JP2013068236A - Method for manufacturing ball joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a ball joint which has preferable manufacturability and can provide appropriate rigidity and torque.SOLUTION: An intermediate body with a ball seat 17 mounted on the outer circumferential side of a spherical body to be a ball part 21 is arranged in a die. Molten material is fed into the dir to form a housing 16. Preferable manufacturability can be obtained as compared to such a case that a housing is formed separately to mount the intermediate body on it. The surrounding of the housing 16 is pressed to give an elastic strain to the ball seat 17 and, thereby, the appropriate rigidity and torque can be obtained.

Description

  The present invention relates to a method for manufacturing a ball joint including a synthetic resin bearing seat that is positioned between a ball portion and a ball receiving portion and holds the ball portion.

  2. Description of the Related Art Conventionally, a ball joint used for a suspension device of a vehicle such as an automobile has a ball stud having a ball portion and a stud portion that is a shaft portion protruding from the ball portion, and an inner chamber that is a ball receiving portion. A housing serving as a receiving member; and a ball seat being a synthetic resin bearing seat positioned between the ball portion and the inner chamber and rotatably holding the ball portion.

  Generally, such a ball joint is formed by forging a housing in advance, mounting a separate ball seat on the outer peripheral side of the ball portion and placing it in the inner chamber of the housing, and then crimping the housing to deform the ball portion and It is manufactured by retaining the ball seat from the housing.

  However, in the case of such a manufacturing method, since each process, such as forging molding of a housing, arrangement | positioning of a ball sheet and a ball | bowl part, and these ball | bowl part and a ball | bowl sheet, is needed separately, manufacturability is not necessarily required. Not good.

  Therefore, a method is known in which an intermediate body in which a separate ball seat is mounted on the outer peripheral side of a spherical body to be a ball portion is placed in a mold, and a molten metal such as an aluminum alloy is poured into the mold to die cast the housing. (For example, see Patent Document 1).

JP 2010-185520 A (page 6-7, FIG. 4-6)

  However, in the case of the manufacturing method described in Patent Document 1 described above, the rigidity and torque tend to be lower than when the housing is pre-formed by forging.

  This is because in the case of a cast-molded housing, since the material is difficult to extend, it does not normally undergo caulking deformation, or caulking deformation does not occur within a limited range, so it is difficult to impart elastic strain (preload) due to caulking deformation. In addition, when welding the stud part to the ball part, a welding method with heat generation such as projection welding or friction stir welding is generally used, so that this welding heat is transmitted to the synthetic resin ball sheet. This is considered to be caused by the fact that the ball seat is infinitely deformed (stress relaxation) even though it is small, and the ball seat is in a loose state relative to the ball portion.

  This invention is made | formed in view of such a point, and it aims at providing the manufacturing method of a ball joint which has favorable manufacturability and can obtain appropriate rigidity and torque.

  The method of manufacturing a ball joint according to claim 1, wherein the ball stud having a ball portion, a ball receiving side member having a ball receiving portion, and the ball portion and the ball receiving portion are positioned between the ball portion and the ball receiving portion. A method of manufacturing a ball joint comprising a synthetic resin bearing sheet to be held, wherein a mounting step for obtaining an intermediate body in which the bearing seat is mounted on the outer peripheral side of the spherical body serving as the ball portion; and A molding step of placing in the mold and supplying the molten material into the mold to mold the ball receiving side member; and a compression step of pressing the periphery of the ball receiving side member to impart elastic strain to the bearing seat; Is provided.

  The ball joint manufacturing method according to claim 2 is the ball joint manufacturing method according to claim 1, wherein, in the compression step, an external force is applied in a direction toward the central axis of the ball stud and in a direction along the central axis. The periphery of the ball receiving side member is pressed.

  The ball joint manufacturing method according to claim 3 is the ball joint manufacturing method according to claim 1 or 2, wherein the ball stud has a stud portion protruding from the ball portion, and after the molding step, A welding step of welding the shaft-like body to the spherical body, and the compression step is performed after the welding step.

