JP2006348804A - Engine starting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably start an engine by providing a torque limiter limiting start torque at a predetermined value or less. <P>SOLUTION: An engine start device 1 is provided with a starter motor 7 supplying start torque to a crank shaft 5a of an engine 5, and a transmitting mechanism 3 transmitting start torque provided by the starter motor 7 to the crank shaft 5a of the engine 5. Also, the transmitting mechanism 3 is provided with the torque limiter 11 limiting start torque transmitted to the crank shaft 5a of the engine 5 at the predetermined value or less. The torque limiter 11 is preferably installed between a drive shaft of the starter motor 7 and a starter pulley 3a, or between the crank shaft 5a of the engine 5 and a crank pulley 3b. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine starter for a vehicle.

2. Description of the Related Art Conventionally, an engine start system is known that starts an engine by switching from a belt type starter to a gear type starter when any abnormality is detected in engine start (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 2004-3434

  The conventional engine starting system has a characteristic that the torque of the DC starter (DC motor) increases rapidly at the time of starting. Due to this excessive torque, the positional relationship between the crankshaft, the crank pulley, and the sprocket that are connected to each other may shift. Due to this deviation, the camshaft connected to the sprocket and the crankshaft are out of synchronization, which may cause an abnormal operation of the engine.

  On the other hand, by setting the starting torque of the DC starter low in advance, the above-described problem can be solved. However, it is possible that the engine cannot be started due to a decrease in the starting torque due to aged deterioration of the DC starter. Further, this problem can be solved by applying a motor generator (M / G) instead of the DC starter, but an inverter or the like is required, which may lead to an increase in cost.

  The present invention has been made to solve such problems, and its main object is to start the engine stably.

  In order to achieve the above object, one aspect of the present invention is a starter motor that supplies a starting torque to a crankshaft of an engine, and a transmission mechanism that transmits the starting torque supplied by the starter motor to the crankshaft of the engine. An engine starting device comprising: a torque limiter for limiting the starting torque transmitted to the crankshaft of the engine to a predetermined value or less; Device.

  In this embodiment, the starter motor refers to, for example, a DC motor. Further, as a characteristic of the DC motor, the torque at the start tends to increase rapidly.

  According to this aspect, the torque limiter limits the starting torque transmitted to the crankshaft of the engine to a predetermined value or less. Thus, for example, even when the starter torque supplied by the starter motor at the time of start is excessive, the starter torque transmitted to the crankshaft of the engine is limited to a predetermined value or less and maintained at an optimum value. Therefore, the engine can be started stably.

  Further, in this aspect, the transmission mechanism includes, for example, a crank pulley connected to a crankshaft of the engine, a starter pulley connected to a drive shaft of the starter motor, and the crank pulley and the starter pulley via a belt. May be connected.

  Further, in this aspect, the torque limiter is interposed between the drive shaft of the starter motor and the starter pulley, or between the crankshaft of the engine and the crank pulley. Thus, the torque limiter can limit the starting torque transmitted to the crankshaft of the engine to a predetermined value or less.

  According to the present invention, the engine can be started stably.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. The basic concept of the engine starting device, the main hardware configuration, the operating principle, the basic control method, and the like are known to those skilled in the art, and thus detailed description thereof is omitted.

  FIG. 1 is a schematic view showing an engine starter according to an embodiment of the present invention. The engine starter 1 according to this embodiment includes a brushed or brushless DC starter motor (DC motor) 7 that supplies a starting torque at the time of starting the engine to the crankshaft 5a of the engine 5 via the transmission mechanism 3. Yes.

  A starter pulley 3a having a built-in one-way clutch that restricts the rotation of the drive shaft in one direction is connected to a drive shaft of the DC starter motor 7 via a torque limiter 11 described later.

  A sprocket 5b and a crank pulley 3b are connected to the crankshaft 5a of the engine 5 by pulley bolts 3c (FIG. 2). The sprocket 5b of the crankshaft 5a and the camshaft are connected by a metal chain or the like. Thereby, the rotation of the crankshaft 5a and the rotation of the camshaft are synchronized. A cam that opens and closes the intake and exhaust valves of the engine 5 is connected to the camshaft. Therefore, the positional relationship between the crankshaft 5a and the camshaft is set in advance via the sprocket 5b and the chain so that the intake and exhaust of the engine 5 is optimally performed.

  In the transmission mechanism 3, the starter pulley 3 a of the drive shaft of the DC starter motor 7, the crank pulley 3 b of the crankshaft 5 a of the engine 5, and the auxiliary shaft of the auxiliary machine (alternator, compressor for air conditioner, water pump, etc.) 9 The pulley 9a is connected and interlocked via the belt 3d. Thereby, the starting torque of the DC starter motor 7 is transmitted to the crankshaft 5a of the engine 5 via the transmission mechanism 3, and the engine 5 is started.

  Between the drive shaft of the DC starter motor 7 and the starter pulley 3a, a torque limiter 11 for limiting the starting torque supplied from the DC starter motor 7 to the crankshaft 5a of the engine 5 is interposed.

