JPH0973850A - Engage switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase degrees of freedom for design, such as the layout of parts around an internal combustion engine, by electrically connecting pull-in and hold windings in parallel with each other, and obtaining an electromagnetic switch to which a large current can be passed without causing melting or welding of contacts. SOLUTION: A pull-in winding (P, pull-in coil) is provided in the current supply line of a starter motor 10, is supplied with a current via a starter key switch 1 to cause an electrode 2 to be attracted to a pair of contacts 3, and is connected to the pair of contacts at both ends. A hold winding (H, hold coil) 5 is supplied with current via the starter key switch 1, and holds the electrode 2 in contact with the contacts 3. Further, the windings 4, 5 are constructed of two windings, which are electrically connected in parallel with each other and formed into separate layers in a direction parallel to their axes. Thus the winding 4 and the other winding are both wound doubly so that the winding width of a conventional winding can be reduced to 1/2 or less. An electromagnetic switch to which a large current can be passed without causing melting or welding of the contacts is thus obtained.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used as a switch for controlling the opening / closing of a current supplied to a starting motor of an internal combustion engine. The present invention relates to a technique for downsizing an engagement switch.

BACKGROUND OF THE INVENTION Engage switches are widely used to supply current to starter motors of internal combustion engines. As shown in Fig. 4, the engagement switch has a suction winding (P
Coil) 14 and holding winding (H coil) 15, and when the starter key switch 1 operated by the driver supplies a current to these two windings, the suction winding 14 and The holding winding 15 is excited together, and the two windings are connected to the pinion gear 11 mounted on the shaft of the starting motor 10 via the lever 19 and the return spring 18.
Driven axially against the ring gear 12 of the internal combustion engine
Intermesh. The electrode 2 short-circuits the pair of contacts 3 with the pinion gear 11 properly meshed. While supplying current to the starting motor 10 through the electrode 2,
Both ends of the suction winding 14 are connected to the pair of contacts 3, and the suction winding 14 is short-circuited to reduce the required current, and the holding winding 15 maintains the position of the pinion gear 11. Has been done. When the start key switch 1 is opened, the current in the holding winding 15 disappears, the return spring returns the pinion gear 11 to its original position, and the contact between the pair of contacts and the electrode is also released.

The internal combustion engine has been miniaturized and its performance has been improved year by year due to advances in materials, introduction of a supercharging system, electronic control, and the like. It can be seen that the internal combustion engine has been remarkably downsized as compared with the internal combustion engine 10 years ago with the same output. On the other hand, there are few elements that can be miniaturized in the starter motor and the engagement switch,
The proportion of the entire internal combustion engine will increase as the internal combustion engine becomes smaller. Since the starter motor will not be downsized, the degree of freedom in design will be restricted by the arrangement of parts around the engine. It has been found that this is particularly due to the large axial length of the engagement switch. On the other hand, the starting characteristics of the internal combustion engine have been improved. That is, the introduction of the electronic control allows the fuel supply control to be finely performed in accordance with changes in temperature and other environmental conditions. Therefore, it has become possible to shorten the time for operating the starting motor at the time of starting. In particular, the continuous operation time of the starting motor at the time of starting the internal combustion engine during cold weather has been significantly shortened. As a result, the time for which the starting electric motor was operated at the maximum rating was substantially shortened. The time during which current is supplied to the engagement switch has also been significantly shortened. In other words, even if the engagement switch is allowed to generate heat, the temperature rise will not increase. The present invention has been made against such a background, and an engagement engine mounted on an internal combustion engine
The purpose is to miniaturize the switch. In particular, the purpose is to shorten the axial length of the engagement switch. Another object of the present invention is to reduce the cost of the engagement switch and reduce the weight of the engagement switch. Although the drawings show two windings arranged side by side in the axial direction, the structure in which the two windings are provided is not limited to this, and various structures can be adopted.

