TIE ROD END

Abstract: A tie rod end (16) has a one-piece stamped sheet metal housing (40) for connecting a tie rod and a ball stud (30). The sheet metal housing includes a tie rod receiving portion (42) with a longitudinally extending chamber for receiving an end portion of a tie rod; a socket portion (44) which encloses a ball stud and an elastomeric bearing therebetween; and a connector section (46) extending between the tie rod receiving portion and the socket portion. The sheet metal housing is made by starting with a single flat piece of sheet metal which is formed, using progressive dies, into its final shape. The sheet metal element has only one seam thereon, which extends throughout the tie rod receiving portion and connector portion and through a part only of the socket portion. The single piece of sheet metal encircles the ball stud and bearing and completely defines an opening through which a shank of the ball stud projects.

Description: The present invention relates to a new and improved vehicle steering linkage element which comprises a tie rod end for use in connecting a tie rod with a steerable wheel of a vehicle. A tie rod end generally includes a housing having (i) a socket portion for receiving a ball stud and (ii) a tie rod receiving portion for receiving a tie rod. The housings of tie rod ends have been forged, cast, or stamped metal elements. US-A-4,235,558 shows a tie rod end having an elastomeric bearing adhesively bonded to a ball stud. The bearing and ball stud are inserted into a one-piece forged housing. The ball stud extends from an opening in a socket portion of the housing. The material adjacent the opening of the socket portion is deformed to retain the bearing and stud within the socket portion. US-A-2,910,316 shows a tie rod end having a stamped housing. The housing has an opening which is closed by a separate plate element to define a socket for a ball stud. US-A-2,274,420 shows a knuckle joint housing having a hollow shank portion. A separate tail piece cooperates with the joint housing to define a socket in which a rubber bearing and a ball stud are disposed. The use of forgings or castings for the housing of a tie rod end requires heavy manufacturing processes and results in a relatively heavy product. The sheet metal housings for tie rod ends shown in the art, though avoiding these problems, require at least two separate elements to completely define the socket portion of the housing which retains the ball stud. Another tie rod end is disclosed in GB-A-592 326. A ball stud has a head end and a shank which extends from the head end. A resilient bearing surrounds the head end of the ball stud. A one-piece stamped sheet metal housing has a socket portion and a tie rod receiving portion. The socket portion defines a chamber which contains the bearing and the head end of the ball stud. The tie rod receiving portion defines a second chamber for receiving the end of the tie rod which is secured in the second chamber. The end of the tie rod abuts an adjacent face of the resilient bearing. When the bearing is compressed within the first chamber, it will tend to buldge in the direction of the tie rod end, and deformation of the bearing will depend on the axial position of the tie rod end. The present invention proceeds from the prior art represented by GB-A-592 326 and provides a vehicle steering linkage element wherein the bearing receiving chamber is closed by a crimped portion of the sheet metal housing so that the bearing is received in the first chamber of the housing in a compressed state. More specifically, according to the present invention, the one-piece stamped metal housing has a connector portion interconnecting the socket portion and the tie rod receiving portion, and has a crimped portion closing the first chamber adjacent to the connector portion of the housing. Further embodiments of the invention are defined in the dependent claims. A one-piece stamped sheet metal housing for a tie rod end which comprises a crimped portion is already shown in GB-A-343 297. However, the crimped portion wherein the head end of the ball stud is received and the head end of the ball stud is not surrounded by an elastomeric bearing. Further features of the present invention will become apparent to those skilled in the art to which the present invention relates from reading the following specification with reference to the accompanying drawings, in which: Fig. 1 is a schematic perspective view of a linkage used in a vehicle steering mechanism and having a pair of tie rod ends constructed in accordance with the present invention; Fig. 2 is an enlarged view, partly in section, illustrating one of the tie rod ends of Fig. 1; Fig. 3 is an enlarged plan view of the tie rod end of Fig. 2; Fig. 4 is an enlarged view, partly in section, illustrating another embodiment of a tie rod end of the present invention; Fig. 5 is an enlarged plan view of the tie rod end of Fig. 4; Fig. 6 is an enlarged view, partly in section, illustrating a tie rod end which is still another embodiment of the present invention; Fig. 7 is a sectional view of a portion of yet another embodiment of the present invention; and Fig. 8 is a view taken along the lines 8-8 of Fig. 7. Description of Preferred Embodiments The present invention is a tie rod end and may be embodied in various constructions. A tie rod end embodying the present invention may be used in a variety of applications. The present invention is shown in Fig. 1 as embodied in a portion of a vehicle steering linkage 12. The linkage 12 is used to turn the steerable wheels of the vehicle. The