CN112393890A

CN112393890A - Tension and compression load loading device and method for fatigue test

Info

Publication number: CN112393890A
Application number: CN202011309956.1A
Authority: CN
Inventors: 侯博之; 王小锋; 吕少力; 汪赵宏; 郭明玄; 周旺; 黎子峋; 曾庆凯
Original assignee: AVIC Landing Gear Advanced Manufacturing Corp
Current assignee: AVIC Landing Gear Advanced Manufacturing Corp
Priority date: 2020-11-20
Filing date: 2020-11-20
Publication date: 2021-02-23
Anticipated expiration: 2040-11-20
Also published as: CN112393890B

Abstract

The invention provides a tension and compression load loading device and method for a fatigue test. The tension-compression load loading device for the fatigue test comprises a supporting frame, a tension-compression rod, a base and a planetary gear mechanism arranged on the base, wherein a driving shaft of the planetary gear mechanism is offset relative to a vertical central line of the base; the tension and compression rods positioned on two sides of the planet wheel mechanism are supported by the supporting frame, and the tension and compression rods are connected with the outer ring of the planet wheel mechanism. Compared with the prior art, the tension-compression load loading device for the fatigue test is suitable for simulation and verification of the fatigue test, realizes fatigue loading of test pieces with different sizes by adopting a similar planetary gear mechanism, and solves the problems of complex operation and difficulty in ensuring loading precision in the fatigue process of the test pieces with different space sizes.

Description

Tension and compression load loading device and method for fatigue test

Technical Field

The invention relates to the technical field of general tests, in particular to a tension and compression load loading device and method for a fatigue test.

Background

For the fatigue test of parts, a hydraulic actuator cylinder is generally adopted to load or a motor is adopted to drive a cam to load. For some parts, the hydraulic actuating cylinder has complex loading test and high cost, and a matched hydraulic oil source and site are also needed. For the adoption of a motor to drive a cam to convert the up-and-down motion into the left-and-right loading motion, the up-and-down motion needs to design a slide rail along the vertical direction, and the left-and-right loading motion needs a traction rope and a steering pulley which can transmit load, the loading mode has high cost, the precision is not well ensured, and the stability is not strong.

Disclosure of Invention

The invention aims to provide a tension-compression load loading device and a method thereof for a fatigue test, which have the advantages of high precision, simple structure, no limitation on the size of a test piece and no occupation of too large space.

The technical scheme of the invention is as follows: a tension and compression load loading device for a fatigue test comprises a supporting frame, a tension and compression rod, a base and a planetary gear mechanism arranged on the base, wherein a driving shaft of the planetary gear mechanism is offset relative to a vertical central line of the base; the tension and compression rods positioned on two sides of the planet wheel mechanism are supported by the supporting frame, and the tension and compression rods are connected with the outer ring of the planet wheel mechanism.

In the scheme, the driving shaft is designed to be the planetary wheel mechanism with the offset structure, the rotation of the planetary wheel mechanism is converted into the outer linear motion of the tension and compression rod, so that the reciprocating loading of a fatigue test piece is realized, the loading characteristic test under the working condition of a complex fatigue test is completed, and the test efficiency is greatly improved.

In addition, in all mechanisms for converting rotation into external linear motion, the planetary wheel mechanism has high precision, simple operation, convenient use, no space occupation and high applicability and reliability, so the innovation point of the invention is that the required function is realized by using the planetary wheel mechanism with the advantages, thereby solving the problems of complex operation and difficult guarantee of loading precision in the fatigue process of test pieces with different space sizes.

Preferably, the planetary gear mechanism comprises a gear ring, a driving gear, two pinions and a gearwheel, and the driving gear, the pinions and the gearwheel are all meshed with the internal teeth of the gear ring; the driving gear is provided with the driving shaft; the two pinions all with drive gear meshing, the gear wheel simultaneously with two the pinion meshing, the outer lane of ring gear with the tension and compression bar is connected.

The specific structure in the planetary wheel mechanism realizes fatigue loading of test pieces with different sizes through the variable transmission ratio characteristic, so that the clamping jaw device can simulate different fatigue environments according to different test requirement conditions, thereby improving the test efficiency and greatly saving the test cost.

Preferably, the driving gear is an eccentric gear, an eccentric shaft of the eccentric gear is the driving shaft, a distance L1 is formed between the driving shaft and a vertical center line, a distance L2 is formed between an axial center line of the driving gear and the vertical center line, and L1 is less than L2. The structure design determines the position direction of the offset of the driving shaft, and the optimal transmission ratio can be obtained by setting the position direction of the offset of the driving shaft, so that a reliability loading test can be carried out.

Preferably, the gear ring comprises an inner ring, rollers and an outer ring, the inner ring is sleeved in the outer ring, a plurality of rollers are circumferentially arranged between the inner ring and the outer ring, and the rollers can enable the inner ring and the outer ring to relatively rotate; the inner ring is provided with inner teeth which are engaged with the driving gear, the pinion and the gearwheel, and the outer circular surface of the outer ring is fixedly connected with the tension and compression bar.

