Chassis dynamometer and method for designing roller in chassis dynamometer

Abstract

The objective of the present disclosure is to provide a chassis dynamometer capable of restraining a vehicle without requiring human intervention during a vehicle driving test. A side roller (3L (31)), which is a left side roller, presses a restraining roller (33) from the right side against a tire (6L), which is a left tire, to restrain the movement of the tire (6L) in the rightward direction. A side roller (3R), which is a right side roller, presses a restraining roller (33) from the left side against a tire (6R), which is a right tire, to restrain the movement of the tire (6R) in the leftward direction. The restraining roller (33) of the side roller (3L) is in contact with a lower region (6a) on the inner side of the tire (6L) and rotates in conjunction with the rotation of the tire (6L). The restraining roller (33) of the side roller (3R) is in contact with a lower region (6a) on the inner side of the tire (6R) and rotates in conjunction with the rotation of the tire (6R).

Description

Chassis dynamometer and roller design method for chassis dynamometer

[0001] The present disclosure relates to a chassis dynamometer used for various running tests of a vehicle, and in particular to a vehicle fixing function.

[0002] A chassis dynamometer has conventionally been used when conducting running tests of vehicles (automobiles), and includes a roller device as a main component.

[0003] In order to carry out various running tests involving steering operations of a vehicle, it is necessary to securely fasten the vehicle. A conventional chassis dynamometer in which a vehicle is secured is disclosed in, for example, Patent Document 1.

[0004] In the chassis dynamometer disclosed in Patent Document 1, a vehicle is secured in a predetermined position as a preparatory process prior to a running test of the vehicle. Note that "vehicle securing" refers to attaching a securing jig such as a vehicle securing rope to the vehicle to secure the vehicle.

[0005] Japanese Patent Application Laid-Open No. 2019-203869

[0006] As described above, conventional chassis dynamometers are used for vehicle running tests (development tests), and therefore, when conducting a vehicle running test, it was necessary to manually set the vehicle restraints, which required time for setting.

[0007] When conducting vehicle running tests such as autonomous driving tests, the securing means of the rope chassis dynamometer, represented by the vehicle securing rope, must be of a minimal configuration in order to avoid false detections by the various on-board sensors installed in the vehicle.

[0008] Conventional lashing methods required removing vehicle parts (wheel nuts, towing hook covers, etc.) to install lashing jigs such as vehicle lashing ropes. Because the shape of the lashing joints required to install the lashing jigs differs depending on the vehicle model, there were many different types of lashing jigs required to accommodate the various vehicle models, which increased manufacturing costs.

[0009] The present disclosure aims to solve the above-mentioned problems and provide a chassis dynamometer that can restrain a vehicle without requiring human intervention during a vehicle running test.

[0010] The chassis dynamometer of the present disclosure is a chassis dynamometer that includes four mounting rollers on which four tires of a vehicle are mounted, and four side rollers that are provided corresponding to the four tires and that restrain lateral movement of the vehicle, the four tires including two sets of tire pairs, the two sets of tire pairs including a front wheel tire pair and a rear wheel tire pair, the two sets of tire pairs including a left tire and a right tire disposed on the left and right, respectively, the direction in which the left tire and the right tire face each other is defined as the lateral direction of the vehicle, and the left tire and the right tire each have an outer or inner side that contacts the The four side rollers are defined as contact sides, and the four side rollers include two pairs of side rollers corresponding to the two pairs of tires, and each of the two pairs of side rollers includes a left side roller that contacts the left tire on the contact side and applies a left tire restraining force to the left tire along a left tire restraining direction, and a right side roller that contacts the contact side of the right tire and applies a right tire restraining force to the right tire along a right tire restraining direction, and the left tire restraining direction is the direction from the left side roller toward the left tire, and the right tire restraining direction is the direction from the right side roller toward the right tire.

[0011] The chassis dynamometer of the present disclosure has four side rollers as permanent vehicle restraint means, so there is no need to set the four side rollers when conducting a vehicle running test. In other words, the chassis dynamometer of the present disclosure does not require manual work when restraining the vehicle.

[0012] The four side rollers include two pairs of side rollers, each of which is composed of the left side roller and the right side roller described above.

[0013] In each of the two pairs of side rollers, movement of the left tire in the direction opposite to the left tire restraining direction is restrained by the left tire restraining force of the left side roller, and movement of the right tire in the direction opposite to the right tire restraining direction is restrained by the right tire restraining force of the right side roller.

[0014] As a result, the chassis dynamometer of the present disclosure can accurately restrain the lateral movement of the vehicle without requiring the setting time of four side rollers, including two pairs of side rollers.

[0015] Additionally, in the chassis dynamometer of the present disclosure, the only objects that are directly restrained on the vehicle are the four tires, so the chassis dynamometer of the present disclosure can restrain the lateral movement of the vehicle with the same configuration even if the vehicle model is changed.

[0016] The objects, features, aspects, and advantages of the present disclosure will become more apparent from the following detailed description and the accompanying drawings.

[0017] 11 is an explanatory diagram showing a schematic overall configuration of a chassis dynamometer according to a first embodiment of the present disclosure; FIG. 12 is an explanatory diagram showing a schematic planar configuration of the chassis dynamometer according to the first embodiment; FIG. 13 is an explanatory diagram showing a schematic contact relationship between a side roller and a tire (first aspect); FIG. 14 is an explanatory diagram showing a schematic contact relationship between a side roller and a tire (second aspect); FIG. 15 is an explanatory diagram showing a schematic configuration of a side roller; FIG. 16 is an explanatory diagram showing a schematic configuration of a side roller; FIG. 17 is an explanatory diagram showing a schematic configuration of a side roller mounted on a swivel base; FIG. 18 is an explanatory diagram showing a schematic configuration of a side roller mounted on a swivel base; FIG. 10 is an explanatory diagram schematically showing a dynamic model of tire jump-out prevention conditions when a pair of jump-out prevention rollers is provided.

[0018] <First Embodiment> Fig. 1 is an explanatory diagram that schematically shows the overall configuration of a chassis dynamometer 1 according to a first embodiment of the present disclosure. Fig. 2 is an explanatory diagram that schematically shows the planar configuration of the chassis dynamometer 1. An XYZ Cartesian coordinate system is depicted in each of Figs. 1 and 2. In Figs. 1 and 2, the front of a vehicle 60 is the +Y direction, the rear is the -Y direction, the lateral direction of the vehicle 60 (vehicle width direction) is the X direction, and the height direction of the vehicle 60 is the +Z direction.

[0019] As shown in Figures 1 and 2, the chassis dynamometer 1 is equipped with four mounting rollers (20, 21) on which the four tires 6 of a vehicle 60 are mounted, and four side rollers 3 (3L, 3R) that are provided corresponding to the four tires 6 and that restrain the lateral movement of the vehicle 60. Figures 1 and 2 show two pairs of rollers 21 for the front wheels and two pairs of rollers 22 for the rear wheels as the four mounting rollers.

[0020] 2, the inner side roller 31 of the side rollers 3 (3L, 3R) in the first embodiment is shown by a solid line, and the outer side roller 32 of the second embodiment is shown by a dashed line. Also, in FIG. 1, only the outer side roller 32 of the second embodiment is shown as the side roller 3. The chassis dynamometer 1 of the first embodiment employs either the inner side roller 31 or the outer side roller 32 as the side roller 3.

[0021] The four tires 6 include two tire pairs, each including a front tire pair and a rear tire pair, each including a left tire 6L and a right tire 6R arranged on the left and right sides.

