JP4807971B2 - Exciter and test method - Google Patents

Description

  The present invention relates to a vibration test apparatus and a vibration test.

  Vibration tests and equipment for such tests are well known in the prior art. The purpose of such a test is to ensure that the product operates normally in any vibration environment that would be experienced in normal use, so that the product can be encountered during transport to its final destination. It varies from simply confirming that it is not damaged by the sexual vibration level. Thus, in some cases, a product to be tested, such as a mechanical, electromechanical, or electronic product, may be operated and tested, while in other cases, such as for purposes of example testing of home appliances. Are tested when the product is not in operation, and of course in other cases the machine assembly has no moving parts, but is still minimal for shipping and / or vibration environments where the product is used May have to meet the vibration capability requirements. Of course, in the end, the dimensions of products so tested can range from very small to very large, and some are equal to or above the temperature range that you expect to experience in shipping and / or use. It is preferable to carry out over such an appropriate temperature range.

  Conventional shakers typically have a rigidly mounted housing with relatively large permanent magnets therein. Usually, a plate-shaped exciter base protrudes above the housing, and this base has a voice coil type electromagnetic drive section extending downward into the air gap of the magnetic circuit, and the vibration table and voice coil. The assembly is preferably mounted on a bending member so that it can vibrate relative to the housing, with minimal rotation about an axis perpendicular to the vibration axis. Accordingly, such an exciter is functionally the same as a voice coil exciter, although the scale and rigidity are completely different.

  Such conventional shakers work well when used properly, but usually have several characteristics that limit their application and the efficiency of their use. For example, such an exciter is a device that is not normally sealed in order to further facilitate the cooling of the voice coil. For this reason, dust and moisture accumulate and their use is limited when used in a test over a certain temperature range, in an uncontrolled environment or especially at low temperatures. Similarly, many commodities to be tested, such as home appliances such as refrigerators, are too large to be secured to a vibration table, even considering a large vibrator. In particular, conventional shaker armature support systems limit the size of the specimen and / or increase the complexity of the test fixture required for larger or heavier specimens. Conventional exciter supports are made as rigid as possible in the lateral direction, but their lateral stiffness does not adversely affect the required axial vibration force and for low frequency testing. In order to provide an appropriate amplitude for the vibration of the armature, it is limited by the need to reduce the armature support stiffness in the axial (normal vibration axis) direction. During excitation of a normal axial vibration test, the eccentric load or asymmetrical rigid part of the specimen will necessarily cause some lateral or rotational vibration motion. Since the tolerances associated with the voice coil are so narrow, these laterally vibrating parts contact the mechanical components inside the shaker and cause damage to the shaker. This situation often places severe limitations on the size and weight of specimens that can be tested on a given shaker. Very often, the size of the shaker must be increased to simply accommodate large or heavy specimens, even when the required vibration force is low.

  For the shaker of the present invention, since the test load is not attached to the moving element, it cannot cause relative lateral movement between the armature and the coil. Therefore, the above problem is eliminated with the vibrator of the present invention.

  Several prior art shakers have been designed in an attempt to overcome some of these limitations. As an example, shakers are known that seal to make them more suitable for use in uncontrolled environments. However, none of these shakers have the combination of features of the present invention.

  The present invention provides a sealed, liquid cooled exciter having a housing to which vibrational forces are coupled, rather than having a conventional exciter table for placing the item to be tested. That is, one or more such shaker housings, each of which may be substantially smaller than the item to be tested, are connected directly to the item to be tested, or alternatively the item to be tested is It can be connected singularly or plurally to the appropriate table or table to be joined. As an example, referring to FIG. 1, a table 10 supported by a coil spring 12 on a suitable support surface 14 is schematically shown. Here, a plurality of, in this particular embodiment four, shakers 16 (see also FIG. 2) are used to apply a vibration force to the table 10 and thus to the object 18 to be tested. Since each shaker generates significant vibration forces for its dimensions, and large objects are often tested only at relatively low G levels, an appropriate number to provide the desired total vibration force. By using this shaker, the object to be tested may be considerably larger than the shaker itself. Moreover, since the vibration forces of the plurality of shakers are distributed around a certain area, the table 10 is as rigid as would be required if less vibration force distribution would be used. There is no need. In general, such a table is made from aluminum, usually with a portion cut away to reduce weight without sacrificing much stiffness. However, other lightweight materials can be preferably used depending on the application.

