JP2003262176A - Starter and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a starter capable of preventing the occurrence of wear between contact points due to chattering. <P>SOLUTION: This starter S provided with a fixed contact point FS, a movable contact point MS for abutting on the fixed contact point, and a magnet switch MgSw having a pull-in coil PC for electromagnetically driving the movable contact point and a holding coil HC is also provided with a switch Sw1 for the pull-in coil for switching the pull-in coil between excitation and extinguishment separately from an abutment of the movable contact point on the fixed contact point. After the movable contact point abuts on the fixed contact point, the movable contact point can be brought in pressure-contact with the fixed contact point by the electromagnetic force of the pull-in coil by controlling the switch for the pull-in coil to excite the pull-in coil. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a starter and a control method thereof.

[0002]

2. Description of the Related Art A starter for starting an engine is required to have a high output (torque), and accordingly, a large current flows through a motor section. Therefore, the interruption of the current is performed by a magnet switch having a fixed contact and a movable contact, like the relay. This magnet switch MgS
A circuit diagram of a conventional starter S composed of w and a motor M is shown in FIG.

When an ignition switch (starting switch) IngSw of an automobile or the like is turned on (START position), the starter relay SR operates in response to the signal.
As a result, first, a current flows from the power source (battery) B to the pull-in coil PC and the holding coil HC arranged in parallel. Then, the excited pull-in coil PC and holding coil HC move the plunger P made of a movable iron core. The movable contact M that moves integrally with the plunger P electrically connects, that is, electrically connects the fixed contact FB on the power source side and the fixed contact FM on the motor side. Thus, the fixed contact FS (FB, F
The electric power is directly supplied from the power source B to the motor M via M) and the movable contact MS.

When the fixed contacts FB and FM are electrically connected, both ends of the pull-in coil PC have substantially the same potential because the resistance between the fixed contact and the movable contact is low, and the pull-in coil PC is almost the same. Although the current does not flow and the demagnetization state occurs, the contact state between the movable contact M and the fixed contact F is maintained by the electromagnetic force of the holding coil HC.

[0005]

However, when the pull-in coil PC and the holding coil HC are excited to bring the movable contact MS into contact with the fixed contact FS, a collision occurs between them. Moreover, at this time, since the pull-in coil PC is demagnetized at the moment when the movable contact MS contacts the fixed contact FS, the pressure contact force of the movable contact MS to the fixed contact FS is weakened. As a result, the movable contact MS easily bounces from the fixed contact FS. And, even within a short time, the movable contact M
When S bounds from the fixed contact FS, chattering occurs between both contacts. When this chattering occurs, sparks are generated and the contact life is shortened.

The present invention has been made in view of the above circumstances, and provides a starter capable of stably abutting a movable contact and a fixed contact to prevent chattering between the contacts, and a control method thereof. The purpose is to

[0007]

Therefore, the present inventor has diligently studied to solve this problem, and as a result of repeated trial and error,
The inventors have come up with the idea of exciting the pull-in coil even after the contact between the movable contact and the fixed contact, and have developed the starter of the present invention. That is, the starter of the present invention is
A fixed contact composed of a power supply side contact connected to a power supply side terminal extending from a power supply and a motor side contact connected to a motor side terminal extending to the motor, and an electrical connection between the power supply side contact and the motor side contact by abutting the fixed contact. A movable contact that electrically connects the power source side contact and the motor side contact by disconnecting the fixed contact from the fixed contact, and a return spring that urges the movable contact in a direction to separate from the fixed contact. A pull-in coil capable of electromagnetically driving a movable iron core movable integrally with the movable contact in a direction in which the movable contact abuts the fixed contact against the biasing force of the return spring; and the fixed contact and the movable contact. In a starter having a magnet switch, which comprises a holding coil capable of electromagnetically driving and holding the movable core in a contact state with the Characterized in that independently of the abutment to the fixed contact of the contact includes a pull-in switch coil that can switch the excitation or demagnetization of the pull-in coil. When the movable contact is brought into contact with the fixed contact, not only the pull-in coil but also the holding coil is usually excited to rapidly electromagnetically drive the movable iron core.