  FIG. 3A is a sectional view showing an example of the torque limiter 11, and FIG. 3B is a partially enlarged view of a pair of face cams of the torque limiter 11.

  As shown in FIG. 3A, the torque limiter 11 has a coupling structure in which a pair of face cams 11a and 11b are fitted to each other by a spring member 11c. The drive shaft of the DC starter motor 7 is connected to the end of one face cam 11b, and the starter pulley 3a is connected to the end of the other face cam 11a.

  As shown in FIG. 3B, a cross-shaped concave portion 11d is formed on the cam surface of the face cam 11a on the starter pulley 3a side, and on the cam surface of the face cam 11b on the drive shaft side of the DC starter motor 7. Is formed with a cross-shaped convex portion 11e. That is, the torque limiter 11 has a coupling structure in which the cross-shaped concave portion 11d and the convex portion 11e are fitted to each other by the spring member 11c.

  Normally, the pair of face cams 11a and 11b are firmly pressed and connected by the spring member 11c in a state where the cross-shaped convex portion 11e is fitted in the cross-shaped concave portion 11d. In this case, the starting torque supplied by the drive shaft of the DC starter motor 7 is transmitted to the crankshaft 5a without limitation through the pair of face cams 11a and 11b, the starter pulley 3a, the belt 3d, and the crank pulley 3b. Is done.

  For example, when the starting torque supplied by the drive shaft of the DC starter motor 7 at the time of starting becomes excessive and exceeds a predetermined value, the cross-shaped convex portion 11e comes out of the cross-shaped concave portion 11d and the DC starter motor 7 is driven. The shaft rotates relative to the starter pulley 3a. Thereby, the starting torque supplied by the drive shaft of the DC starter motor 7 is limited.

  In addition, when the starting torque supplied from the drive shaft of the DC starter motor 7 decreases from the above state and becomes smaller than a predetermined value, the pair of face cams 11a and 11b are fitted again and rotate together. In this case, the starting torque supplied by the drive shaft of the DC starter motor 7 is transmitted to the crankshaft 5a without limitation through the pair of face cams 11a and 11b, the starter pulley 3a, the belt 3d, and the crank pulley 3b. Is done.

  The predetermined value of the starting torque is set by adjusting the shape of the cross-shaped convex portion 11e and the concave portion 11d or the spring force of the spring member 11c. For example, the predetermined value of the starting torque is set so that the crankshaft 5a, the sprocket 5b, and the crank pulley 3b connected by the pulley bolt 3c do not slip each other when the starting torque reaches the maximum value. Thereby, the synchronization of the rotation of the rank shaft 5a and the rotation of the cam shaft can be maintained in an optimum state.

  The DC starter motor 7 is connected to the engine ECU, and starts or stops driving based on a control signal from the engine ECU. The DC starter motor 7 is connected to a battery such as a lead battery that supplies power to the DC starter motor 7.

  By the way, due to the characteristics of the DC starter motor 7, when the motor 7 is started, the starting torque rapidly increases, and thereafter, the starting torque decreases as the rotational speed of the drive shaft increases (FIG. 4).

  Further, the starting torque generated by the DC starter motor 7 increases substantially in proportion to the amount of charge of the battery (FIG. 5A). That is, when the charge amount of the battery is small, the starting torque tends to be low, while when the charge amount of the battery is large, the starting torque tends to be high. Further, as shown in (2) of FIG. 5 (a), the contact resistance of the earth, relay, etc. increases due to the increase in internal resistance of the battery and deterioration over time, and the starting torque generated by the DC starter motor 7 tends to decrease. There is. Therefore, at the time of manufacture, as shown in (1) of FIG. 5 (a), even when the engine 5 is configured to be always and stably started by the DC starter motor 7, it is always and stably at the time of deterioration over time. Will not start. The starting torque supplied by the DC starter motor 7 is initially set by adjusting, for example, the internal reduction ratio of the DC starter motor 7 and the ratio (pulley ratio) between the starter pulley 3a and the crank pulley 3b.

  On the other hand, if the initial setting of the starting torque is performed as shown in (3) of FIG. 5B in consideration of aging deterioration, the starting torque tends to increase when the amount of charge of the battery is large and may become excessive. is there. In this case, in the conventional engine starter, the pulley bolt 3c, the sprocket 5b, the crank pulley 3b, and the crankshaft 5a are caused by an excessive start torque transmitted from the DC starter motor 7 to the crank pulley 3b via the belt 3d. Slip occurs between the two (FIG. 2). As a result, the above-described rotation of the crankshaft 5a and the rotation of the camshaft may be out of synchronization.

  On the other hand, in the present invention, when an excessive starting torque is generated by interposing the torque limiter 11 between the drive shaft of the DC starter motor 7 and the starter pulley 3a, (4) in FIG. ), The torque limiter 11 limits the excessive starting torque to a predetermined value or less. As a result, the starting torque transmitted from the DC starter motor 7 to the crankshaft 5a of the engine 5 can always be in an optimum state. Therefore, it is possible to prevent the crankshaft 5a and the camshaft from being out of synchronization and to suppress the abnormal operation of the engine 5. That is, the engine 5 can be started stably.

