CN110823730A - Parallel loading type blade bending fatigue test device - Google Patents
Parallel loading type blade bending fatigue test device Download PDFInfo
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- CN110823730A CN110823730A CN201910853339.9A CN201910853339A CN110823730A CN 110823730 A CN110823730 A CN 110823730A CN 201910853339 A CN201910853339 A CN 201910853339A CN 110823730 A CN110823730 A CN 110823730A
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- 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
- G01N3/38—Investigating strength properties of solid materials by application of mechanical stress by applying repeated or pulsating forces generated by electromagnetic means
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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
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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
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0001—Type of application of the stress
- G01N2203/0005—Repeated or cyclic
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0014—Type of force applied
- G01N2203/0023—Bending
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/003—Generation of the force
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N2203/00—Investigating strength properties of solid materials by application of mechanical stress
- G01N2203/0058—Kind of property studied
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Abstract
The invention discloses a parallel loading type blade bending fatigue test device which comprises a base, a motor driving module, a transmission rod and a test module, wherein the motor driving module is arranged on the base; the motor driving module comprises a motor, a first coupler, a speed reducer and a second coupler; the test module comprises N test units which are sequentially connected; the test unit comprises a crank rotating component, an exciting component, a rolling type chuck and a clamp component. The motor passes through first coupling joint reduction gear, and the reduction gear rethread second coupling conveys the moment of torsion that the motor produced to follow-up test unit's that connects in parallel each other crank rotating assembly, then drives the actuating lever that links to each other with the connecting rod and is straight reciprocating motion, stimulates a plurality of test piece simultaneously, can produce corresponding stable amplitude, reaches the effect of blade bending fatigue test. The invention can automatically balance the reciprocating torque, does not need to prepare a plurality of sets of clamps, and has the advantages of simple structure, stable operation process, convenient manufacture and maintenance, low cost, high working efficiency and the like.
Description
Technical Field
The invention relates to the technical field of fatigue test equipment, in particular to a parallel loading type blade bending fatigue test device.
Background
In actual work and production, a plurality of components and parts are damaged under the action of alternating stress, such as meshing damage of gears, breakage of crankshafts, breakage of connecting rods, failure of springs, breakage of blades, fatigue fracture accidents of relatively large bridges and the like. Statistical data indicate that about 70% of failures of mechanical parts are caused by fatigue, so that research on fatigue phenomena is very necessary. Scientific practical research shows that the service life of the part structure in actual production cannot be predicted and calculated by a theoretical method. Therefore, the fatigue test of the parts and the material members has very important practical significance for testing the fatigue fracture resistance.
The existing fatigue testing machine is generally large in size, large in energy consumption and high in price, and is not economical for researching the fatigue performance of a plurality of small samples. Most of the existing fatigue testing machines can only carry out the test of a single test piece, and the test of a large bending fatigue test is difficult to carry out. Therefore, it is very necessary to design a simple and economical testing device which can simultaneously test the bending fatigue performance of a plurality of test samples.
The invention patent with the application number of CN201810186960.X and the name of 'a miniature thin plate fatigue test device' discloses a fatigue test device for performing a bending fatigue test on a miniature thin plate sample by using a slider-crank mechanism, an excitation slide rod is fixedly connected with a clamping device at one end of the sample by a screw, and the deformation mode of the sample is controlled by using the combination of a spring and a press rod, so that the fatigue test device can well ensure the fatigue test state of the sample, is particularly suitable for the bending fatigue test of the miniature thin and soft sample, however, for a hard sample made of alloy and composite materials, the device can not ensure that the end of the press rod cannot move in the test process, and further greatly influences the accuracy of the test result; and because the size of the test piece is small, the test piece replacement process is complicated, only one test piece is loaded each time, the loading time is too long, and the working efficiency is low, so that the practical application of the test piece is limited to a great extent.
Disclosure of Invention
The invention aims to solve the technical problem that the defects in the background art are overcome, and the parallel loading type blade bending fatigue test device is provided to overcome the technical problems that a fatigue test object can only be a micro-thin and soft test piece, the test piece replacement process is complicated, and the common loading of a plurality of test pieces cannot be realized.