  The ball joint manufacturing method according to claim 4 is the ball joint manufacturing method according to any one of claims 1 to 3, wherein the ball receiving side member has a plurality of planar pressed parts to the outside at substantially equal intervals. And, in the compression step, elastic deformation is applied to the bearing sheet by pressing each of the pressed parts.

  The ball joint manufacturing method according to claim 5 is the ball joint manufacturing method according to claim 4, wherein the pressed portion is provided at a position including the center of the ball portion in a side view.

  According to the method for manufacturing a ball joint according to claim 1, an intermediate body in which a bearing seat is mounted on the outer peripheral side of a spherical body serving as a ball portion is arranged in a mold, and a molten material is supplied into the mold to receive the ball receiver. By molding the side member, the productivity is improved as compared with the case where the ball receiving side member is separately formed and the intermediate body is assembled, and the bearing seat is elastically strained by pressing around the ball receiving side member. By giving, appropriate rigidity and torque can be obtained.

  According to the ball joint manufacturing method of claim 2, in addition to the effect of the ball joint manufacturing method of claim 1, in the compression step, a direction toward the central axis of the ball stud and a direction along the central axis By pressing the periphery of the ball receiving side member so as to apply an external force to the bearing, it is possible to reliably give an elastic strain to the bearing seat.

  According to the method for manufacturing the ball joint according to claim 3, in addition to the effect of the method for manufacturing the ball joint according to claim 1 or 2, the shaft-shaped body that becomes the stud portion is formed on the spherical body after the molding step. By welding and performing the compression process after the welding, it is possible to prevent the elastic strain applied to the bearing sheet by the compression process from being affected by the welding heat to the spherical body of the shaft-shaped body.

  According to the method for manufacturing a ball joint according to claim 4, in addition to the effect of the method for manufacturing a ball joint according to any one of claims 1 to 3, in the compression step, the ball receiving side member is arranged at substantially equal intervals. By applying an elastic strain to the bearing sheet by pressing each of the provided planar pressed parts, it is possible to apply an external force substantially evenly to the bearing sheet and more reliably apply the elastic strain.

  According to the ball joint manufacturing method of claim 5, in addition to the effect of the ball joint manufacturing method of claim 4, compression is provided by providing the pressed portion at a position including the center of the ball portion in a side view. By pressing the pressed portion in the process, it is possible to reliably apply an external force to the bearing seat in a direction toward the central axis of the ball portion and to apply elastic strain more reliably.

It is a fragmentary sectional view showing the ball joint of one embodiment of the present invention. It is a perspective view which shows a suspension member provided with a ball joint same as the above. It is explanatory drawing which shows the mounting process of the manufacturing method of a ball joint same as the above. It is explanatory drawing which shows the formation process of the manufacturing method of a ball joint same as the above. It is sectional drawing which shows the housing shape | molded by the molding process same as the above. It is a side view which shows the housing shape | molded by the molding process same as the above. It is sectional drawing which shows the welding process and fixing process of a manufacturing method of a ball joint same as the above. It is a top view which shows the compression process of the manufacturing method of a ball joint same as the above. It is sectional drawing which shows the compression process of the manufacturing method of a ball joint same as the above.

  An embodiment of the present invention will be described below with reference to FIGS.

  In FIG. 2, 11 is a stabilizer link that is a suspension member used in a suspension device of a vehicle such as an automobile. The stabilizer link 11 includes ball joints 12 and 12 positioned at both ends, and between these ball joints 12 and 12. And a link portion 13 for connecting these ball joints 12 and 12 to each other. Although the ball joints 12 and 12 located at both ends of the link portion 13 are opposite to each other in the vertical direction, the basic configuration is the same, so only one of the ball joints 12 will be described below. The description of the other ball joint 12 is omitted.

  As shown in FIG. 1, the ball joint 12 includes a ball stud 15 made of metal that is a ball side member, a housing 16 made of metal that is a ball receiving side member, and the housing 16 and the ball stud 15. And a ball seat 17 which is a bearing seat made of a synthetic resin or the like interposed between them.

