Dynamometer unit

Abstract

To provide a dynamometer unit 1 capable of turning a dynamometer 2 with reproduction of steering torque of a steering wheel during actual traveling when a traveling performance of a vehicle is evaluated in a simulation.SOLUTION: A dynamometer unit 1 includes: a dynamometer 2 attached to a drive wheel connection part of a vehicle in place of the driving wheels of a vehicle and housed in a tire house, the dynamometer 2 incorporating a load motor for applying torque to the drive wheel connection part of the vehicle; a turning part 31 to which the dynamometer 2 is connected; and a stand 3 at least turnably supporting the dynamometer 2. The stand 3 includes a steering torque reproduction mechanism that adjusts resistance to turning motion when the turning part 31 turns together with the dynamometer 2 by steering of the steering wheel of the vehicle and reproduces a steering torque of the steering wheel dependent on vehicle speed.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a dynamometer unit provided in a chassis dynamometer device for simulating and evaluating the driving performance of an automobile.

Background Art

[0002] Conventionally, as this type of dynamometer unit, the drive wheels of an automobile are removed, and the output shaft of a power source such as a load motor that applies torque to the wheel shaft is connected to the wheel shaft of the automobile, and a force applying means for applying a force that changes the steering angle of a drive wheel connecting portion such as a wheel hub is provided (see, for example, Patent Document 1). The dynamometer unit described in Patent Document 1 incorporates a power source, and the dynamometer unit includes a mount that enables the movement of the power source according to the change in the steering angle of the drive wheel connecting portion.

[0003] However, since the dynamometer unit described in Patent Document 1 is disposed outside the tire house of the automobile, when simulating and evaluating the driving performance of the automobile, the steering torque of the steering wheel required to change the steering angle of the drive wheel connection portion becomes larger than that during actual driving. Therefore, in the dynamometer unit described in Patent Document 1, a force is applied by the above-described force applying means so that the steering torque of the steering wheel becomes equal to that during actual driving.

[0004] On the other hand, the applicant of the present application has developed a dynamometer that is replaced with the drive wheels of an automobile, attached to the drive wheel connection portion of the automobile, and housed in the tire house, and incorporates a load motor that applies torque to the drive wheel connection portion of the automobile, and a mount that is connected to the dynamometer and supports the dynamometer at least rotatably. The load motor is housed in a case having a peripheral wall portion and an end wall portion that covers one end surface of the peripheral wall portion (see, for example, Patent Documents 2 and 3).

[0005] In the dynamometer units described in Patent Documents 2 and 3, the force applying means provided in the dynamometer unit described in Cited Document 1 is unnecessary, and the steering angle of the drive wheel connection portion can be freely changed only by the steering torque of the steering wheel, and the dynamometer turns in the steering direction.

[0006] On the other hand, regarding the dynamometer units described in Patent Documents 2 and 3, a new problem has been found that the steering torque of the steering wheel required for the turning of the dynamometer is smaller than that during actual running, and it is difficult to become an appropriate value according to the vehicle speed of the automobile.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0008] In view of the above points, an object of the present invention is to provide a dynamometer unit capable of reproducing the steering torque of the steering wheel during actual running and turning the dynamometer when simulating and evaluating the running performance of an automobile.

Means for Solving the Problems

[0009] In order to solve the above problems, the present invention provides a dynamometer unit provided in a chassis dynamometer device for simulating and evaluating the running performance of an automobile. The dynamometer unit is replaced with a driving wheel of the automobile and attached to a driving wheel connection part of the automobile, and is housed in a tire house. The dynamometer incorporates a load motor for applying torque to the driving wheel connection part of the automobile. The dynamometer unit includes a dynamometer and a pedestal to which the dynamometer is connected and which supports the dynamometer at least rotatably. In the dynamometer, the load motor is housed in a case having a peripheral wall portion and an end wall portion covering one end surface of the peripheral wall portion. The pedestal has a swivel portion whose swivel axis is vertically provided downward from the central portion of the bottom surface and to which the case of the dynamometer is connected, and a slide portion that pivotally supports the swivel axis of the swivel portion and is slidable in both the vehicle width direction and the vehicle length direction on the installation surface of the dynamometer unit. In a state where the case of the dynamometer is connected to the swivel portion and the swivel portion is rotatable with respect to the slide portion, the pedestal is provided with a steering torque reproduction mechanism that adjusts the resistance to the swivel movement when the swivel portion rotates together with the dynamometer by steering the steering wheel of the automobile and reproduces the steering torque of the steering wheel according to the vehicle speed of the automobile.