linkage 12 includes a pair of tie rod ends 16 constructed in accordance with the present invention. Each tie rod end 16 includes a ball and socket assembly 18 which is adapted to be connected to a front wheel spindle (not shown) of the vehicle. Each tie rod end 16 is connected to a tie rod 20 which is pivotally connected to an intermediate portion of a center link 22. The center link 22 is connected at one end to an idler arm 24 which is pivotally mounted on the vehicle frame (not shown). The opposite end of the center link 22 is connected to a pitman arm 26 which is connected to the output of the vehicle steering gear (not shown). Actuation of the steering gear causes turning movement of the steerable wheels through the linkage 12 in a known manner. Figs. 2 and 3 illustrate a tie rod end 16 constructed in accordance with the present invention. The tie rod end 16 includes a ball stud 30 having a shank portion 32 and a head end portion 34. Although head end portion 34 is shown as having a spherical shape, it may also have a hemispherical shape or any other suitable shape. The tie rod end 16 also preferably includes a suitable elastomeric bearing 36 bonded to the ball stud 30. The tie rod end 16 further includes a one-piece stamped sheet metal housing 40. The sheet metal housing 40 includes a longitudinally extending tie rod receiving portion 42; a ball stud receiving or socket portion 44; and a connector portion 46 extending between the tie rod receiving portion 42 and the socket portion 44. An end portion of the tie rod 20 is threadedly received in the longitudinally extending tie rod receiving portion 42. Tie rod 20 is externally threaded at 50, and the tie rod receiving portion 42 is complementally internally threaded at 52. Rotation of the tie rod 20 relative to the tie rod receiving portion 42 causes an axial displacement therebetween, thereby changing wheel alignment (toe) in a known manner. Clamping ears 54 on the housing 40 cooperate with a bolt 56 and nut 58 to clamp the tie rod 20 and the housing 40 together to prevent relative movement therebetween. The ball stud 30 is supported for pivotal movement in a chamber 45 defined by the socket portion 44. Socket portion 44 is made of sheet metal which is formed about the ball stud 30 and bearing material 36, causing the bearing 36 to conform to the shape of the chamber 45. The bearing material 36 is thus held in place relative to the socket portion 44 of the housing 40. Because of the resiliency of the elastomeric bearing material 36, ball stud 30 may rotate and pivot to a degree relative to the socket portion 44. The elasticity of the bearing material 36 biases ball stud 30 to its centered position shown in Fig. 2 when moved therefrom. The socket portion 44 includes an opening 60 through which the shank 32 of the ball stud 30 projects. The sheet metal material of the socket portion 44 may be folded over or deformed at the edge of opening 60 to secure the bearing material 36 in place. The opening 60, as shown in Fig. 3, has an oval shape, and thus the ball stud 30 is constrained to move in a plane parallel to the longitudinal axis of the tie rod receiving portion 42. Opening 60 may be of a different shape to allow for other degrees of movement of the ball stud 30 relative to the bearing 40. The opening 60 is small enough so that the ball stud 30 and bearing 36 are held within the socket portion 44. The connector section 46 of the housing 40 interconnects the tie rod receiving portion 42 with the socket portion 44. Connector portion 46 (Fig. 2) includes a chip cavity 62 and a chip window 64. Any extraneous metal chips formed during the formation of the housing 40 including the formation of the threads 50 on tie rod receiving portion 42, may come out of the housing 40 through the chip window 64. In accordance with the present invention, the housing 40, which includes the tie rod receiving portion 42, the ball stud receiving socket portion 44, and the connector portion 46, is a one piece stamped sheet metal element. The housing 40 has only one seam. As used herein, the term seam refers to a line of junction between two edges of material, and does not refer to a fold or crimp or overlapping of the material. The seam in the element 40 may have the two edges of material interconnected as by welding or otherwise, but the edges need not be so interconnected, and may simply abut or be located near each other. The seam 70 (Fig. 3) in element 40 is a single continuous seam which includes a seam portion 70a in the tie rod receiving portion 42; a seam portion 70d in the connector section; a side wall seam portion 70c; and an end wall seam portion 70b. The seam portions 70a, 70b, 70c, and 70d together form one continuous seam 70 extending throughout the length of the tie rod receiving portion 42 and the connector section 46, and through a part of the socket portion 44. The single seam 70 extends only to the opening 60 in the socket portion 44. The tie rod receiving portion 42 of the housing 40 includes rod wall means 80 (Fig. 3) engaging an end portion of the tie rod 20. The rod wall means 80 has a first minor side surface 84 which forms a first edge of the seam portion 70a disposed in the tie rod receiving portion 42. The rod wall means 80 also includes a second minor side surface 87 which forms a second edge of the seam portion 70a disposed in the tie rod receiving portion 42. The first and second minor side surfaces 84, 87, are disposed adjacent each other throughout the length of the tie rod receiving portion 42. The rod wall means 80 (Fig. 3) has a generally cylindrical portion 89 which