1、MIL-S-7b7A bb 77777Ob 0326532 T MI L-s- 7 8 6 7A (AER) I OCTOBER 1957 SUPERSEDES . MIL-S-7867 (AER) I JANUARY 1932 1. SCOPE _ MILITARY SPECIFICATION SERVO ACTUATOR, D-9 This specification has been approved by the Bureau of Aeronautics,. Department of the Navy. 1.1 Scope - The equipment covered by th
2、is specification shall m ve aerodynam-c con- trol surfaces of trirgetdrones in response to radio command aignais. . 2. APPLICABLE DOCUMENTS 2.1 General - The fobwing documenta at the iasue in eUect on the i1 and Asaociaed Eqnipmemt, Gemera1 4m3fkiI , mitiEltioilf MIL-P-6064 Fa Hfscellaneous Ektrical
3、 Equipment (Except Rotating Electrical Equipment) and Associated Repair Parts Test Procedures, Preprochiction and Inspectton for Aircraft Eieckamc Equioment; Format for MIL- W-5088 Wiring, Aircraft, Instailation of MIL-N-18307 Nomenclature and Nameplates for Airborne Elec- ironic and Associated Equi
4、pment 1 Licensed by Information Handling ServicesMIL-S-7b7A 66 W 7777706 0326533 1 W MIL-E-7894 MIL-S- 7867A(Aer) Electric Power, Aircraft Characteristics of - Bureau of Aeronautics SAR-300 Engineering Change Proposals, Electronic Material Changes and Electronic Material Bulletins; Preparation of ST
5、ANDARDS MIL-STD-129 Marking for Shipment and Storage 2.2 Availability of Documents: (1) Give both the title and number .Wen requesting specifications, standards, drawings and publications. All requests should be made via the cognizant Inspector of Naval Material or Bureau of Aeronautics Representati
6、ve. (2) Copies of this specification and applicable documents may be obtained upon application to the Commanding Olficer, Naval Aviation Supply Depot, Philadelphia 11, Pennsylvania, Attention: Code ODPT. 2.3 Precedence - When the requirements of the contract, this specification, or (1) Contract - Th
7、e contract shall have precedence over any specification. applicable subsidiary specification are in conflict,the following precedence shall apply. (2) This Specification - This specification shall have precedence over all applicable subsidiary specifications. Any deviation from this specification, o
8、r from sub- sidiary specifications where applicable, shall be specifically approved in writing by the Bureau of Aeronautics. (3) Referenced Specifications - Any referenced specification shall have precedence over all applicable subsidiary specifications referenced therein. All referenced specificati
9、ons shall apply to the extent specified. 3. REQUIREMENTS 3.1 Parts and Materials - In the selection of parts and materials, fulfillment of major design objectives shall be the prime consideration. In so doing the following shall govern : (1) Parts and materials as approved by Specification MIL-E-540
10、0 shall be given fir s t consider ation. (2) When the characteristics of standard MIL parts and materials are such that their use will not fulfill the requirements because of size, weight, perform- ance or other reasons, material and parts shall be used which most nearly meet or exceed the requireme
11、nts of the respective standard parts and material specifications. (3) When a non-standard part is used, the meeting of general material require- ments such as non-inflammability, fungus resistance, non-toxicity, etc. , and, the meeting of environmental conditions as required by Specification MIL-E-5
12、400 or MIL-E-5272 shall be of prime consideration. (4) in the selection of parts, the above considerations shall apply if the assembly is to be built for detail part maintenance. In the event the entire assembly is built to be expended, the assembly shall be constructed and the quality of the indivi
13、dual parts shall be such that the unit as a whole will pass material, elec- 2 Licensed by Information Handling ServicesMIL-S-7867A 66 W 777770b 0226534 3 W MTL-S- 78 67A(Aer) trical and environmental tests. Any assembly built to be expended shall be approved first by the Bureau of Aeronautics. 3.1.1
14、 Non-Standard Part and Material Approval - Approval for the use of non-standard parts and materials shall be obtained as outlined in Specification MIL-E -5400 except as follows: (1) Mechanical parts shall be submitted as non-standard parts only when the material requirements of Specification MIL-.E-
15、5400 are not met. (2) Non-standard parts of an electrical nature as defined in Specification MIL-E-5400 must be approved before the preproduction model of the equipment is submitted for tests. The request for approval must be forwarded to the Bureau of Aero- nautics before the part is purchased or f
16、abricated. In addition to or in lieu of the Non-Standard Part Data Sheet, the contractor shall submit an itemized list of the parts, their sources, and the contractors drawing or purchase specifi- cation covering the parts. 3.2 Desian and Construction: 3.2. 1 General - This equipment shall fulfill a
17、ll applicable design and construction require- 3.2.2 Service Conditions - The equipment shall operate satisfactorily under any of the environmental and mechanical service conditions or reasonable combination of these conditions as specified in Specification MIL-E-5400 for Clas 1 equipment. ments of