[0010] According to the present invention, when simulating and evaluating the running performance of an automobile, it is possible to adjust and apply the resistance to an appropriate magnitude with respect to the swivel movement when the swivel portion is rotated together with the dynamometer by steering the steering wheel of the automobile. Therefore, it is possible to reproduce the steering torque of the steering wheel during actual running.

[0011] In the present invention, it is desirable that the steering torque reproduction mechanism includes a pressurized air supply adjustment means for supplying pressurized air between the bottom surface of the swivel part of the mount and the upper surface of the slide part, and adjusting at least one of the pressure and flow rate of the pressurized air to adjust the resistance. According to this, the swivel part of the mount to which the dynamometer is connected can be lifted from the slide part of the mount by the pressurized air supplied from the pressurized air supply adjustment means. The amount of lift of the swivel part can be changed by adjusting at least one of the pressure and flow rate of the pressurized air, and the resistance to the swivel motion when the swivel part is swiveled together with the dynamometer by steering the steering wheel of the automobile can be adjusted by the amount of lift of the swivel part.

[0012] Also, in the present invention, in the mount, it is desirable that the upper surface of the slide part is sized such that the bottom surface of the swivel part does not protrude even during swiveling. According to this, the amount of lift of the swivel part of the mount to which the dynamometer is connected from the slide part of the mount is kept constant regardless of the swivel angle of the swivel part under the same resistance. For this reason, the resistance to the swivel motion when the swivel part is swiveled together with the dynamometer by steering the steering wheel of the automobile does not change depending on the swivel angle of the swivel part and is kept constant.

[0013] Furthermore, in the present invention, it is desirable that the steering torque reproduction mechanism includes a brake disk arranged parallel to the slide part and fixed to the swivel axis of the swivel part, and a brake caliper incorporating a pair of brake pads that sandwich the brake disk from above and below, and adjusting the braking force of the brake disk by the brake pads to adjust the resistance. According to this, the braking force of the brake disk by the brake pads can be adjusted, and the resistance to the swivel motion when the swivel part is swiveled together with the dynamometer by steering the steering wheel of the automobile can be adjusted.

[0014] In the present invention, it is desirable that a plate having a friction coefficient on its upper surface set to the minimum value during the running of the automobile is interposed between the bottom surface of the turning portion of the gantry and the upper surface of the slide portion in the steering torque reproduction mechanism. According to this, when simulating and evaluating the running performance of the automobile, it is possible to reproduce the resistance to the turning motion during the high-speed running of the automobile.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0016] (First Embodiment) Referring to FIGS. 1(a), 1(b), and 1(c), the dynamometer unit 1 of the first embodiment includes a dynamometer 2 and a pedestal 3. Similar to the dynamometer unit previously developed by the applicant of this application, the dynamometer 2 is replaced with a driving wheel of an automobile (not shown) and attached to a driving wheel connection part such as a wheel hub of the automobile, and a load motor for applying torque to the driving wheel connection part is incorporated therein. This load motor is housed inside a case 21 that constitutes the outer shell of the dynamometer 2, and together with the case 21, it is housed inside the tire house of the automobile. The case 21 has a cylindrical peripheral wall portion 211 and a disk-shaped end wall portion 212 that covers one end face of the peripheral wall portion 211, specifically, the end face located on the outer side in the vehicle width direction of the automobile, and is hollow. The load motor is housed inside such a hollow case 21. The load motor is pivotally supported by a bearing provided at the center of the end wall portion 212 of the case 21, extends in a direction orthogonal to the end wall portion 212 inside the case 21, and includes a rotor shaft that is connected to the driving wheel connection part of the automobile. Further, the stator of the load motor is provided on the inner peripheral portion of the peripheral wall portion 211 of the case 21. And one end of the load motor is fixed to a portion of the rotor shaft located on the end wall portion 212 side, extends radially toward the stator in the end wall portion 212, and the other end is provided with a rotor frame having a magnet or the like fixed thereto with a predetermined gap between it and the stator. With such a rotor frame and the hollow case 21, the load motor, together with the case 21, fits inside the tire house of the automobile without interfering with the driving wheel connection part of the automobile.

