Hardness tester

Abstract

In order to provide a hardness testing machine that can set the load range of the indenter over a wider range, the hardness testing machine 10 includes: a base member 120 supported in a freely lifting and lowering position; a motor 110 serving as a drive device to drive the lifting and lowering action of the base member 120; and a pressure sensor switching device 130, which includes a first pressure sensor 141 with a first indenter connecting member 141a and a second pressure sensor 142 with a second indenter connecting member 142a, and is provided on the base member 120 in such a way that the first pressure sensor 141 and the second pressure sensor 142 can be switched.

Description

Hardness tester This invention relates to a hardness testing machine. In the past, hardness testing machines equipped with pressure sensors (load sensors) have been disclosed. For example, the hardness testing machine disclosed in Japanese Patent Publication No. 2016-206094 is equipped with: an indenter; a load sensor for detecting a specified load applied to the indenter; and a position sensor for determining the position of the platform on which the test object is placed, in order to perform high-precision measurements even on soft test objects such as gel-like organic materials or biological substances. While hardness testing machines are available for specific applications, there is also a demand for machines capable of testing the hardness of various materials using a single machine. In other words, it is desirable to use a single machine to test materials ranging from low to high hardness. In such cases, a lower load is applied to the indenter to create an indentation for softer materials, while a higher load is applied for harder materials. Furthermore, in addition to loads specified in the design specifications, there are also instances where arbitrary loads are applied to the indenter. The purpose of this invention is to provide a hardness testing machine that allows the load range of the indenter to be set to a wider range. The hardness testing machine of the present invention is characterized by having: a base member supported in a freely lifting and lowering manner, a drive device for driving the lifting and lowering action of the base member, and a pressure sensor switching device. The pressure sensor switching device includes a first pressure sensor with a first indenter connecting member and a second pressure sensor with a second indenter connecting member, and is provided on the base member in such a way that the first pressure sensor and the second pressure sensor can be switched. This invention provides a hardness testing machine that allows for setting the load range of the indenter to a wider range. [First Embodiment] The first embodiment of the present invention will be described with reference to the drawings. The hardness testing machine 10, viewed from the side, is roughly C-shaped and includes: a base 11 with feet 12 for mounting, a support 13, and a head 14. A sample stage assembly 20 is provided on the base 11. The sample stage assembly 20 has a worktable (not shown) for holding samples, which can be adjusted for height and other changes by manually rotating a handle (not shown). Furthermore, an operation panel 15 for various operations or settings is provided on the front of the base 11. Furthermore, in the following description, the upper side of the hardness testing machine 10 is called the upper side, the lower side is called the lower side, the side with the operation panel 15 is called the front (or front), and the opposite side is called the back (or rear). The left side of the hardness testing machine 10 viewed from the front is called the left side, and the right side is called the right side. A rotating device 30 is provided at the head 14 opposite to the sample stage device 20. The rotating device 30 is mounted on a circular rotating disk 31, which is equipped with a pressure head unit 320 with a pressure head 32 and an objective lens 33, allowing for appropriate selection depending on the operation. Furthermore, although not shown in the figure, a plurality of pressure heads 32 and objective lenses 33 can be provided on the rotating disk 31. The rotating disk 31 is rotatable about an inclined axis 31a; however, when the pressure head 32 or objective lens 33 is positioned at a selected position on the axis 20a of the sample stage device 20, the axis of the pressure head 32 or objective lens 33 is aligned with the axis 20a of the sample stage device 20. A load-bearing unit 100 can be installed inside the head 14. Hereinafter, the load-bearing unit 100 will be described in detail with reference to Figures 2 to 6. As shown in the oblique views of the load-bearing unit 100 in Figures 2 to 4, the load-bearing unit 100 has a fixing plate 101 at its lower part, the flat side of which is parallel to the horizontal direction. The fixing plate 101 is fixed to the internal structure of the head 14 of the hardness testing machine 10. A motor 110 is provided in the fixing plate 101 