1. Technical Field
The present invention relates to an electromagnetic switch. In particular, the present invention relates to an electromagnetic switch provided with a single cylindrical frame and two electromagnets which are accommodated in the frame in parallel with each other in the axial direction of the solenoids.
2. Related Art
One of conventional electromagnetic switches used for a starter of a vehicle is disclosed in Japanese Patent Laid-open Publication No. JP-A-2009-191843.
This electromagnetic switch has a first electromagnet for moving the pinion gear of the starter to a ring gear of an engine, and a second electromagnet for closing and opening a main switch. This switch additionally has a cylindrical frame in which the two electromagnets are set in parallel with each other in the axial direction of the switch, and a plastic cover which covers an open end of the frame and is fixed to the frame.
FIG. 10 shows a schematic view of the electromagnetic switch viewed in the axial direction.
Two terminal bolts 110, 120 connected to a motor circuit are fixed to the plastic cover 100. A first exciting terminal 130 to be connected to a first coil of the first electromagnet is shown at the right side of the two bolts, and a second excitation terminal 140 to be connected to a second coil of the second electromagnet is shown at the left side of the two bolts in FIG. 10.
The first coil of the electromagnetic switch in JP-A-2009-191843 includes an attracting coil and a holding coil. In addition to the first and second excitation terminal 130, 140, the electromagnetic switch has a negative terminal 150 which is connected to a negative end of the attracting coil. The negative terminal 150 is projected from the plastic cover 100 to the axial direction, electrically connected to the terminal bolt 120 of the motor through an attachment clasp.
As shown in FIG. 10, the first and second excitation terminals 130, 140 face each other across the two terminal bolts 110, 120. Therefore it is necessary to wire up one of the excitation terminals 130, 140 before attaching the starter to the engine block. For example, when the engine block and the second excitation terminal 140 are arranged at the left side of the plastic cover 100 in FIG. 10, it is difficult to wire up the second excitation terminal 140 with the starter attached to the engine block. Accordingly, it is required to wire up the second excitation terminal 140 before attaching the starter to the engine block and to wire up the first excitation terminal 130 after attaching the starter to the engine block. This needs twice work of wiring before and after attaching the starter to the engine, and work efficiency is low.
The positional relationship of terminals to be wired up is different according to the engine model. It is necessary to change the position of the first and second excitation terminals 130, 140 according to the difference.
Here a method of change the position of the first and second excitation terminals 130, 140 by rotating about an axis of the frame is discussed.
The terminal which is wired up after attaching the starter to the engine is defined as a basis position terminal (first excitation terminal 130 in the case described above). When the first and second excitation terminal 130, 140 are rotated about the axis with respect to the frame for changing the position of the basis position terminal from lower right to lower left, the positions of the first and second excitation terminal 130, 140 move from the position shown in FIG. 11 to the position shown in FIG. 12 with the positional relationship among the negative terminal, the first and second excitation terminal 130, 140 kept.
In the above described case, the negative terminal 150 is positioned in a contact space. The contact space is the space where a main switch is arranged. The main switch has a pair of fixed contacts which are connected to the two terminal bolts 110, 120, and a movable contact which closes and opens between the pair of fixed contacts. The electromagnetic switch in JP-A-2009-191843 is configured so that the first and second excitation terminals 130, 140 face each other across the contact space. In such an electromagnetic switch, rotating the first and second excitation terminals 130, 140 about the axis cannot change the position of the basis position terminal to the desired position often.
In the case of changing the position of the basis position according to the engine model and the like, for example as shown in FIG. 13 and FIG. 14, it is required to set the appropriate positional relationship between the first and second excitation terminals 130, 140 such that the other terminal wired up in advance (the second excitation terminal in FIG. 12) and the negative terminal 150 don't reach to the contact space. The change needs changing a position defined as a taking position for taking the first coil from a bobbin around which the first coil is wound. Therefore setting a plurality of variations according to different positions of terminals needs a plurality kind of bobbins according to the variations.
This cause the number of the component and the equipment used for setting the terminals in the electromagnetic switches according to a plurality of variations to increase. As a result, the production cost increases.