[0017] A dynamometer 2 is connected to a mount 3, and the mount 3 supports the dynamometer 2 at least rotatably. The mount 3 includes a swivel part 31 and a slide part 32 that is separate from the swivel part 31. The outer shell of the swivel part 31 of the mount 3 is formed by a bottom wall 311 and an outer peripheral wall 312 that rises upward from the outer periphery of the bottom wall 311, and is open upward. The dynamometer 2 is connected to the swivel part 31 of the mount 3. Specifically, at the lower end of the case 21 of the dynamometer 2, a pair of legs 213 extending downward are provided on the radially outer side of the case 21, and each leg 213 has a flange at its lower end. Inside the swivel part 31 of the mount 3, a pair of leg receivers rising upward are provided at positions facing the lower ends of the respective legs 213 (not shown in the figure), and each leg receiver has a flange on its upper end on which the flange of each leg 213 is placed. Then, by overlapping the flanges of the respective legs 213 on the flanges of the respective leg receivers and fastening both flanges using bolts, the dynamometer 2 is connected to the swivel part 31 of the mount 3.

[0018] As shown in FIG. 1(b), a swivel shaft 313 is vertically provided downward from the central part of the bottom surface of the bottom wall 311 in the swivel part 31 of the mount 3, and the swivel shaft 313 is located at the central part in both the vehicle length direction and the vehicle width direction when the swivel part 31 is not swiveling. The slide part 32 of the mount 3 is installed on the installation surface of the dynamometer unit 1 in the same manner as the dynamometer unit previously developed by the present applicant, and is slidable in both the vehicle width direction and the vehicle length direction. Specifically, the slide part 32 includes a movable table 321 on which the swivel part 31 can be horizontally placed, and a pair of slide tables 322, 322 that support the movable table 321 slidably in both the vehicle length direction and the vehicle width direction at the lower sides of both ends in the vehicle length direction thereof. Further, the slide part 32 also includes a swivel bearing 323 vertically provided downward at the central part of the movable table 321 in both the vehicle length direction and the vehicle width direction. By fitting the swivel shaft 313 of the swivel part 31 into the swivel bearing 323 of the slide part 32 and pivotally supporting it with the swivel bearing 323, the mount 3 enables the swivel part 31 to be rotatable relative to the slide part 32 with the case 21 of the dynamometer 2 connected to the swivel part 31.

[0019] Although not shown in the figure, each slide table 322 of the slide section 32 is composed of a first slide table that realizes slides on both sides in the vehicle length direction and a second slide table that realizes slides on both sides in the vehicle width direction, and the second slide table is provided on the first slide table. The first slide table includes a first base that is fixed immovably with respect to the installation surface of the dynamometer unit 1 and is horizontally arranged, and a plurality of first rails that are fixed on the upper surface of the first base at a predetermined interval in the vehicle width direction and are longitudinal in the vehicle length direction. Each first rail is provided with a first slider that is slidable in the longitudinal direction of each first rail. The second slide table is placed on all the first sliders of the first table and includes a second base that is horizontally arranged, and a plurality of second rails that are fixed on the upper surface of the second base at a predetermined interval in the vehicle length direction and are longitudinal in the vehicle width direction. Each second rail is provided with a second slider that is slidable in the longitudinal direction of each second rail. Further, the first slide table has a first return means that uses air pressure, hydraulic pressure, etc. to return to the neutral position after sliding in the vehicle length direction with the non-sliding state as the neutral position. Similarly, the second slide table has a second return means that uses air pressure, hydraulic pressure, etc. to return to the neutral position after sliding in the vehicle width direction with the non-sliding state as the neutral position. The movable table 321 of the slide section 32 is horizontally arranged on the second sliders provided on the second slide table of each slide table 322. Therefore, the movable table 321 is slidable in both the vehicle length direction and the vehicle width direction. For this reason, when the swing shaft 313 of the swing section 31 to which the dynamometer 2 is connected is pivotally supported by the pivot bearing 323 of the slide section 32, the slide section 32 enables the swing section 31 to slide together with the dynamometer 2 freely.