[0022] The floor surface 50 includes a front wheel area 51 and a rear wheel area 52, and two swivel bases 11 (11L, 11R) are provided in the front wheel area 51 of the floor surface 50. Two pairs of front wheel rollers 21 corresponding to the front wheel tire pair, two pairs of side rollers 3L and 3R, and two pairs of anti-jump-out rollers 4F and 4B are provided on the two swivel bases 11.

[0023] The two swivel bases 11 include swivel base 11L and swivel base 11R, and the front wheel roller pair 21 corresponding to tire 6L, which is the left tire on the front wheel side, the side roller 3L, and two pairs of anti-flyout rollers 4F and 4B are arranged to rotate together with the swivel base 11L.

[0024] On the other hand, the front wheel roller pair 21 corresponding to the right front tire RL, the side roller 3R, and the two pairs of anti-jump rollers 4F and 4B are arranged to rotate together with the swivel base 11R.

[0025] Two fixing bases 15 are provided in the rear wheel region 52. Two rear wheel roller pairs 22 corresponding to the rear wheel tire pair, two side roller pairs 3L and 3R, and two anti-jump roller pairs 4F and 4B are provided on the two fixing bases 15.

[0026] The two fixed bases 15 include fixed base 15L and fixed base 15R, and the rear wheel roller pair 22 corresponding to tire 6L, which is the left tire on the rear wheel side, the side roller 3L, and two pairs of anti-flyout rollers 4F and 4B are provided on fixed base 15L.

[0027] On the other hand, the rear wheel roller pair 22 corresponding to the right rear tire 6R, the side roller 3R, and the two pairs of anti-jump-out rollers 4F and 4B are provided on the fixed base 15R.

[0028] The X direction in which the tires 6L and 6R face each other is defined as the lateral direction of the vehicle 60, and the outer side (side surface (sidewall)) or inner side (side surface) of each of the tires 6L and 6R is defined as the contact side.

[0029] As described above, the four mounting rollers are composed of a pair of front wheel rollers 21 for mounting the front wheel tire pair and a pair of rear wheel rollers 22 for mounting the rear wheel tire pair.

[0030] The four side rollers 3 include two pairs of side rollers 3L and 3R corresponding to two pairs of tires (front wheel tire pair + rear wheel tire pair), and the two pairs of side rollers 3L and 3R serve as a fastening means for preventing lateral movement of the vehicle 60.

[0031] Each of the two side roller pairs 3L and 3R is composed of a side roller 3L and a side roller 3R. In the first embodiment, inner side rollers 31 are used as the side roller pairs 3L and 3R, and in the second embodiment, outer side rollers 32 are used as the side roller pairs 3L and 3R.

[0032] The left side roller 3L comes into contact with the left tire 6L on the contact side and applies a left tire restraining force to the tire 6L in the left tire restraining direction. When the side roller 3L is the inner side roller 31, the inner side (side surface) of the tire 6L is the contact side, and the left tire restraining force is in the left direction (+X direction). On the other hand, when the side roller 3L is the outer side roller 32, the outer side (side surface) of the tire 6L is the contact side, and the right tire restraining direction is in the right direction (-X direction).

[0033] The right-side side roller 3R contacts the tire 6R, which is the right tire, on its contact side and applies a right-tire restraining force to the tire 6R in the right-tire restraining direction. When the side roller 3R is the inner side roller 31, the inner side of the tire 6R is the contact side, and the left-tire restraining force is in the right direction (-X direction). On the other hand, when the side roller 3R is the outer side roller 32, the outer side of the tire 6R is the contact side, and the right-tire restraining direction is in the left direction (+X direction).

[0034] Thus, in each of the first and second aspects of the side roller 3, the left tire restraint direction is the direction from the side roller 3L, which is the left side roller, toward the tire 6L, which is the left tire, and the right tire restraint direction is the direction from the side roller 3R, which is the right side roller, toward the tire 6R.

[0035] 3 and 4 are explanatory diagrams that schematically show the contact relationship between the side rollers 3 (3L, 3R) and the tires 6 (6L, 6R), and Fig. 5 is an explanatory diagram that schematically shows the configuration of the side rollers 3. Each of Figs. 3 to 5 shows an XYZ Cartesian coordinate system.

[0036] As shown in Figures 3 and 4, the tires 6L and 6R are positioned symmetrically on either side of the vehicle center line CL. Figure 3 shows the case where the side roller 3 is the inner side roller 31 of the first embodiment, and Figure 4 shows the case where the side roller 3 is the outer side roller 32 of the second embodiment.

[0037] As shown in FIG. 5, the side roller 3 includes a restraining roller 33, a bearing 34, and a fixed shaft 35 as main components.

[0038] The fixed shaft 35 is erected along the Z direction, which is the height direction. The side rollers 3 (3L, 3R) provided on the front tire pair are provided on the swivel base 11, and the side rollers 3 provided on the rear tire pair are provided on the fixed base 15 (15L, 15R).

[0039] The bearing 34 is mounted on the upper part of the fixed shaft 35 so as to be rotatable around the fixed shaft 35 as a rotation axis. The restraining roller 33 has the bearing 34 therein and rotates integrally with the bearing 34.

[0040] The restraining roller 33 comes into contact with the lower region 6 a ( 6 b ) of the tire 6 on the contact side of the tire 6 , and rotates in conjunction with the rotation of the tire 6 .

[0041] (First Aspect) Hereinafter, a first aspect of the chassis dynamometer 1 employing inner side rollers 31 as the side rollers 3 will be described with reference to FIGS. 2, 3 and 5. FIG.

[0042] In the first mode of the chassis dynamometer 1, the contact side of the tire 6 is the inside of the tire 6, and the left tire restraining direction D3L for the tire 6L is to the left. Therefore, the side roller 3L (31) can press the restraining roller 33 against the lower region 6a of the tire 6L from the right side, thereby restraining the rightward movement of the tire 6L.

[0043] On the other hand, the right tire restraining direction D3R for the tire 6R is to the right. Therefore, the side roller 3R (31) can press the restraining roller 33 against the lower region 6a of the tire 6R from the left side, thereby restraining the leftward movement of the tire 6R.

[0044] 3, in the first mode of the chassis dynamometer 1, the restraining rollers 33 of the side rollers 3L contact the lower region 6a of the tire 6L on the inner side (-X direction side) of the tire 6L and rotate in conjunction with the rotation of the tire 6L. The tire 6L is rotating during the running test.

[0045] 3, in the first mode of the chassis dynamometer 1, the restraining roller 33 of the side roller 3R comes into contact with the lower region 6a of the tire 6R on the inner side (+X direction side) of the tire 6R, and rotates in conjunction with the rotation of the tire 6R. The tire 6R is rotating during the running test.

[0046] The driving of the vehicle 60 carried out as a driving test includes straight driving of the vehicle 60 and turning driving of the vehicle 60 in which the tires 6 are turned.

[0047] (Second Embodiment) Next, a second embodiment of the chassis dynamometer 1 employing outer side rollers 32 as the side rollers 3 will be described with reference to FIGS. 2, 4 and 5. FIG.

[0048] In the chassis dynamometer 1 of the second embodiment, the contact side of the tire 6 is on the outer side of the tire 6, and the left tire restraining direction D3LX for the tire 6L is to the right. Therefore, the side roller 3L (32) can press the restraining roller 33 against the lower region 6b of the tire 6L from the left side to restrain the leftward movement of the tire 6L.

