Electromagnetic wave blocking structure and chassis dynamometer system

Abstract

Electromagnetic wave-blocking structure (1) comprises: an electrically conductive flat belt (3) wound around a pair of rollers (2) arranged parallel under a metal base (103) and exposed through an opening (104) formed in the metal base (103) so that a tire (101 and 102) of a vehicle (100) is arranged on it; and an electrically conductive electromagnetic wave-blocking roller (4) arranged between the metal base (103) and the flat belt (3) at the opening (104), conductively connected to the metal base (103) and in contact with the flat belt (3) to rotate together with the movement of the flat belt (3).

Description

TECHNICAL AREA

[0001] The present disclosure relates to an electromagnetic wave blocking structure and a chassis dynamometer system. BACKGROUND ON THE STATE OF THE TECHNOLOGY

[0002] Chassis dynamometer systems are systems for conducting tests related to the driving behavior of vehicles, measuring, for example, the forces exerted by rotating tires, the circumferential speed of the tires, and similar parameters.

[0003] In a case where vehicles of the same model with different wheelbases (i.e., the distance between the front and rear wheels) are being tested, conventional chassis dynamometer systems require the distance between the front and rear wheel rollers to be adjusted to match the wheelbase. This necessitates extensive construction work, including breaking up the floor and modifying the distance between the front and rear wheel rollers to accommodate the wheelbase.

[0004] For example, there is a vehicle test device described in patent literature 1 as a conventional technology for solving the problem. This vehicle test device is a chassis dynamometer system comprising a pair of rollers arranged parallel under the floor and a flat belt wound around the rollers. Differences in the wheelbase of the vehicles are compensated for by the longitudinal length of the flat belt. This eliminates the need for construction work to move the rollers to adapt to different wheelbases, and tests can be performed on various vehicle models. REFERENCE LIST PATENT LITERATURE

[0005] Patent Literature 1: JP-2011-162912-A SUMMARY OF THE INVENTIONAL PROBLEM

[0006] It is necessary to arrange a chassis dynamometer system in an electromagnetically reflection-free chamber when electromagnetic compatibility (EMC) tests are performed by simulating vehicle driving. Furthermore, a metal floor is used for the electromagnetically reflection-free chamber to shield against electromagnetic interference. In a case where a chassis dynamometer system with a flat belt is arranged in such an electromagnetically reflection-free chamber, it is necessary to create an opening in one area of ​​the metal floor and to provide access to the flat belt through this opening.For this reason, conventional chassis dynamometer systems had the problem that electromagnetic disturbances emanating from the drive unit of a flat belt and electromagnetic disturbances emanating from a device under test in an electromagnetically reflection-free space could be transmitted through the opening into the interior and exterior of the electromagnetically reflection-free space.

[0007] The present disclosure aims to solve this problem, and its objective is to obtain an electromagnetic wave blocking structure that can block electromagnetic waves propagating through an opening formed in a surface of a metal floor in a room in which a chassis dynamometer system is arranged. SOLUTION TO THE TASK

[0008] An electromagnetic wave blocking structure according to the present disclosure is an electromagnetic wave blocking structure included in a chassis dynamometer system capable of simulating a vehicle over a metal floor, comprising: an electrically conductive flat belt wound around a pair of rollers arranged parallel under the metal floor and exposed through an opening in the surface of the metal floor such that a tire of the vehicle is arranged thereon; and an electrically conductive electromagnetic wave blocking roller arranged between the metal floor and the flat belt at the opening, conductively connected to the surface of the metal floor and in contact with the flat belt to rotate with the movement of the flat belt. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0009] According to the present disclosure, the structure comprises an electrically conductive flat belt, exposed through an opening in a surface of a metal base, upon which a vehicle tire is mounted, and an electrically conductive electromagnetic wave-blocking roller, arranged between the metal base and the flat belt at the opening, conductively connected to the metal base and in contact with the flat belt to rotate with the movement of the flat belt. This places the flat belt and the metal base at the same potential. Accordingly, the electromagnetic wave-blocking structure according to the present disclosure can block electromagnetic waves propagating through the opening formed in the surface of the metal base in a space in which a chassis dynamometer system is arranged. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a side view schematically showing a chassis dynamometer system according to a first embodiment. The Fig. 2A and Fig. 2B are drawings that schematically illustrate an EMC test on a vehicle, which is carried out in an electromagnetically reflection-free room. Fig. Figure 3 is a side view that schematically shows a wave-blocking structure according to a first embodiment. Fig. Figure 4 is a top view that schematically illustrates the electromagnetic wave blocking structure according to the first embodiment. Fig. Figure 5 is a top view illustrating schematically a modification example (1) of the electromagnetic wave blocking structure according to the first embodiment. Fig. Figure 6 is a side view that schematically illustrates a modification example (1) of the electromagnetic wave blocking structure according to the first embodiment. Fig. Figure 7 is a top view illustrating schematically a modification example (2) of the electromagnetic wave blocking structure according to the first embodiment. Fig. Figure 8 is a top view illustrating schematically a modification example (3) of the electromagnetic wave blocking structure according to the first embodiment. The Fig. 9A and Fig. Figure 9B shows side views that schematically illustrate a modification example (4) of the electromagnetic wave blocking structure according to the first embodiment. Fig. Figure 10 is a side view schematically showing a chassis dynamometer system according to a second embodiment. Fig. Figure 11 is a side view schematically showing an electromagnetic wave blocking structure according to the second embodiment. Fig. Figure 12 is a top view schematically showing an electromagnetic wave blocking structure according to the second embodiment. The Fig. 13A and Fig. Figure 13B shows front views schematically illustrating a role of the electromagnetic wave blocking structure according to the second embodiment. The Fig. 14A and Fig. Figure 14B are front views showing schematic representations of the front views of the electromagnetic wave blocking structure according to the second embodiment. DESCRIPTION OF THE EXECUTION FORMS First embodiment.

[0010] Fig. Figure 1 is a side view schematically showing a chassis dynamometer system 200 according to a first embodiment. Fig. 1. The chassis dynamometer system 200 is a system that can perform simulations of a vehicle 100 on the surface of a metal floor 103. For example, the chassis dynamometer system 200 is provided in an electromagnetically reflection-free room with a metal floor 103. As in Fig. As shown in Figure 1, the chassis dynamometer system 200 comprises an electromagnetic wave blocking structure 1 which is arranged under the metal floor 103.

