Grinding wheel balancing method and apparatus

• US 5,243,788 A
• Filed: 08/15/1990
• Issued: 09/14/1993
• Est. Priority Date: 09/11/1989
• Status: Expired due to Fees

• Current Assignee: GEBR. Hofmann GmbH & Co. KG Maschinenfabrik
• Original Assignee: GEBR. Hofmann GmbH & Co. KG Maschinenfabrik
• Inventors: Hofmann, Andreas, Rossmann, Gunther, Varona, Jesus
• Primary Examiner(s): PARKER JR, ROSCOE
• Application Number:
  US07/567,896
• Time in Patent Office: 1,126 Days
• Field of Search: 51/169, 73/462
• US Class Current: 451/343
• CPC Class Codes: G01M 1/36 by adjusting position of masses built-in the body to be tested

Abstract

In a method and an apparatus for balancing a grinding wheel, balancing weights on the grinding wheel remain secured to the grinding wheel in an unbalance measuring operation, and the positions at which the balancing weights are secured to the grinding wheel are stored. In a repositioning operation for compensating for measured unbalance of the grinding wheel, the influences of the forces of the balancing weights during the unbalance measuring operation are derived from the stored positions of the weights and compensated for so as to balance the ginding wheel.

Claims

1. A method of balancing a grinding wheel comprising the steps of:

performing an unbalance measuring operation to determine the unbalanced nature of the grinding wheel;

securing at least two balancing weights to the grinding wheel along at least one radius around the axis of the grinding wheel in balancing positions calculated from the measuring operation;

locating and storing positions of said at least two weights;

determining proper balancing positions of said at least two weights to balance the grinding wheel by effectively removing said at least two weights without actual physical movement of said at least two balancing weights; and

repositioning said at least two weights to said proper balancing positions to balance the grinding wheel, wherein the step of determining proper positions of said at least two balancing weights includes vectorially adding unbalance vectors associated with force vectors resulting from the stored positions and respective masses of said at least two balancing weights together with a measured unbalance vector, thereby determining a grinding wheel unbalance vector and thereafter, repositioning said at least two balancing weights on the grinding wheel to compensate the grinding wheel unbalance vector, and wherein first and second balancing weights are utilized and each said balancing weight is arranged at a respective angle (α and

β

respectively) with respect to the angular position which is turned through 180°

of the grinding wheel unbalance vector, the angles in the case of equal balancing weights satisfying the following equations;

##EQU5## and in the case of different balancing weights satisfying the following equations;

##EQU6## wherein Us designates the magnitude of the grinding wheel unbalance vector, S1 designates a scalar value which results from a mass of the one balancing weight and a radius at which that weight is movable around the axis of rotation of the grinding wheel, and S2 designates a scalar value which results from a mass of the other balancing weight and a radius at which that weight is movable around the axis of rotation of the grinding wheel.

2. A method as set forth in claim 1, wherein said at least two balancing weights are movable on constant radii about the axis of rotation of the grinding wheel.

3. A method as set forth in claim 1, wherein said at least two balancing weights are movable on a common radius about the axis of rotation of the grinding wheel.

4. A method as set forth in claim 1, wherein said at least two balancing weights are of the same mass.

5. A method of balancing a grinding wheel comprising the steps of:

performing an unbalance measuring operation to determine the unbalanced nature of the grinding wheel;

securing at least two balancing weights to the grinding wheel along at least one radius around the axis of the grinding wheel in balancing positions calculated from the measuring operation;

locating and storing positions of said at least two weights;

determining proper balancing positions of said at least two weights to balance the grinding wheel by effectively removing said at least two weights without actual physical movement of said at least two balancing weights; and

repositioning said at least two weights to said proper balancing positions to balance the grinding wheel, wherein the step of determining proper positions of said at least two balancing weights includes vectorially adding unbalance vectors associated with force vectors resulting from the stored positions and respective masses of said at least two balancing weights together with a measured unbalance vector, thereby determining a grinding wheel unbalance vector and thereafter, repositioning said at least two balancing weights on the grinding wheel to compensate the grinding wheel unbalance vector, and wherein first, second and third balancing weights are utilized and one said balancing weight is arranged at an angular position which is turned through 180°

relative to the angular position of the grinding wheel unbalance vector and the other two balancing weights are arranged at respective angular positions (α and

β

respectively) related to the angular position of said vector turned through 180°

, said angular positions in the case of equal balancing weights satisfying the following equations;

##EQU7## and in the case of different balancing weights satisfying the following equations;

##EQU8## wherein, Us designates the magnitude of the grinding wheel unbalance vector and S1, S2 and S3 respectively designate scalar values which result from respective masses of the first, second and third balancing weights and respective radii at which the balancing weights are movable around the axis of rotation of the grinding wheel.

6. A method as set forth in claim 5, wherein said at least two balancing weights are movable on constant radii about the axis of rotation of the grinding wheel.

