Showing papers on "Dynamic Vibration Absorber published in 1986"
TL;DR: In this paper, the steady-state vibration amplitudes of a cantilever beam with vibration absorbers are determined by the assumed-modes method, and the results obtained are presented in graphical form.
59 citations
Patent•
24 Jun 1986
TL;DR: In this paper, an electromagnet is energized by a variable current through at least one coil and it exerts an attractive force on the body which is oscillating due to the vibrations occurring in the first part of the structure.
Abstract: Apparatus for reducing mechanical vibrations in a first part of a structure, in which these vibrations occur through its connection to a part of the structure which is the source of the mechanical vibration. This apparatus comprises an electromagnet rigidly connected to the first part of the structure and a body of magnetizable material connected via a resilient element to the first part of the structure, while an air gap is provided between the electromagnet and the body. The electromagnet is energized by a variable current through at least one coil and it exerts an attractive force on said body which is oscillating due to the vibrations occurring in the first part of the structure. The restoring force exerted by the resilient element on the secondary body has the effect of lowering the resonant frequency of the second body on the resilient element as compared to the resonant frequency of the apparatus when no current passes through the coil. The amount of this lowering can be controlled depending upon the frequency of the exciting vibration by varying the electric current through the coil.
43 citations
TL;DR: In this paper, the effect of a viscously damped dynamic absorber on the dynamic behavior of a linear vibration system with many degrees of freedom is investigated and optimal values for the parameters describing the behaviour of the dynamic absorbers are determined, in order that the transmissibility of the composite system be minimized over the whole frequency range.
40 citations
28 citations
Abstract: A vibration damping arrangement for a structural member including leaf springs extending horizontally from a vibration absorber body adapted to be attached to the structural member. A set of horizontal-vibration-absorbing leaf springs extends in one horizontal plane while a set of vertical-vibration-absorbing leaf springs extends in another horizontal plane. A weight is mounted on the distal end of each leaf spring. The relative positions of the leaf springs in their respective planes are staggered around a vertical axis.
26 citations
Patent•
28 Jul 1986
TL;DR: In this paper, a Stirling engine is mounted on the exterior housing of a hydraulic drive system, and a pair of vibration absorbers are employed, each absorber being formed of apair of leaf spring assemblies, between which the absorber mass is suspended.
Abstract: A vibration absorber unit or units are mounted on the exterior housing of a hydraulic drive system of the type that is powered from a pressure wave generated, e.g., by a Stirling engine. The hydraulic drive system employs a piston which is hydraulically driven to oscillate in a direction perpendicular to the axis of the hydraulic drive system. The vibration absorbers each include a spring or other resilient member having one side affixed to the housing and another side to which an absorber mass is affixed. In a preferred embodiment, a pair of vibration absorbers is employed, each absorber being formed of a pair of leaf spring assemblies, between which the absorber mass is suspended.
24 citations
Patent•
06 Dec 1986
TL;DR: In this article, a vibration absorber is proposed to reduce the predominantly torsional vibrations of rotating shafts, particularly those of passenger vehicle propeller shafts with a relatively high speed of rotation.
Abstract: To reduce the predominantly torsional vibrations of rotating shafts, particularly those of passenger vehicle propeller shafts with a relatively high speed of rotation, the invention proposes a vibration absorber which consists of a supporting body (1) with a fixing flange (2) for connection to the shaft, of a flywheel ring (4) concentrically surrounding the supporting body (1) and of a plurality of segmental rubber springs (5) distributed over the circumference and vulcanised in between the supporting body (1) and the flywheel ring (4), additional elements in the form of roller-shaped rolling elements (8) being provided between the rubber springs to provide radial support for the flywheel ring (4) relative to the supporting body (1). The axially extending rolling elements (8) are composed of dimensionally stable material, have a radial extent which almost corresponds to the radial clearance between the supporting body (1) and the flywheel ring (4) and are supported relative to the supporting ring (1) and the flywheel ring (4) via relatively thin rubber layers (11, 12) with a constant thickness in the circumferential direction. The rolling elements (8) and the rubber layers (11, 12) have an axially extending, relatively shallow wave profile with at least three peaks (18).