SUMMARY OF THE INVENTION The present invention is an engagement /
The suction winding and the holding winding of the switch are each configured by two windings, and each of them is connected in parallel. That is, the present invention is provided in a current supply passage of a starting motor, and a current is supplied through a starting key switch to attract an electrode to a pair of contacts and both ends thereof are connected to the pair of contacts. P, pull-in
Coil) and a holding winding (H, hold coil) that holds the electrode in contact with the contact even after current is supplied through the start key switch and the electrode contacts the contact. In the engagement switch described above, the suction winding and the holding winding each include two windings, and the two windings are electrically connected in parallel. The two windings are preferably formed in layers in a direction parallel to the axis. As described above, the present invention is characterized by the double winding of the suction winding and the holding winding. Here, the magnitude φ of each magnetic field generated by the suction winding and the holding winding is φ = k × I × T ampere turn (k is a proportional constant), where I is the exciting current and T is the number of turns. Therefore, if the suction winding and the holding winding are double wound with the same wire diameter, two windings with half the number of turns (T / 2) can be formed in the same shape as the conventional device. This half of the number of turns is electrically connected in parallel to create a magnetic field φ equivalent to that of the conventional device.
In order to generate, the following is obtained: φ = k × I × (T / 2) × 2, but in this case, the DC resistance (R) of the winding is 1
Since it is / 2, the DC voltage for supplying the exciting current I may be 1/2. However, since the terminal voltage is the battery voltage (E) and remains unchanged, the diameter (d) of the winding can be reduced to double the DC resistance of the winding.
The DC resistance of the winding doubling may be the cross-sectional area of the windings ([pi] d ^2/4) 1/2, i.e., the diameter of the windings (1 / √2) be able to. That is, since the volume can be halved as a whole, the winding width of the winding can be reduced to about ½. Winding power consumption (P)
Considering the above, there is no change in the current I of one winding between the conventional device and the device of the present invention, there is no change in the terminal voltage (E), and there are two windings, so P = It becomes E × I × 2, and the amount of heat generated is double that of the conventional device. However, this is an acceptable value because the period of continuous operation at the maximum rating has become shorter as described above. This has been confirmed by experiments. Furthermore, since the diameter (d) of the winding can be reduced to about 1 / 1.4, considering the configuration in which the upper and lower windings are exactly in between in the mounting form of the winding, the entire winding is considered. The volume of can be reduced.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a partial sectional view of a starter motor and an engagement switch showing a configuration of an embodiment of the present invention, and FIG. 2 is a diagram showing a circuit configuration of an embodiment of the present invention. The embodiment of the present invention is provided in the current supply passage of the starting electric motor 10, and the current is supplied through the starting key switch 1 to attract the electrode 2 to the pair of contacts 3 and both ends thereof are connected to the pair of contacts 3. A suction winding (P, pull-in coil) 4 and a holding winding that holds the electrode 2 in contact with the contact 3 even after the electrode 2 has contacted the contact 3 by supplying a current through the start key switch 1. Wire (H, hold coil) 5 and, as a feature of the present invention, a suction winding 4 and a holding winding 5
Is composed of two windings as shown by the solid and broken lines in FIG. 2, and the two windings are electrically connected in parallel. The two windings are formed layer by layer in a direction parallel to the axis. In this embodiment, the two windings are arranged side by side in the axial direction, but the arrangement of the two windings can be variously changed, not necessarily this structure. In this way, the suction winding 4 and the holding winding 5 are double-wound, respectively, to reduce the winding width of the conventional winding to 1
/ 2 or less. That is, the magnitude of the magnetic field generated in each of the suction winding 4 and the holding winding 5 is φ,
When the exciting current is I, the number of turns of the attracting winding 4 and the holding winding 5 is T, and the proportional constant is k, the magnitude of the magnetic field in the case of single winding is φ = k × I × T ampere-turn Becomes This is φ = k × I × (T / 2) × 2 = k × I × T ampere-turn even by electrically connecting two windings of ½ the number of turns T in parallel. The same magnetic field magnitude φ can be obtained. However, in the case of this double winding, since the DC resistance (R) of the winding becomes 1/2, the radius should be set so that the cross-sectional area of the winding becomes 1/2 for the same DC resistance. You can make it smaller.
Since the diameter of the winding cross-sectional area is taken as d is [pi] d ^2/4, the diameter of the winding the cross-sectional area becomes 1/2 d
When _1, since it is _{^{πd 2/4 = 2πd 1 2}} /4, can be the same value of direct current resistance by d ₁ = d × 1 / √2, and the diameter d to 1 / √2 . The current I and the terminal voltage E flowing through the suction winding 4 and the holding winding 5 do not change even if the radius is reduced by double winding the winding, so that the power consumption P Is equal to P = E × I × 2, and the amount of heat generated is doubled, but there is no problem in practice because the time for operating the starter motor at the time of start-up is short. Can be halved.
Further, since the upper and lower windings are placed between the adjacent windings, the winding diameter can be reduced by (2-√3) d / 2 (approximately 0.13d). That is, the height of the winding is about 0.
It can be multiplied by 7. The winding width can be made smaller than 1/2 by allocating the reduction in height in the direction of decreasing the winding width. For example, it can be reduced to 1 / 1.5 (wound width ratio shown in FIGS. 3A and 3B: W ₀ / W≈
1.5). The above is the case where the diameter of the winding is 1 / √2, but the diameter of the winding can be set smaller, for example, 1 / 1.5. In this case, the magnetic field generated by the suction winding 4 and the holding winding 5 becomes small, and the maximum rating becomes small, but the amount of heat generation becomes small. Therefore, the design can be performed so that the diameter of the winding is found as 1 / √2 to 1 / √3 as the optimum design value. here,
The operation of the embodiment of the present invention thus configured will be described. When the start key switch 1 is operated, the battery 1
A current is supplied from 6 to the suction winding 4 and the holding winding 5. The supply of this current excites both the two suction windings 4 and the two holding windings 5, attracts the plunger 17 against the return spring 18, and the pinion gear 11 is provided in the internal combustion engine by the lever 19. Engage with the ring gear 12. Pinion gear 11 is a ring
Until the gear 12 is completely engaged with the gear 12 and the pair of contacts 3 is short-circuited, the electric current passing through the two suction windings 4 is supplied to the starting electric motor 10, so that the starting electric motor 10 rotates gently and the pinion. Send out the gear 11. As a result, the ring gear 12 and the pinion gear 11 are smoothly meshed with each other. When the pinion gear 11 legally meshes with the ring gear 12, the electrode 2 short-circuits the pair of contacts 3 and supplies the main electric current to the starting electric motor 10 through the electrode 2. When the electrode 2 and the pair of contacts 3 are short-circuited, the electric current is not supplied to the suction winding 4. Since the current from the battery 16 is continuously supplied to the holding winding 5, the holding winding 5 maintains the meshed state of the pinion gear 11 and the ring gear 12. When the internal combustion engine is activated and the start key switch 1 is opened, the current supplied to the holding winding 4 is extinguished and the return spring 18 biases the pinion gear 11 via the lever 19 to the original position. It is returned to the position, and the contact between the pair of contacts 3 and the electrode 2 is also released.

