Characteristic measuring device

Abstract

To provide a characteristic measuring device capable of maintaining a predetermined preload and smoothly switching a floating mass state and a fixed state.SOLUTION: In a characteristic measuring device 100, a support part 120 includes an air spring 123 and a double fastening mechanism 200 disposed between a middle surface plate 122 and a reaction force part 124, the double fastening mechanism 200 includes a first actuator 210 fixed to the reaction force part 124 and a second actuator 220 fixed to the middle surface plate 122, and the reaction force part 124 is supported in a fixed state while the same is not supported in a floating mass state by the first actuator 210 and the second actuator 220. Accordingly, a conventional problem (variation in a preload) is solved and the floating mass state and the fixed state can be switched smoothly.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention particularly relates to a characteristic measurement apparatus that measures dynamic characteristics and durability under high loads for a test object (such as a vibration isolator or vibration isolation component) for an automobile or the like, after applying a predetermined preload to the test object.

Background Art

[0002] In recent years, in addition to vehicles using conventional gasoline engines, hybrid-type vehicles that utilize the rotational force of an electric motor and electric vehicles (hereinafter referred to as "electric vehicles etc.") have been rapidly spreading. The vibration region of this electric motor is expanding toward the higher frequency band side compared to the vibration region of a conventional reciprocating engine.

[0003] In a characteristic test for a test object used in such electric vehicles etc., generally, assuming the actual vehicle state, after applying a predetermined load (hereinafter referred to as "preload") to the test object, it is necessary to measure the load generated by vibration (displacement, acceleration, etc.) input from the outside.

[0004] For example, Patent Document 1 (particularly, refer to FIGS. 2 and 6) describes a characteristic measurement apparatus (hereinafter referred to as "conventional characteristic measurement apparatus") that includes a base having a vibrator, a measurement unit that measures the characteristics of a test object with a load detector, and a support unit that is placed on the base and supports a reaction force unit that functions as a weight via an air spring and a fastening mechanism. This characteristic measurement apparatus performs a process of adjusting the distance between a pair of mounting jigs before measurement, while sandwiching the test object from above and below by the pair of mounting jigs fixed to the base and the support unit respectively, applying a predetermined preload to the test object, and then applying vibration to the test object by the vibrator to measure the characteristic values of the test object.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] As shown in Figure 5, in conventional characteristic measurement devices, the support section 620 had to be switched between a state in which the reaction section 624 is supported by an air spring 623 relative to the central platen 622 (hereinafter referred to as the "floating mass state") (see Figure 5(a)) and a state in which the reaction section 624 is fastened and fixed to the central platen 622 by a fastening mechanism 700 (hereinafter referred to as the "fixed state") (see Figure 5(b)) in order to accommodate the wide range of vibration frequencies input by the vibrator during characteristic testing. As a result, the fixed state is used when the input vibration frequency is approximately 100 to 150 Hz or less, and the floating mass state is used from 150 Hz to several kHz.

[0007] Specifically, the support section 620 in a conventional characteristic measuring device includes a sealed air spring 623, a stopper 625, and a fastening mechanism 700 between the intermediate platen 622 and the reaction force section 624. The fastening mechanism 700 includes an actuator 710 fixed to the lower surface of the reaction force section 624 and a locking member 720 fixed to the upper surface of the intermediate platen 622. The actuator 710 includes a cylinder 711 fixed to the lower surface of the reaction force section 624 and a movable section 712 having a lower enlarged diameter section 712a and an upper enlarged diameter section 712b. Here, the lower enlarged diameter section 712a of the movable section 712 can be locked with the locking member 720, while the upper enlarged diameter section 712b of the movable section 712 is housed in the cylinder 711.

[0008] First, when transitioning from the fixed state to the floating mass state (from Figure 5(b) to Figure 5(a)), driving oil is supplied to the upper sealed space C1 defined by the cylinder 711 and the upper surface of the upper enlarged diameter portion 712b, causing the movable portion 712 to move downward (see black arrow A1 in Figure 5(a)), and releasing the engagement between the lower enlarged diameter portion 712a and the locking member 720. This generates a restoring force in the compressed air spring 623, causing the reaction force portion 624 to move upward (see white arrow B1 in Figure 5(a)).

[0009] Next, when transitioning from the floating mass state to the fixed state (from Figure 5(a) to Figure 5(b)), driving oil is supplied to the lower sealed space C2 defined by the cylinder 711 and the lower surface of the upper enlarged diameter portion 712b, causing the movable portion 712 to move upward (see black arrow A2 in Figure 5(b)), and the lower enlarged diameter portion 712a to engage with the locking member 720. As a result, the actuator 710 compresses the air spring 623 and moves the reaction force portion 624 downward until it contacts the stopper 625 (see white arrow B2 in Figure 5(b)).

