JP6573577B2 - Fretting fatigue test apparatus and fretting fatigue test method - Google Patents

Description

  The present invention relates to a fretting fatigue test apparatus and a fretting fatigue test method.

  2. Description of the Related Art Conventionally, for example, in a device such as a turbine, a repeated load is applied to a constituent member such as a blade during operation, and reciprocal relative slip may occur between members adjacent to the constituent member. Such a phenomenon is known as so-called fretting fatigue, and causes a significant decrease in the fatigue strength of the constituent members.

Various fretting fatigue test apparatuses for evaluating the fatigue strength of members when such fretting fatigue occurs have been disclosed (for example, Patent Document 1 and Patent Document 2). Hereinafter, although the test apparatus disclosed by patent document 1 and patent document 2 is demonstrated, the code | symbol used by each patent document is shown with a parenthesis for reference.
The apparatus disclosed in Patent Document 1 (see paragraphs [0008]-[0010], FIG. 1) includes a spring plate (3) coupled to one end of the test piece (1) and the other end of the test piece (1). And the contact piece (2a), (2b) that contacts the side surface of the test piece (1), and the contact piece (2a), (2b) in the horizontal direction. It can be moved.

  In this apparatus, the contact force (pressing force) of the contact pieces (2a) and (2b) with respect to the test piece (1), the load (repetitive stress) applied to the test piece (1), and the test piece (1) and the contact piece The relative slip amount between (2a) and (2b) can be set arbitrarily. That is, by moving the contact pieces (2a) and (2b) in the horizontal direction to an appropriate position, the contact force of the contact pieces (2a) and (2b) with respect to the test piece (1) is changed to a desired contact force ( Pressing force), a desired load (repetitive stress) can be applied to the test piece (1) by the actuator, and the thickness of the spring plate (3) can be selected to select the test piece (1). An arbitrary relative slip amount can be given between the test piece (1) and the contact pieces (2a) and (2b) by arbitrarily changing the vertical movement.

  In the apparatus disclosed in Patent Document 2 (see paragraphs [0007] to [0008], FIG. 1 and the like), a blade dovetail test simulating a compressor blade on a wheel dovetail specimen (102) simulating a compressor wheel. With the pieces (101) fitted, the test pieces (101) and (102) are applied by applying axial forces (103) and (104) including variable loads to these test pieces (101) and (102). The fretting fatigue crack (106) is generated at the contact end (105) by sliding.

CD-ROM of the actual application No. 03-093123 (No. 05-36349) JP 2002-310867 A

However, in the actual machine, when relative slip occurs between two members and fretting fatigue occurs, the pressing force between these members (surface pressure acting between the members) may fluctuate while the relative slip occurs. In many cases, these members come into contact with each other. In other words, when the two members are in the one-sided contact state, there may be a case where relative sliding occurs between the members while the magnitude of the pressing force acting on the two members varies.
However, in the technique disclosed in Patent Document 1, although the contact force (pressing force) by the contact pieces (2a) and (2b) can be arbitrarily selected, the pressing force cannot be changed during the occurrence of relative slip. Further, the contact of the contact pieces (2a) and (2b) cannot be made per piece.
Even with the technique disclosed in Patent Document 2, the axial forces (103) and (104) that act on the test pieces (101) and (102), that is, the pressing force between the members can be changed, but the test piece (101). , (102) cannot be a single contact.

  The present invention has been devised in view of the above-described problems. The contact state between the contact piece and the test piece is set as a desired state, and the pressing force (surface pressure) of the contact piece on the test piece is changed. An object of the present invention is to provide a fretting fatigue test apparatus and a fretting fatigue test method capable of performing a fretting fatigue test by generating a relative slip between a contact piece and a test piece.

  (1) In order to achieve the above object, a fretting fatigue test apparatus according to the present invention includes a contact piece, a load applying unit that applies a repeated load to the contact piece in a first direction, and the contact piece. The test piece abutting from the second direction intersecting the first direction, the contact piece and the test piece are elastically restrained from the second direction, whereby the contact piece and the test piece are A pressing force applying mechanism for applying a pressing force at a predetermined pressing position; and a pressing position adjusting mechanism for adjusting the pressing position of the pressing force applying mechanism with respect to the first direction, the contact piece and the test piece The contact surface is set in a shape inclined with respect to the first direction.

  (2) It is preferable that a pair of the test pieces is provided on both sides of the contact piece so as to come into contact with the contact piece from both sides in the second direction.

