JP2000298090A - Hydraulic birnell hardness tester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply an oil in a short time while an inertial force does not act on an additional plumb by using a motor-driven pump by providing a speed control means which changes the rotational speed of a motor at a time when a pressure detection means detects that an oil pressure reaches a prescribed oil pressure. SOLUTION: When the supply of an oil 16 is started, a piston 12 for load is pressed by the oil 16 so as to be lowered, and an indenter 15 which is installed at the tip of the piston 12 for load creeps into a sample on a sample receiver base 11. When the indenter 15 creepts into the sample to a certain extent so as to be stopped, an oil pressure is increased gradually, and it is measured by an oil pressure gage 31. When the oil pressure reaches a prescribed set pressure, a changeover signal is output to a speed changeover switch 41. At this time, the speed of a motor is changed over to a second slow speed from a first speed by the speed changeover switch 41, and the oil can be supplied automatically so as not to generate an inertial force. In addition, when the oil is supplied at speeds in two steps in this manner, the time required for a hardness test can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a hydraulic Brinell hardness tester.

[0002]

2. Description of the Related Art The principle of a hydraulic Brinell hardness tester is shown in FIG.
This will be described with reference to FIG. First, when the oil 102 is injected into the oil passage 101 by the oil supply pump, the load piston 103 is pressed by the oil 102, and the indenter 105 provided at the tip of the load piston 103 hits the sample placed on the sample receiving table 104.
The loading piston 103 initially sinks because the indenter 105 sinks into the sample, but stops when it reaches a certain extent. When the oil 102 is further injected, the additional weight 106 is lifted, and the piston 103 for load is applied according to the principle of Pascal.
A certain force will be applied. The hardness can be calculated by measuring the diameter of the depression formed in the sample by the indenter 105 using the determined force.

In such a hydraulic Brinell hardness tester, a means for injecting oil 102 into an oil passage 101 is shown in FIG.
As shown in FIG. 5, the lever 201 is manually moved to raise and lower the piston 202 to supply oil, or the eccentric cam 301 is rotated by a motor (not shown) as shown in FIG. A motor-driven pump that supplies oil by raising and lowering the oil is used.

[0004]

However, if a large amount of oil is supplied at one time during the oil supply process, the additional weight moves rapidly, so that the inertia acts on the additional weight and the extra force is applied to the indenter. From the sample to the sample. In the case of the supply by the motor drive as shown in FIG. 5, since the supply is performed at the same speed from the start of the supply to the completion of the supply, an inertial force is generated. To prevent this inertial force, the rotation of the motor that rotates the eccentric cam 301 may be slowed down, but the supply takes too much time. In the case of manual supply as shown in FIG. 4, the worker performs the supply operation while looking at the load indicating device 107, and when approaching the set test force, operates the lever 201.
Can be operated slowly to prevent such inertial force from acting on the additional weight, but it takes time because it is performed manually.
Manpower is required.

An object of the present invention is to provide a hydraulic Brinell hardness tester using a motor-driven pump.
The purpose is to enable oil to be supplied in a short time while preventing inertial force from acting on the added weight.

[0006]

According to the first aspect of the present invention, an oil (16) is supplied to a tester main body (1) by an oil supply pump driven by a motor. In a motor-driven hydraulic Brinell hardness tester 16), a predetermined pressure is transmitted to a sample via an indenter 15 by lifting an additional weight 13 in 16). Pressure detecting means (3) for measuring the oil pressure of the oil (16), and detecting that the oil pressure has reached a predetermined oil pressure before the operation of the additional weight (13); and the pressure detecting means (3). And speed control means (4) for changing the rotation speed of the motor when it detects that the oil pressure has reached the predetermined oil pressure.

Here, the predetermined pressure before the operation of the additional weight can be arbitrarily set according to the weight of the additional weight or the like, and the setting may be automatic or manual. Further, the rotational speed of the motor is assumed to be reduced by the speed control means as compared to before the speed is controlled, and the speed may be reduced in two steps or multiple steps, or may be reduced continuously.

