JP2646893B2 - Magnet switch device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnet switch device constituting, for example, a starter of an automobile engine.

[0002]

2. Description of the Related Art For example, a magnet switch used for a starter or the like for starting an automobile engine includes an excitation coil wound around a resin bobbin.
An iron plunger core is inserted into the inner periphery of the hollow portion of the bobbin, and the plunger core is configured to be reciprocable.

In this case, a thin hollow metal tube called a sleeve is set in the hollow portion of the bobbin on the inner peripheral surface of the bobbin to protect the bobbin from sliding friction with the plunger core.

For the lubrication between the sleeve and the plunger core, grease is used or a solid lubricant is applied as shown in Japanese Utility Model Laid-Open No. 61-169935, for example. Alternatively, as disclosed in Japanese Utility Model Laid-Open No. 57-66510, a sheet-like lubricant has been proposed.
However, all of these methods have problems in cost and durability.

When the magnet switch is submerged in water, the electrode potential difference between the material such as brass or stainless steel forming the sleeve and the mild steel forming the plunger core is large. Corrosion is likely to proceed, which may hinder switch operation.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and particularly aims at effectively improving the sliding durability of a movable core portion provided with a plunger function. Therefore, even if the movable core is inundated, corrosion of the movable core and the sleeve can be prevented, so that the cost is satisfied and the reliability is improved. It is an object of the present invention to provide a magnet switch device as described above.

[0007]

According to the present invention, there is provided a magnet switch device in which a movable core is movably set inside a sleeve coaxially provided so as to surround a fixed core. A metal film made of a material softer than the material forming the sleeve is formed on the outer circumferential surface that comes into contact with the inner circumferential surface of the sleeve.

[0008]

In the magnet switch device constructed as described above, a metal film softer than the sleeve which guides the movable core is formed on the outer peripheral surface of the movable core controlled to move in the axial direction. Therefore, the metal film acts as a lubricating layer, and the sliding durability of the movable iron core is sufficiently ensured. Further, by selecting the material of the metal film, the potential difference at the contact surface between the sleeve and the outer peripheral portion of the movable iron core can be set to be small. For example, in the case where moisture has entered, corrosion can easily occur. It can be suppressed and has a great effect on improving reliability.

[0009]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a sectional structure of a magnet switch 10, in which a shaft 11 of a clutch mechanism (not shown) is set corresponding to a center axis. This shaft 11 is a rod
The shaft 11 is coupled to a movable core (plunger) 13 which is set in a coaxial state via a shaft 12, and the shaft 11 is linearly driven with the axial movement of the movable core 13, and the starter motor and the engine crankshaft ( (Both not shown) are driven.

A fixed iron core 14 is provided coaxially with the movable iron core 13. A sleeve 15 made of a hollow tube made of, for example, brass or stainless steel is provided so as to be fitted around the fixed iron core 14. And the movable iron core
13 allows the inside of the hollow portion of the sleeve 15 to be moved in the axial direction.

A resin bobbin is provided on the outer periphery of the sleeve 15.
An excitation coil 17 is wound around the bobbin 16. Then, when an exciting current is applied to the exciting coil 17, a magnetic force for attracting and moving the movable iron core 13 toward the fixed iron core 14 is generated.

The movable iron core 13 is provided with a spring 18 whose biasing force is set in a direction away from the fixed iron core 14. When an exciting current is applied to the exciting coil 17, the spring 18 opposes the spring 18. The movable iron core 13 is driven in the direction of the fixed iron core 14. Spring 19 has this movable iron core
A biasing force has been set to help the operation of 13.

The movable core 13 is provided with a movable contact 20 held by an insulator, and fixed contacts 211 and 212 are provided at positions where the movable contact 20 moved together with the movable core 13 comes into contact. The movable contact 20 when 13 is driven
Short circuit the fixed contacts 211 and 212 to form an electrical circuit, for example, to control the drive current supplied to the starter motor.

A cylindrical case 22 is provided on the outer periphery of the magnet switch mechanism configured as described above.
A cover 24 is fastened and fixed to 22 by a bolt 25 via a packing 23 so that the inside is watertight.