[0010] Thus, when switching between the floating mass state and the fixed state, the height position of the reaction force section 624 relative to the central platen 622 fluctuated. In addition, in the fixed state (see Figure 5(b)), the air spring 623 was compressed further downward by the actuator 710 compared to the floating mass state (see Figure 5(a)), making it easier for air to leak from the air spring 623 to the outside. As a result, the positional fluctuation of the reaction force section 624 that occurred when switching from the fixed state to the floating mass state was not reproducible and did not always occur in the same way. Due to this positional fluctuation of the reaction force section 624, the distance between the pair of mounting fixtures that applied a predetermined preload to the test object also fluctuated, resulting in a problem where the preload on the test object fluctuated significantly (hereinafter referred to as "conventional problem (preload fluctuation)").

[0011] To solve this conventional problem (preload fluctuation), it was necessary to adjust the distance between the pair of mounting fixtures that support the test object from above and below each time the floating mass state was switched to the fixed state, which resulted in wasted time and effort.

[0012] The objective of the present invention is to provide a characteristic measuring device that can smoothly switch between a floating mass state and a fixed state while maintaining a predetermined preload. [Means for solving the problem]

[0013] To solve the above problems, the characteristic measuring device comprises a base, a support portion placed on the upper part of the base, and a measuring portion disposed between the base and the support portion for attaching the object to be tested, wherein the support portion comprises a neutral plate fixed to the base, a reaction force portion functioning as a weight, and an air spring and a double fastening mechanism disposed between the neutral plate and the reaction force portion, respectively, wherein the air spring and the double fastening mechanism support the reaction force portion without changing its height in both floating mass and fixed states in order to maintain a predetermined preload on the object to be tested, and the double fastening mechanism comprises a first actuator fixed to the reaction force portion and a second actuator fixed to the neutral plate, wherein the reaction force portion is not supported by the first actuator and the second actuator in the floating mass state, and is supported by the first actuator and the second actuator in the fixed state.

[0014] Furthermore, in the above-described characteristic measuring device, the first actuator may be provided with a first movable part that can move toward and away from the lower surface of the reaction force portion, and the second actuator may be provided with a second movable part that passes through the reaction force portion and the first movable part and has an engaging part that can move toward and away from the lower end of the first movable part, wherein in the floating mass state, the upper and lower ends of the first movable part are spaced apart in the axial direction from the reaction force portion and the second movable part, respectively, and in the fixed state, the upper and lower ends of the first movable part are in contact with the reaction force portion and the second movable part, respectively.

[0015] Furthermore, in the above-described characteristic measuring device, the air spring and the double fastening mechanism support the reaction force portion without changing its height in the temporary fixed state between the floating mass state and the fixed state, and the reaction force portion may be supported only by the first actuator in the temporary fixed state.

[0016] Furthermore, in the above-described characteristic measuring device, the first actuator is provided with a first movable part that can move toward and away from the lower surface of the reaction force portion, and the second actuator is provided with a second movable part that passes through the reaction force portion and the first movable part and has a movable engaging part at the lower end of the first movable part, and in the temporary fixed state, the upper end of the first movable part is brought into contact with the reaction force portion and the lower end of the first movable part is separated from the second movable part, thereby supporting the reaction force portion with respect to the neutral platen without changing the height of the reaction force portion.

[0017] Furthermore, the above-described characteristic measuring device may further include a displacement detector that measures the displacement of the reaction force section, at least in the floating mass state, and a reaction force section height holding means that controls the supply pressure to the air spring based on the displacement signal from the displacement detector. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a characteristic measuring device that can smoothly switch between a floating mass state and a fixed state while maintaining a predetermined preload. [Brief explanation of the drawing]

[0019] [Figure 1] This is a schematic diagram showing an example of a characteristic measuring device according to an embodiment of the present invention, where (a) is a front view including a partial cross-section, and (b) is a top view. [Figure 2] Figure 1 is an enlarged cross-sectional view of the double fastening mechanism. [Figure 3] Figure 2 illustrates the operating states of the double fastening mechanism, with (a) representing the floating mass state, (b) representing the temporary fixed state, and (c) representing the fixed state. [Figure 4] This figure illustrates the means for maintaining the height of the reaction force section in the characteristic measurement device shown in Figure 1. [Figure 5] These are enlarged cross-sectional views of a fastening mechanism and air spring used in conventional characteristic measuring devices, where (a) represents the floating mass state and (b) represents the fixed state.

Best Mode for Carrying Out the Invention

[0020] Embodiments of the present invention will be described in detail with reference to FIGS. 1 to 4. However, the present invention is not limited to the aspects of this embodiment.

[0021] <Regarding Terms> In the descriptions of this specification and the claims, "upper" and "lower" correspond to the upper and lower in FIG. 1(a), indicating the relative positional relationship of each member, and not indicating an absolute positional relationship. The "air spring" in the description of the claims indicates the "support air spring" in the description of this specification.