The invention adopts the following technical scheme for solving the technical problems:
a parallel loading type blade bending fatigue test device comprises a base, a motor driving module, a transmission rod and a test module, wherein the motor driving module and the test module are fixed on the base;
the motor driving module comprises a motor, a first coupler, a speed reducer and a second coupler; the input end of the speed reducer is connected with the output shaft of the motor through a first coupler, and the output end of the speed reducer is connected with one end of the transmission rod through a second coupler;
the test module comprises N test units which are sequentially connected, wherein N is a natural number which is more than or equal to 1;
the test unit comprises a crank rotating component, an exciting component, a rolling type chuck and a clamp component;
the crank rotating assembly comprises a first rolling bearing, a first bearing seat, a transmission shaft and a crank;
the crank is U-shaped and comprises a first crank arm, a second crank arm and a journal, wherein the first crank arm and the second crank arm are arranged in parallel; two ends of the journal are respectively and vertically fixedly connected with the tails of the first crank arm and the second crank arm;
the first rolling bearing is fixed on the base through a first bearing seat; the transmission shaft penetrates through the inner ring of the first rolling bearing and is fixedly connected with the inner ring of the first rolling bearing, and one end of the transmission shaft is vertically and fixedly connected with the outer side of the root part of the second crank arm;
the excitation assembly comprises a connecting rod, an excitation rod, a first linear bearing, a second bearing seat, a third bearing seat, a second rolling bearing, a third rolling bearing, a fourth rolling bearing, a gasket, a locking bolt and a locking nut;
the connecting rod comprises a connecting rod body, a first connecting ring and a second connecting ring, the first connecting ring and the second connecting ring are both annular, two ends of the connecting rod body are fixedly connected with the outer walls of the first connecting ring and the second connecting ring respectively, and the straight line where the connecting rod body is located passes through the circle centers of the first connecting ring and the second connecting ring;
the excitation rod comprises an excitation rod body and a third connecting ring, the third connecting ring is annular, one end of the excitation rod body is fixedly connected with the outer wall of the third connecting ring, and the straight line where the excitation rod body is located passes through the circle center of the third connecting ring;
the second rolling bearing is sleeved on the journal, the inner wall of the second rolling bearing is fixedly connected with the journal, and the outer wall of the second rolling bearing is fixedly connected with the inner wall of the first connecting ring; the third rolling bearing is arranged in the second connecting ring, and the outer ring of the third rolling bearing is fixedly connected with the inner wall of the second connecting ring; the fourth rolling bearing is arranged in the third connecting ring, and the outer ring of the fourth rolling bearing is fixedly connected with the inner wall of the third connecting ring; the locking bolt sequentially penetrates through the inner ring of the third rolling bearing, the washer and the inner ring of the fourth rolling bearing and then is in threaded connection with the locking nut, so that the inner ring of the third rolling bearing, the washer and the inner ring of the fourth rolling bearing are locked; a gap is reserved between the outer ring of the third rolling bearing and the outer ring of the fourth rolling bearing;
the first linear bearing and the second linear bearing are sleeved on the exciting rod and are fixed on the base through a second bearing seat and a third bearing seat respectively;
the rolling type chuck comprises a frame, a first roller and a second roller;
the frame is shaped like a Chinese character 'kou';
the first roller and the second roller respectively comprise a central rod and a plurality of deep groove ball rolling bearings, wherein the deep groove ball rolling bearings are uniformly arranged on the central rod, and the inner rings of the deep groove ball rolling bearings are fixedly connected with the central rod;
the first roller and the second roller are arranged in the frame in parallel, and two ends of the central rod of the first roller and the central rod of the second roller are fixedly connected with the frame; and the clearance between the first roller and the second roller is larger than the thickness of the test piece;
the frame is fixedly connected with one end, away from the third connecting ring, of the exciting rod;
the clamp assembly comprises a fixed seat, a movable clamping piece, a first limiting block, a second limiting block, a first limiting bolt, a second limiting bolt and a plurality of fixing bolts;
the base is provided with a sliding chute perpendicular to the plane of the frame, and a sliding block is arranged in the sliding chute;
the bottom of the fixed seat is fixedly connected with the sliding block, so that the fixed seat can freely slide along the sliding groove;
the first limiting block and the second limiting block are respectively arranged at two ends of the sliding chute, and threaded holes with axes parallel to the straight line where the sliding chute is located are formed in the centers of the first limiting block and the second limiting block;
the first limiting bolt and the second limiting bolt are respectively in threaded connection with the threaded holes of the first limiting block and the second limiting block, and respectively penetrate through the threaded holes of the first limiting block and the second limiting block to be abutted against two sides of the fixing seat, so that the first limiting bolt and the second limiting bolt are matched with each other to limit the fixing seat;
a plurality of threaded holes matched with the fixing bolts are uniformly formed in the side wall of the fixing seat, a plurality of through holes in one-to-one correspondence with the threaded holes in the side wall of the fixing seat are correspondingly formed in the movable clamping piece, and the movable clamping piece is connected with the fixing seat through the plurality of fixing bolts; the movable clamping piece is used for being matched with the fixed seat to fix one end of the test piece, so that the test piece is parallel to the sliding groove;
the clamp assembly is used for fixing one end of a test piece and adjusting the other end of the test piece to be between the first roller and the second roller of the rolling type chuck; the crank is used for driving the connecting rod to generate displacement and transmit the displacement to the excitation rod piece during rotation, so that the drum-type chuck is driven to perform stable reciprocating motion, and a fatigue test is performed on a test piece;
in the N test units, the outer side of the root part of a first crank arm of a first test unit is vertically and fixedly connected with one end, far away from the second coupler, of a transmission rod, the outer side of the root part of a first crank arm of an Mth test unit is vertically and fixedly connected with one end, far away from the second coupler, of a transmission shaft of an M-1 test unit, M is a natural number which is more than or equal to 2 and less than or equal to N, and the transmission rod is coaxial with the transmission shafts of the N test units.
