JP6160491B2 - Starter - Google Patents

Description

  The present invention relates to a starter that transmits torque generated by a motor to an engine to start the engine.

  In recent years, an increasing number of vehicles are equipped with an idle stop function from the viewpoint of carbon dioxide emission regulation and fuel efficiency improvement. There are various types of starter for idling stop, such as a gear drive method and a belt drive method, and what is called a constant meshing method is when the one-way clutch provided on the vehicle side (engine side) is not idling. The torque transmission path between the motor and the engine is always connected.

  For example, in a belt drive type starter, a crank pulley provided on the vehicle side and a starter pulley provided on the starter are connected via a belt. When starting the engine, the torque of the starter is transmitted to the engine via the belt to start the engine. Further, after the engine is started, transmission of torque from the engine to the motor is interrupted by a one-way clutch provided in a crank pulley on the vehicle side (see, for example, Patent Document 1).

  However, if the one-way clutch breaks down for some reason and the one-way clutch is always on (locked), the engine rotation is transmitted to the starter via the belt. In this case, the motor armature has a rotational speed that is the magnitude obtained by multiplying the rotational speed of the engine by the pulley ratio (crank pulley diameter / starter pulley diameter) and the internal reduction ratio of the speed reducer provided inside the starter. It is assumed that the motor is rotated at a high speed of tens of thousands to hundreds of thousands of rpm because it is transmitted.

  Such a rotational speed greatly exceeds the rotational speed of the motor obtained by power supply from the battery when starting the engine, and it is very difficult to avoid centrifugal damage of the motor. When the motor is centrifugally damaged, the motor components (for example, commutator, coil, brush holder, etc.) are scattered inside the starter, and in the worst case, the damaged part inside the starter may be locked due to the factor. In addition, even if it is not completely locked, since the engine (crank pulley) and the starter are always connected via the belt, a large loss torque is generated due to the sliding resistance of the damaged parts inside the starter. The situation is also conceivable.

  When the engine continues to run without being completely locked, the torque increases due to the reduction ratio between the starter and the crank pulley (that is, the product of the pulley ratio and the internal reduction ratio). For this reason, the loss torque due to the damaged parts becomes a magnitude that cannot be ignored for the engine, and if the vehicle is running, it is possible that the running is hindered by a sudden decrease in the engine torque.

In addition, the belt may be damaged due to the complete lock state or the loss torque becoming very large.
For this reason, even when a one-way clutch failure or the like occurs, it is desired to eliminate the influence on traveling as much as possible and enable movement (retreat traveling) to a safe place.

JP 2006-118494 A

  The present invention has been made to solve the above-described problems, and its purpose is to always connect a torque transmission path between the motor and the engine when the one-way clutch is not idling. In the starter, even if a one-way clutch failure or the like occurs, there is provided a fail-safe function that enables the vehicle to evacuate by eliminating the influence on the travel as much as possible.

  According to the first invention of the present application, the starter transmits the torque generated by the motor to the engine and starts the engine. The torque transmission from the engine to the motor is interrupted by the idling of the one-way clutch arranged on the engine side. When the one-way clutch is not idling, the torque transmission path is always between the motor and the engine. Are connected.

  Further, the starter includes a fail-safe portion that interrupts transmission of torque from the engine to the motor by breaking when the one-way clutch does not operate normally and torque is transmitted from the engine. The fail-safe portion is provided by reducing the rotation radius in any of the rotating bodies that exist between the motor and the output end of the torque of the starter and transmit torque.

  As a result, the fail-safe portion is broken when torque is transmitted from the engine to the motor without the one-way clutch operating normally. For this reason, since the centrifugal breakage of the motor can be prevented, the inside of the starter can be prevented from being locked, and the loss torque generated inside the starter can be suppressed. As a result, even if a one-way clutch failure or the like occurs, the engine torque can be suppressed and the influence on the travel can be minimized, so that the vehicle can be retreated.

According to the second invention subordinate to the first invention, the starter includes the speed reducer, the speed reducer exists between the motor and the output end of the starter, and amplifies and transmits the torque generated by the motor. A plurality of reduction gears are provided in a torque transmission path from the motor to the output end of the starter.
When a plurality of reduction gears are provided, torque amplification is large and loss torque is likely to increase, so that the effect of suppressing a decrease in engine torque due to breakage of the fail-safe portion is remarkably obtained.

According to the third invention subordinate to the second invention, the fail-safe portion is provided in a portion for transmitting torque between the two speed reducers in the torque transmission path from the motor to the output end of the starter.
If a fail-safe portion is provided between the output end of the starter and the speed reducer near the output end of the starter, there is a possibility that a component (for example, a starter pulley) that forms the output end of the starter may fall off. Therefore, by providing a fail-safe portion between the two speed reducers, it is possible to avoid the parts that make up the output end from falling off.