extends between the first and second minor side surfaces 84, 87 to define the generally cylindrical chamber 43 which receives the end portion of the tie rod 20. The only seam on the tie rod receiving portion 42 is the seam portion 70a. The generally cylindrical portion 89 of the rod wall means 80 is free of seams. The socket portion 44 of the housing 40 includes a side wall 102 (Fig. 2) encircling the head end portion 34 of the ball stud 30 and the elastomeric bearing 36. The socket portion 44 also includes a first end wall 104 and a second end wall 110 opposed thereto. The first end wall 104 extends inwardly from a first end portion 106 of the side wall 102 toward a central axis 108 of the stud mounting chamber. The first end wall 104 of the socket portion 44 is free of seams. The second end wall 110 extends inwardly from a second end portion 112 of the side wall 102 toward the central axis 108 of the socket portion 44. The second end wall 110 defines the opening 60 in the socket portion 44 through which the central axis 108 of the stud mounting chamber extends. The second end wall 110 includes a first minor side surface 114 (Fig. 3) and a second minor side surface 116. The first minor side surface 114 forms a first edge of the seam portion 70b disposed in the second end wall 110 of the socket portion 44. The second minor side surface 116 forms a second edge of the seam portion 70b disposed in the second end wall 110 of the socket portion 44. The seam portion 70b of the seam 70 terminates at an edge 122 of the opening 60 in the second end wall 110 of the socket portion 44. The side wall 102 of the socket portion 44 has a first minor side surface 130 (Fig. 3) which is a continuation of the first minor side surface 114 of the second end wall 110. The side wall 102 also includes a second minor side surface 132 which is a continuation of the second minor side surface 116 of the second end wall 110. The first minor side surface 130 forms a first edge of the seam portion 70c disposed in the side wall 102 of the socket portion 44. The second minor side surface 132 forms a second edge of the seam portion 70c disposed in the side wall 102 of the socket portion 44. The side wall 102 of the socket portion 44, which encircles the ball stud 30 and bearing material 36, is free of seams other than the seam portion 70c. The connector section 46, which connects the tie rod receiving portion 42 with the socket portion 44, includes a connector wall 140 (Fig. 3) which is a continuation of the rod wall means 80 and of the side wall 102. The connector wall 140 includes a first minor side surface 142 which is a continuation of the first minor side surface 84 of the rod wall means 42, and of the first minor side surface 130 of the side wall 102. The connector wall 140 also includes a second minor side surface 144 which is a continuation of the second minor side surface 87 of the rod wall means 80, and of the second minor side surface 132 of the side wall 102. The first minor side surface 142 of the connector wall 140 forms a first edge of the seam portion 70d disposed in the connector section 46. The second minor side surface 144 of the connector wall 140 forms a second edge of the seam portion 70d disposed in the connector section 46. Seam portion 70d is the only seam in the connector section 46. Connector wall 140 is free of seams other than the seam portion 70d. The seam 70 (Fig. 3) on sheet metal element 40, which includes seam portions 70A, 70B, 70C and 70D, is preferably closed along its extent through the connector portion 46 and the socket portion 44. Thus, first minor side surface 114 abuts second minor side surface 116 on second end wall 110. First minor side surface 130 abuts second minor side surface 132 on side wall 102. Similarly, first minor side surface 142 abuts second minor side surface 144 on connector wall 140. The seam portion 70A in rod mounting section 42 is open. The one piece sheet metal element 40 has one edge surface thereon which extends from along the tie rod receiving section 42, along the connector portion 46, around the opening 60, back along the connector portion 46, and then back along the tie rod mounting section 42. The one continuous edge surface includes first minor side surfaces 84, 142, 130, and 114; edge 150 around opening 60; and second minor side surfaces 116, 132, 144, and 87. The socket portion 44 of element 40 may also include a second opening 172 (Fig. 2) for air relief upon formation of the portion 44 about the ball stud/bearing combination 34, 36, and also to further secure the elastomeric bearing material 36 within the stud mounting chamber 100. Opening 172 is not located on the seam 70. The side wall 102 and the first and second end walls 104 and 110, respectively, together form a socket which defines a chamber 45 having the ball stud 30 and the elastomeric bearing 36 mounted therein. The side wall 103 forms a first surface of the socket which encircles the head end portion 34 of the ball stud 30 and engages the bearing 36. The second end wall 110 and the first end wall 104, respectively, form second and third surfaces of the socket which engage opposite ends of the bearing 36 and hold it in the chamber. The one-piece sheet metal housing 40, from which are formed the side wall 102 and the first and second end walls 104, 110, thus has the first, second and third surfaces. As noted above, the one-piece sheet metal housing 40 also includes the tie rod receiving portion 42 and the connector portion 46. The socket portion 44 may be considered as being divided into four sections by first and second intersecting imaginary