7. A method as set forth in claim 5, wherein said at least two balancing weights are movable on a common radius about the axis of rotation of the grinding wheel.

8. A method as set forth in claim 5, wherein said at least two balancing weights are of the same mass.

9. A method of balancing a grinding wheel comprising the steps of:

performing an unbalance measuring operation to determine the unbalanced nature of the grinding wheel;

securing at least two balancing weights to the grinding wheel along at least one radius around the axis of the grinding wheel in balancing positions calculated from the measuring operation;

locating and storing positions of said at least two weights;

determining proper balancing positions of said at least two weights to balance the grinding wheel by effectively removing said at least two weights without actual physical movement of said at least two balancing weights; and

repositioning said at least two weights to said proper balancing positions to balance the grinding wheel, wherein said at least two balancing weights are movable on variable radii about the axis of rotation of the grinding wheel.

10. A method as set forth in claim 9, wherein said at least two balancing weights are movable on constant radii about the axis of rotation of the grinding wheel.

11. A method as set forth in claim 9, wherein said at least two balancing weights are movable on a common radius about the axis of rotation of the grinding wheel.

12. A method as set forth in claim 9, wherein said at least two balancing weights are of the same mass.

13. Apparatus for balancing a grinding wheel by means of first and second balancing weights adapted to be guided on and secured to the grinding wheel comprising:

a measurement value detector means;

an unbalance measuring means connected thereto;

an evaluation means adapted to determine the positioning of said balancing weights in dependence on the measured unbalance of the grinding wheel;

operatively associated with each balancing weight a respective vector storage means for storing in dependence on the mass and positioning of the respective balancing weight on the grinding wheel an unbalance vector which is compensated thereby;

a vector adding means connected to the first and second vector storage means and to the output of the unbalance measuring means;

a 180°

-circuit connected to the output of the vector adding means and operable to turn through 180°

the direction of the vector formed by the vector adding means and to supply a corresponding angle signal, the 180°

-circuit including a first and a second output;

an angle adding means having a first input connected to the first output of the 180°

-circuit and a second input;

a first angle calculating means connected to the second input of the angle adding means to supply same with a signal corresponding to the angle of the first balancing weight, wherein the first angle calculating means is operable to calculate said angle of said first weight from the absolute value of the output signal supplied by the vector adding means and a scalar value formed from the mass of said first balancing weight and the radius at which said weight is guided on the grinding wheel around the axis of rotation of the grinding wheel;

an angle subtracting means having a first input connected to the second output of the 180°

-circuit and a second input; and

a second angle calculating means connected to the second input of the angle subtracting means to supply the same with a signal corresponding to the angle of the second balancing weight, wherein the second angle calculating means is operable to calculate said angle of said second weight from the absolute value of the output signal supplied by the vector adding means and a scalar value formed from the mass of the second balancing weight and the radius at which said second weight is guided on the grinding wheel around the axis of rotation of the grinding wheel.

14. Apparatus for balancing a grinding wheel installed in a grinding machine by means of first, second and third balancing weights which are adapted to be guided on and secured to the grinding wheel comprising:

a measurement value detector means;

an unbalance measuring means connected thereto;

an evaluation means for determining the balancing weights in dependence on the measured unbalance;

operatively associated with the three balancing weights respective vector storage means for storing in dependence on the mass and positioning of the respective balancing weight on the grinding wheel an unbalance vector which is compensated thereby;

a vector adding means connected to the first, second and third vector storage means and to the output of the unbalance measuring means;

a 180°

-circuit connected to the output of the vector adding means and operable to turn through 180°

the direction of the vector formed by the vector adding means and to supply a corresponding angle signal representing a first angular position for positioning of one of the balancing weights, the 180°

-circuit including first and second outputs;

an absolute value calculating means connected to the output of the vector adding means for forming the scalar value of the vector supplied by the vector adding means;

a subtracting means connected to the output of the absolute value calculating means for calculating the difference of the scalar value of the vector supplied by the vector adding means and a scalar value formed from the mass of the weight to be arranged at said first angular position and the radius at which said balancing weight is guided on the grinding wheel around the axis of rotation thereof;

an angle adding means having a first input connected to the first output of the 180°

-circuit and a second input;

a first angle calculating means connected to the subtracting means and the second input of the angle adding means to supply same with a first angle signal corresponding to a first cosine value formed, said first angle signal being calculated from scalar values supplied to the first angle calculating means and which are formed from the masses of the two balancing weights and the radii at which said balancing weights are guided around the axis of rotation of the grinding wheel;

an angle subtracting means having a first input connected to the second output of the 180°

-circuit and a second input; and

a second angle calculating means connected to the subtracting means and the second input of the angle subtracting means to supply the same with a second angle signal corresponding to a second cosine angle formed, said second angle signal being calculated from a scalar value supplied to the second angle calculating means and which is formed from the mass of the other of the two remaining balancing weights and the radius at which said balancing weight is guided around the axis of rotation of the grinding wheel.