  According to the fourth invention subordinate to the third invention, the second reducer provided on the side closer to the output end of the starter with respect to transmission of torque generated by the motor among the two reducers is a planetary gear reducer. The fail safe part is a cylindrical part that is coaxially and integrally provided with the sun gear of the second reduction gear and rotates. And the rotation radius of a fail safe part is below the radius of the root of a sun gear.

  When providing a fail-safe part between two reducers, if the sun gear of the second reducer is more likely to break than the fail-safe part, the sun gear breaks due to torque transmission from the engine to the starter, and the teeth There is a possibility that the second speed reducer may be locked due to the biting. Therefore, the fail safe part is more easily broken than the sun gear by setting the rotation radius of the fail safe part to be equal to or less than the radius of the root of the sun gear. As a result, it is possible to avoid the biting of teeth due to damage to the sun gear and to eliminate the possibility that the second reduction gear will be locked.

1 is an overall configuration diagram of a starter (Example 1). FIG. It is a whole block diagram of a starter (Example 2). It is a whole block diagram of a starter (Example 2).

  The starter of the embodiment will be described based on examples.

[Configuration of Example 1]
The starter 1 of Example 1 is demonstrated based on FIG.
The starter 1 employs a so-called belt drive system, and is installed in an engine room of an idle stop vehicle, for example, and transmits torque generated by the motor 2 to an engine (not shown) to start the engine. .

  That is, according to the starter 1, a crank pulley (not shown) provided on the vehicle side (engine side) and a starter pulley 3 provided on the starter 1 are connected via a belt (not shown). ing. When starting the engine, the torque of the starter 1 is transmitted to the engine via the belt to start the engine. In addition, after the engine is started, transmission of torque from the engine to the motor 2 is interrupted by the idling of a one-way clutch (not shown) provided in the crank pulley on the vehicle side. Further, according to the starter 1, the torque transmission path between the motor 2 and the engine is always connected when the one-way clutch is not idling.

Hereinafter, the configuration of the starter 1 will be described.
The starter 1 includes a motor 2, an electromagnetic switch 4, a speed reducer 5, a shock absorber 6, a pulley shaft 7, a starter pulley 3, and the like described below.

  The motor 2 is supplied with electric power from a battery (not shown) and generates torque. The armature 8 includes a field 9 that forms a magnetic field and a commutator 11 on the axis of the armature shaft 10. This is a known DC motor constituted by a brush 13 and the like disposed on the outer periphery of the commutator 11. The field 9 is, for example, a permanent magnet disposed on the inner periphery of the yoke 14 that forms the magnetic circuit, but a winding that forms an electromagnet instead of the permanent magnet may be adopted as the field 9. .

  The electromagnetic switch 4 has a main contact (not shown) for turning on / off the energization of the motor 2, and opens and closes the main contact by driving the plunger 15 with a magnetic flux generated by energizing a coil (not shown). To do.

  The reducer 5 amplifies and transmits the torque generated by the motor 2 and is provided at two locations in the torque transmission path from the armature shaft 10 of the motor 2 to the starter pulley 3 (hereinafter referred to as torque). In this transmission path, the speed reducer 5 closer to the motor 2 may be referred to as a first speed reducer 17, and the speed reducer 5 closer to the starter pulley 3 may be referred to as a second speed reducer 18.)

  First, the first reduction gear 17 includes a sun gear 20 that is coaxial with the armature shaft 10 on the front side in the axial direction of the armature shaft 10 of the motor 2, and an internal gear that is disposed coaxially with the sun gear 20. 21, a planetary gear 22 that meshes with both the sun gear 20 and the internal gear 21, a planet carrier 24 that supports the planetary gear 22 via a gear shaft 23, and the like. The planet carrier 24 is provided integrally with the output shaft 25 of the first speed reducer 17, and the output shaft 25 rotates integrally with the planet carrier 24 by the revolution of the planet gear 22.

  Next, the second reduction gear 18 includes a sun gear 27 that is coaxial with and integrally formed with the output shaft 25 on the front side in the axial direction of the output shaft 25, an internal gear 28 that is disposed coaxially with the sun gear 27, and the sun gear 27. And a planetary gear 29 that meshes with both the internal gear 28 and a planetary carrier 31 that supports the planetary gear 29 via a gear shaft 30. The planetary carrier 31 is provided integrally with a pulley shaft 7 as an output shaft of the second reduction gear 18, and the pulley shaft 7 rotates integrally with the planetary carrier 31 by the revolution of the planetary gear 29.