  The ball stud 15 includes a ball portion 21 that is a substantially spherical head portion, and a round shaft-like stud portion 22 that is protruded from the ball portion 21 and is vertically long, for example, made of metal. A flange portion 23 is formed on the outer peripheral side in the middle in the longitudinal direction of 22 so as to protrude integrally outward. Further, a screw groove (not shown) is formed on the outer peripheral surface on the upper end side of the stud portion 22, and a fixed body (not shown) is fitted to the flange portion 23 by screwing a nut into the screw groove. And fixed between the nut and the nut. The equator X of the ball portion 21 is orthogonal to the axial direction of the ball stud 15 when viewed from the front. Further, the center O of the ball portion 21 is located on the extension of the central axis of the link portion 13.

  The housing 16 is also called a socket, and includes a substantially cylindrical ball receiving portion 26 that holds the ball portion 21 via the ball seat 17, and each ball receiving portion 26 and both longitudinal ends of the link portion 13 in the longitudinal direction. A connecting portion 27 that is a neck portion to be connected, and a clamping seat surface 28 that is a pressed portion that is formed in a plurality of planar shapes around the ball receiving portion 26.

  The ball receiving portion 26 has a first opening 29 at an upper end portion that is one end portion in the axial direction, and a second opening 30 at a lower end portion that is the other end portion in the axial direction. The ball stud 15 is inserted into the first opening 29, and the second opening 30 is closed by a plug 31 which is a substantially disc-shaped lid member.

  The plug 31 has a locking portion 32 at the outer peripheral end, and the locking portion 32 is locked by a caulking portion 33 positioned around the second opening 30, so that the plug 31 is a ball of the housing 16. The second opening 30 is closed by caulking and fixing to the receiving portion 26. A space surrounded by the plug 31, the ball portion 21, and the ball seat 17 is a grease reservoir space 34 that is a lubricant accommodating portion that accommodates grease that is a lubricant (not shown).

  Further, a step portion 35 that is a groove-like cover groove is formed on the outer periphery on the upper end side of the ball receiving portion 26, and between this step portion 35 and the flange portion 23 of the stud portion 22 of the ball stud 15. Is provided with a dust cover 36, which is a substantially cylindrical cover member having an opening on the upper and lower surfaces. The dust cover 36 is also called a dust seal or a boot, and is entirely made of, for example, soft rubber or soft synthetic resin. The upper end portion, which is one axial end portion of the dust cover 36, is fitted on the outer peripheral side of the flange portion 23, and the lower end portion, which is the other axial end portion of the dust cover 36, is placed on the outer peripheral side of the step portion 35 of the ball receiving portion 26. The lower end portion of the dust cover 36 is fixed to the step portion 35 by a clip 38 such as a clip that is a substantially circular annular member. A space surrounded by the dust cover 36, the ball stud 15, the ball receiving portion 26, and the ball seat 17 is a grease reservoir space 39 that is a lubricant accommodating portion that accommodates grease.

  The connecting portion 27 has, for example, a concave substantially concave shape with a cross-sectional shape opened downward, and a hole 41 that is a depression is formed on the lower surface side, and the hole 41 is in the vicinity of the ball receiving portion 26. Is located. Further, the connecting portion 27 is located between the clamping seat surfaces 28 and 28.

  Further, the respective clamping seat surfaces 28 are formed in a planar shape along the vertical direction, and are arranged at substantially equal intervals in the circumferential direction of the ball receiving portion 26. In the present embodiment, for example, three each of the clamping seat surfaces 28 are formed. Each clamping seat surface 28 is formed over a position including the center O of the ball portion 21 in a side view.

  Further, the ball sheet 17 is integrally formed in a substantially cylindrical shape having an opening on the upper and lower surfaces, for example, with a synthetic resin such as polyether ether ketone (PEEK) or fiber reinforced polyimide (PI). That is, the ball sheet 17 has substantially circular end surface openings 44 and 45 at the upper and lower end portions in the axial direction, the opening diameter of which is smaller than the outer diameter of the ball portion 21.

