JPS6243129B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hardness meter that measures hardness based on the penetration depth of an indenter at the lower end of a load axis into a sample, and in particular, a hardness tester that measures hardness by pressing the sample onto a sample holder and fixing the sample. This invention relates to a sample-fixed hardness tester that can measure the hardness of a sample after it has been prepared.

Traditionally, in order to avoid errors in measuring the amount of penetration of the indenter into the sample, the sample is held down on a sample holder, the sample is fixed, and then a preliminary load and a main load are sequentially applied to the sample. A sample-fixed hardness tester has been proposed.

However, this type of conventional sample-fixed hardness tester requires multiple sets of load-bearing mechanisms, and as a result, operations from pressing the sample through preload to application of the test load can be carried out by applying loads on each of the load-loading mechanisms. There is a problem in that it becomes complicated due to timing and other factors.

Further, since the displacement detection mechanism and the load detection mechanism are complicated, there is also the problem of increased costs.

The present invention attempts to solve these problems by simply lowering and raising a beam that is driven vertically along the hardness tester body, from pressing the sample to applying preload and test load. This is a sample-fixed hardness tester that enables a series of operations up to and vice versa, and uses two leaf springs to accurately apply preload and test load. The purpose is to provide

For this reason, the sample-fixed hardness meter of the present invention has a beam that is driven vertically along the hardness meter body above the sample holder, and a beam that is supported from above by the support section of the beam. a cylindrical sample holding member provided so as to be movable up and down relative to the sample holding member; a displacement detector integrally attached to one of the load axis and the sample holding member along the central axis thereof, and a displacement detector integrally attached to the other of the load axis and the sample holding member. a pair of plates that are arranged in upper and lower stages along the beam and capable of pressing the upper end of the load shaft in order to apply a preliminary load and a test load through the load shaft; It is characterized by the provision of a spring.

Hereinafter, a sample-fixed hardness tester as an embodiment of the present invention will be explained with reference to the drawings. Fig. 1 is a front view thereof, Fig. 2 is an enlarged partial view of the part shown in Fig. 1, and Fig. 3 is a partial view showing the portion shown in Fig. 1. Fig. 4 is a partial perspective view for explaining the beam guiding mechanism, Fig. 5 is an enlarged view of the vicinity of the indenter, and Fig. 6 is its operation. timing diagram,
FIG. 7 is a block diagram showing the measurement system.

As shown in FIG. 1, a gate-shaped support frame 3 is rigidly erected on a bed 1, and the bed 1 and support frame 3 constitute a hardness tester main body H.

Further, a sample holder 2 is provided on the bed 1, and a sample 13 is placed on this sample holder 2.

Furthermore, screw shafts 4 extending in the vertical direction are provided on both inner sides of the support frame 3, and these screw shafts 4 are connected to a motor 102 with a clutch (the second (see Figure 7) so that they can be rotated synchronously in the same direction.

As shown in FIG. 4, nuts 29 with guide pieces 30 are screwed onto these screw shafts 4, and each guide piece 30 is fitted into a guide groove 3a of the support frame 3. Between these guide pieces 30,
A pair of support plates 5 as beams are mounted.

As a result, these support plates 5 are integrated,
Above the sample holder 2, it is driven in the vertical direction along the hardness meter main body H.

By the way, as shown in FIG.
A guide member 28 is provided in between, and a cylindrical sample holding member 27 is fitted into the guide portion passing through the guide member 28 vertically so as to be movable in the vertical direction.

At the upper end of this sample holding member 27,
The connecting plate 26 is fixed with bolts or the like,
The lower surface of the connecting plate 26 is the upper end support portion 2 of the guide member 28.
8a. As a result, the sample holding member 27 is inserted into the supporting plate 5 from above via the connecting plate 26.
This means that it is supported by a guide member 28 with an attached guide member 28.

Note that a cylindrical sample holding part 15 having a predetermined length is fixed to the lower part of the sample holding member 27 with a bolt or the like.

A load shaft 19 is fitted coaxially within the sample holding member 27, and a conical enlarged receiving portion 19a is formed in the middle portion of the load shaft 19. Between the side flange-shaped spring receiving surface and the spring receiving surface of the sample holding part 15,
A spring 18 is interposed to bias the load shaft 19 upward.

The spring 18 causes the receiving portion 19a of the load shaft 19 to come into contact with the stopper portion 27a of the sample holding member 27 from below, thereby restricting the upward movement of the load shaft 19 while holding the sample. It is adapted to be supported by a member 27. Therefore, by pushing down the load shaft 19 against the spring 18, the load shaft 19 is moved against the sample holding member 2.
It can be lowered independently from 7. Note that when the pressing force is loosened, due to the bias of the spring 18,
The load shaft 19 rises.