14 citations
11 citations
Patent•
21 Aug 1986
TL;DR: In this article, a main vibrating system is constituted of an anvil and springs, a dynamic vibration absorber mass 6 is fitted via a dynamic vibrator spring and a clamp cylinder 8 clamping and holding a guide rod 7 and a viscosity adding means mechanism 9 are provided.
Abstract: PURPOSE:To effectively suppress the shock response by fitting a dynamic vibration absorber mass to a main vibrating system mass via a dynamic vibration absorber and effectively releasing the retention of a holding means applying the initial displacement to it with a shock force foreseeing detector and a control unit. CONSTITUTION:A main vibrating system is constituted of an anvil 1 and springs 2, a dynamic vibration absorber mass 6 is fitted via a dynamic vibration absorber spring 5, and a clamp cylinder 8 clamping and holding a guide rod 7 and a viscosity adding means mechanism 9 are provided. As a foreseeing operation mechanism, a hammer head 3 is detected by a detector 10 such as a photosensor, and the retention of the clamp cylinder 8 is released by a control unit 11, with the delay required for the output of the detector 10 given. This control is applied so that the first wave or the second wave of the damping force by the dynamic vibration absorber 4 coincides timewise with the first wave of the shock force. Accordingly, the shock response can be effectively suppressed.
Patent•
09 Oct 1986
TL;DR: In this paper, a movable mass body is oscillatingly supported between two opposite nonlinear springs, and controlling supporting spaces for said springs in the direction of a spring action line.
Abstract: PURPOSE:To effectively control vibration by oscillatingly supporting a movable mass body between two opposite nonlinear springs, and controlling supporting spaces for said springs in the direction of a spring action line. CONSTITUTION:A movable mass body 21 is oscillatingly supported between nonlinear springs 22, 23. A signal issued from a vibration detecting means 24 is inputted into a controller 25 to control a step motor 16 by means of relation between a previously determined frequency and the position of an arm 10. Said arm 10 is vertically moved to control supporting spaces for said springs 22, 23 in the direction of a spring action line for equalizing the natural frequency of a vibration absorber to the frequency of a main vibrating body. Thus vibration can be effectively controlled.
TL;DR: In this article, a simple low cost design for a holographic table is described which uses rubberised coir as the main vibration absorber and the essential vibration characteristics of the table are discussed.
Abstract: A simple low cost design for a holographic table is described which uses rubberised coir as the main vibration absorber. The essential vibration characteristics of the table are discussed.
01 Jan 1986
TL;DR: In this article, a point absorber type device, damped by a single-acting hydraulic cylinder, has been tested in the laboratory and modeled mathematically, and the system's efficiency was found to be equal that of systems with double-acting pumps.
Abstract: A point absorber type device, damped by a single-acting hydraulic cylinder, has been tested in the laboratory and modeled mathematically. The system’s efficiency was found to be equal that of systems with double-acting pumps. Response and efficiency curves are presented from both the physical and mathematical models for the case of monochromatic wave forcing.
Patent•
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30 Jun 1986
TL;DR: In this article, the authors proposed a bar vibrating body with multiple lugs for a vibrating substance, and set the natural frequency of transverse vibration of this lug higher than the vibration frequency of a motor.