  In addition, a sliding contact surface 46 that is a holding surface communicating with the end surface openings 44 and 45 is formed inside the ball seat 17, and the sliding contact surface 46 rotatably holds the outer peripheral surface of the ball portion 21. doing. Therefore, the ball seat 17 is accommodated in the ball receiving portion 26 of the housing 16 together with the ball portion 21 of the ball stud 15, and the ball portion 21 is disposed on the inner peripheral surface of the ball receiving portion 26 via the ball seat 17. It is held rotatably.

  In addition, the ball seat 17 covers a spherical surface (outer peripheral surface) of about 2/3 including the equator X of the ball portion 21 with a sliding contact surface 46.

  Next, a method for manufacturing the ball joint 12 will be described.

  3 is a spherical body such as a steel ball, and this spherical body 51 becomes the ball portion 21 (FIG. 1) of the ball stud 15. First, the ball sheet 17 which is a resin liner separately molded by injection molding of a synthetic resin in advance is mounted so as to cover the equator X on the outer peripheral side of the spherical body 51 including the equator X. Thus, an intermediate body 52 in which the outer peripheral side of the spherical body 51 is covered with the ball sheet 17 is obtained (mounting process). At this time, for example, the spherical body 51 is inserted into the ball seat 17 from the end surface opening 44 while being inserted into the ball seat 17 while being slightly elastically deformed.

  Next, as shown in FIG. 4, a link-shaped housing 16 that covers the entire outer peripheral surface of the ball seat 17 of the intermediate body 52 and is not in contact with the spherical body 51 by die casting with the intermediate body 52 as a core (FIG. 1). ) (Molding process).

  That is, after the intermediate body 52 is set in a mold 56 having a predetermined shape having a convex portion 55 that forms a shape corresponding to the hole portion 41 of the connecting portion 27, that is, a shape forming the hole portion 41 (FIG. 1), A molten material that is a high-temperature molten metal (for example, a light metal material such as aluminum, or an alloy thereof) is press-fitted and supplied so that a part of the molten material hits the convex portion 55 and then flows into the outer peripheral side of the ball sheet 17 of the intermediate body 52, Thereafter, it is solidified to form the housing 16 (FIG. 1).

  Here, the mold 56 is, for example, an upper and lower divided mold, and includes an upper first mold member 56a and a lower second mold member 56b. In a state where these two mold members 56a and 56b are combined, a ball receiving portion space 57 having a shape corresponding to the ball receiving portion 26 (FIG. 1) and a link having a shape corresponding to the link portion 13 (FIG. 1). A part space 58 and a connecting part space 59 having a shape corresponding to the connecting part 27 (FIG. 1) are formed inside the mold 56. The mold 56 has a gate (not shown) that is a supply port communicating with the link space 58, and the molten material is supplied into the mold 56 from this gate.

  Further, both mold members 56a and 56b have clamping surfaces 61 and 62 for clamping the intermediate body 52 from above and below in a combined state. Further, the lower second mold member 56 b has a convex portion 55 that faces the connecting portion space 59.

  Then, when the intermediate body 52 is inserted into the mold 56 and sandwiched between the both clamping surfaces 61 and 62, when a high-temperature molten material (molten metal) is press-fitted into the mold 56 from the gate, the melt In the mold 56, the material flows from the link portion space 58 through the connecting portion space 59 to the ball receiving portion space 57.

  The melting material is higher than the melting point of the synthetic resin material forming the ball sheet 17, but the ball sheet 17 has a desired heat resistance and is vaporized and consumed to a level where it cannot be used by receiving heat from the melting material. There is no.

  Then, after supplying a predetermined amount of the molten material, the molten material is solidified, and as shown in FIGS. 5 and 6, the ball receiving portion 26, the connecting portion 27 integral with the link portion 13, and each clamping seat A housing 16 having a predetermined shape including the surface 28 is formed. The step portion 35 is formed by cutting the upper outer peripheral side of the ball receiving portion 26 after the housing 16 is taken out from the mold 56.

  Thereafter, as shown in FIG. 7, a ball stud is formed by welding a shaft body 66 made of steel or the like to be the stud portion 22 to the spherical body 51 by using a welding method such as projection welding or friction stir welding. 15 (FIG. 1) is obtained (welding process). Further, the plug 31 is attached to the second opening, and the caulking portion 33 is caulked and deformed to fix the plug 31 to the ball receiving portion 26 (fixing step). The order of these welding steps and fixing steps can be arbitrarily set.

