Radio wave shielding structure and chassis dynamometer system

Abstract

A radio wave shielding structure (1) is provided with: an electrically conductive flat belt (3) which is wound around a pair of rollers (2) arranged in parallel below the surface of a metal floor (103), is exposed from an opening (104) formed in the metal floor (103), and on which tires (101, 102) of a vehicle (100) are placed; and a conductive radio wave shielding roller (4) that is disposed between the metal floor (103) and the flat belt (3) at the opening (104), is electrically connected to the metal floor (103), and rotates in conjunction with the movement of the flat belt (3) by coming into contact with the flat belt (3).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an electromagnetic wave shielding structure and a chassis dynamometer system. BACKGROUND

[0002] A chassis dynamometer system is a system for performing a test related to running of a vehicle, for example, measuring a force received by a rotating tire or a peripheral speed of the tire, and the like.

[0003] In a case where a vehicle of a model in which a wheelbase, which is an interval between front wheels and rear wheels, is different becomes a test target, in the conventional chassis dynamometer system, it is necessary to change the interval between the front-wheel roller and the rear-wheel roller according to the wheelbase. In this case, it is necessary to perform a large-scale work of changing the interval between the front-wheel roller and the rear-wheel roller according to the wheelbase after excavating the floor.

[0004] As a prior art for solving the above problem, for example, there is a vehicle running test device described in Patent Literature 1. The vehicle running test device is a chassis dynamometer system provided with a pair of rollers arranged in parallel under a floor and a flat belt wound around the rollers. A difference in the wheelbase of a vehicle is absorbed by a length in the length direction of the flat belt, so that a work of moving the rollers according to the wheelbase is not necessary, and tests of various models can be performed.

[0005] PRIOR ART DOCUMENT

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 2011-162912 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] In a case where an electromagnetic environment compatibility (hereinafter, described as EMC) test is performed by simulating running of a vehicle, it is necessary to arrange the chassis dynamometer system in an electromagnetic wave darkroom. On the other hand, in the electromagnetic wave darkroom, a metal floor is adopted on a floor surface in order to block electromagnetic noise. In a case where the chassis dynamometer system using the flat belt is arranged in such an electromagnetic wave darkroom, it is necessary to form an opening portion in the metal floor surface and expose the flat belt from the opening portion to the electromagnetic wave darkroom. Therefore, the conventional chassis dynamometer system has a problem that electromagnetic noise radiated from a driving portion of the flat belt and electromagnetic noise radiated from a test target device in the electromagnetic wave darkroom can propagate to the inside and outside of the electromagnetic wave darkroom through the opening portion.

[0010] The present disclosure is to solve the above problem, and aims to obtain an electromagnetic wave shielding structure capable of shielding an electromagnetic wave propagated through an opening portion formed in a metal floor surface in a room in which a chassis dynamometer system is arranged.

[0011] Methods for solving problems

[0012] The disclosed electromagnetic shielding structure is an electromagnetic shielding structure for a chassis dynamometer system capable of performing vehicle simulation on a metal floor surface. It comprises: a conductive flat strip wound around a pair of rollers arranged parallel to each other under the metal floor surface, protruding from an opening formed in the metal floor surface to support the vehicle's tires; and a conductive electromagnetic shielding roller disposed between the metal floor and the flat strip at an opening, communicating with the metal floor surface, and rotating in contact with the flat strip as the flat strip moves.

[0013] Invention Effects

[0014] According to this disclosure, the device comprises: a conductive flat strip that exposes from an opening formed in the metal floor surface and carries the vehicle's tires; and a conductive electromagnetic wave shielding roller disposed between the metal floor and the flat strip at the opening, conducting to the metal floor, and rotating in contact with the flat strip as the flat strip moves. Thus, the flat strip becomes at the same potential as the metal floor, and therefore the electromagnetic wave shielding structure of this disclosure can shield electromagnetic waves propagating through the opening formed in the metal floor surface of a room equipped with a chassis dynamometer system. Attached Figure Description

[0015] Figure 1 This is a schematic side view of the chassis dynamometer system of Embodiment 1.

[0016] Figure 2A and Figure 2B This is a schematic diagram illustrating an EMC test of a vehicle performed in an anechoic chamber.

[0017] Figure 3 This is a side view schematically illustrating the radio wave shielding structure of Embodiment 1.

[0018] Figure 4 This is a top view schematically illustrating the radio wave shielding structure of Embodiment 1.

[0019] Figure 5 This is a top view schematically showing a modified example (1) of the radio wave shielding structure of Embodiment 1.

[0020] Figure 6 This is a side view schematically showing a modified example (1) of the radio wave shielding structure of Embodiment 1.

[0021] Figure 7 This is a top view schematically showing a modified example (2) of the radio wave shielding structure of Embodiment 1.

[0022] Figure 8 This is a top view schematically showing a modified example (3) of the radio wave shielding structure of Embodiment 1.

[0023] Figure 9A and Figure 9B This is a side view schematically showing a modified example (4) of the radio wave shielding structure of Embodiment 1.

[0024] Figure 10 This is a schematic side view of the chassis dynamometer system of Embodiment 2.

[0025] Figure 11 This is a side view schematically illustrating the radio wave shielding structure of Embodiment 2.

[0026] Figure 12 This is a top view schematically illustrating the radio wave shielding structure of Embodiment 2.

[0027] Figure 13A and Figure 13B This is a schematic front view of the roller representing the radio wave shielding structure of Embodiment 2.

[0028] Figure 14A and Figure 14B This is a schematic front view showing the radio wave shielding structure of Embodiment 2. Detailed Implementation

[0029] Implementation method 1.

[0030] Figure 1 This is a schematic side view of the chassis dynamometer system 200 according to Embodiment 1. Figure 1 In this system, the chassis dynamometer system 200 is a system capable of performing simulations of the vehicle 100 on the surface of a metal floor 103. For example, the chassis dynamometer system 200 is installed in an anechoic chamber having a metal floor 103. Figure 1 As shown, the chassis dynamometer system 200 has an electromagnetic shielding structure 1 disposed under the metal floor 103.