As described above, according to the first aspect of the present invention, the pressure detecting means measures the oil pressure in the tester main body, and this oil pressure is reduced to a predetermined pressure before the set additional weight operates. When it reaches, the speed control means reduces the rotation speed of the motor so that the supply of oil can be delayed before the additional weight starts to move, so that the additional weight moves slowly and the inertial force does not work. Therefore, the supply operation of the oil that does not require inertia force can be automatically performed. In addition, since the oil can be rapidly supplied before the speed control is performed, the test time for one cycle can be reduced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic Brinell hardness tester according to the present invention will be described below with reference to FIGS.

<First Embodiment> FIG. 1 is a schematic diagram of a hydraulic Brinell hardness tester provided with an oil pressure gauge as pressure detecting means and a speed changeover switch as speed control means. The tester is generally composed of a main body 1, a refueling pump 2, a pressure detector 3, and a speed controller 4 of a hydraulic Brinell hardness tester.

The main body 1 of the hydraulic Brinell hardness tester is roughly composed of a sample holder 11, a load piston 12, an additional weight 13, and an oil passage 14. The oil passage 14 has an additional weight 13 and a load. The piston 12 and the oil pressure gauge 31 are connected. An indenter 15 is provided at the tip of the loading piston 12. The indenter 15 sinks into the sample on the sample receiving table 11 when the loading piston 12 is immersed in oil 16 and falls.

The refueling pump 2 is of a motor-driven type,
And two tubes 21 and 22 and a cylinder 23.
The piston 24 that slides inside 3 is connected to an eccentric cam 26 via a bearing 25, and the eccentric cam 26 is connected to a motor (not shown). The pipes 21 and 22 are provided with check valves 27 and 28, respectively.

The pressure detecting means 3 includes an oil pressure gauge 31. The oil pressure gauge 31 measures the oil pressure in the oil passage 14, and when the oil pressure reaches the set oil pressure, the switching signal is subjected to speed control. Output to means 4. The speed control means 4 includes a speed changeover switch 41, and the speed changeover switch 41 switches the switch according to a changeover signal from the pressure detection means 3. The rotation speed of the motor is changed by switching this switch.
The speed is switched from the fast first speed to the second speed slower than the first speed. Here, the predetermined hydraulic pressure is a design item determined by the structure of the hardness tester or the test load. As an example, the sectional area of the cylinder on which the pressurizing piston 17 provided under the additional weight 13 slides is S ₁ , the sectional area of the cylinder on which the load piston 12 slides is S ₂ ,
This area ratio is S ₁ : S ₂ = 1: 109, and the indenter 15 has 29
When a force of 421 N (3000 kgf) is to be applied, the hydraulic pressure is about 3.4 MPa, so that the switching is performed when the hydraulic pressure gauge 31 detects 3.0 MPa.

Subsequently, a hardness test operation using the hydraulic Brinell hardness tester will be described. The sample is placed on the sample holder 11 of the main body 1 of the hydraulic Brinell hardness tester, and the supply of the oil 16 to the oil passage 14 is started by using the oil supply pump 2.
At this time, a predetermined oil pressure before the additional weight 13 starts to move is adjusted according to the weight of the sample and the additional weight 13, etc.
Set to. When the motor of the refueling pump 2 rotates at a constant speed and the eccentric cam 26 starts rotating, the piston 24 starts moving up and down in the cylinder 23. When the piston 24 rises, the check valve 27 opens and the cylinder 2
3 is filled with oil 16. When the piston 24 is lowered, the oil 16 in the cylinder 23 is pushed out, the check valve 28 is opened, and the oil 16 is injected into the tester main body 1 through the pipe 22.