[0011] The electromagnetic wave blocking structure 1 comprises: a flat belt 3, which is intended for the front tires 101 and rear tires 102 of the vehicle 100 to be tested and is wound around a pair of rollers 2; and an electromagnetic wave blocking roller 4. An opening is formed in the metal base 103, and the flat belt 3 wound around the rollers 2 is exposed through the opening to the interior of the electromagnetically reflection-free space.

[0012] As in Fig. As shown in Figure 1, the pair of rollers 2 are arranged parallel to each other under the metal base 103. For this reason, the flat part of the flat belt 3 wound around the rollers 2 runs almost parallel to the surface of the metal base 103. The vehicle 100 is positioned in the electromagnetically reflection-free space in such a way that the tires 101 and 102 are placed on the flat part of the flat belt 3.

[0013] For example, if the tires 101 point in the direction of the Fig. When the rollers 2 are rotated in the direction indicated by arrow 1, they rotate in the opposite direction to the tires 101, and the flat belt 3 wound around the rollers 2 also rotates accordingly. In this way, the chassis dynamometer system 200 is able to simulate conditions that closely approximate the actual operation of the vehicle 100 when the tires 101 and 102 of the vehicle 100 are placed on the flat belt 3.

[0014] It should be noted that, although in Fig. 1. Not shown in Figure 1, a motor drive control device for rotating the flat belt 3, i.e., for rotating the rollers 2, is located under the metal base 103; furthermore, a device to be tested, which is subjected to an EMC test, is mounted on the vehicle 100. Electronic circuits are attached to the drive control device and the device to be tested and can generate unnecessary electromagnetic waves as sources of interference.

[0015] On the other hand, as mentioned above, the opening for exposing the flat belt 3 is formed in the metal base 103 of the electromagnetically reflection-free space. It is necessary to provide gaps between the flat belt 3 and the opening in the metal base 103 to prevent the metal base 103 from obstructing the rotation of the flat belt 3. For this reason, there is a possibility that electromagnetic interference generated in the interference sources could be transmitted through the gaps into the interior and exterior of the electromagnetically reflection-free space.

[0016] To solve this problem, the electromagnetic wave blocking structure 1 is provided with the electrically conductive electromagnetic wave blocking roller 4 between the metal base 103 and the electrically conductive flat belt 3 at the opening of the metal base 103.

[0017] For example, in Fig. As shown in Figure 1, the electromagnetic wave blocking roller 4 is arranged at the opening of the metal base 103 either on a part 104A where the flat belt 3 emerges from under the base, or on a part 104B where the flat belt 3 runs under the base, or on both parts.

[0018] The electromagnetic wave-blocking roller 4 is conductively connected to the metal base 103 and arranged such that its circumferential surface is in contact with the flat belt 3. The electromagnetic wave-blocking roller 4 is configured to rotate together with the movement of the flat belt 3.

[0019] For example, in Fig. 1. Due to the clockwise rotation of the rollers 2, the flat belt 3 also rotates clockwise. The electromagnetic wave-blocking roller 4, which is in contact with the flat belt 3, rotates counterclockwise along with the rotation of the flat belt 3.

[0020] The flat belt 3 is electrically conductive, at least on its surface, and the electromagnetic wave-blocking roller 4 is an electrically conductive element that is conductively connected to the metal base 103. Therefore, the flat belt 3 is electrically connected to the metal base 103 via the electromagnetic wave-blocking roller 4 and reaches the same potential (ground potential) as the metal base 103.

[0021] In this way, the flat belt 3 acts as a large base surface arranged at the opening formed in the metal base 103. Accordingly, it is possible to block electromagnetic waves propagating through the opening.

[0022] Furthermore, the electromagnetic wave-locking roller 4 remains in contact with the flat belt 3 by rotating along with the rotation of the flat belt 3, even when the flat belt 3 is rotating. For this reason, the electromagnetic wave-locking structure 1 can electrically connect the flat belt 3 to the metal base 103 regardless of the flat belt 3's rotation. Since the electromagnetic wave-locking roller 4 rotates while remaining in contact with the flat belt 3, it also has the advantage of being less susceptible to wear and other abrasion compared to a design where metal parts are simply brought into contact with the rotating flat belt 3.

[0023] Next, a summary of an EMC test using an electromagnetically reflection-free room including the chassis dynamometer system 200 will be explained. Fig. Figure 2A is a top view schematically illustrating the EMC test on vehicle 100, which is performed in an electromagnetically reflection-free room 300. Furthermore, Fig. Figure 2B shows a front view schematically illustrating the EMC test on vehicle 100, which is carried out in the electromagnetically reflection-free room 300. Fig. 2A and Fig. Figure 2B shows the electromagnetically reflection-free room 300, in which the EMC measurement of the vehicle 100 is carried out. It should be noted that, although in the Fig. 2A and Fig. 2B, where no illustration is shown, it is assumed that the information in Fig. 1 The chassis dynamometer system 200 shown is arranged in the electromagnetically reflection-free space 300.

[0024] For EMC measurement, a receiving antenna 302 is used, which is attached to an antenna mast 301. As, for example, in Fig. As shown in Figure 2A, the receiving antenna 302 is mounted on the antenna mast 301 at a height of 3 m above the ground. The distance D between the receiving antenna 302 and the vehicle 100 is a measurement distance in the EMC measurement and is set to a distance of, for example, 3 m or 10 m.

[0025] In the EMC test, for example, the electromagnetic waves emitted by vehicle 100 are measured with the receiving antenna 302, simulating the driving state of vehicle 100 by moving it on the flat belt 3. The test can then be performed by changing the measuring distance D. Since the EMC test aims to accurately measure only the electromagnetic waves emitted by vehicle 100, electromagnetic interference from sources other than vehicle 100 must be excluded.

[0026] Since the electromagnetic wave blocking structure 1 can shield electromagnetic interference through the opening in the bottom of the electromagnetically reflection-free space 300, it is possible to improve the accuracy of the above-mentioned EMC test.

[0027] Next, the electromagnetic wave blocking structure 1 will be explained in detail.

[0028] Fig. Figure 3 is a side view that schematically illustrates the electromagnetic wave blocking structure 1. Furthermore, Fig. Figure 4 shows a top view schematically illustrating the electromagnetic wave blocking structure 1. Fig. Figure 4 shows the metal floor 103 as transparent to reveal the structure beneath the floor. Furthermore, the Fig. 3 and Fig. 4 The electromagnetic wave blocking structure 1 is provided on part 104A, where the flat belt 3 emerges from under the base at an opening 104 in the metal base 103. The flat belt 3 is an element containing an electrically conductive elastic material. For example, the flat belt 3 can be manufactured by incorporating metal powder into an elastic material such as rubber or urethane. Furthermore, the flat belt 3 can be manufactured by coating the surface of a belt formed from an elastic material such as rubber with a layer of an electrically conductive material.