[0049] On the other hand, the right tire restraining direction D3RX for the tire 6R is the leftward direction. Therefore, the side roller 3R (32) can press the restraining roller 33 against the lower region 6b of the tire 6R from the right side, thereby restraining the rightward movement of the tire 6R.

[0050] 4, in the second mode of the chassis dynamometer 1, the restraining rollers 33 of the side rollers 3L contact the lower region 6b of the tire 6L on the outer side (+X direction side) of the tire 6L and rotate in conjunction with the rotation of the tire 6L. The tire 6L is rotating during the running test.

[0051] 4, in the second mode of the chassis dynamometer 1, the restraining roller 33 of the side roller 3R comes into contact with the lower region 6b of the tire 6R on the outer side (−X direction side) of the tire 6R, and rotates in conjunction with the rotation of the tire 6R. The tire 6R is rotating during the running test.

[0052] (Effect (1)) Because the chassis dynamometer 1 of the first embodiment has four side rollers 3 (two pairs of side rollers 3L and 3R) as permanent fastening means for the vehicle 60, there is no need to reset the four side rollers 3 when conducting a running test of the vehicle 60. In other words, the chassis dynamometer 1 of the first embodiment does not require manual work when fastening the vehicle 60.

[0053] The four side rollers 3 include two pairs of side rollers 3L and 3R. Each of the two pairs of side rollers 3L and 3R is composed of the above-mentioned side roller 3L and side roller 3R.

[0054] In the first mode of the chassis dynamometer 1, in each of the two pairs of side rollers 3L (31) and 3R (31), movement of the tire 6L in the right direction (-X direction), which is the opposite direction of the left tire restraining direction D3L, is restrained by the left tire restraining force of the side roller 3L (31). Similarly, movement of the tire 6R in the left direction, which is the opposite direction of the right tire restraining direction D3R, is restrained by the right tire restraining force of the side roller 3R (31).

[0055] In the second mode of the chassis dynamometer 1, in each of the two pairs of side rollers 3L (32) and 3R (32), movement of the tire 6L in the left direction (+X direction), which is the opposite direction of the left tire restraining direction D3LX, is restrained by the left tire restraining force of the side roller 3L (32). Similarly, movement of the tire 6R in the right direction, which is the opposite direction of the right tire restraining direction D3RX, is restrained by the right tire restraining force of the side roller 3R (32).

[0056] In this way, in each of the first and second modes of the chassis dynamometer 1, movement of the tire 6L in the direction opposite to the left tire restraint direction is restrained by the left tire restraint force of the side roller 3L, and movement of the tire 6R in the direction opposite to the right tire restraint direction is restrained by the right tire restraint force of the side roller 3R.

[0057] As a result, the chassis dynamometer 1 of embodiment 1 can accurately restrain the lateral movement of the vehicle 60 by using four side rollers 3, including two pairs of side rollers 3L and 3R, thereby eliminating the setting time for the four side rollers 3, which serve as permanent fastening means.

[0058] Therefore, the chassis dynamometer 1 of the first embodiment shortens the takt time in vehicle production including running tests, and can also be used for running tests on completed vehicles on the production line.

[0059] Additionally, in the chassis dynamometer 1 of the first embodiment, only the four tires 6 (6L, 6R) of the vehicle 60 are directly restrained. Therefore, the chassis dynamometer 1 can restrain the lateral movement of the vehicle 60 with the same configuration even if the type of vehicle 60 is changed.

[0060] Specifically, since it is no longer necessary to manufacture lashing jigs with different fitting shapes depending on the vehicle model, the manufacturing costs required for lashing jigs can be reduced. Also, since the chassis dynamometer 1 of the first embodiment can restrain the vehicle 60 without removing parts (such as covers or wheel nuts) from the vehicle 60, the time required for setting up the lashing jigs can be saved.

[0061] The tread, which is the distance between the centers of the tires 6L and 6R of the vehicle 60, changes when the vehicle model is changed. However, after changing the vehicle model of the vehicle 60, by moving the roller base (the swivel base 11 or the fixed base 15) laterally to fit the changed vehicle tread, the positional relationship between the X coordinate of the tire center point C6 of the tires 6 (6L and 6R) and the X coordinate of the roller widthwise center can be made to match the state before the vehicle model change. Note that the "roller widthwise center" refers to the central position of each of the front wheel roller pairs 21 (rear wheel roller pairs 22) in the lateral direction (vehicle width direction; X direction). Furthermore, the roller base can be moved laterally using existing technology.

[0062] In this way, even if the vehicle model of the vehicle 60 is changed, the lateral positional relationship between the tire center point C6 of the tire 6 and the center of the roller width direction can always be set to be the same. Therefore, before and after the vehicle model of the vehicle 60 is changed, the side roller pairs 3L and 3R can be permanently arranged relatively easily so that each restraining roller 33 contacts the tire 6 (6L and 6R) at the contact point.

[0063] Contact with the tire 6 is made by the restraining rollers 33 of the side rollers 3. Since the restraining rollers 33 come into contact with the tire 6 in the lower region 6a (6b) of the tire 6 on the contact side of the tire 6, the four side rollers 3 are difficult to detect by various sensors equipped on the vehicle 60.

[0064] 6 is an explanatory diagram that schematically shows the installation positions of sensors on a vehicle 60. In the front of the vehicle 60, a camera, for example, is installed at installation position P1 in the upper region of the windshield, a millimeter-wave radar (for long-distance measurement), for example, is installed at installation position P2 included in the headlamps and front grille, a laser range finder, for example, is installed at installation positions P3 and P4 in the front bumper and its surrounding area, and a millimeter-wave radar (for long-distance measurement), for example, is installed at installation position P5 in the front fender and its surrounding area.

[0065] At the rear of the vehicle 60, a laser range finder, for example, is installed at installation position P6 on the rear bumper and its surrounding area, and a millimeter wave radar (for long-distance measurement), for example, is installed at installation position P7 on the rear fender and its surrounding area. Also, a global navigation satellite system (GNSS) and a high-precision gyro, for example, are installed at installation position P8 on the roof.

[0066] In this way, various sensors are installed at installation positions P1 to P8 of the vehicle 60, but since the restraining roller 33 of each of the four side rollers 3 is installed in such a manner that it contacts the lower region 6a (6b) of the tire 6 on the contact side of the tire 6, it is difficult to detect by the various sensors equipped at the above-mentioned installation positions P1 to P8 of the vehicle 60.

[0067] Therefore, since the four pairs of side rollers 3L and 3R for preventing lateral movement in the chassis dynamometer 1 of embodiment 1 are installed below the body of the vehicle 60 and near the tires 6, false detections by various sensors including the autonomous driving sensors used in driving tests can be avoided, making it possible to support autonomous driving tests of the vehicle 60.

[0068] In this way, when the chassis dynamometer 1 of the first embodiment is used to carry out a running test of the vehicle 60 using various sensors, the four side rollers do not have any adverse effects.

[0069] In addition, since the restraining rollers 33 of the side rollers 3 rotate in conjunction with the rotation of the tire 6, wear on the tire 6 can be minimized when the vehicle 60 is restrained by the four side rollers 3.

[0070] The above effects will be described in detail below. Because the side rollers 3 allow the restraining rollers 33 to rotate freely, the rotation speed of the restraining rollers 33 follows the rotation speed of the tire 6 that is in contact with the side rollers 3, and no speed difference occurs between the rotation speed of the tire 6 and the rotation speed of the restraining rollers 33. Therefore, wear on the tire 6 can be minimized.

