JP4265543B2 - Always mesh starter - Google Patents

Description

  The present invention relates to a constantly meshing starter in which a pinion is constantly meshed with a ring gear of an engine, and is particularly suitable for an idle stop system that automatically controls stop and restart of an engine.

  In recent years, engine control systems (also called idle stop systems, eco-run systems, etc.) that automatically control engine stop and restart have been gradually adopted. This system, for example, automatically stops the engine when the vehicle is temporarily stopped due to an intersection or traffic jam, and automatically restarts the engine when starting, which is effective in improving the fuel efficiency of the vehicle or improving exhaust emissions. .

  As an example of a starter employed in the above system, a belt-driven starter that starts an engine by belt drive is known. As shown in FIG. 4, this starting device includes a starter pulley 100 that is always connected to a crank pulley on the engine side via a belt, and transmits the rotational force of the motor 110 from the starter pulley 100 to the crank pulley by belt transmission. The engine is started, and a mechanical one-way clutch 120 is incorporated in order to prevent overrun after the engine is started (the motor 110 is rotated by the rotation of the engine).

However, in the starter described above, for example, when the engine rotates in reverse on an uphill, the one-way clutch 120 is connected, so that the rotation of the engine is transmitted to the motor 110 side via the clutch 120. The At this time, since the rotational speed is doubled by the speed reducer 130 (planetary gear speed reduction device) connected to the rotation shaft of the motor 110, a great stress is applied to the motor 110.
Therefore, a starter incorporating an electromagnetic clutch has been proposed in order to completely disconnect the engine and the motor after the engine is started (see Patent Document 1).
JP 2001-342935 A

However, in the starter described in the above-mentioned Patent Document 1, the impact torque generated at the start of engine start and the sudden torque fluctuation from the engine are directly transmitted to the electromagnetic clutch, so that clutch slip may occur. is there. For this reason, it is necessary to enlarge the electromagnetic clutch so as to be able to cope with an excessive torque, and there is a problem that mountability to a vehicle is deteriorated.
The present invention has been made based on the above circumstances, and an object thereof is to provide an always-mesh starter having an electromagnetic clutch capable of intermittently transmitting torque between a motor and a pinion and capable of reducing the size of the electromagnetic clutch. Is to provide.

(Invention of Claim 1)
The constant mesh starter of the present invention includes a motor that generates rotational force, an output shaft through which rotation of the motor is transmitted via a speed reducer, and is supported by the output shaft and is always meshed with an engine ring gear. A pinion, an electromagnetic clutch that intermittently transmits torque between the motor and the pinion, and an impact torque that is provided between the electromagnetic clutch and the pinion and is generated between the electromagnetic clutch and the pinion and a sudden torque fluctuation transmitted from the engine The speed reducer meshes with both gears, a sun gear provided on the armature shaft of the motor, an internal gear disposed concentrically with the sun gear and rotatably provided. The planetary gear rotates and revolves when the sun gear rotates while the rotation of the internal gear is constrained. Is transmitted to the output shaft, and the electromagnetic clutch has a clutch plate connected directly or indirectly to the internal gear, and the clutch plate is attracted by electromagnetic force to attract the internal gear. Torque can be transmitted by restraining the rotation, and the clutch plate is disconnected by the disappearance of the electromagnetic force, and the rotation of the internal gear is allowed to block the torque transmission.