As described above, according to the present invention, the axial length of the engagement switch of the starter motor equipped in the internal combustion engine can be shortened and downsized, and the cost and weight can be reduced. Can be mitigated. As a result, the ratio of the engagement switch in the entire internal combustion engine can be reduced, and the degree of freedom in designing the arrangement of parts around the internal combustion engine can be increased.

[Brief description of drawings]

FIG. 1 is a partial sectional view of a starter motor and an engagement switch showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a circuit configuration of an embodiment of the present invention.

3A is a sectional view showing an example of a winding structure of a holding winding and a suction winding in the embodiment of the present invention, and FIG. 3B is a winding structure of a holding winding and a suction winding in a conventional example. Sectional drawing to show.

FIG. 4 is a diagram showing a circuit configuration of a conventional example.

[Explanation of symbols]

 1 Starting Key Switch 2 Electrode 3 Contact 4, 14 Suction Winding 5, 15 Holding Winding 10 Starting Motor 11 Pinion Gear 12 Ring Gear 16 Battery 17 Plunger 18 Return Spring 19 Lever

Claims (2)

[Claims] 1. A current supply passage of a starting motor is provided,
A current is supplied through the start key switch to attract the electrodes to the pair of contacts and both ends of the suction winding are connected to the pair of contacts, and a current is supplied through the start key switch and the electrodes are An engagement switch having a holding winding that holds the electrode in contact with the contact even after the contact is made, wherein the suction winding and the holding winding each include two windings. Engage switches characterized in that their two windings are electrically connected in parallel. 2. The engagement switch according to claim 1, wherein the two windings are formed layer by layer in a direction parallel to the axis.