Abstract: PURPOSE: To improve the yielding force and speed, by specifying a bar vibrating body with multiple lugs for a vibrating substance, and by setting the natural frequency of transverse vibration of this lug higher than the vibration frequency of a motor. CONSTITUTION: A vibrating wave motor is composed of a group of piezoelectric elements 1, an elastic body 21 as a vibrating substance, a moving body 3, a supporting vibration absorber 4 and an anchor body 5. By the travelling vibrating wave of a group of piezoelectric elements 1, etc. the moving body 3 coming into contact with the elastic body 21 is forced to move in the direction of an arrow A or in the reverse direction. At this moment, multiple lugs 21A extended from the bottom of the elastic body 21 are provided in the whole circuit of the elastic body 21. The form of the lug 21A is selected so that the natural frequency of the transverse vibration of the beam of this lug 21A may become higher than the vibrating frequency of the motor. Thus, the travelling wave is not disturbed and its yielding force is not reduced even if the length 1 of the lug 21A is elongated and the pressure W to apply is increased. COPYRIGHT: (C)1988,JPO&Japio
Patent•
08 Jul 1986
TL;DR: In this article, a dynamic vibration absorber is mounted to any one of the parts of the crank pulley while composed of one or plural centrifugal pendulums 6a, 6b able to absorb a vibration of the crankshaft 1 in proportion to a speed of the internal combustion engine.
Abstract: PURPOSE:To reduce amplitude of a torsional vibration over the total speed range of an engine, by providing in a crank pulley a dynamic vibration absorber which can absorb the vibration of a crankshaft in proportion to a speed of the internal-combustion engine. CONSTITUTION:An internal-combustion engine provides in the front end part of its crankshaft 1 a crank pulley 2 to be fixed, and the crank pulley 2, having a boss part 21, flange part 22 and an outer ring part 23, provides a dynamic vibration absorber to be arranged in a space region surrounded by these parts. This dynamic vibration absorber is mounted to any one of the parts 21-23 while composed of one or plural centrifugal pendulums 6a, 6b able to absorb a vibration of the crankshaft 1 in proportion to a speed of the internal-combustion engine.
Patent•
13 Nov 1986
TL;DR: In this article, the authors proposed a method to reduce the variation of frequency even if the stroke of a spring is reduced, by constituting the title device from a weight, roller, spring, and a damper and applying the force which is equal to the product of the vertical component of the spring length at the balance position of a Spring in linear spring form and the spring constant onto a spring as initial tension.
Abstract: PURPOSE:To reduce the variation of frequency even if the stroke of a spring is reduced, by constituting the title device from a weight, roller, spring, and a damper and applying the force which is equal to the product of the vertical component of the spring length at the balance position of a spring in linear spring form and the spring constant onto a spring as initial tension. CONSTITUTION:A weight 1 is joined with the upper surface of a construction 4 by a spring 3 and a damper 2, and supported through a roller 5 so as to be shifted in the horizontal plane on the undersurface of the construction 4. The force which is equal to the product of the vertical component of the spring length at the balance position of a spring 3 in linear spring form and the spring constant is applied as initial tension onto the spring 3. Therefore, the stroke of the spring 3 can be reduced, and the frequency of a dynamic vibration absorber can be made constant independently of the magnitude of amplitude. Further, the weight applied onto the roller 5 can be reduced by applying a prescribed initial tension onto the spring 3, and the load applied onto the roller 5 can also be lightened.
Journal Article•
TL;DR: In this paper, a centrifugal pendulum absorber to reduce ship superstructure vibration was developed, which is claimed to be easy to install and can be used in any ship.
Abstract: A centrifugal pendulum absorber to reduce ship superstructure vibration was developed. It is compact and claimed to be easy to install. Vibration of any order caused by engine or propeller can be reduced, random variations of amplitude and phase can be automatically followed, and other structures are not excited by the absorber.
Patent•
26 Mar 1986
TL;DR: In this article, the spring constant of an elastic carrier seat was decreased to increase the capability of isolating vibration by arranging the spring constants of the elastic carriers to be changed in direct response to the condition of a rod surface without depending upon any external control.