  (3) The pressing force applying mechanism includes an annular body arranged so as to surround the test piece from the outside in the second direction, and is attached to the annular body, and directly or indirectly to each test piece. It is preferable to include a pressing force application member that applies a pressing force.

  (4) It is preferable that a pair of the pressing force application members are attached to the annular body toward the pair of test pieces.

  (5) It is provided on the inner peripheral side of the annular body and includes a test piece holding part for holding the test piece, and the test piece holding part has an outer peripheral part arranged on the outer peripheral side with respect to the held test piece. Each of the pair of pressing force imparting members is brought into contact with the outer peripheral portion at an arbitrary position with respect to the first direction so that the test piece is brought into contact with the contact piece via the outer peripheral portion. While pressing, it is fixed to the said outer peripheral part, and it is preferable that the said pressing position adjustment mechanism is provided with the said pair of pressing force provision member.

  (6) The outer peripheral portion of the test piece holding portion is provided with a plurality of concave portions into which the tip of the pressing force applying member is inserted along the first direction, and the pressing position adjusting mechanism includes the pair of pressing positions. It is preferable that the pressing force application member and the plurality of recesses are provided.

  (7) In order to achieve the above object, the fretting fatigue test method of the present invention uses the fretting fatigue test apparatus described in any one of (1) to (6) to apply the pressing force. The fretting fatigue test is performed by adjusting the pressing position of the mechanism with respect to the first direction and bringing the contact piece and the test piece into a one-piece contact state or a whole contact state.

In the present invention, the load is repeatedly applied to the contact piece in the first direction by the load applying unit, and the test piece comes into contact with the contact piece from the second direction intersecting the first direction. Then, by setting the contact surface between the test piece and the contact piece in a shape inclined with respect to the first direction, when the load application unit repeatedly applies a load to the contact piece in the first direction, Relative slip occurs in the inclined direction between the contact surfaces with the contact piece. Further, the test piece is elastically constrained by the pressing force applying mechanism, and the pressing position for applying the pressing force to the contact piece and the test piece by the pressing force applying mechanism is configured to be adjustable with respect to the first direction.
With such a configuration, by repeatedly applying a load in the first direction to the contact piece in the first direction, a relative slip is caused between the contact piece and the test piece while changing the pressing force on the test piece. The fretting fatigue test can be performed.
Furthermore, the degree of contact between the contact piece and the test piece can be changed as appropriate by appropriately changing the pressing position of the pressing force applying mechanism.
Therefore, while maintaining the contact condition between the contact piece and the test piece according to the actual situation in the actual machine (for example, the one-piece contact state or the entire contact state), and also changing the pressing force (surface pressure) A fretting fatigue test can be performed.

FIG. 3 is a schematic cross-sectional view showing the configuration of the fretting fatigue test apparatus according to one embodiment of the present invention, and is a cross-sectional view taken along the line CC in FIG. It is a typical longitudinal cross-sectional view which shows a structure to the fretting fatigue testing apparatus of one Embodiment of this invention, Comprising: (a) is AA sectional drawing of FIG. 1, (b) is BB sectional drawing of FIG. FIG. It is typical sectional drawing for demonstrating the principle of the fretting fatigue test apparatus of one Embodiment of this invention, Comprising: It is a longitudinal cross-sectional view which shows the principal part of a fretting fatigue test apparatus. It is a schematic diagram which shows the relationship of the various parameters in the fretting fatigue testing apparatus which concerns on one Embodiment of this invention to (a)-(h), respectively. BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram for demonstrating the relationship between the load point distance which concerns on one Embodiment of this invention, a contact range length, and a contact area, Comprising: It is a principal part front view of a fretting fatigue test apparatus, (a) , (B) shows those with different load point distances. In the fretting fatigue test apparatus of one embodiment of the present invention, each item of “repetitive displacement”, “pressing force acting on the test piece from the contact piece”, and “relative slip amount between the contact piece and the test piece” Is a graph showing a change according to time.

Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. The configurations of the following embodiments can be implemented with various modifications without departing from the spirit thereof.
In the following description, the side closer to the center line CL of the load-loading ring is referred to as “inner side”, and conversely, the side away from the center line CL is referred to as the outer side.
In the description of the parts constituting the fretting fatigue test apparatus, the vertical direction, the inner side, and the outer side are determined on the basis of the state in which those parts are equipped in the fretting fatigue test apparatus.
Moreover, let the side which approaches the centerline CL of the ring 5 be an inner peripheral side, and let the side away from the centerline CL be an outer peripheral side.