[0031] The radio wave shielding structure 1 includes a flat belt 3 wound around a pair of rollers 2 and a radio wave shielding roller 4. The pair of rollers 2 are respectively provided for the front wheel tire 101 and the rear wheel tire 102 of the vehicle 100, which is the test vehicle. An opening is formed in the metal floor 103, through which the flat belt 3 wound on the rollers 2 is exposed into the radio wave anechoic chamber.

[0032] In addition, such as Figure 1 As shown, a pair of rollers 2 are arranged parallel to each other below the metal floor 103. Therefore, the flat portion of the flat belt 3 wound on the rollers 2 is approximately parallel to the surface of the metal floor 103. The vehicle 100 is positioned in the anechoic chamber with tires 101 and 102 mounted on the flat portion of the flat belt 3.

[0033] For example, by causing tire 101 to...Figure 1 As indicated by the arrow, the roller 2 rotates in the opposite direction to the tire 101, and the flat belt 3 wound on the roller 2 also rotates. In this way, the chassis dynamometer system 200 can simulate a state close to the actual driving state of the vehicle 100 with the tires 101 and 102 of the vehicle 100 mounted on the flat belt 3.

[0034] In addition, although Figure 1 The illustration is omitted, but a drive control device for rotating the flat belt 3 and even the roller 2 is located below the metal floor 103. Additionally, the vehicle 100 is equipped with a test device for EMC testing. The drive control device and the test device contain electronic circuitry, which could become noise sources generating unwanted electromagnetic waves.

[0035] On the other hand, as described above, an opening is formed in the metal floor 103 of the anechoic chamber to expose the flat strip 3. A gap is required between the flat strip 3 and the opening in the metal floor 103 to avoid obstructing the rotational drive of the flat strip 3. Therefore, electromagnetic noise generated by the aforementioned noise source may propagate into or out of the anechoic chamber through this gap.

[0036] To solve this problem, in the radio wave shielding structure 1, a conductive radio wave shielding roller 4 is provided between the conductive flat strip 3 at the opening of the metal floor 103 and the metal floor 103.

[0037] For example, such as Figure 1 As shown, at the opening of the metal floor 103, the wave shielding roller 4 is disposed on either or both of the portion 104A where the flat strip 3 emerges from under the floor and the portion 104B where it is recessed under the floor.

[0038] The wave shielding roller 4 is connected to the metal floor 103, and the circumferential surface of the roller is in contact with the flat belt 3, so that it rotates along with the movement of the flat belt 3.

[0039] For example, in Figure 1 In the middle, roller 2 rotates clockwise, thereby causing the flat belt 3 to rotate clockwise as well. The radio wave shielding roller 4, which is in contact with the flat belt 3, rotates counterclockwise along with the rotation of the flat belt 3.

[0040] The flat strip 3 has at least a conductive surface, and the electromagnetic shielding roller 4 is a conductive component that is in contact with the metal floor 103. Therefore, through the contact between the electromagnetic shielding roller 4 and the flat strip 3, the flat strip 3 is electrically connected to the metal floor 103 via the electromagnetic shielding roller 4, and becomes at the same potential (ground potential) as the metal floor 103.

[0041] In this way, the flat strip 3 functions as a larger ground plane disposed at the opening formed in the metal floor 103, and thus can shield electromagnetic waves propagating through the opening.

[0042] Furthermore, even when the flat strip 3 rotates, the electromagnetic shielding roller 4 also rotates, thus maintaining contact with the flat strip 3. Therefore, the electromagnetic shielding structure 1 can electrically connect the flat strip 3 to the metal floor 103 regardless of the rotation of the flat strip 3. Moreover, since the electromagnetic shielding roller 4 rotates while in contact with the flat strip 3, it also provides a less deteriorating effect compared to a structure where only the metal sheet contacts the rotating flat strip 3.

[0043] Next, an overview of the EMC test using an anechoic chamber equipped with a chassis dynamometer system 200 will be provided. Figure 2A This is a schematic top view showing an EMC test of vehicle 100 performed in an anechoic chamber 300. Additionally, Figure 2B This is a schematic front view showing an EMC test of a vehicle 100 performed in an anechoic chamber 300. Figure 2A as well as Figure 2B This refers to the anechoic chamber 300 used for EMC measurements of vehicle 100. Furthermore, although in Figure 2A as well as Figure 2B The illustration is omitted, but it is configured in the anechoic chamber 300. Figure 1 The chassis dynamometer system 200 shown is illustrated.

[0044] In EMC measurements, a receiving antenna 302 mounted on antenna mast 301 is used. For example... Figure 2A As shown, the antenna mast 301 is equipped with a receiving antenna 302 at a height of 3m above the floor. The distance D between the receiving antenna 302 and the vehicle 100 is the measurement distance in EMC measurement, which is set to 3m or 10m, etc.

[0045] In EMC testing, for example, a vehicle 100 with its tires mounted on a flat surface 3 is moved to simulate a driving state, while a receiving antenna 302 measures the electromagnetic waves radiated from the vehicle 100 under this condition. The measurement distance D can also be varied during the test. In EMC testing, only the electromagnetic waves radiated from the vehicle 100 are accurately measured; therefore, electromagnetic noise from sources other than the vehicle 100 must be excluded.

[0046] The electromagnetic shielding structure 1 can block electromagnetic noise through the opening formed on the floor of the anechoic chamber 300, thus improving the accuracy of the above-mentioned EMC test.

[0047] Next, the radio wave shielding structure 1 will be described in detail.