According to said structure, transmission of a torque can be interrupted | blocked between a motor and a pinion by turning off an electromagnetic clutch after engine starting. As a result, for example, even when the engine rotates in reverse on an uphill or the like, the rotation of the engine is not transmitted to the motor, and a great amount of stress can be prevented from being applied to the motor.
In addition, since the impact reducing device is provided between the electromagnetic clutch and the pinion, the impact reducing device can reduce the impact torque generated at the start of engine start and the sudden engine torque fluctuation. As a result, excessive torque is not applied to the electromagnetic clutch, and the electromagnetic clutch can be reduced in size, and the entire starter can be reduced in size and weight.
Furthermore, when the rotation of the internal gear is constrained by the electromagnetic clutch when the engine is started, the rotation of the motor is transmitted from the sun gear to the planetary gear, and the planetary gear revolves while rotating to output the revolution motion. The pinion rotates by being transmitted to the shaft.
When the engine is started, the pinion that is always meshed with the ring gear is rotated by the engine, so that the rotation of the pinion is transmitted to the output shaft, and the planetary gear rotates by rotating the output shaft. At this time, if the rotation of the internal gear is allowed by the electromagnetic clutch, the internal gear receives the revolving motion of the planetary gear and rotates, so that the rotation of the planetary gear is not transmitted to the sun gear. Torque transmission to the motor side is interrupted.

(Invention of Claim 2 )
2. The constant mesh starter according to claim 1, wherein the impact mitigating device is disposed on an outer periphery of the output shaft, and the pinion is fitted to the outer periphery of the output shaft so as to be relatively rotatable via a bearing, and the impact mitigating device is provided. It is connected to the output shaft through a device.
As a result, when the engine is started, the motor torque after deceleration is transmitted from the output shaft to the pinion via the impact mitigation device, and the impact torque generated during the torque transmission is reduced by the impact mitigation device. On the other hand, after the engine is started, when the torque fluctuation of the engine is transmitted from the pinion to the output shaft, it is reduced by the impact mitigation device.

(Invention of Claim 3 )
According to a second aspect of the present invention, the electromagnetic clutch includes an exciting coil that generates an electromagnetic force, and the exciting coil is disposed on the outer peripheral side of the shock absorbing device.
According to this configuration, since the shock absorbing device and the electromagnetic clutch can be arranged concentrically on the outer periphery of the output shaft, the arrangement space for the shock absorbing device and the electromagnetic clutch can be reduced, and as a result, the electromagnetic clutch and the shock absorbing device It is possible to avoid an increase in the size of the starter due to the provision of.

(Invention of Claim 4 )
The constant mesh starter according to any one of claims 1 to 3 , wherein a torque limiter capable of interrupting transmission of excessive torque is provided in a torque transmission path from the motor to the pinion.
As a result, when an excessive torque exceeding the capacity of the impact mitigation device is applied, the torque limiter is activated to cut the excessive torque, so that the excessive torque is not applied to the electromagnetic clutch, and the electromagnetic clutch can be reduced in size and weight. .

(Invention of Claim 5 )
In constant-mesh type starter according to claim 1, the clutch plate of the electromagnetic clutch, characterized in that it is connected to the internal gear through a torque limiter according to claim 4. In this case, since the torque limiter is provided between the clutch plate and the internal gear, even if the clutch plate is attracted by electromagnetic force, if excessive torque is applied to the reduction gear, the torque limiter is activated, When the coupling state between the clutch plate and the internal gear is released and the internal gear rotates, it can be avoided that an excessive torque is applied to the electromagnetic clutch.

(Invention of Claim 6 )
Any one of the constant mesh starters described in claims 1 to 5 is used for an engine automatic stop / restart system that automatically controls stop and restart of the engine.
In the starter of the present invention, since the pinion does not detach from the ring gear of the engine after the engine is started and is always meshed, when used in the engine automatic stop / restart system, when the engine is restarted, Unlike a normal pinion dive starter, it is not necessary to move the pinion to mesh with the ring gear, and the engine can be restarted in a short time.

  The best mode for carrying out the present invention will be described in detail with reference to the following examples.

FIG. 1 is a cross-sectional view of the starter 1, and FIG. 2 is a partially enlarged cross-sectional view of the starter 1.
The starter 1 according to the first embodiment automatically stops / restarts the engine 2 that automatically stops the engine 2 (see FIG. 3) when the vehicle temporarily stops due to an intersection or traffic jam, and automatically restarts the engine 2 when starting. Applies to starting systems (called idle stop systems).