[0020] Then, on the mount 3, there is provided a steering torque reproduction mechanism that adjusts the resistance to the turning motion when the turning part 31 turns together with the dynamometer 2 by the steering of the steering wheel of the automobile, and reproduces the steering torque of the steering wheel according to the vehicle speed of the automobile. As this steering torque reproduction mechanism, in the dynamometer unit 1 of the first embodiment, an air bearing is adopted. This air bearing has, as basic components, air bearing pads 4 provided on the bottom surface of the bottom wall 311 of the turning part 31 except for the turning shaft 313, and arranged on one side and the other side in the vehicle length direction during non-turning, and the upper surface of the movable base 321 of the slide part 32.

[0021] Referring to FIG. 2, the two air bearing pads 4, 4 jet pressurized air from their bottom surfaces toward the upper surface of the movable base 321 of the slide part 32 to lift the turning part 31 together with the dynamometer 2 from the upper surface of the movable base 321 of the slide part 32. Such an air bearing further has pressurized air supply adjustment means 5 that makes the lifting amounts from the movable base 321 of the turning part 31 the same for both air bearing pads 4, 4 and adjusts at least one of the pressure and flow rate of the pressurized air to be jetted. The pressurized air supply adjustment means 5 is a supply source of pressurized air to each air bearing pad 4, and includes an air control unit 51 that adjusts at least one of the pressure and flow rate of the pressurized air, an air hose 52 that is a flow path of the pressurized air supplied by the air control unit 51, a manifold 53 that evenly distributes the pressurized air supplied through the air hose 52 to each air bearing pad 4, and air pipes 54 that are flow paths of the pressurized air distributed by the manifold 53 to each air bearing pad 4.

[0022] Note that, in the pressurized air supply adjustment means 5, the air control unit 51 is arranged at a position that does not interfere with the turning of the dynamometer 2 and the turning part 31 of the mount 3. Also, the manifold 53 is fixed to the outer peripheral wall 312 of the turning part 31 shown in FIGS. 1(a) and 1(b), but is arranged near the axis of the turning shaft 313 so as to have as little influence as possible on the torque required for the turning of the turning part 31. Further, the air pipes 54 are fixed to the bottom wall 311 of the turning part 31, like both air bearing pads 4, 4.

[0023] Referring to FIGS. 3(a), (b), and (c), a plurality of ejection holes 41 through which pressurized air ejects are formed in the lower surface of each air bearing pad 4. The ejection holes 41 are arranged such that the floating amount from the upper surface of the movable table 321 of the slide portion 32 of the swivel portion 31 of the gantry 3 to which the dynamometer 2 is connected, as shown in FIGS. 1(a) and (b), is uniform regardless of the positions in the vehicle length direction and the vehicle width direction. Such an arrangement of the ejection holes 41 is not limited to that shown in FIG. 3(a). Further, inside each air bearing pad 4, a plurality of pressurized air flow paths 42 communicating with the ejection holes 41 are formed according to the arrangement of the ejection holes 41. The pressurized air flow path 42 is formed by a main flow path 421 to which the air pipe 54 shown in FIG. 2 is connected and branch flow paths 422 branching from the main flow path 421. In each air bearing pad 4, for example, one main flow path 421 is formed at each of the central portions in both the vehicle width direction and the vehicle length direction of the swivel portion 31 when not in rotation. The branch flow paths 422 are formed in parallel with the main flow path 421 in the vehicle width direction of the swivel portion 31 when not in rotation at a predetermined interval in the vehicle length direction and are orthogonal to the main flow path 421 in the vehicle length direction of the swivel portion 31 when not in rotation. The air pipe 54 shown in FIG. 2 is connected to either one of the two main flow paths 421 in consideration of the fixing position of each air bearing pad 4 with respect to the bottom wall 311 of the swivel portion 31. Also, each main flow path 421 can be formed to penetrate each air bearing pad 4 from one end to the other end in the vehicle length direction or the vehicle width direction of the swivel portion 31 when not in rotation, or can be formed non-penetrating. In any case, the openings located at the end faces of each air bearing pad 4 of the main flow path 421 to which the air pipe 54 is not connected are plugged to prevent the pressurized air from leaking. On the other hand, each branch flow path 422 is basically formed non-penetrating, and the openings located at the end faces of each air bearing pad 4 in the vehicle length direction or the vehicle width direction of the swivel portion 31 when not in rotation are plugged. Further, nozzles 43 are provided between each ejection hole 41 and each main flow path 421 and each branch flow path 422 to suppress the pressure loss when the pressurized air flowing through each main flow path 421 and each branch flow path 422 ejects from each ejection hole 41.