[0022] <Regarding the Characteristic Measuring Device> An example of a characteristic measuring device 100 according to an embodiment of the present invention will be described with reference to FIG. 1. Note that the left side of the characteristic measuring device 100 in the figure is shown as a partial cross-sectional view for the purpose of explanation. This characteristic measuring device 100 is a measuring device for measuring the dynamic properties of vibration isolators for automobiles, etc., as standardized in, for example, SRIS 3503 (Japan Rubber Association Standard).

[0023] The characteristic measuring device 100 includes a base 110, a support portion 120 placed on the upper part of the base 110 and supporting a reaction force portion 124 functioning as a weight in a floating mass state, a fixed state, etc. via a support air spring (air spring) 123 and a double fastening mechanism 200, a measuring portion 130 disposed between the base 110 and the support portion 120, and a control system (not shown). Hereinafter, each configuration of the characteristic measuring device 100 will be described in order.

[0024] <Regarding the Base> The base 110 includes legs 111, a base air spring 112, a base pedestal portion 113, and an electrodynamic shaker 114.

[0025] Four legs 111 are arranged at positions contacting the ground to fix the characteristic measuring device 100 to the ground.

[0026] The base air springs 112 are elastic bodies placed on top of the four legs 111, and four of them are arranged. By providing these base air springs 112, it is possible to prevent vibrations from being transmitted between the ground and the characteristic measuring device 100 during the vibration test.

[0027] The base frame 113 is made of a relatively large metal such as iron, has a roughly square plate shape in plan view, and has an opening 113a in the center that widens in a stepped manner toward the bottom. The base frame 113 is installed via a base air spring 112 so that the upper surface of the base frame 113 is horizontal.

[0028] The electrodynamic vibrator 114 is fixed to the base frame 113 with its upper part housed within the opening 113a of the base frame 113. The electrodynamic vibrator 114 is electrically connected to the control system and drives the electrodynamic vibrator vibration table 134, which is installed on top of the electrodynamic vibrator 114. The electrodynamic vibrator 114, together with the base frame 113, has sufficient mass and, like the base air spring 112, plays a role in preventing vibration transmission.

[0029] In this embodiment, the base 110 has a base air spring 112 positioned between the four legs 111 and the base frame 113, and the lower part of the legs 111 is fixed to the ground. However, it is not limited to this configuration, and for example, the base 110 can be in any form as long as it prevents the transmission of vibrations and can withstand external factors such as earthquakes.

[0030] <Regarding the support structure> The support section 120 comprises a support column 121, a central platen 122, a support section air spring 123, a double fastening mechanism 200, and a reaction force section 124.

[0031] Four support columns 121 are arranged, with their lower parts fixed to the base frame 113 and their upper parts fixed to the central platen 122. In this embodiment, the support columns 121 are extendable and retractable in the axial direction. For example, by extending them in the axial direction, it is possible to house the measuring section 130 in a constant temperature chamber for measurement, and to measure large test objects 132.

[0032] The center platen 122 has a frame shape in plan view and is provided with a through portion 122a in the center. In this center platen 122, double fastening mechanisms 200 are arranged at the corners, and two support air springs 123 are arranged at the sides connecting the corners. In this embodiment, the double fastening mechanisms 200 and support air springs 123 are arranged at the corners and sides of the center platen 122, respectively, but it is not limited to this, and for example, the support air springs 123 and double fastening mechanisms 200 may be arranged at the corners and sides of the center platen 122, respectively.

[0033] The support air spring 123 is an elastic body positioned between the center platen 122 and the reaction force portion 124. The support air spring 123 can create a floating mass state between the base portion 110 and the reaction force portion 124, blocking the transmission of vibrations such as resonance in high-frequency vibration conditions. In this embodiment, for explanatory purposes, an example using eight support air springs 123 is shown, but the system is not limited to this, and any other number of support air springs 123 may be used as long as a floating mass state can be established.

[0034] The double fastening mechanism 200 is positioned between the center plate 122 and the reaction force section 124, and, as will be described in detail later, includes two actuators (see the first actuator 210 and the second actuator 220 in Figure 2). In its fixed state, the double fastening mechanism 200 firmly connects the base frame 113, the support column 121, the center plate 122, and the reaction force section 124, providing high rigidity and enabling measurement of the static spring constant of the test object 132 and measurements at low vibration frequencies of approximately 100-150 Hz or less. In this embodiment, for explanatory purposes, a configuration using four double fastening mechanisms 200 is shown, but the configuration is not limited to this, and other numbers of double fastening mechanisms 200 may be used as long as a fixed state with sufficient bonding rigidity can be constructed. As will be described in detail later, the double fastening mechanism 200 of this embodiment, by driving two actuators, can maintain the height position of the reaction force section 124 without changing it when switching between the floating mass state, the temporarily fixed state, and the fixed state, via the double fastening mechanism 200 and the support air spring 123. This eliminates the conventional problem (fluctuation of preload) and allows for smooth switching between the floating mass state and the fixed state.