  Then, as shown in FIG. 8, a predetermined external force F1 is applied to each clamping seat surface 28 in a direction orthogonal to the central axis of the ball stud 15 using a jig (not shown) and the like. As shown in FIG. 2, by applying a predetermined external force F2 in the direction along the central axis of the ball stud 15 using the pressing jig 68, the ball portion 21 of the ball stud 15 and the ball receiving portion 26 of the housing 16 are sandwiched. A predetermined elastic strain (preload) is applied to the ball seat 17 by compressing (narrowing) the space where the ball seat 17 is located (the compression step).

  Here, the pressing jig 68 includes, for example, a cylindrical first pressing jig portion 68a that presses the upper outer periphery of the housing 16 and a bottomed cylindrical second portion that presses the vicinity of the caulking portion 33 on the lower side of the housing 16. And a pressing jig portion 68b. Then, the housing 16 is inserted into the first pressing jig portion 68a from the lower side, and the first pressing jig portion 68a is in contact with the outer periphery on the upper side of the housing 16 from the connecting portion 27 to the step portion 35. Then, the upper edge of the second pressing jig portion 68b is pressed from the lower side of the housing 16 to the upper side on the first pressing jig portion 68a side in the vicinity of the caulking portion 33, whereby the ball stud is pressed against the housing 16 A predetermined external force F2 is applied in a direction along the 15 central axis.

  The order in which these predetermined external forces F1 and F2 are applied is arbitrary, and may be, for example, simultaneous.

  Then, as shown in FIG. 1, a dust cover 36 or the like is fixed between the step portion 35 of the ball receiving portion 26 of the housing 16 and the flange portion 23 of the stud portion 22 of the ball stud 15 (fixing step), Get joint 12.

  As described above, according to the above-described embodiment, the intermediate body 52 in which the ball sheet 17 is mounted on the outer peripheral side of the spherical body 51 serving as the ball portion 21 is disposed in the mold 56, and the molten material is contained in the mold 56. By molding the housing 16, the housing 16 and the assembly of the intermediate body 52 can be completed in one step compared to the case where the intermediate body is assembled after the housing is formed by forging, for example. In addition to improving the manufacturability, it is possible to obtain appropriate rigidity and torque by pressing the periphery of the housing 16 and applying an elastic strain (preload) to the ball seat 17.

  That is, when casting the housing 16 using the intermediate body 52 as a core, the material is hard to extend compared to the forged housing, and the caulking deformation is performed only within a limited range, so that elastic strain due to caulking deformation is applied. Since the ball seat 17 is in a loose state with respect to the ball portion 21, the space between the ball portion 21 of the ball stud 15 and the ball receiving portion 26 of the housing 16 is pressed around the housing 16 That is, by compressing (narrowing) a space in which the ball seat 17 is present, a predetermined elastic strain (preload) can be applied to the ball seat 17, and an appropriate rigidity and torque can be obtained by this elastic strain. it can.

  Specifically, in the compression process, by pressing the periphery of the housing 16 so as to apply an external force in a direction toward the central axis of the ball stud 15 and a direction along the central axis, the elastic deformation is surely caused by the ball seat 17. Can be given.

  In addition, after the molding process, a welding process is performed in which the shaft-like body 66 to be the stud part 22 is welded to the spherical body 51 to be the ball part 21, and the compression process is performed after the welding process. Thus, the elastic strain applied to the ball seat 17 can be prevented from being affected by the heat of welding of the shaft-like body 66 to the spherical body 51. That is, this welding heat is transmitted to the sliding contact surface 46 of the ball seat 17 through the spherical body 51 (ball portion 21), and the sliding contact surface 46 of the ball seat 17 is made to be permanently deformed (stress relaxation) even though it is minute. There is. Therefore, by performing the compression process after the welding process in which the rigidity and torque from the manufacturing process are once determined, the ball seat 17 can be more reliably elastically strained and the rigidity and torque can be easily managed. become.

