METHOD AND A MACHINE FOR BALANCING VEHICLE WHEELS

• US 20100005883A1
• Filed: 05/08/2007
• Published: 01/14/2010
• Est. Priority Date: 09/11/2006
• Status: Active Grant

• Current Assignee: Corghi SpA (Nexion S.p.A.)
• Original Assignee: Corghi SpA (Nexion S.p.A.)
• Inventors: Corghi, Remo
• Granted Patent: US 8,113,049 B2
• Time in Patent Office: Days
• US Class Current: 73/470
• CPC Class Codes: G01B 11/2522 the position of the object changing and being recorded
• CPC Class Codes: G01N 21/255 Details, e.g. use of specially adapted sources, lighting or optical systems
• CPC Class Codes: G01N 21/85 Investigating moving fluids or granular solids
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held
• CPC Class Codes: G01N 2201/0224 Pivoting casing
• CPC Class Codes: G01N 2201/0618 Halogene sources
• CPC Class Codes: G01N 2201/0692 Regulated sources; stabilised supply
• CPC Class Codes: G01N 2201/0694 Microprocessor controlled supply
• CPC Class Codes: G01N 2201/0696 Pulsed
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

A method and a machine for balancing vehicle wheels with weights (18), the method comprising stages of: using a video camera (5, 6, 206) to frame a portion of a surface of a hub (101) of a wheel on which a weight (18) is to be applied, locating, in images of the hub (101) taken by the camera (5, 6, 206), at least a balancing plane (E1, E2) which is perpendicular to a rotation axis (A) of the wheel, piloting at least a pick-up device (8, 9, 209) such as to direct the at least a pick-up device (8, 9, 209) onto a point (P1, P2) of the hub (101) belonging to the balancing plane (E1, E2), detecting, by means of the pick-up device (8, 9, 209) characteristic geometric parameters of the hub (101) at the balancing plane (E1, E2), measuring an imbalance of the wheel, calculating, by means of an electronic calculator (4, 204) an entity of at least a weight (18) to be applied to the hub (101) at the balancing plane (E1, E2), and also calculating an angular position (T1, T2) of the weight (18) in the balancing plane (E1, E2).

Claims

1-105. -105. (canceled)

106. A method for balancing vehicle wheels using weights (18), comprising stages of:

using a video camera (5, 6, 206) to frame a portion of a surface of a hub (101) of a wheel on which a weight (18) is to be applied;

locating, in images of the hub (101) taken by the camera (5, 6, 206), at least a balancing plane (E1, E2) which is perpendicular to a rotation axis (A) of the wheel,

piloting at least a pick-up device (8, 9, 209) such as to direct the at least a pick-up device (8, 9, 209) onto a point (P1, P2) of the hub (101) which belongs to the balancing plane (E1, E2), detecting, by means of the pick-up device (8, 9, 209) characteristic geometric parameters of the hub (101) at the balancing plane (E1, E2),

measuring an imbalance of the wheel,

calculating, by means of an electronic calculator (4, 204), an entity of at least a weight (18) to be applied to the hub (101) at the balancing plane (E1, E2), and an angular position (T1, T2) of the weight (18) in the balancing plane (E1, E2),

characterised in that the stage of locating the balancing plane (E1, E2) includes;

identifying, in the images of the hub (101) taken by the camera (206), at least a reference line (C) corresponding to a circumference of the surface of the hub (101).

107. The method of claim 106, characterised in that identification of the reference line (C) comprises the electronic calculator (204) acquiring at least an image of the hub (101) taken by the camera (206), and subjecting the image to an analytical processing for recognising the predetermined reference line (C) in the image.

108. The method of claim 106, characterised in that the predetermined reference line (C) corresponds to a rim (109) edge of the hub (101).

109. The method of claim 107, characterised in that the analytical processing of the image is aimed at recognising the transition zone between the hub (101) and the tyre (104) in the image.

110. The method of claim 107, characterised in that the image is acquired in a condition in which a portion of the hub (101) taken by the camera (209) is illustrated by at least a light.

111. The method of claim 106, characterised in that the stage of locating the balancing plane (E1, E2) further comprises:

establishing a distance (L1, L3) between the balancing plane (E1, E2) and the circumference of the hub (101) which is represented by the reference line (C) identified on the images.