As a further optimization scheme of the parallel loading type blade bending fatigue testing device, the motor adopts a three-phase alternating current variable frequency motor.
As a further optimization scheme of the parallel loading type blade bending fatigue testing device, the number of the testing units is 4.
As a further optimization scheme of the parallel loading type blade bending fatigue testing device, the 4 testing units are symmetrical about the axis of the transmission rod.
As a further optimization scheme of the parallel loading type blade bending fatigue testing device, the transmission rod and the second coupling are connected through a key.
As a further optimization scheme of the parallel loading type blade bending fatigue testing device, in the testing unit, two ends of a transmission shaft are square, square holes matched with the end parts of the transmission shaft are formed in the root parts of a first crank arm and a second crank arm, the square holes in the root parts of the transmission shaft and the second crank arm are matched and connected to transmit torque, and the transmission shaft and the second crank arm are fastened through pins to limit axial relative motion;
the transmission shaft of the test unit is matched and connected with the square hole at the root part of the first crank arm of the adjacent test unit to transmit torque, and the transmission shaft is fastened through a pin to limit the axial relative motion of the transmission shaft and the square hole.
As a further optimization scheme of the parallel loading type blade bending fatigue testing device, a frame of the roller type chuck is made of a light fatigue-resistant metal material.
As a further optimization scheme of the parallel loading type blade bending fatigue testing device, a frame of the roller type chuck is made of aluminum alloy.
Starting a motor, transmitting torque through a speed reducer, achieving excitation frequency required by a test, keeping stable, starting to simultaneously perform bending fatigue test on a plurality of test pieces until one test piece is broken or meets the requirement required by the test, stopping the test, taking down the corresponding test piece, continuing starting up until all the test pieces meet the requirement required by the test, and sequentially recording readings of the corresponding counter when the test is stopped each time.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
1. the fatigue testing device is excited by adopting a crank-link mechanism, so that the working principle is simpler, the operation is convenient, the parts are convenient to disassemble and maintain, and the manufacturing and maintaining cost is lower;
2. by symmetrically and parallelly mounting the crank link mechanisms, the rotating inertia force and moment can be automatically balanced and offset when the device operates normally, vibration is reduced, and the stability of the transmission process is ensured;
3. because the fatigue test device adopts a parallel crank connecting rod form, a plurality of test pieces are subjected to bending fatigue test at the same time, the working time is saved, and the working efficiency is improved;
4. the end part of the excitation rod piece adopts the movable roller type chuck, so that the displacement accuracy of the test piece in the bending fatigue loading process is ensured, parts do not need to be disassembled when the test piece is replaced, and the operation is convenient and simple;
5. because the clamp assembly of the fatigue test device is adjustable, a test piece with the size and specification within a certain range can be subjected to a fatigue test on the tester without preparing a plurality of sets of clamps, so that the test cost is greatly reduced.
Drawings
FIG. 1 is an overall three-dimensional schematic diagram of an embodiment of the present invention;
fig. 2(a) and 2(b) are an overall three-dimensional schematic view and a top view of the motor driving module of the present invention, respectively;
FIG. 3 is a three-dimensional schematic view of the interaction between the crank rotating assembly and the drive link of each test unit of the present invention;
FIGS. 4(a), 4(b), and 4(c) are front, left, and top views, respectively, of the engagement between the crank rotating assembly and the drive link of the first test unit of the present invention;
FIG. 5 is a three-dimensional schematic view of the interaction of the drive assembly and the rolling chuck of the test unit of the present invention;
FIGS. 6(a) and 6(b) are an overall three-dimensional schematic view and a top view of a connecting rod and an exciting rod of the testing unit of the present invention;
FIG. 7 is a three-dimensional schematic view of a clamp assembly of the present invention;
fig. 8(a) and 8(b) are a front view and an axial view, respectively, of a force balance analysis of a 4-unit test cell crank rotation assembly in an embodiment of the present invention.