  Further, in the compression process, the ball sheet 17 is elastically strained by pressing the plurality of planar clamping seat surfaces 28 provided at substantially equal intervals on the outside of the housing 16, whereby the ball sheet 17 is By applying an external force substantially evenly, elastic strain can be more reliably applied.

  Then, by providing the clamping seat surface 28 at a position including the center O of the ball portion 21 in a side view, the ball seat 21 is pressed against the ball seat 17 by pressing the clamping seat surface 28 in the compression process. An elastic force can be applied more reliably by applying an external force in the direction toward the central axis of the lens.

  In the above embodiment, the compression process is performed after the welding process. However, the effect of applying elastic strain to the ball sheet 17 can be obtained even if the compression process is performed before the welding process.

  Therefore, for example, when the step portion 35 or the like is cut with respect to the housing 16 after the molding process, the housing 16 is fixed (chucked) by a chuck member (not shown), and the clamping member is used for clamping. A predetermined external force F1 may be applied by pressing the seating surface 28. In this case, a separate process and a dedicated jig are not required, and the productivity can be further improved.

  Further, instead of the configuration in which the predetermined external force F2 is applied using the pressing jig 68, for example, the predetermined external force F2 may be applied by using the caulking deformation of the caulking portion 33 for fixing the plug 31 in the fixing process. . In this case, a separate process and a dedicated pressing jig 68 are not necessary, and the productivity can be further improved.

  Furthermore, although the number of the clamping seat surfaces 28 is three, any number can be set as long as the configuration can apply the predetermined external force F1 substantially equally to the ball receiving portion 26 of the housing 16, such as six.

  And, when applying a predetermined external force F1 in the direction toward the central axis of the ball stud 15, it is not limited to the configuration applied to the clamping seat surface 28, and such a clamping seat surface 28 is formed in the housing 16. Instead, the ball seat 17 may be elastically strained by simply pressing the outer periphery of the ball receiving portion 26 of the housing 16.

  Further, the method of molding the housing 16 by die casting using the intermediate body 52 as a core is not limited, and for example, a method of molding the housing 16 by injection molding of a synthetic resin using the intermediate body 52 as a core may be used.

  Further, the ball seat 17 may have, for example, a divided structure divided into a plurality of parts.

  In addition to the stabilizer link 11, the manufacturing method of the present invention can also be applied to the manufacture of a ball joint having no link, the manufacture of a ball bush (pillow ball) as a ball joint, and the like.

12 Ball joint
15 Ball stud
16 Housing as ball receiving side member
17 Ball seat as bearing seat
21 Ball part
22 Stud section
26 Ball receiver
28 Clamping seat that is the pressed part
51 Spherical
52 Intermediate
Type 56
66 Center of shaft O

Claims (5)

A ball stud having a ball portion;
A ball receiving side member having a ball receiving portion;
A ball joint manufacturing method comprising a synthetic resin bearing seat positioned between the ball portion and the ball receiving portion and holding the ball portion,
A mounting step of obtaining an intermediate body in which the bearing seat is mounted on the outer peripheral side of the spherical body serving as the ball portion;
A molding step in which the intermediate body is disposed in a mold, and a molten material is supplied into the mold to mold the ball receiving side member;
A method of manufacturing a ball joint, comprising: a compression step of pressing the periphery of the ball receiving side member to impart elastic strain to the bearing seat. 2. The ball joint manufacturing method according to claim 1, wherein in the compression step, the periphery of the ball receiving side member is pressed so as to apply an external force in a direction toward the central axis of the ball stud and in a direction along the central axis. . The ball stud has a stud portion protruding from the ball portion,
After the forming step, a welding step of welding the shaft-like body serving as the stud portion to the spherical body,
The method for manufacturing a ball joint according to claim 1, wherein the compression step is performed after the welding step. The ball receiving side member has a plurality of planar pressed parts outside at substantially equal intervals,
The method for manufacturing a ball joint according to any one of claims 1 to 3, wherein in the compression step, an elastic strain is applied to the bearing sheet by pressing each of the pressed parts. The method for manufacturing a ball joint according to claim 4, wherein the pressed part is provided at a position including the center of the ball part in a side view.

Images