JPS6042356Y2 - hardness tester - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hardness tester for measuring the hardness of the outer peripheral surface of a rotating body such as a sphere or a cylinder.

The height of the hardness distribution along the circumference of rotating bodies such as shafts, pins, steel balls, etc. affects the product life and mechanical properties. There is a need for a hardness tester that can easily and accurately measure hardness.

Conventionally, when the surface of a sample has curvature, the test surface is polished to a flat surface and then subjected to a Vickers hardness test or a Rockwell hardness test.

However, according to this method, it is time-consuming to form the test surface, the product itself is seriously damaged, the product must be discarded after the test, and there is also a process-altered layer on the surface. was generated, so there was also a problem with measurement accuracy.

Furthermore, if the radius of curvature is large to some extent, it is possible to test on a curved surface, and if necessary, the measured value is corrected and converted to hardness on a flat surface.

However, in this case too, if the radius of curvature is medium to some extent,
It is impossible to measure hardness by directly making indentations on a curved surface.

The present invention has been developed in consideration of the above circumstances, in which a rotating body is rotatably held on a rotating body mounting table, and a scratching indenter is applied to the rotating body at a certain level through a through hole provided at the bottom of the rotating body mounting table. The hardness of the outer circumferential surface of the rotating body can be accurately and efficiently determined by applying a load to the rotating body, pressing the rotating body with the rotating body drive unit, and simultaneously rotating at a constant speed to form grooves on the outer circumferential surface of the rotating body. The purpose is to provide a hardness testing machine that can continuously measure hardness.

Hereinafter, the present invention will be described in detail based on embodiments with reference to the drawings.

FIG. 1 and FIG. 2 are a plan view and a front view, respectively, showing the hardness testing machine of this embodiment.

A storage space 2 is formed inside the base 1, and a recess is formed at one end of the upper surface of the base 1, and a test surface mounting table 3 is removably fitted and fixed in this recess. A drive device 4 consisting of an air cylinder is fixed to the other end.

A piston rod 5 protrudes from the drive device 4 along the upper surface of the base 1 in the direction of the rotating body mounting table 3, and is indicated by the arrow A.
It can freely slide back and forth in the directions shown in .

At the tip of this piston rod 5, there is a piston rod 5.
The pin 6 inserted perpendicularly to the sliding direction of the arm 7
are rotatably connected around this pin 6.

However, a stopper 8 provided near the connecting portion of the arm 7 with the piston rod 5 prevents the arm 7 from colliding with the base 1 or the rotating body mounting table 3 by a certain angle or more than the extension line of the piston rod 5. The base is set not to rotate in one direction.

Further, directly above the rotating body mounting table 3, a disc-shaped weight portion 9 is detachably connected to the arm 7.

A contact surface 10 made of an elastic material such as hard rubber is attached to the lower surface of the weight portion 9.

On the other hand, a depressed portion 11 is formed on the rotary body mounting table 3, and this depressed portion 11 includes a ball, for example, to be inspected.
A rotating body 12, such as a cylinder, is rotatably held so that its rotational axis faces perpendicular to the sliding direction of the piston rod 5.

The abutment surface 10 described above has a size sufficient for one rotation of the rotary body 12, and is able to press against the rotary body 12 and slide freely according to the movement of the piston rod 5.

FIG. 3 shows an enlarged view of the rotating body mounting table 3 on which a cylinder or a cylinder is placed, and the depressed portion 11 thereof has a substantially V-shaped cross section.

Pins 14 for holding the rotating body 12 in point contact are embedded in the slope 13.13 forming the depressed portion 11.

FIG. 4 shows a rotating body mounting table 3 on which a ball is placed, and its depressed portion 11 is formed in the shape of a mortar, and pins 14 radially extend along the slope 13 of the mortar.・
... is buried.

A through hole 15 that continuously penetrates both the rotating body mounting table 3 and the base 1 opens into the storage space 2 from the bottom of the fallen portion 11 .

A pressure indenter 16 that applies a vertical load to the rotating body 12 is slidably inserted into the through hole 15, and one end thereof has a conical shape with an apex angle of 90' that contacts the outer peripheral surface of the rotating body 12. It is formed into a sharp pointed end, and the other end is the storage space 2.
It is inserted into an indenter fixture 17 provided in the indenter fixture 17 and fixed with a mounting screw 18.

The vertical load of this pressing indenter 16 is less than the pressing force from the weight portion 9.

Further, a load applying mechanism section 19 is provided inside the storage space 2.

This load applying mechanism section 19 includes a bar-shaped lever 20 and this lever 2.
It consists of a fulcrum 21 that swingably supports 0.

One end of the lever 20 is engaged with the other end of the indenter fixture 17.

The other end of the lever 20 protrudes outward from an opening in the side surface of the base 1 of the storage space 2, and a load receiving tray 22 is attached to the upper part of the opening.

An oil damper 23 is installed directly below this load receiving tray 22 to reduce impact force.

A piston rod 24 comes out from the cylinder of this oil damper 23 and is connected to a lever 20.