[0071] In each of the two pairs of side rollers 3L and 3R of the first aspect of the chassis dynamometer 1, the movement of the tire 6L to the right is restrained by the restraining force for the left tire of the side roller 3L (31), which is the left side roller, and the movement of the tire 6R to the left is restrained by the restraining force for the right tire of the side roller 3R (31), which is the right side roller.

[0072] That is, in the first mode of the chassis dynamometer 1, lateral movement of the vehicle 60 to the left is restrained by the side rollers 3R (31) on the front and rear wheel sides, and lateral movement of the vehicle 60 to the right is restrained by the side rollers 3L (31) on the front and rear wheel sides.

[0073] As a result, the first aspect of the chassis dynamometer 1 of embodiment 1 can accurately restrain the lateral movement of 60 by using two pairs of side rollers 3L and 3R, which use inner side rollers 31.

[0074] In addition, since the restraining rollers 33 in the side roller pairs 3L and 3R of the first aspect contact the lower region 6a of the tire 6 inside the tire 6 (6L, 6R), the four side rollers 3 including the two side roller pairs 3L and 3R have the characteristic of being less detectable than in the second aspect by various sensors equipped on the vehicle 60.

[0075] In each of the two pairs of side rollers 3L and 3R of the second aspect of the chassis dynamometer 1, movement of the tire 6L to the left is restrained by the left tire restraining force of the side roller 3L (32), which is the left side roller, and movement of the tire 6R to the right is restrained by the right tire restraining force of the side roller 3R (32), which is the right side roller.

[0076] That is, in the second mode of the chassis dynamometer 1, lateral movement of the vehicle 60 to the left is restrained by the side rollers 3L (32) on the front and rear wheel sides, and lateral movement of the vehicle 60 to the right is restrained by the side rollers 3R (32) on the front and rear wheel sides.

[0077] As a result, the second aspect of the chassis dynamometer 1 of embodiment 1 can accurately restrain the lateral movement of the vehicle 60 by using two pairs of side rollers 3L and 3R, which employ outer side rollers 32.

[0078] (Turning Mechanism) Figure 7 is an explanatory diagram showing a schematic configuration of the turning mechanism 10 for the mounting rollers in the chassis dynamometer 1. An XYZ Cartesian coordinate system is shown in Figure 7. The turning mechanism 10 shown in the figure has a structure common to both the left roller turning mechanism (turning mechanism 10L) and the right roller turning mechanism (turning mechanism 10R). The turning mechanism 10L is a mechanism that turns the front wheel roller pair 21 on which the tire 6L of the front tire pair is mounted, and the turning mechanism 10R is a mechanism that turns the front wheel roller pair 21 on which the tire 6R of the front tire pair is mounted. Hereinafter, when the turning mechanisms 10L and 10R are collectively referred to, they will be referred to as the "turning mechanism 10."

[0079] As shown in FIG. 7, the front wheel roller pair 21 has a twin structure consisting of a front roller 21F and a rear roller 21B.

[0080] The swivel mechanism 10 includes, as main components, a swivel structure 131, a swivel bearing 134, a base 136, and a swivel motor 142. The swivel structure 131 includes a swivel base 11 and a swivel bed 135.

[0081] The rotation motor 142 is a geared motor whose speed can be controlled. A gear is attached to the tip of the rotation motor 142, and this gear meshes with a gear (not shown) attached to the outer periphery of the base 136. Therefore, the rotation of the rotation motor 142 causes the rotation bed 135 to rotate.

[0082] The swivel bearing 134 rotatably supports the swivel bed 135, and the swivel bed 135 is rotated by the power of the swivel motor 142 around the center of the swivel bearing 134. As the swivel bed 135 rotates, the swivel structure 131 including the swivel base 11 rotates. In this way, the swivel mechanism 10 has the swivel structure 131 that is rotated by the swivel motor 142. The uppermost part of the swivel structure 131 forms the swivel base 11.

[0083] In this way, the turning mechanism 10 performs a roller turning process that turns the turning structure 131 including the turning target rollers (front wheel roller pair 21). This roller turning process includes a left roller turning process and a right roller turning process, which will be described later.

[0084] The turning mechanism 10 can use an existing method to turn the turning structure 131 at a turning angle that matches the steering angle of the tire 6 during a running test of the vehicle 60.

[0085] 8 and 9 are explanatory diagrams schematically illustrating the side roller 3 mounted on the swivel base 11L and the surrounding configuration. An XYZ Cartesian coordinate system is depicted in each of Fig. 8 and Fig. 9. For ease of explanation, Fig. 8 and Fig. 9 omit the illustration of components of the swivel mechanism 10, except for the swivel base 11L.

[0086] As described above, the chassis dynamometer 1 of the first embodiment has the turning mechanism 10 (10L, 10R), and the turning mechanism 10 turns the two front wheel roller pairs 21 on which the front wheel tire pairs are placed.

[0087] That is, the four mounting rollers in the chassis dynamometer 1 include a left turning target roller and a right turning target roller on which one of the front tire pair and the rear tire pair of the vehicle 60 is mounted.

[0088] The left turning target roller is a front wheel roller pair 21 on which the tire 6L of the front wheel tire pair of the vehicle 60 is placed, and the right turning target roller is a front wheel roller pair 21 on which the tire 6R of the front wheel tire pair of the vehicle 60 is placed.

[0089] As such, the chassis dynamometer 1 of embodiment 1 has as its main components a turning mechanism 10L, which is a left-side roller turning mechanism that performs a left-side roller turning process to turn the left-side turning target roller, and a turning mechanism 10R, which is a right-side roller turning mechanism that performs a right-side roller turning process to turn the right-side turning target roller.

[0090] The swivel mechanism 10L includes a swivel table 11L as a left swivel table that swivels when the left roller swivel process is performed, and the swivel mechanism 10R includes a swivel table 11R as a right swivel table that swivels when the right roller swivel process is performed.

[0091] The side roller 3L mounted on the swivel base 11L and the side roller 3R mounted on the swivel base 11R are arranged symmetrically on the left and right sides with respect to the vehicle center line CL.

[0092] 8 and 9 show the front wheel roller pair 21, which is a left-side turning target roller on which the tire 6L of the front wheel tire pair is placed. Below, with reference to FIGS. 8 and 9, the side roller 3L mounted on the swivel base 11L will be described as a representative of the side rollers 3L and 3R.

[0093] The swivel mechanism 10L shown in FIG. 7 rotates the swivel base 11L in a swivel direction R2 around the swivel center C1 (C1L) as the central axis.

[0094] The side roller 3L shown in Figures 8 and 9 is a left side roller included in one of the two side roller pairs 3L and 3R, and rotates together with the swivel base 11L, which is the left swivel base. The side roller 3R, not shown in Figures 8 and 9, is a right side roller included in one of the two side roller pairs 3L and 3R, and rotates together with the swivel base 11R, which is the right swivel base.

[0095] In this way, one of the side rollers 3L of each of the two side roller pairs 3L and 3R serves as the left-side turning target side roller. Specifically, the side roller 3L corresponding to the tire 6L of the front tire pair serves as the left-side turning target side roller that turns together with the left-side turning table 11L.

[0096] Similarly, one of the side rollers 3R of each of the two side roller pairs 3L and 3R serves as the right-side turning target side roller. Specifically, the side roller 3R corresponding to the tire 6R of the front tire pair serves as the right-side turning target side roller that turns together with the right-side turning table 11R.

[0097] The side roller 3L, which is the left-side turning target side roller, includes a pressing cylinder 36 and a shaft mounting member 37 as main components in addition to the restraining roller 33, bearing 34, and fixed shaft 35 described with reference to Figure 5.

