CN211528045U - A high temperature fatigue test fixture - Google Patents

Abstract

The utility model discloses a high temperature fatigue test fixture, which belongs to the technical field of high temperature fatigue test devices. The test fixture includes a base, an outer locking nut, an outer sleeve, a push rod, an inner locking nut and a replaceable clamping block; wherein: the base is provided with a push rod hole; The cylinder and the base are fixed together, and the ejector rod extends into the outer sleeve; the upper end of the ejector rod is provided with a cylindrical boss, and the upper part of the replaceable clamping block is used for screwing into the sample to be tested. At the threaded end, the lower part of the replaceable clamping block is sleeved on the cylindrical boss of the ejector rod; the replaceable clamping block is fixed on the outer sleeve through an internal locking nut. Through the improvement of the structure, the fixture can effectively avoid the gap between the sample and the high-temperature fixture during the test process, and the sample can continue to be locked during the test process, which greatly improves the test accuracy and accuracy of the high-temperature fatigue test. .

Description

A high temperature fatigue test fixture

technical field

The utility model relates to the technical field of high-temperature fatigue test devices, in particular to a high-temperature fatigue test fixture.

Background technique

Component failure caused by metal fatigue accounts for about 80% of all component failures. Fatigue fracture of metal components often has the characteristics of sudden and catastrophic. Aviation disasters caused by component failure have always existed with the appearance of aircraft. Every time an air accident occurs, serious political and economic problems will arise. The fatigue research of materials is the most important. As a key component of an aircraft, the role of aero-engines is self-evident. Once the engine fails and damages during operation, the consequences will be unimaginable. Since the working characteristics of the engine are high temperature, high speed and frequent starting, the high temperature and low cycle fatigue test for aero-engine materials is more important.

The locking device of the traditional mechanical high-temperature fixture is located in the high-temperature furnace. During the experiment, it is impossible to open the high-temperature furnace and then lock the sample twice. Once a gap occurs during the high-temperature tensile-compression fatigue test, we cannot. If the gap is effectively eliminated, the stress condition of the material near the zero point will change abruptly. On the one hand, the experimental data will be inaccurate.

Another disadvantage of the traditional high-temperature fixture is that the sample is directly screwed on the high-temperature fixture, and the thread connecting the traditional high-temperature fixture and the sample is directly processed on the high-temperature fixture and cannot be replaced. With the increase of use time, it is inevitable that the thread will be damaged. However, because the thread is integrated with the traditional high-temperature fixture, it can only be repaired and cannot be replaced. Once the thread cannot be repaired, the high-temperature fixture will be scrapped. On the one hand, it takes a long time to re-manufacture the high-temperature fixture, which affects the test progress, and on the other hand, the production cost of the high-temperature fixture is high.

In order to improve the test accuracy of the material in the high temperature and low cycle fatigue test, it is urgent to develop a fixture that can continuously lock the sample during the test process, in order to more truly reflect the life of the material under the working environment conditions, for the follow-up Component design provides a reliable reference.

Utility model content

The purpose of the utility model is to provide a high temperature fatigue test fixture, which can effectively avoid the gap between the sample and the high temperature fixture during the test process through the improvement of the structure, and can continue to lock the sample during the test process. , which greatly improves the test precision and accuracy of high temperature fatigue test. The high temperature fatigue test fixture also has the characteristics of simple operation and convenient maintenance.

For achieving the above object, the technical scheme adopted by the present utility model is as follows:

A high-temperature fatigue test fixture includes a base, an outer locking nut, an outer sleeve, a top rod, an inner locking nut and a replaceable clamping block; wherein: the base is provided with a cylindrical boss, and the upper surface of the boss is A mandrel hole is provided; the outer sleeve is installed on the base, the outer sleeve and the boss of the base are fixed together by an external locking nut, and the mandrel extends into the outer sleeve; The upper end of the ejector rod is provided with a cylindrical boss, the upper part of the replaceable clamping block is used for screwing into the threaded end of the sample to be tested, and the lower part of the replaceable clamping block is sleeved on the cylindrical boss of the ejector rod; After the lower end of the replaceable clamping block is sleeved on the upper end of the ejector rod, the replaceable clamping block is fixed on the outer sleeve through the inner locking nut.