FIG. 2 shows the movable core 13 taken out. A metal film 26 is formed on the outer peripheral surface of the movable core 13. The metal film 26 is made of a metal softer than brass or stainless steel forming the sleeve 15, and is made of, for example, tin or an alloy thereof, and has a hardness of about Hv30. In this case, the metal film
26 has a thickness of 4 to 30 μm, and may be formed by electroplating, sputtering or the like.

In the magnet switch device configured as described above, the movable core 13 is set to be separated from the fixed core 14 as shown in the figure, with no current supplied to the exciting coil 17.

When an exciting current is supplied to the exciting coil 17 in this state, the movable core 13 is attracted in the direction of the fixed core 14, and the rod 12 advances together with the movable core 13 to push out the shaft 11. Then, a pinion (not shown) attached to the tip of the shaft 11 meshes with a ring gear of an engine (not shown).

On the other hand, as the movable iron core 13 moves, the movable contact 20
Short-circuits the fixed contacts 211 and 212, and the starter motor is rotationally driven. Therefore, the pinion is driven by this motor, and the operation of starting the engine is performed.

When the exciting current to the exciting coil 17 is cut off, the movable iron core 13 is moved by the force of the spring 18 to the fixed iron core 14.
The movable contact 20 moves away from the fixed contacts 211 and 212, and the starter motor is stopped. At the same time, since the rod 12 retreats, the meshing state between the pinion and the ring gear is released, and the starter motor and the engine are separated.

In response to such an operation, the outer peripheral surface of the movable iron core 13 is in sliding contact with the inner peripheral surface of the sleeve 15, but the metal film 26 made of a material softer than the material of the sleeve 15 is lubricated. Acting as an agent, the durability of the outer peripheral surface of the movable iron core 13 is improved.

The metal film 26 also has a function of protecting the outer peripheral surface of the movable iron core 13 from rust. In particular, the sleeve
Whereas brass or stainless steel is used as the material of 15, when the metal film 26 is formed of tin, for example, even if moisture exists between the inner peripheral surface of the sleeve 15 and the outer peripheral surface of the movable core 13, The electrode potential difference between the two is small, and the occurrence of corrosion can be reliably suppressed.

In the above embodiment, the metal film 26 such as tin was formed directly on the surface of the movable iron core 13, but as shown in FIG.
Another metal film 27 of, for example, copper, nickel or the like may be formed on the base of 26. By forming such an underlayer, the occurrence of corrosion can be more effectively suppressed.

[0023]

As described above, according to the magnet switch device of the present invention, a metal film softer than the sleeve is formed on the outer periphery of the movable iron core that is repeatedly slid on the sleeve. The lubricity between the movable iron core and the sleeve is improved, and the reliability is improved. Further, since the metal film can be formed of a material different from that of the movable core, it is easy to set the electrode potential difference between the metal film and the sleeve to be small, and the occurrence of corrosion due to the invasion of moisture is reduced. It can be suppressed effectively.

[Brief description of the drawings]

FIG. 1 is a view showing a cross-sectional structure of a magnet switch device according to one embodiment of the present invention.

FIG. 2 is a diagram showing a movable core portion of the embodiment taken out.

FIG. 3 is a view showing another embodiment of a movable core portion.

[Explanation of symbols]

10… magnet switch, 11… shaft, 12… rod,
13: movable core, 14: fixed core, 15: sleeve, 16: bobbin, 17: excitation coil, 10: movable contact , 211, 212: fixed contact, 26: metal film, 27: metal film (base).

Claims (2)

(57) [Claims] 1. A fixed iron core, a metal sleeve provided coaxially with the fixed iron core so as to surround the outer periphery thereof, held on an inner peripheral portion of the sleeve, and movable in the axial direction thereof. A movable core set movably in a direction approaching the fixed core and in a direction opposite to the fixed core; and an electromagnetic coil set on an outer periphery of the sleeve and selectively driving the movable core in the direction of the fixed core by an excitation current. The outer peripheral surface that comes into contact with the inner peripheral surface of the sleeve of the movable iron core is different from the material forming the sleeve ,
A magnet switch device, wherein a metal film made of a material softer than this material is formed. 2. The method according to claim 1 , wherein the metal film and the three
The potential difference between the armature and the sleeve from the potential difference between the armature and the sleeve.
Claims made of material that is also reduced
Item 2. The magnet switch device according to Item 1.