JP4496054B2 - Chassis dynamometer - Google Patents

Description

  The present invention relates to a chassis dynamometer, and more particularly to a structure of a chassis dynamometer roller suitable for noise measurement.

  As the chassis dynamometer, a roller that simulates a road surface with respect to a vehicle driving wheel, a dynamometer that rotates and drives the roller, and a torque that is applied to the dynamometer via the roller by the vehicle driving wheel. A chassis dynamometer including a load cell that measures a load applied to an arm connected to a dynamometer is known.

Moreover, in such a chassis dynamometer, as a technique for setting the property of the road surface to be simulated by a roller, a block-like segment for simulating road irregularities is formed on a vehicle driving wheel mounting surface of the roller by a bolt or the like. A technique for mounting is known (for example, Patent Document 1).
No. 05-28508

  Now, in order to reduce the noise of automobiles and to realize comfortable driving sounds, it is necessary to measure and correctly evaluate the sounds generated from the automobile itself, such as the engine, suspension and chassis of the automobile during driving. On the other hand, sound (a kind of so-called road noise) generated between a road surface simulated by a roller and an automobile tire hinders measurement and evaluation of the sound generated from the automobile itself.

  Therefore, an object of the present invention is to provide a chassis dynamometer that can further reduce the noise generated between a road surface simulated by a roller and a tire of an automobile.

  In order to achieve the above object, according to the present invention, a chassis dynamometer roller having a roller simulating a road surface with respect to a vehicle tire is provided with a plurality of holes having a hollow cylindrical shape penetrating between inner and outer peripheral surfaces. A frame, a road surface simulation layer for simulating the road surface of the tire provided on the outer peripheral surface of the frame so as to cover the outer peripheral surface, and a sound absorbing member provided to cover the inner peripheral surface of the frame It consists of a layer of material.

  According to such a chassis dynamometer, part of the contact sound between the automobile tire and the road surface that has passed through the road surface simulation layer and reached the outer peripheral surface of the frame vibrates the frame, and the other part It passes through the holes provided in the frame and proceeds to the layer of sound absorbing material. The sound that has advanced to the sound absorbing material layer is absorbed by the sound absorbing effect of the sound absorbing material layer. Further, the vibration of the frame and the sound generated by the vibration are attenuated and absorbed by the road surface simulation layer and the sound absorbing material layer on both sides of the frame.

Therefore, according to this embodiment, generation | occurrence | production of the reflected sound etc. in a flame | frame can be suppressed effectively, and the sound generated between a tire and a roller can be reduced favorably.
Here, in the above chassis dynamometer, it is desirable that the road surface simulation layer of the roller be a porous layer or a layer having high porosity. That is, the road surface simulation layer of the roller may be, for example, a porous or highly porous layer formed by paving the outer peripheral surface of the frame with an asphalt mixture.

  By doing in this way, the air pushed between the tire and the road surface simulated by the road surface simulation layer is diffused as it is into the porous, high porosity, low noise pavement layer, and further, the holes arranged in the frame Escape into the layer of sound absorbing material. Therefore, the generation of sound (air pumping sound) due to the ejection of compressed air compressed between the tire and the road surface, and the noise caused by reflection of the sound generated between the tire and the road surface are suppressed.

  In order to achieve the above object, the present invention provides a chassis dynamometer including a roller that simulates a road surface with respect to a tire of a vehicle. The roller is arranged on a cylindrical frame and an outer peripheral surface of the frame. A road surface simulation layer having a porous or high porosity property that simulates the road surface with respect to the tire and is provided so as to cover the surface.

  By doing in this way, the air pushed in between the tire and the road surface simulated by the road surface simulation layer is diffused as it is into the porous, high porosity, low noise pavement layer. Therefore, it is possible to suppress the generation of sound (air pumping sound) due to ejection of air that is crushed and compressed between the tire and the road surface.

  As described above, according to the present invention, it is possible to further reduce the sound generated between the road surface simulated by the roller and the automobile tire.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 schematically shows the overall configuration of the chassis dynamometer according to the present embodiment. Here, FIG. 1 a shows a schematic top view of a pit with a chassis dynamometer, and FIG. 1 b shows a schematic side view of a pit with a chassis dynamometer. 1c is a side view of the chassis dynamometer, FIG. 1d is a top view of the chassis dynamometer, and FIG. 1e is a front view of the chassis dynamometer. The back of the chassis dynamometer is as shown in FIG. 1b.