[0048] Figure 3 This is a schematic side view of the radio wave shielding structure 1. Additionally, Figure 4 This is a schematic top view representing the radio wave shielding structure 1. Figure 4In order to visually confirm the structure beneath the floor, the metal floor 103 is described as transparent. Furthermore, Figure 3 and Figure 4 This describes an electromagnetic wave shielding structure 1 in which a flat strip 3 extends from beneath the floor, located within an opening 104 of a metal floor 103. The flat strip 3 is a component made of a conductive elastic material. For example, the flat strip 3 may be made by mixing metal powder into an elastic material such as rubber or polyurethane. Alternatively, the flat strip 3 may have a structure in which a conductive material layer covers the surface of a strip formed from an elastic material such as rubber.

[0049] The electromagnetic shielding roller 4 is a conductive roller that is positioned between the metal floor 103 and the flat belt 3 at an opening 104. It is conductive to the metal floor 103 and rotates in contact with the flat belt 3, moving in tandem with the movement of the flat belt 3. For example, the electromagnetic shielding roller 4 is mounted to the back of the metal floor 103 via a support member 5. The support member 5 is a metal component. One end of the support member 5 is mounted to the back of the metal floor 103, and a conductive rotating shaft is provided at the other end. The electromagnetic shielding roller 4 rotates around this rotating shaft and is electrically connected to the metal floor 103 via the rotating shaft and the support member 5.

[0050] In addition, such as Figure 3 As shown, the height h of the support member 5 is designed to be the position where a portion of the circumferential surface of the electromagnetic shielding roller 4 contacts the flat belt 3.

[0051] And, as Figure 4 As shown, the electromagnetic wave shielding roller 4 can also be a single roller extending along the width direction of the flat belt 3. The single-roller electromagnetic wave shielding roller 4 blocks the gap between the flat belt 3 and the metal floor 103 in the width direction, thus shielding unwanted electromagnetic waves propagating through the gap.

[0052] Furthermore, the case shown is that the radio wave shielding roller 4 is set in the portion 104A where the flat strip 3 emerges from under the floor, but it can also be set in the portion 104B where the flat strip 3 is recessed under the floor.

[0053] By installing the radio wave shielding structure 1 in these parts, unwanted radio waves can be reliably shielded. Furthermore, the radio wave shielding structure 1 can also be installed on all tires of the vehicle 100.

[0054] Figure 5 This is a schematic top view of a modified example (1) of the radio wave shielding structure 1. The metal floor 103 is shown as transparent to allow for visual confirmation of the structure beneath the floor for ease of explanation. Furthermore, Figure 6 This is a side view schematically representing a modified example (1) of the radio wave shielding structure 1. Figure 5 and Figure 6The modified example (1) of the electromagnetic shielding structure 1 shown has one or more metal sheet portions 6, which are arranged along the length direction of the flat strip 3, and pass through the opening 104 and are electrically connected in the width direction of the flat strip 3.

[0055] These metal plates 6 are electrically connected to the metal ground plane 103 at the ground potential, and therefore function as a ground plane. The metal plates 6, as... Figure 5 The component shown is envisioned as a plate, but it could also be a metal rod. By providing multiple metal plates 6 in the opening 104, the opening 104 can be blocked regardless of the rotation of the flat belt 3, thus blocking unwanted radio waves propagating through the opening 104.

[0056] In addition, Figure 5 and Figure 6 In the modified example (1) shown, as indicated by arrow C, the flat strip 3 is electrically connected to the wave shielding roller 4.

[0057] The spacing between the multiple metal plates 6 arranged in the opening 104 is determined to be a spacing that prevents leakage of radio waves of a specified frequency. Radio waves with frequencies higher than the length of half a wavelength at this spacing are more prone to leakage. For example, if the upper limit of the allowed frequency in the anechoic chamber 300 is 10 GHz, then half a wavelength is 1.5 cm, so the spacing between adjacent metal plates 6 is set to be shorter than 1.5 cm. In other words, by making this spacing shorter than 1.5 cm, radio waves below 10 GHz are less likely to leak. Furthermore, if the level of electromagnetic noise generated under the floor is low, to the point that leakage from this spacing would not be a problem, then the spacing can be extended.

[0058] Figure 7 This is a top view schematically representing a modified example (2) of the radio wave shielding structure 1. The metal floor 103 is shown as transparent so that the structure under the floor can be visually confirmed for ease of explanation. Figure 7 The image on the bottom is Figure 7 An enlarged view of the area enclosed by the dashed line in the upper part of the image. (See image above.) Figure 7 As shown, the wave shielding roller 4 can also be one or more side rollers 7 or 8 provided in the opening 104 between the side of the flat belt 3 and the metal floor 103.

[0059] like Figure 7 As shown in the upper part of the figure, the side roller 7 is a conductive roller that rotates around a rotation axis directly disposed on the metal floor 103. The side roller 7 electrically connects the flat strip 3 to the metal floor 103 by contacting the thickness portion of the flat strip 3.

[0060] In addition, such as Figure 7As shown in the lower part of the figure, the side roller 8 is a conductive roller rotatably mounted on the support member 9, which is mounted on the end face of the opening 104. The support member 9 is a metal component. One end of the support member 9 is mounted on the end face of the opening 104, and a conductive rotating shaft is provided at the other end. The side roller 8 rotates around this rotating shaft and is electrically connected to the metal floor 103 via the rotating shaft and the support member 9.

[0061] The side roller 8, like the side roller 7, electrically connects the flat belt 3 to the metal floor 103 by contacting the thick portion of the flat belt 3.

[0062] By setting side rollers 7 or 8, unwanted radio waves that propagate through the gap between the side of the flat belt 3 and the metal floor 103 can be blocked.

[0063] Figure 8 This is a schematic top view of a modified example (3) of the radio wave shielding structure 1. The metal floor 103 is shown as transparent to allow for visual confirmation of the structure beneath the floor for ease of explanation. Figure 8 As shown, the wave shielding roller 4A consists of multiple partial rollers arranged along the width direction of the flat belt 3 and rotating coaxially about the rotation axis 10. Since the conductive rotation axis 10 is in communication with the metal floor 103, each partial roller functions as a conductive roller that is in communication with the metal floor 103 and in contact with the flat belt 3 and rotates along with the movement of the flat belt 3.