as a drive device to drive the lifting and lowering action of the base member 120 (described later). Motor 110 is configured with its output shaft facing upwards in the vertical direction. The output shaft of motor 110 is connected to a gear inside gearbox 111 (not shown). The output shaft originating from gearbox 111 is also configured with its vertical direction facing upwards. The output shaft originating from gearbox 111 is connected to coupling 112 provided on fixed plate 101. Coupling 112 is connected to ball screw shaft 113a of ball screw mechanism 113. Ball screw shaft 113a is screwed into nut 113b of ball screw mechanism 113. Nut 113b is fixed to base member 120. The base member 120 is formed in a slightly plate-like shape, configured slightly parallel to the fixed plate 101, and supported so as to be freely movable relative to the fixed plate 101. Specifically, the base member 120 is provided with: a sliding member, which is a guide post 121 fixed to the left and right sides of the rear side of the fixed plate 101; and a movable member, which is a sliding guide seat 122 fixed to the left and right sides of the front side of the fixed plate 101. The nut 113b of the ball screw mechanism 113 is disposed between the guide posts 121 on the rear side of the base member 120. A sensor base 102, which appears slightly L-shaped when viewed from the side, is provided at the rear end of the fixed plate 101. Three light sensors 103 are provided on the upper surface of the sensor base 102. Each light sensor 103 has a set of light-emitting / light-receiving elements. On the other hand, a plate-shaped detection member 123 is provided on the right side of the rear end of the base member 120. This detection member 123 can be inserted between the light-emitting / light-receiving elements of the light sensors 103. The detection members 123 are formed with different lengths. The three light sensors 103 can detect the upper and lower limits of the base member 120. In addition, by placing the light sensors 103 at the rear of the load-bearing unit 100, maintenance of the light sensors 103 can be easily performed by simply removing the back cover of the support column 13 of the hardness testing machine 10. A pressure sensor switching device 130 is provided on the front side of the base member 120. In the pressure sensor switching device 130, a slightly rectangular guide portion 131, longer in the left-right direction, is provided in front of the base member 120. A guide receiving portion 131a extending in the left-right direction is formed in the guide portion 131. As shown in FIG5, the guide receiving portion 131a is formed as a plate protruding from the inner wall of the front and rear sides of the hole-shaped guide portion 131, with its lower surface being a flat, continuous surface with the base member 120, and its upper surface forming a flat guide surface. A guide rod 132 extends in the left-right direction between the front and rear guide receiving portions 131a. A slider 133 is provided in the guide section 131 of the pressure sensor switching device 130. The slider 133 is formed in a slightly T-shape in the cross-sectional view in the front-rear direction (cross-sectional view of FIG. 5). A sleeve 133a and a guide rod 132 are provided in the center of the slider 133 in the front-rear direction. In addition, slider members 133b are provided on the lower surface of the portion extending in the front-rear direction of the slider 133 (corresponding to the crossbar of the T-shape). As shown in Figure 6, the sliding member 133b is held on the retainer 133b1 by a plurality of ball bearings 133b2 rotatably around an axis. The axes of the plurality of ball bearings 133b2 are arranged orthogonally to the direction of movement of the sliding member 133 (the direction in which the guide rod 132 extends). The retainer 133b1 is fixed to the T-shaped body of the sliding member 133. The plurality of ball bearings 133b2 of each sliding member 133b of the sliding member 133 are mounted on guide receiving portions 131a at the front and rear of the guide portion 131. Thus, the sliding member 133 is configured to move left and right along the guide portion 131. As shown in Figures 2 to 4, a motor 134 can be installed on the base member 120 on the front side of the slider 133. The motor 134 is configured such that its output shaft faces forward and backward. A pinion 134a can be provided on the output shaft of the motor 134. The pinion 134a meshes with a rack 133d provided on the upper surface of the slider 133. An encoder 134b can be installed on the motor 134. The motor 134 drives the slider 133 in the left and right directions. As shown in Figures 2 and 3, a positioning member 133c is provided on the upper surface of the rear side of the slider 133. On the other hand, at the edge of the hole of the guide portion 131 in the base member 120, and corresponding to the position of the positioning member 133c, two limiting switches are provided, with a first LS 135a on the left and a second LS 135b on the right. On the surface of the positioning