  Referring now to FIGS. 3 and 4, there can be seen a cross-sectional view and an exploded cross-sectional view of an exemplary embodiment of a vibrator according to the present invention. In the shaker of the present invention, two voice coils 20, 22 are coupled to the inner periphery of the central housing member. The top and bottom of the housing are surrounded by top and bottom housing caps 26, 28 that are bolted to the central housing member 24 by bolts 30. In addition, the at least one top and bottom housing cap has a plurality of threaded screw holes 32 therein (see also FIGS. 6 and 7), which can be on a table as shown in FIGS. Maybe it can be used to bolt the shaker directly to the product or commodity to be tested. On the other hand, only one screw hole 32 is shown in the picture of FIG. 3, and four such holes are shown in FIG. 7, but of course any number and / or pattern can be used as desired. Can be used. Bolting in this manner to the shaker table or the object to be tested is preferred because of the potential stiffness of the attachment, but additional attachment means can also be used.

  There is a bent member 34 captured between the top housing cap 26 and the central housing member 24, a front view of which can be seen in FIG. A similar bending member 36 is captured around its outer periphery between the lower housing cap 28 and the central housing member 24 and has an O-ring seal 38 that prevents moisture from entering the shaker housing. is doing. Top housing cap 26 and lower housing cap 28 have central removable plugs 40, 42 with O-rings 44 that seal this portion of the shaker housing. As will be seen later, the central removable plugs 40, 42 are provided for alignment purposes during assembly of the shaker, and if for some reason the shaker is not disassembled at a later date, otherwise Is usually not removed afterwards.

  Bending members 34, 36 support a magnet assembly comprising axially magnetized permanent magnet 46, magnetic pole 48, short ring 60, and cooling coil 62 (perpendicular to the orientation shown in FIGS. 3 and 4). As is known in the art, a shorting ring, preferably copper, which is usually a good conductor, reduces the drive coil inductance at higher frequencies and allows vibration testing at higher frequencies. Sometimes, it is possible to sufficiently excite the drive coil without requiring a very high drive voltage. In assembly, the short ring 60 is epoxy bonded or soldered to the magnetic pole 48 and the cooling coil 62 is bonded to the short ring. The magnetic poles are then epoxy bonded to the magnets in a properly fixed state to obtain a permanent coaxial and concentric arrangement of the magnets and magnetic poles. Each pole 48 has an integral coaxial and concentric cylindrical projection 50 that leveles the magnet assembly with the central housing member 24. Each pole also has a concentric threaded central hole for receiving a bolt 52 having a cylindrical handle 54 that slides within a snug hole in the protrusion 50 and cap 56. In order for the various parts of the permanent magnet assembly to be concentric, and for the various parts to be accurately positioned with respect to each other, the permanent magnet assembly is placed on the upper side before the plugs 40, 42 are in place. And appropriate alignment fixtures extending through the openings in the lower housing caps 26, 28 can be centered within the housing during assembly. With such a fixture, concentricity with the housing of the entire magnet assembly is determined by determining such concentricity of the cap 56 prior to tightening the bolt 52. The central hole 58 (see FIG. 5) of each bending member is slightly larger than the diameter of the handle of the bolt 52 so that a desired concentricity can be established while the bending member is not bent at least in the radial direction. Made intentionally.