Here, unlike the conventional starter, the starter of the present invention includes a pull-in coil switch. With this pull-in coil switch, the pull-in coil can be demagnetized independently of the contact of the movable contact with the fixed contact. Therefore, for example, as a control method of the starter, by controlling the pull-in coil switch, it is possible to keep the pull-in coil in an excited state for a predetermined time after the movable contact contacts the fixed contact. Thus, the bound of the movable contact, which is likely to occur immediately after the movable contact comes into contact with the fixed contact, can be suppressed by the strong electromagnetic force of the pull-in coil. That is, the bounce is suppressed or prevented. As a result, chattering between the movable contact and the fixed contact is eliminated, and the life of those contacts can be extended.

Next, consider the case where the starter switch such as an ignition switch is returned from ON to OFF. Then, the motor of the starter cannot be stopped immediately, but continues inertial rotation for a certain period of time, during which the motor functions as a generator. And the input terminal of the motor is
It becomes an output terminal (high voltage terminal) for the generated power.
Here, if the pull-in coil is separated from the circuit from the power supply to the motor, and the excitation / demagnetization of the pull-in coil is independent of the contact of the movable contact with the fixed contact, the power generated by the motor is different from the conventional one. No discharge in coil or holding coil. As a result, unless the circuit for discharging is provided separately, the motor continues inertial rotation for a long time and holds the terminals of the motor (terminals on the motor side, contacts on the motor side, etc.) at a high voltage.

When the motor continues to rotate by inertia for a long time, the wear of the bearings of the motor progresses and the life of the starter is shortened. In addition, when the voltage of the motor side terminal or the like is high, it becomes difficult for the current to flow from the power source to the motor when the starter operation is repeatedly performed, which may cause a time lag in starting the starter.
For example, the engine does not start with the first starter operation,
This is the case if the starter is immediately re-operated. Therefore, it is preferable that the starter of the present invention further has a circuit for discharging the power generation of this motor. For example, a discharge switch capable of discharging electric power generated by inertial rotation of the motor may be provided on a circuit from the motor side contact to the motor. The control of the discharge switch may be performed, for example, at least after the starter switch (eg, ignition switch) of the starter is cut off for a predetermined time.

The starter of the present invention is sufficient as long as it has the magnet switch having the above-mentioned configuration, and any other configuration may be used. Therefore, the magnet switch does not necessarily have to be a drive source for pushing the pinion gear of the starter toward the ring gear of the engine. Also,
The starter may be a torque type (non-reduction type) or a high speed type (deceleration type). Further, the speed reducing mechanism may be an external gear reducing type or an internal gear reducing type.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Next, the present invention will be described more specifically with reference to embodiments. FIG. 1 shows a cross-sectional view of a magnet switch MgSw used in a starter S which is an embodiment of the present invention. This magnet switch MgSw is
First, the battery terminal (power supply side terminal) TB connected to the + terminal of the battery B and the motor terminal (motor side terminal) TM connected to the + terminal of the motor M are fixed to the resin case JC. The battery terminal TB has a battery-side contact (power-side contact) FB at its tip and a motor terminal T.
Each of the Ms has a motor-side contact FM at the tip thereof, and each of them is surrounded by a resin case JC.

The battery side contact point FB and the motor side contact point FM face each other in a tapered shape and form a fixed contact point FS. The fixed contact FS is also brought into contact with the tapered movable contact MS to electrically connect the battery side contact FB and the motor side contact FM. Although the contacts are tapered here, they may have a general planar shape.

The movable contact MS is fixed to a plunger P which is a movable iron core. A cylindrical sleeve SL is fitted on the outer peripheral side of the plunger P, and a cylindrical bobbin BN with a collar is fitted on the outer peripheral side of the sleeve SL. Then, in consideration of heat generation, the bobbin BN has a pull-in coil PC and a holding coil HC in order from the inner side (lower layer side).
And are wound. The pull-in coil PC and the holding coil HC are wound in the same direction with the same number of turns. However, in consideration of the attractive force to be exerted, the pull-in coil PC has a larger wire diameter and a smaller resistance value than the holding coil HC.

