This application is based upon and claims the benefit of priority of the prior Japanese Patent Application 2005-324720 filed on Nov. 9, 2005 so that the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to an electromagnetic switch of a starter which is turned on in response to a magnetic attraction force generated in an electromagnet to start an operation of an engine.
2. Description of Related Art
A technique for automating assembly of an electromagnetic switch used for a starter has been proposed. in Published Japanese Patent First Publication No. 2002-313205.
As shown in
The cover 110 is disposed so as to protect contact members (not shown) of the switch. The terminal 100 has a stiffness larger than that of a terminal of the coil so as to maintain the shape of the terminal 100 on the outside of the cover 110. With this structure, because the terminal 100 having the stiffness is used to electrically connect the coil with the motor terminal 130, it is not required to extend a terminal of the coil to the outside of the cover 110. Therefore, assembly of an electromagnetic switch including the coil and the cover 110 can be automated.
In cases where the contact members of the switch are changed to new ones to perform maintenance of the switch, portions of the terminal 100 and the plate 120 joined together are cut off, and the cover 110 is taken off from the switch to expose the contact members to the outside of the switch. After the contact members are changed to new ones, the cover 110 is again attached to the switch, and it is tried to again join the terminal 100 and the plate 120 together on the outside of the cover 110.
However, because the joined portions of the terminal 100 and the plate 110 have been already removed, it is difficult to join the terminal 100 and the plate 120 together again on the outside of the cover 110. To join the terminal 100 and the plate 120 together in the maintenance of the switch, it is required to change the terminal 100 and the plate 120 to new ones. Therefore, cost required in the maintenance of the switch is heightened. Further, the coil is wound on a bobbin (not shown), and the terminal 100 is forcibly inserted into the bobbin to be fixed to the bobbin. Therefore, it is difficult to separate the terminal 100 from the bobbin, so that it is required to change both the terminal 100 and bobbin to new ones. Further, the number of work steps required to change parts of the switch is increased. Therefore, not only cost of changed parts is heightened, but also cost for the maintenance work is heightened.
An object of the present invention is to provide, with due consideration to the drawbacks of the conventional electromagnetic switch, an electromagnetic switch wherein a conducting member connected with a motor terminal is easily joined to a terminal electrically connected with an electromagnetic coil without changing the terminal and the conducting member to new ones in the maintenance of the switch.
According to a first aspect of this invention, the object is achieved by the provision of an electromagnetic switch comprising a solenoid having an electromagnetic coil, a contact cover fitted to the solenoid, an electric contact section covered with the contact cover, a terminal electrically connected with the electromagnetic coil and placed within the contact cover, and a conducting member electrically connected with an end portion of the terminal protruded from the contact cover. The conducting member has a plurality of connecting portions joinable to the end portion of the terminal, one of the connecting portions of the conducting member is joined to the end portion of the terminal, and at least one of the other connecting portions of the conducting member is disposed to be separated or detachable from the terminal.
When the solenoid receives an electric current, the electromagnetic coil acts as an electromagnet, and the solenoid generates an attraction force. The electric contact section is set to a closed state in response to the attraction force, and electric power is transmit through the electric contact section.
In cases where the electric contact section is changed to a new one in the maintenance of the switch, the connecting portion of the conducting member joined to the end portion of the terminal is removed from the conducting member to detach the conducting member from the terminal, and the contact cover is detached from the solenoid while the terminal is drawn out from the contact cover. After the electric contact section is changed to anew one, the contact cover is again fitted to the solenoid while the terminal is inserted into the contact cover, and one of the other connecting portions of the conducting member is joined to the end portion of the terminal.
Accordingly, the conducting member connected with a motor terminal can be easily joined to the terminal electrically connected with the electromagnetic coil without changing the terminal and the conducting member to new ones in the maintenance of the switch.
According to a second aspect of this invention, the end portion of the terminal has a plurality of connecting portions joinable to the conducting member, the conducting member is joined to one of the connecting portions of the terminal, and the conducting member is disposed to be separated or detachable from at least one of the other connecting portions of the terminal.
In case of the maintenance of the switch, the connecting portion of the terminal joined to the conducting member is removed from the terminal to detach the conducting member from the terminal. When the contact cover is again fitted to the solenoid, one of the other connecting portions of the terminal is joined to the conducting member.
Accordingly, the conducting member connected with a motor terminal can be easily joined to the terminal electrically connected with the electromagnetic coil without changing the terminal and the conducting member to new ones in the maintenance of the switch.
Embodiments of the present invention will now be described with reference to the accompanying drawings. However, these embodiments should not be construed as limiting the present invention to structures of those embodiments, and the structure of this invention may be combined with that based on the prior art.
