Dual drive mechanism with a redundant feature

• US 5,028,828 A
• Filed: 05/25/1989
• Issued: 07/02/1991
• Est. Priority Date: 05/25/1988
• Status: Expired due to Term

• Current Assignee: DaimlerChrysler Aerospace AG (Mercedes-Benz Group AG)
• Original Assignee: ERNO Raumfahrttechnik GmbH
• Inventors: Lenk, Uwe, Petrowitsch, Hilmar, Felkai, Roland
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): REBSCH, DONALD
• Application Number:
  US07/357,312
• Time in Patent Office: 768 Days
• Field of Search: 74/661, 244/175 R, 244/173, 310/83, 310/112, 310/114, 310/118, 310/121, 901/23, 901/24, 901/49
• US Class Current: 310/83
• CPC Class Codes: H02K 16/00 Machines with more than one rotor or stator machines for transmitting mechanical power from a driving shaft to a driven shaft and comprising structurally interrelated motor and generator parts H02K51/00; permanent magnet machines with multiple rotors or stators relatively rotated for vectorially combining the excitation fields or the armature voltages H02K21/029
• CPC Class Codes: H02K 7/10 Structural association with clutches, brakes, gears, pulleys or mechanical starters
• CPC Class Codes: Y10T 74/19014 Plural prime movers selectively coupled to common output

Abstract

A drive mechanism is redundantly equipped with two electric motors so that the second motor can take over the drive function if the first motor should fail, for example for moving equipment in or on a spacecraft. Both electric motors are connected to a common drive shaft. A coupling device makes sure that the defective motor is decoupled from the drive train.

Claims

1. A drive mechanism with a redundant feature, comprising:

(a) a housing (27), gear means including two driving gears (8,

     9) mounted for rotation in said housing (27), coupling means mounted in said housing for cooperation with said gear means, two electric drive motors (1,

     2) secured in parallel to each other to one side of said housing (27), each electric motor (1,

     2) having a multi-spline drive shaft (4,

     5);

(b) each multi-spline shaft reaching into said housing for cooperation with its respective coupling means for connecting and disconnecting each of said electric motors with its respective gear means, said coupling means comprising two coupling control sleeves (6,

     7), one control sleeve being mounted for an axial displacement on each of said multi-spline drive shafts (4,

     5);

(c) each coupling control sleeve (6,

     7) having an outer threading (29, 29a), each of said driving gears (8,

     9) having an inner threading (30, 30a) for threadingly engaging said outer threading (29, 29a) of the respective coupling control sleeve (6,

     7) for controlling an engaging and a disengaging of said gear means with a drive train;

(d) said drive mechanism further comprising a driven output shaft (25) extending out of said housing (27), said gear means further including a driven gear (3) on said output shaft (25) arranged for meshing with said two driving gears (8,

     9) to drive said output shaft (25);

(e) said coupling means comprising gear arresting and releasing lever means (10,

     11), each lever means (10,

     11) including a free end and an arresting element (13, 13a) at its free end, journal members (12,

     15) for tiltably mounting said gear arresting and releasing lever means (10,

     11) to another side of said housing (27) opposite said first mentioned side of said housing, and spring means (28, 28a) for normally holding each gear arresting and releasing lever means (10,

     11) into a gear engaging position;

(f) each of said coupling control sleeves having a pushing tip (31, 31a) for pushing a respective one of said gear arresting and releasing lever means (10,

     11) into a gear releasing position in response to a threading movement between said outer and inner threadings (29, 29a, 30, 30a), whereby one of said movable coupling control sleeves (6,

     7), whose electric motor (1,

     2) is still operational, pushes its tip (31, 31a) through a hole in said housing (27) for operating the respective one of said gear arresting and releasing lever means (10,

     11);

(g) said drive mechanism further comprising locking disks (16, 16a) for normally locking said driving gears (8,

     9) against an axial movement, biasing spring means (14, 14a) for normally urging said locking disks (16, 16a) out of a gear engaging position, said arresting elements (13, 13a) each fixing a respective one of said locking disks (16, 16a) in said gear engaging position against a biasing force of said biasing spring means (14, 14a);

(h) said coupling means further comprising at least one coupling lever having two arms (17,

     18) journalled (at

     21) in said housing (27) for interconnecting said coupling control sleeves (6,

     7), said lever arms (17,

     18) having pins (19,

     20) for engaging a respective one of said coupling control sleeves (6,

     7), whereby said coupling lever with its two arms (17,

     18) is connected to said gear means (8,

     9) for axially displacing a respective gear means out of a drive train when the respective locking disk (16, 16a) is released from the respective gear means (8,

     9);

(i) said two arms (17,

     18) of said coupling lever being tiltable independently of each other within a certain angular tilting range until a stop is reached, whereupon said two arms (17,

     18) are tiltable in unison; and

(j) wherein said coupling control sleeve (6,

     7) of a still operational motor is screwed still further into its respective gear (8,

     9) when said locking disk (16, 16a) of a blocked drive side is unlocked, whereby said coupling lever (17,

     18) of said blocked drive side including its coupling control sleeve (6,

     7) and gear means (8,

     9) are pulled out of the drive train toward the respective electric drive motor (1,

     2) until a spring biased pin (22a, 23a) of an arresting unit (22,

     23) fixes the respective coupling control sleeve (6,

     7) in its maximal retracted position.

2. The drive mechanism of claim 1, further comprising a return movement locking pin (26) for fixing a respective one of said movable coupling control sleeves (6, 7) in its maximum moved-out position when it is screwed deep into its respective gear means (8, 9) of that part of said drive mechanism which is still operational.

3. The drive mechanism of claim 1, wherein said gear arresting and release lever means (10, 11) comprises two levers arranged in a laterally overlapping relationship, so that said pushing tip (31, 31a) of one coupling control sleeve (6, 7) can release said locking disk (16, 16a) of the respective other driving gear and vice versa.

4. The drive mechanism of claim 1, wherein said arresting elements (13, 13a) are pins which normally engage a hole in the respective locking disk (16, 16a), and wherein said pins are lifted out of the respective locking disk by the tilting movement of the respective lever means (10, 11).