In the figure, 1-motor, 2-first coupling, 3-reducer, 4-second coupling, 5-drive rod, 6-crank, 7-first rolling bearing, 8-first bearing seat, 9-first crank arm, 10-second crank arm of first test unit, 11-journal of first test unit, 12-square hole at root of second crank arm of first test unit, 13-pin, 14-connecting rod, 15-exciting rod, 16-first linear bearing, 17-second bearing seat, 18-frame, 19-second roller, 20-second rolling bearing, 21-locking bolt, 22-locking nut, 23-gasket, 24-third rolling bearing, 25-fourth rolling bearing, 25-a fixed seat, 26-a movable clamping piece, 27-a fixed bolt, 28-a first limiting block, 29-a first limiting bolt and 30-a test piece.
Detailed Description
In order to make the technical solutions of the present invention better understood, the present invention will be described in further detail with reference to the accompanying drawings and specific embodiments. Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention. As used herein, the singular forms "a", "an", "the" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It will be understood that when an element is referred to as being "connected" or "coupled" to another element, it can be directly connected or coupled to the other element or intervening elements may also be present. Further, "connected" or "coupled" as used herein may include wirelessly connected or coupled. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
As shown in FIG. 1, the invention discloses a parallel loading type blade bending fatigue test device, which comprises a base, a motor driving module, a transmission rod and a test module, wherein the motor driving module and the test module are both fixed on the base.
As shown in fig. 2(a) and 2(b), the motor driving module includes a motor, a first coupling, a reducer, and a second coupling; the input of reduction gear through first shaft coupling with the output shaft of motor links to each other, the output of reduction gear through the second shaft coupling with the one end of transfer line links to each other.
The test module comprises N test units which are sequentially connected, wherein N is a natural number which is more than or equal to 1; the test unit comprises a crank rotating component, an exciting component, a rolling type chuck and a clamp component.
As shown in fig. 3, the crank rotating assembly includes a first rolling bearing, a first bearing seat, a transmission shaft and a crank;
the crank is U-shaped and comprises a first crank arm, a second crank arm and a journal, wherein the first crank arm and the second crank arm are arranged in parallel; two ends of the journal are respectively and vertically fixedly connected with the tails of the first crank arm and the second crank arm;
the first rolling bearing is fixed on the base through a first bearing seat; the transmission shaft penetrates through the inner ring of the first rolling bearing and is fixedly connected with the inner ring of the first rolling bearing, and one end of the transmission shaft is vertically and fixedly connected with the outer side of the root part of the second crank arm.
As shown in fig. 5, the exciting assembly includes a connecting rod, an exciting rod, a first linear bearing, a second bearing housing, a third bearing housing, a second rolling bearing, a third rolling bearing, a fourth rolling bearing, a washer, a locking bolt, and a locking nut.
As shown in fig. 6(a) and 6(b), the connecting rod includes a connecting rod body, a first connecting ring and a second connecting ring, the first connecting ring and the second connecting ring are both annular, two ends of the connecting rod body are respectively fixedly connected with outer walls of the first connecting ring and the second connecting ring, and a straight line where the connecting rod body is located passes through centers of the first connecting ring and the second connecting ring;
the excitation rod comprises an excitation rod body and a third connecting ring, the third connecting ring is annular, one end of the excitation rod body is fixedly connected with the outer wall of the third connecting ring, and the straight line where the excitation rod body is located passes through the circle center of the third connecting ring;
the second rolling bearing is sleeved on the journal, the inner wall of the second rolling bearing is fixedly connected with the journal, and the outer wall of the second rolling bearing is fixedly connected with the inner wall of the first connecting ring; the third rolling bearing is arranged in the second connecting ring, and the outer ring of the third rolling bearing is fixedly connected with the inner wall of the second connecting ring; the fourth rolling bearing is arranged in the third connecting ring, and the outer ring of the fourth rolling bearing is fixedly connected with the inner wall of the third connecting ring; the locking bolt sequentially penetrates through the inner ring of the third rolling bearing, the washer and the inner ring of the fourth rolling bearing and then is in threaded connection with the locking nut, so that the inner ring of the third rolling bearing, the washer and the inner ring of the fourth rolling bearing are locked; and a gap is reserved between the outer ring of the third rolling bearing and the outer ring of the fourth rolling bearing.
