JP3849331B2 - Material testing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a material testing machine including an axis adjusting device for a gripping member that grips a specimen.
[0002]
[Prior art]
Conventionally, for example, as shown in FIG. 7, a pair of support columns 3 are erected on a base 1, and a specimen 4 is installed in a load frame that is formed by cross-crossing a crosshead 2 there. A material testing machine is known in which a load and a displacement are measured by a load cell 6 and a displacement detector 7 such as a differential transformer while applying a load to the specimen 4 to obtain a load-displacement characteristic of the specimen 4. At this time, the specimen 4 is gripped by the upper and lower grips 8 and 9, but an accurate test cannot be performed unless the axes of the grips 8 and 9 are aligned. Therefore, conventionally, the grip 8 is attached to the crosshead 2 via a spherical bearing as disclosed in Japanese Patent Laid-Open No. 2-203241 or the inclined plates 10 and 11 as shown in FIG. Can be adjusted so that its axis is vertical (direction of load action).
[0003]
As shown in the perspective view of FIG. 8B, holes 10a and 11a are formed at the centers of the inclined plates 10 and 11, respectively. The grip 8 is attached to the cross head 2 so that the inclined plates 10 and 11 are sandwiched between the cross head 2 and the grip 8. At this time, the mounting shaft 8 a of the grip 8 passes through the holes 10 a and 11 a of the inclined plates 10 and 11 and is screwed to the mounting plate 12. The jack plate 13 is used to attach the mounting plate 12 to the crosshead 2. By pulling upward, the grip 8 is fastened to the crosshead 2 with a predetermined force.
[0004]
J1 in FIG. 8B indicates the normal line of the surface 10b of the inclined plate 10, and when the inclined plate 10 is rotated with respect to the vertical axis z, the normal line J1 of the surface 10b rotates around the Z coordinate axis as shown in the figure. To do. On the other hand, as shown in FIG. 8 (c), when the inclined plate 11 is rotated while maintaining the contact between the inclined surface 11b of the inclined plate 11 and the inclined surface 10b of the inclined plate 10, the inclined plate 11 rotates the normal line J1 along the rotation axis. Rotate as Therefore, the normal line J2 of the surface 11c to which the grip 8 is fixed rotates around the normal line J1. That is, the tilt plate 10 is turned to change the direction of the shaft core, and the tilt plate 11 is turned to adjust the tilt of the shaft core.
[0005]
[Problems to be solved by the invention]
By the way, when the tilt adjustment is performed, the jack bolts 13 are once loosened, the rotation angles of the respective inclined plates 10 and 11 are adjusted, and the jack bolts 13 are tightened and fixed again. However, when the jack bolt 13 is tightened again, the rotation angle of the inclined plates 10 and 11 may be shifted from the set position, and there is a drawback that it takes time for adjustment. Moreover, when the position of inclined board 10 and 11 itself has shifted | deviated, it is necessary to move the attachment position of the inclined boards 10 and 11 whole. On the other hand, when adjustment is performed using a spherical bearing, there is a disadvantage that the apparatus is expensive because spherical processing of the bearing is difficult.
[0006]
An object of the present invention is to provide a material testing machine including an axis adjustment device that can easily adjust the axis of a gripping member at a relatively low cost.
[0007]
[Means for Solving the Problems]
The embodiment of the invention will be described with reference to FIGS. 1, 2, and 5.
(1) The invention of claim 1 is applied to a material testing machine including an axis adjustment device 20 that adjusts the axis of a gripping member 8 that is fixed to the load frame 2 and holds the specimen 4. The device 20 has a first arc surface 211a, a first member 201a whose relative position to the load frame 2 is constant, and a second arc surface 211b, and a second member to which the gripping member 8 is fixed. A third arc surface 212 that contacts the first arc surface 211a and the fourth arc surface 213 that contacts the member 201b and the second arc surface 211b. The first angle adjusting member 203a that adjusts the rotation angle of the third member 202 relative to the first member 201a with the center axis J6 of the cylindrical curved surface including the member 202 and the first circular arc surface 211a as the rotation axis. 203b and a cylindrical curved surface including the second arcuate surface 211b The second angle adjusting members 205a and 205b for adjusting the rotation angle of the second member 201b with respect to the third member 202 with the central axis J7 as the rotation axis, and the positions of the third member 202 with respect to the load frame 2 The first position adjusting members 204a and 204b that adjust in one direction (Y coordinate axis direction), and the second direction (X coordinate direction) where the position of the second member 201b relative to the third member 202 differs from the first direction And the second position adjusting members 206a and 206b for adjusting the above-mentioned object.
