US3670216A - Voltage variable resistors - Google Patents

Voltage variable resistors Download PDF

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Publication number
US3670216A
US3670216A US10959A US3670216DA US3670216A US 3670216 A US3670216 A US 3670216A US 10959 A US10959 A US 10959A US 3670216D A US3670216D A US 3670216DA US 3670216 A US3670216 A US 3670216A
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US
United States
Prior art keywords
percent
oxide
muffler
silver
voltage variable
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US10959A
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English (en)
Inventor
Takeshi Masuyama
Toshioki Amemiya
Yoshio Iida
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP44014792A external-priority patent/JPS492716B1/ja
Priority claimed from JP44018238A external-priority patent/JPS492717B1/ja
Priority claimed from JP44065500A external-priority patent/JPS4840794B1/ja
Priority claimed from JP44065501A external-priority patent/JPS4840795B1/ja
Priority claimed from JP44065502A external-priority patent/JPS4840796B1/ja
Priority claimed from JP44065498A external-priority patent/JPS4840792B1/ja
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Application granted granted Critical
Publication of US3670216A publication Critical patent/US3670216A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C7/00—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material
    • H01C7/10—Non-adjustable resistors formed as one or more layers or coatings; Non-adjustable resistors made from powdered conducting material or powdered semi-conducting material with or without insulating material voltage responsive, i.e. varistors
    • H01C7/105—Varistor cores
    • H01C7/108—Metal oxide
    • H01C7/112—ZnO type