18、Specification MIL-E-5400 unless otherwise specified herein. 3.2.3 Standard Conditions - Tbe following conditians shall be used as a basis to establish normal performance requirements and ior making laboratory bench testa on the equipment: Temperature Altitude Norma gr6und Vibration None, Humidity In
19、put power voltage Room ambient 25C +15“C or -5C Room ambient up to 90% relative humidity 27.5 f O. 5 V DC 3.2.4 Total Weight - The toal weight of the equipment including the control rm shall be a minimum consistent with good design and shall not exceed 2.5 pounds. 3.2. 5 Operational Stability- -The
20、equipment shall operate with optimum performance for 5 hours, continuously or intermittently, without necessity for readjustment of any controls which are inaccessible during flight. 3.2. 6 meratine: Life 3.2.6.1 Reliable Operating Life - The equipment shall have a reliable operating life of at leas
21、t 50 hours without removal for bench servicing. Parts requiring servicing or replacement at the end of this interval to renew this service life shall be specified by the manufacturer. 3.2.6.2 Total Operating Life - The equipment shall have a minimum total operang life of 100 hours with reasonable se
22、rvicing and replacement of parts. Parts requiring. replacement within this interval and the life of such parts shall be specified by the manufacturer. 3.2. 7 Interconnection Cabling - This equipment shall be capable of satisfactory opera- tion using external wiring in accordance with the applicable
23、requirements of Specification ML-W-5088. The external wiring shall be unshielded except that a minimum number of the individual wires may be shielded, when demonstrated as necessary to meet interference control requirements and provided the assembly of the cable to its plugs may be easily accomplish
24、ed. 3 7 Licensed by Information Handling ServicesNIL-S-7b7A bb 7777706 0326535 5 - -_ 4 T , o - ?.fIL-S- 7867A(Aer) 3.2.8 Cables and Connectors - The equipment shall provide for the use of cables and connectors in accordance with the requirements of Specification MIL-E-5400. However, cables and that
25、 portion of the connectors which is to be attached to the cables shall not be supplied as part of the equipment. 3.2.9 Input Power Requirements - The equipment shall meet all applicable require- ments of Specification MIL-E-7894 and shall give specified performance from the following power sources w
26、ith characteristics as defined in Specification MIL-E-7894 having limits as specified herein. The power required shall not exceed the specified amounts. (1) DC Power 28 Volts System Operating Voltage Limits Current 1.20 amps 22. 5 to 29 volts 3.2.9.1 Power Source. Transients - The servo shall not be
27、 damaged when subjected to source transients and shall automatically resume normal operation at the expiration of the transient condition. 3.2.10 Grounded Input - The design of the servo shall be such that the negative supply to the motor shall be obtained from internal case ground. 3.2.11 Under Vol
28、tage Protection - The equipment shall not be damaged by voltages below the minimum specified and shall automatically resume normal operation when the voltage returns within limits. 3.2.12 Moisture and Fungus Resistant Treatment - Equipments shall be fungus-proofed by selection of parts and materials
29、 as non-nutrient for fungus or the parts and materials shall be treated prior t their use in the equipment so that overall spraying of the equipment is not necessary. Overall spraying of the equipment in accordance with Specification MIL-T-162 shall be made in the event selection of parts and materi
30、als described above is not possible. 3.2.13 Nomenclature and Nameplates - Nomenclature assignment and nameplate approval for equipment identification shall be in accordance with Specification MIL-N-18307. 3.2.14 Interchangeability - The interchangeability requirements between like assemblies, subass
31、emblies and replaceable parts as specified in Specification MIL-E- 5400 shall be extended to require interchangeability of units of this equipment with the latest model of any previously produced equipment. Such interchangeability shall be measured against a model, manufacturing drawings, or other t
32、echnical information as provided by the Bureau of Aeronautics for the purpose. In the event that requirements of Specification MIL-E-5400 conflict with the requirements for interchangeability, the interchangeability requirements shall govern. 3.2.15 Provisions for Maintenance and Field Testing - The
33、 equipment shall be design- ed to provide for ease of maintenance to the greatest practicable extent. Provisions for field test- ing shall be as specified in Specification MIL-E-5400. 3.2.16 . Radio Interference Control - The generation of radio interference by the equipment and the vulnerability of