In addition, a support plate 25 is attached to the indenter fixture 17 inside the storage space 2.
One end is fixed, and a rod-shaped 26 is attached to the other end.
is fixed so that it can freely move up and down (in the direction of arrow B in FIG. 2).

One end of this rod 26 is connected to a differential transformer 27 that converts a change in position into an electrical signal, and the other end is connected to one end of a helical spring 28.

In addition, two leaf springs 2 parallel to each other are installed on the inner wall of the storage space 2.
One end of each of the helical springs 9 and 29 is fixed, and the other end is connected to the other end of the helical spring 28 that is not connected to the rod 26 and a part of the rod 26.

Furthermore, a cam-shaped zero adjustment knob 30 is provided that comes into contact with one of the leaf springs 29, 29.

The hardness tester of this embodiment is equipped with a groove shape measuring section (not shown) for taking out the rotating body 12 and measuring the width of the formed groove.

Next, how to use the hardness tester of the above embodiment will be explained.

First, after attaching the indenter 16 to the indenter fixture 17, the rotating body mounting table 3 corresponding to the size and shape of the rotating body 12 to be inspected is attached to the base 1. It is placed on the depressed portion 11 of the mounting table 3.

Thereafter, the contact surface 10 of the weight portion 9 is brought into close contact with the upper part of the rotating body 12, and the rotating body 12 is pressed against the fallen portion 11 with a constant load.

Next, by turning the zero adjustment knob 30, the rod 26 and the indenter fixture 17 connected and fixed thereto are slightly displaced, and the indenter 16 is brought into contact with the outer peripheral surface of the rotating body 12, thereby adjusting the zero point. do.

Furthermore, a required test load 31 is placed on the load tray 22, and a constant load is applied to the rotary body 12 via the indenter 16.

The drive device 4 is then activated to move the piston rod 5 in the direction of arrow A at a constant speed.

The arm 7 and the weight portion 9 connected to the piston rod 5 also move at a constant speed, and since the rotating body 12 is tightly pressed by the abutting surface 10, there is no possibility of slippage between the rotating body 12 and the abutting surface 10. It rotates within the depressed portion 11 at a constant speed.

At this time, the pressing indenter 16 continuously forms a pressing groove of a constant length along the outer peripheral surface of the rotating body 12.

The test load 31 after the groove shape is removed, the rotating body 12 is taken out, and the width of the groove is measured by the groove shape measuring section.

Finally, the rotation body 1 of the pressing indenter 16 is
By dividing the vertical load P (kg) with respect to 2, the hardness Hc is determined by the following formula.

HC=P/b2 Therefore, various technical analyzes are performed based on the obtained value of the stress hardness.As an example, the relationship between the position on the outer circumferential surface and the above stress hardness is plotted on a graph. There is a way to plot.

According to this method, the continuous hardness distribution on the outer circumferential surface of the rotary body 12 can be determined, and the quality of the product and the suitability of the heat treatment conditions can be determined from this.

As described above, the hardness tester of the present invention rotatably holds a rotating body on a rotating body mounting table, a pressure indenter is brought into contact with a constant load from the bottom of the rotating body mounting table, and The rotating body drive unit presses the rotating body and at the same time rotates it at a constant speed without slipping to form continuous scratch grooves along the outer circumferential surface of the rotating body, making it possible to reduce curvature, which was previously considered difficult. Hardness in the direction of the outer circumferential surface of a small rotating body can be measured continuously and efficiently.

Note that the rotary body stage in the above embodiment may be replaced with a sample stage having a depressed portion shape corresponding to the shape and size of the rotary body.

Similarly, by replacing the pressing indenter with one that corresponds to the dimensions and characteristics of the object to be inspected,
Measurement accuracy can be further improved.

Furthermore, if the test load is large, you can prevent the rotating body from lifting by placing an additional load on the top of the weight part, or you can place an additional load on the top of the weight part to prevent the rotating body from lifting up. It may also be possible to make the parts replaceable as appropriate.

Of course, various modifications can be made without departing from the gist of the thin ice invention.

[Brief explanation of drawings]

Figures 1 and 2 are a plan view and a front view of a hardness testing machine according to an embodiment of the present invention, respectively, and Figure 3 shows a rotating body mounting base of the hardness testing machine shown in Figures 1 and 2. The perspective view shown in FIG. 4 is a perspective view showing a rotary body mounting table which has a collapsed portion different from that of the rotary body mounting table shown in FIG. 3. 3... Rotating body mounting table, 10... Contact surface, 11... Fallen part, 12... Rotating body, 15... Through hole, 16... Hitsuki indenter, 19... Load loading mechanism section.

Claims (1)

[Scope of utility model registration request] a rotary body mounting table provided with a depressed portion for rotatably holding the rotating body and having a through hole bored in a lower part of the depressed portion; a rotary body drive unit having a contact surface that rotates the rotary body at a constant speed without slipping; and a hitting indenter whose end portion that is slidably inserted into the through hole and comes into contact with the outer circumferential surface of the rotary body forms a constant angle. and a load-loading mechanism section that applies a constant load to the rotating body via the indenter.