Definitions

  • the voltage variable resistor modified with 317/235 AQ lanthanum oxide (Lagoa) and/or yttrium oxide (Y O has the [51] Int. Cl ..l-l01l 3/22 electrical properties thereof improved by the further addition [58] Field of Search ..317/238, 235 AP, 235 AQ of cobalt oxide (C00) and manganese oxide (MnO).
  • the present invention relates to muffler constructions and has particular reference to a muffler which is specifically designedforuse injconnection with the-internal combustion engine of a model airplane, especially competition type model airplanes which are radio controlled from the ground.
  • the invention is concerned with an expansion type mufiler or exhaust silencer which, when operatively installed on a model airplane engine andthe airplane is in flight, is disposed directly in the slipstream of the airplane propeller and depends upon well known phenomena associated with airfoil design for its successful operation.
  • the improved model airplane mufiler is of symmetrical airfoil design, which is to say that both .the upper and lower sides thereof are arched in airfoil fashion and, in effect, constitute a tubularstructure which is of tear drop design in transverse cross section.
  • This tubular structure is closed at its opposite ends by means of tear drop shaped endwalls, thus defining an internal, maximum volume, full length, full heightand fullwidth expansion 5 chamber.
  • the muffler is so designed and-installed on a model airplane engine that it projectsradially outwardly from the en'- gine cylinder and the exhaust gases leaving the engine cylinder enter thej'expansion chamber through the inner end wall and are expanded inthe chamben'These expanded gases leave the expansion chamber through a series of outletports which are formed in the camber regions of the muffler at locations'where theyare in direct register with the vacuum areas above and below the muffler. . These vacuum areas, acting through the outlet ports'assist in drawing the. expanded gases from the chamber and, in so doing, they not only decrease the noise level involved due to gas evacuation, but also reduce the'back pressure on the engine to aCDC'gedegree.
  • weight consisting as itdoes of three light gauge stainless steel sheet metal pieces cut to shape and silver soldered together along certain meeting edges.
  • a further and important object of the invention is to provide a mufiler which is possessed of a high heabdissipating factor, such object being attained by the use of the aforementioned stainless sheet material for the muffler walls. With such high heat-dissipating qualities for the muffler as a whole, a cool running engine will be the obvious result.
  • Yet another object is to provide a novel muffler mounting including an angular muffler manifold by means of which the muffler proper may be cause to assume an out-of-the-way position when it is applied to a side mounted engine.
  • FIG. 2 is a front perspective view of the structure shown in FIG. 3 is a fragmentary top plan view of the inner the mufller and its adapter and clamping assembly;
  • FIG. 4 is an' end elevational view of the structure shown in FIG. 3, the adapter strap being broken away in the interests of clarity; i
  • FIG. 5 is a front inside mufflerperse
  • FIG. 6 is a rear outside top perspective view of the mufiler
  • FIG. 7 is a top plan view of the mufiler
  • FIG. 8 is an outside end elevational view of the muffler
  • FIG. 9 is a front mid-plane elevational view of the muffler.
  • FIG. 10 is an outside rear mid-plane perspective view of the muffler
  • FIG. 11 is an exploded perspective view of the muffler and its associated adapter plate and clamping assembly
  • FIG. 12 is a sectional view, entirely schematic in its representation, illustrating certain aerodynamic principles which are involved in connection with the operation of the portion of mid-plane perspective view of the present muffler;
  • FIGS. 1 and 2 a preferredform of model airplane muffler embodying the principles of the present invention is designated in its entirety by the'reference numeral 10 and it is shown as being operatively applied to a conventional model airplane ensame, the present muffler being readily applicable to a wide variety of engine constructions.
  • the engine selected for environmental purposes herein embodies the usual crankcase 16 from which there projects vertically upwardly a cylinder 18.
  • a crankshaft 20 which is rotatable in the crankcase 16 is associated with the usual connecting rod and piston (not shown), the latter being reciprocable in the cylinder 18.
  • the forward'end of the crankshaft threadedly receives thereon a clamping nut and hub assembly 23 by means of which a propeller (not shown) may be fixedly secured to the crankshaft.
