In a conventional ABS actuator, a fluid passage through which brake fluid flows is formed in a housing, and opened and closed by a solenoid valve. Furthermore, the solenoid valve is retained between the housing and a case (i.e. cover) made of resin. The case is provided with a protruding portion for supporting a coil (hereinafter referred to as coil-supporting protruding portion), which protrudes towards a brim portion of a yoke so as to abut with the brim portion. A coil height, that is, a distance between a contact surface (i.e. datum surface) and an end surface of the yoke on a side of the housing is adjusted to a predetermined value by pressing the coil-supporting protruding portion (for example, as disclosed in Japanese Patent Laid-Open Publication No.2002-243056).
The coil height is adjusted before the solenoid valve is retained between the housing and the case. Specifically, as shown in FIG. 7, a punch 104 of a pressing jig 103 is caused to abut with a yoke 43 in a state where a case 8 is supported by a supporting jig 101. Then, the yoke 43 is pressed toward a side of a coil-supporting protruding portion 81 until the pressing jig 103 abuts with a datum plate 102, whereby the coil-supporting protruding portion 81 is deformed.
However, in the conventional ABS actuator as described above, since the case 8 is a resin mold product, waviness (concave and convex) appears on a contact surface 89 of the case 8 with the supporting jig 101, in other words, accuracy in flatness of the case 8 is not high. Therefore, it is difficult to cause the contact surface 89 of the case 8 and a contact surface of the supporting jig 101 to be in contact with each other before the case 8 is pressed by the pressing jig 103. Accordingly, the case 8 is bent when pressed by the pressing jig 103, and it returns to an original wavy shape when a press load is removed. This bending and restoration of the case 8 causes a wrong coil height.
Meanwhile, in resin molding, it is difficult to adjust a die to be used for molding (hereinafter referred to as molding die) such that accuracy in flatness of an entire wide surface becomes high. Therefore, an attempt is made to reduce bending of the case 8 when it is pressed, by adjusting the supporting jig 101 so as to match the waviness of the case 8, whereby the contact surface of the case 8 and that of the supporting jig 101 are in contact with each other as close as possible. Despite this attempt, it is not easy to adjust the supporting jig 101 over the entire contact surface thereof with the case 8.