[0029] The electromagnetic wave-blocking roller 4 is an electrically conductive roller located between the metal base 103 and the flat belt 3 at the opening 104. It is conductively connected to the metal base 103 and in contact with the flat belt 3, rotating in conjunction with the belt's movement. For example, the electromagnetic wave-blocking roller 4 is attached to the rear of the metal base 103 by a support element 5. The support element 5 is a metallic element. One end of the support element 5 is attached to the rear of the metal base 103, and the other end of the support element 5 is provided with an electrically conductive rotating shaft. The electromagnetic wave-blocking roller 4 rotates around the rotating shaft and is electrically connected to the metal base 103 via the rotating shaft and the support element 5.

[0030] Furthermore, as in Fig. 3 shown, the height h of the support element 5 is designed such that a part of the circumferential surface of the electromagnetic wave blocking roller 4 is arranged so that this part comes into contact with the flat belt 3.

[0031] Furthermore, the electromagnetic wave blocking roller 4, as described in Fig. Figure 4 shows a single roller or cylinder extending in the width direction of the flat belt 3. The single electromagnetic wave blocking roller 4 blocks the gap between the flat belt 3 and the metal base 103 in the width direction of the flat belt 3. Accordingly, it is possible to block unwanted electromagnetic waves propagating through the gap.

[0032] It should be noted that in the case shown, the electromagnetic wave blocking roller 4 is provided on part 104A where the flat belt 3 emerges from under the floor, but the electromagnetic wave blocking roller 4 can also be provided on part 104B where the flat belt 3 runs under the floor.

[0033] By providing the electromagnetic wave blocking structure 1 in these areas, it is possible to reliably block unwanted electromagnetic waves. Furthermore, the electromagnetic wave blocking structure 1 can be provided for all tires of the vehicle 100.

[0034] Fig. Figure 5 is a top view schematically illustrating a modification example (1) of the electromagnetic wave blocking structure 1, and shows the metal base 103 as transparent for the sake of clarity, to make the structure beneath the base visible. Furthermore, Fig. Figure 6 shows a side view schematically illustrating modification example (1) of electromagnetic wave blocking structure 1. The [unclear text] in the Fig. 5 and Fig. 6 Modification example (1) of the electromagnetic wave blocking structure 1 is provided with one or more metal part areas 6 which are arranged along the longitudinal direction of the flat belt 3, cross the opening 104 in the width direction of the flat belt 3 and are electrically connected.

[0035] Since the metal part area 6 is electrically connected to the metal base 103 at earth potential, the metal parts 6 function as ground surfaces. While it is assumed that the metal part areas 6, as in Fig. Figure 5 shows plate-shaped elements, which can also be metal rods. By providing a variety of metal part areas 6 at the opening 104, it is possible to block the opening 104 and cut off unnecessary electromagnetic waves propagating through the opening 104, regardless of the rotation of the flat belt 3.

[0036] It should be noted that the flat belt 3 and the electromagnetic wave-blocking roller 4 are also electrically connected, as indicated by arrow C in the diagram. Fig. 5 and Fig. 6. Modification example (1) shown.

[0037] The spacing between the multiple metal part sections 6 arranged at the opening 104 is set to prevent the escape of electromagnetic waves with a predetermined frequency. Electromagnetic waves with frequencies higher than the frequency at which this spacing corresponds to half a wavelength are more likely to escape. For example, if the upper frequency limit tolerated in the electromagnetically reflection-free space 300 is 10 GHz, half a wavelength is 1.5 cm. Accordingly, the spacing between the adjacent metal part sections 6 is reduced to less than 1.5 cm. In other words, by reducing the spacing to less than 1.5 cm, the probability of electromagnetic waves with frequencies of 10 GHz or less escaping is reduced.It should be noted that the distance can be increased if the electromagnetic interference generated under the ground is low and the escape of the electromagnetic interference from the distance is not a problem.

[0038] Fig. Figure 7 is a top view schematically illustrating a modification example (2) of the electromagnetic wave-blocking structure 1, and shows the metal base 103 as transparent for the sake of simplicity, to make the structure beneath the base visible. The lower drawing in Fig. Figure 7 is an enlarged view of an area shown in the upper drawing. Fig. 7 is surrounded by a dashed line. As in Fig. As shown in Figure 7, the electromagnetic wave blocking roller 4 can be one or more side surface rollers 7 or 8, which are provided between the side surfaces of the flat belt 3 and the metal base 103 at the opening 104.

[0039] As shown in the drawing above in Fig. As shown in Figure 7, a side-surface roller 7 is an electrically conductive roller that rotates around a rotating shaft provided directly on the metal base 103. The side-surface roller 7 electrically connects the flat belt 3 and the metal base 103 by making contact with the flat belt 3 at a thickened area of ​​the flat belt 3.

[0040] Furthermore, as shown in the drawing below in Fig. Figure 7 shows a side-surface roller 8, an electrically conductive roller freely rotatable on a support element 9, which is attached to an end face of the opening 104. The support element 9 is a metallic element. One end of the support element 9 is attached to the rear of the metal base 104, and the other end of the support element 9 is provided with an electrically conductive rotating shaft. The side-surface roller 8 rotates around the rotating shaft and is electrically connected to the metal base 103 via the rotating shaft and the support element 9.

[0041] Similar to the side surface roller 7, the side surface roller 8 also electrically connects the flat belt 3 and the metal base 103 by making contact with the flat belt 3 at a thickened point on the flat belt 3.

[0042] By providing the side surface rollers 7 or 8, it is possible to cut off unnecessary electromagnetic waves that propagate through the gaps between the side surfaces of the flat belt 3 and the metal base 103.

[0043] Fig. Figure 8 is a top view schematically illustrating a modification example (3) of the electromagnetic wave blocking structure 1, and shows the metal base 103 as transparent for the sake of simplicity, to make the structure beneath the base visible. As in Fig. As shown in Figure 8, an electromagnetic wave-blocking roller 4A consists of a plurality of sub-rollers arranged in the width direction of the flat belt 3 and rotating coaxially around a rotating shaft 10. Since the electrically conductive rotating shaft 10 is conductively connected to the metal base 103, the individual sub-rollers function as electrically conductive rollers that are conductively connected to the metal base 103 and are in contact with the flat belt 3 in order to rotate together with the movement of the flat belt 3.