[0035] The reaction force section 124 functions as a weight, and its lower part is inserted into the penetration section 122a of the center platen 122. The resonant frequency of this reaction force section 124 needs to be higher than the measurement range being measured, so it is set to a relatively large mass (for example, 1500 kg or more).

[0036] <About the measurement section> The measuring unit 130 comprises a pair of mounting fixtures 131, a test object 132, a load washer 133, and an electrodynamic vibrator vibration table 134.

[0037] The pair of mounting fixtures 131 comprises an upper mounting fixture 131a installed below the reaction force section 124 and a lower mounting fixture 131b installed above the electrodynamic vibrator vibration table 134.

[0038] The test object 132 is a vibration-damping rubber containing a phase element, such as a mass-type vibration-damping rubber or liquid-filled vibration-damping rubber for automobiles. The test object 132 is held between a pair of mounting fixtures 131 for measurement. In this embodiment, the test object 132 was a vibration-damping rubber for automobiles, but it is not limited to this and may be general industrial rubber.

[0039] The load washer 133 is positioned above the test object 132 via the upper mounting fixture 131a. The load washer 133 is a highly rigid piezoelectric element with a fast response speed and a small measurement threshold, and therefore constitutes a dynamic load measuring device for measuring the dynamic load applied to the test object 132.

[0040] The electrodynamic vibrator vibration table 134 is installed on top of the electrodynamic vibrator 114 and is controlled by a control system. The electrodynamic vibrator vibration table 134 has a diaphragm (not shown) and a coil section (not shown) directly connected to it, and an alternating current magnetic field is arranged around it. The electrodynamic vibrator vibration table 134 is driven by applying an alternating current to this coil. In this embodiment, the vibration frequency range of the electrodynamic vibrator 114 is up to 3 kHz, but it is not limited to this, and may be, for example, 3 kHz or higher.

[0041] <About the control system> The control system, although not shown in the diagram, mainly comprises a main control unit and a power amplifier enclosure.

[0042] The main control unit controls the characteristic measuring device 100 and is connected to the power supply and the characteristic measuring device 100 via a starter and control lines. The main control unit mainly includes a main servo controller, a charge amplifier, a vibration exciter control panel, an uninterruptible power supply, and a user interface. The main servo controller receives signals such as dynamic load and displacement from various sensors of the characteristic measuring device 100 and performs various measurements and calculations.

[0043] The power amplifier enclosure is controlled by signals from the exciter control panel of the main control unit, and controls, for example, the operation of the electrodynamic exciter vibration table 134 of the electrodynamic exciter 114 of the characteristic measuring device 100.

[0044] <Detailed configuration of the double fastening mechanism> The detailed configuration of the double fastening mechanism 200 will be explained using Figure 2. Note that the double fastening mechanism 200 shown in the figure is partially a cross-sectional view for illustrative purposes.

[0045] The double fastening mechanism 200 comprises a first actuator 210 and a second actuator 220.

[0046] <Regarding the first actuator> The first actuator 210 includes a first cylinder 211, a first movable part 212 housed in the first cylinder 211, a first hydraulic supply and discharge path 213, a first biasing means 214 that biases the first movable part 212 downward, and a fixing member 215 fixed to the lower end of the first movable part 212 and supporting the area below the first biasing means 214.

[0047] The first cylinder 211 is a hollow cylindrical member fixed to the upper part of the center platen 122, and has a stepped inner circumferential surface that penetrates along the axis C direction. On this inner circumferential surface, an upper small-diameter portion 211a, a first piston housing portion 211b, a lower guide portion 211c, and a first spring housing portion 211d are continuously formed so as to repeatedly decrease and increase in diameter from top to bottom. In addition, a recess 122b is formed in the center platen 122 so as to be continuous with the inner circumferential surface of the first cylinder 211.

[0048] The first movable part 212 is a hollow cylindrical member housed in the recess 122b of the first cylinder 211 and the center platen 122, and has a through hole 212a that penetrates through the axial direction C with the same diameter, and a stepped outer surface. On this outer surface, the upper shaft portion 212b and the first piston portion 212c are progressively widened in diameter from top to bottom, while the stepped portion 212d, the lower shaft portion 212e, and the spring contact portion 212f are progressively narrowed in diameter.

[0049] Here, we will describe the arrangement relationship between the first movable part 212 and the first cylinder 211. First, a radial gap is formed between the upper shaft portion 212b and the upper small-diameter portion 211a. Also, between the stepped portion 212d and the first piston housing portion 211b, and between the spring contact portion 212f and the first spring housing portion 211d, predetermined radial gaps are formed to define the space for housing the first sealed space S1 and the first biasing means 214, respectively, although the details will be described later. Furthermore, very small gaps are formed between the first piston portion 212c and the first piston housing portion 211b, and between the lower shaft portion 212e and the lower guide portion 211c, in order to allow relative sliding in the direction of axis C.

