JPH0714859Y2 - Micro indentation type material physical property tester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a bearing support mechanism in an apparatus for measuring physical properties such as mechanical properties near the surface of various solid materials. More specifically, the present invention pushes the indenter into the surface of the test material with a very small load to a very small depth, changes the load at the time of pushing and pulling out the indenter, and considers the relationship between each load and the indentation depth. A bearing supporting mechanism capable of accurately supporting an indenter arm holding the above-mentioned indenter in a test device for measuring physical properties near the surface of a test material.

[Prior Art] Several μm near the surface of a solid material in various industrial fields
It is desired to measure physical properties such as mechanical properties of the part. For example, in the field of nuclear industry, in order to understand the deterioration of the surface of the material due to radiation, the change in characteristics, etc.
It is necessary to measure the physical properties near the surface of this material. In addition to the above, such measurement is also required when measuring the physical properties of a thin synthetic resin film, or when measuring the physical properties of a coating film, paint or the like. Also in the field of the semiconductor industry, it is necessary to measure the physical properties of the thin film of the circuit pattern deposited on the surface of the chip.

Conventionally, a micro hardness meter is used to measure the physical properties near the surface of such a test material. This micro hardness tester
Although it is basically the same as the conventional hardness tester, the load applied to the indenter was set to several tens of mg, and the indentation depth of this indenter was made extremely shallow so that only the physical properties near the surface of the test material could be measured. It is a thing.

However, when the pressing depth of the indenter becomes extremely shallow as described above, the accuracy of the measured hardness is significantly reduced. That is, in the initial state where the indenter is in contact with the surface of the test material, the deformation of the surface is elastic deformation, and the indentation corresponding to the indenter becomes small, resulting in an error that the apparent hardness becomes extremely high. Surface roughness also causes such measurement error. When the indentation depth of the indenter is extremely shallow as described above, the influence of these errors becomes extremely large, and accurate measurement cannot be performed.

In order to reduce such an error, "Japanese Patent Laid-Open No. 62-69141"
, And Japanese Patent Application Laid-Open No. 62-231136. These devices reduce the error by pushing the indenter while changing the pushing load of the indenter and measuring the relationship between each load and the pushing depth continuously or stepwise. However, these materials assume that the load of the indenter and the indentation depth are substantially proportional to each other, that is, the surface of the test material is plastically deformed in response to the indentation of the indenter. Therefore, these are intended for measurements in the range of a few μm to a few tens of μm on the surface of the material.

However, recently, it has been demanded to measure the physical properties of the material near the surface with higher accuracy. To meet the demand for higher precision of such measurement, 1 μm of the surface of the material
Alternatively, it is required to measure the physical properties of only an extremely shallow portion below this. When such an extremely shallow partial indenter is pushed in, the effects of elastic deformation and surface roughness of the material become extremely large, the relationship between the load of the indenter and the indentation depth becomes complicated, and the accuracy drops significantly. Occurs.

To improve such inconvenience, push the indenter into an extremely shallow area of the test material surface while changing the load acting on the indenter, and pull out the indenter while changing the load. At, continuously measure and record the relationship between indenter load and indentation depth,
From the relationship between these loads and depths, methods have been developed to measure physical properties such as tensile strength and Young's modulus of this material.

However, in the measuring device used in such a method, the pushing load of the indenter is about several mg and the pushing depth is about 1 μm. Therefore, the conventional push-type hardness tester is not sufficient in accuracy and is not suitable for the above-described precise measurement.

Therefore, in order to carry out such a measurement, it is necessary to make the pushing load and the pushing depth of the indenter extremely small as described above. For this purpose, the indenter arm holding the above indenter can be made extremely accurate and smooth. A supporting bearing structure is required.

[Problems to be Solved by the Invention] The present invention has been made based on the above circumstances, and is a highly accurate micro-pushing type material property testing device capable of performing accurate measurement even when the indenter load and the indentation depth are extremely small. In the above, there is provided a bearing support mechanism capable of accurately and smoothly supporting the indenter arm that holds the indenter.

[Means for Solving the Problems] The present invention is to improve the bearing structure of the indenter arm that holds the indenter, thereby eliminating the play in this portion, thereby improving the accuracy. The bearing support mechanism of the present invention comprises bearings mounted on both sides of the indenter arm. Further, from the frame side, a pair of needle shafts having conical tip ends project from each other, and the tip ends of these needle shafts are fitted in the bearings to support the indenter arm. At least one of these needle shafts is urged by a spring so as to approach each other.