[0024] When the above air bearings are adopted as the steering torque reproduction mechanism, as shown in FIG. 4, when making the pressure of the pressurized air supplied from the air control unit 51 shown in FIG. 2 to each air bearing pad 4 constant, the floating amount from the movable table 321 of the slide part 32 of the turning part 31 of the pedestal 3 to which the dynamometer 2 is connected increases as the flow rate of the pressurized air increases. Also, although not shown, when making the flow rate of the pressurized air constant, when increasing the pressure of the pressurized air, the above floating amount increases. Further, as shown in FIG. 5, when the above floating amount increases, the load capacity, that is, the apparent total weight of the dynamometer 2 and the turning part 31 of the pedestal 3 decreases. From these facts, in the dynamometer unit 1 of the first embodiment, when reducing the floating amount from the movable table 321 of the slide part 32 of the turning part 31 of the pedestal 3 to which the dynamometer 2 is connected, the steering torque of the steering wheel of the automobile required for the turning of the turning part 31 of the pedestal 3 to which the dynamometer 2 is connected can be increased.

[0025] Therefore, in the dynamometer unit 1 of the first embodiment, in a state corresponding to when the vehicle is stopped, pressurized air is not supplied from the air control unit 51 to each air bearing pad 4 so that the steering torque of the steering wheel of the vehicle becomes maximum, and the bottom surface of the bottom wall 311 of the turning part 31 and the upper surface of the movable table 321 of the slide part 32 are brought into contact with each other. However, the upper surface of the movable table 321 is adjusted in advance by surface treatment, spraying a solid lubricant, etc. so that its coefficient of friction becomes a magnitude corresponding to so-called setting at the time of actual running. Then, pressurized air is supplied from the air control unit 51 to each air bearing pad 4 while adjusting at least one of the pressure and flow rate of the pressurized air according to the vehicle speed of the vehicle, and the floating amount of the turning part 31 of the gantry 3 from the movable table 321 of the slide part 32 is adjusted. In this way, the resistance to the turning motion when the turning part 31 turns together with the dynamometer 2 by steering the steering wheel of the vehicle can be adjusted. Specifically, when the vehicle is running at a low speed, the floating amount of the turning part 31 from the movable table 321 of the gantry 3 is reduced, and when running at a high speed, the floating amount is increased. Therefore, when simulating and evaluating the running performance of the vehicle, the resistance to the turning motion when turning the turning part 31 together with the dynamometer 2 by steering the steering wheel of the vehicle can be adjusted to an appropriate magnitude and applied. For this reason, the steering torque of the steering wheel during actual running can be reproduced according to the vehicle speed of the vehicle.

[0026] In addition, in the dynamometer unit 1 of the second embodiment, as shown in Fig. 1(c), in the gantry 3, the upper surface of the slide part 32, that is, the upper surface of the movable table 321, is sized so that the bottom surface of the turning part 31 does not protrude even during turning. By doing so, the floating amount of the turning part 31 of the gantry 3 to which the dynamometer 2 is connected from the movable table 321 of the slide part 32 is kept constant regardless of the turning angle of the turning part 31 under the same resistance. For this reason, the resistance to the turning motion when turning the turning part 31 together with the dynamometer 2 by steering the steering wheel of the vehicle does not change depending on the turning angle of the turning part 31 and is kept constant.

