Measuring and testing – Dynamometers – Responsive to torque
Reexamination Certificate
2001-02-02
2004-08-10
Noori, Max (Department: 2855)
Measuring and testing
Dynamometers
Responsive to torque
Reexamination Certificate
active
06772644
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to systems for testing electrical and mechanical energy transfer systems that exhibit vibratory and other responses to electrical or mechanical input energy, and more particularly, to an arrangement that isolates a mechanical or electrical system under test and produces signals and data corresponding to a plurality of operating characteristics of the system under test in response to the input energy.
2. Description of the Related Art
Noise testing of gears to date has been attempted by methods that rigidly mount the gear or axle assemblies in one or more planes. Some other previous attempts chose to have one of the rigidly mounted planes resonate at a frequency sympathetic to gear noise. None of these methods, or any other rigidly mounted test system has been successful. This is due to the lack of repeatability of the previous systems, largely as a result of interacting resonances, and external background noise that is transferred through the rigid mounting system. This is especially true in a production test environment.
These deficiencies in the prior art are most evident in the axle industry. At this time, the only widely accepted way of measuring gear noise is to acquire an assembled axle and install it in a test car. A specially trained individual then drives the car over its typical operating range while carefully listening for axle gear noise. The individual rates the quality of axle gear noise on a scale that is typically 0 to 10. Ten is usually a perfect axle, i.e. one that has no gear noise. This method is made difficult by:
1 The lack of available trained noise rating individuals
2 The cost of test cars.
3 The lack of quality roads or test tracks on which to perform a repeatable and accurate test.
4 The time required for each test.
5 The subjectivity that humans bring into the rating system
Typically less than a dozen axles can be tested by a major manufacturer in one shift due to all of the above complications. This low number is not statistically valid when it is considered that most manufacturers make thousands of axles each day. Even with all of the above problems, human testers in cars are the only widely accepted method of axle testing in the industry due to the lack of a better more reliable testing method. This lack of a scientific basis for rating axles and gear systems is made worse when the reader considers that modern cars are extremely quiet, and are evolving to become more quite. This market direction increases the pressure on axle and other gear manufacturers to make their products quieter. There is a need for a system that offers gear and axle manufacturers a repeatable, reliable, accurate and practical way of measuring gear noise in production or laboratory environments.
It is, therefore, an object of this invention to provide a system for testing an energy transfer system, such as a vehicle axle, quickly and inexpensively, and achieving repeatable results.
SUMMARY OF THE INVENTION
The foregoing and other objects are achieved by this invention which provides, in a first apparatus aspect thereof, a drive coupling arrangement for transmitting substantially exclusively torque from a drive arrangement to a gear assembly under test. In accordance with the invention, the drive coupling arrangement is provided with a first coupler portion attached to the gear assembly under test. The coupler has a polygonal cross-sectional configuration that extends continuously over a predetermined length of axis. The polygonal cross-sectional configuration has a plurality of substantially planar surfaces that extend parallel to the predetermined length of axis. In addition, there is provided a second coupler portion with an internal cross-sectional configuration that accommodates the polygonal cross-sectional configuration of the first coupler portion. The second coupler portion has a plurality of engagement portions that communicate exclusively with a predetermined number of the substantially planar surfaces of the first coupler portion. The second coupler is axially translatable along the first coupler portion for a portion of its predetermined length of axis. In this manner, the first and second coupler portions exert a torque against one another via the substantially planar surfaces of the first coupler portion and the engagement portions of the second coupler portion, over a predetermined range of the portion of the predetermined length of axis. In addition, a resilient insert is installed within the second coupler portion for limiting the extent of axial translation between the plurality of engagement portions of said second coupler portion along said first coupler portion.
In one embodiment of the invention, the first coupler portion is in the form of an assembly nut of the gear assembly under test at a rotatory terminal thereof. The polygonal cross-sectional configuration corresponds to a hexagon and has six substantially planar surfaces. The second coupler portion has three engagement portions that engage three respective substantially planar surfaces of the first coupler portion. The second coupler portion is coupled to the drive arrangement.
A resilient biasing element urges the second coupler portion axially toward the first coupler portion. The predetermined length of axis is substantially vertically arranged, the first coupler portion being disposed axially superior to the second coupler portion. The resilient biasing element urges the second coupler portion axially upward toward the first coupler portion, whereby the first coupler portion communicates axially with the resilient insert. In a specific illustrative embodiment of the invention, the resilient insert is formed of ultra-high molecular weight polyethylene and absorbs axial loading between the first and second coupler portions.
In accordance with a further apparatus aspect of the invention, there is provided an arrangement for isolating an energy transfer system while it is subjected to a test process for noise, the energy transfer system being of the type having an energy input and at least one energy output. In accordance with the invention, the arrangement is provided with a base for supporting the arrangement and the energy transfer system. An isolation support supports the energy transfer system whereby the energy transfer system is translatable in at least one plane of freedom with respect to the base. Additionally, an engagement arrangement is provided for securing the energy transfer system to the isolation support, the engagement arrangement having a first position with respect to the base wherein the energy transfer system is installable on, and removable from, the isolation support, and a second position wherein the energy transfer system is secured to the isolation support. A first coupler portion is attached to the gear system, the coupler portion having a polygonal cross-sectional configuration that extends continuously over a predetermined length of axis. The polygonal cross-sectional configuration has a plurality of substantially planar surfaces that extend parallel to the predetermined length of axis. There is additionally provided a second coupler portion having an internal cross-sectional configuration that accommodates the polygonal cross-sectional configuration of the first coupler portion. The second coupler portion has a plurality of engagement portions that communicate exclusively with a predetermined number of the substantially planar surfaces of the first coupler portion, and are axially translatable along the first coupler portion for a portion of the predetermined length of axis. Thus, the first and second coupler portions exert a torque against one another via the substantially planar surfaces of the first coupler portion and the engagement portions of the second coupler portion.
In one embodiment, there is further provided an energy supply coupled to the energy transfer system for supplying energy thereto when the engagement arrangement is in the second position. The energy transfer
Juranitch James C.
Olschefski Robert D.
Noori Max
Rohm & Monsanto, PLC
Veri-Tek International Corp.
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