[1. Constitution]
A fretting fatigue test apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a schematic cross-sectional view showing a configuration of a fretting fatigue test apparatus according to an embodiment of the present invention, which is a cross-sectional view taken along a line CC in FIG.
2 is a schematic longitudinal sectional view showing the configuration of the fretting fatigue test apparatus according to one embodiment of the present invention, in which (a) is a cross-sectional view taken along line AA in FIG. 1, and (b) is in FIG. It is BB sectional drawing.
FIG. 3 is a schematic cross-sectional view for explaining the principle of the fretting fatigue test apparatus according to one embodiment of the present invention, and is a longitudinal cross-sectional view showing a main part of the fretting fatigue test apparatus.
FIG. 4 is a schematic diagram showing the relationship between various parameters in the fretting fatigue test apparatus according to an embodiment of the present invention. FIG. 4A shows the displacement δ of the contact piece and the pressing force P acting on the test piece. FIG. 5B is a diagram showing the relationship between the displacement δ of the contact piece and the relative slip amount ΔS between the test piece and the contact piece, and FIG. 5C is a graph showing the relationship between the inclination angle θ of the test piece and the test piece. The figure which shows the relationship with the pressing force P to perform, (d) is a figure which shows the relationship between inclination-angle (theta) of a test piece, and relative slip amount (DELTA) S of a test piece and a contact piece, (e) is a test piece. The figure which shows the relationship between inclination | tilt angle (theta), the pressing force P which acts on a test piece, and the rigidity of a pressing force provision ring, (f) is relative sliding of the inclination angle (theta) of a test piece, and a test piece and a contact piece. The figure which shows the relationship between quantity (DELTA) S and the rigidity of a pressing force provision ring, (g) is the load point distance L and the contact area A of a test piece and a contact piece. Diagram showing the relationship between, (h) is a diagram showing a load point distance L, and the relationship between the contact area length Ls of the contact piece and the test piece.
FIG. 5 is a schematic diagram for explaining the relationship between the load point distance, the contact range length, and the contact area according to an embodiment of the present invention, and is a front view of a main part of the fretting fatigue test apparatus. .
In addition, the hatch which shows a cross section is abbreviate | omitted in FIGS. Moreover, in FIG. 2, the cover part 35 of the test piece holding | maintenance part 3A is abbreviate | omitted for convenience.

  As shown in FIGS. 1 and 2, a fretting fatigue test apparatus (hereinafter also referred to as “test apparatus”) 1 according to an embodiment of the present invention includes a pair of test pieces 2A and 2B, and these test pieces 2A and 2A. Test piece holders 3A and 3B for holding 2B, contact piece 4 abutting on the test pieces 2A and 2B, and a pressing force applying ring (annular body) for pressing the test pieces 2A and 2B against the contact piece 4 from the horizontal direction. , Hereinafter referred to as “ring”) 5, pressing force applying bolts (pressing force applying members) 6 A and 6 B that pass through the ring 5, and an actuator (load applying portion) 7 that applies a load to the contact piece 4. Composed.

In the present embodiment, the ring 5 has a perfect ring shape centered on the center line CL, and is made of a metal such as carbon steel or an aluminum alloy, a resin, or the like. Although this ring 2 has a certain degree of elasticity, it is preferable to use a material having a high Young's modulus and hardly deforming.
Here, the extending direction of the center line CL of the ring 5 is defined as a first direction D1, the direction orthogonal to the first direction D1 and extending left and right toward the plane of FIG. A direction orthogonal to the two directions D2 and extending up and down toward the plane of FIG. 1 is defined as a third direction D3.
A nut 51 is fixed to each outer periphery of both ends of the ring 5 in the second direction D2, and a screw hole 51b is formed so as to be connected to the screw hole 51a of the nut 51.

  The screw holes 51a and 51b are respectively provided with pressing force application bolts 6A and 6B (hereinafter referred to as pressing force application bolts 6 when the pressing force application bolts 6A and 6B are not distinguished from each other). Screwed in a posture along D2. An operating portion 61 is provided at the rear end portion of the pressing force applying bolt 6 positioned outside the ring 5 of the pressing force applying bolt 6, and the operating portion 61 is manually operated to rotate the pressing portion 61. The tip 62 of the pressure applying bolt 6 is centered on the center line CL (and test piece holding portions 3A, 3B, test pieces 2A, 2B and contact pieces 4 described later disposed closer to the center line CL than the pressing force applying bolt 6). Can be advanced or retreated. Further, the tip end portion 62 of the pressing force applying bolt 6 is constituted by a spherical tip portion (hereinafter, also referred to as “spherical tip portion 62”). The spherical tip 62 is pressed by a recess 32b provided on the outer periphery of test piece holders 3A and 3B, which will be described later, and the tip is inserted.