The first linear bearing and the second linear bearing are sleeved on the exciting rod and fixed on the base through the second bearing seat and the third bearing seat respectively.
The rolling type chuck comprises a frame, a first roller and a second roller; the frame is shaped like a Chinese character 'kou';
the first roller and the second roller respectively comprise a central rod and a plurality of deep groove ball rolling bearings, wherein the deep groove ball rolling bearings are uniformly arranged on the central rod, and the inner rings of the deep groove ball rolling bearings are fixedly connected with the central rod;
the first roller and the second roller are arranged in the frame in parallel, and two ends of the central rod of the first roller and the central rod of the second roller are fixedly connected with the frame; and the clearance between the first roller and the second roller is larger than the thickness of the test piece;
and the frame is fixedly connected with one end of the excitation rod away from the third connecting ring.
As shown in fig. 7, the clamp assembly includes a fixing seat, a movable clamping piece, a first limiting block, a second limiting block, a first limiting bolt, a second limiting bolt and a plurality of fixing bolts;
the base is provided with a sliding chute perpendicular to the plane of the frame, and a sliding block is arranged in the sliding chute;
the bottom of the fixed seat is fixedly connected with the sliding block, so that the fixed seat can freely slide along the sliding groove;
the first limiting block and the second limiting block are respectively arranged at two ends of the sliding chute, and threaded holes with axes parallel to the straight line where the sliding chute is located are formed in the centers of the first limiting block and the second limiting block;
the first limiting bolt and the second limiting bolt are respectively in threaded connection with the threaded holes of the first limiting block and the second limiting block, and respectively penetrate through the threaded holes of the first limiting block and the second limiting block to be abutted against two sides of the fixing seat, so that the first limiting bolt and the second limiting bolt are matched with each other to limit the fixing seat;
a plurality of threaded holes matched with the fixing bolts are uniformly formed in the side wall of the fixing seat, a plurality of through holes in one-to-one correspondence with the threaded holes in the side wall of the fixing seat are correspondingly formed in the movable clamping piece, and the movable clamping piece is connected with the fixing seat through the plurality of fixing bolts; the movable clamping piece is used for being matched with the fixed seat to fix one end of the test piece, so that the test piece is parallel to the sliding groove.
The clamp assembly is used for fixing one end of a test piece and adjusting the other end of the test piece to be between the first roller and the second roller of the rolling type chuck; the crank is used for driving the connecting rod to generate displacement and transmit the displacement to the excitation rod piece during rotation, so that the drum-type chuck is driven to perform stable reciprocating motion, and a fatigue test is performed on a test piece;
in the N test units, the outer side of the root part of a first crank arm of a first test unit is vertically and fixedly connected with one end, far away from the second coupler, of a transmission rod, the outer side of the root part of a first crank arm of an Mth test unit is vertically and fixedly connected with one end, far away from the second coupler, of a transmission shaft of an M-1 test unit, M is a natural number which is more than or equal to 2 and less than or equal to N, and the transmission rod is coaxial with the transmission shafts of the N test units.
The motor adopts a three-phase alternating-current variable-frequency motor, the number of the test units is 4, and the 4 test units are symmetrical about the axis of the transmission rod; the transmission rod and the second coupling are connected through a key.
In the test unit, two ends of a transmission shaft are square, square holes matched with the end parts of the transmission shaft are formed in the root parts of a first crank arm and a second crank arm, the square holes in the root parts of the transmission shaft and the second crank arm are matched and connected to transmit torque, and the transmission shaft and the second crank arm are fastened through pins to limit axial relative motion;
the test unit transmission shaft is matched and connected with a square hole at the root part of a first crank arm of an adjacent test unit to transmit torque, and the test unit transmission shaft is fastened through a pin to limit the axial relative motion of the test unit transmission shaft and the first crank arm of the adjacent test unit;
as shown in fig. 4(a), 4(b) and 4(c), the end of the transmission rod away from the second coupling is square, and the transmission rod is matched and connected with the square hole at the root part of the first crank arm of the first test unit so as to transmit torque, and is fastened by a pin to limit the axial relative movement of the transmission rod.
When the testing device works normally, the Hall sensor is adopted to convert the rotation information of the crank arm into a digital signal and transmit the digital signal to the digital display counter. The crank arm generates one pulse every time the crank arm rotates one circle, and the counter counts one time, so as to record the fatigue cycle number.