[0098] The shaft mounting member 37 of the side roller 3L is a left-side shaft mounting member that holds the fixed shaft 35 movably along the X direction, which is the left tire restraining direction D3L. The fixed shaft 35 maintains an upright state along the Z direction when it moves. The shaft mounting member 37 has a horizontal mounting portion 37a and a vertical mounting portion 37b, with the plate-shaped horizontal mounting portion 37a extending horizontally (X direction) and the plate-shaped vertical mounting portion 37b extending vertically (Z direction). The fixed shaft 35 penetrates the center of the horizontal mounting portion 37a and is attached to the horizontal mounting portion 37a in a vertically upright state.

[0099] The pressing cylinder 36 of the side roller 3L is fixed to the swivel base 11L, which is the left swivel base, and the vertical mounting portion 37b of the shaft mounting member 37 is fixed to the piston tip portion of the pressing cylinder 36. Therefore, the pressing cylinder 36 can apply a left tire pressing force to the shaft mounting member 37 along the X direction, which is the left tire restraining direction D3L.

[0100] In this way, by applying a left tire pressing force from the pressing cylinder 36 serving as a power source to the shaft mounting member 37, the side roller 3L can bring the lower region 6a of the tire 6L into contact with the restraining roller 33 on the inner side, which is the contact side, and apply a left tire pressing force to the tire 6L along the left tire restraining direction D3L. In other words, the left tire restraining force includes the left tire pressing force.

[0101] An opening is provided in the central region of the swivel base 11L so that the side roller 3L can smoothly apply the left tire restraining force to the tire 6L. The side roller 3L and the front wheel roller pair 21 for the tire 6L are provided independently of each other without any contact therebetween.

[0102] On the other hand, the right-side turning side roller 3R has a pressing cylinder 36 and a shaft mounting member 37 in addition to a restraining roller 33, a bearing 34, and a fixed shaft 35, similar to the side roller 3L.

[0103] The shaft mounting member 37 of the side roller 3R serves as a right shaft mounting member that holds the fixed shaft 35 movably along the −X direction, which is the right tire restraining direction D3R.

[0104] The pressing cylinder 36 of the side roller 3R is provided on the right-side rotating table 11R, and serves as a left-side pressing cylinder that applies a right tire pressing force to the shaft mounting member 37 along the −X direction, which is the right tire restraining direction D3R.

[0105] Therefore, by applying a right tire pressing force to the shaft mounting member 37 from the pressing cylinder 36 serving as a power source, the side roller 3R comes into contact with the tire 6R on the inner side, which is the contact side, and can apply a right tire restraining force to the tire 6R along the right tire restraining direction D3R. In other words, the right tire restraining force includes the right tire pressing force.

[0106] An opening is provided in the central region of the swivel base 11R so that the side roller 3R can smoothly apply the right tire restraining force to the tire 6R. The side roller 3R and the front wheel roller pair 21 for the tire 6R are provided independently of each other without any contact therebetween.

[0107] The two pairs of side rollers 3L and 3R corresponding to the pair of rear wheel tires are arranged in the same manner as the two pairs of side rollers 3L and 3R corresponding to the pair of front wheel tires, except that the swivel base 11 (11L, 11R) is replaced with a fixed base 15 (15L, 15R).

[0108] Furthermore, when the pair of side rollers 3L and 3R are in the second configuration, the pressing cylinder 36 and the shaft mounting member 37 are provided on the swivel base 11 or the fixed base 15, similarly to the first configuration described above.

[0109] That is, the side roller pair 3L (32) of the second aspect uses the pressing cylinder 36 as a power source to come into contact with the tire 6L on the outer side, which is the contact side, and can apply a left tire pressing force (restraining force) to the tire 6L along the left tire restraining direction D3LX. Also, the side roller pair 3R (32) of the second aspect uses the pressing cylinder 36 as a power source to come into contact with the tire 6R on the outer side, which is the contact side, and can apply a right tire pressing force (restraining force) to the tire 6R along the right tire restraining direction D3RX.

[0110] (Effect (Part 2)) The chassis dynamometer 1 of embodiment 1 has a side roller 3L that serves as a left-side rotating target side roller that rotates together with the left-side rotating base 11L, and a side roller 3R that serves as a right-side rotating target side roller that rotates together with the right-side rotating base 11R.

[0111] Therefore, the chassis dynamometer 1 of embodiment 1 can accurately restrain the lateral movement of the vehicle 60 even when performing the left roller turning process of the turning mechanism 10L, which is the left roller turning mechanism, and the right roller turning process of the turning mechanism 10R, which is the right roller turning mechanism.

[0112] As a result, the chassis dynamometer 1 of the first embodiment can restrain the lateral movement of the vehicle 60 even when the running test includes a tire turning movement.

[0113] (Anti-jump rollers) As shown in Figures 1 and 2, the chassis dynamometer 1 of embodiment 1 further includes four pairs of anti-jump rollers 4F and 4B that correspond to the four tires 6 and restrain the longitudinal movement of the vehicle 60.

[0114] The Y direction facing each other between the two tire pairs, the front tire pair and the rear tire pair, is defined as the longitudinal direction of the vehicle 60. The +Y direction from the rear tire pair toward the front tire pair is defined as the forward arrangement direction, and the −Y direction from the front tire pair toward the rear tire pair is defined as the rearward arrangement direction.

[0115] As described above, the four loading rollers each have a twin configuration consisting of the front roller 21F (22F) serving as a front loading roller and the rear roller 21B (22B) serving as a rear loading roller. The rear roller 21B serving as a rear loading roller is disposed on the rearward arrangement direction (-Y direction) side of the front roller 21F serving as a front loading roller.

[0116] As shown in Figure 9, the corresponding target tire (tire 6L shown in Figure 9) among the four tires 6 is placed from on the front roller 21F, which serves as the front placement roller, to on the rear roller 21B, which serves as the rear placement roller.

[0117] Each of the four pairs of anti-jump-out rollers 4F and 4B is composed of a front anti-jump-out roller 4F and a rear anti-jump-out roller 4B.

[0118] The forward jump-out prevention roller 4F is provided on the forward arrangement direction (+Y direction) side of the tire 6 that is the target tire to be placed, and rotates when it comes into contact with the target tire. The forward jump-out prevention roller 4F is disposed without making contact with the front roller 21F (22F).

[0119] The rear jump-out prevention roller 4B is provided on the rearward arrangement direction (-Y direction) side of the tire 6 that is the target tire to be placed, and rotates when it comes into contact with the target tire. The rear jump-out prevention roller 4B is disposed without coming into contact with the rear roller 21B (22B).

[0120] In this way, the pair of anti-fly-out rollers 4F and 4B provided corresponding to the tire to be placed, and the front roller 21F (21B) and rear roller 21B (22B) are provided independently of each other.

[0121] 10 is an explanatory diagram showing a schematic diagram of the forward jump-out prevention roller 4F and its peripheral components. The XYZ Cartesian coordinate system is shown in the figure. As shown in the figure, a rotating shaft 41 is attached to both sides of the forward jump-out prevention roller 4F, and both ends of the rotating shaft 41 are rotatably supported by bearings 42. The rotating shaft 41 is connected to the forward jump-out prevention roller 4F along the rotation center line CL4 of the forward jump-out prevention roller 4F.

[0122] The rear jump-out prevention roller 4B has a rotating shaft 41 and a bearing 42 as peripheral members, similar to the front jump-out prevention roller 4F, except that it is disposed in a rearward direction relative to the tire to be placed.