The outer peripheral side of these is surrounded by a frame F. Further, a ground plate GP to which one end surface of the plunger P is attracted is fixed to the approximate center of the magnet switch MgSw. A magnetic circuit is formed by the iron ground plate GP, the frame F, and the plunger P. And pull-in coil PC
When the holding coil HC is excited, the plunger P is attracted to the ground plate GP. That is, the plunger P is electromagnetically driven in the direction of the arrow in the figure.

The return spring RS biases the plunger P in the direction opposite to the arrow in the figure. Further, the contact spring CS gives an appropriate contact pressure between the movable contact MS and the fixed contact FS when the movable contact MS moves. In addition, drive spring DS
Provides a forward force for engaging a pinion gear (not shown) with a ring gear (not shown) on the engine side from a joint portion J via a lever.

Next, a circuit diagram of the starter S is shown in FIG.
The starter S includes the magnet switch MgSw, the motor M, a pull-in coil switch Sw1 that controls the pull-in coil PC, and a discharge switch Sw2 that switches discharge of electric power generated by the motor M. Then, the battery B, which is a power supply source (power source) to the starter S, the starter relay SR that switches the connection and disconnection of the large current supplied from the battery B, and the electronic control unit ECU that controls the switching of each switch. , Driven and controlled.

Here, the starter relay SR may be integral with the starter S or may be separate from the starter S. Further, as is apparent from FIG. 2, the electronic control unit ECU is configured so that the engine speed N and the ignition switch I
Based on the ON / OFF signal of ngSw, the starter relay SR, the pull-in coil switch Sw1 and the discharge switch Sw2 are appropriately switched and controlled.

By the way, the electric power is supplied from the battery B to the motor M via the magnet switch MgSw. Power is supplied to the pull-in coil PC and the holding coil HC via the starter relay SR. One end of the pull-in coil PC is connected to one end of the pull-in coil switch Sw1 (collector of the transistor Tr1 in the figure). That is, one end of the pull-in coil PC is not connected to the circuit from the battery B to the motor M as in the conventional case. Therefore, the current flowing to the pull-in coil PC is controlled exclusively by the pull-in coil switch Sw1 and is independent of ON / OFF of the magnet switch MgSw.

However, if the wiring of the pull-in coil PC is set as described above, when the motor M is in a power generating state, conventionally, the pull-in coil PC and the holding coil H are formed.
The current flowing through C stops flowing. Therefore, the circuit for discharging the electric power generated by the motor M is a circuit from the discharging switch Sw2 to the ground via the resistor R.

Next, the operation of the starter S, particularly the magnet switch MgSw, will be described with reference to FIGS. 3 and 4. 3 is a control flow performed by the electronic control unit ECU, and FIG. 4 is a time chart at that time. First, the ignition switch IngSw is set to the START position in order to start the engine. Then, the signal is sent to the electronic control unit ECU (step S1). Upon receiving this ON signal, the electronic control unit EC
U simultaneously sends an ON signal to the starter relay SR and the pull-in coil switch Sw1 (step S2). When both the starter relay SR and the pull-in coil switch Sw1 are turned on, a current corresponding to each resistance value flows from the battery B to the pull-in coil PC and the holding coil HC.

By the excitation of the pull-in coil PC and the holding coil HC, the plunger P quickly moves against the return spring RS, and the movable contact MS.
The fixed contacts FS (FB, FM). In the conventional starter S, the pull-in coil PC is substantially demagnetized by the contact between the movable contact MS and the fixed contact FS, and the plunger P is attracted and held by the ground plate GP only by the electromagnetic attraction force generated by the excitation of the holding coil HC. It had been.