Further, as shown in FIGS. 3 and 5, an indenter 14 is attached to the lower end of the load shaft 19 so as to be inserted into the sample holding part 15.

The connecting plate 26 with the sample holding member 27 includes
A displacement gauge support member 24 is attached via four connecting rods 25, and this displacement gauge support member 24
A displacement meter (displacement detector) 9 is attached via. The displacement meter 9 is arranged along the central axis of the sample holding member 27.

Further, a connecting plate 20 is attached to the upper end of the load shaft 19, and a connecting plate 22 having the same shape as the connecting plate 20 is attached to this connecting plate 20 via four connecting rods 25. , to this connecting plate 22,
Contact piece (contact member) that contacts the displacement meter 9 from below
23 are provided.

Between the support plates 5, 5, there is a first plate along the longitudinal direction.
The leaf spring 11a and the second leaf spring 11b are arranged in two stages, upper and lower. And these leaf springs 1
1a and 11b are supported by the support plate 5 so that both ends thereof are held between three shafts 6a, 6b, and 6c as shown in FIGS.

In addition, as shown in FIGS. 1 to 4, support plates 5, 5
A support rod 31 is interposed between the pair of leaf springs 11a and 11b to support the middle part (center part) of the leaf spring (second leaf spring 11b) from below. It is arranged so as to be guided along a long hole 5a formed in the plate 5.

Further, the support rod 31 is supported by a pillow member 32 fitted into the elongated hole 5a so that the support rod 31 can support the second leaf spring 11b with the center portion of the second leaf spring 11b slightly lifted. . This gives preliminary deformation to the second leaf spring 11b.

Note that the first leaf spring 11a is used for applying a preliminary load, and the test load is applied by the first leaf spring 11a and the second leaf spring 11b.

Therefore, the spring constant of the first leaf spring 11a is set smaller than that of the second leaf spring 11b.

By the way, on the lower side of the longitudinal center portion of the first leaf spring 11a, there is a portion facing the upper end of the load shaft 19 and
A load cell (load detector) 10 is attached along the central axis of the load cell 9 . As a result, this load cell 10 has the first plate spring 11 attached to the support plate 5.
It is supported elastically via a,
Furthermore, when the load cell 10 comes into contact with the load shaft 19 and a load is transmitted as the support plate 5 descends, the load cell 10 can detect the applied load from the preload state to the test load state.

A conical enlarged receiving portion 27b is formed at the lower part of the sample holding member 27, and a sample holding plate (holding intermediate member) 12, which also has a conical receiving surface, is provided on this receiving portion 27b. It is being

Furthermore, a pair of left and right L-shaped levers 7 facing each other are pivotally mounted on the outer surfaces of both support plates 5.
A contraction spring 8 is interposed between the long arm portions of the left and right levers 7. (See Fig. 1) Furthermore, a roller 16 is provided between the short arms of the left and right levers 7 that face each other with the support plate 5 in between.
A shaft 17 is mounted thereon, and the roller 16 of this shaft 17 is in contact with the pressing plate 12.

Thereby, the biasing force exerted by the spring 8 can be magnified by the lever 7 and transmitted to the holding plate 12.

The support plate 5 is provided with a stopper pin 3 in order to prevent the lever 7 from rotating further in the contraction direction of the spring 8 than the predetermined position due to contraction by the spring 8.
3 is provided in a protruding manner, whereby the urging force by the spring 8 transmitted to the presser plate 12 via the lever 7 can be maintained at a predetermined value or more.

By the way, as shown in FIG. 7, the detection signals from the displacement meter 9 and the load cell 10 are sent to the drive motor 102 of the screw shaft 4, the control section 101 for the clutch, and the Brinell hardness of the sample through the interface 100. The data is sent to the calculation/display/recording section 103 which calculates, displays, and records the HB.

Then, the motor control unit 101 receives each detection signal of displacement and load, and according to the measured displacement and load,
By controlling the motor 102 and a clutch (not shown), the load F and displacement x as shown in FIG.
and characteristics A, B, and C of the pressing force f.

Further, the calculation/display/recording unit 103 receives the detection signal corresponding to the displacement x, calculates the Brinell hardness HB of the sample by calculating the following equation based on the detection signal, and further displays and records the result.

HB=(A/Δx)+B Here, Δx (mm) is the difference in the displacement x of the indenter 14 when the preload is applied twice before and after the preload is applied, which is obtained by a series of operations of this hardness tester.