  As shown in FIG. 1, the starter 1 includes a motor 3 that generates a rotational force, an electromagnetic switch 5 that opens and closes a main contact 4 (see FIG. 3) provided in an energization circuit of the motor 3, and a rotation of the motor 3. Is transmitted via the reduction gear 6, the pinion 8 supported by the output shaft 7, the electromagnetic clutch 9 that intermittently transmits torque between the motor 3 and the output shaft 7, and excessive torque The torque limiter 10 that cuts off the transmission of the torque and the impact mitigation device 11 that mitigates the impact torque and the like generated at the start of torque transmission.

The motor 3 is a well-known DC motor including a field 12 for generating magnetic flux, an armature 14 having a commutator 13, a brush 15 disposed on the commutator 13, and the like. And fixed to the front housing 17.
The field 12 is configured by arranging a plurality of permanent magnets 12b at equal intervals in the circumferential direction on the inner periphery of a yoke 12a forming a magnetic circuit. A field coil can be used instead of the permanent magnet 12b.
The armature 14 is configured by winding an armature coil 14c around an armature core 14b fixed to the armature shaft 14a, and both ends of the armature shaft 14a are rotatably supported.

As shown in FIG. 3, the electromagnetic switch 5 has a built-in solenoid 5a energized from the battery 19 via the starter relay 18, and opens and closes the main contact 4 using the electromagnetic force generated by energizing the solenoid 5a. To do. The electromagnetic switch 5 is disposed outside the motor 3 in the radial direction and is fixed to the center housing 16.
The starter relay 18 is closed by energizing the relay coil 18a when the driver puts the start switch 20 into the ST position (see FIG. 3) when the engine is first started. At the time of restart, the relay coil 18a is energized through the ECU 21 (see FIG. 3) for idling stop that controls the automatic stop and restart of the engine 2.

  As shown in FIG. 2, the reduction gear 6 includes a sun gear 6 a formed on the armature shaft 14 a of the motor 3, an internal gear 6 b disposed concentrically with the sun gear 6 a and rotatably provided. This is a well-known planetary gear reducer composed of a plurality of planetary gears 6c meshing with both gears 6a, 6b. In the reduction gear 6, when the armature 14 rotates in a state where the rotation of the internal gear 6 b is restricted, the rotation of the armature 14 is transmitted from the sun gear 6 a to the planetary gear 6 c, and the planetary gear 6 c rotates. However, the revolution motion is transmitted to the output shaft 7 by revolving around the sun gear 6a.

The output shaft 7 is disposed coaxially with the armature shaft 14 a of the motor 3, one end side is rotatably supported by the front housing 17 via the bearing 22, and the other end side is armature shaft 14 a via the speed reduction device 6. It is connected to.
The pinion 8 is fitted to the outer periphery of the output shaft 7 through a bearing 23 so as to be relatively rotatable, and is always meshed with the ring gear 24 of the engine 2.

  The electromagnetic clutch 9 includes an exciting coil 9a energized from a battery 19 via a starter relay 18, a housing 9b that forms a magnetic circuit around the exciting coil 9a, and an axial direction facing the end face of the housing 9b ( The clutch plate 9c is movable in the left-right direction in FIG. The clutch plate 9c is connected to the torque limiter 10 via an elastic material 25 such as rubber, and is provided so as to be rotatable integrally with the torque limiter 10. The electromagnetic clutch 9 is allowed to rotate the clutch plate 9c by maintaining a predetermined gap (for example, 0.3 mm) between the end face of the housing 9b and the clutch plate 9c when the exciting coil 9a is not energized. Has been. On the other hand, when an electromagnetic force is generated by energizing the exciting coil 9a, an attractive force acts between the housing 9b and the clutch plate 9c, and the clutch plate 9c is attracted to the end surface of the housing 9b, thereby causing the clutch plate 9c to be attracted. Is restricted.