[0050] The first hydraulic supply and discharge path 213 penetrates from the outer circumferential surface to the inner circumferential surface of the first cylinder 211, and by switching between a connected state that allows supply and discharge or a disconnected state, it is possible to supply, discharge, and maintain drive fluid in the first sealed space S1 defined by the first cylinder 211 and the first movable part 212.

[0051] Furthermore, as shown in Figure 2, the first sealed space S1 never becomes zero and is always fluidly connected to the first hydraulic supply and discharge path 213, so that hydraulic pressure can be smoothly supplied to and discharged from the first sealed space S1. By controlling the hydraulic pressure of the drive fluid via this first hydraulic supply and discharge path 213, the first movable part 212 is moved to a desired position in the direction of axis C, and the first movable part 212 can be moved toward and away from the reaction force part 124.

[0052] The first biasing means 214 is made of, for example, a disc spring and is housed in the first spring housing portion 211d and the recess 122b of the center platen 122. It is clamped in the axial direction C by the lower guide portion 211c and the fixing member 215 fixed to the lower end of the first movable portion 212. As a result, the first movable portion 212 is constantly biased downward by the first biasing means 214. Therefore, when the first hydraulic supply and discharge path 213 is in a dischargeable communication state, the drive fluid is discharged from the first sealed space S1, causing the first movable portion 212 to be positioned at a position separated downward from the reaction force portion 124. On the other hand, when the first hydraulic supply and discharge path 213 is in a state of open supply, the hydraulic pressure of the drive fluid is supplied to the first sealed space S1 such that it overcomes the resultant force of the biasing force of the first biasing means 214 and the weight of the first movable part 212, thereby positioning the first movable part 212 in contact with the reaction force part 124.

[0053] <Regarding the second actuator> The second actuator 220 includes a second cylinder 221, a second movable part 222 housed in the second cylinder 221, a second hydraulic supply and discharge path 223, and a second biasing means 224 for biasing the second movable part 222 downward.

[0054] The second cylinder 221 is a hollow cylindrical member fixed to the upper part of the flange 124a of the reaction force section 124. It has a stepped inner circumferential surface that penetrates along the axis C direction. On this inner circumferential surface, a communication hole 221a, a second spring housing section 221b, and a second piston housing section 221c are formed in succession from top to bottom, with the diameter of the communication hole 221a, the second spring housing section 221b, and the second piston housing section 221c increasing in diameter sequentially, while the lower end guide section 221d decreases in diameter. In addition, an insertion hole 124b is formed in the flange 124a of the reaction force section 124, extending along the axis C direction with the same diameter, so as to be continuous with the inner circumferential surface of the second cylinder 221.

[0055] The second movable part 222 is a solid cylindrical member that extends along the axis C direction with the same diameter and has a shaft portion 222a that is inserted into the insertion hole 124b of the flange portion 124a and the through hole 212a of the first movable part 212, respectively; a second piston portion 222b that is provided at the upper end of the shaft portion 222a with an enlarged diameter and is housed in the second cylinder 221; and an engaging portion 222c that is formed at the lower end of the shaft portion 222a with an enlarged diameter and is housed in the recess 122b of the center plate 122.

[0056] Here, we will describe the arrangement of the second movable part 222, the second cylinder 221, the flange 124a, and the first movable part 212. First, a very small gap is formed between the second piston part 222b and the second piston housing part 221c, and between the shaft part 222a and the lower end guide part 221d, in order to allow relative sliding in the direction of axis C. In addition, a gap is formed in the radial direction between the shaft part 222a and the insertion hole 124b, and between the shaft part 222a and the through hole 212a.

[0057] The second hydraulic supply and discharge path 223 penetrates from the outer circumferential surface to the inner circumferential surface of the second cylinder 221, and by switching between a connected state that allows supply and discharge and a disconnected state, it is possible to supply, discharge, and maintain the drive fluid in the second sealed space S2 defined by the second cylinder 221 and the second movable part 222. By controlling the hydraulic pressure of the drive fluid through this second hydraulic supply and discharge path 223, the second movable part 222 is moved to a desired position in the direction of axis C, and the second movable part 222 is made able to move toward and away from the first movable part 212.

[0058] The second biasing means 224 consists of, for example, a coil spring and is housed in the second cylinder 221. It is clamped in the axial direction C by the second spring housing portion 221b and the spring receiving portion 222b1 provided on the second piston portion 222b. As a result, the second movable portion 222 is constantly biased downward by the second biasing means 224. Therefore, when the second hydraulic supply and discharge path 223 is in a dischargeable communication state, the drive fluid is discharged from the second sealed space S2, causing the engaging portion 222c of the second movable portion 222 to be positioned at a position separated downward from the fixed member 215. On the other hand, when the second hydraulic supply and discharge path 223 is in a state of open supply, the hydraulic pressure of the drive fluid is supplied to the second sealed space S2 such that it overcomes the combined force of the biasing force of the second biasing means 224 and the weight of the second movable part 222, thereby positioning the engaging portion 222c of the second movable part 222 in contact with the fixed member 215.

