JP-2024155332-A5 -

Dates

Publication Date

20260507

Application Date

20230421

Description

To achieve the above objective, the present invention features a ball joint comprising a rod-shaped stud portion having a flange-like receiving portion that protrudes in a flange-like manner between a connecting portion that is connected to an object to be connected and a ball portion that has a spherical surface , and a housing that slidably accommodates the ball portion in the stud portion, wherein a surface hardened layer is formed at the boundary portion between the connecting portion and the flange-like receiving portion. Specifically, the method for manufacturing a ball joint comprises a rod-shaped stud portion having a flange-like receiving portion that protrudes between a connecting portion that is connected to an object to be connected and a ball portion that has a spherical surface, and a housing that slidably accommodates the ball portion in the stud portion, wherein the method for manufacturing a ball joint should include a surface hardening layer forming step in which a surface hardening layer is formed at the boundary between the connecting portion and the flange-like receiving portion. According to this, the method for manufacturing a ball joint can be expected to have the same effects as the ball joint described above. The housing 120 is the part that holds the ball portion 114 and is formed in a substantially cylindrical shape by casting or forging a non-ferrous metal such as steel or aluminum. In this case, the housing 120 is formed at the tip of an arm portion that extends in a rod shape to connect to various components of a steering mechanism or suspension mechanism (not shown). The housing 120 has an opening 121 formed at one end of the cylindrical body (upper end in the figure), which opens upward in the figure, and the other end (lower end in the figure) is closed by a plug 122. The plug 122 is a plate-shaped member that closes the other end of the cylindrical housing 120, and is made of steel formed into a roughly circular disc shape with a recess in the center. A ball seat 123, which serves as a bearing seat, is housed inside the housing 120. Furthermore, the operator connects an arm portion (not shown) extending from the housing 120 to other components of a steering mechanism or suspension mechanism (not shown ). This allows the operator to attach the ball joint 100 to the steering mechanism or suspension mechanism. Therefore, in the surface hardening layer formation process, the surface hardening layers 116 and 118 may be formed on the surface of the entire stud portion 110 by performing shot peening on the entire stud portion 110. In this case, in the surface hardening layer formation process, the surface hardening layers 116 and 118 may be formed only on the surface of the flange-shaped receiving portion 115 by masking the parts other than the flange-shaped receiving portion 115 and performing shot peening. Furthermore, in the surface hardening layer formation process, the outer circumference 115c and boundary portions 117 may be partially shot peened using a nozzle that sprays media. Furthermore, in the above embodiment, the stud portion 110 is constructed by integrally molding the connecting portion 111, the ball portion 114, the flange-shaped receiving portion 115, and the ball support portion 119 from the same material. However, the stud portion 110 can also be constructed by molding the ball portion 114 separately and then joining it to the ball support portion 119 using welding or other methods. Furthermore, in the above embodiment, the surface hardening layer formation step involved forming surface hardened layers 116 and 118 on the outer periphery 115c and boundary portion 117 by shot peening. However, the surface hardening layer formation step only needs to form surface hardened layers 116 and 118 on the outer periphery 115c and boundary portion 117 , and does not necessarily need to employ shot peening. Therefore, the surface hardening layer formation step can also form surface hardened layers 116 and 118 on the outer periphery 115c and boundary portion 117 by other surface hardening treatments (for example, various heat treatments such as high-frequency induction hardening or flame hardening, nitriding, or carburizing) instead of shot peening.