  The present invention supplies high vibration force to the size of the shaker and is suitable for use in harmful environments (dust, dirt, moisture, etc.) and extreme temperature environments (both high and low temperatures) It is for making things. When generating high vibration forces, the high current in the drive coils 20, 22 causes significant power dissipation in the coils due to the resistance of the coils, thereby heating the central housing member 24. Eddy currents in the shorting ring 60 on the permanent magnet assembly also cause significant energy loss and heat generation, especially at higher frequencies. These regions of the present exciter are cooled by the liquid pumped through the coil 62 on the shorting ring and the coil 66 on the periphery of the central housing member 24. Although the coil 66 is on the outer periphery of the central housing member 24, in a preferred embodiment, the end 68 of the coil 66 extends through the upper and lower sections of the central housing member 24 and is sealed and applied to them. Connected to the internal end of the standard pipe joint 70 in the vibrator. Similarly, the end 72 of the coil 62 (one continuous tube) extends through the hole in the magnetic pole 48 and is connected to the pipe joint 70 via the flexible tube 74. Thus, the tube forming coil 66 and the tube forming coil 62 are connected in parallel to the pipe joint 70 and, as a result, cooled to both via the pipe joint 70 firmly attached to the sides of the top and bottom caps 26, 28. A fluid flow is provided.

  In the illustrated embodiment, the shorting ring 60 has a thin area bonded around the pole 48. This is primarily for convenience of installation, and other forms and locations of attachment can be used. Similarly, although the shorting ring is adjacent to the coil secured inside the central housing member 24, they are not entirely central on the coil. However, it is symmetric without center alignment, so the coupling from the coil to the shorting ring is substantially constant throughout the stroke of the permanent magnet assembly.

  The cooling fluid used may be water, a mixture of water and an antifreeze such as ethylene glycol, oil, or other fluid, if desired, and the cooling fluid is typically cooled before being recycled through the shaker. The ability to cool the shaker in the area of the energy dissipating parts of the shaker is not always necessary, but prevents overheating of the shaker components, especially when testing at high temperatures and high power levels Give ability. It is also effective in preventing the heat generated by the shaker from disturbing the temperature of the test environment in some cases when testing at lower temperatures. Thus, for example, for low temperature testing, the exciter can be removed to substantially remove all heat generated by the operation of the shaker so that the shaker has virtually no net effect on the test environment. Controlled circulation of even lower temperature fluids can be used for cooling. Similarly, if it is desired that the shaker be stable at the test environment temperature, prior to the shaker operation, to reduce the time required for the shaker itself to reach the test environment temperature. It is useful to supply a cooling liquid to heat or cool the shaker. In particular, even a moderately sized permanent magnet assembly in a shaker according to the present invention has a considerable heat capacity, and only a relatively weak heat flow path to the outside world, except that a cooling coil 62 is provided. I don't have it. As a result, without the ability to cool or heat the magnet assembly, the thermal time constant of the magnet assembly to directly predetermine its temperature can be very long. Similarly, higher energy permanent magnet materials lose magnetism at high temperatures and may even become permanently demagnetized when exposed to sufficiently high temperatures. The liquid cooling coil placed on the exciter short circuit turn of the present invention also serves to cool the magnet via the end poles. This not only protects against the loss of force with increasing temperature, but also ensures that there is no catastrophic event of permanent magnet demagnetization.

  In the preferred embodiment disclosed herein, the cooling coils for the housing and magnet assembly are connected in parallel, so that only two fluid connections are used. Alternatively, however, the two sets of cooling coils can each have their own fluid connection. This allows the shaker to operate with the permanent magnet assembly and the shaker housing at different temperatures. As an example, at high test temperatures due to thermal contact between the shaker and the table (or test object) to which the shaker is fixed, and between the table and the test object. Apart from that, it may be necessary or desirable to allow the shaker housing to reach the test temperature and operate to keep the permanent magnet assembly at a lower temperature. This avoids temperature gradients in the test object and at the same time protects the permanent magnet from exposure to high temperatures.

  The shaker according to the present invention can be manufactured in a wide range of dimensions, but the ability to supply a high vibration force for a given size of the shaker is any one shaker. Together with the ability to use multiple shakers to vibrate a much larger test table, it allows large objects to be tested with a much smaller shaker. This should be compared to a conventional shaker with a fixed housing and vibration table that would require a large mass shaker to test the same size object. is there.

