperature fatigue test are also guaranteed. The coaxiality of the device is better than that of a traditional hydraulic clamp, and the coaxiality of an electro-hydraulic servo fatigue test using the device is greatly improved, so that the accuracy of a fatigue test result can be promoted. The device has simple structure and volume similar to that of a wedge-shaped clamp, and the structure of the testing machine is not changed and the cost of the testing machine is not additionally increased by using the clamp.
The hydraulic clamp disclosed by the invention has the following cautions in use:
1. the whole hydraulic clamp is required to be machined by selecting materials and machining according to the drawing requirements, and the machining precision meets the design requirements.
2. During the installation of the sample, it is necessary to ensure that the sample holding end extends into the annular clamping block at least 2/3.
3. During high-temperature test, a cooling water channel must be opened first, and the flow of cooling water reaches 2L/min at 20 ℃.
The hydraulic clamp is suitable for clamping rod-shaped or cylindrical samples, and can not clamp plate-shaped samples. The annular clamping blocks used by the clamp only can clamp the rod-shaped samples with fixed sizes, and the rod-shaped samples with different sizes need to be provided with different annular clamping blocks.
Claims (10)
1. The utility model provides a hydraulic fixture for servo fatigue test machine of electricity liquid which characterized in that: this hydraulically operated fixture includes the same last anchor clamps and lower anchor clamps of structure, goes up anchor clamps and all includes locking screw thread, anchor clamps overcoat and cyclic annular clamp splice down, wherein: the clamp outer sleeve is formed by hermetically connecting a clamp head shell and an end cover, the clamp head shell and the end cover are both provided with a step-shaped annular cavity, the annular clamping block is placed in the annular cavity of the clamp head shell and used for clamping a test sample, and a piston is accommodated in the annular cavity of the end cover; the annular clamping block is connected with the piston through a circular base plate; the piston can reciprocate along the axis of the annular clamping block under the action of hydraulic pressure, so that the annular clamping block is driven to clamp a test sample or release the test sample.
2. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 1, characterized in that: the locking thread is used for connecting the piston of the hydraulic clamp with a fatigue testing machine.
3. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 1, characterized in that: the piston of the hydraulic clamp is of a stepped structure, and the front end and the rear end of the piston are respectively in close contact with the inner wall of the annular cavity of the end cover; a first hydraulic cavity is formed between the front end of the piston and the stepped surface of the annular cavity of the end cover; meanwhile, a second hydraulic cavity is formed between the front end of the piston and the rear end face of the chuck shell; the first hydraulic cavity and the second hydraulic cavity are respectively connected with a pressure oil source through pipelines.
4. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 1, characterized in that: the piston is welded or connected with the round chassis through a bolt; the circular base plate is connected with the annular clamping blocks through bolts, annular protrusions are arranged on the circular base plate and clamped at the rear end threads of the annular clamping blocks, so that the stability of connection of the circular base plate and the annular clamping blocks is enhanced, and the consistency of axes is kept.
5. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 1, characterized in that: the contact surfaces of the annular cavity of the chuck shell and the annular clamping block are respectively provided with an internal thread and an external thread, and the annular clamping block is fixed in the clamp outer sleeve through the matching of the internal thread and the external thread.
6. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 5, wherein: the tooth form of the external thread on the annular clamping block is triangular, the angle alpha between the surface of the triangular tooth form close to the processing end and the axis of the annular clamping block is 15-30 degrees, and the angle beta between the surface of the triangular tooth form far away from the processing end and the axis of the annular clamping block is 60-75 degrees; the angle between the upper surface of the triangular tooth shape of the upper clamp and the axis of the annular clamping block is 60-75 degrees, and the angle between the lower surface of the triangular tooth shape and the axis of the annular clamping block is 15-30 degrees; the external diameter and pitch of the internal thread of the annular cavity of the chuck shell are matched with the internal diameter and pitch of the external thread.
7. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 2, wherein: the annular clamping block consists of three equally-divided petal-shaped clamping blocks, the included angle of each petal-shaped clamping block is 110 degrees, and the remaining 30-degree space is used for clamping a sample.
8. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 7, wherein: the material of cyclic annular clamp splice is the super high strength steel of hardness 60 ~ 65HRC, and cyclic annular clamp splice is direct and sample contact, and the contact surface of cyclic annular clamp splice and sample is that the plain noodles does not have the sawtooth line, can guarantee not harm the sample surface when centre gripping sample.
9. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 1, characterized in that: when the hydraulic clamp works, liquid is fed into the first hydraulic cavity and pressurized, and the piston is driven to move towards the clamping end, so that the annular clamping blocks are pushed to approach towards the axial direction, and a sample is clamped; and the liquid is fed into the second hydraulic cavity and pressurized, and the piston is driven to move towards the position far away from the clamping end, so that the sample is released.
10. The hydraulic clamp for the electro-hydraulic servo fatigue testing machine according to claim 1, characterized in that: and the clamp jacket is provided with a cooling water inlet and a cooling water outlet which are connected with a cooling pipeline in the clamp jacket and used for circulating cooling water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110549864.9A CN113237741A (en) | 2021-05-20 | 2021-05-20 | Hydraulic clamp for electro-hydraulic servo fatigue testing machine |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110549864.9A CN113237741A (en) | 2021-05-20 | 2021-05-20 | Hydraulic clamp for electro-hydraulic servo fatigue testing machine |
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| CN113237741A true CN113237741A (en) | 2021-08-10 |
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| CN202110549864.9A Pending CN113237741A (en) | 2021-05-20 | 2021-05-20 | Hydraulic clamp for electro-hydraulic servo fatigue testing machine |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114324032A (en) * | 2021-12-20 | 2022-04-12 | 中机试验装备股份有限公司 | Be used for high temperature low cycle fatigue test anchor clamps |
| CN117433936A (en) * | 2023-12-19 | 2024-01-23 | 中航试金石检测科技(成都)有限公司 | Small sample low cycle fatigue testing device |
-
2021
- 2021-05-20 CN CN202110549864.9A patent/CN113237741A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114324032A (en) * | 2021-12-20 | 2022-04-12 | 中机试验装备股份有限公司 | Be used for high temperature low cycle fatigue test anchor clamps |
| CN117433936A (en) * | 2023-12-19 | 2024-01-23 | 中航试金石检测科技(成都)有限公司 | Small sample low cycle fatigue testing device |
| CN117433936B (en) * | 2023-12-19 | 2024-04-05 | 中航试金石检测科技(成都)有限公司 | Small sample low cycle fatigue testing device |
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