Method for manufacturing a torque converter with a laser-cut periodic pattern of an adhesive surface

Abstract

Method for manufacturing a torque converter (100, 200), the method comprising: forming a turbine housing (118, 218) containing a first annular section (118A, 218A), wherein the first annular section contains: a first surface (120, 220) having a first roughness; and forms a radially outermost section of the turbine casing (118, 218); firmly connecting a first plurality of blades (122, 222) to the turbine casing (118, 218); forming an impeller casing (112, 212) containing a second annular section (112A, 212A) with a second surface (114, 214) having a second roughness; firmly connecting a second plurality of blades (116, 216) to the impeller casing (112, 212); removing at least part of the first (120, 220) or the second (114, 214) surface without the use of solid particles or a liquid;Increasing the first or second roughness of the first (120, 220) or second (114, 214) surface from which at least one part has been removed; applying an adhesive to the first or second surface from which at least one part has been removed;and the application of a friction material by means of the adhesive to the first or the second surface from which the at least one part has been removed, wherein the removal of the at least one part includes the formation of a periodic pattern (130) in the first or the second surface from which the at least one part has been removed, wherein a laser removes at least a part of the material in question from which the first or second surface is formed in order to generate the periodic pattern (130), characterized in that the laser is moved in figure-eight serpentine lines in the X and Y directions while being guided in the X or Y direction over the first (120, 220) or second (114, 214) surface.

Description

TECHNICAL AREA The foregoing disclosure relates to a method for roughening a surface of a coupling to which a friction material is bonded, for a torque converter, and to a torque converter comprising a coupling with a roughened surface to which the friction material is bonded. BACKGROUND OF THE INVENTION Fig. 5 is a partial cross-sectional view of a known torque converter 300 with a turbine coupling 302. The torque converter 300 includes a cover 304 for receiving torque, an impeller 306, a turbine 308, and a stator 310. The impeller 306 comprises an impeller housing 312 with a section 312A having a surface 314, and blades 316, which are rigidly connected to the housing 312, for example, by brazing. The turbine 308 comprises a turbine housing 318 with a radially outermost section 318A having a surface 320, and blades 322, which are rigidly connected to the housing 318, for example, by brazing. The stator 310 contains blades 324 and a freewheel clutch 325. The clutch 302 contains a friction material 326, which is bonded to one of the surfaces 314 or 320 by means of an adhesive. The clutch 302 acts as a bypass clutch for the torque converter 300.For example, the housing 318 is displaced axially in the direction AD by pressure in the chamber 328 to bring the friction material 326 into contact with the surfaces 314 and 320, thus connecting the housings 312 and 318 in a rotationally fixed manner. A torque transmitted to the housing 312 is therefore directly transferred to the housing 318. To bond the friction material to surface 314 or 320, the surface is roughened to facilitate adhesion. Typically, the blades 316 and 322 are attached to the housings 312 and 318, respectively, by a brazing process in which the blades and housings are heated. This heating process causes surfaces 314 and 320 to warp. Surfaces 314 and 320 are then machined to remove this warping. Because of the machining process, roughening can only be performed after brazing. Machining performed before brazing would negate the roughening. It is known to roughen surfaces such as surfaces 314 and 320 by sandblasting, for example with aluminum oxide particles. After sandblasting, the sandblasted parts must be washed to remove any particles remaining after the sandblasting process. The connection between the housing 312 and the blades 316, and between the housing 318 and the blades 322, creates a multitude of angles, crevices, pockets, and other shapes where particles can become trapped. It is very difficult, if not impossible, to remove these particles by washing or other means. Particles remaining in the turbine or impeller can adversely affect the function of the torque converter 300 or other components connected to the torque converter, such as a gear pump that supplies fluid to the torque converter. In DE 196 26 685 A1 and DE 10 2013 202 661 A1, torque converters and methods for their manufacture are described. DE 199 38 711 C1 discloses a method for manufacturing a carrier plate for a brake or clutch lining, wherein blind holes are created in the carrier plate by means of a laser, which are inclined against the intended load direction and improve the load-bearing capacity, in particular against shear forces. It is also proposed to arrange the blind holes in offset