JP4174830B2 - Always-on starter - Google Patents

Description

  The present invention relates to an always-connected starter in which an engine and a starter (starting device) are always connected via a one-way clutch.

(Conventional technology)
An always-on starter used for an idle stop system or the like is known. This always-connected starter always connects the crankshaft of the engine and the output shaft of the starter via a one-way clutch (one-way clutch). The one-way clutch transmits rotational power only from the output shaft to the direction of the crankshaft, and prevents the starter from being rotationally driven by the rotational torque of the crankshaft, so-called rotation. Normally, the crankshaft and the output shaft are connected via power transmission means using a belt or gear and a one-way clutch. The power transmission means can also serve as a speed reduction means for transmitting the rotation of the starter to the crankshaft (see, for example, Patent Document 1).

(Problems of conventional technology)
During engine operation, the rotational speed of the crankshaft is higher than the rotational speed of the output shaft. During the operation of such an engine, the one-way clutch is idled to prevent the starter from being driven by the rotational torque of the crankshaft. However, even when the one-way clutch is idling, idling torque of the one-way clutch is applied to the output shaft of the starter due to dragging of the one-way clutch, bearings of the one-way clutch, rotational resistance of the rollers, and the like. Here, the idling torque refers to torque transmitted from the output side to the input side when the one-way clutch is idling. For example, the torque is transmitted from the engine to the output shaft of the starter through the idling one-way clutch and reversely rotates the output shaft of the starter.

Therefore, it is necessary to prevent the output shaft of the starter from rotating with the idling torque of the one-way clutch. However, in the technique of the above-described Patent Document 1, the relationship between the idling torque after the engine is started and the fixed torque of the starter. There is no disclosure. The fixed torque is a torque in the rotation direction immediately before the rotation starts. For example, it is the maximum torque at which the output shaft of the starter can be kept stationary.
As the electric motor built in the starter, a direct current motor (DC motor) that supplies power with a brush is used to obtain a large current and a high output. However, when an always-connected starter is configured, as the life of the brush decreases, the armature fixing torque decreases, and the output shaft fixing torque decreases. The fixed torque of the output shaft is also called the fixed torque of the starter. If the fixed torque of the output shaft is smaller than the idling torque of the one-way clutch, the idling torque causes the starter to rotate, causing the armature in the starter to rotate and causing the armature to break. In particular, when a reduction gear is arranged between the output shaft and the armature to decelerate the rotation of the armature and transmit it to the output shaft, the rotation of the output shaft is increased and transmitted to the armature. There is a possibility that the armature will be spun at a high speed, causing the armature to centrifuge.
Japanese Utility Model Publication No. 52-15631

The present invention has been made in view of the above problems, its object is also fixed torque of the output shaft of the starter becomes minimum, to provide a permanent connection starter starter does not turns with.

[ Means of claim 1 ]
In the always-connected starter employing the means of claim 1 , the minimum fixed torque of the armature is set larger than the maximum idling torque of the one-way clutch.
By providing in this way, the minimum fixed torque of the output shaft can be made larger than the maximum idling torque of the one-way clutch. As a result, with such brush is worn, even when the fixed torque of the output shaft of the starter is a minimum, it does not occur inconvenience that the starter is rotated together.

[Means claim 2
The always-connected starter adopting the means of claim 2 sets the minimum armature fixing torque by the armature fixing torque at the time of the life of the brush of the electric motor.

[Means of claim 3 ]
Always-starter that employs the third aspect, the driving wheel of the one-way clutch is mounted on the output shaft, in which a driven wheel of the crankshaft and the one-way clutch is power transmission through the power transmission means.

[Means of claim 4 ]
The always connected starter employing the means of claim 4 includes a belt and a pulley as power transmission means.

[Means of claim 5 ]
The always-connected starter employing the means of claim 5 includes a plurality of gears as power transmission means.
When using power transmission means by meshing multiple gears, load in the direction orthogonal to the axial direction is not applied to the one-way clutch or output shaft, so without considering power transmission means by meshing multiple gears The maximum idling torque of the one-way clutch and the minimum fixed torque of the output shaft can be set.