  Further, in order to suppress the occurrence of the excessive starting torque described above, it is not necessary to set the starting torque of the DC starter motor 7 low in advance. Thereby, even when aged deterioration or the like occurs, the DC starter motor 7 stably generates a starting torque and can start the engine 5 stably as shown in FIG. 5B (5). .

  Furthermore, compared to the case of the engine starter 1 to which the motor generator is applied, since an inverter or the like is not required, the engine starter 1 can be manufactured easily and at low cost. That is, the engine can be stably started while reducing the cost of the engine starting device 1.

  The engine starter 1 according to the present invention can be mounted on any vehicle including a hybrid vehicle that travels using both a motor and an engine, and an idling stop vehicle that automatically stops idling based on a predetermined stop condition. is there. The effect of the present invention becomes more prominent particularly when the vehicle is mounted on a hybrid vehicle or an idling stop vehicle in which the engine is frequently stopped and started.

  As mentioned above, although the best mode for carrying out the present invention has been described using one embodiment, the present invention is not limited to such one embodiment, and within the scope not departing from the gist of the present invention, Various modifications and substitutions can be made to the above-described embodiment.

  In the above embodiment, the torque limiter 11 in which the cross-shaped concave portion 11d and the convex portion 11e are fitted to each other by the spring member 11c is applied, but any torque limiter structure can be applied.

  For example, as shown in FIG. 6, the torque limiter 21 may have a configuration in which a pair of clutch plates 21a are pressed by a compression spring 21c via a friction member 21b. In this case, one clutch plate 21a is connected to the DC starter motor 7, and the other clutch plate 21a is connected to the starter pulley 3a. When the starting torque supplied by the drive shaft of the DC starter motor 7 becomes excessive and exceeds a predetermined value, the pair of clutch plates 21a slide with respect to the friction member 21b, and the drive shaft of the DC starter motor 7 moves with respect to the starter pulley 3a. , Relative rotation. Thereby, the starting torque supplied by the drive shaft of the DC starter motor 7 is limited.

  Further, as shown in FIG. 7, the torque limiter 31 may adopt a viscous coupling structure using the viscosity of silicon oil. Further, as shown in FIG. 8, the torque limiter 41 may employ a magnetic coupling structure that uses an attractive force between a pair of cylindrical permanent magnets 41a and 41b arranged coaxially.

  In the above embodiment, the torque limiter 11 is interposed between the drive shaft of the DC starter motor 7 and the starter pulley 3a, but is interposed between the crankshaft 5a of the engine 5 and the crank pulley 3b. May be.

  In the above embodiment, the torque limiter 11 is connected as a separate unit to the DC starter motor 7. However, the torque limiter 11 is built in the DC starter motor 7, and the DC starter motor 7 and the torque limiter 11 are integrally configured. It may be.

  The present invention can be used for an engine starter for a vehicle. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited.

It is the schematic which shows the engine starting apparatus which concerns on one Example of this invention. It is sectional drawing which shows the state by which the sprocket and the crank pulley were connected with the crankshaft by the pulley bolt. (A) It is a fragmentary sectional view which shows an example of a torque limiter. (B) It is the elements on larger scale of a pair of face cam of a torque limiter. It is a figure which shows the relationship between the rotation speed of the drive shaft of a DC starter motor, and starting torque. (A) It is a figure which shows the comparison with the state of initial setting, and the state deteriorated over time, and is a figure which shows the relationship between the charge amount of a battery, and starting torque. (B) It is a figure which shows the comparison with the case where a torque limiter is interposed, and the case where a torque limiter is not interposed, and is a figure which shows the relationship between the charge amount of a battery, and a starting torque. It is a figure which shows the torque limiter using a clutch board. It is a figure which shows the torque limiter using a viscous coupling structure. It is a figure which shows the torque limiter using a magnetic coupling structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine starter 3 Transmission mechanism 3a Starter pulley 3b Crank pulley 5 Engine 5a Crankshaft 5b Sprocket 7 DC starter motor 9 Auxiliary machine 11 Torque limiter

Claims (4)

A starter motor that supplies starting torque to the crankshaft of the engine;
A transmission mechanism for transmitting the starting torque supplied by the starter motor to a crankshaft of the engine,
An engine starter characterized in that the transmission mechanism is provided with a torque limiter that limits the start torque transmitted to the crankshaft of the engine to a predetermined value or less. The engine starting device according to claim 1,
In the transmission mechanism, a crank pulley is connected to a crankshaft of the engine, a starter pulley is connected to a drive shaft of the starter motor, and the crank pulley and the starter pulley are connected via a belt. An engine starter characterized by. The engine starting device according to claim 2,
The engine starter characterized in that the torque limiter is interposed between a drive shaft of the starter motor and the starter pulley or between a crankshaft of the engine and the crank pulley. The engine starting device according to any one of claims 1 to 3,
The engine starter characterized in that the starter motor is a DC motor.

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