In the illustrated example, two chassis dynamometers 1 are provided in the pit 10 corresponding to the respective vehicle driving wheels. These chassis dynamometers 1 are used to measure various characteristics of the automobile advanced on the pit 10 with the chassis dynamometer.
That is, the chassis dynamometer has, as main components, a roller 2, a dynamometer 3 that rotationally drives the roller 2, two arms 4 that are connected to both sides of the frame of the dynamometer 3, a load cell 5, and a base 6. The roller 2 is connected to the shaft of the dynamometer 3, and the dynamometer 3 is supported so as to be swingable with respect to the base 6.

  Then, the chassis dynamometer 1 is arranged such that the automobile driving wheel of the automobile advanced on the pit 10 is placed on the roller 2 with the zenith exposed from the opening provided on the automobile running surface of the pit 10, Torque is applied to the vehicle driving wheel via the roller 2 by the dynamometer 3, and torque applied from the vehicle driving wheel to the arm 4 via the roller 2 and the dynamometer 3 is measured by the load cell 5.

  Here, the dynamometer 3 swings with respect to the base 6 in accordance with the torque applied to the roller 2 by the vehicle drive wheels. Therefore, by measuring the load applied to the arm 4 fixed to the dynamometer 3 with the load cell 5, the action between the roller 2 and the vehicle driving wheel can be measured.

  However, as the chassis dynamometer 1 according to this embodiment, instead of using two chassis dynamometers 1 each having one roller 2 and one dynamometer 3, vehicle driving wheels are mounted one by one. The chassis dynamometer 1 including two rollers 2 and one dynamometer 3 that rotationally drives the two rollers 2 may be used.

Next, FIG. 2 shows the structure of the roller 2.
2a is a side view of the roller 2, FIG. 2b is a front view, and FIG. 2c is a cross-sectional view taken along the cutting line AA in FIG. 2b.
The upper surface and the lower surface of the roller 2 appear in the same manner as the side surface, and the back surface of the roller 2 appears in the same manner as the front surface.
As shown in the drawing, the roller 2 is composed of two disk-shaped metal disk parts 21 that respectively form two cylindrical bottom surfaces of the roller 2, and a substantially hollow cylindrical metal that forms the cylindrical side surface of the roller 2. The roller frame 22 made of steel, the low noise pavement layer 23 provided on the outer peripheral surface so as to cover the outer peripheral surface of the roller frame 22, and the inner peripheral surface of the roller frame 22 so as to cover the inner peripheral surface of the roller frame 22 And the sound absorbing material layer 24 formed.

  Now, the disk part 21 is a disk-shaped member having a central hole for allowing the shaft 20 of the dynamometer 3 to pass through in the center, and the two disk parts 21 pass through the shaft 20 through the central hole, and between the rollers The frame 22 is sandwiched between the flanges fixed to the shaft 20 with bolts or the like. Further, a roller frame 22 provided with a low noise pavement layer 23 on the outer peripheral surface and a sound absorbing material layer 24 fixed on the inner peripheral surface is a flange portion provided at two open end portions of a hollow cylindrical shape, It is fixed to the disk part 21 with bolts.

Here, as shown in a perspective view of the roller frame 22 in FIG. 2 d, a number of through holes 221 are provided in the wall forming the side surface of the roller 2 of the roller frame 22.
2d shows an enlarged schematic view of the cross section of the roller 2 in FIG. 2c, the low noise pavement layer 23 is an asphalt pavement layer having a porosity increased to about 20% or more. Pavement with asphalt mixture of 80% aggregate (crushed stone), 10% fine aggregate (sand) and 10% asphalt (modified asphalt) so that the outer peripheral surface of the roller frame has a layer thickness of about 20-100mm It is formed by welding and construction. In addition, this low noise pavement may be called a highly functional pavement, a drainage pavement, a water-permeable pavement, etc. Here, as shown in the figure, the low noise pavement layer 23 is porous and has high porosity.