In the always-connected starter according to the embodiment of the present invention, the crankshaft of the engine and the output shaft of the starter are always connected via a one-way clutch that transmits rotational power from the output shaft to only the crankshaft. . Then, the always-starter, than the maximum idling torque of the one-way clutch, fixed minimum torque of the armature of the electric motor of the starter is Ru is set larger.

Always-on connection starter, the fixed minimum torque of the armature, can be a fixed torque of the armature during the life of the brush of the electric motor.
In the always-connected starter, the driving wheel of the one-way clutch is mounted on the output shaft, and the power can be transmitted to the crankshaft and the driven wheel of the one-way clutch via power transmission means including a belt and a pulley.
In the always-connected starter, the driving wheel of the one-way clutch is mounted on the output shaft, and the power can be transmitted to the crankshaft and the driven wheel of the one-way clutch through a power transmission means by meshing a plurality of gears.

A first embodiment will be described with reference to FIGS.
An outline of an engine system employing the always-on starter system in the first embodiment will be described with reference to FIG.
The engine 1 is an internal combustion engine. The engine 1 is mounted on an automobile as a power source of the automobile, for example. This car uses an idle stop system. The control device 10 (ECU) is a control device that executes idle stop control. It is not essential to use an idle stop system. In the always-connected starter system, the crankshaft 2 of the engine 1 and the output shaft 4 of the starter 3 are always connected via the power transmission means 5 and the one-way clutch 6.
The power transmission means 5 of the first embodiment uses two pulleys (a large-diameter pulley 7 and a small-diameter pulley 8) and a belt 9 as an example, and reduces the rotational output of the starter 3 and transmits it to the crankshaft 2. It also serves as a deceleration means.
In addition, the one-way clutch 6 of the first embodiment is disposed between the power transmission means 5 and the starter 3, specifically, between the small-diameter pulley 8 and the output shaft 4 of the starter 3. For example, a configuration in which an inner ring as an input side member of the one-way clutch 6 is connected to the output shaft 4 of the starter 3 and an outer ring as an output side member of the one-way clutch 6 is connected to or integrated with the small-diameter pulley 8 can be adopted.

Next, the configuration of the starter 3 in the first embodiment will be described with reference to FIG.
The starter 3 transmits an electric motor 11 that generates a rotational force, a planetary gear reduction device 12 as a reduction mechanism on the starter 3 side that decelerates the rotation of the electric motor 11, and a rotational force that is reduced by the planetary gear reduction device 12. The output shaft 4 is provided. A one-way clutch 6 is mounted on the output shaft 4.

  The electric motor 11 is a DC motor that generates a large drive output. On the outer periphery of the commutator 15 electrically connected to the coil 14 mounted on the armature 13, a power supply brush 16 is disposed. The electric motor 11 includes a plurality of brushes 16. For example, the positive electrode side brush and the negative electrode side brush are provided. The electric motor 11 includes a brush spring that presses the brush 16 toward the commutator 15. A widely known compression coil spring or spiral spring can be used as the brush spring. The brush 16 is always in contact with the commutator 15 by the biasing force of the brush spring. The brush 16 is supported by a brush holder 17 so as to be slidable in the radial direction, and is configured to be pressed against the commutator 15 by an urging force of a brush spring. When the lead 18 connected to the brush 16 is energized from the outside and the stator coil 20 fixed in the yoke 19 on the outer periphery of the armature 13 is energized, a positive rotational force is generated in the armature 13. This positive direction is a direction in which the engine 1 is cranked by the starter 3.

