JPS61124844A - Low noise type chassis dynamometer - Google Patents

Abstract

PURPOSE:To suppress the noise value in a test room to a small degree, by providing a vibration damping material to a drum and forming the bearing of the drum from a synthetic resin and further providing a sound absorbing material to each place. CONSTITUTION:The tire 2 of a test vehicle 1 is mounted on a drum 3 while the drum 3 is supported by bearings 4 and fixed to a foundation 10 through bearing stands 5. A torque detector 6 is connected to the shaft end of the drum 3 through a coupling 7 to detect the driving force generated from the test vehicle 1. As the coupling, in order to block the vibration propagating through the shaft system, a rubber coupling is used. As the material quality of the bearings 4, a synthetic resin is used and sound absorbing materials 11 are provided to the bottom surface and side surface of the foundation 10 and the lower side of a pit cover 14. Further, vibration damping materials are adhered to the back sides of the outer peripheral plate of the drum 3 and the side plates of said drum 3 to provide damping effect to vibration.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a low-noise chassis dynamometer suitable for indoor noise tests between various vehicles.

[Background of the invention]

Conventional equipment involves attaching vibration damping material directly to the drum, improving the accuracy of drum support bearings and using low-noise materials for cages, couplings to isolate shaft-propagated vibrations from gear devices, etc. There are no low-noise chassis dynamometers in which the method of attaching sound-absorbing materials to each part is done at the same time. However, one in which noise countermeasures are partially applied to the drum or pit etc. is disclosed, for example, in Japanese Utility Model Application Publication No. 53-82902. ,
This is known from Japanese Utility Model Application Publication No. 54-15021.

[Purpose of the invention]

An object of the present invention is to provide a low-noise chassis dynamometer that takes overall noise countermeasures into consideration.

[Summary of the invention]

First, the structure is designed to reduce noise from the main body, such as the drum and drive system, and the noise generated by this structure is secondarily absorbed inside the pitcher.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a plan view of the chassis dynamometer, and FIG. 2 shows a front view. Reference numeral 1 designates a vehicle to be tested, and its drive side tires 2 are mounted on a drum 3, which is a virtual road surface. The drum 3 is supported by bearings 4 and 5, each mounted on a bearing stand 5, and fixed to a foundation 10. A torque detector $6 is connected to the shaft end of the drum 3 via a coupling 7 to detect the driving force generated from the test vehicle 1. This coupling is a special type, such as a rubber coupling, which insulates vibrations propagating through the shaft system. Reference numeral 13 is a wall that separates a room for testing vehicles from a room for installing mechanical equipment, and connects the flywheels 8 through a hole with a slight gap through which the shaft coming out of the coupling 7 passes. The flywheel 8 is an inertial body corresponding to the weight of the test vehicle, and is composed of several disks, and the necessary disks are selected as appropriate depending on the weight of the test vehicle and are connected to the rotating shaft. This provides resistance when the test vehicle accelerates and then re-brakes to decelerate. Reference numeral 9 indicates a dynamometer, which provides the resistance of rolling, wind, and slope that the test vehicle 1 experiences during steady running. With this kind of configuration, it is possible to reproduce driving conditions on the road and indoors. Reference numeral 10 indicates a foundation for installing the drum area under the floor, and reference numeral 14 indicates a pit cover for filling the space other than the drum. 11 is the bottom of the foundation 10.

Figure 3 shows the sound absorbing material attached directly to the wall surface and the lower side of the pit cover 14. Figure 3 shows a cross-sectional view of the drum 3. Reference numeral 12 shows the sound absorbing material attached to the back and side plates of the outer circumferential plate of the drum 3 to reduce the vibration of the plate. It has a damping effect on the

Here, the effect of low noise will be explained. Since we are conducting an iFF study of the noise inside the test vehicle or the noise generated from the vehicle at a remote location outside the vehicle, the noise on the test machine side must be kept extremely low. Noise generated from flywheel dynamometers, etc. is mainly caused by
3, the vibration propagating through the shaft becomes the cause, so the rubber coupling 7 completely blocks out the vibration.

Next, the bearing that supports the drum is a source of noise, so the noise can be reduced by using a high-precision bearing, and by using a synthetic resin material to suppress the noise generated by the sliding phenomenon between the retainer and the bearing. . or.

By again applying a vibration distribution material as shown in FIG. 3 to the plate of the drum, it is possible to prevent noise generated by rotational vibration of the plate. As an additional treatment, sound-absorbing materials are installed around the foundation where the drum is installed and at the bottom of the pit cover to absorb the noise that reverberates inside the pit.In general, when comparing the results when traveling at 50 km/m, no noise countermeasures are taken. If not,
The noise will be about 65 dB (A), but according to the present invention, it will be about 45 dB (A).
The noise of the test vehicle can be reduced to about dB (A).
experiments and research can be carried out easily.

[Brief explanation of drawings]

FIG. 1 is a plan view showing the overall structure of the chassis-dynamometer of the present invention, FIG. 2 is a front view of FIG. 1, and FIG. 3 is a cross-sectional view of a drum serving as a virtual road surface. DESCRIPTION OF SYMBOLS 1... Test vehicle, 2... Drive tire, 3... Drum, 4... Bearing, 5... Bearing stand, 6... Torque detector, 7... Coupling, 8...・Fly foil,
9... Dynamometer, 10... Foundation, 11... Sound absorbing material,
12... Damping material, 13''''4 1 Figure 2 Figure 3

Claims (1)

[Claims] A chassis dynamometer is equipped with a drum that corresponds to a tread, a movement meter that absorbs the load during steady running on the road, and a flywheel that absorbs the load during acceleration and deceleration. A drum equipped with damping material to isolate vibrations, a bearing made of synthetic resin to reduce noise from the bearing that supports the drum, and a coupling to isolate vibrations propagating from the drive shaft to the drum. A low-noise chassis dynamometer, characterized in that sound-absorbing materials are provided on the pit cover around the drum and on the sides and bottom of the pit to absorb noise within the pit.