[0064] The electromagnetic shielding roller 4A, composed of multiple partial rollers, blocks the gap between the flat strip 3 and the metal floor 103 in the width direction, thus shielding unwanted electromagnetic waves propagating through the gap. Furthermore, in the electromagnetic shielding roller 4A, the interval d between adjacent partial rollers becomes a portion that is not conductive to the metal floor 103. Therefore, the interval d is determined to be an interval at which electromagnetic waves of a specified frequency will not leak. Electromagnetic waves with frequencies higher than the length of the interval d when it is half the wavelength are more prone to leakage.

[0065] For example, if the upper limit of the allowed frequency in the anechoic chamber 300 is 10 GHz, then half the wavelength is 1.5 cm, so the interval d is set to be shorter than 1.5 cm. In other words, by making this interval d shorter than 1.5 cm, radio waves below 10 GHz are difficult to leak. Furthermore, if the level of electromagnetic noise generated under the floor is low, to the point that leakage from this interval would not be a problem, then the interval can be extended.

[0066] Figure 9A This is a side view schematically showing a modified example (4) of the radio wave shielding structure 1. Additionally, Figure 9B This is a partial side view schematically illustrating a modified example of the radio wave shielding roller 4. Figure 9A and Figure 9BIn this configuration, conductive plates 5A and 5B are conductive parts that are in communication with the metal floor 103 and in contact with the circumferential surface of the electromagnetic shielding roller 4. The electromagnetic shielding roller 4 is electrically connected to the metal floor 103 via conductive plates 5A or 5B.

[0067] like Figure 9A As shown, the conductive plate 5A is a curved conductive plate-shaped component with one end mounted on the back side of the metal floor 103. The curvature of the curved portion of the conductive plate 5A is formed to correspond to the curvature of the radio wave shielding roller 4, and the two are in surface contact.

[0068] In addition, such as Figure 9B As shown, the conductive plate 5B is a curved, conductive block component with one end mounted on the back side of the metal floor 103. The curvature of the curved portion of the conductive plate 5B is also formed to correspond to the curvature of the electromagnetic wave shielding roller 4, just like the conductive plate 5A, and the two are in surface contact.

[0069] In this way, the conductive plates 5A and 5B are not a conductive structure based on a rotating shaft, but rather a structure that makes surface contact with the circumferential surface of the electromagnetic wave shielding roller 4. Therefore, the conductive plates 5A and 5B can reduce the impedance between themselves and the electromagnetic wave shielding roller 4, enabling a more robust grounding. Furthermore, even when the electromagnetic wave shielding roller 4 rotates, the conductive plates 5A and 5B can maintain a smooth contact.

[0070] Furthermore, the case shown is that conductive plates 5A and 5B are disposed on the radio wave shielding roller 4, but conductive plates 5A and 5B can also be disposed on each part of the aforementioned radio wave shielding roller 4A, or conductive plates 5A and 5B can be in surface contact with the peripheral surfaces of multiple part rollers.

[0071] As described above, the electromagnetic shielding structure 1 of Embodiment 1 includes: a conductive flat strip 3 wound around a pair of rollers 2 arranged parallel to each other below the surface of a metal floor 103, and the tires 101 and 102 of a vehicle 100 exposed through an opening 104 formed in the surface of the metal floor 103; and a conductive electromagnetic shielding roller 4 disposed between the metal floor 103 and the flat strip 3 at the opening 104, conductive to the metal floor 103, and in contact with the flat strip 3 and rotating in tandem with the movement of the flat strip 3. Thus, the flat strip 3 becomes at the same potential as the metal floor 103, and therefore the electromagnetic shielding structure 1 can shield unwanted electromagnetic waves propagating through the opening 104 formed in the metal floor 103 of the anechoic chamber.

[0072] In the radio wave shielding structure 1 of Embodiment 1, the radio wave shielding roller 4 is disposed at the opening 104 on either or both of the portion 104A where the flat strip emerges from under the floor and the portion 104B where it disappears under the floor, and is in contact with the flat strip 3 in the width direction. Thus, the radio wave shielding structure 1 can shield radio waves propagating through the opening 104 between the flat strip 3 and the metal floor 103.

[0073] In the radio wave shielding structure 1 of Embodiment 1, the radio wave shielding roller 4 is a single roller extending in the width direction of the flat strip 3. This allows for reliable communication between the radio wave shielding roller 4 and the flat strip 3.

[0074] In the radio wave shielding structure 1 of Embodiment 1, the radio wave shielding roller 4A is a plurality of partial rollers arranged along the width direction of the flat belt 3 and rotating coaxially. As a result, the radio wave shielding roller 4A can be reliably connected to the flat belt 3.

[0075] In the radio wave shielding structure 1 of Embodiment 1, one or more metal plates 6 are provided, which are arranged along the length direction of the flat strip 3, and pass through the opening 104 and are electrically connected in the width direction of the flat strip 3. By providing multiple metal plates 6, radio waves propagating between the lateral side of the flat strip 3 and the metal floor 103 can be shielded.

[0076] In the radio wave shielding structure 1 of Embodiment 1, the radio wave shielding rollers are one or more side rollers 7 and 8 provided in the opening 104 between the side of the flat belt 3 and the metal floor 103. By providing the side rollers, radio waves propagating between the lateral side of the flat belt 3 and the metal floor 103 can be shielded.

[0077] In the radio wave shielding structure 1 of Embodiment 1, a conductive plate 5A or 5B is provided that is in communication with the metal floor 103 and in contact with the peripheral surface of the radio wave shielding roller 4 or 4A. The radio wave shielding roller 4 or 4A is electrically connected to the metal floor 103 through the conductive plate 5A or 5B.