[0044] The electromagnetic wave blocking roller 4A, with its multiple sub-rollers, blocks the gap between the flat belt 3 and the metal base 103 in the width direction of the flat belt 3. This effectively blocks unwanted electromagnetic waves propagating through the gap. It should be noted that the distance d between adjacent sub-rollers in the electromagnetic wave blocking roller 4A is a non-conductive area connected to the metal base 103. Therefore, the distance d is set to prevent the escape of electromagnetic waves with a predetermined frequency. Electromagnetic waves with frequencies higher than the frequency at which the distance d corresponds to half a wavelength are more likely to escape.

[0045] For example, if the upper frequency limit tolerated in the electromagnetically reflection-free space 300 is 10 GHz, half the wavelength is 1.5 cm. Accordingly, the distance d is made shorter than 1.5 cm. In other words, reducing the distance d to less than 1.5 cm decreases the probability of electromagnetic waves with frequencies of 10 GHz or lower escaping. It should be noted that the distance can be increased if the electromagnetic disturbance generated under the ground is low and the escape of the electromagnetic disturbance from the distance is not a problem.

[0046] Fig. Figure 9A is a side view that schematically shows a modification example (4) of the structure to the electromagnetic wave blocking structure 1. Fig. Figure 9B is a partial side view that schematically shows a modification example of the electromagnetic wave blocking roller 4. Fig. 9A and Fig. 9B, the conductive plates 5A and 5B are conductive parts that are conductively connected to the metal base 103 and are in surface contact with the circumferential surface of the electromagnetic wave blocking roller 4. The electromagnetic wave blocking roller 4 is electrically connected to the metal base 103 via the conductive plate 5A or 5B.

[0047] As in Fig. As shown in Figure 9A, the conductive plate 5A is an electrically conductive, plate-shaped element with a curved surface, one end of which is attached to the rear of the metal base 103. The curvature of the curved area of ​​the conductive plate 5A is shaped to match the curvature of the electromagnetic wave-blocking roller 4, and the conductive plate 5A and the electromagnetic wave-blocking roller 4 are in surface contact.

[0048] As in Fig. As shown in Figure 9B, the conductive plate 5B is an electrically conductive, block-shaped element with a curved surface, one end of which is attached to the rear of the metal base 103. Similar to the conductive plate 5A, the curvature of the curved area of ​​the conductive plate 5B is shaped to match the curvature of the electromagnetic wave-blocking rollers 4, and the conductive plate 5B and the electromagnetic wave-blocking roller 4 make surface contact.

[0049] In this way, the conductive plates 5A and 5B do not have conductive structures with electrically conductive rotating shafts, but instead establish surface contact with the circumferential surface of the electromagnetic wave-blocking roller 4. This allows the conductive plates 5A and 5B to reduce the impedance between themselves and the electromagnetic wave-blocking roller 4, enabling a more robust ground connection. Furthermore, the conductive plates 5A and 5B can maintain frictionless contact even when the electromagnetic wave-blocking roller 4 is rotating.

[0050] While the conductive plates 5A and 5B are attached to the electromagnetic wave blocking roller 4 in the cases shown, the conductive plates 5A or 5B can be attached to any sub-roll of the aforementioned electromagnetic wave blocking roller 4A or together establish a surface contact with circumferential areas of the plurality of sub-rolls.

[0051] As mentioned above, the electromagnetic wave blocking structure 1 according to the first embodiment comprises: the electrically conductive flat belt 3, which is wound around the pair of parallel rollers 2 beneath the surface of the metal base 103 and is exposed through the opening 104 formed by the surface of the metal base 103, so that the tires 101 and 102 of the vehicle 100 can be placed on it; and the electrically conductive electromagnetic wave blocking roller 4, which is arranged between the metal base 103 and the flat belt 3 at the opening 104, is conductively connected to the metal base 103, and is in contact with the flat belt 3 in order to rotate along with the movement of the flat belt 3. This places the flat belt 3 at the same potential as the metal base 103.This allows the electromagnetic wave blocking structure 1 to block unnecessary electromagnetic waves that propagate through the opening 104 formed in the metal base 103 of the electromagnetically reflection-free space.

[0052] In the electromagnetic wave blocking structure 1 according to the first embodiment, the electromagnetic wave blocking roller 4 is arranged at the opening 104 either at the area 104A where the flat belt emerges from under the base, or at the area 104B where the flat belt runs under the base, or at both areas, and is in contact with the flat belt 3 in the width direction of the flat belt 3. This allows the electromagnetic wave blocking structure 1 to block electromagnetic waves propagating between the flat belt 3 and the metal base 103 at the opening 104.

[0053] In the electromagnetic wave blocking structure 1 according to the first embodiment, the electromagnetic wave blocking roller 4 is a single roller extending in the width direction of the flat belt 3. This makes it possible to reliably establish a conductive connection between the electromagnetic wave blocking roller 4 and the flat belt 3.

[0054] In the electromagnetic wave blocking structure 1 according to the first embodiment, the electromagnetic wave blocking roller 4A is a plurality of sub-rollers arranged in the width direction of the flat belt 3 and rotating coaxially. This makes it possible to reliably establish a conductive connection between the electromagnetic wave blocking roller 4A and the flat belt 3.

[0055] The electromagnetic wave blocking structure 1 according to the first embodiment comprises one or more metal sections 6 that are provided along the longitudinal direction of the flat belt 3, cross the opening 104 in the lateral direction of the flat belt 3, and are electrically connected. By inserting a plurality of metal sections 6, it is possible to block electromagnetic waves that propagate between the lateral sides of the flat belt 3 and the metal base 103.

[0056] In the electromagnetic wave blocking structure 1 according to the first embodiment, the electromagnetic wave blocking roller is one or more side surface rollers 7 and 8, which are provided between the side surfaces of the flat belt 3 and the metal base 103 at the opening 104. By including the side surface rollers, it is possible to block electromagnetic waves that propagate between the side surfaces of the flat belt 3 and the metal base 103.

[0057] The electromagnetic wave blocking structure 1 according to the first embodiment comprises the conductive plate 5A or 5B, which is conductively connected to the metal base 103 and establishes surface contact with the circumferential surface of the electromagnetic wave blocking roller 4 or 4A. The electromagnetic wave blocking roller 4 or 4A is electrically connected to the metal base 103 via the conductive plate 5A or 5B.