The planetary gear speed reduction device 12 can freely rotate a sun gear 22 formed on one end outer periphery of an armature shaft 21 that is a rotation shaft of the armature 13, a planetary gear 23 that meshes with the sun gear 22, an internal gear 24 that meshes with the planetary gear 23, and the planetary gear 23. It is comprised from the planetary carrier 25 supported by.
The planetary carrier 25 rotatably supports the planetary gear 23 via a pin 26 at the rear end of the output shaft 4, and the planetary gear 23 is rotatably supported via a pin bearing 27 (sliding bearing).
The internal gear 24 is directly connected to the housing 28 or indirectly connected to the housing 28 via an impact absorbing device or the like, so that the rotation is restricted. That is, in the planetary gear speed reduction device 12, the rotation of the internal gear 24 is restricted. For this reason, when the armature 13 rotates, the sun gear 22 rotates and the planetary gear 23 revolves around the outer periphery of the sun gear 22 while rotating. The revolution of the planetary gear 23 is transmitted to the output shaft 4 via the planetary carrier 25.

Next, the configuration of the one-way clutch 6 in the first embodiment will be described with reference to FIGS.
The one-way clutch 6 includes an inner 31 as a driving wheel, an outer 32 as a driven wheel, a roller 33, and the like. The inner 31 is positioned on the input side member, and the outer 32 is positioned on the output side member. The one-way clutch 6 sets the direction in which the output shaft 4 starts the engine 1 as normal rotation. The one-way clutch 6 reverses the rotation in the direction in which the output shaft 4 is driven by the rotation of the engine 1. The one-way clutch 6 allows transmission from the forward rotating inner 31 to the outer 32 and blocks transmission from the reverse rotating outer 32 to the inner 31 by idling. The one-way clutch 6 allows only a state where the rotational speed of the outer 32 is the same as the rotational speed of the inner 31 and a state where the rotational speed of the outer 32 is higher than the rotational speed of the inner 31.
The inner 31 is spline-fitted to the outer periphery of the output shaft 4 and rotates integrally with the output shaft 4.
The outer 32 is coaxially disposed on the outer periphery of the inner 31 via a clutch bearing 34 (rolling bearing). The outer 32 also serves as the small-diameter pulley 8, and a multistage groove 32 a around which the multistage belt 9 is bridged is formed on the outer peripheral surface of the outer 32.

A plurality of recesses are formed on the inner peripheral surface of the outer 32. The recess forms a cam chamber 35 and a spring chamber (not shown) continuous with the cam chamber 35 between the outer 32 and the inner 31. A roller 33 and a clutch spring 36 are disposed inside each recess. The cam chamber 35 is a wedge-shaped space in which one of the rotational directions is narrower than the diameter of the roller 33 and the other of the rotational directions is wider than the diameter of the roller 33, and the roller 33 is always on the narrow side of the cam chamber 35 by the clutch spring 36. It is energized towards. The wide and narrow arrangement of the cam chambers 35 corresponds to the forward and reverse rotation directions of the one-way clutch 6.
For this reason, as shown in FIG. 4A, when the inner 31 rotates in the direction in which the roller 33 rolls toward the narrow side of the cam chamber 35, the roller 33 bites in the narrow space of the cam chamber 35, and the inner 31. Is transmitted to the outer 32. For example, when the engine 1 is cranked by the starter 3 and started, the state shown in FIG.
On the contrary, as shown in FIG. 4B, when the relative rotation difference between the inner 31 and the outer 32 is reversed and the outer 32 rotates in the direction of rolling the roller 33 toward the wide side of the cam chamber 35, the roller 33 Moves against the clutch spring 36 into the wide space of the cam chamber 35 to release the bite, and the outer 32 rotates idly with respect to the inner 31. For example, after the start of the engine 1 by the starter 3 is completed and the engine 1 starts to rotate itself, or during the operation in which the engine 1 is continuously rotating by itself, the state of FIG.