[0027] (Second Embodiment) Referring to FIGS. 6(a) and 6(b), the dynamometer unit 1 of the second embodiment will be described below. In FIGS. 6(a) and 6(b), parts common to the dynamometer unit 1 of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0028] In the dynamometer unit 1 of the second embodiment, a disk brake is adopted as the steering torque reproduction mechanism. This disk brake includes a plate-shaped brake disk 324, which is arranged in parallel with the slide portion 32 and fixed to the turning axis 313 of the turning portion 31 of the gantry 3 and is circular, semicircular, crescent-shaped, etc. in plan view, and a brake caliper 325 that holds a pair of brake pads 325a, 325a for sandwiching the brake disk 324 from above and below. In the dynamometer unit 1 of the second embodiment, a through hole that penetrates the movable base 321 in the vertical direction is formed at the center of the movable base 321 of the slide portion 32 in the vehicle length direction and the vehicle width direction, and the turning axis 313 of the turning portion 31 is inserted into this through hole. Further, the brake disk 324 is housed between a pair of slide tables 322, 322. Therefore, the brake disk 324 rotates together with the turning axis 313 when the turning portion 31 of the gantry 3 turns.

[0029] Also, in the dynamometer unit 1 of the second embodiment, the brake caliper 325 is fixed to the movable table 321 of the slide portion 32. Therefore, when the brake caliper 325 slides in the vehicle length direction and the vehicle width direction of the movable table 321, it slides in the vehicle length direction and the vehicle width direction together with the movable table 321. Further, the portion of the brake caliper 325 provided with each brake pad 325a moves in the vertical direction, enabling adjustment of the braking pressure of the brake disc 324 by both brake pads 325a, 325a. The vertical movement of the portion of the brake caliper 325 provided with each brake pad 325a can be realized by an air pressure method, a hydraulic pressure method, or the like. Note that in the dynamometer unit 1 of the second embodiment, the brake calipers 325 are provided as a pair at positions facing each other in the radial direction of the brake disc 324, but the number of installed brake calipers 325 can be changed to one or three or more according to the required braking pressure.

[0030] When the above disk brake is adopted as the steering torque reproduction mechanism, as shown in FIG. 7, the brake torque of the disk brake, that is, the braking force, is proportional to the braking pressure of the brake disc 324 by the pair of brake pads 325a, 325a of the brake caliper 325. That is, in the dynamometer unit 1 of the second embodiment, when the braking pressure of the brake disc 324 by both brake pads 325a, 325a is increased, the steering torque of the steering wheel of the automobile required for the turning of the turning portion 31 of the gantry 3 to which the dynamometer 2 is connected can be increased.

[0031] Therefore, in the dynamometer unit 1 of the second embodiment, in a state corresponding to when the vehicle is stopped, the braking force is minimized by minimizing the brake pressure of the brake disk 324 by the two brake pads 325a, 325a so that the steering torque of the steering wheel of the vehicle is minimized, and the bottom surface of the bottom wall 311 of the turning section 31 is brought into contact with the upper surface of the movable base 321 of the slide section 32. In this case, as shown in FIGS. 6(a) and 6(b), a pair of flat plates 326, 326 having a friction coefficient set to the minimum value during the running of the vehicle are interposed between the bottom surface of the bottom wall 311 of the turning section 31 and the upper surface of the movable base 321. Each plate 326 is disposed on each of one side and the other side in the vehicle length direction excluding the through-hole of the movable base 321 of the slide section 32 when the turning section 31 is not turning so as not to hinder the turning of the turning section 31. Then, according to the vehicle speed of the vehicle, the brake pressure of the brake disk 324 by the pair of brake pads 325a, 325a is adjusted to adjust the braking force of the brake disk 324. In this way, the resistance to the turning motion when the turning section 31 turns together with the dynamometer 2 by steering the steering wheel of the vehicle can be adjusted. Specifically, when the vehicle is running at a low speed, the braking force of the brake disk 324 by the two brake pads 325a, 325a is increased, and when the vehicle is running at a high speed, the braking force is decreased. Therefore, when simulating and evaluating the running performance of the vehicle, the resistance to the turning motion when the turning section 31 is turned together with the dynamometer 2 by steering the steering wheel of the vehicle can be adjusted to an appropriate magnitude and applied. For this reason, the steering torque of the steering wheel during actual running can be reproduced according to the vehicle speed of the vehicle. For example, when simulating and evaluating the running performance of the vehicle, the resistance to the turning motion during high-speed running of the vehicle can be reproduced by making the braking force of the brake disk 324 by the two brake pads 325a, 325a substantially zero.