Abstract: PURPOSE:To enable the spring constant of an elastic carrier seat to be decreased so that its capability of isolating vibration may be increased, by arranging the spring constant of the elastic carrier seat to be changed in direct response to the condition of a rod surface without depending upon any external control. CONSTITUTION:Liquid holding chambers 5, 6 are formed above and below a rubber-made vibration absorber 4 and both chambers are communicated to each other via a communication hole 7 provided through the center of vibration 4. A control rod 8 having a small cross section in its central portion and both ends formed in large areas via tapered portions is guided through this communication hole 7. One end of said control rod 8 is set to the bottom of liquid holding chamber 5. Since the portion with small cross-sectional area of the control rod 8 is sufficiently smaller than the communication hole 7 in its diameter and no effect of contraction is apparent, the spring constant can be maintained low. Further, since the portion with large cross-sectional area and tapered portions of the control rod 8 are very slightly smaller than the communication hole 7 in diameters, and effect of contraction is apparent, sufficient vibration damping action is available in case of large amplitude of vibration.
TL;DR: In this article, the authors proposed a new vibration controlling method which combines the modal analysis using the finite element method with a design method of dynamic absorbers enlarged to control the vibration of multi-degree-of-freedom systems.
Abstract: In order to effectively suppress a number of resonance peaks occurring in a machine structure, this paper proposes a new vibration controlling method which combines the modal analysis using the finite element method with a design method of dynamic absorbers enlarged to control the vibration of multi-degree-of-freedom systems. This method is essential in order to determine the optimum mounting position of the dynamic absorbers and the equivalent masses in these positions with the aid of modal analysis. If the equivalent masses are obtained, the established design method can be applied to the design of each dynamic absorber. The effectiveness of the method is demonstrated by suppressing the first five resonance peaks of a rectangular plate using the four optimal designed dynamic absorbers.
Patent•
19 Mar 1986
TL;DR: In this paper, a rotary shaft is mounted in a danger-protecting box and rotated on a support face to absorb the vibration energy when the structure is horizontally vibrated.
Abstract: PURPOSE:To effectively absorb vibrations by providing a hollow tube housing a viscous material in it and a rotary shaft penetrating the center of the tube and having a stirrer at a portion located in the tube and stirring the viscous material with the stirrer during the vibration. CONSTITUTION:A vibration absorbing device is constituted with a hollow cylindrical tube 2 filled with a viscous material 1 in it and having sufficiently large weight, a rotary shaft 5 longitudinally penetrating the center of the tube 2 and rotatably supported with bearings 3 and fitted with blades 4 at a portion located in the tube 2, and a mount 7 rotatably supporting both ends of the rotary shaft 5 on circular support faces. The vibration absorbing device is stored in a danger protecting box 8 and is arranged nearly horizontally in relation to a structure 9 so that the axis (i) of the rotary shaft 5 is faced at a right angle to the vibration direction. Accordingly, when the structure 9 is horizontally vibrated, the rotary shaft 5 is rotated on the support face and the blades 5 stir the viscous material 1 to absorb the vibration energy.
Patent•
25 Sep 1986
TL;DR: In this article, the vibration absorber is fixed between the end of a gearbox output shaft and a flexible shaft coupling, and the centering of the vibrator is accomplished by axial projections of the hub spider of the coupling.
Abstract: Arrangement of a vibration absorber in the drive line of motor vehicles, in particular. In this arrangement, the vibration absorber is fixed between the end of a gearbox output shaft and a flexible shaft coupling. The centering of the vibration absorber is accomplished by means of axial projections of the hub spider of the coupling and the centring of the coupling is accomplished by means of a centring hole in the hub spider of the coupling.
25 Sep 1986
TL;DR: In this paper, the effect of Coulomb friction combined with viscous damping in the main system, to which a viscous-damped dynamic vibration absorber is attached, is analyzed.
Abstract: This report presents the effect of Coulomb friction combined with viscous damping in the main system, to which a viscous-damped dynamic vibration absorber is attached. The main system is subjected to harmonic base excitation, and in the analysis, a similar process is used to that explained in the previous report. The conclusions are : -(1) The numerical results of the analytical solution coincide very well with those of digital simulation. (2) Coulomb friction coexisting with the viscous damping in the main system, with a dynamic vibration absorber tuned so as to suppress the resonant response of the system in considering only viscous damping, reduces the maximum amplitudes of the main mass. The features of two equi-height maximums in the resonance curve vanish. (3) Since conventional expressions for the optimum tuning of the absorber do not fit in this case, other new empirical formulae are recommended.