  • Other conventional engine components are a cylinder glow plug 22 at the top of the cylinder 18, a carburetor 24 which receives fuel from a fuel line 26, a throttle or fuel adjustment rod 28, and other combustion engine components the details of which have not been disclosed herein.
  • a tubular extension 29 projects laterally from one side of the cylinder 18 in the medial region of the latter and defines an elongated slot-like exhaust port 30 for the combustion gases issuing from the engine.
  • This exhaust port 30 communicates through an adapter block or plate 32 (see also FIGS. 3 and 11) with the muffler 10 in a manner and for a purpose that will be set forth in detail presently.
  • this muffler is in the form of a lightweight hollow stainless steel member of tapered tubular construction and which is closed at its ends.
  • the muffler involves in its general organization a top wall 34, a bottom wall 36, an outer end wall 38 (FIGS. 6, 7, 8 and 10), and an inner end wall 40 (FIGS. 4, and 11).
  • Both the top wall 34 and the bottom wall 36 are of airfoil shape or design, the top wall 36 being arched upwardly with the extreme crest of the arch lying forwardly of the central longitudinal axis of the tubular muffler as indicated by the broken line 42 in FIGS. 6, 7 and 8.
  • the bottom wall 36 is similarly arched downwardly.
  • the muffler is tapered on a small slant angle.
  • the leading side thereof is curved as indicated at 44 in FIGS. 2, 5 and 8 with fairly large increments of cuuvature prevailing, while the trailing side of the muffler presents a relatively sharp and linearly straight knife edge 46.
  • the tubular muffler is of tapered design and, therefore, the inner end wall 40 is appreciably larger than the outer end wall 38, both walls being generally of tear drop configuration in outline.
  • the inner end wall 40 is flat or planar while the outer end wall 38 is preferably, but not necessarily, curved so that it bulges outwardly as clearly shown in FIGS. 6 and 7, the shading of this wall in FIG. 6 representing the bulge. It is however within the purview of the present invention to construct, the muffler so that the outer end wall 38 is planar and generally parallel to the wall 40, in which case the muffler will assume the form of a tapered frustum.
  • the inner end wall 40 is formed with a linearly straight row of muffler inlet ports 49, five such ports being shown herein although a greater or a lesser number of such ports may be employed if desired.
  • These ports 49 lie on the major axis of the tear drop shaped end wall 40 and they are designed for register with the exhaust port 30 (FIG. 2) of the cylinder 18 when the muffler 10 is installed on the engine 12.
  • the outer end wall 38 is imperforate.
  • the top wall 34 of the muffler 10 is fonned with a row of relatively small outlet ports 50, the row extending in the longitudinal direction of the mufiler and being disposed an appreciable distance rearwardly of the aforementioned crest 42 of the arched portion of the top wall 34 so that the ports lie well within the chamber area of the airfoil shaped wall.
  • outlet ports 50 have been disclosed herein, it will be understood that a greater or a lesser number of such ports may be provided if desired.
  • this row of ports is disposed in the outer region of the muffler remote from the inlet ports 49.
  • a similar row of outlet ports 51 is provided in the bottom wall 36 and they are similarly positioned.
  • the adapter plate 32 may be in the form of either a casting or a machined part and it is in the form of an elongated narrow strip of metal,
  • the adapter plate 32 preferably aluminum of approximately square cross section I and having a centrally disposed slot 54 extending transversely therethrough.
  • One side of the adapter plate 32 fits flat against the inner end wall 40 of the muffler 10 when the adapter plate is installed thereon with the slot 54 embracing all of the muffler inlet ports 49 in the end wall 40.
  • the opposite side of the adapter plate 32 is recessed at the rim region of the slot, thus providing a shallow seating or pilot socket into which the outer rim region of the tubular extension 29 projects so that the exhaust port 30 registers with the slot 54, and consequently with the ports 49 in the muffler end wall 40.
  • a U-shaped clamping strap or band 60 (FIGS. 1, 2 and 11) having parallel side legs 62 and a connecting bight portion 64 is provided.
  • the outer ends of the sidev legs 62 are turned laterally outwardly away from each other to provide a pair of attachment ears 66.
  • a pair of clamping screws 68 and 70 project through a pair of holes 72 which are provided in the attachment cars 66, through a pair of bores 74 formed in the end regions of the adapter plate 32, and also through similar holes 75 which are provided in the end wall 40, these screws being threadedly received by nuts 76 (FIG. 3) which are welded to the inside face of the muffler wall 40.