[0123] (Effect (3)) In the chassis dynamometer 1 of embodiment 1, the movement of the tire to be placed in the forward and rearward positions is restricted by four pairs of anti-jump rollers 4F and 4B, each of which includes a forward anti-jump roller 4F and a rear anti-jump roller 4B.

[0124] Therefore, the chassis dynamometer 1 of the first embodiment can accurately restrain the longitudinal movement of the vehicle 60 by using the four pairs of anti-jump-out rollers 4F and 4B.

[0125] In addition, since the pairs of anti-jump rollers 4F and 4B each rotate in conjunction with the rotation of the tire 6, wear on the tire 6 can be minimized when the vehicle 60 is restrained by the four pairs of anti-jump rollers 4F and 4B.

[0126] The above effects will be described in detail below. Because the jump-out prevention rollers 4 (4F, 4B) can rotate freely, the rotation speed of the jump-out prevention rollers 4 follows the rotation speed of the tire 6 that is in contact with the jump-out prevention rollers 4, and no speed difference occurs between the rotation speed of the tire 6 and the jump-out prevention rollers 4. Therefore, wear on the tire 6 can be kept to a minimum.

[0127] In addition, in the chassis dynamometer 1 of embodiment 1, the four pairs of anti-jump-out rollers 4F and 4B directly restrain only the four tires 6 (6L, 6R) of the vehicle 60, so that the longitudinal movement of the vehicle 60 can be restrained without any problems even if the vehicle model of the vehicle 60 is changed.

[0128] The wheelbase, which is the distance from the ground contact point of the front tire of the vehicle 60 to the ground contact point of the rear tire, changes when the vehicle model is changed. However, after changing the vehicle model of the vehicle 60, by moving the roller base (the swivel base 11 or the fixed base 15) in the longitudinal direction (Y direction) to fit the changed wheelbase, the positional relationship between the Y coordinate of the tire center point C6 of the tire 6 (6L and 6R) and the Y coordinate of the inter-roller center point can be matched to the state before the vehicle model change. Note that the "inter-roller center point" refers to the center position of the longitudinal (Y direction) distance between the front roller 21F (22F) and the rear roller 21B (22B) of each of the front wheel roller pair 21 and the rear wheel roller pair 22, and corresponds to the inter-roller center point C0 described below with reference to Figures 11 and 12. Furthermore, the longitudinal movement of the roller base can be performed using existing technology, just like the lateral movement.

[0129] In this way, even if the vehicle model of the vehicle 60 is changed, the positional relationship in the vertical direction between the tire center point C6 of the tire 6 and the inter-roller center point can always be set to be the same. Therefore, before and after the vehicle model of the vehicle 60 is changed, the side roller pairs 3L and 3R can be permanently arranged relatively easily so that each restraining roller 33 contacts the tire 6 (6L and 6R) at the contact point.

[0130] In addition, since the four pairs of anti-jump-out rollers 4F and 4B in the chassis dynamometer 1 of embodiment 1 are installed below the body of the vehicle 60 and near the tires 6, false detections by various sensors including the autonomous driving sensor of the vehicle 60 can be avoided, making it possible to respond to autonomous driving tests.

[0131] If the pairs of jump-out prevention rollers 4F and 4B were permanently fixed, it could be difficult to place the four tires 6 of the vehicle 60 on the four loading rollers. Therefore, it is desirable to arrange the four pairs of jump-out prevention rollers 4F and 4B as shown in Figures 1 and 2 after the vehicle 60 has been loaded. For this reason, for example, a movable arrangement can be considered in which the four pairs of jump-out prevention rollers 4F and 4B are provided with a lifting function, and are stored below the floor surface 50 before the vehicle 60 is loaded, and are moved above the floor surface 50 after the vehicle 60 has been loaded, and are arranged as shown in Figures 1 and 2.

[0132] In the above-described first embodiment, the pair of rollers 21 for the front wheels and the pair of rollers 22 for the rear wheels having a twin roller configuration are shown as the "four mounting rollers" on which the four tires 6 of the vehicle 60 are mounted, but it is theoretically possible to use a single roller having a single roller configuration instead of the twin roller configuration.

[0133] Second Embodiment A second embodiment of the present disclosure is a roller design method for a chassis dynamometer. A chassis dynamometer to be designed in the roller design method of the second embodiment (hereinafter abbreviated as "chassis dynamometer to be designed") will be described.

[0134] The chassis dynamometer to be designed may have a configuration in which the four pairs of anti-jump rollers 4F and 4B are omitted from the chassis dynamometer 1 of embodiment 1. Below, the essential components of the chassis dynamometer to be designed will be described with reference to the chassis dynamometer 1 of embodiment 1 shown in Figures 1 to 10.

[0135] The chassis dynamometer to be designed is equipped with four mounting rollers on which the four tires 6 of the vehicle 60 are mounted. The four tires 6 include two sets of tire pairs, and the two sets of tire pairs include a front tire pair and a rear tire pair.

[0136] The opposing direction between the two tire pairs is defined as the longitudinal direction (Y direction) of the vehicle 60, the direction from the rear tire pair to the front tire pair is defined as the forward arrangement direction (+Y direction), and the direction from the front tire pair to the rear tire pair is defined as the rear arrangement direction (-Y direction).

[0137] The four loading rollers each include a front roller 21F (22F) which serves as a front loading roller and a rear roller 21B (22B) which serves as a rear loading roller, and the rear roller 21B (22B) is arranged on the rearward arrangement side of the front roller 21F (22F), and the corresponding target tire among the four tires 6 is placed from on the front roller 21F to on the front roller 22F.

[0138] Fig. 11 is an explanatory diagram that schematically shows a dynamic model of the conditions for preventing the tire 6 placed on the front roller 21F and the rear roller 21B from jumping out. Fig. 12 is an explanatory diagram that shows the points related to the installation surface angle θ in Fig. 11. XYZ Cartesian coordinate systems are shown in Fig. 11 and Fig. 12. Fig. 11 shows the dynamic model when a vehicle 60 traveling in a vehicle traveling direction D50 stops.

[0139] The state of the tire 6 placed on the front roller 22F and rear roller 22B of the rear wheel roller pair 22 provided corresponding to the rear wheel tire pair is also the same as the state shown in Fig. 11. Hereinafter, the tire 6 (target tire) placed on the front roller 21F and rear roller 21B will be described as a representative with reference to Figs. 11 and 12.

[0140] 11 , the front roller 21F and the rear roller 21B have a common roller radius r, and are disposed at the same height and separated by a center-to-center distance L. The center-to-center distance L is the distance between the rotation center point C21F of the rear roller 21B and the rotation center point C21B of the rear roller 21B. The center point of the roller distance L is the inter-roller center point C0.

[0141] The roller design method of the second embodiment for the chassis dynamometer to be designed having the above-described configuration targets the front roller 21F (22F) and rear roller 21B (22B) of each of the four mounting rollers.

[0142] The roller design method of the second embodiment executes the following steps (a) and (b).

[0143] Step (a) is a step of setting a common roller radius r for the front roller 21F and the rear roller 21B.

[0144] Step (b) is a step for setting the distance L between the rollers.

[0145] The above steps (a) and (b) are characterized in that they are performed so that the roller radius r and the roller distance L satisfy the conditions for preventing jumping out.

[0146] The anti-jump condition is a condition under which, when a running test of a vehicle 60 is conducted with the target tire evenly placed on the front roller 21F and the rear roller 21B, the target tire does not deviate from the rear roller 21B or the front roller 21F when the vehicle 60 stops running or starts moving.