[0058] By inserting the conductive plate 5A or 5B, it is possible to establish a reliable conductive connection between the electromagnetic wave blocking roller 4 or 4A and the metal base 103.

[0059] Since the chassis dynamometer system 200 according to the first embodiment includes the electromagnetic wave blocking structure 1, it is possible to block unnecessary electromagnetic waves that propagate through the opening 104 formed in the metal floor 103 of the electromagnetically reflection-free space. Second embodiment.

[0060] Fig. Figure 10 is a side view schematically showing a chassis dynamometer system 200A according to a second embodiment. While the respective chain links contained in each chain 11 are in Fig. Although 10 are shown separately, adjacent chain links are actually connected to each other by pins and projections. Fig. 10. The chassis dynamometer system 200A is a system that can perform simulations of a vehicle 100 on the surface of a metal floor 103. For example, the chassis dynamometer system 200A is provided in an electromagnetically reflection-free room with a metal floor 103. As in Fig. As shown in Figure 10, the chassis dynamometer system 200A comprises an electromagnetic wave blocking structure 1A located under the metal floor 103.

[0061] The electromagnetic wave blocking structure 1A comprises: chains 11, which are intended for the front tires 101 and rear tires 102 of the vehicle 100, which is a vehicle to be tested, and which are wound around a pair of rollers 2A; and an electromagnetic wave blocking roller 4B. An opening is formed in the metal base 103, and the chains 11 wound around the rollers 2 are exposed through the opening to the interior, to the electromagnetically reflection-free space.

[0062] It should be noted that the rollers are 2A rollers, which are at least electrically conductive on their surfaces.

[0063] Furthermore, as in Fig. Figure 10 shows the pair of rollers 2A arranged parallel beneath the metal base 103. For this reason, the flat areas of the chains 11 wound around the rollers 2A run almost parallel to the surface of the metal base 103. The vehicle 100 is positioned in the electromagnetically reflection-free space in such a way that the tires 101 and 102 are placed on the areas formed by the chains 11.

[0064] For example, if the tires 101 point in the direction of the Fig. When the rollers 2A are rotated in the direction indicated by the arrow 10, they rotate in the opposite direction to the tires 101, and the chains 11 wound around the rollers 2A also rotate accordingly. In this way, the chassis dynamometer system 200A is able to simulate conditions that closely approximate the actual driving of the vehicle 100 when the tires 101 and 102 of the vehicle 100 are placed on the chains 11.

[0065] It should be noted that, although in Fig. 10. Although no illustration is shown, a drive control device for rotating the chains 11, i.e., for rotating the rollers 2A, is located under the metal base 103; furthermore, a device to be tested, which is subjected to an EMC test, is mounted on the vehicle 100. Electronic circuits are attached to the drive control device and the device to be tested and can generate unnecessary electromagnetic waves as sources of interference.

[0066] On the other hand, as mentioned above, the opening for exposing the chains 11 is formed in the metal base 103 of the electromagnetically reflection-free space. It is necessary to provide gaps between the chains 11 and the opening in the metal base 103 to prevent the metal base 103 from obstructing the rotation of the chains 11. For this reason, there is a possibility that electromagnetic interference generated in the interference sources could be transmitted through the gaps into the interior and exterior of the electromagnetically reflection-free space.

[0067] To solve this problem, the electromagnetic wave blocking structure 1A is provided with the electrically conductive electromagnetic wave blocking roller 4B between the metal base 103 and a circumferential area of ​​a roller 2A at the opening of the metal base 103. As, for example, in Fig. As shown in Figure 10, the electromagnetic wave blocking roller 4B is arranged at the opening of the metal base 103 either in an area 104A where the chains 11 emerge from under the base, or in an area 104B where the chains 11 lead under the base, or in both areas.

[0068] The electromagnetic wave blocking roller 4B is conductively connected to the metal base 103 and arranged such that its circumferential surface is in contact with the electrically conductive circumferential area of ​​the roller 2A. The electromagnetic wave blocking roller 4B is configured to rotate together with the movement of the chains 11. For example, it rotates in Fig. 10. Due to the clockwise rotation of rollers 2B, chains 11 also rotate clockwise. The electromagnetic wave-blocking roller 4B, which is in contact with the circumferential area of ​​roller 2A, rotates counterclockwise along with the rotation of chains 11.

[0069] Each chain 11 comprises a multitude of chain links connected to one another via pins and projections, the individual chain links being electrically conductive. Furthermore, as mentioned above, the rollers 2A are electrically conductive, and the electromagnetic wave blocking roller 4B is an electrically conductive element conductively connected to the metal base 103. Therefore, the chains 11 are electrically connected to the metal base 103 via the electromagnetic wave blocking roller 4B through the circumferential area of ​​the roller 2A, and are at the same potential (ground potential) as the metal base 103. In this way, the chains 11 function as large ground surfaces arranged at the opening formed in the metal base 103. Accordingly, it is possible to block electromagnetic waves propagating through the opening.

[0070] Furthermore, the electromagnetic wave blocking roller 4B remains in contact with the circumferential area of ​​roller 2A by rotating along with the rotation of the chains 11, even when the chains 11 are rotating. For this reason, the electromagnetic wave blocking structure 1 can electrically connect the chains 11 to the metal base 103 independently of the rotation of the chains 11.

[0071] Since the electromagnetic wave blocking roller 4B rotates while remaining in contact with the roller 2A, the advantageous effect can also be achieved that it is less susceptible to wear than a design in which metal parts are simply brought into contact with the rotating roller 2A.

[0072] Next, an EMC test using an electromagnetically reflection-free chamber, including the chassis dynamometer system 200, is described. The chassis dynamometer system 200A is also capable of performing an EMC test on the vehicle 100 by placing it in the Fig. 2A and Fig. The electromagnetically reflection-free space 300 shown in Figure 2B is introduced. Since the EMC test aims to accurately measure only the electromagnetic waves emanating from the vehicle 100, electromagnetic interference from sources other than the vehicle 100 must be excluded.

[0073] Since the electromagnetic wave blocking structure 1A can shield electromagnetic interference through the opening in the bottom of the electromagnetic reflection-free space 300, it is possible to improve the accuracy of the aforementioned EMC test.

[0074] Next, the electromagnetic wave blocking structure 1A will be explained in detail.