As described above, when the supply of the oil 16 is started,
The loading piston 12 is pushed down by the oil 16 and descends. The indenter 15 provided at the tip of the loading piston 12 is
Dive into the sample above. When the indenter 15 enters the sample to some extent and stops, the hydraulic pressure gradually increases. At this time, the oil pressure is measured by the oil pressure gauge 31, and when the oil pressure reaches a predetermined oil pressure, a switching signal is output to the speed changeover switch 41. With this switching signal, the hydraulic speed changeover switch 4
1 switches the rotation speed of the motor from the first speed to a second speed lower than the first speed. As a result, the vertical movement of the piston 24 is also slowed down, and the speed at which the oil 16 is supplied to the tester main body 1 is also slowed down. Therefore, the additional weight 13 is slowly lifted to the extent that inertial force does not work, and only the determined force is applied to the indenter 1.
5 through the sample.

After the force determined by the additional weight 13 is applied to the sample, the oil 16 is removed, the load piston 12 is raised, and the sample is taken out. The size of the dent formed by the indenter 15 formed on the sample is measured, and the hardness of the sample is calculated.

As described above, according to the hydraulic Brinell hardness tester of the above-described embodiment, when the oil pressure reaches the oil pressure before the additional weight 13 moves, the speed changeover switch 41 changes the motor speed to the speed. By switching from the fast first speed to the slow second speed, automatic lubrication without inertial force can be performed. Further, by supplying the oil at such a two-stage speed, the time required for the hardness test can be reduced.

<Second Embodiment> FIG. 2 shows a hydraulic pressure gauge, an A / D converter, a hydraulic pressure judging circuit and the like as pressure detecting means, and a speed control circuit and a D / A conversion as speed controlling means. 1 is a schematic diagram of a hydraulic Brinell hardness tester provided with a device and the like. The hydraulic Brinell hardness tester is roughly composed of a main body 1, an oil supply pump 2, a pressure detection means 3, and a speed control means 4 of the hydraulic Brinell hardness tester. The configurations of the hydraulic Brinell hardness tester main body 1 and the hydraulic pump 2 are the same as those in the first embodiment described above.

The pressure detecting means 3 includes an oil pressure gauge 31, an A / D converter 32, an oil pressure judgment circuit 33 and the like. The oil pressure gauge 31 measures the oil pressure in the oil passage 14 and outputs an oil pressure data signal to the A / D converter 32. The A / D converter 32 converts a hydraulic data signal into a digital signal. The oil pressure determination circuit 33 determines whether or not the oil pressure data signal digitized by the A / D converter 32 has reached a set predetermined oil pressure value, and determines that the oil pressure data signal has reached the predetermined oil pressure value. To
The determination signal is output to the speed control means 4. Speed control means 4
Includes a speed control circuit 42, a D / A converter 43, and the like. The speed control circuit 42 generates a deceleration signal for decelerating the rotation of the motor of the oil supply pump 2 based on the determination signal output from the oil pressure determination circuit 33 and outputs the signal to the D / A converter 43. The D / A converter 43 converts the deceleration signal output from the speed control circuit 42 into an analog signal and outputs the analog signal to the motor to reduce the rotation of the motor. The rotation speed of the motor can be set freely.

Next, a description will be given of a hardness test operation using the hydraulic Brinell hardness tester. As in the first embodiment, a sample is set on the tester main body 1, a predetermined oil pressure is set before the additional weight 13 starts to move, and oil 16 is supplied to the oil passage 14 of the tester main body 1. When started, the motor of the refueling pump 2 rotates at the first speed, and the piston 24 starts to move up and down via the eccentric cam 26. When the oil 16 is supplied to the tester main body 1, the load piston 12 descends,
The indenter 15 at the tip sinks into the sample. When the indenter 15 stops, the oil pressure in the oil passage 14 increases. The increase in oil pressure is measured by an oil pressure gauge 31. When the pressure detection means 3 detects that the oil pressure has reached the set predetermined oil pressure, the speed control means 4 reduces the rotation speed of the oil pump 2 motor. As a result, the up-and-down movement of the piston 24 becomes gentle, and the supply speed of the oil 16 to the test machine main body 1 becomes slow.

Then, as in the first embodiment, the oil 1
6, remove the sample by raising the load piston 12,
The size of the depression formed in the sample is measured, and the hardness of the sample is calculated.