There is also a fatigue testing technique (reciprocating bending corrosion fatigue tester (CN201110124491.7)) in which an eccentric wheel on a main shaft is rotated by a crank-link mechanism, and a plurality of test pieces are subjected to reciprocating bending load by the eccentric wheel until the test pieces are broken. The bending fatigue testing machine can simultaneously carry out fatigue tests on a plurality of samples, and has high working efficiency, however, when the fatigue testing machine works normally, the fatigue testing machine cannot effectively balance the eccentric wheels during normal loading due to the asymmetrical serial connection structure of the eccentric wheels, so that partial vibration is caused, and the stability of the testing process is not facilitated; and this fatigue testing machine need adjust many parts when testing to the different specification samples of size, and operation process is comparatively loaded down with trivial details.
As shown in fig. 8(a) and 8(b), the force balance analysis method of the fatigue testing apparatus of the present embodiment is as follows:
the fatigue testing device of the embodiment is simplified into a four-crank connecting rod mechanism, and for the motion mechanism, the included angle between two adjacent cranks is 180 degrees. When the rotating shaft rotates around the central axis, the vertical direction projection of the rotating inertia force in a plane vertical to the central axis is as follows:
∑Pry＝mrrω2[cosα+cos(α+180°)+cos(α+180°)+cos α]＝0
and the horizontal projection of the rotating inertia force in a plane vertical to the central axis is as follows:
∑Prx＝mrrω2[sinα+sin(α+180°)+sin(α+180°)+sin α]＝0
wherein m isrFor the rotating mass, r is the crank radius, ω is the angular velocity of rotation, and α is the angle between the crank centerline and the vertical.
The resultant force of the rotational inertia forces is:
the projection of the rotational inertia resultant moment in the vertical direction in a plane vertical to the central axis is as follows:
and the horizontal projection of the rotational inertia resultant moment in a plane vertical to the central axis is as follows:
therefore, the total torque is:
∑Mr＝0。
in summary, in the case of the four-crank link mechanism, both the rotational inertia force and the rotational inertia moment are balanced during normal operation. Similarly, if the six-crank connecting rod mechanism is adopted, the included angle between adjacent cranks is 120 degrees, the total moment can be analyzed and obtained to be 0 according to the analysis method.
Simultaneously, compare the cost that ordinary MTS fatigue testing machine exists huge, need design complicated anchor clamps and lower work efficiency's defect, this fatigue test device anchor clamps are adjustable, consequently the test piece of size specification in certain extent all can carry out fatigue test on this testing machine, dismantle and install the sample convenient simple, when guaranteeing that self reaches balance in normal operation, the sample of the different specification and dimension of change that can be convenient again is experimental, work efficiency is high, the structure is also simple easy-to-use.
In the embodiment, the fixed seat and the movable clamping piece are connected and fastened through four bolts, the depth of a clamping area formed by the fixed seat and the movable clamping piece is 25-50 mm, and the depth of the clamping area is matched with a clamped part of the test piece, namely the length of the clamped part of the test piece is preferably 25-50 mm.
The maximum adjustable distance of the fixing seat is 10cm, so that test pieces with different lengths can be conveniently tested.
The drum-type chuck makes the test piece be the cantilever state all the time at the bending in-process, avoids the test piece to produce "S" type and warp, ensures experimental accuracy. The test can be carried out only when the thickness of the test piece is within the range of the clearance between the two rows of bearings.
The locking nut is preferably a self-locking nut, and can ensure that the connection is always kept fastened and stable in the high-speed transmission process. The number of the bearings in each roller of the roller type chuck can be selected from 10-12, the thickness of the test sample is mainly determined, the size of the gap between the two rows of bearings is determined by the thickness of the test sample, and the gap between the two rows of bearings can be changed by changing the distance between the cylindrical rod through holes in the roller type chuck, preferably 12-15 mm. The roller type chuck frame is made of light fatigue-resistant metal materials, such as aluminum alloy; the exciting rod can be made of bearing steel, and other parts can be made of structural steel.
When the device works, a motor is started, the speed is reduced through a speed reducer, the output torque is improved, the excitation frequency required by the test is achieved, the stability is kept unchanged, the bending fatigue test is started on the test pieces, the test is stopped until one of the test pieces is broken or the requirement required by the test is met, the corresponding test piece is taken down, the device is started continuously until all the test pieces meet the requirement required by the test, and the readings of the corresponding counter when the device is stopped each time are recorded in sequence.
In the test process, a strain gauge can be attached to the position, close to the fracture position of the test piece, strain of the position is monitored in real time through related computer analysis software, and the fracture characteristics of the test piece can be further analyzed. And related protection circuits can be designed, and when the test piece is broken or the strain reaches a certain limit value, the motor can be automatically stopped. In practical applications, the test piece size range in which the test can be performed: the length is 18-25 cm, the width is 6-10 cm, and the thickness is 2-10 mm.