The impact absorbing device 6 absorbs an impact when an excessive impact is applied to the speed reducer 5.
Specifically, the shock absorber 6 includes a center case 35 whose rotation is restricted by the housing 34, a fixed plate 36 whose rotation is restricted by the center case 35, and a rotation plate arranged between the center case 35 and the fixed plate 36. 37, and a spring washer 38 that presses the fixed plate 36.

The rotating plate 37 is engaged with the internal gear 21 of the first reduction gear 17 and is rotatably arranged with the internal gear 21, and receives the biasing force of the spring washer 38 via the fixed plate 36. That is, the fixed plate 36 is pressed against the rotating plate 37 by the urging force of the spring washer 38, and a frictional force is generated between the rotating plates 36 and 37, and the rotating plate 37 is stopped by this frictional force.
The shock absorbing device 6 absorbs the shock by sliding (rotating) the rotating plate 37 against the frictional force when the reverse rotation shock is transmitted from the engine side to the output shaft 25.

The pulley shaft 7 rotates while holding the starter pulley 3 on the outer peripheral side, holds the starter pulley 3 on the outer peripheral side by direct spline fitting, and transmits the torque of the motor 2 amplified by the speed reducer 5. Has been rotated.
The pulley shaft 7 is rotatably supported by the housing 34 via the bearing 40. In addition, a spring 41 is mounted between the spline fitting and the bearing 40 to suppress the unbalanced load accompanying the displacement of the belt in the axial direction.

  The starter pulley 3 forms an output end of torque of the starter 1, is held at the front end of the pulley shaft 7 protruding forward in the axial direction of the housing 34, and rotates integrally with the pulley shaft 7.

With the above configuration, the starter 1 operates as follows.
First, when the coil of the electromagnetic switch 4 is energized, the plunger 15 moves and the main contact is closed. Thereby, electric power is supplied from the battery to the motor 2, and torque is generated from the motor 2. The torque generated by the motor 2 is decelerated in two stages by the first and second reducers 17 and 18, amplified and transmitted to the pulley shaft 7, and the starter pulley 3 rotates integrally with the pulley shaft 7. . Then, torque is transmitted from the starter pulley 3 to the crank pulley via the belt, and the crankshaft rotates to start the engine.

Furthermore, the starter 1 includes the following fail-safe unit 43 as a characteristic configuration.
The fail-safe portion 43 is a portion that interrupts transmission of torque from the engine to the motor 2 by breaking when the one-way clutch provided on the vehicle side does not operate normally and torque is transmitted from the engine. is there. Further, the fail safe unit 43 is provided by reducing the rotation radius in any of the rotating bodies that exist between the motor 2 and the torque output end (starter pulley 3) of the starter 1 and transmit torque. Yes.

  Here, the fail safe part 43 of the first embodiment is provided by reducing the rotation radius of the output shaft 25 of the first reduction gear 17. That is, the fail safe portion 43 is a cylindrical portion in which the rotation radius of the output shaft 25 that transmits torque between the first and second reduction gears 17 and 18 is reduced, and is coaxial with the sun gear 27 of the second reduction gear 18. It is provided integrally and rotates. The rotation radius of the fail safe portion 43 is set to be equal to or less than the radius of the tooth bottom of the sun gear 27.

[Effect of Example 1]
The starter 1 of the first embodiment is always connected to the torque transmission path between the motor 2 and the engine except when the one-way clutch is idling, and includes the following fail-safe unit 43. That is, the fail safe unit 43 blocks the transmission of torque from the engine to the motor 2 by breaking when the one-way clutch does not operate normally and torque is transmitted from the engine. The fail safe unit 43 is provided by reducing the rotation radius on the output shaft 25 of the first reduction gear 17.

When the fail-safe portion 43 is not provided, if the motor 2 is centrifugally damaged due to a failure of the one-way clutch, the starter 1 is locked or a large loss torque is generated inside the starter 1 due to the damaged parts. There is a fear.
Therefore, the fail safe portion 43 is provided, and the fail safe portion 43 is broken when the torque is transmitted from the engine without causing the one-way clutch to operate normally and the motor 2 is centrifugally damaged.

  As a result, even if the motor 2 is centrifugally damaged and a loss torque is generated in the motor 2, the fail safe portion 43 is broken and the torque transmission path is interrupted. Therefore, the starter pulley 3 and the pulley shaft 7 are It can rotate without being affected by loss torque. For this reason, even if a one-way clutch failure or the like occurs, the engine torque can be suppressed and the influence on the travel can be minimized, so that the vehicle can be retreated.