The side surface of the cylindrical boss is provided with an external thread, the external locking nut is provided with an internal thread, and the external locking nut and the cylindrical boss are detachably connected through thread matching; the outer sleeve There is an annular boss on the outer side of the lower part of the outer locking nut, and the inner upper part of the outer locking nut is also provided with an annular boss; the annular boss on the inner side of the outer locking nut overlaps the annular boss on the outer side of the outer sleeve. On the boss, the relative position of the outer locking nut and the outer sleeve is fixed.

The top rod extends into the outer sleeve, and the lower end surface of the top rod extends into the top rod hole and fits with the bottom surface of the top rod hole.

The replaceable clamping block has a connected upper inner hole and a lower inner hole, and the upper inner hole has an inner thread, which is used for screwing into the threaded end of the sample to be tested, and screwed in until the end of the sample slightly protrudes from the upper part. The inner hole; the lower inner hole is sleeved on the cylindrical boss of the ejector rod; the diameter D1 of the upper inner hole of the replaceable clamping block is smaller than the diameter D2 of the lower inner hole, and the diameter of the cylindrical boss of the ejector rod is between D1 and D2.

The threaded end of the sample to be tested is screwed into the upper inner hole of the replaceable clamping block and slightly protrudes, so as to fit with the upper end surface of the cylindrical boss of the ejector rod.

The upper part of the outer sleeve is provided with an inner thread, the inner locking nut is provided with an upper inner hole and a lower inner hole, and the upper part of the inner locking nut is sleeved on the upper part of the replaceable clamping block; the The lower part of the inner locking nut is provided with an inner thread, and the upper part of the outer sleeve and the inner locking nut are detachably connected by thread fit.

The test fixture is used in two sets, one is used to clamp the upper end of the sample (upper clamp), and the other is used to clamp the lower end of the sample (lower clamp). , the outer lock nut is outside the high temperature furnace. During the test, by tightening the outer lock nut, there can be no gap between the sample and the fixture.

The advantages and beneficial effects of the present utility model are as follows:

The utility model redesigns the high temperature fatigue test fixture, which greatly improves the shortcomings of the traditional fixture, can effectively avoid the occurrence of gaps in the experiment process, and greatly improves the test precision and accuracy of the high temperature fatigue test. And standardize the thread matched with the fixture, once the thread is damaged, the thread can be quickly replaced, saving time and cost, and improving the test efficiency.

(1) Design of high-temperature fixture: The traditional high-temperature fixture has only one locking device, and the locking device is located in the high-temperature furnace. The new high-temperature fixture is structurally optimized on the basis of the traditional fixture, which turns the traditional solid high-temperature fixture into a hollow one. In the middle, the superalloy rod is passed through as the test bearing, and the fixture is changed into two locking devices without changing the structural rigidity of the high-temperature fixture. One is located in the high-temperature furnace and is used for locking when installing the sample. The other is located outside the high-temperature furnace. After the high-temperature furnace is installed, the gap caused by the different expansion coefficients of the sample and the fixture and the deformation of the sample during the loading process is externally locked to completely eliminate the gap. This leads to inaccurate experimental results and potential safety hazards of experimental equipment.

(2) Removable sample thread clamp: The thread on the traditional high temperature fixture is changed to make the sample thread clamp into a detachable type. The sample thread clamp block is locked on the high temperature fixture by an extra large nut. At the same time, some commonly used sample thread clamps are processed as spares. When the sample thread clamps are damaged during use, the test can be continued by replacing the spare thread clamps directly and quickly, which greatly improves the test efficiency and reduces the Maintenance costs of experimental equipment.

Description of drawings

FIG. 1 is a schematic structural diagram of a high-temperature fatigue test fixture of the present invention.

Figure 2 is a schematic diagram of the connection between the outer sleeve, the base and the outer locking nut in the high temperature fatigue test fixture of the present invention.

Fig. 3 is the base structure in the high temperature fatigue test fixture of the present invention.

Figure 4 shows the structure of the external locking nut in the high temperature fatigue test fixture of the present invention.

Fig. 5 is the round bar sample that the utility model is aimed at.

Among them: 1-base; 101-cylindrical boss; 102-top rod hole; 2-external lock nut; 3-outer sleeve; 4-top rod; 5-replaceable clamping block; 6-internal screw nut ; 7-round bar sample; 8-ring boss.