rows. DE 100 35 489 A1 discloses a method for manufacturing a carrier plate for a friction lining, wherein, as an alternative to brushing the surface of the carrier plate, structuring by means of laser treatment is provided to improve the adhesion of the friction lining to the carrier plate. The object of the present invention is to further improve the adhesion of the friction lining to the carrier plate. This problem is solved by a method having the features according to claim 1. SUMMARY According to the aspects illustrated herein, a method for manufacturing a torque converter is provided, comprising: forming a turbine casing containing a first annular section, the first annular section containing a first surface having a first roughness and forming a radially outermost section of the turbine casing; firmly joining a first plurality of blades to the turbine casing; forming an impeller casing containing a second annular section with a second surface having a second roughness; firmly joining a second plurality of blades to the impeller casing; removing at least a portion of the first or the second surface without the use of any particular substance or liquid; increasing the first or the second roughness of the first or the second surface from which at least a portion has been removed;Applying an adhesive to the first or second surface from which at least one part has been removed; and adhering a friction material to the first or second surface from which at least one part has been removed using the adhesive. According to the aspects illustrated herein, a method for manufacturing a torque converter is provided, the method comprising: forming a turbine casing containing an annular section, the annular section comprising a first surface having a first roughness and forming a radially outermost section of the turbine casing; firmly joining a first plurality of blades to the turbine casing; forming an impeller casing containing a second annular section with a second surface having a second roughness; firmly joining a second plurality of blades to the impeller casing; bombarding the first or the second surface with particles of solid carbon dioxide or with particles of NaHCO3; applying an adhesive to the bombarded first or second surface; and bonding the friction material to the bombarded first or second surface by means of the adhesive. According to the aspects illustrated herein, a torque converter is provided, comprising: a cover for receiving torque; an impeller comprising an impeller housing and a first surface rigidly connected to the cover; a first plurality of blades rigidly connected to the impeller housing; a turbine comprising a turbine housing with a second surface forming a radially outermost section of the turbine housing; a friction material bonded to the first or second surface by means of an adhesive; and a stator connected to the turbine and impeller, comprising a third plurality of blades. The first or second surface to which the friction material is bonded has a periodic pattern etched into it. BRIEF DESCRIPTION OF THE DRAWINGS Various embodiments are disclosed by way of example only with reference to the accompanying schematic drawings, in which certain reference symbols denote corresponding parts, wherein: Fig. 1A is a perspective view of a cylindrical coordinate system illustrating the spatial concepts used in this patent specification; Fig. 1B is a perspective view of an object in the cylindrical coordinate system of Fig. 1A illustrating the spatial concepts used in this patent specification; Fig. 2 is a partial cross-sectional view of a torque converter incorporating a turbine coupling with a roughened surface to which the friction material is bonded; Fig. 3 is an axial view of a surface in region 3 of Fig. 2, showing a schematic representation of an exemplary pattern etched into the surface; Fig.Figure 4 is a partial cross-sectional view of a torque converter incorporating a turbine coupling with a roughened surface to which the friction material is bonded; and Figure 5 is a partial cross-sectional view of a known torque converter with a turbine coupling. DETAILED DESCRIPTION It should be obvious from the outset that identical drawing numbers in different drawing views denote identical or functionally similar structural elements of the disclosure. It should be clear that the claimed disclosure is not limited to the disclosed aspects. Furthermore, it is clear that this disclosure is not limited to the individual processes, materials, and modifications described and may therefore naturally vary. It is also clear that the terms used herein serve only to describe individual aspects and are not intended to restrict the scope of protection afforded by this disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as they would be understood by a person skilled in the art to whom this disclosure is addressed. It should be clear that any methods, units, or materials similar to or equivalent to those described herein may be used to implement or test the disclosure. Fig. 1A is a perspective view of a cylindrical coordinate system 10, illustrating the