However, this may cause the movable contact MS to bounce from the fixed contact FS and cause chattering, as described above. Therefore, in the present embodiment, the above step S2
After the starter relay SR and the pull-in coil switch Sw1 are turned on, the time t ₀ (several to several tens of ms) until the movable contact MS comes into contact with the fixed contact FS, in addition to the pull-in coil switch Sw1. The duration time for turning on is extended by Δt, and t ₁ (= t ₀ as a whole)
+ Δt) (step S3).

As a result, the movable contact MS becomes the fixed contact FS.
Even after the first contact, the resultant force of the attraction forces of the pull-in coil PC and the holding coil HC acts on the plunger P, and the movable contact MS is more strongly pressed against the fixed contact FS. Therefore, even if the movable contact MS abruptly contacts the fixed contact FS, the movable contact MS practically does not bounce, and chattering that causes a problem hardly occurs. In the present embodiment, Δt is set to the same level as t _0, and t ₁ is set to tens to tens of ms. When the movable contact MS settles on the fixed contact FS after this time t ₀ , the electronic control unit ECU turns off the pull-in coil switch Sw1 (step S4).

The magnet switch MgSw is turned on.
After that, the power is supplied from the battery B to the motor M.
Is being supplied, the motor M rotates the engine (not shown)
Number N ₀Is cranking with. And the engine arrives
When it is heated and begins to rotate itself, its speed increases. So
The engine speed N is determined by each engine
Number N₁ The engine will normally stop when the
Stable idling speed N without₂Continue rotation with
I will start to kick. The engine speed N is N₁
If you exceed the limit, cranking by Starter S is no longer possible.
It will be important. Therefore, the electronic control unit ECU
The engine speed N is₁Determine whether or not
(Step S5), the engine speed N is N₁Cross over
And the discharge switch Sw2 is turned on (step
S6). As a result, the electric power from the battery B to the motor M is
Most of the current flows through the discharge switch Sw2 and the resistor R.
Is discharged. As a result, the rotation of the motor M decreases and
You

Next, when the engine is started and the ignition switch IngSw is turned off (returned from the START position), the electronic control unit ECU receives the signal (step S7). Then, the electronic control unit ECU
The starter relay SR is turned off (step S8).
Simultaneously with the turning off of the starter relay SR, the holding coil HC is demagnetized, the plunger P is biased by the return spring RS to be separated from the ground plate GP, and the movable contact MS is separated from the fixed contact FS. Then, the electrical continuity of the fixed contact FS is cut off (that is, the magnet switch MgSw is turned off), and the power supply from the battery B to the motor M is also cut off.

However, even if the magnet switch MgSw is turned off and the power supply from the battery B is cut off, the motor M continues to rotate by inertia. Therefore, in the present embodiment, the ignition switch IngSw is turned off.
After that, the discharge switch Sw2 is kept in the ON state (starter S9). As a result, the electric power generated by the inertial rotation of the motor M is discharged through the discharging switch Sw2 and the resistor R. At this time, a current flows in the motor M in the opposite direction to that in the past, and the rotation of the motor M rapidly decreases due to the electromagnetic brake action. In addition, the electric potential of the motor side contact FM is maintained at substantially zero by this discharge. As a result, even if the engine is restarted by the starter S within a short time after the engine stalls, the starter S operates without a time lag or the like.

As is clear from the circuit diagrams of FIGS. 2 and 5, in the present embodiment, the pull-in coil PC and the holding coil HC do not discharge, but in the conventional case, the pull-in coil is not discharged. The discharge was performed via the PC and the holding coil HC. Therefore, if the same level of discharge as before is performed,
The resistance value of the resistor R shown in FIG. 2 may be set to a combined resistance value (several Ω) of the pull-in coil PC and the holding coil HC. Thus, the ignition switch IngS
elapsed since w OFF for a predetermined time t ₂ is coasting of the motor M at was Osamu', the electronic control unit ECU turns OFF the discharge switch Sw2.