  • the clamping screw 70 also passes through an alignment collar or sleeve 78 which is welded to one of the cars 66.
  • the curvature of the bight portion 64 of the clamping strap 60 is comformable to that of the cylinder 18 of the engine 12 and the strap partially encircles the cylinder at approximately the level of the tubular extension 29 when the strap is in position on the cylinder so that upon tightening of the clamping screws 68 and 70, the muffler 10 is drawn hard against the rim of the tubular extension 29 and the exhaust port 30 communicates with the interior of the muffler through the adapter plate and in sealing relationship. In this position of the muffler 10, the longitudinal axis of the latter extends horizontally and projects radially outwardly from one side of the cylinder 18.
  • the muffler 10 is of extremely lightweight construction, it being constructed in the main of relatively thin stainless steel sheet stock having a thickness on the order of 0.015 inches.
  • the muffler lends itself to ease of manufacture in that the top wall 34 and bottom wall 36 are of unitary onepiece construction and are formed from a single blank of the stainless steel sheet metal. The blank is folded, so to speak, so as to bring the opposite ends thereof together to form the sharp trailing edge 46, after which they may be silver soldered together. Thereafter, the tear drop shaped end walls 38 and 40 are soldered in position to close the ends of .the thus formed tubular symmetrical airfoil structure.
  • the outer end wall 38 is formed of stainless steel sheet material similar to that which forms the top and bottom walls 36 and 38, while the inner end wall 40 is formed of somewhat thicker stainless steel material which may be on the order of 0.035 inches in thickness. It will be understood of course that the various openings 49, 50, 51 and 75 are punched or otherwise fonned in the sheet metal stock prior to assembly of the three constituent parts of the muffler.
  • the thus assembled muffler 10 which is comprised of three sheet metal stampings, produces a symmetrical airfoil shape which defines an internal expansion chamber of maximum volume.
  • the muffler 10 projects radially and horizontally from the TABLE 1 Silver nintA Sil i lzfliqa 2013 (C MnO lam! I mo. Ill). n10. (moi. at (3 :t ZnO (moLperccnt) percent) percent) percent) percent) percent) percent) 100 uni.) 1i 0 1nn.) 1i
  • Example 1 The'lappe d disc is coated on one surface thereof with the same silver electrode paints as those used in'Example l by a conventional brushing method.
  • the coated disc is fired at the temperature listed in Table 2 'for 30 minutes in air.
  • the fired disc is provided on another surface thereof with an ohmic electrode by means of spraying of aluminum or evaporating of aluminum.
  • Lead wires are attached to the silver electrodes by means of silver paint.
  • the electrical characteristics of the resultant-resistor and of other similarly prepared resistors are shown in Table 3, wherein electrical characteristics are measured with a polarity in which the high voltage terminal is the silver electrode.
  • Sintered discs having the compositions listed in Table 4 are prepared in the same manner as that in Example I.
  • the sintered discs are 10 mm in diameter and 1.5 mm in thickness after lapping.
  • Various silver electrode paints are applied to the opposite surfaces of the sintered discs and fired at the temperatures listed in Table 4 for 30 minutes in air.
  • the silver electrode paints have solid ingredient compositions shown in Table 4 and are prepared by mixing 100 weight parts of said solid ingredient compositions with l to 20 weight partsof epoxy resin in 20 to 40 weight parts of butyl alcohol.
  • the resultant resistors exhibit desirable C values and n values as indicated in Table 4. It will be readily understood that the electrode compositions have a great effect on the electrical characteristics of the resultant voltage variable resistors and particularly electrode compositions containing cobalt oxide and manganese oxide result in a higher value of n.
  • EXAMPLE 4 Sintered discs having compositions listed in Table 5 are made into resistors in the same manner as that of Example 1.
  • the resistors are tested according to the methods used in 'testing electronic component parts.
  • the load life test is carried out at C ambient temperature at 1 watt rating power for 500 hours.
  • the heating cycle test is carried out by repeating five times a cycle in which said resistors are cooled to 20 C and then kept at such temperature for 30 minutes. After the 70 heating cycle and load life tests, the percentage change in the C valueand n value are shown in Table 5. It will be easily realized that the percentage changes are less than 10 percent and especially the composition of silver electrodes containing cobalt oxide and manganese oxide result in excellent properties with respect to stability.