member 133c facing the first LS 135a and the second LS 135b, a V-shaped groove is provided extending in the vertical direction. When the slider 133 is on the right, the V-groove of the positioning member 133c engages with the detection part (the pin protruding from the second LS 135b) of the second LS 135b, activating the second LS 135b and detecting that the slider 133 is in the right position (the position in Figures 2 and 3). Similarly, when the slider 133 is on the left, the first LS 135a detects that the slider 133 is in the left position. Furthermore, on the front side of the left and right ends of the guide part 131 (the left and right sides of the motor 134), light sensors 135 integrated with the light-emitting / light-receiving part are respectively arranged. Detection plates 133d1, which are installed and protrude from the left and right ends of the rack 133d, are inserted into the light sensors 135, enabling the detection of over-limit operation of the slider 133 in the left and right directions. The slider 133 is configured to connect the first pressure sensor 141 and the second pressure sensor 142. Specifically, the first pressure sensor 141, located on the right side of the pressure sensor switching device 130, is connected to the slider 133 via a first connecting block 143 located on the lower surface of the slider 133. Similarly, the second pressure sensor 142, located on the left side of the pressure sensor switching device 130, is connected to the slider 133 via a second connecting block 144 located on the lower surface of the slider 133. Figure 5 illustrates the state in which the second pressure sensor 142 is connected to the slider 133 via the second connecting block 144. At the end of the first pressure sensor 141 on the front side, there is a rod-shaped first pressure head connecting member 141a extending downward. Similarly, at the end of the second pressure sensor 142 on the front side, there is a rod-shaped second pressure head connecting member 142a extending downward. Here, the first pressure sensor 141 is a cantilever beam pressure sensor that corresponds to a relatively large test load (e.g., tens to hundreds of gf). The second pressure sensor 142 is a cantilever beam pressure sensor that corresponds to a relatively small test load (e.g., several gf). The first pressure head connecting member 141a and the second pressure head connecting member 142a are configured to connect with the pressure head 32 when the pressure head 32 of the rotary table device 30 in FIG. 1 is located at the axis 20a of the sample stage device 20. Specifically, when the rotary table device 30 selects the pressure head 32, when the slide 133 is located on the left side and the axis of the first pressure head connecting member 141a is aligned with the axis 20a, the first pressure head connecting member 141a abuts against the movable shaft (not shown, the member connected to the pressure head 32) of the pressure head unit 320 (refer to FIG. 1) equipped with the pressure head 32 to form a connectable state, while the second pressure head connecting member 142a is not connected to the pressure head 32. Similarly, when the slider 133 is located on the right side (as shown in Figures 2 to 4) and the axis of the second pressure head connecting member 142a is aligned with the axis 20a, the second pressure head connecting member 142a abuts against the movable shaft of the pressure head unit 320 equipped with the pressure head 32 to form a connectable state, while the first pressure head connecting member 141a is not connected to the pressure head 32. In the slider 133, by providing a first pressure sensor 141 with a first pressure head connecting member 141a and a second pressure sensor 142 with a second pressure head connecting member 142a, the pressure sensor switching device 130 can be miniaturized as a whole. The hardness testing machine 10 thus formed is used to perform the following hardness measurement. First, a sample is placed on the worktable (not shown) of the sample stage device 20, and the sample stage device 20 is manually raised to the vertical stroke range of the indenter 32 (that is, the stroke range of the base member 120) using a handle (not shown). Then, the objective lens 33 is aligned with the axis 20a to focus. Next, the required pressure head 32 is set on the axis 20a. Furthermore, by means of the pressure sensor switching device 130 of the load unit 100, the pressure head connecting member (first pressure head connecting member 141a or second pressure head connecting member 142a) of the pressure sensor (first pressure sensor 141 or second pressure sensor 142) suitable for the set test load is set on the axis 20a, so that the pressure head 32 and the pressure head connecting member are connected (the movable shaft connected to the pressure head can abut against the pressure head connecting member). Thus, after completing the preparation for the hardness test, the motor 110 is started and the base member 120 is lowered. At this time, the descent speed is accelerated until the tip of the indenter 