(Description of operation)
When the engine 1 is started for the first time after the engine is stopped, a driver start command is input to the control device 10. The control device 10 commands the starter 3 to be energized, operates the starter 3 and starts the engine 1. When a predetermined idle stop operation condition is satisfied, the control device 10 automatically stops the engine 1. The control device 10 detects an idle stop condition using a sensor. As the idle stop condition, for example, a case where a predetermined time has elapsed after zero vehicle speed is used. The automatic stop of the engine 1 is performed by the control device 10 by, for example, stopping the fuel supply to the engine 1 or stopping the ignition. When a predetermined restart operation condition is satisfied after the engine 1 is automatically stopped by the control device 10, the control device 10 commands the starter 3 to be energized and operates the starter 3 to automatically restart the engine 1. To do. The control device 10 detects a restart condition using a sensor. As the restart condition, for example, a case where an occupant depresses an accelerator pedal is used.
When the control device 10 operates the starter 3, the control device 10 supplies power to the electric motor 11 from a battery (not shown). When the electric motor 11 is supplied with power from the battery, a rotational force is generated in the armature 13, and the rotation is decelerated by the planetary gear reduction device 12 and transmitted to the output shaft 4. Then, the inner 31 rotates in the direction in which the roller 33 rolls toward the narrow side of the cam chamber 35, and the one-way clutch 6 is locked. Thereby, the rotational force decelerated by the planetary gear reduction device 12 is transmitted to the crankshaft 2 of the engine 1 through the one-way clutch 6 and the power transmission means 5 to start the engine 1.

  When the control device 10 determines that the engine 1 is completely exploded, the control device 10 stops power supply to the electric motor 11 and stops the starter 3. On the other hand, when the engine 1 completes explosion and the rotational speed of the outer 32 (small-diameter pulley 8) exceeds the rotational speed of the inner 31, the outer 32 rolls the roller 33 toward the wide side of the cam chamber 35. The one-way clutch 6 is unlocked and the outer 32 idles with respect to the inner 31. As a result, overrun of the armature 13 is prevented.

(Characteristics of Example 1)
During the operation of the engine 1, the rotational speed of the crankshaft 2 is higher than the rotational speed of the output shaft 4. During operation of the engine 1, the one-way clutch 6 is idled to prevent the starter 3 from being driven by the rotational torque of the crankshaft 2. However, even when the one-way clutch 6 is idling, the idling torque of the one-way clutch 6 is applied to the output shaft 4 due to dragging of the one-way clutch 6, rotation resistance of the clutch bearing 34, and the like. While the engine 1 is operating, it is necessary to prevent the output shaft 4 from being rotated by the idling torque of the one-way clutch 6. Here, the idling torque refers to torque transmitted from the output side to the input side when the one-way clutch 6 is idling. For example, the torque is transmitted from the engine 1 to the output shaft 4 of the starter 3 through the idle one-way clutch 6 and reversely rotates the output shaft 4 of the starter 3.

Therefore, in the first embodiment, it is set as the maximum idling torque a transmitted from the crank shaft 2 to the output shaft 4 through the one-way clutch 6, a minimum fixing torque of the output shaft 4 is increased. Here, the fixed torque is torque in the rotation direction immediately before the object starts to rotate. For example, it is the maximum torque at which the output shaft 4 of the starter 3 can maintain a stationary state.
Specifically, in the first embodiment, “the minimum idling torque a (Nm) of the one-way clutch 6 transmitted from the crankshaft 2 to the output shaft 4 via the one-way clutch 6” is smaller than “ the minimum of the armature 13. fixed torque c (Nm) "is set to be larger. Therefore, each part is configured so that the relationship of a <c is established .

(Description of maximum idling torque a)
The idling torque of the one-way clutch 6 can be mainly expressed by the rotational resistance of the clutch bearing 34 and the sliding resistance of the roller 33. Therefore, the idling torque of the one-way clutch 6 is the sum of the rotational resistance of the clutch bearing 34 and the sliding resistance of the roller 33.
The rotational resistance of the clutch bearing 34 varies depending on the sealing force of the seal member 34a in the clutch bearing 34, the amount of grease applied to the clutch bearing 34, the grease viscosity applied to the clutch bearing 34, and the tension (tensile force) of the belt 9. To do.
The sliding resistance of the roller 33 varies depending on the amount of grease applied to the cam chamber 35, the grease viscosity applied to the cam chamber 35, and the urging force of the clutch spring 36 that urges the roller 33. Therefore, the idling torque of the one-way clutch 6 varies between the minimum value and the maximum value.