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  • Engineering & Computer Science (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermistors And Varistors (AREA)
  • Exhaust Silencers (AREA)
US10959A 1969-02-24 1970-02-12 Voltage variable resistors Expired - Lifetime US3670216A (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP44014792A JPS492716B1 (zh) 1969-02-24 1969-02-24
JP44018238A JPS492717B1 (zh) 1969-03-07 1969-03-07
JP44065500A JPS4840794B1 (zh) 1969-08-15 1969-08-15
JP44065501A JPS4840795B1 (zh) 1969-08-15 1969-08-15
JP44065502A JPS4840796B1 (zh) 1969-08-15 1969-08-15
JP44065498A JPS4840792B1 (zh) 1969-08-15 1969-08-15

Publications (1)

Publication Number Publication Date
US3670216A true US3670216A (en) 1972-06-13

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Application Number Title Priority Date Filing Date
US10959A Expired - Lifetime US3670216A (en) 1969-02-24 1970-02-12 Voltage variable resistors

Country Status (4)

Country Link
US (1) US3670216A (zh)
FR (1) FR2032355B1 (zh)
GB (1) GB1290945A (zh)
NL (1) NL152395B (zh)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4086189A (en) * 1975-11-14 1978-04-25 Otowa Electric Company, Ltd. Resistive element having voltage non-linearity and method of making same
US4160748A (en) * 1977-01-06 1979-07-10 Tdk Electronics Co., Ltd. Non-linear resistor
EP0070468A2 (en) * 1981-07-16 1983-01-26 Kabushiki Kaisha Toshiba Metal Oxide varistor
US4436650A (en) 1982-07-14 1984-03-13 Gte Laboratories Incorporated Low voltage ceramic varistor
US4724511A (en) * 1985-10-24 1988-02-09 Itt Industries, Inc. Dielectric compositions
US5644284A (en) * 1994-04-27 1997-07-01 Matsushita Electric Industrial Co., Ltd. Temperature sensor

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3299332A (en) * 1961-07-10 1967-01-17 Murata Manufacturing Co Semiconductive capacitor and the method of manufacturing the same
US3386856A (en) * 1963-12-13 1968-06-04 Philips Corp Method of making a manganese oxide dielectric coating for barrier-layer capacitors
US3419759A (en) * 1965-09-17 1968-12-31 Matsushita Electric Ind Co Ltd Capacitor comprising ferroelectric ceramic with oxidic silver electrodes and heterojunction barrier layer between electrodes and ceramic
US3503029A (en) * 1968-04-19 1970-03-24 Matsushita Electric Ind Co Ltd Non-linear resistor
US3505574A (en) * 1966-07-08 1970-04-07 Globe Union Inc Ceramic composition for barrier layer capacitors
US3529218A (en) * 1967-07-28 1970-09-15 Matsushita Electric Ind Co Ltd Ceramic rectifier and a method for preparing the same

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3299332A (en) * 1961-07-10 1967-01-17 Murata Manufacturing Co Semiconductive capacitor and the method of manufacturing the same
US3386856A (en) * 1963-12-13 1968-06-04 Philips Corp Method of making a manganese oxide dielectric coating for barrier-layer capacitors
US3419759A (en) * 1965-09-17 1968-12-31 Matsushita Electric Ind Co Ltd Capacitor comprising ferroelectric ceramic with oxidic silver electrodes and heterojunction barrier layer between electrodes and ceramic
US3505574A (en) * 1966-07-08 1970-04-07 Globe Union Inc Ceramic composition for barrier layer capacitors
US3529218A (en) * 1967-07-28 1970-09-15 Matsushita Electric Ind Co Ltd Ceramic rectifier and a method for preparing the same
US3503029A (en) * 1968-04-19 1970-03-24 Matsushita Electric Ind Co Ltd Non-linear resistor

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4086189A (en) * 1975-11-14 1978-04-25 Otowa Electric Company, Ltd. Resistive element having voltage non-linearity and method of making same
US4160748A (en) * 1977-01-06 1979-07-10 Tdk Electronics Co., Ltd. Non-linear resistor
EP0070468A2 (en) * 1981-07-16 1983-01-26 Kabushiki Kaisha Toshiba Metal Oxide varistor
EP0070468A3 (en) * 1981-07-16 1983-08-24 Kabushiki Kaisha Toshiba Metal oxide varistor
US4516105A (en) * 1981-07-16 1985-05-07 Tokyo Shibaura Denki Kabushiki Kaisha Metal oxide varistor with non-diffusable electrodes
US4436650A (en) 1982-07-14 1984-03-13 Gte Laboratories Incorporated Low voltage ceramic varistor
US4724511A (en) * 1985-10-24 1988-02-09 Itt Industries, Inc. Dielectric compositions
US5644284A (en) * 1994-04-27 1997-07-01 Matsushita Electric Industrial Co., Ltd. Temperature sensor

Also Published As

Publication number Publication date
FR2032355B1 (zh) 1977-01-21
DE2009319A1 (de) 1970-11-19
DE2009319B2 (de) 1973-01-04
GB1290945A (zh) 1972-09-27
NL152395B (nl) 1977-02-15
FR2032355A1 (zh) 1970-11-27
NL7002605A (zh) 1970-08-26

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