[0059] <Regarding the operation status of the double fastening mechanism> The operating state of the double fastening mechanism 200 will be explained using Figure 3. Note that the reference height h0 in the figure indicates the height of the lower surface of the flange portion 124a of the reaction force portion 124, and shows that there is no vertical movement of the reaction force portion 124 in any of the floating mass state, temporary fixed state, or fixed state.

[0060] <When transitioning from floating mass state to temporarily fixed state to fixed state> First, the double fastening mechanism 200 in the floating mass state will be described. As shown in Figure 3(a), the first actuator 210 is configured so that the drive oil from the first sealed space S1 can be discharged via the first hydraulic supply and discharge path 213. Therefore, the first movable part 212 is biased downward by the first biasing means 214, and the lower surface of the stepped portion 212d of the first movable part 212 is held in a position where it contacts the upper surface of the lower guide portion 211c of the first cylinder 211. Similarly, the second actuator 220 is configured so that the drive oil from the second sealed space S2 can be discharged via the second hydraulic supply and discharge path 223. Therefore, the second movable part 222 is biased downward by the second biasing means 224, and the lower surface of the second piston portion 222b of the second movable part 222 is held in a position where it contacts the upper surface of the lower end guide portion 221d of the second cylinder 221.

[0061] As a result, the first movable part 212 is separated from the flange portion 124a of the reaction force portion 124 by a distance l1 in the direction of axis C, and the first movable part 212 is separated from the engaging portion 222c of the second movable part 222 by a distance l2 in the direction of axis C. Therefore, the reaction force portion 124 is not supported by the first actuator 210 and the second actuator 220 and is in a floating mass state. In this floating mass state, the first hydraulic supply and discharge path 213 and the second hydraulic supply and discharge path 223 are in a state where drive oil can be discharged or are not in communication state.

[0062] Next, the double fastening mechanism 200 that transitions from a floating mass state to a temporarily fixed state will be described. As shown in Figure 3(b), the first actuator 210 is supplied with drive oil to the first sealed space S1 via the first hydraulic supply and discharge path 213 (see arrow d1 in the figure), and the first movable part 212 moves upward against the first biasing means 214 (see arrow M1 in the figure). Subsequently, the supply of drive oil is stopped when the first movable part 212 comes into contact with the flange portion 124a of the reaction force portion 124. At this time, the amount of drive oil supplied to the first actuator 210 is controlled so that the first movable part 212 makes a soft landing against the reaction force portion 124, so that the reaction force portion 124 does not fluctuate upward before and after contact. On the other hand, since the second actuator 220 is not supplied with drive oil to the second sealed space S2 via the second hydraulic supply and discharge path 223, the second movable part 222 does not move.

[0063] As a result, the reaction force section 124 is in a temporarily fixed state, supported from below only by the first actuator 210. In this temporarily fixed state, the first hydraulic supply and discharge path 213 is not in communication, while the second hydraulic supply and discharge path 223 is either in a state where drive oil can be discharged or is not in communication.

[0064] Next, we will describe the double fastening mechanism 200 that transitions from a temporary fixed state to a fixed state. As shown in Figure 3(c), the first actuator 210 does not receive drive oil from the first sealed space S1 via the first hydraulic supply / discharge path 213, so the first movable part 212 does not move. On the other hand, the second actuator 220 receives drive oil from the second sealed space S2 via the second hydraulic supply / discharge path 223 (see arrow d2 in the figure), and the second movable part 222 moves upward against the second biasing means 224 (see arrow M2 in the figure). Subsequently, the supply of drive oil is stopped when the engaging portion 222c of the second movable part 222 contacts the fixed portion 121e of the first movable part 212. In this case, the second movable part 222 is fixed to the reaction force part 124 in the direction of axis C via the first movable part 212, thereby firmly fastening and fixing the central platen 122 to which the first actuator 210 is fixed and the reaction force part 124 to which the second actuator 220 is fixed.

[0065] As a result, the reaction force section 124 is firmly fastened and fixed from below by the first actuator 210 and the second actuator 220. In this fixed state, the first hydraulic supply and discharge path 213 and the second hydraulic supply and discharge path 223 are not in communication.

[0066] <When transitioning in the order of fixed state, temporarily fixed state, and floating mass state> The explanation regarding the transition from the floating mass state to the temporarily fixed state and then to the fixed state of the double fastening mechanism 200, as described above, will be omitted as it would be redundant.