[0078] By incorporating conductive plates 5A or 5B, the electromagnetic wave shielding roller 4 or 4A can be reliably connected to the metal floor 103.

[0079] The chassis dynamometer system 200 of Embodiment 1 has an electromagnetic shielding structure 1, which can shield unwanted electromagnetic waves that propagate through the opening 104 formed on the metal floor 103 of the anechoic chamber.

[0080] Implementation method 2.

[0081] Figure 10 This is a schematic side view of the chassis dynamometer system 200A according to Embodiment 2. Figure 10The text describes the individual track plates that make up the track 11 separately, but in reality, adjacent track plates are connected by pins and bosses. Figure 10 In this system, the chassis dynamometer system 200A is a system capable of performing simulations of the vehicle 100 on the surface of a metal floor 103. For example, the chassis dynamometer system 200A is installed in an anechoic chamber having a metal floor 103. Figure 10 As shown, the chassis dynamometer system 200A has an electromagnetic shielding structure 1A disposed under the metal floor 103.

[0082] The radio wave shielding structure 1A includes a track 11 wound around a pair of rollers 2A and a radio wave shielding roller 4B. The pair of rollers 2A are respectively provided for the front wheel tire 101 and the rear wheel tire 102 of the vehicle 100, which is the test vehicle. An opening is formed in the metal floor 103, through which the track 11 wound on the rollers 2A protrudes into the radio wave anechoic chamber.

[0083] In addition, roller 2A is a roller with at least a conductive surface.

[0084] In addition, such as Figure 10 As shown, a pair of rollers 2A are arranged parallel to each other below the metal floor 103. Therefore, the flat portion of the track 11 wound on the rollers 2A is substantially parallel to the surface of the metal floor 103. The vehicle 100 is arranged in the anechoic chamber with tires 101 and 102 mounted on the flat portion of the track 11.

[0085] For example, by causing tire 101 to... Figure 10 As indicated by the arrow, the roller 2A rotates in the opposite direction to the tire 101, and the track 11 wound on the roller 2A also rotates. In this way, the chassis dynamometer system 200A can simulate a state close to the actual driving state of the vehicle 100 with the tires 101 and 102 of the vehicle 100 mounted on the track 11.

[0086] In addition, although Figure 10 The illustration is omitted, but a drive control device for rotating the track 11 and even the roller 2A is located below the metal floor 103. Additionally, the vehicle 100 is equipped with a test device for EMC testing. The drive control device and the test device contain electronic circuitry, which could become noise sources generating unwanted electromagnetic waves.

[0087] On the other hand, as described above, an opening is formed in the metal floor 103 of the anechoic chamber to expose the track 11. A gap is required between the track 11 and the opening in the metal floor 103 to avoid obstructing the rotational drive of the track 11. Therefore, electromagnetic noise generated by the aforementioned noise source may propagate into or out of the anechoic chamber through this gap.

[0088] To solve this problem, in the electromagnetic shielding structure 1A, a conductive electromagnetic shielding roller 4B is provided at the opening of the metal floor 103, between the peripheral surface of the roller 2A and the metal floor 103. For example, as... Figure 10 As shown, at the opening of the metal floor 103, the radio wave shielding roller 4B is disposed on either or both of the portion 104A where the track 11 emerges from under the floor and the portion 104B where it is submerged under the floor.

[0089] The electromagnetic shielding roller 4B is electrically connected to the metal floor 103, and its circumferential surface is in contact with the conductive circumferential surface of roller 2A, configured to rotate in tandem with the movement of the track 11. For example, in Figure 10 In the middle, roller 2B rotates clockwise, thereby causing the track 11 to rotate clockwise as well. The electromagnetic shielding roller 4B, which is in contact with the circumferential surface of roller 2A, rotates counterclockwise along with the rotation of the track 11.

[0090] The track 11 is constructed by connecting multiple track plates together using pins and bosses, and each track plate is conductive. Furthermore, as described above, roller 2A is a conductive roller, and the electromagnetic shielding roller 4B is a conductive component that is in contact with the metal floor 103. Therefore, through contact between the peripheral surfaces of the electromagnetic shielding roller 4B and roller 2A, the track 11 is electrically connected to the metal floor 103 via the electromagnetic shielding roller 4B, achieving the same potential (ground potential) as the metal floor 103. In this way, the track 11 functions as a large ground plane positioned at the opening formed in the metal floor 103, thus shielding electromagnetic waves propagating through the opening.

[0091] Furthermore, even when the track 11 rotates, the electromagnetic shielding roller 4B also rotates, thereby maintaining contact with the circumferential surface of the roller 2A. Therefore, the electromagnetic shielding structure 1A can electrically connect the track 11 to the metal floor 103 regardless of the rotation of the track 11.

[0092] Furthermore, the wave shielding roller 4B rotates while in contact with the roller 2A, thus achieving a less wear-prone effect compared to a structure where only the metal sheet contacts the rotating roller 2A.

[0093] Next, the EMC test using an anechoic chamber equipped with a chassis dynamometer system 200A will be explained. The chassis dynamometer system 200A can also be used by setting up... Figure 2A as well as Figure 2B The vehicle 100 is subjected to EMC testing in the anechoic chamber 300 shown. In the EMC test, only the electromagnetic waves radiated from the vehicle 100 are accurately measured, so it is necessary to eliminate electromagnetic noise from outside the vehicle 100.

[0094] The electromagnetic shielding structure 1A can block electromagnetic noise passing through the opening formed on the floor of the anechoic chamber 300, thus improving the accuracy of the above-mentioned EMC test.

[0095] Next, the radio wave shielding structure 1A will be described in detail.