In addition, A and B are constants obtained through experiments, for example, the preliminary load is 300Kgf, the test load is 3000Kgf,
If the diameter of the indenter 14 is 10 mm, A≒47, B≒66
becomes a constant.

With the above configuration, in order to measure the Brinell hardness HB of a sample, a desired sample 13 is first placed on the sample holder 2.

Thereafter, the motor 102 is driven while controlling its rotational state (including the engagement/disengagement state of the clutch) according to the timing chart shown in FIG. First, between time t ₀ and t ₁ , the motor 102 is rotated rapidly to lower the support plate 5 at high speed.
Thereafter, at time _t1 , that is, when the lower end of the sample holding part 15 is close to the surface of the sample 13, the speed of the motor 102 is reduced. As a result, the support plate 5 descends at a low speed.

Then, at time _t2 , the lower end of the sample holding part 15 comes into contact with the surface of the sample 13. As a result, the connecting plate 26 with the sample holding member 27 is separated from the guide member 28, so that the biasing force of the spring 8 is expanded by the lever 7 and applied to the sample surface via the holding plate 12 and the sample holding part 15. It takes time
At t ₃ , the fully expanded spring bias force is applied to sample 1.
It takes 3. As a result, the unevenness on the back surface of the sample 13 is crushed and the sample 13 is fixed.

Note that the reason why the pressing force f suddenly rises at time _t2 is because the stopper pin 33 is configured to prevent the biasing force from the spring 8 from becoming smaller than a predetermined value. A pressing force of 1,700 Kgf in this embodiment can be applied in a short period of time.

As the support plate 5 further goes down, the load cell 10 comes into contact with the load shaft 19 at time _t4 , and then the load shaft 19 gradually goes down. At this time, load axis 1
The posture of 9 is maintained by a load cell 10. Then, the indenter 14 presses the sample surface and
At T ₅ , a preload is applied.

At this time, the motor 102 is temporarily stopped,
Zero-set the displacement meter 9 while maintaining the preload state.

In this state, the biasing force by the second leaf spring 11b is not acting, and the biasing force by the first leaf spring 11a, the weight of the load shaft 19, etc. are acting on the sample surface via the load shaft 19 and the indenter 14. There is.

After the above zero setting is completed (at time _t6 ), the motor 102 is driven at low speed again to lower the support plate 5. As a result, as the load increases on the sample 13, the output of the displacement meter 9 also changes. Then, after time _t7 , at time _t8 , a test load is applied.

In this state, in addition to the biasing force of the first leaf spring 11a and the weight of the load shaft 19, the biasing force of the second leaf spring 11b also acts.

Note that the reason why the load F suddenly rises at time _t7 is because the second leaf spring 11b is pre-deformed by the support rod 31, which shortens the desired test load. You can spend some time on it.

In this state, the total sample pressing force is set to be as large as possible so that the change in posture between the preload and the sample load is tolerable for hardness measurement.

At this time, the motor is stopped once again to maintain the test load state, and then the motor 10 is
2 in the opposite direction at a low speed to raise the support plate 5, a preload is applied again at time _t11 after time _t9 and _t10 .

At this time, the motor 102 is temporarily stopped,
The displacement x is detected by the displacement meter 9 while maintaining the preload state.

Note that in this state, as described above, the biasing force by the second leaf spring 11b is not acting, but the sample 1
Due to the plastic deformation of No. 3, there is a difference in the displacement of the indenter 14 during the two preloads, before and after. Then, this displacement difference Δx (actually, the zero setting of the displacement meter 9 is performed in the first preload state, so the second
The displacement during the second preload corresponds to this displacement difference. ), the above formula HB=(A/Δx)+B is calculated, and based on the result of this calculation,
Brinell hardness HB will be displayed and recorded.

Note that at a desired time _t12 after the calculation is completed, the motor 102 is rotated at an even higher speed.

As a result, the load cell 10 first separates, and the displacement meter 9 separates from the contact piece 23 (at time t ₁₃
), and finally at time t ₁₄ , sample holding part 1
5 begins to separate from the sample 13, and at time _t15 , the sample holding part 15 completely separates from the sample 13.

Then, at time _t16 , the hardness measurement operation is completed by stopping the motor 102, but all of the above operations are performed automatically.

Alternatively, the displacement meter 9 may be integrally attached to the load shaft 19 side, and the contact piece 23 may be integrally attached to the sample holding member 27 side.

As described in detail above, the fixed sample hardness tester of the present invention provides the following effects and advantages.

(1) The operation of holding the sample, applying the preliminary load, and applying the test load can be achieved by simply lowering the beam, simplifying the operation and making it easy to automate.

