Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D11/00—Component parts of measuring arrangements not specially adapted for a specific variable
  • G01D11/10—Elements for damping the movement of parts
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
  • F16F15/00—Suppression of vibrations in systems; Means or arrangements for avoiding or reducing out-of-balance forces, e.g. due to motion
  • F16F15/02—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems
  • F16F15/04—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means
  • F16F15/08—Suppression of vibrations of non-rotating, e.g. reciprocating systems; Suppression of vibrations of rotating systems by use of members not moving with the rotating systems using elastic means with rubber springs ; with springs made of rubber and metal
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
  • G01P1/00—Details of instruments
  • G01P1/003—Details of instruments used for damping
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
  • G01P1/00—Details of instruments
  • G01P1/02—Housings
  • G01P1/023—Housings for acceleration measuring devices

Definitions

• the present invention is related to a vibration damping assembly, preferably for an inertia measurement unit (IMU), according to the pre-characterizing portion of claim 1.
• IMU inertia measurement unit
• the invention origins from the problem to damp vibrations by means of an assembly, preferably for an IMU.
• This unit is a device measuring accelerations (vibrations), vibrations at frequencies beyond the frequencies of interest has to be filtered through electrical filtering as well as through mechanical damping.
• the frequency range for measuring accelerations is very important. Frequencies beyond the frequencies of interest has to be filtered out in a well defined way.
• the filtering characteristics is determined by the functional requirements, the IMU itself and by the environment where it is mounted. When the environmental conditions changes the filtering characteristics has to be changed as well, which with existing technology is complicated and expensive.
• a vibration damping assembly for an IMU is disclosed in WO 00/39526 and comprises two accelerometric sensors containing a mechanically activated gyro laser unit having the shape of a rigid cylindrical sleeve.
• the assembly further comprises two flexible annular membranes which are used as suspension instead of usual shock studs. This assembly is very complex to its construction.
• US 4,811,602 and US 4,848,156 disclose both an apparatus including a parallelogram frame with two accelerometer support surfaces on which two accelerometers are mounted. This apparatus is also very complex to its construction.
• the parallelogram frame is substantially cubic to its form and comprises two flex members each provided with flexures.
• the drive mechanism is provided to vibrate the accelerometers.
• tuning straps are provided at the accelerometers in relation to a base plate.
• An object with the present invention is to provide a vibration damping assembly, preferably for an inertia measurement unit (IMU), in which acceleration can be detected with accuracy and which is simple and reliable to its construction.
• IMU inertia measurement unit
• the invention could be applied in any application where unwanted vibrations have to be filtered out in a well defined way.
• the frequency range by measuring accelerations is very important. Therefore, the filtering characteristics are determined by the functional requirements, the unit itself and by the environment where it is mounted. When the environmental conditions changes the filtering characteristics have to be changed.
• the assembly according to the invention offers a flexible and tunable vibration damping system.
• the housing is mechanically connected to a mounting frame through a number of rubber rods. These rods are mounted in an angle of about 45°. This gives a very flexible tunable system as the number of rods, rod diameter, rod length, rod stiffness and also mounting angle can be changed.
• Fig. 1 is a perspective view of a vibration damping assembly according to the invention.
• Fig. 2 is a side view of the vibration damping assembly in Fig. 1.
• Fig.3 is a view from above of the vibration damping assembly in Fig. 1. it in turned 90° in relation to Fig. 1.
• Fig. 4 is a side view of the vibration damping assembly according to the invention turned 90° in relation to Fig. 2 and is further showing a detail in cross section.
• a vibration damping assembly 1 is shown in Figs. 1 - 4, comprising a housing 2, a mounting frame 3 and resilient rods 4, one end of each rod 4 being fixed to the mounting frame 3 and the other end to the housing 2.
• a trough-shaped recess 5 is provided at each four corners of the substantially rectangular mounting frame 3 so that a mounting flange 6 protrudes at each corner of the mounting frame 3, the bottom surface of the mounting flange being parallel to the bottom surface of the rest of the mounting frame.
• a hole 7 is provided to receive a bolt (not shown) to fasten the vibration damping assembly at a body (not shown) to be measured.
• a panel socket is shown for a data cable assembly (not shown) which is connected to a CPU unit (not shown) for handling data received from the unit.
• the sides 9 of the housing faced to the mounting frame 3 is provided with a collar 10 protruding out from the housing and extending around its circumference.
• the collar 10 is provided with a through recess 11.
• the four through recess 11 are situated flush with the four trough-shaped recesses 5 at the comers of the mounting frame 3, thereby simplifying mounting of the assembly.
• Each upper side 12 of the collar 9 along the circumference of the housing 2 is substantially parallel with the upper surface 13 of the housing 2, and an opposite surface 14 of said collar 10 is chamfered so that it inclines from a line 15 near the outer edge of the side 12 towards the body of the housing 2 providing a cut edge 16 at the outer periphery of the collar 10.
• the mounting frame 3 has a corresponding chamfered surface 17 with substantially the same inclination as and facing the chamfered surface 14.
• the outer and upper edges of the frame are also cut at 18.
• the inner and lower end of the chamfered surface 17 of the mounting frame 3 is substantially vertical, whereby forming a rectangular recess 19 receiving the bottom part 20 of the housing 2.
• a shoulder 22 is formed at the lower and inner edge 21 of the inclined side 11 of the collar 8 so that a gap 23 is provided between the housing and the collar which gap admits a movement between the housing 2 and the frame 3 and thereby prevents contact between these portions of the assembly at operation.
• the resilient rods 4 connecting the housing 2 and the mounting frame 3 with each other are elongated circular cylindrical rods which are fixed at one end in holes 24 distributed around the periphery of the mounting frame 3.
• three through holes 24 are provided at the centre of each side of the mounting frame 3 and two additional through holes 24a are provided near the ends of the outer side 25 of the mounting frame 3.
• five resilient rods 4 are fixed in corresponding holes 24, 24a on each side 25 of the mounting frame 3.
• the other ends of the rods 4 are fixed in corresponding blind holes 26 in the housing 2.
• the holes 24, 24a and 26 in the mounting frame 3 and the housing 2, respectively, are inclined so that the rods 4 will be situated substantially perpendicular to the inclined surfaces 14 and 17 and form an angle of about 45° with the main plane of the upper side 13 of the housing 2.
• the rods are introduced into the holes 24, 24a into the openings thereof on the outer sides 25 of the mounting frame 3 and are thereafter pushed further into the openings of the blind holes 26 in the collar 10 of the housing 2.
• a gap 27 is provided between the collar of the housing and the mounting flange, said gap being so dimensioned that it admits a movement between the housing 2 and the frame 3 and thereby prevents contact between these portions of the assembly at operation.
• the openings of the holes 24, 24a and 26 facing each other in the gap 27 between the housing 2 and the mounting frame 3 are furnished with countersinks 28 and 29, respectively, to minimize the wear of the rods 4 at operation.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Physics & Mathematics (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Acoustics & Sound (AREA)
• Aviation & Aerospace Engineering (AREA)
• Mechanical Engineering (AREA)
• Vibration Prevention Devices (AREA)

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• 2005
  • 2005-06-15 EP EP05752522A patent/EP1896802A1/de not_active Withdrawn
  • 2005-06-15 WO PCT/SE2005/000910 patent/WO2006135283A1/en active Application Filing

Non-Patent Citations (1)

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