Detailed ways

The present utility model will be described in detail below in conjunction with the accompanying drawings.

The utility model is mainly designed for the high temperature fatigue fixture suitable for the round bar sample 7. During the test, the whole set of fixtures includes two fixtures of the utility model, which are divided into an upper fixture and a lower fixture.

As shown in Figures 1-5, the high temperature fatigue test fixture includes a base 1, an outer lock nut 2, an outer sleeve 3, a mandrel 4, an inner lock nut 6 and a replaceable clamping block 5; the specific structure and connection of each part The relationship is as follows:

As shown in Figure 2, the base 1 is provided with a cylindrical boss 101, the upper surface of the cylindrical boss is provided with a push rod hole 102; the outer surface of the cylindrical boss is provided with an external thread, the external lock The tightening nut is provided with an inner thread, and the outer locking nut and the cylindrical boss are detachably connected by thread matching; the outer side of the lower part of the outer sleeve is provided with an annular boss 8, and at the same time the outer locking nut is There is also an annular boss 8 on the upper part of the inner side; the annular boss on the inner side of the outer locking nut overlaps the annular boss on the outer side of the outer sleeve, so as to ensure that the outer sleeve is pressed by the outer locking nut It can be tightened without moving, and the relative position of the outer lock nut and the outer sleeve can be fixed.

The bottom end surface of the outer sleeve is provided with small protrusions, and the upper end surface of the cylindrical boss of the base is provided with a corresponding groove. When the outer sleeve is placed on the cylindrical boss, the outer sleeve The small protrusion on the upper just protrudes into the groove on the cylindrical boss to realize the relative fixation of the position of the outer sleeve and the base.

The top rod extends into the outer sleeve, and the lower end surface of the top rod extends into the top rod hole and fits with the bottom surface of the top rod hole.

The upper end of the ejector rod is provided with a cylindrical boss, the replaceable clamping block has an upper inner hole and a lower inner hole that are connected, and the upper inner hole has an inner thread for screwing into the threaded end of the sample to be tested, And screw it in until the end of the sample slightly protrudes from the upper inner hole; the lower inner hole is sleeved on the cylindrical boss of the ejector rod; the upper inner hole diameter D1 of the replaceable clamping block is smaller than the lower inner hole diameter D2, and the cylinder of the ejector rod The diameter of the shaped boss is between D1 and D2.

After the lower end of the replaceable clamping block is sleeved on the upper end of the ejector rod, the replaceable clamping block is fixed on the outer sleeve through the inner locking nut.

The threaded end of the sample to be tested is screwed into the upper inner hole of the replaceable clamping block and slightly protrudes, so as to fit with the upper end surface of the cylindrical boss of the ejector rod.

The upper part of the outer sleeve is provided with an inner thread, the inner locking nut is provided with an upper inner hole and a lower inner hole, and the upper part of the inner locking nut is sleeved on the upper part of the replaceable clamping block; the The lower part of the inner locking nut is provided with an inner thread, and the upper part of the outer sleeve and the inner locking nut are detachably connected through thread matching.

The test fixture is used in two sets, one is used to clamp the upper end of the sample (upper clamp), and the other is used to clamp the lower end of the sample (lower clamp). , the outer lock nut is outside the high temperature furnace. During the test, by tightening the outer lock nut, there can be no gap between the sample and the fixture.

The use process of the test fixture of the utility model is as follows:

(1) Process the sample according to the requirements of the drawing, and screw the threaded section of the sample with the measured size into the assembled lower high temperature fixture until it stops.

(2) Loosen the outer lock nut in reverse, then continue to screw the sample into the high temperature fixture, and finally lock the outer lock nut to ensure that the threaded end face of the sample withstands the high temperature ejector rod and there is no gap.

(3) Screw the replaceable clamp block of the upper fixture into the end of the sample thread until the thread of the replaceable clamp block is exposed to the end of the sample thread. Make sure that the top rod of the upper fixture can bear against the threaded end of the specimen.

(4) Install the upper fixture and the fatigue testing machine without gaps, and tighten the external locking nuts of the upper and lower fixtures when the preload of the sample is less than the test load.

(5) Set the fatigue test parameters as required and start the fatigue test.