[0147] Note that "when the vehicle 60 stops running" refers to the timing when the vehicle 60 changes from a running state to a stopped state, and "when starting" refers to the timing when the vehicle 60 changes from a stopped state to a running state. The running test of the vehicle 60 includes the timing when the vehicle 60 stops running, when the vehicle 60 changes from a running state to a stopped state, and the timing when the vehicle 60 starts moving, when the vehicle 60 changes from a stopped state to a running state.

[0148] When the vehicle stops traveling, brakes are applied to the tires 6, which stops the rotation of the tires 6, but torque continues to be applied to the front roller 21F (22F) and rear roller 21B (22B), which are the loading rollers, to simulate inertia and maintain the rotation of the tires 6. The torque applied to the front roller 21F is the existing motor for driving the rotation of the front roller 21F, and the torque applied to the rear roller 21B is the existing motor for driving the rotation of the rear roller 21B.

[0149] Therefore, when the vehicle 60 stops, a force that throws it backward is generated in the vehicle 60. The conditions for preventing the vehicle 60 from jumping out when the vehicle 60 stops will be described in detail below. The conditions for preventing the vehicle 60 from jumping out are that the following formula (1) be satisfied.

[0150]

[0151] In equation (1), "R" is the tire radius R of the tire 6, and "F (= f)" is the tangential force generated when the vehicle stops moving. "m" is the weight of the vehicle 60 acting on one tire 6 (the tire to be placed), and "g" is the gravitational acceleration. Furthermore, "e" is the vertical distance in the Z direction, which is the direction of gravity, of the contact point CP between the tire 6 and the rear roller 21B.

[0152] The tangential force F in equation (1) can be derived from the following equation (2).

[0153]

[0154] In equation (2), the upper equation {μmg cosθ} and the lower equation {T / r+M Ｄ α}, the smaller value of the two equations is the tangential force F (= f). Note that "μ" is the coefficient of static friction between the tire and roller, "θ" is the installation surface angle, "T" is the dynamo torque, and "M Ｄ " is the amount of inertia of the roller, and "a" is the amount of acceleration / deceleration of the rear roller 21B.

[0155] The dynamo torque T is a drive torque applied to the rotational drive motor of the rear roller 21B when the rear roller 21B is rotated. The installation surface angle θ is the angle formed between the radial direction from the tire center point C6 of the tire 6 toward the contact point CP and the direction of gravity (-Z direction).

[0156] In equation (2), when the value of the lower equation of equation (2) exceeds the value of the upper equation, that is, {μmg·cos θ}<{T / r+M Ｄ · α} holds, the tire 6 will slip. Therefore, the maximum value of the tangential force F is determined by {μmg · cos θ} in the above formula. Therefore, the maximum value of the tangential force F can be kept low by keeping the value of the above formula in formula (2) low.

[0157] By adjusting the installation surface angle θ, which is one of the factors that determine the friction force in the above equation from equation (2), the value in the above equation can be reduced and the pop-out prevention condition can be satisfied. The installation surface angle θ can be derived from the following equation (3).

[0158]

[0159] From equation (3), the tire radius R and the roller distance L can be set so that the installation surface angle θ is closest to 90°.

[0160] Therefore, the roller design method of the embodiment is characterized in that the roller radius r and the inter-roller distance L are set so as to satisfy the pop-out prevention condition (equation (1)) when steps (a) and (b) are performed.

[0161] Since it is relatively difficult to change the roller radius r, by taking into account the roller radius r and tire radius R in equation (3) and setting the inter-roller distance L relatively long so as to satisfy the anti-jumping condition, it is possible to prevent the vehicle 60 from jumping out due to vertical movement of the vehicle 60 when it is stopped.

[0162] Hereinafter, the method of setting the roller distance L relatively long may be referred to as the "center distance enlargement method."

[0163] When the vehicle 60 starts moving and changes from a stopped state to a running state, the same jump-out prevention condition exists as a condition for preventing the tire to be placed from deviating from the front roller 21F (22F) as when the vehicle 60 is stopped. In this case, the only difference is that the condition target is replaced from the front roller 21F to the rear roller 21B (22B), so it is sufficient to execute steps (a) and (b) described above as the roller design method.

[0164] (Effect) As described above, the roller design method for a chassis dynamometer, which is the second embodiment of the present disclosure, designs the front roller 21F and rear roller 21B of each of the four mounting rollers, and performs steps (a) and (b) so that the roller radius r and the center-to-center distance L between the rollers satisfy the conditions for preventing jumping out.

[0165] Therefore, the chassis dynamometer having four mounting rollers designed using the roller design method of embodiment 2 has the effect of preventing the tire from popping out, in which the target tire deviates from the rear mounting roller, rear roller 21B (22B), when the vehicle 60 stops moving.

[0166] In this way, a chassis dynamometer having four loading rollers designed using the roller design method of embodiment 2 satisfies the anti-jump conditions, and therefore the four pairs of anti-jump rollers 4F and 4B provided in the chassis dynamometer 1 of embodiment 1 are unnecessary.

[0167] On the other hand, there may be cases where the center distance expansion method in the roller design method cannot satisfy the jump-out prevention conditions due to restrictions on the installation of the loading rollers, etc. In such cases, it is desirable to provide four pairs of jump-out prevention rollers 4F and 4B, as in the chassis dynamometer 1 of embodiment 1.

[0168] Conversely, if it is difficult to provide a pair of anti-jump rollers 4F and 4B, as in the chassis dynamometer 1 of embodiment 1, due to interference between the anti-jump roller pairs 4F and 4B and various mechanical equipment related to the chassis dynamometer, the roller design method of embodiment 2 is effective.

[0169] Similarly, when the vehicle 60 starts moving and changes from a stopped state to a running state, there is a jump-out prevention condition (a conditional expression equivalent to the contents shown in formulas (1) to (3)) that prevents the tire to be placed from deviating from the forward jump-out prevention roller 4F. In this case, the difference is that the condition target is replaced from the rear jump-out prevention roller 4B to the forward jump-out prevention roller 4F.

[0170] Therefore, the chassis dynamometer having four mounting rollers designed using the roller design method of embodiment 2 has the effect of preventing the tire from jumping out of the front mounting roller 21F (21B) when the vehicle 60 starts moving.

[0171] In this way, the chassis dynamometer having four mounting rollers designed using the roller design method of embodiment 2 has the effect of preventing the tire to be mounted from jumping out of the front roller 21F (21B) or the rear roller 21B (22B) during a running test.

[0172] (Jump-out Prevention Conditions of the Chassis Dynamometer 1 of the First Embodiment) Hereinafter, the jump-out prevention conditions of the chassis dynamometer 1 provided with the jump-out prevention roller pairs 4F and 4B will be described.

[0173] 13 is an explanatory diagram showing a schematic diagram of a dynamic model of the conditions for preventing the tire 6 from jumping out when the pairs of anti-jump rollers 4F and 4B are provided. The figure shows an XYZ orthogonal coordinate system. The figure shows the state in which the pairs of anti-jump rollers 4F and 4B are in contact with the tire 6.

[0174] When the pair of jump-out prevention rollers 4F and 4B is provided, the condition is met in which the tire to be placed does not deviate from the rear jump-out prevention roller 4B or the front jump-out prevention roller 4F when the vehicle 60 stops or starts moving.

