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Viewing 7621 to 7641 of 7641
1934-01-01
Technical Paper
340006
W. Briggs, M. L. Fox
1933-01-01
Technical Paper
330042
O. E. Kurt
THIS paper presents the solution of the factors in tires and wheels that cause a particular type of front-end vibration termed “tramp,” which is a vertical vibration of the front axle accompanied by a small degree of simultaneous oscillation of the wheel assembly about the king pin. This vibration in turn sets up the disturbance of the body and chassis. The front-axle vibration is caused by the unbalance and variation in rolling radius of the rotating front-wheel assemblies. The theoretical action of these two factors is developed in detail and supported by experimental results. The foregoing two factors act independently. The resultant of the two periodic forces which they set up depends on their phase relationship.
1932-01-01
Technical Paper
320050
C. L. Humphrey
INSULATING of automobile bodies against noise and heat has been made more complicated by the trend toward lower and more compact bodies and larger and more powerful engines, as more noise and heat are created and must be excluded from the body. Development of the all-steel body also has presented a new problem that calls for different treatment than the composite steel and wood body. Elimination of noise and heat from the body is the mutual problem of the chassis and the body engineers and must be attacked jointly, correction of the trouble being made at the most logical and practical places. Much successful work has been done in the last few years to eliminate noise and heat, but much more can be accomplished by further concentrated effort. After listing the more objectionable chassis noises which have received most attention, the author considers the remaining noise and the heat against which the body must be insulated.
1931-01-01
Technical Paper
310026
Harry F. Huf, J. R. Sabina, J. Bennett Hill
MEASURING knock-sound intensity by a microphone and vacuum-tube amplifying set is described in this paper. Widely varying fuels are compared with mixtures of normal heptane and iso-octane at knock intensities ranging from incipient knock to a knock severe enough to cause preignition. The conclusion is drawn that, for tests on the L-head Cooperative Fuel-Research knock-testing engine, the intensity of knock at which tests are made does not affect the knock ratings if a fuel-matching method is used.
1931-01-01
Technical Paper
310014
A. D. Gardner
STATING the automotive cooling-fan problem as being constituted of the delivery of more air, decrease of fan horsepower, reduction of fan noise so that it is comparable with or less than other powerplant noises and the installation of the fan in a restricted space, the author describes the testing apparatus and method used in analyzing the subject. Fan speeds and the most effective number of blades are then considered, followed by analyses of fan diameter and pitch and curvature of fan blades. The manner in which air is discharged from the fan and the adaptation of a fan to an automobile are also discussed. Following statements concerning the desirable number of fan blades and blade spacing, noise characteristics of fans are analyzed in detail as a preface to the author's consideration of means of reducing fan noise, and a summary listing the conclusions reached as a result of the study is appended.
1929-01-01
Technical Paper
290043
A. B. Cox
1928-01-01
Technical Paper
280052
W. T. DONKIN
A PAPER on Valve-Spring Surge,2 by Mr. Donkin and H. H. Clark, which was presented at the Semi-Annual Meeting of the Society in May, 1927, was presented during the last season by Mr. Donkin at Section meetings in Buffalo, Chicago and Milwaukee. At a meeting of the Cleveland Section he delivered a paper on Valve-Spring Design, part of which is printed herewith. The remainder was a duplication of the Semi-Annual Meeting paper. At each of these Section meetings the subjects of valve-spring surge and valve-spring design were discussed. Some of the discussion was upon part of the original paper in which were compared two valve-springs, the original design vibrating noisily and the improved design being satisfactory.
1928-01-01
Technical Paper
280048
H. A. HUEBOTTER
In this article the author presents analytical methods for determining the unbalanced inertia force and the tangential effort in a line engine. These methods are thought to be of interest for investigation of the effects of various engine design-features on its vibration characteristics. An equation for the resultant reciprocating force is set forth and methods of expressing the inertia and fluid-pressure torque are given. The determination of minimum and maximum resultants and the balance of inertia and fluid-pressure torques are other topics dealt with. The results of a series of analyses are incorporated in tabular form.
1927-01-01
Technical Paper
270044
B. LIEBOWTZ
1926-01-01
Technical Paper
260047
BENJAMIN LIEBOWITZ
Of all the aspects of vibration, acceleration is recognized as of fundamental importance in the riding-qualities question, and the full significance of the problem of measuring acceleration is now also recognized. The author deals with one method, the use of contact-accelerometers, and describes the characteristics of this type of instrument. He then points out that as contact accelerometers were originally designed for vertical motion it was intended to use the upper contact, making full use of the sensitiveness of this contact. However, this very excellence proves to be a detriment and a source of error in the measurement of comparatively large movements. Among other schemes, the use of the lower contact has been suggested as a means for overcoming interference from vibrations of high frequency and small amplitude.
1926-01-01
Technical Paper
260038
FLOYD A. FIRESTONE
Research methods applied to the inspection of automotive parts for noise-producing causes are analyzed by the author, who notes the increasing tendency toward the use of sound-measuring instruments and discusses first the units of sound intensity and loudness. The dyne per square centimeter is a convenient size of unit for measuring the pressure amplitude of sound-waves, since 1 dyne per sq. cm. lies within the range of amplitudes at which the ear normally functions, being approximately that at one's ear when listening to conversation. In calibrating at high frequencies, the thermophone is used. It consists of a small strip of thin platinum or gold a few centimeters long and about 1 cm. wide through which an alternating current of desired frequency is sent.