An electromagnetic switch is arranged in a starter (not shown) used to start an operation of an engine of a vehicle, and a main contacting section of the switch connects or disconnects a lead wire of a starting motor with or from a terminal of an onboard battery. As shown in
The electric contact section has two fixed contacts 6 and a movable contact 7. The contacts 6 are respectively connected with an external terminal 4 and an external terminal 5. The contact 7 connects or disconnects one fixed contact 6 with or from the other fixed contact 6. The terminal 4 is electrically connected with a battery cable of an onboard battery (not shown), and the terminal 5 is electrically connected with a lead wire of a starting motor (not shown) . When the contact 7 comes in contact with the contacts 6, electric power of the battery is supplied to the motor through the terminals 4 and 5 and the contacts 6 and 7, and the motor starts generating a rotational force. When the contact 7 is detached from the contacts 6, the motor stops generating the rotational force. Mail thread portions of the terminals 4 and 5 are screwed into the cover 3 and are respectively connected with the contacts 6, and the contacts 6 are disposed in a contact chamber 22 surrounded by the cover 3.
The solenoid 2 has a switch yoke 8 formed in a cup shape, an electromagnetic coil 10 wound around a bobbin 9 and disposed in an open space of the yoke 8, a fixed core 11 disposed on a front side (i.e., right side in
The coil 10 has an attracting coil 10a and a holding coil 10b wound around the bobbin 9 in two layers. The coil 10 generates a magnetic field in response to an electric current supplied from the battery so as to magnetize the core 11 and the yoke 8. That is, a fixed magnetic circuit is formed around the coil 10. The coil 10a generates a magnetic attraction force to pull the plunger 13 toward the core 11. The coil 10b generates a magnetic force to hold the plunger 13 being in contact with the core 11.
The core 11 has an outer core 11a formed in a cylindrical shape and an inner core 11b disposed in a center open space of the core 11a. The core 11a is disposed on the front side of the yoke 8. The core 11b is formed in a cylindrical shape, and the shaft 14 is inserted into an center open space of the core 11b. The plunger 13 is disposed to face the core 11b. A return spring 18 is disposed between the plunger 13 and the core 11b so as to forcibly push the plunger 13 toward a rear side (i.e., left side in
The plunger 13 has an open space on the rear side, and a lever driving rod 19 and a lever spring 20 are inserted into the space of the plunger 13. An engaging groove 19a is formed on a surface of an end portion of the rod 19 protruded from the space, and an end of a shift lever (not shown) engages with the groove 19a to transmit a rotational force of the motor to an engine through an output shaft (not shown). The spring 20 is disposed between a collar 21 hitched to an end portion of the plunger 13 on the rear side and a cap 19b disposed on the other end of the rod 19 so as to surround the rod 19. The spring 20 forcibly pushes the cap 19b of the rod 19 against a concave bottom surface of the plunger 13.
The shaft 14 has a flange 14a at its end portion, and the flange 14a is fixed to a front end of the plunger 13 so as to move the shaft 14 with the plunger 13. The other end portion of the shaft 14 is inserted into a center open space of the core 11b and reaches the contact chamber 22. In the chamber 22, the movable contact 7 and the fixed contacts 6 are disposed. The contact 7 is attached to the end portion of the shaft 14 through an insulator 23. A contact spring 24 is disposed between the flange 14a of the shaft 14 and the insulator 23 to forcibly push the contact 7 toward the contacts 6 along the axial. A stopper 25 such as a washer is attached to a top end of the shaft 14 to prevent the contact 7 from being taken off from the top end of the shaft 14. Therefore, the position of the contact 7 on the shaft 14 is fixed by the spring 24 and the stopper 25. A gap length between the contact 7 and the set of contacts 6 is set to be smaller than a gap length between the plunger 13 and the core 11b.
An end portion of the contact cover 13 on the rear side is disposed so as to be adjacent to the core 11 through a rubber packing 26, and is fitted to an end portion of the yoke 8 on the front side by caulking so as to form the contact chamber 22 within the cover 13.
The member 17 electrically connected with the coil 10 is fixed on the cover 3 by the terminal 5, so that the member 17 is electrically connected with the motor through the terminal 5.
An operation of the switch 1 is briefly described. When an ignition key (not shown) is entered into a key receiver or a starting button is switch on, an electric current set at a small value is supplied from an onboard battery to the coil 10 and is transmitted to a starting motor (not shown) through the member 17 and the terminal 5. The motor is earthed. Therefore, the coil 10 generates a magnetic field. That is, the coil 10 acts as an electromagnet. The core 11 is magnetized in response to the magnetic field, and a magnetic attraction force is generated between the core 11b and the plunger 13. In response to the attraction force, the plunger 13 is moved toward the core 11 while compressing the return spring 18 so as to accumulate a resilient force in the spring 18. The shaft 14 fixed to the plunger 13 is pushed out toward the front side, and the movable contact 13 supported by the shaft 14 comes in contact with the contacts 6. Thereafter, the plunger 13 is further moved toward the core 11 while compressing the contact spring 24 and collides with an end surface of the core 11b so as to be stopped. Therefore, a resilient force of the compressed spring 24 is given to the contact 7 so as to forcibly push the contact 7 toward the contacts 6, and the electric contact section is set to a connection state (or closed state). In response to this state, an electric current set at a large value is supplied from the battery to the motor through the contacts 6 and 7 and the terminals 4 and 5 of the electric contact section, so that an operation of the motor is started.
