JPS62150072A - Starter - Google Patents

Abstract

PURPOSE:To make it possible to perform starter actuation securely by forming either a drive spring or a return spring with shape memory alloy to make the spring loads smaller at higher temperatures and greater at lower temperatures. CONSTITUTION:When an exciter coil 8 of a magnet switch 6 is energized, plunger 7 is attracted to the right, a drive lever 4 turns clockwise about a fulcrum 4b due to a set load of a drive spring 5 to make a pinion 3 move to the left along an output shaft 2 and contact a ring gear 12. Here, if the attraction force of the exciter coil 8 is great, the drive spring 5 is made to be deflected to attract the plunger 7 further under a condition where the drive lever 4 is not moving, to close contact points 9 and 10 to drive a motor 1, and to make a pinion 3 engage with a ring gear 12. The resistance of this exciter coil 8 increases at high temperatures to reduce the attraction forces. By forming the drive spring 5 with shape memory alloy to compensate the reduction in the attraction forces, secure actuation of a starter can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a structure for improving the temperature characteristics of operating voltage in a starter.

[Conventional technology]

The conventional one is Nippondenso Co., Ltd. public technical report, reference number 4.
2-081 (issue date: July 15, 1985), by energizing the excitation coil of the magnetic switch, the plunger is attracted and the lever is rotated.
The pinion is moved to the ring gear side of the internal combustion engine.

When the pinion and ring gear come into contact, the drive spring bends, causing the plunger to move, closing the movable contact and fixed contact provided at one end of the plunger, energizing the starter motor, and causing the pinion to move. is being driven.

[Problem that the invention seeks to solve]

However, in the conventional type described above, the resistance of the excitation coil of the magnetic switch changes significantly depending on the ambient temperature, so at high temperatures, the resistance of the excitation coil increases and the attraction force of the plunger decreases. Therefore, it was necessary to increase the size of the excitation coil in order to obtain a predetermined attraction force at high temperatures.

Conversely, at low temperatures, the resistance of the excitation coil decreases and the attraction force of the plunger increases, causing the drive spring to bend quickly, energizing the starter motor, and rotating the pinion. Therefore, the engagement between the binion and the ring gear deteriorates.Therefore, it is necessary to increase the spring load of the drive spring to improve the engagement between the binion and the ring gear.

In other words, it is necessary to increase the size of the excitation coil of the magnetic switch in consideration of high temperature conditions, and as a result, there is a problem in that the engagement between the binion and the ring gear decreases at room temperature. .

In addition, the set load of the drive spring should be increased in consideration of low temperatures.At normal temperatures, the drive spring does not bend and the movable and fixed contacts cannot close, causing the starter motor to rotate. The problem was that it became difficult.

[Means for solving problems]

Therefore, the present invention has the following features: a pinion that meshes with the ring gear of the internal combustion engine and transmits the rotation of the starter motor; a plunger that moves when an excitation coil is energized to move the pinion toward the ring gear; a normally open contact that is energized by movement to energize the starter motor; and a normally open contact that is bent by movement of the plunger when the binion comes into contact with the ring gear;
The drive spring includes a drive spring for closing the normally open contact, and a return spring for returning the moved plunger to its original position, and either the drive spring or the return spring is formed of a shape memory alloy. The starter is characterized in that the spring force is weakened when the temperature is high or the spring force is strengthened when the temperature is low.

[Effect]

At high temperatures, the plunger can deflect the drive spring or return spring by reducing the set load of the drive spring or return spring.

On the other hand, at low temperatures, it is possible to increase the set load of the drive spring or return spring to obtain a predetermined high load even if the plunger's suction force increases, and improve the engagement between the binion and the ring gear. I can do it.

〔Example〕

The present invention will be described below with reference to embodiments shown in the drawings.

In FIG. 1, ▪ is a motor portion of a starter, and a pinion 3 is helically spline connected to an output shaft 2 of the starter motor portion via an overrunning clutch 3a so as to be slidable in the axial direction. A drive lever 4 has a lower end 4a engaged with a recess 3b at the rear end (on the motor 1 side) of the overrunning clutch 3a, and a fulcrum 4b rotatably supported by the housing 20. Also, the coil part 5a of the drive spring 5 is the fulcrum 4b, and the lower end 5b is the fixing hole 4C.
%5C is engaged with and supported by the hook portion 7a of the plunger 7.

6 is a magnetic switch, and a plunger 7 is disposed on the inner peripheral side of the excitation coil 8 so as to be movable in the axial direction. 9 is a movable contact attached to the tip of the plunger 7 via an insulating member; 10 is a pair of fixed contacts that the movable contact 9 comes into contact with; the negative contact is connected to the power supply, and the other contact is connected to the motor section 1 It is connected. A return spring 11 for returning the plunger 7 is installed between the other end of the plunger 7 and the yoke 6a of the magnetic switch 6. 13 is a contact spring provided between the plunger 7 and the movable contact 9; 12 is a ring gear attached to the internal combustion engine, and to which the pinion 3 engages and disengages.

Next, the operation of the above-described configuration will be explained.