32 is about to contact the sample. When the tip of the indenter 32 contacts the sample and is in a state of applied load (the state of performing the hardness test), the motor 110 controls the indenter 32 to descend at the speed and holding time specified by the prescribed hardness test method via a control device not shown. The action of the indenter 32 indenting the sample (that is, driving the motor 110 to lower the base member 120, and stopping the action of the base member 120 after a predetermined holding time) is controlled by a detection value, which is determined by the load applied to the indenter 32 by a pressure sensor (first pressure sensor 141 or second pressure sensor 142), which is a corresponding indenter connecting member provided on the axis 20a. After the hardness test is completed, the base component 120 is raised by the motor 110 to move the sample away from the indenter 32. In the hardness testing machine 10, depending on the load selected or set in the hardness test, for example, the first pressure sensor 141 is selected when the load value is in a higher range, and the second pressure sensor 142 is selected when the load value is in a lower range. In this way, a hardness test corresponding to a wide range of load settings can be performed using one hardness testing machine 10. [Second Embodiment] Next, the second embodiment of the present invention will be described with reference to FIGS. 7 to 9. In the load-bearing unit 100A of this embodiment, the left and right slide guide seats 122 in the load-bearing unit 100 of the first embodiment are replaced by guide posts 125. Furthermore, the load-bearing unit 100A of this embodiment is constructed such that the slide member 133b, which serves as the guide mechanism for the slide 133 in the load-bearing unit 100 of the first embodiment and has a slide member 133b1 and a ball bearing 133b2, is replaced by a crossed roller guide 155. In the following description, components that are the same as or equivalent to those in the load-bearing unit 100 of the first embodiment are marked with the same reference numerals, and the description may be simplified or omitted. Guide posts 125 are fixed and provided on the left and right sides of the front side of the fixed plate 101. The base member 120 is supported on the fixed plate 101 by means of the two front guide posts 125 and the two rear guide posts 121, which can be raised and lowered freely. A plate-shaped connecting plate 145 is provided on the lower surface of the slider 133. The connecting plate 145 is configured to protrude from the front end of the base member 120. A first connecting block 143 and a second connecting block 144 are fixed to the lower surface of the connecting plate 145. A first pressure sensor 141 is fixed in the first connecting block 143. A second pressure sensor 142 is fixed in the second connecting block 144. Furthermore, as shown in Figure 8, a linear guide 150 is provided between the lower surface of the base member 120 and the upper surface of the connecting plate 145 to guide the slider 133 in the left-right direction. Two movable members 151 of the linear guide 150 are fixed to the upper surface of the connecting plate 145. In the linear guide 150, a track 152 that engages with the movable members 151 is provided on the lower surface of the base member 120. Furthermore, as shown in FIG9, in the guide section 131, cross roller guides 155 are provided on the front and rear sides of the slide member 133. The cross roller guide 155 includes a roller cage 155a, which is used to hold the cylindrical rollers 155b by changing the orientation of their axial directions differently. The roller cage 155a is sandwiched between the movable member 156 and the fixed member 157. Accordingly, the movable member 156 and the fixed member 157 of the cross roller guide 155 can move linearly relative to each other. Movable members 156 of cross roller guides 155 are fixed to the front and rear sides of the slider 133. Fixing members 157 are provided on the concave section surface 131b of the guide portion 131 of the base member 120, located above the lower surface of the base member 120, on the front and rear sides. Therefore, the slider 133 is held in a position to move in the left-right direction by means of the cross roller guides 155. The cross roller guides 155 are designed to allow the movable members to operate while bearing a specified load. Thus, the pressure sensor switching device 130 of the load unit 100A does not require the guide rod 132 of the load unit 100 in the first embodiment, and can be easily assembled and guided in the left-right direction with high precision. While the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made to implement it. For example, the pressure sensors connected to the indenter are not limited to two types (first pressure sensor 141, second pressure sensor 142), and more than two types may be provided. Furthermore, although the base member 120 is configured to be freely movable relative to the fixed plate 101, it may also be configured to be