In the embodiment, the torque generated by the motor is transmitted to the subsequent parallel crank-link mechanism through the speed reducer, then acts on each corresponding exciting rod to enable the exciting rod to simultaneously perform reciprocating linear motion in the horizontal direction, corresponding amplitude is generated, a plurality of test pieces are excited to simultaneously perform a bending fatigue test, and the working efficiency is obviously improved. The cantilever type test piece clamping part is cantilever type, so that the cantilever type test piece clamping part can be used for bending fatigue test of cantilever type test pieces. Because the fatigue test device adopts the crank link mechanism for excitation, the working principle is simpler, the operation is convenient, the parts are convenient to disassemble and maintain, and the manufacturing and maintaining cost is lower.
The rotating inertia force and the rotating inertia moment generated by the fatigue testing device in the embodiment during normal working operation can be automatically offset, so that the balance condition is met, and the stable transmission in the testing process is ensured. This fatigue test device anchor clamps are adjustable, therefore the test piece of size specification in certain extent all can carry out fatigue test on this testing machine, dismantle and install the convenient simple of sample, when guaranteeing that can normal operating self reaches balance, the sample of the different specification and dimension of change that can be convenient again is experimental, and the structure is also simple easy-to-use.
The embodiments in the present specification are described in a progressive manner, and the same and similar parts among the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. In particular, for the apparatus embodiment, since it is substantially similar to the method embodiment, it is relatively simple to describe, and reference may be made to some descriptions of the method embodiment for relevant points. The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A parallel loading type blade bending fatigue test device is characterized by comprising a base, a motor driving module, a transmission rod and a test module, wherein the motor driving module and the test module are both fixed on the base;
the motor driving module comprises a motor, a first coupler, a speed reducer and a second coupler; the input end of the speed reducer is connected with the output shaft of the motor through a first coupler, and the output end of the speed reducer is connected with one end of the transmission rod through a second coupler;
the test module comprises N test units which are sequentially connected, wherein N is a natural number which is more than or equal to 1;
the test unit comprises a crank rotating component, an exciting component, a rolling type chuck and a clamp component;
the crank rotating assembly comprises a first rolling bearing, a first bearing seat, a transmission shaft and a crank;
the crank is U-shaped and comprises a first crank arm, a second crank arm and a journal, wherein the first crank arm and the second crank arm are arranged in parallel; two ends of the journal are respectively and vertically fixedly connected with the tails of the first crank arm and the second crank arm;
the first rolling bearing is fixed on the base through a first bearing seat; the transmission shaft penetrates through the inner ring of the first rolling bearing and is fixedly connected with the inner ring of the first rolling bearing, and one end of the transmission shaft is vertically and fixedly connected with the outer side of the root part of the second crank arm;
the excitation assembly comprises a connecting rod, an excitation rod, a first linear bearing, a second bearing seat, a third bearing seat, a second rolling bearing, a third rolling bearing, a fourth rolling bearing, a gasket, a locking bolt and a locking nut;
the connecting rod comprises a connecting rod body, a first connecting ring and a second connecting ring, the first connecting ring and the second connecting ring are both annular, two ends of the connecting rod body are fixedly connected with the outer walls of the first connecting ring and the second connecting ring respectively, and the straight line where the connecting rod body is located passes through the circle centers of the first connecting ring and the second connecting ring;
the excitation rod comprises an excitation rod body and a third connecting ring, the third connecting ring is annular, one end of the excitation rod body is fixedly connected with the outer wall of the third connecting ring, and the straight line where the excitation rod body is located passes through the circle center of the third connecting ring;
the second rolling bearing is sleeved on the journal, the inner wall of the second rolling bearing is fixedly connected with the journal, and the outer wall of the second rolling bearing is fixedly connected with the inner wall of the first connecting ring; the third rolling bearing is arranged in the second connecting ring, and the outer ring of the third rolling bearing is fixedly connected with the inner wall of the second connecting ring; the fourth rolling bearing is arranged in the third connecting ring, and the outer ring of the fourth rolling bearing is fixedly connected with the inner wall of the third connecting ring; the locking bolt sequentially penetrates through the inner ring of the third rolling bearing, the washer and the inner ring of the fourth rolling bearing and then is in threaded connection with the locking nut, so that the inner ring of the third rolling bearing, the washer and the inner ring of the fourth rolling bearing are locked; a gap is reserved between the outer ring of the third rolling bearing and the outer ring of the fourth rolling bearing;