When the excitation coil 8 of the magnetic switch 6 is energized, the plunger 7 is attracted to the right (towards the fixed contact 10). Due to the set load of the drive spring 5 engaged with the plunger 7, the drive lever 4 rotates around the fulcrum 4b as the plunger 7 moves in the axial direction without deflecting, causing the pinion 3 to move along the output shaft 2. , slide to the left,
It collides with the ring gear 12. At this time, if the attraction force of the excitation coil 8 of the magnetic switch 6 is greater than the spring load of the drive spring 5, the drive spring 5 is bent and the plunger 7 is attracted further to the right while the drive lever 4 does not move. , the movable contact 9 is the fixed contact 1
Touches 0. Then, from a power source (not shown), motor 1
When the pinion 3 is energized, the pinion 3 rotates and meshes with the ring gear 12, thereby driving the internal combustion engine.

In FIG. 2, the horizontal axis shows the moving distance of the plunger 7, and the vertical axis shows the attraction force of the exciting coil 8 and the drive spring 5,
5 is a characteristic diagram showing the spring load of the return spring 11. FIG. To explain the present invention with reference to FIG. 2, the curve a is normally the attraction force of the excitation coil 8 at room temperature, and the spring load characteristics of the drive spring 5 and return spring 11 with respect to the curve vAa are set as shown in A. ing.

The operating voltage is approximately 6.0 cm, ensuring good meshing performance. However, due to the rise in ambient temperature and starter temperature,
When the temperature of the excitation coil 8 of the magnetic switch 6 becomes high, the attraction force at the same voltage as at room temperature decreases to b due to an increase in the resistance of the excitation coil 8. At this time, if there is no change in the spring characteristics of the drive spring 5 or the return spring 11, the operating voltage of the excitation coil 8 will rise, and the plunger 7 may not be able to operate at the supplyable voltage. By forming the drive spring 5 with a shape memory alloy, the spring characteristics (spring load) of the drive spring 5 are reduced by high-temperature transformation to compensate for this decrease in attraction force, as shown in B in Figure 2. Position it slightly lower. And even at high temperatures,
By bending the drive spring 5 and moving the plunger 7, the starter motor 1 can be energized.

Conversely, when the ambient temperature decreases and the temperature of the excitation coil 8 of the magnet switch 6 decreases with respect to room temperature, the resistance of the excitation coil 8 decreases, and the attraction force at the same voltage as at room temperature will change to the dashed line. The spring load of the drive spring 5 or the return spring 11 increases as shown by the solid line A. pinion 3 because it has become smaller.
The meshing property between the ring gear 12 and the ring gear 12 deteriorates. Therefore, in the present invention, by forming the return spring 11 with a shape memory alloy, the increase in attraction force is compensated for by increasing the spring load of the return spring 11 through low-temperature transformation.
As shown by the dashed line C in FIG. 2, it is possible to further ensure the meshing performance between the pinion 3 and the ring gear 12.

Therefore, as shown by the dotted line in Figure 3, generally 6~
When the operating voltage of 8 [V] is applicable between 0 and 100 degrees, as mentioned above, at high temperatures, the spring load of the drive spring 5 is reduced, and at low temperatures, By setting the spring load of the return spring 11 high and changing the spring characteristics by 10% at high and low temperature limits, the solid line shown in Figure 3 can be obtained, which is about -20 degrees to 140 degrees. The operation of the scooter can be improved by setting the same meshing conditions within the range of .

In the above embodiment, the drive spring is used for the high temperature side and the return spring is used for the low temperature side.
The opposite setting is also possible.

Furthermore, when considering only the high temperature side, the spring load of either the drive spring or the return spring may be reduced at high temperatures.

Furthermore, if only low temperatures are considered, the spring load of either the drive spring or the return spring may be reduced at low temperatures.

In addition, in the above-mentioned embodiment, the lever 2 was used as a starter to push out the pinion, but it can be applied to any type of starter as long as it has a return spring or a drive spring.
Of course.

〔Effect of the invention〕

As described above, in the present invention, by forming the drive spring or the return spring with a shape memory alloy, the spring load can be reduced at high temperatures or increased at low temperatures. Even in this case, there is an excellent effect that the starter can be operated reliably.

[Brief explanation of drawings]

Fig. 1 is a partial cross-sectional front view showing an embodiment of the starter of the present invention, Fig. 2 is a characteristic diagram showing the attraction force and spring load of the switch with respect to the stroke of the plunger in the starter of the invention, and Fig. 3 is a graph showing the change in temperature in the starter. FIG. 3 is a characteristic diagram of operating voltage. 1... Starter motor, 3... Binion, 4...
Lever, 5... Drive spring, 6... Magnetic switch, 7... Plunger, 8... Excitation coil, 9... Movable contact, 10... Fixed contact, 11...
・Return spring, 12...Ring gear.

Claims (1)

[Scope of Claims] A pinion that meshes with a ring gear of an internal combustion engine and transmits the rotation of a starter motor, a plunger that moves when an excitation coil is energized and moves the pinion toward the ring gear, and a plunger that moves the pinion toward the ring gear by moving the plunger. a normally open contact that is energized to energize the starter motor; and a drive spring that is deflected by movement of the plunger when the pinion contacts the ring gear and energizes the normally open contact to close. and a return spring for returning the moved plunger to its original position, and either the drive spring or the return spring is made of a shape memory alloy, and is configured to weaken the spring force at high temperatures or to reduce the spring force at low temperatures. A starter characterized in that the spring force is sometimes strengthened.