  The shaker of the present invention has a combination of features that make it suitable for use in many applications. As an example, in a conventional voice coil shaker having a shaker housing and a voice coil / table assembly mounted for vibration along the axis of a permanent magnet, the object to be vibration tested is usually a table. Clamped or bolted to This increases both the support mass increase and the moment of inertia of the support mass about an axis perpendicular to the axis of the shaker housing. As a result, rotation of the support mass around an axis perpendicular to the exciter housing with a relatively low natural frequency of the support device due to the high moment of inertia of the total support mass due to the eccentric load on the shaker table Is induced. As a result, the voice coil exciter is particularly sensitive to eccentric loads and can be permanently damaged by the eccentric load when the voice coil rubs the permanent magnet pole or housing. However, in the present invention, the supporting mass and its moment of inertia are constant and are not affected by the moment of inertia of the object being tested. Therefore, the shaker of the present invention is much more resistant to eccentric specimens. This is combined with the fact that the shaker of the present invention is sealed, without being adversely affected by dirt and moisture, and because there is cooling, especially without overheating of the permanent magnet. Without being able to operate at high power and / or at high temperatures for a long time, it is well suited for use in hazardous environments such as in an environmental chamber on a production line. It should be noted that the overall symmetry of the preferred embodiment exciter with a circular housing body with the same end cap, a symmetrical double-headed permanent magnet assembly, and a bent support diaphragm provides high vibration force and reduction. Resulting in both manufacturing costs.

  For tests such as a production line test of a manufactured assembly, such tests are typically performed at a relatively low G value. In order to facilitate the quick coupling of the vibration table 10 (see FIG. 8) to the item 18 to be vibration tested, the retainer 100 attached to the spring is connected to the table 10 with the item 18 to be tested during the test. Can be lowered to hold. Although a simple flat plate-like cage 100 is shown in FIG. 8, the cage and table 10 can be shaped to mimic the support of an item when packaged for shipping. it can. As an example, some items are shipped in a larger box and are supported by foamed corner support members inside the box. The table 10 and the cage 100 can be simply configured to support the item in substantially the same way during the vibration test. The coupling of such a vibration table and the item to be tested can be much faster than using clamps or bolts, while at the same time representing the actual shipping support and vibration environment much better. The retainer 100 can also have one or more shakers 12 that are secured to the retainer as shown in FIG. 8 if additional excitation forces are required.

  Similarly, the shaker of the present invention is sealed and can be fluid cooled, so the shaker 16 and shaker table 10 can actually be placed in the test chamber 102 (see FIG. 9). ). Such chambers can be sealed for testing at various pressures other than atmospheric pressure and / or insulated for testing at various temperatures other than ambient temperature. This uses a prior art shaker where the item to be tested, fixed to the shaker table, protrudes through the open bottom of the test chamber, rather than being in the test chamber. Compare with temperature test. As a result, if a large temperature gradient usually occurs reliably and must be tested at different pressures, the pressure chamber itself may need to be attached to the shaker table and vibrated with the item to be tested. .

  As shown in FIG. 9, a typical test chamber using the present invention includes a shaker table 10, a corresponding attachment 12, a shaker 16 fixed to the shaker table, and an item 18 to be tested. Are all in the test chamber. In addition to the normal shaker controller provided in the shaker 16, a shaker temperature controller that circulates the fluid through the cooling coil of the shaker 16 can be provided. Particularly in high temperature testing, it may be desirable or necessary to actually cool the shaker 16 to a temperature substantially lower than the temperature set for the test chamber. For this purpose, the shaker 16 can have thermal insulation 104 provided around them and can also be insulated from the table 10 by a layer of rigid thermal insulation. The chamber 102 can also have heating or cooling or both chamber temperature control, and can be appropriately sealed for pressure control if desired.