112. The method of claim 106, characterised in that the stage of piloting the pickup device (209) includes displacing the pick-up device (209) up until it is directed onto a point of the hub (101) which belongs to the circumference represented by the reference line (C) identified on the images.

113. The method of claim 112, characterised in that the pick-up device (209) generates a light trace on the surfaces of the hub (101) onto which it is directed, and that the displacement of the pick-up device (209) proceeds up until the projection (230) of the light trace on the images is at the reference line (C).

114. The method of claim 113, characterised in that the displacement of the pick-up device (209) is controlled by the electronic calculator (204), which processes the images taken by the camera (206) in order to detect, in a predetermined two-dimensional reference system (xy) of the images, the position of the projection of the light tract generated by the pick-up device (209) and the identified reference line (C).

115. The method of claim 111, characterised in that the stage of piloting the pick-up device (209) includes further displacing the pick-up device (209) in a parallel direction to the axis A of the wheel (100), by a quantity equal to the distance (L1, L3) established between the balancing plane (E1, E2) and the circumference of the hub (101) which is represented by the reference line (C) identified by the images.

116. The method of claim 106, characterised in that the stage of locating the balancing plane (E1, E2) includes:

identifying, in the images of the wheel taken by the camera (206), a plurality of reference lines (C4-C7), each of which represents a circumference belonging to a predetermined annular strip of the wheel (100);

displacing the pick-up device (209) in order to direct it onto a plurality of points on the wheel (100), each of which belongs to one of the circumferences in the annular strip of the wheel (100) and which points are singly represented by the reference lines (C4-C7) identified on the images,

measuring the characteristic parameters of the hub (101) in the said points by means of the pick-up device (209).

117. A method for balancing vehicle wheels using weights (18), comprising stages of:

using a video camera (5, 6, 206) to frame a portion of a surface of a hub (101) of a wheel on which a weight (18) is to be applied;

locating, in images of the hub (101) taken by the camera (5, 6, 206), at least a balancing plane (E1, E2) which is perpendicular to a rotation axis (A) of the wheel,

piloting at least a pick-up device (8, 9, 209) such as to direct the at least a pick-up device (8, 9, 209) onto a point (P1, P2) of the hub (101) which belongs to the balancing plane (E1, E2), detecting, by means of the pick-up device (8, 9, 209) characteristic geometric parameters of the hub (101) at the balancing plane (E1, E2),

measuring an imbalance of the wheel,

calculating, by means of an electronic calculator (4, 204), an entity of at least a weight (18) to be applied to the hub (101) at the balancing plane (E1, E2), and an angular position (T1, T2) of the weight (18) in the balancing plane (E1, E2),

characterised in that the stage of locating the balancing plane (E1, E2) includes;

projecting the images taken by the at least a camera (5, 6) on a screen (7), and

arbitrarily selecting the balancing plane (E1, E2) from the images projected on the screen (7).

118. The method of claim 117, characterised in that the piloting of the pick-up device (8, 9) includes the pick-up device (8, 9) generating a light trace (200) on the surfaces of the hub (101) onto which the pick-up device (8, 9) is directed, and in that the pick-up device (8, 9) is displaced up until the projection (20) of the light trace (200) on the images is located at the pre-selected balancing plane (E1, E2).

119. The method of claim 118, characterised in that the displacement of the pick-up device (8, 9) is controlled by a manual selector (14) activated directly by an operative, which operative, via the screen (7), observes movement of the projection (20) of the light trace (200) in the images.

120. The method of claim 118, characterised in that the displacement of the pick-up device (8, 9) is controlled by the electronic calculator (4), which processes the images taken by the camera (5, 6) in order to detect, in a predetermined two-dimensional reference system (xy) which is fixed with respect to the images, a position of the projection (20) of the light trace (200) and the projection (E1′

, E2′

) of the pre-selected balancing plane (E1, E2).

121. The method of claim 117, characterised in that the images taken by the camera (5, 6) are processed by the electronic calculator (4), which calculator (4) is programmed to enable selection of the points (P1′

, P2′

) in the images, and in that selection of the balancing plane (E1, E2) is done by selecting a point (P1′

, P2′

) in the images at the first pre-selected balancing plane (E1, E2).