The test pieces 2A and 2B are arranged closer to the center line CL than the pressing force application bolts 6A and 6B so as to be sandwiched between the pressing force application bolts 6A and 6B. Further, the test pieces 2A and 2B come into contact with the contact piece 4 from the second direction D2. The test pieces 2A and 2B have the same shape, and are arranged symmetrically with respect to the center line CL and along the second direction D2. Hereinafter, when the test pieces 2A and 2B are not distinguished, they are referred to as the test piece 2.
The test piece 2 includes a test piece main body 20 and a fixing portion 21 formed integrally with the upper portion of the test piece main body 20. The test piece main body 20 has a shape in which the lower half of a rectangular plate-like body is cut obliquely outward and downward, and has an inclined surface (contact surface) 20a facing downward. Each test piece 2 is arranged with the inclined surface 20a facing the center line CL. The fixed portion 21 has a U-shaped horizontal cross section, and includes a base portion 21a whose front faces the center line CL, and side wall portions 21b and 21b extending from both ends of the base portion 21a toward the center line CL. .

As shown in FIGS. 1 and 2, the test piece holding portions 3A and 3B have the same shape, and are arranged symmetrically with respect to the center line CL and along the second direction D2. Hereinafter, when the test piece holding portions 3A and 3B are not distinguished, they are referred to as the test piece holding portion 3.
The test piece holding part 3 includes a holding part main body 31, a hanging part 32 that hangs vertically downward from the outer peripheral end of the holding part main body 31 in the second direction D2, and a thin plate that extends vertically upward from the upper part of the holding part main body 31. The suspension part 33 of the shape, the block-shaped fixing | fixed part 34 to which the upper end of the suspension part 33 was connected, and the cover part 35 attached to the centerline CL side of the holding | maintenance part main body 31 are provided.
The holding part main body 31, the hanging part 32, the hanging part 33, and the fixing part 34 are integrally formed. Each fixing portion 34 is fixed to a support portion 81 that hangs down from the support body 8 (for example, an apparatus frame).

  The holding part main body 31 is provided with a recess 31a that faces the center line CL and extends downward. The fixing portion 21 of the test piece 2 is inserted into the recess 31a. In addition, bolts 36 (indicated by the alternate long and short dash lines in FIGS. 1 and 2B) are screwed onto the side walls 31b and 31b of the holding unit main body 31, respectively. Further, the holding part main body 31 is provided with a lid part 35 so as to sandwich the test piece 2. The lid portion 35 is removed from the holding portion main body 31 by a bolt (not shown).

Each of the bolts 36 is tightened to clamp the fixing portion 21 of the test piece 2 inserted into the recess 31a, and a bolt 35 (not shown) is tightened to attach the lid portion 35 to the holding portion main body 31. The test piece 2 can be accommodated and held in the recess 31 a of the holding portion main body 31 by the main body 31. Further, the bolt 36 is loosened to separate the bolt tip from the fixing portion 21 of the test piece 2, and the bolt 35 (not shown) is loosened to remove the lid portion 35 from the holding portion main body 31, thereby removing the test piece 2 from the holding portion main body 31. Can be removed from.
A plurality of spherical concave portions 32b are arranged in parallel along the vertical vertical direction on the outer surface (outer peripheral portion, outer surface in the second direction D2) 32a of the hanging portion 32. The ring 5 is supported by the test piece holding portions 3A and 3B by inserting the tips of the spherical tip portions 62 of the pressing force applying bolts 6 into the concave portions 32b and 32b of the test piece holding portions 3A and 3B having the same height. In addition, a pressing force (surface pressure) can be applied from the ring 5 to the test pieces 2A and 2B and the contact piece 4 via the respective pressing force application bolts 6 and the test piece holding portions 3A and 3B.
That is, the ring 5 and the pressing force application bolts 6A and 6B constitute the pressing force application mechanism of the present invention.
In addition, by selecting an arbitrary height from the plurality of recesses 32b arranged in the vertical direction and inserting the tip of the spherical tip 62 of each pressing force applying bolt 6, each pressing force applying bolt 6 It is possible to adjust the height (position) of the pressing force applied from.
That is, the pressing position adjusting mechanism of the present invention is configured by the pressing force applying bolts 6A and 6B and the plurality of recesses 32b.