  Referring now to FIG. 10, another implementation of the present invention can be seen. Here, the two shakers 16 are bolted using a mounting ring 106 coaxially with each other or end to end. In many cases it will be preferable to distribute the vibrational force over a larger area as shown in FIGS. 1 and 2, but a pair (or more) of exciters to vibrate heavy concentrated items Can be combined as shown in FIG. 10 and / or can be used in a distributed manner (see FIGS. 1 and 2) in which multiple pairs are connected in this way.

  While several preferred embodiments of the present invention have been disclosed and described herein, those skilled in the art can make various changes in form and detail without departing from the spirit and scope of the invention. It will be understood that it can be done. Similarly, various aspects of the invention can be advantageously implemented by incorporating all features or various sub-combinations of features.

It is a schematic side view of the vibrator and shaker table by this invention. It is a schematic top view of the shaker and shaker table by this invention. It is a sectional side view of the vibration exciter by this invention. It is an exploded view of the vibration exciter of FIG. It is a front view of the bending member used for the vibrator by FIG. FIG. 5 is a first (inside) front view of a shaker housing cap used in the shaker according to FIGS. 3 and 4. FIG. 5 is a second (outside) front view of a shaker housing cap used in the shaker according to FIGS. 3 and 4. It is a figure which shows another method of connecting the goods which should be tested to a shaker table. FIG. 3 is a diagram showing the use of the shaker and the shaker table as a whole in the environmental chamber. It is the figure which connected two shakers together.

Explanation of symbols

  10 Table, 12 Coil spring, 14 Support surface, 16 Exciter, 18 Test object, 20, 22 Voice coil, 24 Central housing member, 26 Top housing cap, 28 Bottom housing cap, 34, 36 Bending member, 40, 42 Removable plug, 46 Permanent magnet, 48 magnetic pole, 60 Short ring, 62, 68 Cooling coil, 100 Cage

Claims (31)