Next, the sound absorbing material layer 24 is a layer of a sound absorbing material such as felt, glass wool, rock wool, or urethane foam.
Now, according to the chassis dynamometer 1 using such a roller 2, when measuring the sound generated by the automobile while driving the automobile with the driving wheel of the automobile placed on the roller 2, Sound generated with the roller 2 can be greatly reduced.
In other words, one of the noise generation mechanisms between the tires and the road surface of automobiles, such as the generation of sound (air pumping noise) generated by the squeezed and compressed air between the tires and the road surface, and automobiles According to the present embodiment, noise caused by acoustic reflection on the road surface and the surface of the metal roller frame 22 of the sound and engine sound generated between the tire and the road surface is suppressed as follows.

  In the roller 2 of the present embodiment, the air pushed between the road surfaces formed by the outer peripheral surface of the low noise pavement layer 23 of the roller 2 as the tire rotates with the roller 2 is porous and has a high porosity. In the case where it is diffused into the low noise pavement layer 23 and the degree of pressing is large, it further escapes into the sound absorbing material layer 24 from the through hole 221 provided in the roller frame 22. Therefore, the generation of air pumping noise is suppressed.

  In addition, the contact noise between the tires of the automobile and the road surface, the engine sound of the automobile reaching the road surface, etc. are low in the low-noise pavement layer 23 having porosity, low acoustic reflectivity due to high porosity, and sound absorption. Attenuates as it travels inside. Further, a part of the sound reaching the outer peripheral surface of the roller frame 22 is reflected by the outer peripheral surface and is again absorbed by the sound absorbing effect of the low noise pavement layer 23. On the other hand, a part of the remaining sound reaching the outer peripheral surface of the roller frame 22 vibrates the roller frame 22, and the other part is transmitted through a large number of through holes 221 provided in the roller frame 22 to transmit the sound absorbing material layer 24. Proceed to The sound that has advanced to the sound absorbing material layer 24 is absorbed by the sound absorbing effect of the sound absorbing material layer 24. Further, the vibration of the roller frame 22 and the vibration sound are transmitted to the low noise pavement layer 23 and the sound absorbing material layer 24 on both sides of the roller frame 22 and are attenuated and absorbed.

Therefore, according to this embodiment, the sound generated between the tire and the roller 2 can be satisfactorily reduced.
By the way, in this embodiment, although it showed about the chassis dynamometer 1 for four-wheeled vehicles, the roller 2 shown by this embodiment is applicable similarly to the two-wheeled vehicle and other arbitrary vehicle chassis dynamometers. .
Further, in the above embodiment, the low noise pavement layer 23 using the asphalt mixture is provided on the outer peripheral surface of the roller frame 22, but instead of the low noise pavement layer 23, a layer of foaming synthetic rubber or You may make it provide the layer by the arbitrary materials which have porous or high porosity, such as a layer of a foamable synthetic resin.

  Further, in the present embodiment, instead of the low noise pavement layer 23, a layer having low acoustic reflectivity such as a layer of synthetic rubber or a layer of synthetic resin that is not porous or highly porous is provided. good. Even in this case, sound is diffused while suppressing acoustic reflection from the outer peripheral surface of the roller frame 22 by the large number of through holes 221 provided in the roller frame 22 and the sound absorbing material layer 24 provided on the inner peripheral surface side of the roller frame 22. It can absorb sound and obtain a certain silent effect.

It is a figure which shows the chassis dynamometer which concerns on embodiment of this invention. It is a figure which shows the structure of the roller of the chassis dynamometer which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Chassis dynamometer, 2 ... Roller, 3 ... Dynamometer, 4 ... Arm, 5 ... Load cell, 6 ... Base, 10 ... Pit, 20 ... Shaft, 21 ... Disc parts, 22 ... Roller frame, 23 ... Low noise property Pavement layer, 24 ... sound absorbing material layer, 221 ... through hole.

Claims (3)

A chassis dynamometer equipped with a roller that simulates a road surface with respect to a vehicle tire,
The roller is
A hollow cylindrical frame having a plurality of holes penetrating between the inner and outer peripheral surfaces;
A road surface simulation layer for simulating a road surface with respect to the tire provided to cover the outer peripheral surface on the outer peripheral surface of the frame;
A chassis dynamometer comprising a sound absorbing material layer provided to cover an inner peripheral surface of the frame. The chassis dynamometer according to claim 1,
The chassis dynamometer, wherein the road surface simulation layer is a porous layer or a layer having high porosity. A chassis dynamometer according to claim 2,
The chassis dynamometer is characterized in that the road surface simulation layer is a layer formed by paving the outer peripheral surface of the frame with an asphalt mixture.