[0032] Note that in the dynamometer unit 1 of the second embodiment, as shown in FIG. 6(b), unlike the dynamometer unit 1 of the first embodiment, in the gantry 3, it is not always necessary to make the upper surface of the slide portion 32, that is, the upper surface of the movable table 321, large enough so that the bottom surface of the turning portion 31 does not protrude even during turning.

[0033] As described above, the embodiments of the present invention have been described with reference to the drawings, but the present invention is not limited thereto. For example, when an air bearing is adopted as the steering torque reproduction mechanism, each air bearing pad 4 may be provided not on the bottom surface of the bottom wall 311 of the turning portion 31 of the gantry 3 but on the upper surface of the movable table 321 of the slide portion 32. In this case, each air bearing pad 4 arranges a plurality of ejection holes 41 to face the bottom surface of the bottom wall 311 of the turning portion 31 and dispose them on the upper surface of the movable table 321. Further, the plurality of ejection holes 41 are arranged so that the floating amount of the turning portion 31 during turning varies depending on the turning angle and the resistance to the turning motion does not change. Furthermore, each air bearing pad 4 can also be incorporated into the movable table 321 so as to form the upper surface portion of the movable table 321.

[0034] In addition, the turning portion 31 of the gantry 3 not only supports the dynamometer 2 so as to be turnable with respect to the slide portion 32, but also can be provided with a tilting support portion that supports the dynamometer 2 so as to be tiltable in the axial direction of the rotor shaft of the load motor with respect to the vertical direction, similar to the dynamometer unit previously developed by the applicant.

Explanation of Reference Numerals

[0035] 1... Dynamometer unit, 2... Dynamometer, 21... Case, 211... Peripheral wall portion, 212... End wall portion, 3... Gantry, 31... Turning portion, 313... Turning shaft, 32... Slide portion, 324... Brake disk, 325... Brake caliper, 325a... Brake pad, 326... Plate, 313... Turning shaft, 5... Pressurized air supply adjustment means.

Claims

1. A dynamometer unit provided in a chassis dynamometer device for simulating and evaluating the driving performance of a motor vehicle, The dynamometer unit is replaced with the driving wheels of the motor vehicle and attached to the driving wheel connection part of the motor vehicle. It is housed in a tire house and includes a dynamometer incorporating a load motor that applies torque to the driving wheel connection part of the motor vehicle, and a pedestal to which this dynamometer is connected and that supports the dynamometer at least rotatably. In the dynamometer, The load motor is housed in a case having a peripheral wall portion and an end wall portion covering one end face of the peripheral wall portion, The pedestal has a swivel shaft vertically provided downward from the central portion of the bottom surface, a swivel portion to which the case of the dynamometer is connected, and a slide portion that pivotally supports the swivel shaft of the swivel portion and is slidable in both the vehicle width direction and the vehicle length direction on the installation surface of the dynamometer unit. In a state where the case of the dynamometer is connected to the swivel portion, the swivel portion is rotatable with respect to the slide portion. In this case, The pedestal is provided with a steering torque reproduction mechanism that adjusts the resistance to the turning motion when the swivel portion turns together with the dynamometer by steering the steering wheel of the motor vehicle, and reproduces the steering torque of the steering wheel according to the vehicle speed of the motor vehicle. A dynamometer unit characterized by this.

2. The steering torque reproduction mechanism includes a pressurized air supply adjustment means that supplies pressurized air between the bottom surface of the swivel portion of the pedestal and the upper surface of the slide portion, and adjusts at least one of the pressure and flow rate of the pressurized air to adjust the resistance. The dynamometer unit according to claim 1, characterized by this.

3. In the pedestal, the upper surface of the slide portion is sized such that the bottom surface of the swivel portion does not protrude even during turning. The dynamometer unit according to claim 2, characterized by this.

4. The steering torque reproduction mechanism includes a brake disk arranged parallel to the slide portion and fixed to the swivel shaft of the swivel portion, and a brake caliper incorporating a pair of brake pads that sandwich the brake disk from above and below. The dynamometer unit according to claim 1, characterized by adjusting the braking force of the brake disk by the brake pads to adjust the resistance.

5. The dynamometer unit according to claim 4, characterized in that a plate having a friction coefficient on the upper surface set to a minimum value during running of the automobile is interposed between the bottom surface of the turning portion of the gantry and the upper surface of the slide portion in the steering torque reproduction mechanism.

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