The gear ring is optimized in structure, the adjustment of the transmission ratio is facilitated, and the more accurate transmission ratio is obtained according to the fatigue loading of test pieces with different sizes.

Preferably, the planetary gear mechanism further comprises a rotating shaft and a roller, the roller is rotatably mounted in the base through the rotating shaft, and the roller is in contact with the outer circular surface of the planetary gear mechanism. And a roller is adopted to support the planet wheel mechanism.

Preferably, two rollers are symmetrically arranged relative to the vertical center line.

Preferably, the support frame supports an axial center line of the tension/compression bar at the same height position as the drive shaft. The position can make the linear movement distance of the tension and compression rod be maximum.

Preferably, the tension and compression rod is in contact with the support frame through half bearing bushes. Through the half bush of design, reduce the sliding friction between tension and compression pole and the braced frame.

The invention also provides a tension and compression load loading method for the fatigue test, which is carried out by adopting the tension and compression load loading device for the fatigue test and comprises the following steps:

connecting a motor with a driving shaft of the tension and compression load loading device for the fatigue test, adjusting parameters of the motor, connecting a tension and compression rod with a fatigue test piece, and starting the motor;

step two, when the offset driving shaft enables the planetary wheel mechanism to rotate, the position of the vertical central line of the planetary wheel mechanism changes, so that the planetary wheel mechanism pushes the tension and compression rod to perform reciprocating linear motion of moving left and right;

and step three, the left and right movement of the tension and compression rod pushes the fatigue test piece to carry out reciprocating loading, so that the loading characteristic test of the fatigue test is completed.

Preferably, the parameters for regulating the motor in the first step include amplitude and frequency, wherein the amplitude is equal to 2 x and the frequency is equal to motor speed ω ÷ 360.

Compared with the related technology, the invention has the beneficial effects that:

the fatigue loading device is suitable for simulation and verification of fatigue tests, realizes fatigue loading of test pieces with different sizes by adopting a similar planetary gear mechanism, and solves the problems of complex operation and difficulty in ensuring loading precision in the fatigue process of the test pieces with different spatial sizes;

through parameter design, the testing device can adapt to various fatigue tests, and cost is saved;

the testing device has the characteristics of high reliability, simplicity in operation and small occupied space, greatly improves the testing efficiency, and is convenient to implement and wide in adaptability.

Drawings

FIG. 1 is a schematic structural diagram of a tensile-compressive load loading device for fatigue tests provided by the invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a left side view of FIG. 1;

fig. 4 is an enlarged view of a part of the structure of the ring gear in fig. 1.

In the drawings: 1. a ring gear; 2. an eccentric gear; 3. a pinion gear; 4. a bull gear; 5. pulling and pressing the rod; 6. a support frame; 7. a motor; 8. half bearing shells; 9. a rotating shaft; 10. a roller; 11. a base; 1-1 gear ring inner ring; 1-2 rollers; 1-3 outer ring.

Detailed Description

The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings. It should be noted that the embodiments and features of the embodiments may be combined with each other without conflict. For convenience of description, the words "upper", "lower", "left" and "right" in the following description are used only to indicate the correspondence between the upper, lower, left and right directions of the drawings themselves, and do not limit the structure.

As shown in fig. 1 to 3, the tensile and compressive load loading device for fatigue test provided in this embodiment includes a supporting frame 6, a tensile and compressive rod 5, a motor 7, a base 11, and a planetary gear mechanism installed on the base 11.

The planet wheel mechanism comprises a gear ring 1, a driving gear 2, two pinions 3 and a gearwheel 4, wherein the driving gear 2, the pinions 3 and the gearwheel 4 are all meshed with the inner teeth of the gear ring 1. The two small gears 3 are meshed with the driving gear 2, and the large gear 4 is meshed with the two small gears 3 simultaneously.

The driving gear 2 is an eccentric wheel in the embodiment, and the driving shaft M is arranged on the driving gear 2. The drive shaft M is offset with respect to the vertical centerline H of the base 11. The direction of the bias is: the driving shaft M has a distance L1 with the vertical central line H, the driving gear 2 has a distance L2 with the axial central line H, and L1 < L2.

The tension and compression rods 5 positioned on the two sides of the planet wheel mechanism are supported by the supporting frame 6, and the axial center lines of the tension and compression rods 5 and the driving shaft M are positioned at the same height position. And the tension and compression rod 5 is fixedly connected with the outer circular surface of the gear ring 1 of the planetary gear mechanism.

Two rotating shafts 9 are supported in the base 11, and each rotating shaft 9 is sleeved with a roller 10. The rollers 10 are in contact with the outer circular surface of the gear ring 1, and the two rollers 10 are symmetrically arranged relative to the vertical central line H. The roller 10 is used for supporting the planetary gear mechanism and rotates together with the gear ring 1.

The fatigue loading of test pieces with different sizes is realized by utilizing the variable transmission ratio characteristic of the star gear mechanism, the test efficiency is improved, and the test cost is greatly saved.