spatial concepts used in this patent specification. The present invention is described, at least in part, in connection with the cylindrical coordinate system 10. The system 10 has a longitudinal axis 1, which serves as a reference for the following spatial and directional concepts. An axial direction AD is parallel to the axis 1. A radial direction RD is perpendicular to the axis 1. A circumferential direction CD is defined by an endpoint of a radius R (perpendicular to the axis 1) that rotates about the axis 1. Objects 4, 5, and 6 serve to illustrate spatial concepts. Surface 7 of object 4 forms an axial plane. For example, axis 1 is congruent with surface 7. Surface 8 of object 5 forms a radial plane. For example, radius 2 is congruent with surface 8. Surface 9 of object 6 forms a circumferential surface. For example, circumference 3 is congruent with surface 9. Another example states that axial movement or position occurs parallel to axis 1, radial movement or position occurs perpendicular to axis 2, and circumferential movement or position occurs parallel to circumference 3. Rotation is described here with reference to axis 1. The terms "axial", "radial" and "circumferential" refer to an alignment parallel to axis 1, radius 2 and circumference 3 respectively. The terms "axial", "radial" and "circumferential" also refer to an alignment parallel to corresponding planes. Fig. 1B is a perspective view of an object 15 in the cylindrical coordinate system 10 of Fig. 1A, which illustrates the spatial concepts used in the present patent specification. The object 15 is representative of a cylindrical object in a cylindrical coordinate system and is not intended to limit the claims of the present invention in any way. The object 15 comprises an axial surface 11, a radial surface 12, and a circumferential surface 13. The surface 11 is part of an axial plane, the surface 12 is part of a radial plane, and the surface 13 is part of a circumferential surface. Fig. 2 is a partial cross-sectional view of a torque converter 100, which includes a turbine coupling 102 with a roughened surface to which a friction material is bonded. The torque converter 100 includes a cover 104 for receiving torque (for example, from a [not shown] motor), an impeller 106, a turbine 108, and a stator 110. The impeller 106 includes an impeller housing 112 with an annular section 112A containing a surface 114, and blades 116 attached to the housing 112. The turbine 108 comprises a turbine housing 118 with a radially outermost section 118A containing surface 120, and blades 122 that are rigidly connected to the housing 118. The stator 110 comprises blades 124 and a freewheel clutch 125. The clutch 102 comprises a friction material 126 that is bonded to one of the surfaces 114 or 120 by means of an adhesive. The clutch 102 serves as a bypass clutch for the torque converter 100.For example, the housing 118 is displaced axially in the direction AD by pressure in the chamber 128 to bring the friction material 126 into contact with the surfaces 114 and 120, thus connecting the housings 112 and 118 in a rotationally fixed manner. A torque transmitted to the housing 112 is therefore directly transferred to the housing 118. To adhere the friction material to surface 114 or 120, the surface is roughened to facilitate bonding. Typically, the blades 116 and 122 are attached to the housings 112 and 118, respectively, by a brazing process in which the blades and housings are heated. This heating process causes surfaces 114 and 120 to warp. Surfaces 114 and 120 are then machined to remove this warping. Because of the machining process, roughening can only be performed after brazing. Machining performed before brazing would negate the roughening. Fig. 3 is an axial view of surface 120 in region 3 of Fig. 2, showing a schematic representation of an exemplary pattern 130 etched into surface 120. Although surface 120 is shown in Fig. 3, it should be clear that surface 114 can also contain a pattern 130 etched into it. It should be clear that pattern 130 is a schematic example and that other patterns are possible. The structuring process is discussed below. The following describes an exemplary method for forming the torque converter 100. For clarity, the method is presented as a sequence of steps; however, no specific order should be inferred from this sequence unless explicitly stated otherwise. In a first step, the impeller housing 112 is formed, which contains the annular section 112A. Section 112A contains the surface 114, which has a first roughness. In a second step, the blades 116 are attached to the impeller housing. In a third step, the turbine housing 118 and the annular section 118A are formed. Section 118A contains the surface 120. The surface 120 has a second roughness. In a fourth step, the blades 122 are firmly connected to the turbine housing 118. In a fifth step, at least a portion of the surface 114 or 120 is removed without the use of solid particles or a liquid.The following description refers to surface 120; however, it should be clear that the description is equally applicable to