[0008]
In the section of the means for solving the above-described problems for explaining the configuration of the present invention, the drawings of the embodiments of the invention are used for easy understanding of the present invention. The form is not limited.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing an embodiment of a material testing machine according to the present invention, and is a diagram showing a schematic configuration of a testing machine main body. In FIG. 1, the same parts as those in FIGS. 7 and 8 are denoted by the same reference numerals, and different parts will be mainly described. In FIG. 1, the grip 8 is attached to the crosshead 2 via an axis adjusting device 20. In FIG. 1, the load cell is omitted.
[0010]
2A and 2B are diagrams showing details of the shaft center adjusting device 20, wherein FIG. 2A is a cross-sectional view seen from the front of FIG. 1, and FIG. 2B is a cross-sectional view taken along line AA ′ of FIG. FIG. 3 is a plan view of the axis adjusting device 20 viewed from the crosshead 2 side. The shaft center adjusting device 20 includes a body 202 and a pair of collars 201a and 201b arranged so as to sandwich the body 202 from above and below, and the shaft core of the collar 201a is adjusted using bolts 203a, 203b, 204a and 204b. The axis of the collar 201b is adjusted using bolts 205a, 205b, 206a, and 206b.
[0011]
When the grip 8 is attached to the crosshead 2, the collar 201b, the body 202 and the collar 201a are inserted so that the rod 21 provided on the grip 8 penetrates the holes 201 and 202 formed in the collars 201a and 201b and the body 202. The mounting plate 22 is attached to the tip portion of the rod 21 between the cross head 2 and the rod 21. The grip 8 is jacked up with a predetermined force by the jack bolt 23 and fixed to the cross head 2.
[0012]
FIG. 4 is a perspective view of the collar 201a. The collar 201a is a columnar member in which one of the side surfaces of a prism is formed on a convex arcuate surface 211a having a radius of curvature R. In the case of the collar 201a, the arcuate surface 211a is directed downward. Is arranged. The collar 201b has the same shape as the collar 201a. In the case of the collar 201b, the collar 201b is disposed with the arc surface 211b facing upward. Reference numerals 201b and 211b relating to the collar 201b are shown in parentheses. Here, when the direction of the arrow in FIG. 4 is named the longitudinal direction of the collar, as shown in FIG. 2, the longitudinal direction of the collar 201a and the longitudinal direction of the collar 201b are arranged so as to be orthogonal to each other. That is, the longitudinal direction of the collar 201a is parallel to the Y coordinate axis, and the longitudinal direction of the collar 201b is parallel to the X coordinate axis. A curved surface indicated by a one-dot chain line 220 in FIG. 4 represents a cylindrical curved surface having a radius R including the circular arc surface 211a (211b).
[0013]
As shown in the plan view of FIG. 3, with respect to the collar 201a, tilt adjusting bolts 203a and 203b are provided in the X coordinate axis direction, and Y direction position adjusting bolts 204a and 204b are provided in the Y coordinate axis direction. For example, when adjusting (moving) the body 202 in the positive direction of the Y coordinate, the bolt 204a is loosened and the bolt 204b is tightened. Conversely, when adjusting in the minus direction, the bolt 204b is loosened and the bolt 204a is tightened. The axis inclination adjustment will be described later. On the other hand, as can be seen from FIG. 2, with respect to the collar 201b arranged so as to be orthogonal to the collar 201a, tilt adjusting bolts 205a and 205b are provided in the Y coordinate axis direction, and for adjusting the X direction position in the X coordinate axis direction. Bolts 206a and 206b are provided.