After an operation of an engine of a vehicle is started in response to both the movement of the plunger 13 and a rotational force generated in the motor, the electric current supplied to the coil 10 is automatically stopped, and the attraction force disappears. Therefore, the plunger 13 is pushed back toward the rear side in response to a reaction force of the spring 18, the contact 7 is detached from the contacts 6 so as to set the electric contact section at a disconnection state (or opened state), and power supply to the starting motor is stopped.
Next, the electric connection of the coil 10 with an exciting circuit of the motor is described in detail.
As shown in
As shown in
The washer 17b has a circular opening 17a in its center, and a male thread of the terminal 5 is inserted into the opening 17a. The terminal 5 is screwed into the cover 3 while fastening the washer 17b between the cover 3 and a nut 27 of the terminal 5. Therefore, the washer 17b is fixed to the terminal 5 on the surface of the cover 3.
The portion 17c placed between the washer 17b and the arm 17d is formed in an L shape in section such that a body of the arm 17d is held on the surface of the cover 3 when the washer 17b is fixed to the terminal 5. The portion 17c determines a positional relation between the terminal 16 and the arm 17d.
The arm 17d is formed in an almost V shape in section before being joined to the terminal 16. The arm 17d has a proximal portion 17h adjacent to the portion 17c, a distal portion 17i, and two connecting portions 17f and 17g disposed between the portions 17h and 17i. The portions 17f and 17g face each other through a long and narrow opening 17e along a third direction perpendicular to the first and second directions. The arm 17d is formed by bending a rectangular plate piece extending from the portion 17c at 90 degrees such that the plate piece stands on a plane of the portion 17c, and again bending the plate piece at its middle portion in the second direction such that the plate piece is formed in an almost V shape when being seen along the third direction. Therefore, the portions 17f and 17g are bent in the almost V shape.
As shown in
After the switch 1 is operated for a predetermined period of time, it is required to change the contacts 6 and 7 to new ones in the normal maintenance of the switch 1. In this case, as shown in
Therefore, when the contacts 6 and 7 are changed to new ones, it is not required to change the terminal 16 or the member 17. Accordingly, cost required in the maintenance can be reduced.
Further, because it is not required to change the terminal 16 forcibly inserted into the bobbin 9, it is not required to change the bobbin 9. Therefore, the number of work steps required in maintenance can be reduced. Accordingly, not only cost of changed parts can be reduced, but the maintenance of the switch 1 can be easily performed.
As shown in
When it is intended to change the contacts 6 and 7 to new ones in the normal maintenance of the switch 1, the top portion 16b and the connecting portion 17f are cut off along a cutting line CL. After the contacts 6 and 7 are changed to new ones, the cover 3 is attached to the switch 1, the member 17 is fixed by the terminal 5 on the cover 3, and the connecting portion 17g is turned back so as to surround the root portion 16a. Thereafter, the connecting portion 17g and the root portion 16a are joined or bonded together with solder.
Accordingly, in the same manner as in the first embodiment, cost required in the maintenance can be reduced, and the maintenance of the switch 1 can be easily performed.
In the first and second embodiments, the member 17 has two connecting portions. However, the member 17 may have three connecting portions or more. Because one connecting portion is removed from the member 17 every maintenance of the switch 1, the maintenance requiring the detachment and attachment of the cover 3 from and to the switch 1 can be performed many times.
Further, the connecting portion 17g of the member 17 not joined to the terminal 16 is in contact with the terminal 16. However, the connecting portion 17g may be disposed to be away from the terminal 16 while the connecting portion 17f is joined to the terminal 16.
Moreover, the connecting portion 17f joined to the terminal 16 is turned back so as to surround the terminal 16. However, the connecting portion 17f joined to the terminal 16 may be straightly extended not to surround the terminal 16.
Furthermore, the connecting portions 17f and 17g are disposed so as to be separated from each other through the opening 17e. However, the member 17 may have a single connecting portion not having an opening but have a wide width along an extending direction of the terminal 16. In this case, only a part of the connecting portion nearest to the top of the terminal is joined to the terminal 6 with solder. When the maintenance of the switch 1 is performed, the part of the connecting portion is cut off, and the other part of the connecting portion is joined to the terminal.
As shown in
In the normal maintenance of the switch 1, the divided portion 16c of the terminal 16 and the portion of the arm 17j joined together are cut off along a cutting line CL and is removed from the switch 1. After the maintenance, the joinable area E of the arm 17j and the divided portion 16d are joined together with solder or the like.
Accordingly, in the same manner as in the first embodiment, cost required in the maintenance of the switch 1 can be reduced, and the maintenance can be easily performed.
In this embodiment, the conducting member 17 may have the arm 17d with the portions 17f and 17g. In this case, there are four joinable areas.
Number | Date | Country | Kind |
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2005-324720 | Nov 2005 | JP | national |