[0075] Fig. Figure 11 is a side view that schematically illustrates the electromagnetic wave blocking structure 1A. Fig. Figure 11 shows the electromagnetic wave blocking structure 1A, which is provided at the area 104A where the chains 11 emerge from under the base at an opening 104 in the metal base 103. The electromagnetic wave blocking roller 4B is an electrically conductive roller located between the metal base 103 and the roller 2A at the opening 104, conductively connected to the metal base 103 and in contact with the roller 2A to rotate along with the movement of the chains 11.

[0076] For example, the electromagnetic wave blocking roller 4B is attached to the rear of the metal base 103 by a support element 5. The support element 5 is a metallic element. One end of the support element 5 is attached to the rear of the metal base 103, and the other end of the support element 5 is provided with an electrically conductive rotating shaft. The electromagnetic wave blocking roller 4B rotates around the rotating shaft and is electrically connected to the metal base 103 via the rotating shaft and the support element 5.

[0077] Furthermore, the height h of the support element 5 is designed such that a part of the circumferential surface of the electromagnetic wave blocking roller 4B is positioned so that this part touches the circumferential surface of the roller 2A.

[0078] Fig. Figure 12 is a top view schematically representing the electromagnetic wave blocking structure 1A, and shows the metal base 103 as transparent for the sake of simplicity in order to make the structure under the base visible.

[0079] Fig. Figure 13A is a front view schematically representing a roller 2A of the electromagnetic wave blocking structure 1A, and shows a state in which the chains 11 are wound around the roller 2A. Fig. Figure 13B is a front view schematically representing the roller 2A of the electromagnetic wave blocking structure 1A, and shows a state in which the chains 11 are away from the roller 2A.

[0080] Fig. Figure 14A is a front view schematically representing the electromagnetic wave blocking structure 1A, showing a state in which the chains 11 are wound around the roller 2A. Fig. Figure 14B is a front view schematically representing the electromagnetic wave blocking structure 1A, and shows a state in which the chains 11 are away from the roller 2A.

[0081] While the respective chain links, which are contained in each chain of 11, are in the Fig. 11, Fig. 12, Fig. 13A and Fig. In 14A, where the links of the chain are shown separately, adjacent chain links are actually connected to each other by pins and projections.

[0082] As in the Fig. 12, Fig. 13 and Fig. As shown in Figure 14, roller 2A acts as a drive wheel that drives the chains 11. For example, although in the Fig. 13B and Fig. 14B, where no illustration is shown, gears for driving the chains 11 are formed on areas adjacent to circumferential areas 3A of the roller 2A and around which the chains 11 are wound. While in the Fig. 12, Fig. 13 and Fig. 14 three chains 11 are wound around a pair of rollers 2A, the number of wound chains can also be one.

[0083] Furthermore, the electromagnetic wave blocking roller 4B consists of a plurality of electrically conductive sub-rollers arranged between the metal base 103 and the circumferential areas 3A at the opening 104, conductively connected to the metal base 103 and in contact with the circumferential areas 3A of the rollers 2A to rotate together with the movement of the chains 11.

[0084] The electromagnetic wave blocking roller 4B, comprising a multitude of sub-rolls, blocks the gap between the chains 11 and the metal base 103 in the latitude direction of the chains 11. Accordingly, it is possible to block unwanted electromagnetic waves propagating through the gap. It should be noted that the distance between the adjacent sub-rolls in the electromagnetic wave blocking roller 4B is a region that is non-conductively connected to the metal base 103. Therefore, the distance is set to prevent the escape of electromagnetic waves with a predetermined frequency. Electromagnetic waves with frequencies higher than the frequency at which the distance d corresponds to half a wavelength are more likely to escape. For example, if the upper frequency limit tolerated in the electromagnetic reflection-free space 300 is 10 GHz, then half a wavelength is 1.5 cm.Accordingly, the distance between the individual rollers is reduced to less than 1.5 cm.

[0085] In other words, reducing the distance to less than 1.5 cm decreases the probability of electromagnetic waves with frequencies of 10 GHz or less escaping. It should be noted that the electromagnetic interference generated underground is low and of such a level that its escape from the distance is not a problem, so the distance can be increased.

[0086] The flat belt 3 shown in the first embodiment comprises rubber, urethane, or the like. Therefore, lengthening the flat belt 3 to adapt it to the wheelbase of the vehicle 100 makes the flat belt 3 more susceptible to deflection due to its elasticity. In this case, the degree of deflection can be reduced by increasing the width of the flat belt 3; however, this undesirably increases the exposed area for the chassis dynamometer system 200 by a corresponding amount.

[0087] In contrast, with the chains 11, it is possible to change the overall length of the chains 11 in increments, with each increment corresponding to the length of a chain link, by adjusting the number of chain links to be used. This has the advantage that the chains 11 can easily be configured so that their length corresponds to the size of the electromagnetically reflection-free space 300.

[0088] It should be noted that in the case shown, the electromagnetic wave blocking roller 4B is provided at the area 104A where the chains 11 emerge from under the floor, but the electromagnetic wave blocking roller 4B can also be provided at the area 104B where the chains 11 lead under the floor.

[0089] By providing the electromagnetic wave blocking structure 1A in these areas, it is possible to reliably block unwanted electromagnetic waves. Furthermore, the electromagnetic wave blocking structure 1A can be provided for all tires of the vehicle 100.

[0090] Furthermore, the electromagnetic wave blocking roller 4B can be a single roller extending in the width direction of the flat belt 3. For example, the electromagnetic wave blocking roller 4B can be configured as a single roller by providing concave areas on the roller's circumferential surface to avoid interference with the chains 11. The single electromagnetic wave blocking roller 4B blocks the gap between the chains 11 and the metal base 103 in the width direction of the chains 11. Accordingly, it is possible to block unwanted electromagnetic waves propagating through the gap.

[0091] Furthermore, the in the Fig. 5 and Fig. The metal sub-areas 6 shown are provided on the electromagnetic wave blocking structure 1A.

[0092] The electromagnetic wave blocking structure 1 according to the first embodiment comprises one or more metal sections 6 arranged along the longitudinal direction of the chains 11, crossing the opening 104 in the lateral direction of the chains 11, and electrically connected. Since the metal sections 6 are electrically connected to the metal base 103 at ground potential, the metal sections 6 function as base surfaces. While the metal sections 6 are assumed to be plate-shaped elements, they can also be metal rods. By providing a plurality of metal sections 6 at the opening 104, it is possible to block the opening 104 and cut off unwanted electromagnetic waves propagating through the opening 104, regardless of the rotation of the chains 11.