For this reason, for example, the maximum idling torque a (Nm) of the one-way clutch 6 is given to the clutch bearing 34 by the maximum seal pressing force of the clutch bearing 34, the maximum amount of grease given to the clutch bearing 34, and the clutch bearing 34. The grease viscosity is the maximum viscosity, the tension of the belt 9 is the maximum tension, the amount of grease applied to the cam chamber 35 is the maximum amount, the grease viscosity applied to the cam chamber 35 is the maximum viscosity, and the urging force of the clutch spring 36 is the maximum value. It can be a time value. As described above, the maximum idling torque a of the one-way clutch 6 is determined by the one-way clutch 6 in consideration of the fluctuation factors of the idling torque, such as variations in manufacturing of the one-way clutch 6 and changes with time of the one-way clutch 6. The maximum idling torque possible .

( Description of the minimum fixed torque c of the armature 13)
The fixed torque of the armature 13 can be expressed as the sum of the rotational resistance of the armature bearing 38 that rotatably supports both ends of the armature shaft 21 and the fixed torque of the armature 13 itself.
The rotational resistance of the armature bearing 38 varies depending on the seal pressing force of the armature bearing 38, the amount of grease applied to the armature bearing 38, and the grease viscosity applied to the armature bearing 38.

The fixed torque of the armature 13 itself changes according to the load applied to the brush 16 from the brush spring, as shown by the inclined solid line A in FIG. The load of the brush spring varies depending on the wear of the brush 16.
However, the fixed torque of the armature 13 varies depending on factors other than the load of the brush spring, as indicated by the inclined broken lines A1 and A2 in FIG. For example, the fixed torque of the armature 13 varies depending on the load variation of the brush spring, the variation of the contact point between the brush spring and the brush 16, the error in the length of the brush 16 during manufacture, the variation, and the assembly variation of the brush holder 17. To do.

At the time of the life of the brush 16, as indicated by a vertical solid line B in FIG. 5, the force with which the brush 16 presses the commutator 15 is suddenly weakened, and the fixing torque of the armature 13 is rapidly reduced. Here, the life of the brush 16 may be when the wear of the brush 16 has progressed and the length of the brush 16 has reached the minimum length that can be used. Further, as the life of the brush 16, the wear of the brush 16 progresses, and the brush 16 may be worn to a length recommended as a value that can maintain the function as the starter 3.
The spring load at which the fixing torque of the armature 13 suddenly decreases due to the wear of the brush 16 is caused by errors in the length of the brush 16, variations, and further the brush holder, as indicated by the vertical broken lines B1 and B2 in FIG. It varies depending on 17 assembly variations.
The brush 16 usually wears faster than the positive side brush, and the negative side brush remains. However, in FIG. 5, the positive side brush and the negative side brush are evenly worn, and at the same time, the worst case is reached. It is a thing.

  For this reason, the minimum fixed torque c (Nm) of the armature 13 is the minimum value of the seal pressing force of the armature bearing 38, the minimum amount of grease applied to the armature bearing 38, and the minimum grease viscosity applied to the armature bearing 38. It is the value when the viscosity is further worn out until the brush 16 reaches the end of its life. As described above, the minimum fixed torque of the armature 13 is the smallest possible value that the armature 13 can take in consideration of the fluctuation factors of the fixed torque such as manufacturing variations of components related to the armature 13 and changes with time of the components. It can be a fixed torque.

  The life of the brush 16 in the first embodiment refers to a point in time when the electrical connection between the brush 16 and the commutator 15 is weakened or stopped due to wear of the brush 16 and the starter 3 cannot start the engine 1. Can be. Instead of such a fixed life time setting, the control device 10 may count the number of times the starter 3 has been operated since the brush 16 is new and the count reaches a predetermined value. The predetermined value may be, for example, the sum of a predetermined brush replacement count and a safety margin count. Furthermore, the control device 10 may count the travel distance from when the brush 16 is new and the count reaches a predetermined value. The predetermined value may be, for example, the sum of a predetermined brush replacement distance and a safety margin distance.