  As shown in FIG. 2, the torque limiter 10 is rotatably supported by the center housing 16 via a ball bearing 26 and is connected to the clutch plate 9c via an elastic member 25 of the electromagnetic clutch 9. A rotation disk 10b that is rotationally restricted by the frictional force with respect to the center plate 10a and connected to the internal gear 6b of the speed reducer 6, and the rotation disk 10b is pressed against the center plate 10a to generate the frictional force. It is comprised from the disc spring 10c to be made.

  The torque limiter 10 has an excessive torque exceeding the stationary torque of the rotary disk 10b in a state where the rotation of the center plate 10a is constrained, that is, in a state where the clutch plate 9c of the electromagnetic clutch 9 is attracted to the end surface of the housing 9b. When applied to the speed reducer 6, the rotating disk 10b slides (rotates) with respect to the center plate 10a, whereby the internal gear 6b is allowed to rotate and excessive torque can be absorbed.

The impact mitigation device 11 includes a rotating member 11a that is connected to the pinion 8 and rotates integrally with the pinion 8, a rotating member 11b that is serrated to the outer periphery of the output shaft 7 and rotates integrally with the output shaft 7, The elastic member 11c is made of rubber or the like interposed between the rotating members 11a and 11b. As shown in FIG. 1, a plurality of elastic members 11c are used in series via an intermediate member 11d.
For example, the impact reducing device 11 absorbs the impact torque and the torque fluctuation by deforming (bending) the elastic member 11c with respect to the impact torque generated at the time of starting the engine or a sudden torque fluctuation received from the engine 2. be able to.

Next, the operation and effect of the starter 1 will be described.
When the engine 2 is restarted, the ECU 21 for idling stop energizes the solenoid 5a of the electromagnetic switch 5 and the exciting coil 9a of the electromagnetic clutch 9 through the starter relay 18 simultaneously. At this time, the timing at which the electromagnetic clutch 9 is actuated (the clutch plate 9c is attracted to the end face of the housing 9b) is earlier than the timing at which the main contact 4 of the motor 3 is closed by the electromagnetic switch 5. This is because the gap set between the housing 9b of the electromagnetic clutch 9 and the clutch plate 9c is a few millimeters (for example, 0.3 mm) and is extremely small compared to the opening / closing stroke of the main contact 4. . Even if the timing at which the main contact 4 is closed and the timing at which the clutch plate 9c is attracted to the end face of the housing 9b are the same, the moment of inertia of the motor 3 will not occur until the motor 3 actually starts rotating. Since it takes time to start up, as a result, the electromagnetic clutch 9 operates earlier than the rotation start of the motor 3.

  When the electromagnetic clutch 9 is actuated, the rotation of the internal gear 6b connected to the clutch plate 9c via the torque limiter 10 is restricted, so that torque transmission from the motor 3 to the output shaft 7 becomes possible. As a result, the rotation of the motor 3 is transmitted to the output shaft 7 via the speed reduction device 6, and the rotation of the output shaft 7 is transmitted from the pinion 8 to the ring gear 24 to crank the engine 2. At this time, an impact torque is generated when torque is transmitted from the pinion 8 to the ring gear 24 in order to start the engine 2 having a large inertial energy. This impact torque is effectively absorbed by the impact relaxation device 11 provided between the pinion 8 and the output shaft 7.

  When the engine 2 is restarted, energization of the solenoid 5a of the electromagnetic switch 5 and the exciting coil 9a of the electromagnetic clutch 9 is simultaneously stopped. As a result, energization from the battery 19 to the motor 3 is stopped, the rotation of the armature 14 is stopped, and the clutch plate 9c of the electromagnetic clutch 9 is pulled away from the end surface of the housing 9b by the restoring force of the elastic member 25 to be rotatable. Thus, rotation of the internal gear 6b connected to the clutch plate 9c via the torque limiter 10 is allowed. As a result, the torque transmission path is interrupted between the motor 3 and the output shaft 7.