Patent•
06 Aug 1986
TL;DR: In this article, a dynamic vibration absorbing layer composed of spring material or a soft foam layer and a mass or a restriction layer jointing to the outer face of said foam layer onto the surface of the drum section of compressor is applied through adhesive on the body case of compressor.
Abstract: PURPOSE:To lower vibration and noise of compressor by applying a dynamic vibration absorbing layer composed of spring material or a soft foam layer and mass or a restriction layer jointing to the outer face of said foam layer onto the surface of the drum section of compressor. CONSTITUTION:Dynamic vibration absorbing layer 4 is applied through adhesive onto the surface of the drum section 1A or the body case of compressor 1. Said layer 4 is composed of spring material or soft foam layer 5 and a mass or a restriction layer 6 at the outer face. Consequently, the vibration and noise to be produced under operation of compressor 1 can be reduced by the dynamic vibration absorbing function of the spring system constituted with the resiliency of the soft foam layer 5 and the jointing mass (restriction layer) 6. In other words, dynamic vibration absorbing function can be achieved through resonance of the restriction layer (mass) 6 near the inherent vibration to be determined from said mass and the spring constant of the soft foam layer (spring) 5.
TL;DR: In this article, the forced nonlinear vibrations of simple beams supported with two kinds of ball screw type dampers are discussed both numerically and experimentally, and the results may be summarized as follows: (1) Two types of dampers were effective for suppressing the amplitude of the beam at the point of attachment of the damper at the first resonance.
Abstract: The forced nonlinear vibrations of simple beams supported with two kinds of ball screw type dampers are discussed both numerically and experimentally. The dampers are composed of a ball screw, a flywheel and flyball or perpendicular type governor, and they possess nonlinear characteristics. The beam is replaced by a lumped mass system and the Continuous System Simulation Language is used to simulate the motion of the masses and the damper on a digital computer. The results may be summarized as follows: (1) Two types of dampers are effective for suppressing the amplitude of the beam at the point of attachment of the damper at the first resonance. (2) The linear solution which is obtained by regarding the governor as a flywheel differs from the nonlinear solution in the vicinity of the first resonance frequency of the beam. (3) Each damper approaches the snubber for larger values of moment of inertia J of the flywheel, and acts like a dynamic vibration absorber for smaller values of J.
Patent•
21 Nov 1986
TL;DR: In this paper, the authors proposed a forced type vibratory transporting machine with tensile coil springs and mounted a vibration absorber on the trough, which had the same resonance frequency as the exciting frequency of a centrifugal exciter.
Abstract: PURPOSE:To provide a vibratory transporting machine of forced vibration type, which assures a constant greater amplitude, by supporting each weight with tensile coil springs, and by mounting a vibration absorber on the trough, wherein said absorber shall have the same resonance frequency as the exciting frequency of a centrifugal exciter. CONSTITUTION:A plurality of vibration absorbers 17 are installed at the side 16 of a trough 10 at a certain spacing in such a way as symmetrical to the left and right. Each of said vibration absorbers 17 is supported by tensile coil springs 20, 21, and its longitudinal axis X is inclined with a certain angle to the plumb, wherein the resonance frequency Px in X direction shall be the same as the exciting frequency W of a centrifugal exciter 7 and be sufficiently greater than the resonance frequency Py is y direction. Thereby vibrations in the X direction can substantially be absorbed perfectly to allow the trough 10 to vibrate only in the y direction. Thus a forced type vibratory transporting machine is obtained, which assures a constant amplitude with a greater magnitude regardless of varying load.
Patent•
BMW1
TL;DR: In this paper, a motor-vehicle gearbox is described in which the torsional vibrations, in particular those of the output shaft (4), are damped by a vibration absorber.
Abstract: A description is given of a motor-vehicle gearbox in which the torsional vibrations, in particular those of the output shaft (4), are damped. The vibration absorber is designed as an integral component with an output flange (3) secured on the output shaft (4).