122. The method of claim 118, characterised in that the images taken by the camera (5, 6) are processed by the electronic calculator (4), which is programmed to perform stages of:

memorising a base image of the wheel surfaces taken by the camera (5, 6),

moving the pick-up device (8, 9) such that the light trace (200) displaces on the surfaces taken by the camera (5, 6) along a predetermined trajectory,

detecting, in a predetermined two-dimensional system (xy) of the images, coordinates of the projection (20) of the light trace (200) in a plurality of distinct positions along the trajectory,

memorising the spatial position of the pick-up device (8, 9) at each position in which detection of the position of the projection (20) of the light trace (200) is made,

projecting the base image onto the screen (7) and signalling thereon the points at which the instantaneous coordinates have previously been detected.

123. The method of claim 122, characterised in that the stage of choosing the balancing plane (E1, E2) is done by selecting, from among the points signalled on the base image, a point which is located at the pre-selected balancing plane (E1, E2).

124. The method of claim 123, characterised in that the stage of positioning the pick-up device (8, 9) includes:

arranging the pick-up device (8,9) in the memorised spatial position in which the projection (20) of the light trace (200) is at the selected point on the base image.

125. A machine for balancing vehicle wheels using weights (18), comprising a rotating shaft (3, 203) which rotates on a fixed structure (2, 202), means for blocking the wheel on the rotating shaft (3, 203), means for measuring an imbalance of the wheel, an electronic calculator (4, 204) for calculating entities of the weights (18) to be applied to a hub (101) of the wheel (100) in at least a preselected balancing plane (E1, E2) which is perpendicular to the axis (A) of the wheel and the angular position of the weights (18) in the balancing plane (E1, E2), at least a camera (5, 6, 206) for framing a portion of the hub (101) in which weights (18) are to be applied, a screen (7, 207B) on which images taken by the camera (5, 6206) are projected, and at least a pick-up device (8, 9, 209), connected to the electronic calculator (4, 204), which is destined to be piloted in order to be directed on to a point (P1, P2) on the hub (101) which belongs to the balancing plane (E1, E2), characterised in that it comprises means for acquiring a plurality of distinct photographs of the hub (101), in a predetermined temporal order and under different conditions in order to identify at least a reference line (C) corresponding to a circumference of the surface of the hub (101).

126. The machine of claim 125, characterised in that the pick-up device (8, 9, 209) is an optical device for measuring distances which comprises means for detecting a position of a point on the hub (101) in relation to a preselected known reference system (XYZ).

127. The machine of claim 125, characterised in that the pick-up device (8, 9, 209) is associated to means for activating (12, 13, 213) for moving the pick-up device (8, 9, 209) with respect to the balancing machine.

128. The machine of claim 127, characterised in that the pick-up device (8, 9, 209) generates a light trace (200) on the surface of the hub (101), at the measuring point.

129. The machine of claim 127, characterised in that the means for activating (12, 13) are commanded by a manual selector (14) which is directly activated by an operative.

130. The machine of claim 128, characterised in that the camera (5, 6, 206) is connected to the electronic calculator (4, 204), which comprises a program for processing and projecting the images on the screen (7, 207B), and is connected to the means for activating (12, 13, 213) of the pick-up device (8, 9, 209).

131. The machine of claim 128, characterised in that the electronic calculator (4, 204) comprises a program for detecting a position on the images of the projection (20, 230) of the light trace (200) of the pick-up device (8, 9, 209), with respect to a two-dimensional reference system (xy) which is fixed with respect to the images, and for commanding the means for activating the pick-up device (8, 9, 209) in order to position the projection (20, 230) of the light trace (200) in a position on the images.

132. The machine of claim 131, characterised in that it comprises means, connected to the electronic calculator (4), for selecting a point (P1′

, P2′

) in the images projected on the screen (7), and in that the electronic calculator (4) comprises a program for detecting a position of the point (P1′

, P2′

) with respect to the two-dimensional reference system (xy) of the images.

133. The machine of claim 132, characterised in that the means for selecting a point (P1′

, P2′

) comprise a touchscreen monitor, which also functions as a monitor screen (7).

134. The machine of claim 125, characterised in that it comprises at least a lighting device (210) arranged in order to illuminate a portion of the hub (101) surface framed by the camera (206).