  The contact piece 4 is arranged so that its center line coincides with the center line CL of the ring 5 and is sandwiched between the test pieces 2A and 2B from both sides in the second direction D2. The contact piece 4 has such a shape that upper corners on both sides (that is, the contact piece 4 side) of the rectangular parallelepiped in the second direction D2 are cut obliquely outward and downward, and an inclined surface (contact surface) facing upward. 4a and 4b. The inclined surface 4a is set to the same inclination angle as the inclined surface 20a of the test piece 2A, and similarly, the inclined surface 4b is set to the same inclination angle as the inclined surface 20a of the test piece 2B. The inclined surface 4a and the inclined surface 20a of the test piece 2A are in contact with each other, and the inclined surface 4a and the inclined surface 20a of the test piece 2A can slide relative to each other. Similarly, the inclined surface 4b and the inclined surface 20a of the test piece 2B are in contact with each other, and the inclined surface 4b and the inclined surface 20a of the test piece 2B can slide relative to each other.

  As shown in FIG. 2, the actuator 7 includes a rod 71 that is attached to the upper end of the contact piece 4 and extends in the vertical direction, and an actuator body 70 that moves the rod 71 forward and backward in the first direction D1 on the center line CL. ing.

The actuator body 70 moves the rod 71 and the contact piece 4 forward and backward with respect to the test piece 2 to simultaneously apply a load repeatedly to the pair of test pieces 2 in the direction approaching or separating from the first direction D1.
Note that “inclination” of the inclined surface 20a of the test piece 2A and the inclined surfaces 4a and 4b of the contact piece 4 means that the contact piece 4 is inclined with respect to the advancing / retreating direction, that is, the first direction D1.

  With such a configuration of the test apparatus 1, as shown in FIG. 3, when a load (displacement δ) that moves upward along the first direction D1 is applied to the contact piece 4 by the actuator 7, Between the inclined surfaces 20 a and 20 a of the test piece 2 and the inclined surfaces 4 a and 4 b of the contact piece 4, a relative slip occurs between the pressing force (surface pressure) P pressing the test piece 2 and the test piece 2. A sliding force acts. That is, the load applied to the contact piece 4 from the actuator 7 follows the pressing force acting perpendicularly to the inclined surfaces 20a and 20a and the inclined surfaces 4a and 4b, and the inclined surfaces 20a and 20a and the inclined surfaces 4a and 4b. It is broken down into two component forces, sliding force acting in the direction.

  Therefore, when the displacement δ is applied to the contact piece 4, as shown in FIGS. 4A and 4B, the pressing force P varies in proportion to the magnitude of the displacement δ and the relative slip amount. ΔS varies.

  If the load (displacement δ) applied from the actuator 7 is the same, as shown in FIGS. 4C and 4D, the inclination angle θ of the inclined surface 20a of the test piece 2 (in other words, the contact piece). 4 (the inclination angle of the inclined surfaces 4a and 4b) increases (that is, as the inclined surfaces 20a, 4a and 4b approach the horizontal direction), the pressing force P increases, and the test piece 2 is pushed up by the contact piece 4 and moves upward. Since the amount of movement (the amount of movement integrally with the contact piece 4) increases, the relative slip amount ΔS between the test piece 2 and the contact piece 4 decreases.

  If the load (displacement δ) applied from the actuator 7 is the same and the inclination angle θ is the same, the higher the rigidity of the ring 5, the more the test piece 2 is removed by the ring 5 via the pressing force application bolt 6. Movement toward the direction is strongly restrained. For this reason, as shown in FIG. 4 (e), the higher the rigidity of the ring 5, the proportionally larger the pressing force P acting on the test piece 2 as the reaction force of the restraining force of the ring 5. Conversely, as shown in FIG. 4 (f), the higher the rigidity of the ring 5, the more strongly the test piece 2 is restrained by the ring 5 from moving outward. 4 increases the amount of movement upward (the amount of movement integrally with the contact piece 4), so that the relative slip amount ΔS between the test piece 2 and the contact piece 4 decreases.

Here, the contact range length Ls (hereinafter referred to as “contact length”) Ls and the contact area As between the test piece 2 and the contact piece 4 shown in FIGS. 5A and 5B will be described. Hereinafter, the contact state between the inclined surface 20a of the test piece 2 and the inclined surface 4b of the contact piece 4 will be described as an example, but the contact state between the inclined surface 20a of the test piece 2 and the inclined surface 4b of the contact piece 4 will be described. Is the same.
A major feature of the present invention is that the length of the contact range between the inclined surface 20a and the inclined surface 4b (hereinafter referred to as “contact length”) Ls, and hence the contact area As between the inclined surface 20a and the inclined surface 4b can be adjusted. ing.