[0067] First, the double fastening mechanism 200, which transitions from a fixed state to a temporarily fixed state, will be described. As shown in Figure 3(c), in the first actuator 210, the first hydraulic supply and discharge path 213 is not in communication, so the first movable part 212 does not move. On the other hand, in the second actuator 220, the drive oil in the second sealed space S2 can be discharged via the second hydraulic supply and discharge path 223 (see arrow d3 in the figure), so the second movable part 222 is biased by the second biasing means 224 and moves downward (see arrow M3 in the figure). Subsequently, the discharge of drive oil is stopped when the engaging part 222c of the second movable part 222 is separated from the first movable part 212.

[0068] Next, the double fastening mechanism 200 that transitions from a temporarily fixed state to a floating mass state will be described. As shown in Figure 3(b), the first actuator 210 is set to a state where the drive oil from the first sealed space S1 can be discharged via the first hydraulic supply and discharge path 213 (see arrow d4 in the figure), so the first movable part 212 is biased by the first biasing means 214 and moves downward (see arrow M4 in the figure). Subsequently, the discharge of the drive oil is stopped when the first movable part 212 is at a position separated from the flange portion 124a of the reaction force portion 124.

[0069] Furthermore, the double fastening mechanism 200 in the floating mass state will be described. As shown in Figure 3(a), since the first actuator 210 and the second actuator 220 are not supplied with driving oil, the first movable part 212 and the second movable part 222 do not move.

[0070] Thus, in the temporary and fixed states, the reaction force unit 124 is supported and fixed to the central platen 122 while maintaining the height position of the reaction force unit 124 in the floating mass state. Therefore, when the floating mass state is returned, the reaction force unit 124 does not move in the vertical direction.

[0071] As described above, the double fastening mechanism 200 of this embodiment can maintain the height position of the reaction force section 124 (see reference height h0 in Figure 3) without changing it when switching between the floating mass state, the temporarily fixed state, and the fixed state, by driving the first actuator 210 and the second actuator 220, via the double fastening mechanism 200 and the support air spring 123. This eliminates the conventional problem (preload fluctuation) and allows for smooth switching between the floating mass state and the fixed state. Furthermore, since the vertical compressive force applied to the support air spring 123 of this embodiment does not change in the floating mass state, the temporarily fixed state, and the fixed state, it is possible to suppress the rapid increase in the internal pressure of the support air spring 123 and the resulting air leakage when switching to each state. Furthermore, unlike the conventional fastening mechanism 700 (see Figure 5), the double fastening mechanism 200 in this embodiment employs a temporary fixed state. By gradually increasing the supporting force on the reaction force portion 124 from an unsupported floating mass state to a temporary fixed state where it is supported by a soft landing from below, and then to a fixed state where it is firmly fastened and fixed from below, or conversely, gradually decreasing the supporting force from a fixed state to a temporary fixed state and then to a floating mass state, it is possible to suppress sudden fluctuations in the reaction force portion 124.

[0072] <Regarding the means for maintaining the height of the reaction force section> As described above, in the characteristic measuring device 100 of this embodiment, by adopting a double fastening mechanism 200 instead of the conventional fastening mechanism 700 (see Figures 5(a) and (b)), the conventional problem (preload fluctuation) is resolved without changing the height position of the reaction force part 124, and it is possible to smoothly switch between the floating mass state and the fixed state. Furthermore, the inventors conducted further investigations into the vertical behavior of the reaction force part 124 when the double fastening mechanism 200 is adopted. As a result, they found that, in particular, when switching from the fixed state (see Figure 3(c)) to the floating mass state (see Figure 3(a)), the height position of the reaction force part 124 may change slightly below the desired reference height h0, and that this is due to the airtightness of the support air spring 123. Specifically, in the fixed state, the support air spring 123 is compressed for a long period of time, causing a small amount of air leakage. Subsequently, it enters a floating mass state, which can occur because the support air spring 123 supports the reaction force part 124 on its own.

[0073] To solve this new problem (hereinafter referred to as "fluctuation of the reaction force in the floating mass state"), as shown in Figure 4, a reaction force height holding means 300 is adopted in addition to the double fastening mechanism 200 in the support part 120. Here, for the sake of explanation, Figure 4 shows one reaction force height holding means 300 provided for one support part air spring 123, but similar reaction force height holding means 300 are also provided for the other support part air springs 123.

[0074] The reaction force height holding means 300 comprises a proportional pressure control valve 310, a pressure supply source 320, a silencer 330, a displacement detector 340, and a PID control unit 350. The configurations of each component of the reaction force height holding means 300 will be described in order below.

[0075] The proportional pressure control valve 310 continuously adjusts the supply pressure PS according to an external control value u. One end is fluid-connected to a pressure supply source 320 that supplies compressed air at high pressure (0.4 MPa or higher) and a silencer 330 that discharges the compressed air into the external environment without noise. The other end is fluid-connected to a support air spring 123.