In this way, the starter S of this embodiment is
In addition to performing the same function as a conventional starter, when the magnet switch MgSw is turned on, the movable contact MS is stably pressed against the fixed contact FS, and chattering is effectively prevented. In the above-described embodiment, the power transistors Tr1 and Tr2 are used as the pull-in coil switch Sw1 and the discharge switch Sw2, respectively, but other switching elements may be used as long as they can secure a desired operation time. May be. Moreover, you may combine a relay etc. suitably.

[0030]

According to the present invention, it is possible to prevent wear between contacts due to chattering while maintaining the function of a conventional starter.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram of a starter according to the embodiment.

FIG. 3 is a flowchart showing a control flow of the starter according to the embodiment.

FIG. 4 is a timing chart of each part constituting the starter according to the embodiment.

FIG. 5 is a circuit diagram of a conventional starter.

[Explanation of symbols]

S Starter B battery (power supply) M motor MS movable contact FS fixed contact FB Battery side contact (power supply side contact) FM motor side contact TB battery terminal (power supply side terminal) TM Motor side terminal RS return spring P plunger (movable iron core) PC pull-in coil HC holding coil Sw1 Pull-in coil switch Sw2 discharge switch MgSw magnet switch (starting switch)

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01H 47/32 H01H 47/32 A H02P 1/18 H02P 1/18 3/12 3/12 DF term (reference) 3G084 BA29 CA01 DA19 DA33 FA36 5G057 AA07 BD02 KK16 5H001 AA01 AB11 AC01 5H530 AA12 BB24 CC06 CD02 CE15 CF08 DD13 EE01

Claims (4)

[Claims] 1. A fixed contact composed of a power supply side contact connected to a power supply side terminal extending from a power supply and a motor side contact connected to a motor side terminal extending to a motor, and the power supply side contact and the motor side contacting with the fixed contact. A movable contact for electrically disconnecting the power supply side contact and the motor side contact by electrically connecting the contact and separating from the fixed contact; and a movable contact in a direction for separating the movable contact from the fixed contact. A return spring that urges, a pull-in coil that can electromagnetically drive a movable iron core that moves integrally with the movable contact in a direction in which the movable contact abuts the fixed contact against the biasing force of the return spring, and the fixed A starter having a magnet switch, comprising a holding coil capable of electromagnetically driving and holding the movable iron core in a state where the movable contact is in contact with the contact, Furthermore, the starter is provided with a pull-in coil switch capable of switching excitation or demagnetization of the pull-in coil independently of contact of the movable contact with the fixed contact. 2. The starter according to claim 1, further comprising a discharge switch for discharging electric power generated by inertial rotation of the motor on a circuit from the motor side contact to the motor. 3. A fixed contact composed of a power supply side contact connected to a power supply side terminal extending from a power supply and a motor side contact connected to a motor side terminal extending to a motor, and the power supply side contact and the motor side by abutting the fixed contact. A movable contact for electrically disconnecting the power supply side contact and the motor side contact by electrically connecting the contact and separating from the fixed contact; and a movable contact in a direction for separating the movable contact from the fixed contact. A return spring that urges, a pull-in coil that can electromagnetically drive a movable iron core that moves integrally with the movable contact in a direction in which the movable contact abuts the fixed contact against the biasing force of the return spring, and the fixed A control method for a starter having a magnet switch, comprising a holding coil capable of electromagnetically driving and holding the movable iron core in a state where the movable contact is in contact with the contact. The starter further includes a pull-in coil switch capable of switching excitation or demagnetization of the pull-in coil independently of contact of the movable contact with the fixed contact, and controlling the pull-in coil switch. A control method for a starter, characterized in that the pull-in coil is kept in an excited state for a predetermined time even after the movable contact has come into contact with the fixed contact. 4. The starter further includes a discharge switch on a circuit from the motor side contact to the motor, the discharge switch being capable of discharging electric power generated by inertia rotation of the motor, and controlling the discharge switch. 4. The starter control method according to claim 3, wherein the discharging is performed for a predetermined time after at least the start switch of the starter is cut off.