[0175] Therefore, the roller radius r in equation (3) is the roller radius r4 common to the pair of jump-out prevention rollers 4F and 4B, and the inter-roller distance L in equation (3) is the inter-roller distance L4 from the rotation center point C4F of the front jump-out prevention roller 4F to the rotation center point C4B of the rear jump-out prevention roller 4B. In other words, when the pair of jump-out prevention rollers 4F and 4B are provided, equation (3) is transformed into the following equation (4):

[0176]

[0177] Therefore, the contact surface angle θ shown in equations (2) and (4) is the angle formed between the direction of gravity (-Z direction) and the radial direction from the tire center point C6 of the tire 6 toward the contact point CP4. The contact point CP4 is the point of contact between the tire 6 and the rearward jump-out prevention roller 4B.

[0178] In this way, by providing the pair of anti-jump-out rollers 4F and 4B, it is possible to set the roller radius r4 and the inter-roller distance L4 relatively easily so that the installation surface angle θ is close to 90°.

[0179] Therefore, the chassis dynamometer 1 of the first embodiment has four pairs of anti-jump-out rollers 4F and 4B, and therefore can easily and reliably satisfy the anti-jump-out conditions.

[0180] <Others> Although the present disclosure has been described in detail, the above description is merely illustrative in all respects and does not limit the present disclosure. It is understood that countless variations not illustrated can be envisioned without departing from the scope of the present disclosure.

[0181] 3, 3L, 3R Side rollers 4, 4B, 4F Anti-jump rollers 6, 6L, 6R Tires 10, 10L, 10R Swivel mechanism 11, 11L, 11R Swivel base 15 Fixed base 21 Front wheel roller pair 21B, 22B Rear rollers 21F, 22F Front rollers 22 Rear wheel roller pair 31 Inner side roller 32 Outer side roller 33 Restraining roller 34 Bearing 35 Fixed shaft 36 Pressing cylinder 37 Shaft mounting member 60 Vehicle

Claims

1. A chassis dynamometer comprising: four mounting rollers for mounting four tires of a vehicle; and four side rollers provided corresponding to the four tires and restraining the lateral movement of the vehicle; the four tires include two sets of tire pairs, the two sets of tire pairs including a front tire pair and a rear tire pair, the two sets of tire pairs including a left tire and a right tire disposed on the left and right, respectively; the direction in which the left tire and the right tire face each other is defined as the lateral direction of the vehicle, and the outer or inner side of each of the left tire and the right tire is defined as the contact side; the four side rollers include two sets of side roller pairs corresponding to the two sets of tire pairs; each of the two sets of side roller pairs includes a left side roller that contacts the left tire on the contact side and applies a left tire restraining force to the left tire along the left tire restraining direction, and a right side roller that contacts the contact side of the right tire and applies a right tire restraining force to the right tire along the right tire restraining direction; a left tire restraining direction being a direction from the left side roller toward the left tire, and a right tire restraining direction being a direction from the right side roller toward the right tire.

2. A chassis dynamometer as defined in claim 1, wherein the left side roller and the right side roller each include a fixed shaft, a bearing mounted on the fixed shaft so as to be rotatable around the fixed shaft as a rotation axis, and a restraining roller that has the bearing inside and rotates integrally with the bearing, the restraining roller contacting the lower region of the tire on the contact side of the tire and rotating in conjunction with the rotation of the tire.

3. A chassis dynamometer as set forth in claim 2, wherein the four mounting rollers include a left-side rotating target roller and a right-side rotating target roller on which one of the front tire pair and the rear tire pair is mounted, and the chassis dynamometer further comprises a left-side roller rotating mechanism that performs a left-side roller rotating process to turn the left-side rotating target roller, and a right-side roller rotating mechanism that performs a right-side roller rotating process to turn the right-side rotating target roller, the left-side roller rotating mechanism including a left-side rotating table that turns when the left-side roller rotating process is performed, and the right-side roller rotating mechanism including a right-side rotating table that turns when the right-side roller rotating process is performed, one of the left-side side rollers of each of the two sets of side roller pairs includes a left-side rotating target side roller that turns together with the left-side rotating table, and one of the right-side side rollers of each of the two sets of side roller pairs includes a right-side rotating target side roller that turns together with the right-side rotating table, and the left-side rotating target side roller is a left shaft mounting member that holds the fixed shaft movably along the left tire restraining direction, and a left pressure cylinder that is provided on the left swivel base and that applies a left tire pressing force along the left tire restraining direction to the left shaft mounting member; wherein the right side roller to be turned further includes a right shaft mounting member that holds the fixed shaft movably along the right tire restraining direction, and a right pressure cylinder that is provided on the right swivel base and that applies a right tire pressing force along the right tire restraining direction to the right shaft mounting member, wherein the left tire restraining force includes the left tire pressing force, and the right tire restraining force includes the right tire pressing force.

4. A chassis dynamometer according to any one of claims 1 to 3, wherein the contact side is the inside of the tire, the restraining direction of the left tire is to the left, and the restraining direction of the right tire is to the right.

5. A chassis dynamometer according to any one of claims 1 to 3, wherein the contact side is the outside of the tire, the restraining direction of the left tire is to the right, and the restraining direction of the right tire is to the left.

6. A chassis dynamometer as set forth in any one of claims 1 to 5, further comprising four pairs of anti-jump-out rollers provided corresponding to the four tires and restraining the longitudinal movement of the vehicle, wherein the opposing direction between the two pairs of tires is defined as the longitudinal direction of the vehicle, the direction from the rear tire pair toward the front tire pair is defined as the forward placement direction, and the direction from the front tire pair toward the rear tire pair is defined as the rear placement direction, wherein the four loading rollers each include a front loading roller and a rear loading roller, the rear loading rollers are disposed on the rear placement direction side of the front loading rollers, and a corresponding target tire of the four tires is loaded from above the front loading roller onto the rear loading roller, wherein the four pairs of anti-jump-out rollers are each provided on the forward placement direction side of the target tire, and a front anti-jump-out roller that rotates when in contact with the target tire, a rearward jump-out prevention roller that is provided on the rearward placement direction side of the tire to be placed and that rotates when it comes into contact with the tire to be placed.

7. A roller design method for a chassis dynamometer, wherein the chassis dynamometer is equipped with four mounting rollers for mounting four tires of a vehicle, the four tires including two sets of tire pairs, the two sets of tire pairs including a front tire pair and a rear tire pair, the opposing direction between the two sets of tire pairs is defined as the longitudinal direction of the vehicle, the direction from the rear tire pair toward the front tire pair is defined as the forward placement direction, and the direction from the front tire pair toward the rear tire pair is defined as the rear placement direction, the four mounting rollers each include a front mounting roller and a rear mounting roller, the rear mounting roller is positioned on the rear placement direction side of the front mounting roller, and a corresponding target tire of the four tires is mounted from on the front mounting roller to on the rear mounting roller, a step of setting the center distance between the front and rear mounting rollers, wherein the front mounting rollers and the rear mounting rollers have a common roller radius, and are arranged at the same height and separated by a center distance, the center distance being the distance between the center point of rotation of the front mounting roller and the center point of rotation of the rear mounting roller; the roller design method is characterized in that each of the four mounting rollers is a design object, and comprises: (a) a step of setting the roller radius; and (b) a step of setting the center distance, and the steps (a) and (b) are performed so that the roller radius and the center distance satisfy a jump-out prevention condition, and the jump-out prevention condition is a condition under which, when the target tire is placed on the front mounting rollers and the rear mounting rollers and a running test of the vehicle is conducted, the target tire does not deviate from the front mounting rollers or the rear mounting rollers when the vehicle stops running and when the vehicle starts moving.

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