Vibration damper test machine

Claim 2

A torsional vibration damper test machine comprising a rotary mass elastic system adapted at one end to receive a torsional vibration damper to be tested, an electric drive motor coupled to the opposite end of said system for rotating same to a predetermined rotational speed and thereafter permitting said system to decelerate from said predetermined speed, electromagnetic means coupled to said system for inducing vibration excitation therein during deceleration thereof, said excitation having a predetermined frequency and amplitude resonant with said system at a given speed less than said predetermined speed to thereby induce maximum strain in said system, and means for measuring said maximum strain as an indication of the effectiveness of said damper.

Claim 3

A test machine according to claim 1, further defined by said electromagnetic means comprising a plurality of members of magnetically permeable material extending radially from said system for rotation therewith, and means for generating a magnetic field transversely through said members during rotation thereof, whereby said field attracts said members to apply a positive torque and then tends to retain said members to apply a negative torque to said system.

Claim 4

A test machine according to claim 2, further defined by said members being arms of a disc coaxially secured to said system, and means for generating a magnetic field comprising a pair of magnetic yokes disposed on transversely opposite sides of said disc, pairs of pole piece shoes secured to said yokes on transversely opposite sides of the rotary path of said members, a pair of coils magnetically coupled to said yokes, and means for electrically energizing said coils.

Claim 5

A test machine according to claim 1, further defined by a clutch for selectively coupling said motor to said system, and a brake for selectively braking said system to decelerate same.

Claim 6

A test machine according to claim 4, further defined by automatic control means for energizing said motor, engaging said clutch, and releasing said brake responsive to a start signal; de-energizing said motor, disengaging said clutch, and applying said brake responsive to said first predetermined speed; releasing said brake and actuating said electro-magnetic means responsive to a second predetermined speed less than said first predetermined speed, and applying said brake and deactuating said electromagnetic means responsive to a third predetermined speed less than said second predetermined speed.

Claim 7

A test machine according to claim 1, further defined by said mass elastic system comprising a shaft having a hub at one end for securance to said damper, means journaling said shaft for rotation, a flywheel having a second shaft projecting coaxially therefrom, means journaling said second shaft for rotation, said motor coupled to said second shaft, and a third shaft of reduced diameter relative tO said first shaft coaxially secured between the second end of said first shaft and said flywheel, the strain measuring means including a strain gauge secured to said third shaft, and means for indicating the current from said strain gauge.

Claim 8

A test machine according to claim 6, further defined by the electromagnetic means comprising a disc coaxially secured to said second end of said first shaft, said disc having a plurality of radially extending members of magnetically permeable material, and means for generating a magnetic field transversely of the rotational path of said members, whereby said field alternately attracts said members to apply positive torque to said first shaft and tends to retain said members to apply negative torque to said first shaft.

Claim 9

A test machine according to claim 7, further defined by the field generating means comprising a pair of U-shaped magnetic yokes disposed on transversely opposite sides of said disc, pairs of pole piece shoes secured to said yokes on transversely opposite sides of the rotational path of said members, a pair of coils magnetically coupled to said yokes, and means for selectively energizing said coils.

Claim 10

A test machine according to claim 6, further defined by an electromagnetic clutch coupling said motor to said second shaft, an electromagnetic brake coupled to said second shaft, and rotational speed sensing means associated with said second shaft for producing a signal indicative of the speed thereof.

Claim 11

A test machine according to claim 9, further defined by the electromagnetic means comprising a disc coaxially secured to said second end of said first shaft, said disc having a plurality of radially extending members of magnetically permeable material, and electromagnet means including electrically energizable coils for generating a magnetic field transversely of the rotational path of said members responsive to energization of said coils.

Claim 12

A test machine according to claim 10, further defined by said clutch being engaged responsive to electrical energization and disengaged responsive to de-energization, said brake being applied responsive to electrical energization and released responsive to de-energization, and automatic control circuit means responsively coupled to said speed sensing means and coupled in energizing relation to said motor, clutch, brake, coils, and strain gauge current indicating means, said control circuit means being arranged to energize said motor and clutch and de-energize said brake in response to a start signal, de-energize said motor and clutch and energize said brake in response to the speed signal from said speed sensing means representing said first predetermined speed, de-energize said brake and energize said coils and strain gauge current indicating means in response to said speed signal representing a second predetermined speed less than said first predetermined speed, and energize said brake and de-energize said coils and strain gauge current indicating means in response to said speed signal representing a third predetermined speed less than said second predetermined speed.

Claim 13

A test machine according to claim 11, further defined by said control circuit means comprising a controller having an energization input terminal, first and second output terminals, and a speed signal input terminal, said speed signal input terminal coupled in receiving relation to said speed sensing means, said controller arranged to open a circuit between said energization input terminal and first output terminal and close a circuit between said energization input terminal and second output signal in response to said second predetermined speed, a timer having normally open contacts and normally closed contacts, said controller arranged to initiate a predetermined time delay in said timer in response to said first predetermined speed, said timer arranged to open said normally closed contacts and close said normally open contacts thereof responsive to termination of said time delay, a power supply, a relay having first, second and third normally open contacts, a second relay having normally open contacts and normally closed contacts, a third relay having first and second normally open contacts and normally closed, contacts, a fourth relay having first, second and third normally open contacts and normally closed contacts, a fifth relay having normally closed contacts, a depressible cycle start switch, and a second controller having an energization input terminal, an output terminal, and a speed signal input terminal coupled in receiving relation to said speed sensing means, said second controller arranged to close a circuit between said energization input and output terminals thereof responsive to said third predetermined speed, said start switch, normally closed contacts of said fifth relay, and said first relay series connected between said supply and ground, said supply connected to said input terminals of said first and second controllers, said first normally open contacts of said first relay connected in parallel with said start switch, said second normally open contacts of said first relay and normally closed contacts of said third relay series connecting said second relay between said supply and ground, said normally open contacts of said second relay connecting said supply to said clutch, said normally closed contacts of said second relay and normally closed contacts of said fourth relay series connecting said supply to said brake, said first normally open contacts of said fourth relay connecting said supply to said strain gauge current indicating means, said second normally open contacts of said fourth relay connecting said supply to said coils, said third normally open contacts of said fourth relay connecting said fifth relay between ground and said output terminal of said second controller, said third normally open contacts of said first relay connecting said first output terminal of said first controller to said normally open and normally closed contacts of said timer, said normally closed contacts of said timer connected to said motor, said third relay connected between said normally open contacts of said timer and ground, said first normally open contacts of said third relay connected between said input terminal and first output terminal of said first controller, said second normally open contacts of said third relay and said fourth relay series connected between said second output terminal of said first controller and ground.