[Operation] According to the present invention, the needle shaft having the conical tip is fitted in the bearing by the urging force of the spring, and the needle shaft and the bearing are accurately and concentrically positioned, and the bearings are Since an axial biasing force is applied to the bearing, the play between the bearing and the needle shaft is completely removed, and the accuracy of the test apparatus is improved.

Embodiments Embodiments of the present invention will be described below with reference to the drawings. First, a measuring device equipped with the bearing support mechanism of the present invention will be described.

FIG. 1 schematically shows the entire measuring device. Reference numeral 1 in the figure is a measuring machine, which is housed in an airtight container 2. A measuring / controlling device 3 is connected to the measuring machine 1, and the measuring / controlling device 3 is arranged outside the airtight container 2. A vacuum pump 4 is connected to the airtight container 2 via an opening / closing valve 5 so that the airtight container 2 is decompressed or evacuated. Further, 6 is an open valve, and this open valve 6
The inside of the airtight container 2 can be returned to the atmospheric pressure by opening the valve. In addition, 7 is a pressure gauge, and the pressure in this airtight container 2 is displayed by this pressure gauge 7. The inside of the airtight container 2 is replaced with an inert gas as necessary to prevent the test material or the like from being oxidized.

The airtight container 2 has a container body 11 made of a transparent acrylic resin plate, and the entire surface of the container body 11 is open, and an openable door 13 is pivotally attached to this opening. There is. The door 13 is formed of a transparent acrylic resin plate and is locked in a closed state by a latch mechanism 14. Also,
Airtightness is maintained between the door 13 and the container body 11 by the seal 17. The container body 11 and the door 13 are reinforced by reinforcing ribs 15 and 16 made of a transparent acrylic resin plate. In addition, a damper leg is provided on the bottom of the container body 11.
12 is provided to block external vibration.

The measuring machine 1 is housed in the airtight container 2 as described above, and at the time of measurement, the door is closed and the air in the airtight container 2 is evacuated to a vacuum, so that there is no vibration or fluctuation of air and the measurement accuracy is improved. .

Next, the structure of the measuring machine 1 will be described with reference to FIGS. 3 and 4. The measuring machine 1 has a frame 20. A sample table 21 is provided on the frame 20. The sample table 21 is provided with a plurality of micrometer heads 22 and 23 so that a placed test material (not shown) can be accurately moved in the horizontal and vertical directions and positioned.

An indenter arm 30 is provided on the upper portion of the frame 20. The indenter arm 30 is supported by a bearing support mechanism 70 described later. The indenter arm 30 includes a horizontally extended indenter arm portion 31, a downwardly extended drive arm portion 32, and a load arm portion 33. The load arm portion 33 extends in the horizontal direction opposite to the indenter arm portion 31, and a balance weight 34 is movably attached to the tip end portion thereof. An indenter 36 is attached to the tip of the indenter arm 31 via an attachment mechanism 35. Further, micrometer type clamps 38, 39 are attached to the frame 20. By advancing these clamps 38, 39, they come into contact with the drive arm portion 32 and the load arm portion 33 of the indenter arm 30 and lock the indenter arm 30 so as not to rotate. These clamps 38 and 39 are used when calibrating the indentation depth detector 50, which will be described later.

A pushing load mechanism 40 is arranged corresponding to the tip of the drive arm portion 32. The pushing load mechanism 40 includes a solenoid 42 and a plunger 41. The solenoid 42 is attached to the frame 20 side, and the plunger 41 is attached to the drive arm portion 32 side. A current is supplied to the solenoid 42 from a load current supply device 43 shown in FIG. 5, the plunger 41 is attracted to apply torque to the indenter arm 30, and the indenter 36 corresponds to the value of the load current. It is configured to be pushed into the test material with the pushing load. The pushing load of the indenter 36 can be adjusted within the range of 1 mg to several g.

A pushing depth detector 50 is arranged above the tip of the indenter arm 31. The indentation depth detector 50 uses an optical displacement gauge, detects the displacement of the tip of the indenter arm portion 31 with an accuracy of, for example, 10 nm,
The indentation depth of this indenter is detected and converted into an electric signal.
The indentation depth detector 50 is constructed so that it can be precisely positioned vertically by a direct acting micrometer head 51.