planes. The first plane 160 (Fig. 2) extends perpendicular to the axis 163 of the tie rod receiving chamber. The second plane 162 extends perpendicular to the first plane 160 and parallel to the axis 163 of the tie rod receiving chamber. The first and second intersecting planes 160 and 162 thereby divide the socket portion 44 into an upper outer section 164, a lower outer section 166, an upper inner section 168, and a lower inner section 170. (The terms upper, lower, inner, and outer are used herein for reference only with respect to the drawings, and are not intended in any to limit the scope of the invention disclosed herein.) The seam portions 70b and 70c, which together constitute that part of the single seam 70 which is disposed on the socket portion 44, are located in only one of the four sections, to wit, upper inner section 168 of the socket portion 44. The other three sections 164, 166, 170 are each free of seams. The particular section of the socket portion 44 in which the seam portion 70b, 70c is disposed is a section adjacent to or facing the tie rod 20, as opposed to one of the sections which are facing away from the tie rod. The sheet metal housing 40 may be made using progressive dies. A flat sheet metal blank of an appropriate shape is formed in a succession of different dies until it reaches a partially formed shape where it is ready to have the ball stud/bearing combination inserted therein. The bearing material 36 is in its free state larger than the size of the chamber 45 into which it is received. Thus, upon insertion of the ball stud/bearing into the partially formed housing 40, and formation of the socket portion 44 about the ball stud/bearing, the material of bearing 36 is deformed to its final shape in which it is compressed and held securely in socket portion 44 of housing 40. Housing 40 is crimped together at 65 to close socket portion 44. Figs. 4 and 5 illustrate a tie rod end 16' which is an alternative embodiment of the present invention. The embodiment shown in Figs. 4 and 5 differs from the embodiment shown in Figs. 2 and 3, in the location of the housing seam. Otherwise, the two embodiments are similar. In the embodiment shown in Figs. 4 and 5, the first opening 60', through which the shank portion 32' of ball stud 30' extends, is not located along the seam 70', whereas the second opening 172' is located at the termination of seam 70'. The embodiment shown in Figs. 4 and 5 has a stronger opening 60', since the edge of the opening 60' is continuous and not interrupted by any seam, the metal being continuous around opening 60'. In this embodiment, the opening 60' is formed, as by cutting into the material, prior to assembly of the ball stud 30' into the stud mounting section 44' . After the ball stud/bearing assembly is inserted into the stud mounting section 44, the material around opening 172' is folded over, for example, by flanging as in a stamping die. In the embodiment shown in Figs. 4 and 5, the housing 40' which receives the end portion of the tie rod and the ball stud 30' is, like the Fig. 1 embodiment, a one-piece stamped sheet metal element. Fig. 6 illustrates a tie rod end which is another embodiment of the present invention. The tie rod end illustrated in Fig. 6 is generally similar to the tie rod end illustrated in Figs. 1-5, with the exception that the socket portion of the tie rod end of Fig. 6 has a spherical shape. The socket portion 244 of the tie rod end 216 shown in Fig. 6 includes a first surface or side wall 201; a second surface or second end wall 210; and a third surface or first end wall 204. The first surface 201 encircles the head end portion 234 of the ball stud 230 and engages the elastomeric bearing 236. The second surface 210, and the third surface 204, engage opposite ends of the elastomeric bearing 36 and hold it in the chamber defined by socket 244. Second end wall 210 (Fig. 6) defines an opening 260 through which the shank portion 232 of ball stud 230 projects. The tie rod 216 may also include a second opening 272. The one-piece sheet metal element which forms the tie rod end 216 and which includes the socket portion 244, has one seam only. The seam (not shown) may extend to either the opening 260 through which the ball stud 230 projects as in the embodiment of Fig. 3, or it may extend to the second opening 272 as in the embodiment of Fig. 4. Figs. 7 and 8 illustrate still another embodiment of the present invention. In this embodiment a different clamp mechanism is used than is used in the embodiments of Figs. 1-6. In Fig. 7, the tie rod 20' is externally threaded at two spaced apart areas 52', 52". The threaded sections 52', 52" cooperate with a complementally internally threaded surface 50' on sheet metal housing 40' to provide for threaded engagement between tie rod 20' and sheet metal member 40'. An annular groove 21' is circumscribed about tie rod 20' between threaded sections 52', 52". Clamping bolt 56', which extends through clamping ears 54' on housing 40', is disposed within the groove 21' and thus is partially within the outer diameter 57' of tie rod 20'. Bolt 56' cooperates with nut 59' to clamp housing 40' about tie rod 20'. Thus, when housing 40' is clamped about tie rod 20', should the clamp mechanism fail, axial movement of tie rod 20' will be limited by either of a pair of shoulders 61' on tie rod 20' which would abut bolt 56'. Thus, tie rod 20' cannot come completely out of housing 40' unless bolt 56' is removed. The axial distance between the pair of shoulders 61' is designed to be sufficient to allow for proper setting of vehicle wheel alignment.