A sealed exciter housing;
A permanent magnet assembly supported in the housing for causing an oscillating translational movement along its axis, wherein the permanent magnet is magnetized parallel to the axis, the first and second of the permanent magnets. A permanent magnet assembly having first and second magnetic poles spaced apart along said axis at the ends of
First and second wire coils respectively adjacent to the first and second magnetic poles and spaced from the periphery thereof to the outside and fixed to the inner wall of the shaker housing;
A first fixed to the permanent magnet assembly and flexibly connected to a tube connection on the shaker housing through which fluid can circulate to heat or cool the permanent magnet assembly A tubular coil of
A second fixed to the shaker housing and connected to a tube connection on the shaker housing through which fluid can circulate to heat or cool the permanent magnet assembly. A tubular coil;
Have
The permanent magnet assembly has at least one conductive shorting ring supported on the permanent magnet assembly adjacent to the at least one wire coil;
A shaker adapted to couple the shaker housing to a shaker table or an item to be tested.   The vibration exciter according to claim 1, wherein the first tubular coil and the second tubular coil are connected in parallel.   The said at least one conductive shorting ring is comprised of first and second shorting rings, each supported on a permanent magnet assembly adjacent to each one of said wire coils. Shaker.   The said 1st tubular coil is provided with the 1st, 2nd 1st tubular coil part connected in series, and each is each couple | bonded with one each of the said 1st, 2nd short circuit ring. Shaker.   The vibrator according to claim 4, wherein the first and second first tubular coil portions are formed of a single length tube.   The vibrator according to claim 1, wherein the second tubular coil is fixed to an outer periphery of the housing adjacent to the wire coil.   The vibration exciter according to claim 1, wherein the permanent magnet assembly is supported in the housing by a bent epoxy resin graphite laminated diaphragm.   2. A vibrator according to claim 1, wherein opposing faces of the shaker housing are adapted to couple to a shaker table or an item to be tested.   The fixture further comprised so that it might fix to the 2nd fixture fixed to the one surface of the said shaker, and the 2nd fixture fixed to the exact same shaker. The described shaker.   The first and second shakers according to claim 9, wherein the first and second shakers are fixed to each other coaxially with the shaft of the permanent magnet assembly. A circular housing body defining a shaker shaft, and a sealed shaker housing having first and second end caps;
A cylindrical permanent magnet that is magnetized in a direction parallel to the shaker shaft, and a first that contacts the first and second ends of the permanent magnet that are arranged at intervals along the shaker shaft. A permanent magnet assembly having a second magnetic pole and supported within the housing for oscillating translational movement along the shaker axis;
First and second wire coils respectively adjacent to the first and second magnetic poles and spaced from the periphery thereof to the outside and fixed to the inner wall of the shaker housing;
A first fixed to the permanent magnet assembly and flexibly connected to a tube connection on the shaker housing through which fluid can circulate to heat or cool the permanent magnet assembly A tubular coil of
A second fixed to the shaker housing and connected to a tube connection on the shaker housing through which fluid can circulate to heat or cool the permanent magnet assembly. A tubular coil;
The permanent magnet assembly has at least one conductive shorting ring supported on the permanent magnet assembly adjacent to the at least one wire coil;
A shaker adapted to couple the shaker housing to a shaker table or an item to be tested.   The vibrator according to claim 11, wherein the first tubular coil and the second tubular coil are connected in parallel.   12. The first and second shorting rings of claim 11, wherein the at least one conductive shorting ring is comprised of first and second shorting rings, each supported on a permanent magnet assembly adjacent to each one of the wire coils. Shaker.   14. The first tubular coil portion comprises first and second first tubular coil portions connected in series, each coupled to a respective one of the first and second shorting rings. Shaker.   15. The vibrator according to claim 14, wherein the first and second first tubular coil portions are formed from a single length tube.   The vibrator according to claim 11, wherein the second tubular coil is fixed to an outer periphery of the housing adjacent to the wire coil.   The vibration exciter according to claim 11, wherein the permanent magnet assembly is supported by a bent epoxy resin graphite laminated diaphragm in the housing. 12. A shaker according to claim 11, wherein the first and second end caps of the shaker housing are adapted to couple to a shaker table or an item to be tested.   19. A fixture further configured to be secured to one face of the shaker housing and to be secured to a second fixture secured to an identical shaker. The vibrator according to 1.   20. The first and second shakers according to claim 19, wherein the first and second shakers are fixed to each other coaxially with the shaft of the permanent magnet assembly. A method of vibration testing using one or more vibrators as claimed in claim 1, comprising:
Securing the one or more shakers to an item to be vibration tested or a table supporting the item ;
Operating the one or more shakers to vibration test the item to be tested.   The method of claim 21, further comprising fluid cooling the shaker. When one or more shakers are fixed to the table,
The method of claim 21, wherein the item to be vibration tested is secured to the table. When one or more shakers are fixed to the table,
The method of claim 21, wherein the item to be vibration tested is placed on a second surface opposite the first surface of the table to which the one or more shakers are secured . When one or more shakers are fixed to the table,
The method of claim 21, wherein one or more shakers are secured to the first surface of the table. When multiple shakers are fixed to the table,
26. The method of claim 25, wherein the plurality of shakers are distributed in a pattern across the first surface of the table. When one or more shakers are fixed to the table,
Place the table to which the one or more shakers are fixed in a sealed environmental chamber, control the interior of the chamber to a pressure different from atmospheric pressure, and test the item to be tested at the chamber pressure The method of claim 21, further comprising: 28. The method of claim 27 , further comprising changing the temperature in the environmental chamber and testing the item to be tested at the chamber temperature.   30. The method of claim 28, further comprising insulating and fluid cooling the one or more shakers. When one or more shakers are fixed to the table,
The table to which the one or more shakers are fixed is placed inside an environmental chamber, the temperature in the chamber is controlled to be different from atmospheric pressure, and the item to be tested vibrates at the chamber temperature. The method of claim 21, further comprising testing. 32. The method of claim 30 , further comprising insulating and fluid cooling the one or more shakers.

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