Specifically, as shown in FIG. 2A, the mounting height L of the ring 5 and the pressing force applying bolt 6 with respect to the test piece holding portion 3, in other words, from the pressing force applying bolt 6 through the test piece holding portion 3. The contact length Ls and the contact area As can be adjusted by changing the input height L of the pressing force P input to the test piece 2. Here, the input height L is a distance based on the upper end of the test piece main body 20, and is hereinafter referred to as a load point distance L.
As described above, the ring 5 holds the test piece by fitting the spherical tip 62 of the pressing force applying bolt 6 into the recess 32b formed in the test piece holding part 3 (the outer surface 32a of the hanging part 32). A plurality of concave portions 32 b fixed to the portion 3 are arranged in the vertical direction on the test piece holding portion 3. By changing the concave portion 32 b to which the pressing force applying bolt 6 is attached, the ring 5 and the pressing portion for the test piece holding portion 3 are changed. The mounting height of the pressure applying bolt 6 can be changed.

This will be described with reference to FIGS. 5 (a) and 5 (b) again. 5A and 5B, the inclined surface 20a and the inclined surface 4b are in contact with each other at the contact length Ls between the contact root portion X1 and the contact tip portion X2 and the corresponding contact area As. 5 (a) and 5 (b) indicate that a contact pressure of a predetermined pressure or more is generated between the inclined surface 20a and the inclined surface 4b.
In FIG. 5A, the load point distance L (see FIG. 2A) is relatively short. In other words, the moment arm is relatively short, and therefore the moment acting on the inclined surface 20a is small. As a result, since the input of the pressing force P equal to or higher than the predetermined pressure is limited to the vicinity of the contact root portion X1, the contact tip portion X2 is relatively close to the contact root portion X1, and the contact length Ls and the contact area As ( In other words, the contact range is a relatively narrow range. In other words, the inclined surface 20a and the inclined surface 4b are in a single-contact state (non-uniform contact state) in which a strong contact pressure acts locally.

On the other hand, in FIG. 5B, since the load point distance L is relatively long, in other words, since the moment arm is relatively long, the moment acting on the inclined surface 20a is large. As a result, the input of the pressing force P equal to or higher than the predetermined pressure reaches a position relatively far from the contact root portion X1, so that the contact tip portion X2 is also relatively away from the contact root portion X1. The contact length Ls and the contact area As are in a relatively wide range.
Therefore, as shown in FIGS. 4G and 4H, as the load point distance L increases, the contact area As increases and the contact length Ls increases.
The tilt angle of the tilted surface 20a and the tilt angle of the tilted surface 4b usually do not match completely because of manufacturing errors. For this reason, the contact between the inclined surface 20a and the inclined surface 4b is not strictly the entire surface contact (uniform contact). However, by increasing the load point distance L, the contact between the inclined surface 20a and the inclined surface 4b can be brought close to the entire surface.

[2. Test procedure]
Next, the test procedure of the present embodiment will be described with reference to FIGS.
FIG. 6 is a diagram showing a fretting fatigue test apparatus according to an embodiment of the present invention. In the fretting fatigue test apparatus, “repetitive displacement δ”, “pressing force P acting from the contact piece to the test piece”, and “between the contact piece and the test piece” It is a graph which shows the change according to time T regarding each item of "relative slip amount (DELTA) S."
First, the contact piece 4 is attached to the rod 71 of the actuator 7, and the test piece 2 is attached to each test piece holding portion 3 with the inclined surface 20 a directed toward the center line CL. Further, by inserting the tips of the spherical tip portions 62 of the pressing force applying bolts 6 into the concave portions 32b and 32b of the same height of the test piece holding portions 3A and 3B, the ring 5 is connected to the test piece holding portions 3A and 3B. And a pressing force (surface pressure) is applied from the ring 5 to the test pieces 2A, 2B and the contact piece 4 via the pressing force applying bolts 6 and the test piece holding portions 3A, 3B.

Next, the actuator 7 is operated so that the inclined surfaces 4a and 4b of the contact piece 4 are in contact with the inclined surface 20a of each test piece 2, and the contact piece 4 is repeatedly displaced in the first direction D1. The fretting fatigue test is performed by applying a repeated load to the test piece 2.
When the displacement δ is applied to the contact piece 4 so as to move upward along the first direction D1, the test piece 2 is brought into contact with the contact piece 4 and the radial direction of the center line CL along the second direction D2. A relative slip occurs between the test piece 2 and the contact piece 4 due to the pressing force P that is pushed outward.
On the other hand, when the displacement δ is applied so that the contact piece 4 moves downward along the first direction D1, the elastic force of the ring 5 acts on the test piece 2 via the pressing force application bolt 6. Thus, a pressing force P that is pushed back inward in the radial direction of the center line CL along the second direction D2 is received. The pressing force P causes a relative slip between the test piece 2 and the contact piece 4.