As shown in fig. 3, the tension/compression bar 5 is in contact with the support frame 6 via half-shells 8. The drive shaft M is connected to an output shaft of the motor 7. The motor 7 drives the eccentric wheel to enable the gear ring 1 to drive the fixedly connected tension and compression rod 5 to move left and right, the rotation is converted into external linear motion, the tension and compression rod 5 drives the fatigue test piece to carry out reciprocating loading, and a loading characteristic test under a complex fatigue test working condition is completed.

As shown in fig. 4, the gear ring 1 includes an inner ring 1-1, rollers 1-2 and an outer ring 1-3, the inner ring 1-1 is sleeved in the outer ring 1-3, and a plurality of rollers 1-2 are circumferentially arranged between the inner ring 1-1 and the outer ring 1-3, and the plurality of rollers 1-2 can enable the inner ring 1-1 and the outer ring 1-3 to relatively rotate; the inner ring 1-1 is provided with inner teeth which are engaged with the driving gear 2, the pinion 3 and the gearwheel 4, and the outer circular surface of the outer ring 1-3 is fixedly connected with the tension and compression rod 5.

step one, connecting a motor with a driving shaft of the tension and compression load loading device for the fatigue test, adjusting parameters of the motor, connecting a tension and compression rod with a fatigue test piece, and starting the motor.

The parameters regulating the motor include amplitude, equal to 2 x (L2-L1), i.e. twice the eccentricity, and frequency, equal to the motor speed ω ÷ 360.

And step two, when the offset driving shaft enables the planetary wheel mechanism to rotate, the position of the vertical central line of the planetary wheel mechanism changes, so that the planetary wheel mechanism pushes the tension and compression rod to move leftwards and rightwards in a reciprocating linear motion.

The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A tension-compression load loading device for a fatigue test is characterized by comprising a supporting frame (6), a tension-compression rod (5), a base (11) and a planetary gear mechanism arranged on the base (11), wherein a driving shaft (M) of the planetary gear mechanism is offset relative to a vertical central line (H) of the base (11); the tension and compression rods (5) positioned on two sides of the planet wheel mechanism are supported by the supporting frame (6), and the tension and compression rods (5) are connected with the outer ring of the planet wheel mechanism.

2. The tension-compression load loading device for the fatigue test according to claim 1, wherein the planetary gear mechanism comprises a gear ring (1), a driving gear (2), two small gears (3) and a large gear (4), and the driving gear (2), the small gears (3) and the large gear (4) are all meshed with the internal teeth of the gear ring (1); the driving gear (2) is provided with the driving shaft (M); two pinion (3) all with drive gear (2) meshing, gear wheel (4) simultaneously with two pinion (3) meshing, the outer lane of ring gear (1) with draw depression bar (5) to be connected.

3. The tension-compression load loading device for fatigue test as recited in claim 2, wherein the driving gear (2) is an eccentric gear, an eccentric shaft of the eccentric gear is the driving shaft (M), the driving shaft (M) has a distance L1 from a vertical centerline (H), the driving gear (2) has a distance L2 from the axial centerline to the vertical centerline (H), and L1 < L2.

4. The tension-compression load loading device for the fatigue test is characterized in that the gear ring (1) comprises an inner ring (1-1), rollers (1-2) and an outer ring (1-3), the inner ring (1-1) is sleeved in the outer ring (1-3), a plurality of rollers (1-2) are circumferentially arranged between the inner ring (1-1) and the outer ring (1-3), and the rollers (1-2) can enable the inner ring (1-1) and the outer ring (1-3) to relatively rotate; the inner ring (1-1) is provided with inner teeth which are internally meshed with the driving gear (2), the pinion (3) and the gear wheel (4), and the outer circular surface of the outer ring (1-3) is fixedly connected with the tension and compression rod (5).

5. The tension-compression load loading device for the fatigue test according to any one of claims 1 to 4, further comprising a rotating shaft (9) and a roller (10), wherein the roller (10) is rotatably mounted in the base (11) through the rotating shaft (9), and the roller (10) is in contact with an outer ring of the planetary gear mechanism.

6. The tension-compression load loading device for the fatigue test as recited in claim 5, wherein two rollers (10) are symmetrically arranged with respect to a vertical center line (H).

7. The tension-compression load loading device for the fatigue test as recited in any one of claims 1 to 4, wherein the support frame (6) supports the axial center line of the tension-compression rod (5) at the same height position as the drive shaft (M).

8. A tension-compression load loading device for a fatigue test according to any one of claims 1 to 4, wherein the tension-compression rod (5) is in contact with the support frame (6) through half bushes (8).

9. A tension and compression load loading method for a fatigue test is carried out by adopting the tension and compression load loading device for the fatigue test according to any one of claims 1 to 8, and is characterized by comprising the following steps:

10. The method of claim 9, wherein the parameters of the motor regulated in the first step include amplitude and frequency, the amplitude is equal to 2 x (L2-L1), and the frequency is equal to motor speed ω ÷ 360.