[0096] Figure 11 This is a schematic side view of the radio wave shielding structure 1A. (e.g.) Figure 11 As shown, at the opening 104 of the metal floor 103, an electromagnetic shielding structure 1A is shown, located at the portion 104A of the track 11 emerging from under the floor. The electromagnetic shielding roller 4B is a conductive roller, which is disposed at the opening 104 between the metal floor 103 and the roller 2A, is conductive to the metal floor 103, and rotates in contact with the roller 2A in sync with the movement of the track 11.

[0097] For example, the radio wave shielding roller 4B is mounted on the back of the metal floor 103 via a support member 5. The support member 5 is a metal component. One end of the support member 5 is mounted on the back of the metal floor 103, and a conductive rotating shaft is provided at the other end. The radio wave shielding roller 4B rotates around this rotating shaft and is electrically connected to the metal floor 103 via the rotating shaft and the support member 5.

[0098] In addition, the height h of the support member 5 is designed to be the position where a part of the circumferential surface of the radio wave shielding roller 4B contacts the circumferential surface of the roller 2A.

[0099] Figure 12 This is a schematic top view of the radio wave shielding structure 1A. The metal floor 103 is shown as transparent so that the structure under the floor can be visually confirmed for ease of explanation.

[0100] Figure 13A This is a schematic front view of the roller 2A representing the radio wave shielding structure 1A, showing the state in which the track 11 is wound around the roller 2A. Figure 13B This is a schematic front view of the roller 2A of the radio wave shielding structure 1A, showing the state in which the track 11 has been removed from the roller 2A.

[0101] Figure 14A This is a schematic front view of the radio wave shielding structure 1A, showing the state in which the track 11 is wound on the roller 2A. Figure 14B This is a schematic front view of the radio wave shielding structure 1A, showing the state where the track 11 has been removed from the roller 2A.

[0102] exist Figure 11 , Figure 12 , Figure 13A as well as Figure 14AIn the text, each track plate constituting the track 11 is described separately, but in reality, adjacent track plates are connected by pins and bosses.

[0103] like Figure 12 As shown in Figures 13 and 14, roller 2A functions as the drive wheel for driving track 11. For example, although in Figure 13B and Figure 14B The diagram is omitted, but gears for driving the track 11 may also be formed in the portion of the wound track 11 adjacent to the peripheral surface 3A of roller 2A. Figure 12 In Figures 13 and 14, three tracks 11 are wound around a pair of rollers 2A, but it can also be a single track.

[0104] In addition, the wave shielding roller 4B is a conductive multi-part roller, which is disposed between the metal floor 103 and the peripheral surface 3A at the opening 104, is in communication with the metal floor 103, and contacts the peripheral surface 3A of the roller 2A and rotates in sync with the movement of the track 11.

[0105] The electromagnetic shielding roller 4B, composed of multiple partial rollers, blocks the gap between the conveyor belt 11 and the metal floor 103 in the width direction, thus shielding unwanted electromagnetic waves propagating through the gap. Furthermore, in the electromagnetic shielding roller 4B, the interval between adjacent partial rollers becomes a portion that is not conductive to the metal floor 103. Therefore, this interval is determined to be an interval at which electromagnetic waves of a specified frequency will not leak. Electromagnetic waves with frequencies higher than the interval d is half the wavelength in length are more prone to leakage. For example, if the upper limit frequency allowed in the anechoic chamber 300 is 10 GHz, then half the wavelength is 1.5 cm, therefore the interval between the partial rollers is set to be shorter than 1.5 cm.

[0106] In other words, by making the gap shorter than 1.5cm, electromagnetic waves below 10GHz are less likely to leak. Furthermore, if the level of electromagnetic noise generated under the floor is low enough that leakage from this gap would not be a problem, the gap can be extended.

[0107] The flat belt 3 shown in Embodiment 1 is made of rubber or polyurethane, etc. Therefore, when the flat belt 3 is lengthened to accommodate the wheelbase of the vehicle 100, deflection due to elasticity is likely to occur. In this case, if the width of the flat belt 3 is increased, deflection can be reduced, but correspondingly, the digging area for configuring the chassis dynamometer system 200 becomes wider.

[0108] In contrast, the track 11 can vary its total length in units of a spacing determined by a single track plate by adjusting the number of track plates used. Therefore, it has the advantage of being easy to construct the track 11 with a length that matches the dimensions of the anechoic chamber 300.

[0109] Furthermore, the example shown is of a case where the radio wave shielding roller 4B is provided in the portion 104A where the track 11 emerges from under the floor, but it can also be provided in the portion 104B where the track 11 is submerged under the floor.

[0110] By installing the radio wave shielding structure 1A in these parts, unwanted radio waves can be reliably shielded. Furthermore, the radio wave shielding structure 1A can also be installed on all tires of the vehicle 100.

[0111] Alternatively, the electromagnetic shielding roller 4B can also be a single roller extending in the width direction of the flat belt 3. For example, by providing a recess on the circumferential surface of the roller in a manner that avoids the track 11, the electromagnetic shielding roller 4B can be constructed from a single roller. The single-roller electromagnetic shielding roller 4B blocks the gap between the track 11 and the metal floor 103 in the width direction of the track 11, thus shielding unwanted electromagnetic waves propagating through the gap.

[0112] Alternatively, the radio wave shielding structure 1A can also be configured with... Figure 5 as well as Figure 6 The metal sheet shown is part 6.

[0113] The metal plate portion 6 in the radio wave shielding structure 1A consists of one or more metal plates arranged along the length direction of the track 11 and traversing the opening 104 in the width direction of the track 11 and electrically connected. These metal plate portions 6 are electrically connected to the metal ground plane 103, which serves as a grounding potential, and thus function as a grounding surface. The metal plate portion 6 is envisioned as a plate-shaped component, but it can also be a metal rod. By providing multiple metal plate portions 6 in the opening 104, the opening 104 can be blocked regardless of the rotation of the track 11, thus blocking unwanted radio waves propagating through the opening 104.