freely movable relative to the frame of the hardness testing machine 10. The structure for guiding the base member 120 freely in the vertical direction may appropriately select a slide guide or a guide post, or other methods may be used. In addition, even in the structure for guiding the slide 133 in the horizontal direction, in addition to using a ball bearing or a cross roller guide, other forms may be appropriately selected. Also, although the pressure sensor is set to a cantilever beam type, other types of pressure sensors may be used. Furthermore, the drive device is not limited to the motor 110, and other drive devices may be used. 10: Testing machine 11: Base 12: Legs 13: Support column 14: Head 15: Control panel 20: Sample table device 20a: Shaft 30: Rotary seat device 31: Rotary seat plate 31a: Tilting shaft 32: Indenter 33: Objective lens 100: Loading unit 101: Fixing plate 102: Sensor base 103: Photosensor 110: Motor 111: Gearbox 112: Coupling 113: Ball screw mechanism 113a: Ball screw shaft 113b: Nut 120: Base component 121: Guide column 122: Sliding guide seat 123: Detection component 125: Guide column 130: Pressure sensor switching device 131: Guide part 131a: Guide receiving part 132: Guide rod 13 3: Sliding component 133a: Sleeve 133b: Sliding component 133b1: Holder 133b2: Ball bearing 133c: Positioning component 133d: Rack 133d1: Detection plate 134: Motor 134a: Pinion 134b: Encoder 135: Light sensor 141: First pressure sensor 141a: First pressure head connecting component 142: Second pressure sensor 142a: Second pressure head connecting component 143: First connecting block 144: Second connecting block 145: Connecting plate 150: Linear guide 151, 156: Movable component 152: Track 155: Crossed roller guide 155a: Roller retainer 155b: Roller 157: Fixed component 320: Pressure head unit [Figure 1] is a cross-sectional view showing the hardness testing machine according to the first embodiment of the present invention. [Figure 2] is a perspective view of the load-bearing unit of the hardness testing machine according to the first embodiment of the present invention, viewed from the upper front. [Figure 3] is a perspective view of the load-bearing unit of the hardness testing machine according to the first embodiment of the present invention, viewed from the upper rear. [Figure 4] is a perspective view of the load-bearing unit of the hardness testing machine according to the first embodiment of the present invention, viewed from the left rear. [Figure 5] is a VV cross-sectional view of Figure 2 showing the load-bearing unit of the hardness testing machine according to the first embodiment of the present invention, omitting the fixing plate and the motor, which is a drive device. [Figure 6] is a bottom view of the slider of the load-bearing unit of the hardness testing machine according to the first embodiment of the present invention. [Figure 7] is a perspective view of the load-bearing unit of the hardness testing machine according to the second embodiment of the present invention, viewed from the upper front. [Figure 8] is an oblique view from the front left side showing the load-bearing unit of the hardness testing machine according to the second embodiment of the present invention. [Figure 9] is a plan view of the periphery of the slide of the load-bearing unit of the hardness testing machine according to the second embodiment of the present invention, viewed from the lower surface of the base member, omitting the fixing plate and the like. 10: Testing machine 11: Base 12: Feet 13: Support column 14: Head 15: Control Panel 20: Sample Platform Device 20a: Axis 30: Rotary seat device 31: Rotary Seat 31a: Inclined axis 32: Pressure head 33: Objective lens 100: Load Unit 110: Motor 111: Gearbox 120: Base Components 130: Pressure sensor switching device 134: Motor 141: First pressure sensor 141a: First pressure head connecting component 320: Indenter Unit

Claims

1. A hardness testing machine, characterized by comprising: a base member supported in a freely lifting and lowering manner; a driving device for driving the lifting and lowering action of the base member; and a pressure sensor switching device comprising a first pressure sensor having a first indenter connecting member and a second pressure sensor having a second indenter connecting member, and disposed on the base member such that the first pressure sensor and the second pressure sensor can be switched.

2. The hardness testing machine as described in claim 1, wherein, The pressure sensor switching device is movable along the guide portion formed on the base member and has a slider connecting the first pressure sensor and the second pressure sensor.

3. The hardness testing machine as described in claim 1 or 2, wherein, Both the first pressure sensor and the second pressure sensor are cantilever beam type pressure sensors.

4. A hardness testing machine, characterized in that it has two or more pressure sensors connected to an indenter, and is configured to switch the pressure sensors.

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