The precautions when using the test fixture of the utility model are as follows:

1. It is required that the end face of the sample and the parallel section must be vertical.

2. During the installation of the sample, it must be ensured that the threaded part of the replaceable clamp block is exposed at the end of the thread and is tightly connected with the ejector rod without gaps.

3. The fixture cannot be used in environments containing corrosive media, and the operating temperature cannot exceed 1000 degrees.

4. During the high temperature test, cooling water must be used throughout the process to protect the fixture and testing machine.

After the high-temperature fatigue clamp of the utility model is used, the problem of clearance in the high-temperature fatigue process is effectively solved, and the use of the detachable threaded clamp can prolong the service life of the high-temperature clamp. It has been proved by practice that compared with the traditional high temperature fixture, the probability of gaps between the sample and the fixture during the experiment is reduced by more than 90%, which greatly improves the validity of the test data, avoids repeated tests, and reduces repetition. The problem of waste of resources brought by the test, and the cost of using the test machine is reduced.

Claims (7)

1. The utility model provides a high temperature fatigue test anchor clamps which characterized in that: the test fixture comprises a base, an external locking nut, an outer sleeve, a mandril, an internal locking nut and a replaceable clamping block; wherein: the base is provided with a cylindrical boss, and the upper surface of the boss is provided with a mandril hole; the outer sleeve is arranged on the base, the outer sleeve is fixed with the boss of the base through an external locking nut, and the ejector rod extends into the outer sleeve; the upper end of the ejector rod is provided with a cylindrical boss, the upper part of the replaceable clamping block is used for screwing in a threaded end of a sample to be tested, and the lower part of the replaceable clamping block is sleeved on the cylindrical boss of the ejector rod; and after the lower end of the replaceable clamping block is sleeved at the upper end of the ejector rod, the replaceable clamping block is fixed on the outer sleeve through the inner locking nut.

2. The high temperature fatigue test fixture of claim 1, wherein: the side surface of the cylindrical boss is provided with external threads, the external locking nut is provided with internal threads, and the external locking nut and the cylindrical boss are in threaded fit to realize detachable connection; the outer side of the lower part of the outer sleeve is provided with an annular boss, and the upper part of the inner side of the outer locking nut is also provided with an annular boss; the annular boss on the inner side of the external locking nut is lapped on the annular boss on the outer side of the outer sleeve, so that the relative position of the external locking nut and the outer sleeve is fixed.

3. The high temperature fatigue test fixture of claim 1, wherein: the ejector rod extends into the outer sleeve, and the lower end face of the ejector rod extends into the ejector rod hole and is attached to the bottom face of the ejector rod hole.

4. The high temperature fatigue test fixture of claim 1, wherein: the replaceable clamping block is provided with an upper inner hole and a lower inner hole which are communicated, the upper inner hole is provided with internal threads and is used for screwing in a threaded end of a sample to be tested until the end part of the sample slightly extends out of the upper inner hole; the lower inner hole is sleeved on the cylindrical boss of the ejector rod; the diameter D1 of the upper inner hole of the replaceable clamping block is smaller than the diameter D2 of the lower inner hole, and the diameter of the cylindrical boss of the ejector rod is between D1 and D2.

5. The high temperature fatigue test fixture of claim 4, wherein: and the threaded end of the sample to be tested is screwed into the inner hole at the upper part of the replaceable clamping block and slightly extends out, and is attached to the upper end face of the cylindrical boss of the ejector rod.

6. The high temperature fatigue test fixture of claim 4, wherein: the upper part of the outer sleeve is provided with internal threads, an upper inner hole and a lower inner hole are formed in the inner locking nut, and the upper part of the inner locking nut is sleeved on the upper part of the replaceable clamping block; the lower part of the inner locking nut is provided with internal threads, and the upper part of the outer sleeve is detachably connected with the inner locking nut through thread matching.

7. The high temperature fatigue test fixture of claim 1, wherein: the test fixture is used in a matched mode, one test fixture is used for clamping the upper end of a sample, the other test fixture is used for clamping the lower end of the sample, after the test fixture is placed in a high-temperature furnace, an inner locking nut of the test fixture is located in the high-temperature furnace, an outer locking nut is located outside the high-temperature furnace, and the test fixture can be free of gaps between the sample and the test fixture by tightening the outer locking nut in the test process.

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