surface 114. In a sixth step, the roughness of surface 120 is increased. In a seventh step, an adhesive is applied to surface 120. In an eighth step, a friction material 126 is bonded to surface 120 using the adhesive. Removing at least part of surface 114 or 120 involves forming a periodic pattern 130 in surface 120. According to an exemplary embodiment, firmly joining the blades 116 to the impeller casing involves applying solder to the impeller casing and / or the blades 116 and heating the impeller casing, the solder, and the blades 116. According to an exemplary embodiment, surface 114 is machined in a ninth step prior to the fifth step to achieve the second roughness. According to an exemplary embodiment, firmly joining the blades 122 to the turbine casing involves applying solder to the turbine casing and / or the blades 122 and heating the turbine casing, the solder, and the blades 122.According to an exemplary embodiment, the surface 120 is machined in a tenth step before the fifth step in order to achieve the first roughness. In an eleventh step, the turbine and the impeller are assembled with the stator 110. In a twelfth step, the impeller housing 112 is firmly connected to the cover 104. According to an exemplary embodiment, a laser is used in the fifth step. The laser power and the duration for which the laser is focused on a specific area of ​​the surface 114 or 120 are selected such that the laser removes at least a portion of the material from which the surfaces 114 and 120 are formed, in order to create the pattern 130. According to an exemplary embodiment, the laser is moved in figure-eight serpentine patterns in the X and Y directions while being guided across the surface 114 or 120 in the X or Y direction. An advantage is that using a laser to etch the surface 114 or 120 does not result in contamination of the torque converter 100 with particles, for example, because the laser essentially vaporizes the removed material and the vaporized material can be extracted from the surface 114 or 120. Fig. 4 is a partial cross-sectional view of a torque converter 200 which includes a turbine coupling 202 with a roughened surface to which a friction material is glued. The torque converter 200 comprises a cover 204 for receiving torque (for example, from a [not shown] motor), an impeller 206, a turbine 208, and a stator 210. The impeller 206 comprises an impeller housing 212 with an annular section 212A containing a surface 214, and blades 216 fixedly connected to the housing 212. The turbine 208 comprises a turbine housing 218 with a radially outermost section 218A having a surface 220 and blades 222 fixedly connected to the housing 218. The stator 210 comprises blades 224 and a freewheel clutch 225. The clutch 202 comprises a friction material 226, which is bonded to one of the surfaces 214 or 220 by means of an adhesive. The clutch 202 acts as a bypass clutch for the torque converter 200.For example, the housing 218 is displaced axially in the direction AD by pressure in the chamber 228 to bring the friction material 226 into contact with the surfaces 214 and 220, thus connecting the housings 212 and 218 in a rotationally fixed manner. A torque transmitted to the housing 212 is therefore directly transferred to the housing 218. To bond the friction material to surface 214 or 220, the surface is roughened to facilitate adhesion. Typically, the blades 216 and 222 are attached to the housings 212 and 218, respectively, by a brazing process in which the blades and housings are heated. This heating process causes surfaces 214 and 220 to warp. Surfaces 214 and 220 are then machined to remove this warping. Because of the machining process, roughening can only be performed after brazing. Machining performed before brazing would negate the roughening. The following describes a method for manufacturing the torque converter 200. For clarity, the method is presented as a sequence of steps; however, no order should be inferred from this sequence unless explicitly stated. In a first step, the impeller housing 212, which contains the annular section 212A, is formed. In a second step, the blades 216 are rigidly connected to the impeller housing. In a third step, the turbine housing 218 and the annular section 218A are formed. Section 218A contains the surface 220. In a fourth step, the blades 222 are rigidly connected to the turbine housing 218. In a fifth step, the surface 214 or 220 is bombarded with particles of solid carbon dioxide or with particles of NaHCO3. In a sixth step, an adhesive is applied to the bombarded surface 214 or 220.In a seventh step, the friction material 226 is glued onto the surface 214 or 220 being shot at using the adhesive. When surface 214 is bombarded with NaHCO3 particles, the impeller casing and blades 216 are washed to remove any remaining NaHCO3 particles from or on the impeller casing or blades 216 after bombardment. When surface 220 is bombarded with NaHCO3 particles, the turbine casing and blades 222 are washed to remove any remaining NaHCO3 particles from or on the turbine casing or blades 222 after bombardment. According