1925-01-01
Technical Paper
250005
C E SUMMERS
Smooth operation of motor cars becomes increasingly important as average driving-speeds become higher and as the public demands greater luxury and freedom from vibration. An analysis of vibration shows that it is caused by forces which can be calculated with considerable accuracy. Vibration itself is very complex, due to the inter-relation of forces, deflection and periodicity in the parts of the engine. In this paper a number of indicating and recording instruments devised for recording the actual resultant vibration and determining its exact character are described and their operation explained. Vibration due to unbalance of rotating parts, piston unbalance inherent in four-cylinder engines, bending of the crankshaft, centrifugal force, and torsional periods are discussed. Indicator-diagrams of the various kinds of vibration are shown. Unbalanced force and elastic reaction are the two general causes of vibration.
1925-01-01
Technical Paper
250040
EARLE BUCKINGHAM
Discordant sounds from transmission gears can be avoided by using gear-tooth ratios that give pleasing combinations of tones; a 5:6 ratio produces a minor third note; a 4:5 ratio, a major third; a 2:3 ratio, a perfect fifth; and a 2:1 ratio, an octave. Careful attention to selection of relative tooth-numbers, therefore, will aid greatly in the production of quiet or un-objectionable transmissions. Careful design and accuracy in the production of gears will not, alone, insure quiet operation; the shafts must be sufficiently rigid to hold the gears in proper operating position and large flat surfaces in transmission cases, which act as sound amplifiers, should be avoided. Bearings may also be noisy through faults of their own or because of improper mounting and alignment.
1923-01-01
Technical Paper
230042
T J LITLE
Previous efforts to obtain comfortable riding-qualities for passenger-carrying automobiles are mentioned, and a device that combines a recording seismograph and a spring-action recorder is illustrated and described, since such a device is essential in conducting investigations of this character. Methods governing the use of the device when studying spring action and chassis vibration are outlined, and the results obtained are presented graphically and discussed. Several unique features characterize these tests and are worthy of consideration, not only because of the results obtained thereby but as being good illustrations of what can be accomplished by substituting unusual and perhaps spectacular methods in special instances for ordinary practice that has failed to produce some desired result.
1922-01-01
Technical Paper
220055
H J CRAIN, J BRODIE
While investigating the sources and causes of noise in automobiles during an extensive connection with one of the largest automobile companies, the authors recorded their experiences in the shop in the form of notes. Some of these are offered with a view to stimulating the discussion of the subject and with the hope that additional information will be brought out by an exchange of ideas, particularly on the problem of eliminating gear-noises. In many cases they found that noise was caused by failure to allow sufficient clearance for an adequate oil-film. And it was noted frequently that when one noise had been located and silenced another appeared that had not been apparent before. The topics that have been considered include the running-in of brake-bands, engine knocks, oil-pump gear-noise and that of gears in general, the clearances of ball bearings, backlash, and rear-axle bevel-gears.
1922-01-01
Technical Paper
220056
K L HERRMANN
The different gear noises are classified under the names of knock, rattle, growl, hum and sing, and these are discussed at some length, examples of defects that cause noise being given and a device for checking tooth spacing being illustrated and described. An instrument for analyzing tooth-forms that produce these different noises is illustrated and described. Causes of the errors in gears may be in the hardening process, in the cutting machines or in the cutters. A hobbing machine is used as an example and its possibilities for error are commented upon. Tooth-forms are illustrated and treated briefly, and the hardening of gears and the grinding of gear-tooth forms are given similar attention.
1921-01-01
Technical Paper
210018
S E SLOCUM
1920-01-01
Technical Paper
200072
F M LEWIS
Vibrations of several kinds can occur in crankshafts, but the principal ones are transverse and torsional; the paper deals entirely with the latter. A simple case of torsional vibration is considered first and the principles are applied to the torsional vibration of a shaft, the argument being carried forward at some length. A discussion of critical speeds follows and this is supplemented by a lengthy mathematical analysis, inclusive of diagrams. Calculations were made to determine the period of the shafting of United States submarines S4 to S13 and these are described. The three cases investigated include the charging condition when the engine is driving the dynamo, the after clutch being disconnected; the surface condition, when the engine drives the propeller; and the submerged condition, when the motors drive the propeller, the forward clutch being disconnected. Calculations were made also with a Sperry magnetic clutch substituted for the usual flywheel and clutch.
1920-01-01
Technical Paper
200009
BENJAMIN LIEBOWITZ
The five fundamental criteria of the performance of a motor vehicle as a whole are stated. Riding comfort is investigated at length with a view to determining methods of measurement of the two classes of vehicle vibrations that affect the riding qualities of a car, so that suitable springs can be designed to overcome them. The underlying principles of the seismograph are utilized in designing a specialized form of this instrument for measuring vehicle vibrations, the general design considerations are stated and a detailed description is given. This is followed by an explanation of the methods used in analyzing the curves obtained, thus making possible a standardized measurement of riding comfort. The factors determining riding comfort are then analyzed in connection with spring-development work, the most important are summarized and the preliminary experimental results of those directly determined by the seismograph are outlined.
1912-01-01
Technical Paper
120006
ERNEST R. FRIED
1908-01-01
Technical Paper
080003
JOHN MAGEE ELLSWORTH, THOMAS J. FAY
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