[0014]
As shown in FIG. 2, the shape of the surface 212 of the body 202 that contacts the arc surface 211a of the collar 201a forms a concave arc surface having the same radius of curvature R as the arc surface 211a, and the arc surface 211b of the collar 201b. The surface 213 in contact with the circular arc surface 212 forms a concave arc surface similar to that of the circular arc surface 212, although the direction is different by 90 degrees. In FIG. 2 and FIG. 5 to be described later, in order to make the drawing easier to see, the arc surfaces 211a and 211b are shown to have a gap between the arc surface 212 and the arc surface 213, but actually they are in contact. At least one surface of the contact surfaces (211a, 211b, 212, 213) has a low coefficient of friction material (for example, polytetrafluoroethylene (PTFE) or the like) for the purpose of reducing the frictional force of the contact portion when adjusting the axis. Coated with molybdenum disulfide. This coating is preferably applied on both sides of the contact surface. In addition, it is preferable to perform the same coating on the surface where the adjustment bolts 203a, 203b, 204a, 204b, 205a, 205b, 206a, and 206b contact.
[0015]
FIGS. 5A and 5B are diagrams for explaining the axis tilt adjustment by the axis adjusting device 20, wherein FIG. 5A shows the tilt adjustment in the X coordinate axis direction, and FIG. 5B shows the tilt adjustment in the Y coordinate axis direction. As shown in FIG. 5A, when the upper grip 8 is tilted in the negative direction of the X coordinate axis (angle θ1), the bolt 203a is loosened and the bolt 203b is tightened to bring the body 202 into the axis J6 (perpendicular to the paper surface). The shaft 8 is rotated counterclockwise about the rotation axis, and is tilted by an angle θ1 in the positive X-coordinate direction (right side in the drawing) so that the shaft core J4 of the grip 8 coincides with the shaft core J5 of the grip 9 (see FIG. 1). The axis J6 is the central axis of the cylindrical curved surface (the cylindrical curved surface 220 shown in FIG. 4 and the circular arc surface 212 is also included in this cylindrical curved surface) including the circular arc surface 211a. Although not shown, conversely, when the grip 8 is tilted in the positive direction of the X coordinate axis, the bolt 203b is loosened and the bolt 203a is tightened to tilt the body 202 in the negative X coordinate direction.
[0016]
On the other hand, as shown in FIG. 5B, when the grip 8 is inclined in the negative direction of the Y-coordinate axis (angle θ2), the bolt 203a related to the collar 201b is loosened and the bolt 203b is tightened to hold the collar 201b to the grip 8 Rotate counterclockwise with the axis J7 (axis perpendicular to the paper surface) as the rotation axis with respect to the body 202, and tilt the angle Y2 in the positive Y coordinate direction (right side in the figure) to grip the axis J4 of the grip 8. It is made to correspond to the axial center J5 of 9. Conversely, when the grip 8 is inclined in the positive direction of the Y coordinate axis, the bolt 203b is loosened and the bolt 203a is tightened to incline the collar 201b in the negative Y coordinate direction. The axis J7 is a central axis of a cylindrical curved surface including the arc surface 211b of the collar 201b.
[0017]
In addition, the axial center adjustment mentioned above performs an evaluation test using the test piece 70 for evaluation which provided the some strain gauge G in the side surface of a cylindrical member, as shown in FIG. In this case, the adjustment bolts 203a, 203b, 204a, 204b, 203a, 203b, 204a, and 204b are adjusted so that the strain of the strain gauge 70 when gripping both ends of the test piece 70 and applying a tensile load becomes zero. adjust. For example, the adjustment angle is adjusted to 0.1 ° or less and the lateral (X and Y coordinate directions) shift is 1 mm or less. Such an axis adjustment is performed at the time of shipment of the material testing machine, when the grips 8 and 9 are replaced, or every time the test piece is converted.
[0018]
In the embodiment described above, the collar 201a and the arc surface 211 having the same radius of curvature are formed on the collar 201a. However, it is not always necessary to use the arc shape having the same shape, and further, a concave arc instead of a convex arc surface. It is good as a surface. In the case of a concave arc surface, the curved surfaces 212 and 213 of the body 202 are convex arc surfaces. Further, although the collars 201a and 201a are disposed so as to be orthogonal to each other, they may not be strictly orthogonal.