to an exemplary embodiment, the fixed connection of the blades 216 to the impeller housing involves applying a solder to the impeller housing and / or the blades 216 and heating the impeller housing, the solder, and the blades 216. According to an exemplary embodiment, the surface 214 is machined in a ninth step before the fifth step. According to an exemplary embodiment, the fixed connection of the blades 222 to the turbine housing involves applying a solder to the turbine housing and / or the blades 222 and heating the turbine housing, the solder, and the blades 222. According to an exemplary embodiment, the surface 220 is machined in a tenth step before the fifth step. In an eleventh step, the turbine and the impeller are assembled with the stator 210. In a twelfth step, the impeller housing 212 is firmly connected to the cover 204. One advantage is that all carbon dioxide particles remaining in the impeller 206 or the turbine 208 after the fifth step evaporate at room temperature. Therefore, no residues remain that could adversely affect the torque converter 200 or equipment connected to the torque converter 200. Since NaHCO3 is water-soluble, virtually all of the NaHCO3 remaining in the impeller 206 or turbine 208 after the fifth step can be advantageously removed in the washing process of the ninth and tenth steps. Therefore, no particles remain that could adversely affect the torque converter 200 or equipment connected to the torque converter 200. It is obvious that various features and functions disclosed above, as well as other features and functions or their alternatives, can be combined to suit many other different systems or applications. A person skilled in the art may later introduce various currently unforeseeable or unexpected alternatives, modifications, variants, or improvements, which are also intended to be covered by the following claims.

Claims

Method for manufacturing a torque converter (100, 200), the method comprising: forming a turbine housing (118, 218) containing a first annular section (118A, 218A), wherein the first annular section contains: a first surface (120, 220) having a first roughness; and forms a radially outermost section of the turbine casing (118, 218); firmly connecting a first plurality of blades (122, 222) to the turbine casing (118, 218); forming an impeller casing (112, 212) containing a second annular section (112A, 212A) with a second surface (114, 214) having a second roughness; firmly connecting a second plurality of blades (116, 216) to the impeller casing (112, 212); removing at least part of the first (120, 220) or the second (114, 214) surface without the use of solid particles or a liquid;Increasing the first or second roughness of the first (120, 220) or second (114, 214) surface from which at least one part has been removed; applying an adhesive to the first or second surface from which at least one part has been removed;and the application of a friction material by means of the adhesive to the first or the second surface from which the at least one part has been removed, wherein the removal of the at least one part includes forming a periodic pattern (130) in the first or the second surface from which the at least one part has been removed, wherein a laser removes at least a part of the material in question from which the first or second surface is formed in order to generate the periodic pattern (130), characterized in that the laser is moved in figure-eight serpentine lines in the X and Y directions while being guided in the X or Y direction over the first (120, 220) or second (114, 214) surface. Method according to claim 1, wherein: the fixed joining of the first plurality of blades (122, 222) to the turbine housing (118, 218) comprises: applying a solder to the turbine housing (118, 218) or the first plurality of blades (122, 222); and heating the turbine housing (118, 218), the solder and the first plurality of blades (122, 222). The method according to claim 2, further comprising, prior to the removal of at least one part of the first (120, 220) or the second surface (114, 214): machining the first surface to achieve the first roughness. Method according to claim 1, wherein: the fixed joining of the second plurality of blades (116, 216) to the impeller housing (112, 212) comprises: applying a solder to the impeller housing (112, 212) or the second plurality of blades (116, 216); and heating the impeller housing (112, 212), the solder and the second plurality of blades (116, 216). The method according to claim 4, further comprising, prior to the removal of at least one part of the first (120, 220) or the second (114, 214) surface: machining the second surface to achieve the second roughness. The method according to claim 1, further comprising: assembling the turbine (108, 208) and the impeller (106, 206) with a stator (110, 210) comprising a third plurality of blades (124, 224). Method according to claim 5, further comprising: firmly connecting the impeller housing (112, 212) to the cover (104, 204) of the torque converter (100, 200).

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