As described above, according to the hydraulic Brinell hardness tester of the above-described embodiment, the pressure detecting means 3 makes the hydraulic pressure of the tester main body 1 reach the predetermined hydraulic pressure before the additional weight 13 starts to move. Is detected, the refueling speed is reduced by the speed control means 4, so that automatic refueling with no inertial force can be performed. In addition, since the refueling speed is reduced after the refueling has been performed to some extent, the time required for the hardness test can be reduced.

In the above embodiment, the speed control circuit and the speed changeover switch are used as the speed control means. However, the present invention is not limited to this. What is necessary is just to be able to control in two steps. Also, the motor-driven refueling pump is not limited to the piston pump, but can be applied to a pump other than the piston pump, for example, a volute pump. The shape and the like of the hydraulic Brinell hardness tester main body of the embodiment are also arbitrary, and it goes without saying that the specific detailed structure and the like can be appropriately changed. As an example of the predetermined pressure to be set, the pressure (3.10%) lower than the hydraulic pressure (3.4 MPa) at which the additional weight starts to move.
0 MPa), but this ratio is not limited to this, and may be set arbitrarily according to the hydraulic pressure at which the additional weight starts to move.

[0024]

As described above, according to the hydraulic Brinell hardness tester according to the first aspect of the present invention, the oil pressure in the tester main body is measured by the pressure measuring means, and this oil pressure is set. When the pressure reaches a predetermined pressure before the operation of the additional weight, the supply of oil can be delayed before the additional weight starts moving by reducing the rotation speed of the motor by the speed control means, so that the additional weight moves slowly. , Inertia will not work. Therefore, the supply operation of the oil that does not require inertia force can be automatically performed. In addition, since the oil can be rapidly supplied before the speed control is performed, the test time for one cycle can be reduced.

[Brief description of the drawings]

FIG. 1 shows a first embodiment of the present invention.
1 is a schematic diagram of a hydraulic Brinell hardness tester provided with a hydraulic pressure gauge as a pressure detecting means and a speed changeover switch as a speed controlling means.

FIG. 2 shows a second embodiment to which the present invention is applied.
1 is a schematic diagram of a hydraulic Brinell hardness tester that includes a pressure gauge, an A / D converter, a hydraulic pressure determination circuit, and the like in a pressure detection unit, and a speed control circuit, a D / A converter, and the like in a speed control unit.

FIG. 3 is a sectional view showing a structure of a main body of the hydraulic Brinell hardness tester.

FIG. 4 is a cross-sectional view showing a structure of a conventional manual pump which is a means for injecting oil into a conventional hydraulic Brinell hardness tester main body.

FIG. 5 is a cross-sectional view showing the structure of a motor-driven pump as a means for injecting oil into a conventional hydraulic Brinell hardness tester main body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic type Brinell hardness tester main body 2 Oil supply pump 3 Pressure detection means 4 Speed control means 11 Sample receiving stand 12 Loading piston 13 Additional weight 14 Oil passage 15 Indenter 16 Oil 17 Pressurizing piston 21 Tube 22 Tube 23 Cylinder 24 Piston Reference Signs List 25 bearing 26 eccentric cam 27 check valve 28 check valve 31 oil pressure gauge 32 A / D converter 33 oil pressure judgment circuit 41 speed switch 42 speed control circuit 43 D / A converter 101 oil passage 102 oil 103 oil 103 load piston 104 sample Cradle 105 Indenter 106 Additional weight 107 Load indicating device 201 Lever 202 Piston 301 Eccentric cam 302 Piston

Claims (1)

[Claims] 1. A motor driven hydraulic Brinell which supplies oil to a tester main body by an oil supply pump driven by a motor, and transmits a predetermined pressure to a sample via an indenter by lifting an additional weight with the oil. In a hardness tester, a pressure detector that measures the oil pressure of the oil supplied to the tester main body and detects that the oil pressure has reached a predetermined oil pressure before the operation of the additional weight, A hydraulic Brinell hardness tester, comprising: speed control means for changing the rotation speed of the motor when it detects that the oil pressure has reached the predetermined oil pressure.