the first linear bearing and the second linear bearing are sleeved on the exciting rod and are fixed on the base through a second bearing seat and a third bearing seat respectively;
the rolling type chuck comprises a frame, a first roller and a second roller;
the frame is shaped like a Chinese character 'kou';
the first roller and the second roller respectively comprise a central rod and a plurality of deep groove ball rolling bearings, wherein the deep groove ball rolling bearings are uniformly arranged on the central rod, and the inner rings of the deep groove ball rolling bearings are fixedly connected with the central rod;
the first roller and the second roller are arranged in the frame in parallel, and two ends of the central rod of the first roller and the central rod of the second roller are fixedly connected with the frame; and the clearance between the first roller and the second roller is larger than the thickness of the test piece;
the frame is fixedly connected with one end, away from the third connecting ring, of the exciting rod;
the clamp assembly comprises a fixed seat, a movable clamping piece, a first limiting block, a second limiting block, a first limiting bolt, a second limiting bolt and a plurality of fixing bolts;
the base is provided with a sliding chute perpendicular to the plane of the frame, and a sliding block is arranged in the sliding chute;
the bottom of the fixed seat is fixedly connected with the sliding block, so that the fixed seat can freely slide along the sliding groove;
the first limiting block and the second limiting block are respectively arranged at two ends of the sliding chute, and threaded holes with axes parallel to the straight line where the sliding chute is located are formed in the centers of the first limiting block and the second limiting block;
the first limiting bolt and the second limiting bolt are respectively in threaded connection with the threaded holes of the first limiting block and the second limiting block, and respectively penetrate through the threaded holes of the first limiting block and the second limiting block to be abutted against two sides of the fixing seat, so that the first limiting bolt and the second limiting bolt are matched with each other to limit the fixing seat;
a plurality of threaded holes matched with the fixing bolts are uniformly formed in the side wall of the fixing seat, a plurality of through holes in one-to-one correspondence with the threaded holes in the side wall of the fixing seat are correspondingly formed in the movable clamping piece, and the movable clamping piece is connected with the fixing seat through the plurality of fixing bolts; the movable clamping piece is used for being matched with the fixed seat to fix one end of the test piece, so that the test piece is parallel to the sliding groove;
the clamp assembly is used for fixing one end of a test piece and adjusting the other end of the test piece to be between the first roller and the second roller of the rolling type chuck; the crank is used for driving the connecting rod to generate displacement and transmit the displacement to the excitation rod piece during rotation, so that the drum-type chuck is driven to perform stable reciprocating motion, and a fatigue test is performed on a test piece;
in the N test units, the outer side of the root part of a first crank arm of a first test unit is vertically and fixedly connected with one end, far away from the second coupler, of a transmission rod, the outer side of the root part of a first crank arm of an Mth test unit is vertically and fixedly connected with one end, far away from the second coupler, of a transmission shaft of an M-1 test unit, M is a natural number which is more than or equal to 2 and less than or equal to N, and the transmission rod is coaxial with the transmission shafts of the N test units.
2. The parallel loading type blade bending fatigue testing device as claimed in claim 1, wherein the motor is a three-phase alternating current variable frequency motor.
3. The parallel loading blade bending fatigue testing device of claim 1, wherein the number of the testing units is 4.
4. The parallel load blade bending fatigue testing device of claim 3, wherein the 4 test units are symmetric about the axis of the drive rod.
5. The parallel loading blade bending fatigue testing device of claim 1, wherein the transmission rod and the second coupling are connected by a key.
6. The parallel loading type blade bending fatigue testing device according to claim 1, wherein in the testing unit, two ends of a transmission shaft are square, square holes matched with the ends of the transmission shaft are formed in the root parts of a first crank arm and a second crank arm, and the square holes in the root parts of the transmission shaft and the second crank arm are matched and connected to transmit torque and are fastened through pins to limit axial relative movement of the transmission shaft and the second crank arm;
the transmission shaft of the test unit is matched and connected with the square hole at the root part of the first crank arm of the adjacent test unit to transmit torque, and the transmission shaft is fastened through a pin to limit the axial relative motion of the transmission shaft and the square hole.
7. The parallel loading blade bending fatigue testing device of claim 1, wherein the frame of the roller cartridge is made of a lightweight fatigue-resistant metal material.
8. The parallel loading blade bending fatigue testing device of claim 6, wherein the frame of the roller cartridge is made of aluminum alloy.
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| CN201910853339.9A CN110823730B (en) | 2019-09-10 | 2019-09-10 | Parallel loading type blade bending fatigue test device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN117405532A (en) * | 2023-12-12 | 2024-01-16 | 兰州理工大学 | Multifunctional fatigue testing device for blade |
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| CN110823730B (en) | 2021-06-15 |
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