[0076] The displacement detector 340 is a wire-type displacement meter equipped with a wire section 340a. The upper end of this wire section 340a is fixed to the flange section 124a of the reaction force section 124, and the wire section 340a outputs a displacement position H1, which is a displacement signal corresponding to expansion and contraction. In this embodiment, the displacement detector 340 is a contact-type displacement meter, but it is not limited to this, and for example, a non-contact displacement meter (for example, a laser-type displacement meter) may be used.

[0077] The PID control unit 350 combines proportional control, integral control, and differential control. It calculates a control value u from three elements: the error e between the displacement position H1 and the target position Hr, its integral, and its derivative, and controls the supply pressure PS. By controlling the supply pressure PS using this PID control unit 350, the displacement position H1 of the reaction force unit 124 can be stably and quickly brought to the target position Hr while suppressing overshoot.

[0078] <Regarding the operation of the reaction force height holding mechanism> The reaction force height holding means 300 is configured to operate particularly when switching from a temporarily fixed state to a floating mass state, and in the floating mass state, where the height position of the reaction force 124 may fluctuate.

[0079] Here, if the displacement position H1 is lower than the target position Hr, the PID control unit 350 controls the proportional pressure control valve 310 so that the supply pressure PS increases, and as a result the internal pressure of the support air spring 123 rises, and the reaction force part 124 moves upward toward the target position Hr (see the upward arrow in Figure 4). On the other hand, if the displacement position H1 is higher than the target position Hr, the PID control unit 350 controls the proportional pressure control valve 310 so that the supply pressure PS decreases, and as a result the internal pressure of the support air spring 123 decreases, and the reaction force part 124 moves downward toward the target position Hr (see the downward arrow in Figure 4).

[0080] As described above, the reaction force height holding means 300 of this embodiment controls the supply pressure PS to the support air spring 123 when switching from a temporarily fixed state to a floating mass state, and in the floating mass state, thereby enabling the displacement position H1 of the reaction force 124 to reach the target position Hr stably and quickly. This eliminates a new problem (fluctuation of the reaction force in the floating mass state) and allows for smoother switching between the floating mass state and the fixed state.

[0081] In this embodiment, the reaction force height holding means 300 is configured to operate at least in the floating mass state (when switching from the temporary fixed state to the floating mass state, and in the floating mass state), but it is not limited to this, and may be configured to operate at all times (floating mass state, temporary fixed state, and fixed state).

[0082] <Other> The present invention is not limited to the embodiments described above, and can be modified or altered as appropriate without departing from the technical spirit of the present invention.

[0083] 100 Characteristic Measurement Device 110 Base 111 Legs 112 Base air spring 113 Base frame section 114 Electrodynamic Vibrator 120 Support part 121 Post 122 Medium surface plate 122a Penetration 122b Recess 123 Support air spring (air spring) 124 Reaction part 124a Tsuba 124b Through hole 130 Measuring section 131 Pair of mounting fixtures 131a Upper mounting jig 131b Lower mounting jig 132 Test specimen 133 Load Washer 134 Electrodynamic vibrator vibration table 200 Double fastening mechanism 210 First actuator 211 First cylinder 211a Upper end small diameter section 211b First piston housing 211c Lower guide section 211d First spring housing 212 First movable part 212a Through hole 212b Upper shaft part 212c First piston section 212d Step section 212e Lower shaft part 212f Spring contact section 213 First hydraulic supply and discharge path 214 First biasing means 215 Fixing member 220 Second actuator 221 Second cylinder 221a Communication hole 221b Second spring housing 221c Second piston housing 221d Lower end guide section 222 Second movable part 222a Shaft 222b Second piston section 222b1 Spring support 222c Engagement part 223 Second hydraulic supply and discharge path 224 Second biasing means 300 Reaction force height holding means 310 Proportional pressure control valve 320 Pressure supply source 330 Silencer 340 Displacement Detectors 340a Wire section 350 PID Control Unit C axis e error H1 Displacement position Hr target position h0 Reference height l1 Distance between the first movable part and the flange of the reaction part l2 Distance between the engagement portion of the first movable part and the second movable part PS supply pressure S1 First sealed space S2 Second sealed space u control value

Claims

[Claim 1] A characteristic measuring device comprising a reaction force section and an air spring, In a floating mass state in which the air spring independently supports the reaction force portion, the system includes a means for maintaining the height of the reaction force portion to control the supply pressure to the air spring. The aforementioned reaction force height holding means is A pressure supply source that supplies compressed air to the aforementioned air spring, A control valve that adjusts the supply pressure to the air spring, A displacement detector for measuring the displacement of the reaction force portion, Based on the displacement measured by the displacement detector, a control unit controls the control valve, Equipped with, To maintain the height position of the reaction force portion, If the displacement position of the reaction force portion is lower than the target position, the control unit controls the supply pressure to increase. A characteristic measuring device characterized in that, if the displacement position of the reaction force portion is higher than the target position, the control unit controls the supply pressure to be lower.

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