In addition, according to the starter 1, the speed reducer 5 is provided in two parts of the first and second speed reducers 17 and 18 in the torque transmission path from the motor 2 to the starter pulley 3.
When two speed reducers 5 are provided, torque amplification is large and loss torque tends to be large, so that the effect of suppressing a decrease in engine torque due to breakage of fail-safe portion 43 is significantly obtained.

Further, the fail safe part 43 is provided on the output shaft 25 of the first reduction gear 17.
If the fail-safe portion 43 is provided between the starter pulley 3 that is the torque output end of the starter 1 and the second speed reducer 18, the starter pulley 3 may fall off. Therefore, by providing the fail safe portion 43 on the output shaft 25 between the first and second reduction gears 17 and 18, the starter pulley 3 can be prevented from falling off.

The output shaft 25 is provided coaxially and integrally with the sun gear 27 of the second reduction gear 18 and rotates. The rotation radius of the fail safe portion 43 is equal to or less than the radius of the tooth bottom of the sun gear 27.
When the fail safe portion 43 is provided on the output shaft 25, if the sun gear 27 is more easily broken than the fail safe portion 43, the sun gear 27 is broken by torque transmission from the engine to the starter 1, and the teeth are caught. As a result, the second reducer 18 may be locked.

  Therefore, the fail safe portion 43 is more easily broken than the sun gear 27 by setting the rotation radius of the fail safe portion 43 to be equal to or less than the radius of the tooth bottom of the sun gear 27. Thereby, it is possible to avoid the biting of teeth due to the damage of the sun gear 27 and to eliminate the possibility that the second speed reducer 18 is locked.

[Example 2]
According to the starter 1 of the second embodiment, as shown in FIGS. 2 and 3, the fail safe portion 43 is provided on the pulley shaft 7.
If the fail safe part 43 is provided on the pulley shaft 7, the fail safe part 43 is provided between the starter pulley 3 and the second speed reducer 18, rather than when the fail safe part 43 is provided on the output shaft 25. The possibility of the starter pulley 3 falling off increases. Therefore, when the fail-safe portion 43 is provided on the pulley shaft 7, for example, the same position as the bearing 40 in the axial direction (see FIG. 2) or rearward in the axial direction from the bearing 40 (see FIG. 3). Is preferably provided.

[Modification]
The mode of the starter 1 is not limited to the embodiment, and various modifications can be considered.
For example, according to the starter 1 of the embodiment, the speed reducer 5 is provided with the first and second speed reducers 17 and 18, but only one speed reducer 5 may be provided. Three or more may be provided. Further, according to the starter 1 of the embodiment, both the first and second speed reducers 17 and 18 are planetary gear speed reducers, but the speed reducer 5 having a structure other than the planetary gears may be employed. Furthermore, the part which provides the fail safe part 43 is not limited to an Example, You may provide the fail safe part 43 other than the output shaft 25 of the 1st reduction gear 17, and the pulley shaft 7. FIG.

1 Starter 2 Motor 3 Starter pulley (output end) 43 Fail safe part

Claims (4)

The torque generated by the motor (2) is transmitted to the engine to start the engine, and the one-way clutch disposed on the engine side is idled to transmit torque from the engine to the motor (2). In the starter (1) in which the torque transmission path between the motor (2) and the engine is always connected, except when the one-way clutch is idled,
The one-way clutch does not operate normally, and is provided with a fail-safe portion (43) for breaking transmission of torque from the engine to the motor (2) by breaking when torque is transmitted from the engine. ,
The fail safe part (43) reduces the radius of rotation in any of the rotating bodies that exist between the motor (2) and the torque output end (3) of the starter (1) and transmit torque. The starter (1) characterized by being provided. The starter (1) according to claim 1,
A reduction gear (5) that exists between the motor (2) and the output end (3) of the starter (1) and that amplifies and transmits the torque generated by the motor (2);
The reducer (5) is provided with a plurality of torque transmission paths from the motor (2) to the output end (3) of the starter (1). Starter (1) according to claim 2,
The fail safe portion (43) is a portion that transmits torque between the two speed reducers (5) in a torque transmission path from the motor (2) to the output end (3) of the starter (1). A starter (1) characterized in that it is provided. Starter (1) according to claim 3,
Of the two speed reducers (5), the second speed reducer (18) provided on the side close to the output end (3) of the starter (1) with respect to transmission of torque generated by the motor (2) is a planetary gear. A reducer,
The fail safe part (43) is a cylindrical part that rotates coaxially and integrally with the sun gear (27) of the second reduction gear (18),
The starter (1), wherein a rotation radius of the fail safe part (43) is equal to or less than a radius of a tooth bottom of the sun gear.

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