[0114] In the radio wave shielding structure 1A, the spacing between the plurality of metal plates 6 arranged in the opening 104 is determined to be a spacing that prevents radio waves of a specified frequency from leaking. Radio waves with frequencies higher than the length of half a wavelength at this spacing are more likely to leak. For example, if the upper limit frequency allowed in the anechoic chamber 300 is 10 GHz, then half a wavelength is 1.5 cm, therefore the spacing between adjacent metal plates 6 is set to be shorter than 1.5 cm. In other words, by making this spacing shorter than 1.5 cm, radio waves below 10 GHz are difficult to leak. Furthermore, if the level of electromagnetic noise generated under the floor is low, to the point that leakage from this spacing would not be a problem, then the spacing can be extended.

[0115] Alternatively, the radio wave shielding structure 1A can also be configured with... Figure 7 The side roller shown.

[0116] That is, the wave shielding roller 4B can also be one or more side rollers 7 or 8 provided in the opening 104 between the side of the track 11 and the metal floor 103.

[0117] like Figure 7 As shown in the upper part of the figure, the side roller 7 is a conductive roller that rotates around a rotation axis directly disposed on the metal floor 103. The side roller 7 electrically connects the track 11 to the metal floor 103 by contacting the thickness portion of the track 11.

[0118] In addition, such as Figure 7 As shown in the lower part of the figure, the side roller 8 is a conductive roller rotatably mounted on the support member 9, which is mounted on the end face of the opening 104. The support member 9 is a metal component. One end of the support member 9 is mounted on the end face of the opening 104, and a conductive rotating shaft is provided at the other end. The side roller 8 rotates around this rotating shaft and is electrically connected to the metal floor 103 via the rotating shaft and the support member 9.

[0119] The side roller 8, like the side roller 7, electrically connects the track 11 to the metal floor 103 by contacting the thick portion of the track 11.

[0120] By setting side rollers 7 or 8, unwanted radio waves that propagate through the gap between the side of the track 11 and the metal floor 103 can be blocked.

[0121] Alternatively, the radio wave shielding structure 1A can also be configured with... Figure 9A and Figure 9B The conductive plates 5A and 5B are shown. Conductive plates 5A and 5B are conductive plates that are in communication with the metal floor 103 and in contact with the circumferential surface of the electromagnetic shielding roller 4B. The electromagnetic shielding roller 4B is electrically connected to the metal floor 103 through conductive plates 5A or 5B.

[0122] like Figure 9A As shown, the conductive plate 5A is a curved conductive plate-shaped component with one end mounted on the back side of the metal floor 103. The curvature of the curved portion of the conductive plate 5A is formed to correspond to the curvature of the radio wave shielding roller 4B, and the two are in surface contact.

[0123] In addition, such as Figure 9B As shown, the conductive plate 5B is a curved, conductive block component with one end mounted on the back side of the metal floor 103. The curvature of the curved portion of the conductive plate 5B is also formed to correspond to the curvature of the electromagnetic wave shielding roller 4B, just like the conductive plate 5A, and the two are in surface contact.

[0124] In this way, the conductive plates 5A and 5B are not a conductive structure based on a rotating shaft, but rather a structure that makes surface contact with the circumferential surface of the electromagnetic wave shielding roller 4B. Therefore, the conductive plates 5A and 5B can reduce the impedance between themselves and the electromagnetic wave shielding roller 4B, enabling a more robust grounding. Furthermore, even if the electromagnetic wave shielding roller 4B rotates, the conductive plates 5A and 5B can maintain a smooth contact.

[0125] As described above, the electromagnetic shielding structure 1A of Embodiment 2 includes: a track 11 wound around a pair of rollers 2A arranged parallel to each other under the surface of a metal floor 103, and a tire 101 and 102 of a vehicle 100 exposed from an opening 104 formed in the metal floor 103; a conductive peripheral surface 3A disposed on the peripheral surface of one or both of the rollers 2A; and a conductive electromagnetic shielding roller 4B disposed between the metal floor 103 and the peripheral surface 3A at the opening 104, communicating with the metal floor 103, and rotating in contact with the peripheral surface 3A in conjunction with the movement of the track 11. Thus, the electromagnetic shielding structure 1A can shield electromagnetic waves propagating through the opening 104 between the peripheral surface 3A of the rollers 2A provided in the chassis dynamometer system 200 and the metal floor 103.

[0126] In the radio wave shielding structure 1A of Embodiment 2, the radio wave shielding roller 4B is disposed in the opening 104 on either or both of the portion 104A where the track 11 emerges from under the floor and the portion 104B where it is submerged under the floor. Thus, the radio wave shielding structure 1A can shield radio waves propagating through the opening 104 between the peripheral portion 3A and the metal floor 103.

[0127] In the radio wave shielding structure 1A of Embodiment 2, the radio wave shielding roller 4B is a single roller extending in the width direction of the roller 2A around which the track 11 is wound. As a result, the radio wave shielding roller 4B can be reliably connected to the peripheral surface 3A.

[0128] In the radio wave shielding structure 1A of Embodiment 2, the radio wave shielding roller 4B is a plurality of partial rollers arranged and coaxially rotating along the width direction of the roller 2A on which the track 11 is wound. As a result, the radio wave shielding roller 4B can be reliably connected to the peripheral surface 3A.

[0129] In the radio wave shielding structure 1A of Embodiment 2, one or more metal plates 6 are provided, which are arranged along the length direction of the track 11, and pass through the opening 104 and are electrically connected in the width direction of the track 11. By providing multiple metal plates 6, radio waves propagating through the opening 104 can be shielded.

[0130] In the radio wave shielding structure 1A of Embodiment 2, a conductive plate 5A or 5B is provided that is electrically connected to the metal floor 103 and in contact with the peripheral surface of the radio wave shielding roller 4B. The radio wave shielding roller 4B is electrically connected to the metal floor 103 via the conductive plate 5A or 5B. By making the conductive plate 5A or 5B in contact with the peripheral surface 3A of the radio wave shielding roller 4B, the contact area between the two is increased. As a result, the radio wave shielding structure 1A can reliably connect the radio wave shielding roller 4B to the metal floor 103.