A load detector 60 is attached to the frame side corresponding to the tip of the load arm section 33. Further, the tip of the load arm portion 33 has a protrusion 37 at a position symmetrical to the indenter 36 with respect to the bearing support mechanism 70.
Is projected. Then, the protrusion 37 contacts the contact 62 of the load detector 60. The load detector 60 is capable of detecting a load with an accuracy of mg. The load detector 60 measures the torque of the indenter arm 30 to calibrate the pushing load mechanism 40. The load detector 60 is moved by the micrometer head 61, and the contact 62 of the load detector 60 is moved when the measurement is performed.
About 1mm away from.

The details of the bearing support mechanism 70 are shown in FIG. The frame 20 is provided with supporting members 71, 72 arranged on both sides of the indenter arm 30 in a protruding manner. Further, a pair of needle shafts 73, 74 opposed to each other are provided in a protruding manner in the horizontal direction from these support members 71, 72. The tip ends of these needle shafts 73 and 74 are each formed in a conical shape. A horizontal hole is formed in the indenter arm 30, and a spacer sleeve 75 is inserted in the hole and fixed by a set screw 76. A pair of bearings 77 are fitted on both sides of the spacer sleeve 75, and the tip ends of the needle shafts 73 and 74 are fitted inside the inner races of these bearings 77. This indenter arm 30 is supported via.

The one needle shaft 73 is fixed to the one support member 71 by a set screw 83. The other needle shaft 74 is slidably supported by the other support member 72. A tubular member 84 is attached to the back side of the other support member 72, and a screw hole is formed on the inner surface of the tubular member 84.
78 are formed. In this screw hole 78, the spring 82
The spring 82 urges the needle shaft 74 to move forward, and the tip of the needle shaft 74 is urged by the urging force of the spring 82 into a bearing 77.
Is configured to fit within. Therefore, in the bearing 77 of the indenter arm 30, the tip ends of the conical needle shafts 73 and 74 are fitted from both sides by the urging force of the spring 82, and the play of the bearing portion is removed to achieve a precise and smooth movement. It is configured to support. In addition, the above screw holes
A pushing member 79 is screwed inside the 78, and the biasing force of the spring 82 can be adjusted by screwing the pushing member 79. In addition, 80 is a lock nut of this pushing member 79. Further, a rod 81 is projected from the rear end portion of the needle shaft 74, and the rod 81 is the pushing member.
It penetrates through 79 slidably. Therefore this rod
By pulling the tip of 81, the above-mentioned needle shaft 74 retracts against the urging force of the spring 82, and these needle shafts 73, 74 can be pulled out from inside the bearing 77. Etc. are configured to be easily performed.

Further, FIG. 5 shows the configuration of the measurement / control device 3 described above. A measuring / controlling circuit 90 is provided in the measuring / controlling device 3, and this circuit controls, calibrates, and processes measurement results of the measuring machine 1 as described later. The measurement / control circuit 90 sends a control signal to the load current supply device 43 described above to control the current supplied to the solenoid 42 of the pushing load mechanism 40, and applies the pressing load of the indenter 36 in a predetermined pattern. Control. The load current supplied from the load current supply device 43 is the current detector.
The signal is detected by 94, converted into a digital signal by the A / D converter 93, and then fed back to the measurement / control circuit 90. The signals from the indentation depth detector 50 and the load detector 60 are also amplified by the amplifiers 92 and 96, respectively, and converted into digital signals by the A / D converters 91 and 95, and then measured as described above. -Sent to the control circuit 90.

The measurement / control circuit 90 is also programmed to calibrate the indentation load mechanism 40 as follows. First, prior to measurement or periodically, the load detector 60 is moved downward and its contactor 62 is moved to the indenter arm.
It contacts the stem 37 of 30. When the measurement / control device 3 is operated, a control signal is output from the measurement / control circuit 90 to the load current supply device 43, and the current i supplied from the load current supply device 43 to the solenoid 42 is Sixth
As shown in the figure, it is increased stepwise by a constant Δi at every constant time Δt. By energizing this solenoid 42, torque is generated in the indenter arm 30 and the
37 presses the contact 62 of the load detector 60, and the load is detected. Since the protrusion 37 is arranged in a position symmetrical with respect to the indenter 36 and the bearing mechanism 70, the load acting on the protrusion 37 is the pushing load actually acting on the indenter 36 at the time of measurement. equal. The load w detected by the load detector 60 increases stepwise by Δw corresponding to the increase in the load current i. Then, the measurement / control circuit 90 described above performs the load current as shown in FIG. 7 at each stage.
i _{(1 ... n)} and the load w _{(1 ... n)} as shown in FIG. 8 are recorded respectively, and the relationship between these currents and the load is w = S.i + T (1) as shown in FIG. 9A. Is approximated by the formula. Note that S and T are constants.
As is apparent from FIG. 9A, the constant S is the increase in the load T, that is, the pushing load with respect to the increase in the load current i, and this S is the coil sensitivity of the solenoid 42. Thus, this S and T
By calculating the value of, the load current i corresponding to an arbitrary pushing load can be accurately determined. The above calculation is automatically performed in the measurement / control circuit 90 and is automatically stored, and the result is displayed or printed out if necessary.