[0093] In the electromagnetic wave blocking structure 1A, the distance between the plurality of metal part sections 6 arranged at the opening 104 is set such that the escape of electromagnetic waves with a predetermined frequency is prevented. Electromagnetic waves with frequencies higher than the frequency at which this distance corresponds to half a wavelength are more likely to escape. For example, if the upper frequency limit tolerated in the electromagnetic reflection-free space 300 is 10 GHz, half a wavelength is 1.5 cm. Accordingly, the distance between the adjacent metal part sections 6 is reduced to less than 1.5 cm. In other words, by reducing the distance to less than 1.5 cm, the probability of electromagnetic waves with frequencies of 10 GHz or less escaping is reduced.It should be noted that the distance can be increased if the electromagnetic interference generated under the ground is low and the escape of the electromagnetic interference from the distance is not a problem.

[0094] Furthermore, the in Fig. The 7 side surface rollers shown are attached to the electromagnetic wave blocking structure 1A.

[0095] That is, the electromagnetic wave blocking roller 4B blocks one or more side surface rollers 7 or 8 that are provided between the side surfaces of the chains 11 and the metal base 103 at the opening 104.

[0096] As shown in the drawing above in Fig. As shown in Figure 7, a side-surface roller 7 is an electrically conductive roller that rotates around a rotating shaft provided directly on the metal base 103. The side-surface roller 7 electrically connects a chain 11 and the metal base 103 by making contact with the chain 11 at a thick section of the chain 11.

[0097] Furthermore, as shown in the drawing below in Fig. Figure 7 shows a side-surface roller 8, an electrically conductive roller freely rotatable on a support element 9, which is attached to an end face of the opening 104. The support element 9 is a metallic element. One end of the support element 9 is attached to the rear of the metal base 104, and the other end of the support element 9 is provided with an electrically conductive rotating shaft. The side-surface roller 8 rotates around the rotating shaft and is electrically connected to the metal base 103 via the rotating shaft and the support element 9.

[0098] Similar to the side surface roller 7, the side surface roller 8 also establishes an electrical connection between a chain 11 and the metal base 103 by making contact with the chain 11 at a thick area of ​​the chain 11.

[0099] The side surface rollers 7 or 8 make it possible to suppress unnecessary electromagnetic waves that propagate through the gaps between the side surfaces of the chains 11 and the metal base 103.

[0100] Furthermore, the in Fig. 9A and Fig. The conductive plates 5A and 5B shown in Figure 9B are attached to the electromagnetic wave blocking structure 1A. The conductive plates 5A and 5B are conductively connected to the metal base 103 and are in surface contact with the circumferential surface of the electromagnetic wave blocking roller 4B. The electromagnetic wave blocking roller 4B is electrically connected to the metal base 103 via the conductive plate 5A or 5B.

[0101] As in Fig. As shown in Figure 9A, the conductive plate 5A is an electrically conductive, plate-shaped element with a curved surface, one end of which is attached to the rear of the metal base 103. The curvature of the curved part of the conductive plate 5A is shaped to match the curvature of the electromagnetic wave-blocking roller 4B, and the conductive plate 5A and the electromagnetic wave-blocking roller 4B are in surface contact.

[0102] As in Fig. As shown in Figure 9B, the conductive plate 5B is an electrically conductive, block-shaped element with a curved surface, one end of which is attached to the rear of the metal base 103. Similar to the conductive plate 5A, the curvature of the curved area of ​​the conductive plate 5B is shaped to match the curvature of the electromagnetic wave-blocking roller 4B, and the conductive plate 5B and the electromagnetic wave-blocking roller 4B make surface contact.

[0103] In this way, the conductive plates 5A and 5B do not have conductive structures using electrically conductive rotating shafts, but instead establish surface contact with the circumferential surface of the electromagnetic wave blocking roller 4B. This allows the conductive plates 5A and 5B to reduce the impedance between themselves and the electromagnetic wave blocking roller 4B, enabling a more robust ground connection. Furthermore, the conductive plates 5A and 5B can maintain a frictionless contact state even when the electromagnetic wave blocking roller 4B is rotating.

[0104] As mentioned above, the electromagnetic wave-blocking structure 1A according to the second embodiment comprises: the chains 11 wound around the pair of rollers 2A arranged parallel beneath the surface of the metal base 103 and exposed through the opening 104 formed in the metal base 103 in such a way that the tires 101 and 102 of the vehicle 100 are placed on them; the electrically conductive circumferential areas 3A provided on the circumferential surface of one roller or the circumferential surfaces of both rollers of the roller pair 2A; and the electrically conductive electromagnetic wave-blocking roller 4B, arranged between the metal base 103 and the circumferential areas 3A at the opening 104, conductively connected to the metal base 103 and in contact with the circumferential areas 3A to rotate together with the movement of the chains 11.This allows the electromagnetic wave blocking structure 1A to block electromagnetic waves that propagate between the circumferential areas 3A of the rollers 2A and the metal base 103 of the chassis dynamometer system 200 at the opening 104.

[0105] In the electromagnetic wave blocking structure 1A according to the second embodiment, the electromagnetic wave blocking roller 4B is arranged at the opening 104 either at the region 104A where the chains 11 emerge from under the base, or at the region 104B where the chains 11 enter under the base, or at both regions. This allows the electromagnetic wave blocking structure 1A to block electromagnetic waves propagating between the circumferential regions 3A and the metal base 103 at the opening 104.

[0106] In the electromagnetic wave blocking structure 1A according to the second embodiment, the electromagnetic wave blocking roller 4B is a single roller extending in the width direction of the rollers 2A around which the chains 11 are wound. This makes it possible to establish a reliable conductive connection between the electromagnetic wave blocking roller 4B and the circumferential areas 3A.

[0107] In the electromagnetic wave blocking structure 1A according to the second embodiment, the electromagnetic wave blocking roller 4B is a plurality of sub-rolls arranged in the lateral direction of the rollers 2A around which the chains 11 are wound and which rotate coaxially. This makes it possible to establish a reliable conductive connection between the electromagnetic wave blocking roller 4B and the circumferential areas 3A.

[0108] The electromagnetic wave blocking structure 1A according to the second embodiment comprises one or more metal sections 6 arranged along the longitudinal direction of the chains 11, passing through the opening 104 in the lateral direction of the chains 11, and being electrically connected. The plurality of metal sections 6 makes it possible to block electromagnetic waves propagating through the opening 104.