[0019]
As described above, in the present embodiment, by adjusting the bolts 203a, 203b, 205a, and 205b, the inclination of the grip 8 fixed to the collar 201b can be adjusted in two directions, and the bolts 204a and 204b can be adjusted. , 206a, 206b, the grip 8 can be adjusted in the X coordinate direction and the Y coordinate direction. These adjustments can be performed with the grip 8 being jacked up, and accurate axis adjustment can be easily performed. In addition, since the formation of the arc surfaces 211a, 211b, 212, and 213 is easier than the formation of the spherical surface of the spherical bearing, an increase in manufacturing cost can be suppressed.
[0020]
In the correspondence between the embodiment described above and the claims, the crosshead 2 is a load frame, the grip 8 is a gripping member, the arc surface 211a is a first arc surface, and the arc surface 211b is a second arc. The arc surface 212 is the third arc surface, the arc surface 213 is the fourth arc surface, the collar 201a is the first member, the collar 201b is the second member, and the body 202 is the third member. The bolts 203a and 203b are first angle adjusting members, the bolts 205a and 205b are second angle adjusting members, the bolts 204a and 204b are first position adjusting members, and the bolts 206a and 206b are second positions. Each adjustment member is configured.
[0021]
【The invention's effect】
As described above, according to the first aspect of the present invention, the second member to which the holding member for holding the specimen is fixed can be rotated with respect to the third member, and the third member is loaded. Since the first member having a fixed relative position to the frame is rotatable, the rotation angle of the second member and the third member can be adjusted by the first and second angle adjusting members. Can be easily adjusted in two directions. In addition, since the contact surfaces of the first to third members are arcuate surfaces, the manufacturing cost can be reduced as compared with a conventional spherical bearing.
Further, by adjusting the position of the third member with respect to the load frame and adjusting the position of the second member with respect to the third member, the position of the gripping member is adjusted in two different directions. Therefore, more accurate axis adjustment is possible.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of a testing machine main body of a material testing machine according to the present invention.
2A and 2B are diagrams for explaining the details of an axis adjusting device 20; FIG. 2A is a cross-sectional view along the X coordinate axis, and FIG. 2B is a cross-sectional view along AA ′ in FIG.
FIG. 3 is a plan view of the shaft center adjusting device 20 as viewed from the crosshead 2 side.
FIG. 4 is a perspective view of a collar 201a.
FIGS. 5A and 5B are diagrams for explaining tilt adjustment by the axis adjusting device 20; FIG. 5A shows tilt adjustment in the X coordinate axis direction, and FIG. 5B shows tilt adjustment in the Y coordinate axis direction;
6 is a view showing an evaluation test piece 70. FIG.
FIG. 7 is a diagram showing an outline of a testing machine main body of a conventional material testing machine.
8A and 8B are diagrams illustrating the inclined plates 10 and 11, where FIG. 8A is a cross-sectional view of the inclined plate portion, FIG. 8B is a perspective view of the inclined plates 10 and 11, and FIG. .
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Base 2 Crosshead 3 Support | pillar 4 Specimen 8 and 9 Grip 20 Axis center adjusting device 21 Rod 22 Mounting plate 23 Jack bolt 70 Evaluation test piece 201a, 201b Color 202 Body 203a, 203b, 204a, 204b, 205a, 205b , 206a, 206b Bolt 211a, 211b, 212, 213 Arc surface

Claims (1)

In a material testing machine provided with an axis adjustment device that adjusts the axis of a gripping member fixed to a load frame and gripping a specimen,
The shaft center adjusting device has a first arc surface, and a first member having a constant relative position to the load frame;
A second member having a second arcuate surface to which the gripping member is fixed;
A third member having a third arc surface that comes into contact with the first arc surface and a fourth arc surface that comes into contact with the second arc surface;
A first angle adjusting member for adjusting a rotation angle of the third member with respect to the first member, the rotation axis being a central axis of a cylindrical curved surface including the first arc surface;
A second angle adjusting member that adjusts a rotation angle of the second member with respect to the third member, with a central axis of a cylindrical curved surface including the second arc surface as a rotation axis;
A first position adjusting member that adjusts the position of the third member with respect to the load frame in a first direction;
A material testing machine comprising: a second position adjusting member that adjusts a position of the second member with respect to the third member in a second direction different from the first direction.

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