Further, the measurement / control circuit 90 is programmed to automatically calibrate the indentation depth detector 50 as described below. First, prior to calibration, the clamps 38, 39 are moved forward, and the indenter arm 30 is locked so as not to rotate. Next, the amount of movement and the number of steps for each step of the indentation depth detector when calibrating the measurement / control circuit 90 are input. In addition, such a setting may be performed in advance. And the above measurement
When the control device 3 is activated, the output from the depth detector 50 is input to the measurement / control circuit 90 and recorded.
Next, the signal from the measurement / control circuit 90 gives a command to calibrate the next step. The worker
According to this command, the above-mentioned direct acting micrometer
By operating 51, the depth detector 50 is moved with respect to the indenter arm 30 by a predetermined displacement amount Δ1 set in advance. Next, the measurement / control circuit 90 receives and records the output from the depth detector 50. Depth detector
Measure the movement of 50 and its output. The relationship between the movement amount 1 and the output V thus measured is as shown in FIG. 9B. From such characteristics, the relationship between 1 and V is applied to the relational expression of V = k · 1 + M (2) to calculate the constant k. This constant k is the slope of the straight line shown in FIG. 9B, that is, the sensitivity of the indentation depth detector 50. And this measurement and control circuit
90 stores the value of this k, and at the time of actual measurement, this sensitivity k is used to accurately calculate the actual indentation depth of the indenter 36 from the output from this indentation depth detector 50.

The present invention is not limited to the above embodiment. For example, the present invention is not limited to the configuration of the above-mentioned embodiment except for the structure of the bearing support mechanism described above.

[Effect] As described above, according to the present invention, the play of the bearing portion of the indenter arm can be completely removed, the indenter arm can be supported accurately and smoothly, and precise measurement can be performed. , Its effect is great.

[Brief description of drawings]

1 is a schematic view of the whole device of the present invention, FIG. 2 is a perspective view of an airtight container, FIG. 3 is a front view of a measuring machine, and FIG. 4 is a front view of FIG.
Sectional view taken along line IV-IV, FIG. 5 is a schematic configuration diagram of the measurement / control device, FIG. 6 is a diagram showing changes in the supplied load current, and FIG. 7 is current detected by a current detector. Fig. 8 is a diagram showing the state of the load detected by the load detector, Fig. 9A is a diagram showing the relationship between the load current and the load,
FIG. 9B is a diagram showing the relationship between the movement amount of the depth detector and the output. 1 ... Measuring device, 2 ... Airtight container, 3 ... Measuring / control device, 4 ...
Vacuum pump, 30 ... Indenter arm, 40 ... Pushing load mechanism, 50
… Indentation depth detector, 60… Load detector, 70… Bearing support mechanism, 73,74… Needle shaft, 77… Bearing, 82…
spring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References Japanese Patent Publication Sho 62-2253 (JP, B2) Actual Publication Sho 41-16932 (JP, Y1)

Claims (3)

[Scope of utility model registration request] 1. A frame, an indenter arm rotatably supported by the frame, an indenter attached to a tip end of the indenter arm, and a pusher for applying a pushing load to the indenter by applying a torque to the indenter arm. In a micro-push type material property testing apparatus including a load mechanism and a bearing support mechanism that rotatably supports the indenter arm, the bearing support mechanism includes a bearing provided on both sides of the indenter arm and a tip end. A pair of needle shafts, each of which has a conical shape, and which projects from the frame side in opposition to each other and has a tip end axially fitted in the bearing to support the indenter arm; And a spring for urging at least one of the needle shafts so that the needle shafts come close to each other. Apparatus. 2. The spring is pressed by a pushing member movably attached to the frame side, and the urging force of the spring can be adjusted by moving the pushing member. The micro-indentation type material physical property testing apparatus according to claim 1. 3. A rod projecting from the rear end of the needle shaft biased by the spring so as to slidably penetrate the pushing member, and the needle is pulled by pulling the rod. 2. The micro push-in type material physical property testing apparatus according to claim 1, wherein the shaft is retractable against the biasing force of the spring.