  Such an operation is repeated by applying the up and down repeated displacement δ to the contact piece 4 by the actuator 7. That is, as shown in FIG. 6, the pressing force (surface pressure) P and the relative slip amount ΔS change in the same cycle so as to synchronize with the up and down displacement δ.

[3. Action / Effect]
In one embodiment of the present invention, a load is repeatedly applied to the contact piece 4 by the actuator 7 in the first direction D1, and the test piece 2 contacts the contact piece 4 from the direction D2 intersecting the first direction D1. The contact piece 4 and the test piece 2 can be slid relative to each other in the inclined direction of the inclined surfaces 20a, 4a, 4b. Further, the test piece 2 is elastically constrained from the ring 5, and the test piece 2 includes A pressing force P is applied from the ring 5 via the pressing force applying bolt 6 from a pressing position that is a predetermined distance (load point distance) L away from the upper end of the piece body 20.
With such a configuration, a load is repeatedly applied to the contact piece 4 in the first direction D1 by the actuator 7, so that the pressing force P to the test piece 2 is changed while the contact piece 4 and the test piece 2 are relatively moved. A fretting fatigue test can be performed with slipping.
Furthermore, the degree of contact between the contact piece 4 and the test piece 2 can be appropriately changed by changing the position of the pressing force applying bolt 6 (in other words, the load point distance L).
Therefore, the contact force between the contact piece 4 and the test piece 2 depends on the actual situation according to the actual situation (for example, per piece or per whole surface), and the pressing force (surface pressure) P is also changed. The fretting fatigue test can be performed.

  Further, since the tip of the spherical tip 62 of the pressing force applying bolt 6 is inserted into the recess 32b of the test piece holding part 3, the pressing force applying bolt 6 and the ring 5 are firmly fixed to the test piece holding part 3. become. Thereby, it can prevent that the position of the pressing force provision volt | bolt 6 and the ring 5 shift | deviates with respect to the test piece 2 or the contact piece 4 during a test, and it can test on the conditions as planned.

  Since the test pieces 2A and 2B are respectively arranged on both sides of the contact piece 4, the contact piece 4 can simultaneously apply a repeated load to the two test pieces 2A and 2B, and two test pieces can be obtained in one test. Tests can be performed on 2A and 2B.

  Furthermore, changing the material and diameter of the ring 5 to adjust its rigidity, changing the material, shape and dimensions of the specimen holder 3 to adjust its rigidity, and the inclination angle of the specimen 2 By adjusting θ, when a load is repeatedly applied from the actuator 7 to the contact piece 4, the pressing force P acting on the contact piece 4 and the test piece 2, and the relative slip between the contact piece 4 and the test piece 2. The amount ΔS can be changed.

[4. Others]
(1) In the above-described embodiment, the annular body of the present invention is configured by the perfect circle ring 5, but the annular body is not limited to a perfect circle, and may be an angular ring shape or an oval shape. Alternatively, a pair of rod-shaped bodies are arranged in parallel with a gap, and each end (or the vicinity of each end) of the rod-shaped body is connected by a biasing member (for example, a spring) to form an annular body. The test piece 2 may be pressed against the contact piece 4 via the test piece holding part 3 by this rod-shaped body.

  (2) In the above embodiment, the pressing force applying bolt 6 screwed into the ring 5 is the pressing force applying member of the present invention, but the pressing force applying member is not limited to this configuration. For example, as a pressing force applying member, a rod-shaped member may be attached to the annular body in a state of being biased by the biasing means toward the test piece holding part 3 and the test piece 2, or simply fixed to the ring 5. Good.

  (3) In the above-described embodiment, the test piece 2 is pressed by the pressing force applying bolt 6 via the test piece holding portion 3, but the pressing force applying bolt 6 is brought into contact with the test piece 2 to press the pressing force. A pressing force may be directly applied from the applying bolt 6 to the test piece 2. As such a configuration, with respect to the test apparatus 1 of the embodiment shown in FIGS. 1 and 2, the hanging portion 32 b of the test piece holding portion 3 positioned between the pressing force applying bolt 6 and the test piece main body 20 is provided. A configuration to be omitted is illustrated.