(2) Since a pair of leaf springs are arranged in two stages above and below along the beam, first apply a preload to the lower leaf spring, then apply a test load to the upper leaf spring. This allows both the preload and the test load to be applied accurately.

(3) After the test load is applied from the preload state, the hardness is measured again based on the relative displacement between the preload state and the previous and subsequent preload states. The error due to the amount of strain compared to the test load is canceled,
Measurement accuracy can be increased.

(4) The displacement detector is built into the hardness tester so that it is arranged along the central axis of the sample holding member and the load shaft, so it has a simple configuration.
Relative displacement can be detected with high accuracy.

(5) It can be easily applied to large samples and also to the measurement of Brinell hardness.

[Brief explanation of the drawing]

The figures show a sample-fixed hardness tester as an embodiment of the present invention. Fig. 1 is a front view thereof, Fig. 2 is an enlarged partial view of the part shown in Fig. 1, and Fig. 3 is a partial view of the part shown in Fig. 1. FIG. 4 is a partial perspective view for explaining the mechanism for guiding the beam, FIG. 5 is an enlarged view of the vicinity of the indenter, and FIG.
The figure is an operation timing diagram, and FIG. 7 is a block diagram showing the measurement system. 1...Bed, 2...Sample holder, 3...Support frame, 3a...Guide groove, 4...Screw shaft, 5...Support plate as beam, 5a...Elongated hole, 6a, 6b,
6c...Shaft, 7...Lever, 8...Spring, 9...
Displacement meter as a displacement detector, 10... Load cell as a load detector, 11a, 11b... Leaf spring, 12... Holding plate as a holding intermediate member, 13... Sample, 14... Indenter, 15 ...Sample holding part, 16...Roller, 17...Shaft, 1
8... Spring, 19... Load shaft, 19a... Receiving part,
20... Connecting plate, 21... Connecting rod, 22... Connecting plate, 23... Contact piece as a contact member, 24...
Displacement meter support material, 25... Connection rod, 26... Connection plate, 27... Sample holding member, 27a, 27b
...Receiving part, 28...Guiding member, 28a...Supporting part, 29...Nut, 30...Guiding piece, 31...
Support rod, 32...Pillow member, 33...Stopper pin, 100...Interface, 101...Control unit, 102...Motor, 103...Calculation/display/recording unit, H...Durness meter main body.

Claims (1)

[Claims] 1. Above the sample holder, a beam driven vertically along the hardness tester body and a beam supported from above by a support section of the beam are moved vertically relative to each other. A cylindrical sample holding member is provided, and a load shaft is supported by the sample holding member and is provided so as to be movable up and down coaxially with the sample holding member and independently of the sample holding member. , a displacement detector integrally attached to one of the load shaft and the sample holding member along the central axis thereof, and a contact member integrally attached to the other and in contact with the displacement detector. In addition, in order to apply a preliminary load and a test load via the load shaft, a pair of leaf springs are provided along the beam in two stages, upper and lower, and capable of pressing the upper end of the load shaft. A sample-fixed hardness tester featuring: 2. A conical receiving part is formed at the lower part of the sample holding member, and an intermediate holding member is provided on the receiving part from above, and an L-shaped lever is pivotally attached to the beam, and an L-shaped lever is attached to the beam. The sample-fixed hardness tester according to claim 1, further comprising a spring, and the urging force of the spring is amplified by the lever and transmitted to the pressing intermediate member. . 3. Claim 2, further comprising a stopper pin that restricts rotation of the lever in order to maintain the biasing force of the spring transmitted to the pressing intermediate member via the lever at a predetermined value or more. The sample-fixed hardness tester described. 4 A spring that biases the load shaft upward is interposed between the load shaft and the sample holding member, and a spring is inserted between the load shaft and the stopper portion of the sample holding member from below. The sample-fixed hardness tester according to claim 1, wherein a conical receiving portion is formed to abut against and restrict upward movement of the load shaft. 5. In order to give preliminary deformation to the upper leaf spring of the pair of leaf springs, a support rod is provided on the beam to support the upper leaf spring from below so as to slightly lift the middle part of the upper leaf spring. The sample according to claim 1, wherein the support rod is arranged to be guided along an elongated hole formed in the beam so as to allow the support rod to move upward. Fixed hardness meter. 6 Based on the displacement difference Δx obtained from the detection signal from the displacement detector before and after applying the preload twice, the Brinell hardness HB of the sample can be calculated from the following formula:
The sample-fixed hardness tester according to claim 1, which is provided with a calculator for calculating . HB=(A/Δx)+B where A and B are constants obtained through experiment.