34、 the equipment to radio interference shall be controlled within the limits of Specification MIL-1-6181 over the frequency range of 50 to 1000 megacycles. 3.3 Perfor mance 3.3.1 Rated Load - The servo shall be capable of producing a minimum torque of 70 wund-inches with an output shaft speed of 8.5 r
35、pm. 3.3.2 Non-Reversibility - The servo output shaft shall be non-reversible under torque loads equal to 30 pound-inches with no voltage applied to the motor. Licensed by Information Handling Servicest MIL-S-7867A 66 m 7999906 0126536 7 c_ - 3.3.3 Stall Torque - The servo motor shall not stall under
36、 torque loads of up to Braking - The servo output shaft shall not coast more than 2“ when the control Centering - Provision shall be mad2 to center the output shaft upon application twice rated load while operating on 26. 5 volts dc. 3.3.4 signal is removed withmrvo operating under 30 pound-inches a
37、iding load. 3.3.5 of an external command. 3.3. 6 Speed - The servo shall have a no load speed of no greater than 10.5 rpm. The speed at rated loam not be less than 7.5 rpm. 3.3.7 Endurance - The servo shall operate for a period of 50 hours when pulsed by commands at 15 cps operating on an “on-off“ d
38、uty cycle of approximately I 50-50g. The servo shall operate at the rate of approximately one complete oscillation every 5 seconds with the torque arm restrained by a spring whose tension is no less than 3 pound-inches per degree. conform to the requirements of Specification MIL-E-5400. 3.4 Workmans
39、hip - Workmanship, fabrication and manufacturing processes shall 3.5 Detail Requireir.ents - The motor, gear train, and output shaft of the servo. e shall provide an output shaft speed of 8-1/2 rpm while delivering 70 inch-pounds load. 3.5. 1. Form Factor and Mounting - The servo shall be contained
40、in a waterproof case and shall incorporate four points of attachment located on the output shaft end. Attachment Points - The four points .d attachment shall be finished in a manner such as to assure a good electrical bond between the servo and the attaching surface. Contents of Unit - The servo sha
41、ll consist of the following major components: (1) D.C. Motor (2) Gear Train 3. 5. 1.1 3.5.2. (3) Outputshaft (4) Control Arm (5) Follow-up Potentiometer- (6) Relays (7) Arc Suppression Netwrk (8) Limitswitch (9) Centering Switch (10) Receptacle. . 3.5.2.1 Motor - A direct-current electric motor, des
42、igned to operate on 22.5 to 30 volts, shall be providemshall be equipped with oil or graphite impregnated bearings, or grease packed ball bearings. The motor shall be suitably geared to the output shaft to give the performance specified. 3. 5.2.2 Gear Train - 3.5.2.2.1 Mechanical Strength - The gear
43、 train and bearings shall be capable of with- standing shock loads on the control arm equivalent to a weight of 5.5 pounds dropping 5 inches on 5 Licensed by Information Handling ServicesMIL-S-7B67A 66 9999906 0326537 7 m the 1.45 inch cbntrol arm station with 100 pound-inches already on the arm. 3.
44、 5.2.2.2 .Backlash - Gear train backlash shall be held to less than 1“ total for the servo 3.5.2.3 as measured by traversing the control arm. Output Shat - The output shaft shall be provided with standard 36 S. A. E. Control Arm - A control arm shall be provided with standard 36 S. A. E. serrations.
45、 3.5.2.4 serrations similar to hose on the output shaft. 3.5.2. 5 Follow-up Potentiometer - A precision wirewound potentiometer of 1-watt rating shall be furnished as an integral part of fhe servo. This unit shall have a total resistance of 1200. ohms, i 4 %, with a linearity of 1/2 % of ful scale,
46、and a resolution of 1/2“. The windings shall cover an arc of 50 + 3 - O“,. ahd-have a 10“ override on each end of the windings without causjng an open circuit. as the control arm. shall be provided as amthe servo to reverse the motor. The relay actuating current shall be less than O. 25 ampere of di
47、rect current. protect the relay contacts from burning, pitting or welding when operating under any of the conditions specified herein. The wiper shall be connected to the output shaft so that it rotates at the same speed Relays - Two relays capable of operating through a range of 18 to 30 volts DC,
48、3.5.2.6 3.5.2.7 Arc Suppression - The servo shall contain an arc suppression network to 3.5.2.8 Limit Switch - A combination limit switch shall be provided so that the control signal shall be automatically released when the output shaft has rotated to a preset clockwise or counterclockwise position.
49、 3. 5.2.8. 1 Control Arm Travel - The limit switch shall be adjusted to limit the travel of the control arm to 22.5“ + 2,5 either side of center when the control voltage is impressed on the motor. - 3.5.2.9 Centering - The mechanical: center of the control arm travel, as determined by the centering switch, shall be adjusted so that with the servo centered, fhe potentiometer wiper shall be within i 1“ of the electrical center of the potentiometer. 3.5.2.9.1 Positioning of Control Arm - After the servo has completely responded to an external centering command, the out