[0109] The electromagnetic wave blocking structure 1A according to the second embodiment comprises the conductive plate 5A or 5B, which is conductively connected to the metal base 103 and establishes surface contact with the circumferential surface of the electromagnetic wave blocking roller 4B. The electromagnetic wave blocking roller 4B is electrically connected to the metal base 103 via the conductive plate 5A or 5B. The surface contact between the conductive plate 5A or 5B and the circumferential areas 3A of the electromagnetic wave blocking roller 4B increases the contact area between them. This enables the electromagnetic wave blocking structure 1A to reliably establish a conductive connection between the electromagnetic wave blocking roller 4B and the metal base 103.

[0110] In the electromagnetic wave blocking structure 1A according to the second embodiment, the chains 11 are electrically conductive. By connecting the electrically conductive chains 11 to the metal base 103, the base area, including the opening 104, becomes a large mass. Accordingly, it is possible to block unwanted electromagnetic waves that propagate through the opening 104 into the interior and exterior of the electromagnetically reflection-free space.

[0111] In the electromagnetic wave blocking structure 1A according to the second embodiment, the electromagnetic wave blocking roller 4B is one or more side surface rollers provided between the side surfaces of the chains 11 and the metal base 103 at the opening 104. This makes it possible to establish a reliable conductive connection between the electromagnetic wave blocking roller 4B and the chains 11.

[0112] Since the chassis dynamometer system 200A according to the second embodiment contains the electromagnetic wave blocking structure 1A, it is possible to block unnecessary electromagnetic waves that propagate through the opening 104 in the metal floor 103 of the electromagnetically reflection-free space.

[0113] It should be noted that a combination of the respective embodiments, a modification of each component in each embodiment, or the omission of each component in each embodiment is possible. INDUSTRIAL APPLICABILITY

[0114] For example, the electromagnetic wave blocking structures according to the present disclosure can be used for a chassis dynamometer system arranged in an electromagnetically reflection-free space. REFERENCE MARK LIST

[0115] 1, 1A: electromagnetic wave blocking structure; 2, 2A, 2B: roller; 3: flat belt; 3A: circumferential area; 4, 4A, 4B: electromagnetic wave blocking roller; 5, 9: support element; 5A, 5B: conductive plate; 6: metal part area; 7, 8: side surface roller; 10: rotating shaft; 11: chain; 100: vehicle; 101, 102: tire; 103: metal base; 104: opening; 104A, 104B: part; 200, 200A: chassis dynamometer system; 300: electromagnetic reflection-free space; 301: antenna mast; 302: receiving antenna QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP-2011-162912-A

[0005]

Claims

[1] Electromagnetic wave blocking structure included in a chassis dynamometer system capable of performing a simulation of a vehicle over a metal floor, the electromagnetic wave blocking structure comprising: an electrically conductive flat belt wound around a pair of rollers arranged parallel beneath the metal floor and exposed through an opening in the surface of the metal floor in such a way that a tire of the vehicle is mounted on it; and an electrically conductive electromagnetic wave blocking roller, which is arranged between the metal base and the flat belt at the opening, is conductively connected to the metal base and is in contact with the flat belt in order to rotate together with the movement of the flat belt. [2] Electromagnetic wave blocking structure according to claim 1, wherein the electromagnetic wave blocking roller is arranged at the opening either in a region where the flat belt emerges from under a base, or in a region where the flat belt runs under the base, or in both regions, and is in contact with the flat belt in the width direction of the flat belt. [3] Electromagnetic wave blocking structure according to claim 2, wherein the electromagnetic wave blocking roller is a single roller extending in the width direction of the flat belt. [4] Electromagnetic wave blocking structure according to claim 2, wherein the electromagnetic wave blocking roller is designed as a plurality of sub-rolls arranged in the width direction of the flat belt and rotating coaxially. [5] Electromagnetic wave blocking structure according to any one of claims 1 to 4, comprising one or more metal sections which are provided along a longitudinal direction of the flat belt, cross the opening in a lateral direction of the flat belt and are electrically connected. [6] Electromagnetic wave blocking structure according to any one of claims 1 to 4, wherein the electromagnetic wave blocking roller is designed as one or more side surface rollers provided between a side surface of the flat belt and the metal base at the opening. [7] Electromagnetic wave blocking structure according to any one of claims 1 to 6, comprising a conductive area which is conductively connected to the metal base and establishes surface contact with a circumferential surface of the electromagnetic wave blocking roller, wherein the electromagnetic wave blocking roller is electrically connected to the metal base via the conductive area. [8] Electromagnetic wave blocking structure included in a chassis dynamometer system capable of performing a simulation of a vehicle over a metal floor, the electromagnetic wave blocking structure comprising: a chain wound around a pair of rollers arranged parallel under the metal floor and exposed through an opening in the surface of the metal floor, allowing a tire of the vehicle to be placed on it; an electrically conductive circumferential part provided on a circumferential surface of a roller or on the circumferential surfaces of both rollers of a pair of rollers; and an electrically conductive electromagnetic wave blocking roller, which is arranged between the metal base and the flat belt at the opening, is conductively connected to the metal base and is in contact with the circumferential area to rotate together with the movement of the chain. [9] Electromagnetic wave blocking structure according to claim 8, wherein the electromagnetic wave blocking roller is arranged at the opening either in a region where the chain emerges from under a floor, or in a region where the chain runs under the floor, or in both regions. [10] Electromagnetic wave blocking structure according to claim 9, wherein the electromagnetic wave blocking roller is a single roller extending in the width direction of the rollers around which the chain is wound. [11] Electromagnetic wave blocking structure according to claim 9, wherein the electromagnetic wave blocking roller is designed as a plurality of sub-rolls arranged in the width direction of the rollers around which the chain is wound and rotate coaxially. [12] Electromagnetic wave blocking structure according to any one of claims 8 to 11, comprising one or more metal part areas which are provided along a longitudinal direction of the chain, cross the opening in a lateral direction of the chain and are electrically connected. [13] Electromagnetic wave blocking structure according to any one of claims 8 to 12, comprising a conductive area which is conductively connected to the surface of the metal base and establishes surface contact with a circumferential surface of the electromagnetic wave blocking roller, wherein the electromagnetic wave blocking roller is electrically connected to the metal base via the conductive area. [14] Electromagnetic wave blocking structure according to any one of claims 8 to 13, wherein the chain is electrically conductive. [15] Electromagnetic wave blocking structure according to claim 14, wherein the electromagnetic wave blocking roller is designed as one or more side surface rollers provided between a side surface of the chain and the metal base at the opening. [16] Chassis dynamometer system with the electromagnetic wave blocking structure according to any one of claims 1 to 15.

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