Wheel balancing apparatus and method with improved hidden spokes placement for irregular wheels

Abstract

A method and an apparatus for carrying out the method are disclosed for hidden spokes placement of balancing weights on a wheel, having a hub, a rim and the hub and the rim being connected by several spokes, comprising determination of spoke configuration data. Now, it is possible to analyze spoke configuration and width of the spokes in details, enabling the weight splitting behind spokes even if spokes are forked, oblique, not equidistant, or they have different dimension.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and features will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims only. It should be further understood that the drawings are merely intended to conceptually illustrate the structures and procedures described herein.

FIG. 1 shows an example for a vehicle wheel with five equidistant spokes, wherein on optimal hidden spokes placement of a balancing weight is depicted;

FIG. 2 a-2g shows several examples for vehicle wheels with spoke configurations, where automatized determination of the spoke locations can be susceptible for errors;

FIG. 3 a-3b shows examples for bad placement of balancing weights due to wrong interpretation of sampled spokes data;

FIG. 4 illustrates in more detail hidden spokes placement by means of the present invention such that sampled spokes data is interpreted correct and the balancing weight of FIG. 3b is split in two hidden placed balancing weights;

FIG. 5 illustrates an example for analysis of the sampled spokes data, in particular identification of spoke patterns; and

FIG. 6 a shows identification of five equidistant spokes in the sampled spokes data of FIG. 5;

FIG. 6 b illustrates the analysis of sampled spokes data of an identified group/period in the spokes data of FIG. 6a in more detail;

FIG. 7 a shows another example for analyzed sampled spokes data and identification of 6 pairs of spokes;

FIG. 7 b illustrates the analysis of sampled spokes data of an identified group/period the spokes data of FIG. 7a in more detail;

FIG. 8 a-8d is illustration for a first detailed working example of the appendix to the description; and

FIG. 9 a-9d is illustration for a second detailed working example of the appendix to the description.

Claims

1. Method for hidden spokes placement of balancing weights on a wheel, having a hub, a rim and the hub and the rim being connected by several spokes, the method comprising determination of spoke configuration data by the steps of: sampling of spokes data at a sampling position being at fixed distance from the rim;transforming the sampled spokes data from spatial domain into frequency domain for providing frequency characteristics of the spokes data; andderiving the spoke configuration data from the frequency characteristics and the spokes data.

2. Method according to claim 1, wherein the sampling step is performed in several different positions each with a predetermined distance relative to the bead of the rim.

3. Method according to claim 1 or 2, wherein the sampling step further comprises evaluating each data point of the sampled spokes data by assigning a predetermined value representing one of a predetermined condition.

4. Method according to one of the preceding claims, wherein the sampling step comprises revolving of the wheel for several revolutions in the sampling position and wherein in each revolution the sampled spokes data is further completed where reliable sample values are still missing.

5. Method according to one of the preceding claims, wherein the transforming step comprises performing a Fourier Transform on the scan data providing Fourier data of the spokes data.

6. Method according to claim 5, wherein the deriving step comprises identifying periodical patterns corresponding to spoke groups by a harmonic frequency information of the Fourier data having highest amplitude and position of the periodical groups by a phase information of the harmonic frequency.

7. Method according to claim 6, comprising further a step of deducting positions of spokes and deriving respective spoke widths in the identified periodical patterns and generating a spoke configuration map representing the spoke configuration data of the wheel.

8. Method according to one of the preceding claim, comprising further a step of determining an optimal value and optimal position of a balancing weight for the wheel.

9. Method according to claim 8, comprising further a step of comparing the optimal position of the balancing weight and the spoke configuration data whether the optimal position of the balancing weight already matches with a position of a spoke.

10. Method according to claim 9, comprising further a step of determining a first and a second spoke in the spoke configuration data adjacent to the optimal position of the balancing weight, if the outcome of the comparing step is such that the determined optimal position of the balancing weight is not or partially not behind a spoke.

11. Method according to claim 10, comprising further a splitting step with calculating a first and second split value of a first and second split balancing weight based on the determined value and position of the optimal balancing weight and the positions of the first spoke and the second spoke.

12. Method according to claim 11, wherein the splitting step is iterated until a predetermined dimension for a split balancing weight is reached or until a determined dimension for a split balancing weight is smaller as a width of a respective determined spoke according to the spoke configuration data.

13. Method according to claim 12, wherein iteration of the splitting step comprises the step of setting at least one of the determined positions of the first spoke and the second spoke with the respective calculated value for the split balancing weight as respective new starting conditions for a next splitting step.

14. Computer program product comprising code means for carrying out the steps of one of the methods according to claims 1 to 13, when the code means run on a computer controlling a wheel balancing apparatus.

15. Data storage means comprising the computer program product according to claim 14 stored thereon.

16. Apparatus for balancing a vehicle wheel and placing required balancing weight behind spokes of a wheel to be balanced, the apparatus comprising: a measurement shaft attached to a balancing machine;mounting means for mounting the vehicle wheel to the shaft for rotation about a wheel axis;a light source operable to direct an emitted light beam onto a location on the vehicle wheel;a light-sensitive receiver operable to receive a beam reflected by the sensed location on the vehicle wheel;means for moving the light source and the receiver synchronously;means for storing measurement values of the position sensitive receiver;transformation means for performing a transformation on the stored measurement values from the spatial domain into the frequency domain; andan electronic evaluation system configured to evaluate the transformed spokes data and generating spoke configuration data representing the positions and characteristics of the spokes and the spaces between consecutive spokes of the wheel.

17. Apparatus according to claim 15, further comprising a force measuring device operable to supply signals proportional to an unbalance of the vehicle wheel to the evaluation system; andwherein the evaluation system is configured to evaluate the values for balancing the vehicle wheel and the values of the spoke configuration data for providing positions for balancing weights, which are on the rim behind a spoke of the wheel.

18. Apparatus according to claim 16 or 17, wherein the light source and the receiver are synchronously moveable for scanning spokes data in several predetermined positions.

19. Apparatus according to one of the claims 16 to 18, wherein the transformation means are a processing unit configured to perform a Fourier Transform.

20. Apparatus according to one of the claims 16 to 18, wherein the transformation means are a digital signal processor configured to perform a fast Fourier Transform.