Claims: A vehicle steering linkage element comprising: a tie rod (20); a ball stud (30) having a head end (34) and a shank portion (32) extending from said head end (34) along an axis (108); an elastomeric bearing (36) bonded to said head end (34) of said ball stud (30); a one-piece stamped sheet metal housing (40) having a socket portion (44) and a tie rod receiving portion (42); said socket portion (44) of said housing (40) defining a first chamber (45) and having an opening (60) therein, said first chamber (45) containing said bearing (36) in a compressed state and said head end (34) of said ball stud (30), said shank portion (32) of said ball stud (30) projecting through said opening (60), said first chamber (45) being at least in part defined by a first surface of said socket portion (44) which encircles said head end (34) of said ball stud (30) and engages said bearing (36) and by second and third surfaces which engage opposite ends of said bearing (36) and hold said bearing (36) in said chamber (45); said tie rod receiving portion (42) of said housing (40) defining a second chamber (43) for receiving the end of the tie rod (20) and having means (50) for securing the end of the tie rod (20) in said second chamber (43); characterized in that said one-piece stamped sheet metal housing (40) has a connector portion (46) interconnecting said socket portion (44) and said tie rod receiving portion (42), said housing (40) being crimped together at a location (65) to close said first chamber (45) in said socket portion (44) adjacent to said connector portion (46). A linkage element as defined in claim 1 further characterized by said crimped portion (65) of said housing (40) having surfaces which extend transversely to said axis (108), said surfaces abutting each other along side surfaces (142, 144) to close said first chamber (45) adjacent to said connector portion (46) of said housing (40). A linkage element as defined in claim 1 further characterized by said portions (42, 44, 46) of said one-piece stamped sheet metal housing (40) being formed from a single flat piece of sheet metal. A linkage element as defined in claim 1 further characterized by said one-piece stamped sheet metal housing (40) having one continuous seam (70) extending partially on said socket portion (44) and extending throughout said tie rod receiving portion (42) and said connector portion (46), said portions (42, 44, 46) of said housing (40) being free of seams other than said one seam (70). A linkage element as defined in claim 4 further characterized by said one seam (70) extending on said socket portion (44) of said housing (40) from said connector portion (46) to an opening (60) in said socket portion (44), said shank (32) extending outward from said opening (60). A linkage element as defined in claim 5 further characterized by said one seam (70) being defined by a continuous edge surface of said housing (40), said edge surface extending along said tie rod receiving portion (42), along said connector portion (46), and along said socket portion (44) to said opening (60), said edge surface extending around said opening (60) along said socket portion (44) to said connector portion (46) and to said tie rod receiving portion (42). A linkage element as defined in claim 4 further characterized by said socket portion (44) of said housing (40) having an opening (60) through which said shank (32) extends, said opening (60) being spaced axially from the portions of said seam (70B, 70C) extending along said socket portion (44) of said housing (40). A linkage element as defined in claim 1 further characterized by the tie rod (20') having first and second threaded portions (52', 52") that are axially separated from each other by an annular peripheral groove (21') extending between respective facing shoulder surfaces (61'), and said means for securing the end of the tie rod (20') in said second chamber including a pair of clamping ears (54') on said tie rod receiving portion of said housing (40'), said clamping ears (54') having apertures for receiving a bolt (56') extending transversely through said groove (21').

Inventors: WOOD, RUEY E., JR
Applicants: TRW INC.
Application year: 1989
Main classification: F16C11
IPC codes: F16C11, B62D7