(Effect of Example 1)
Always-starter shown in this embodiment 1, as described above, but also than the maximum idle torque a (Nm) of the one-way clutch 6, and set so that the minimum fixed torque c of A Macha 13 (Nm) increases It is. That is, each component is configured so that a <c .
In this way, by providing the minimum fixed torque c (Nm) of the armature 13 larger than the maximum idling torque a (Nm) of the one-way clutch 6, the brush 16 reaches the end of its service life, and the output shaft 4 of the starter 3 is reached. Even if the fixed torque c of the one-way clutch 6 is minimized and the idling torque a of the one-way clutch 6 is maximized, there is no problem that the armature 13 is rotated by the idling torque of the one-way clutch 6.
That is, when the armature 13 rotates with the idling torque of the one-way clutch 6, the rotation transmitted to the output shaft 4 is accelerated by the planetary gear reduction device 12, the armature 13 rotates at a high speed, and the armature 13 Although there is a possibility that the armature 13 may be broken, the breakage of the armature 13 can be reliably prevented by the first embodiment, so that the reliability of the always-connected starter can be improved.

In the following, the same reference numerals as those in the first embodiment denote the same functional objects .
The second embodiment shown in FIG. 6, the crank shaft 2 and the one-way clutch 6 is intended to be the power transmission by the power transmission means 5 composed of a mesh of a plurality of gears 71,81,91. When using the power transmission means 5 by meshing a plurality of gears 71, 81, 91, a load in a direction orthogonal to the axial direction is not applied to the one-way clutch 6 and the output shaft 4.
For this reason, in this Example 2 , it is not necessary to consider the influence of the power transmission means 5 .

(Modification 1)
In the above embodiment, an example in which the planetary gear speed reduction device 12 is interposed between the output shaft 4 and the armature shaft 21 is shown, but a speed reduction device having another configuration is interposed between the output shaft 4 and the armature shaft 21. May be. Further, the present invention may be applied to an always-connected starter in the case where no speed reduction device is interposed between the output shaft 4 and the armature shaft 21 by increasing the speed reduction ratio of the power transmission means 5.

  In the above embodiment, an example in which the one-way clutch 6 is interposed between the power transmission means 5 and the output shaft 4 of the starter 3 has been described. However, the one-way clutch 6 is connected to the crankshaft 2 of the engine 1 and the power transmission means 5. The present invention may be applied to a constantly connected starter interposed therebetween.

It is a schematic block diagram of the always-connected starter of Example 1. It is a side view of the starter which shows a partial cross section structure. It is principal part sectional drawing of a one way clutch. It is operation | movement explanatory drawing of a one way clutch. It is a graph which shows the relationship between the fixed torque of an armature, and the load of a brush spring. It is a schematic block diagram of the always-connected starter of Example 2 .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Crankshaft 3 Starter 4 Output shaft 5 Power transmission means 6 One-way clutch 7 Large diameter pulley 8 Small diameter pulley 9 Belt 11 Electric motor 13 Armature 16 Brush 31 Inner (drive wheel)
32 Outer (driven wheel)

Claims (5)

In the always-connected starter in which the crankshaft of the engine and the output shaft of the starter are always connected via a one-way clutch that transmits rotational power from the output shaft only to the crankshaft,
The always-connected starter characterized in that the minimum fixed torque of the armature of the electric motor of the starter is larger than the maximum idling torque of the one-way clutch. The always-on starter according to claim 1 ,
The minimum fixed torque of the armature is a fixed torque of the armature during the life of the brush of the electric motor. In the always-on starter according to claim 1 or 2 ,
The one-way clutch drive wheel is mounted on the output shaft;
The crankshaft and the driven wheel of the one-way clutch are configured to transmit power through power transmission means. In the always-on starter according to claim 3 ,
The power transmission means includes a belt and a pulley, and a constant connection starter. In the always-on starter according to claim 3 ,
The power transmission means includes a plurality of gears, and is a constantly connected starter.

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