[0131] In the radio wave shielding structure 1A of Embodiment 2, the track 11 is conductive. By making the conductive track 11 connected to the metal floor 103, the floor surface area including the opening 104 becomes a large ground, thus enabling the shielding of unwanted radio waves propagating through the opening 104 into and out of the anechoic chamber.

[0132] In the radio wave shielding structure 1A of Embodiment 2, the radio wave shielding roller 4B is one or more side rollers provided in the opening 104 between the side of the track 11 and the metal floor 103. This allows for reliable communication between the radio wave shielding roller 4B and the track 11.

[0133] The chassis dynamometer system 200A of Embodiment 2 has an electromagnetic shielding structure 1A, which can shield unwanted electromagnetic waves that propagate through the opening 104 formed on the metal floor 103 of the anechoic chamber.

[0134] Furthermore, it is possible to combine the various embodiments, modify any constituent element of each embodiment, or omit any constituent element of each embodiment.

[0135] Industrial availability

[0136] The radio wave shielding structure disclosed herein can be used, for example, in a chassis dynamometer system configured in an anechoic chamber.

[0137] Label Explanation

[0138] 1. 1A: Radio wave shielding structure; 2. 2A, 2B: Rollers; 3: Flat belt; 3A: Peripheral section; 4. 4A, 4B: Radio wave shielding rollers; 5. 9: Support components; 5A, 5B: Conductive plates; 6: Metal sheet section; 7. 8: Side rollers; 10: Rotating shaft; 11: Track; 100: Vehicle; 101, 102: Tires; 103: Metal floor; 104: Opening; 104A, 104B: Parts; 200, 200A: Chassis dynamometer system; 300: Anechoic chamber; 301: Antenna mast; 302: Receiving antenna.

Claims

1. A radio wave shielding structure, which is a radio wave shielding structure of a chassis dynamometer system capable of performing vehicle simulation on a metal floor, characterized in that, The radio wave shielding structure includes: A conductive flat strip, wound around a pair of rollers arranged parallel to each other under the metal floor surface, protrudes from an opening formed in the metal floor surface to carry the tires of the vehicle; as well as A conductive electromagnetic shielding roller is disposed at the opening between the metal floor and the flat belt, is in communication with the metal floor, and is in contact with the flat belt and rotates in tandem with the movement of the flat belt.

2. The radio wave shielding structure according to claim 1, characterized in that, The electromagnetic shielding roller is positioned at the opening on either or both of the portion of the flat strip that emerges from under the floor and the portion that extends into under the floor, and is in contact with the width direction of the flat strip.

3. The radio wave shielding structure according to claim 2, characterized in that, The radio wave shielding roller is a single roller extending along the width direction of the flat strip.

4. The radio wave shielding structure according to claim 2, characterized in that, The radio wave shielding roller is a plurality of partial rollers arranged along the width direction of the flat strip and rotating coaxially.

5. The radio wave shielding structure according to any one of claims 1 to 4, characterized in that, The electromagnetic shielding structure includes one or more metal plates that are disposed along the length of the flat strip, pass through the opening in the width direction of the flat strip, and are electrically connected.

6. The radio wave shielding structure according to any one of claims 1 to 4, characterized in that, The radio wave shielding roller is one or more side rollers disposed at the opening between the side of the flat strip and the metal floor.

7. The radio wave shielding structure according to any one of claims 1 to 6, characterized in that, The electromagnetic shielding structure includes a conductive portion that is in communication with the metal floor and contacts the circumferential surface of the electromagnetic shielding roller. The electromagnetic shielding roller is electrically connected to the metal floor via the conductive part.

8. A radio wave shielding structure, which is a radio wave shielding structure of a chassis dynamometer system capable of performing vehicle simulation on a metal floor, characterized in that, The radio wave shielding structure includes: Tracks, which are wound around a pair of rollers arranged parallel to each other under the metal floor surface, protrude from an opening formed in the metal floor surface to carry the tires of the vehicle; A conductive peripheral surface is disposed on the peripheral surface of one or both of the pair of rollers; as well as A conductive electromagnetic shielding roller is disposed between the metal floor and the roller at the opening, is in communication with the metal floor, and contacts the peripheral surface and rotates in tandem with the movement of the track.

9. The radio wave shielding structure according to claim 8, characterized in that, The radio wave shielding roller is disposed at the opening on either or both of the portion of the track that emerges from under the floor and the portion that retracts into the floor.

10. The radio wave shielding structure according to claim 9, characterized in that, The radio wave shielding roller is a single roller extending along the width direction of the roller on which the track is wound.

11. The radio wave shielding structure according to claim 9, characterized in that, The radio wave shielding roller is a plurality of partial rollers arranged along the width direction of the roller on which the track is wound and rotating coaxially.

12. The radio wave shielding structure according to any one of claims 8 to 11, characterized in that, The electromagnetic shielding structure includes one or more metal plates that are disposed along the length of the track, pass through the opening in the width direction of the track, and are electrically connected.

13. The radio wave shielding structure according to any one of claims 8 to 12, characterized in that, The electromagnetic shielding structure includes a conductive portion that is in communication with the metal floor surface and in contact with the circumferential surface of the electromagnetic shielding roller. The electromagnetic shielding roller is electrically connected to the metal floor via the conductive part.

14. The radio wave shielding structure according to any one of claims 8 to 13, characterized in that, The track is conductive.

15. The radio wave shielding structure according to claim 14, characterized in that, The radio wave shielding roller is one or more side rollers disposed at the opening between the side of the track and the metal floor.

16. A chassis dynamometer system, characterized in that, The chassis dynamometer system has the radio wave shielding structure described in any one of claims 1 to 15.

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