  (4) In the above embodiment, the pressing force application bolt 6 is integrated with the ring 5, and the mounting position with respect to the test piece holding part 3 and the test piece 2 is changed, so that the pressing position (pressing force is applied to the test piece 2). However, the pressing position with respect to the test piece 2 may be changed by changing the mounting position of the pressing force applying bolt 6 to the ring 5.

(5) In the above embodiment, the inclined surfaces 20a of the test pieces 2A and 2B are set to the same angle and the inclined surfaces 4a and 4b of the contact piece 4 are set to the same angle, but the test pieces 2A and 2B are inclined. The surface 20a may be different from each other, and the angles of the inclined surfaces 4a and 4b of the contact piece 4 may be different from each other as an angle corresponding to the angle of the inclined surface 20a of the test pieces 2A and 2B.
If the test pieces 2A and 2B and the contact piece 4 are capable of sliding contact, the inclined surface 20a of the test piece 2A and the inclined surface 4a of the contact piece 4 may not be at the same angle. The inclined surface 20a and the inclined surface 4b of the contact piece 4 need not have the same angle.

DESCRIPTION OF SYMBOLS 1 Fretting fatigue test apparatus 2A, 2B Test piece 20 Test piece main body 20a Inclined surface (contact surface)
21 Fixing part 21a Base part 21b Side wall part 3A, 3B Specimen holding part 31 Holding part main body 31a Recess 31b Side wall 32 Hanging part 32a Outside surface (outer peripheral part) of hanging part 32
32b Concave part 33 Hanging part 34 Fixing part 35 Lid part 36 Bolt 4 Contact piece 4a, 4b Inclined surface (contact surface)
5 Pressing Force Applying Ring 51 Nut 51a Screw Hole 51b of Nut 51 Screw Holes Formed in the Pressing Force Applying Ring 6, 6A, 6B Pressing Force Applying Bolt (Pressing Force Applying Member)
61 Operation section 62 Tip (spherical tip)
7 Actuator (load application part)
70 Actuator body 71 Rod 8 Support body 81 Support part As Contact area CL Center line of pressing force applying ring D1 First direction D2 Second direction D3 Third direction L Load point distance Ls Contact range length P Pressing acting on test piece Force X1 Contact root X2 Contact tip ΔS Relative slip amount between test piece 2 and contact piece 4 δ Displacement of contact piece 4 θ Inclination angle of test piece 2

Claims (7)

A contact piece;
A load applying portion for applying a load repeatedly in the first direction to the contact piece;
A test piece that comes into contact with the contact piece from a second direction intersecting the first direction,
A pressing force application mechanism that applies a pressing force at a predetermined pressing position to the contact piece and the test piece by elastically restraining the contact piece and the test piece from the second direction;
A pressing position adjusting mechanism for adjusting the pressing position of the pressing force applying mechanism with respect to the first direction;
The fretting fatigue testing apparatus, wherein a contact surface between the contact piece and the test piece is set to have a shape inclined with respect to the first direction.   2. The fretting fatigue testing apparatus according to claim 1, wherein a pair of the test pieces are provided on both sides of the contact piece so as to contact the contact piece from both sides in the second direction. The pressing force application mechanism is
An annular body arranged so as to surround the test piece from the outside in the second direction;
The fretting fatigue according to claim 2, further comprising: a pressing force applying member that is attached to the annular body and applies a pressing force directly or indirectly to the test pieces. Test equipment. The fretting fatigue test apparatus according to claim 3, wherein the pressing force application member is attached to the annular body in a pair toward the pair of test pieces. It is arranged on the inner peripheral side of the annular body, and includes a test piece holding part that holds the test piece,
The test piece holding part includes an outer peripheral part arranged on the outer peripheral side of the held test piece,
Each of the pair of pressing force applying members presses the test piece against the contact piece via the outer peripheral portion by bringing the tips into contact with the outer peripheral portion at an arbitrary position in the first direction. Fixed to the outer periphery,
The fretting fatigue test apparatus according to claim 4, wherein the pressing position adjusting mechanism includes the pair of pressing force applying members. The outer peripheral portion of the test piece holding portion is provided with a plurality of concave portions into which the tip of the pressing force applying member is inserted along the first direction,
6. The fretting fatigue testing apparatus according to claim 5, wherein the pressing position adjusting mechanism includes the pair of pressing force applying members and the plurality of recesses.   Using the fretting fatigue test apparatus according to any one of claims 1 to 6, the pressing position of the pressing force application mechanism is adjusted with respect to the first direction, and the contact piece and the test are adjusted. A fretting fatigue test method in which a fretting fatigue test is performed while a piece is in a contact state or a full contact state.

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