When the engine 2 is started, the pinion 8 that is always meshed with the ring gear 24 is rotated by the engine 2, but the clutch plate 9 c is disconnected as described above, and the torque between the motor 3 and the output shaft 7 is reduced. Since the transmission path is blocked, the rotation of the pinion 8 is not transmitted to the motor 3 side. Therefore, even when the engine 2 is reversely rotated due to an engine stall on an uphill or the like, the rotation of the engine 2 is not accelerated and transmitted to the motor 3, and it is possible to prevent a great stress from being applied to the motor 3.
Furthermore, even when it is necessary to restart immediately before the engine 2 automatically stops (in a state where the engine 2 rotates with its own inertia), the electromagnetic clutch 9 operates and starts before the motor 3 starts rotating. Since the impact torque generated at the time can be absorbed by the impact relaxation device 11, the starter 1 can be operated and the engine 2 can be restarted even during engine rotation.

  As described above, the starter 1 of the present embodiment can absorb the impact torque generated when the engine is started, the sudden torque fluctuation of the engine 2, and the like by the impact relaxation device 11. Further, an excessive impact that cannot be absorbed by the impact relaxation device 11 can be cut by the torque limiter 10. As a result, excessive torque is not applied to the electromagnetic clutch 9 and clutch slip does not occur. Therefore, the electromagnetic clutch that adsorbs the clutch plate 9c as compared with the known technique described in Patent Document 1 described above. Accordingly, the electromagnetic clutch 9 can be reduced in size and weight.

It is sectional drawing of a starter. It is an expanded sectional view which shows the structure of a reduction gear and a torque limiter. It is an electric circuit diagram of a starter. It is sectional drawing of the belt type starter concerning a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Starter 2 Engine 3 Motor 6 Reduction gear 6a Sun gear 6b Internal gear 6c Planetary gear 7 Output shaft 8 Pinion 9 Electromagnetic clutch 9a Excitation coil 9c Clutch plate 10 Torque limiter 11 Impact mitigation device 14a Armature shaft 24 Ring gear

Claims (6)

A motor that generates rotational force;
An output shaft through which the rotation of the motor is transmitted via a speed reducer;
A pinion supported by this output shaft and always meshed with the ring gear of the engine;
An electromagnetic clutch for intermittently transmitting torque between the motor and the pinion;
In the always-mesh starter provided between the electromagnetic clutch and the pinion, and provided with an impact mitigation device that mitigates an impact torque generated at the start of torque transmission and an abrupt torque fluctuation transmitted from the engine ,
The speed reducer is composed of a sun gear provided on the armature shaft of the motor, an internal gear disposed concentrically with the sun gear and rotatably provided, and a planetary gear meshing with both gears, A planetary gear reduction device in which the planetary gear rotates and revolves when the sun gear rotates while the rotation of the internal gear is constrained, and the revolving motion is transmitted to the output shaft. ,
The electromagnetic clutch has a clutch plate that is directly or indirectly connected to the internal gear, and can transmit torque by attracting the clutch plate by electromagnetic force and restricting the rotation of the internal gear. And the transmission of torque is cut off by allowing the internal gear to rotate by separating the clutch plate by the disappearance of the electromagnetic force . The always-mesh starter according to claim 1 ,
The impact mitigation device is disposed on the outer periphery of the output shaft,
The pinion is fitted to the outer periphery of the output shaft so as to be relatively rotatable via a bearing, and is connected to the output shaft via the impact mitigating device. In the always meshing starter according to claim 2 ,
The electromagnetic clutch has an exciting coil that generates electromagnetic force, and the exciting coil is disposed on the outer peripheral side of the shock absorbing device. In the always meshing starter according to any one of claims 1 to 3 ,
A constant mesh starter characterized in that a torque limiter capable of interrupting transmission of excessive torque is provided in a torque transmission path from the motor to the pinion. The always-mesh starter according to claim 1 ,
A clutch plate of the electromagnetic clutch is connected to the internal gear via a torque limiter according to claim 4 , and is a constant mesh starter. Any one of the constantly meshing starters according to claims 1 to 5 ,
A constant mesh starter used in an automatic engine stop / restart system for automatically controlling engine stop and restart.

Images