JP2007278158A - Engine start device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent a one-way clutch from being damaged by excessive shock torque from the engine side associated with engine start. <P>SOLUTION: A web part 3b of a crank shaft 3 is provided with a crank flange 31 and has a ring gear 16 provided helical teeth 16a fitted thereon. An output gear 25 with an one way clutch 30 of an engine start device 20 always meshes with the ring gear 16. Outer diameter dimension of the crank flange 31 is set to a diameter same as or little bit exceeding a pitch circle of teeth of the ring gear 16. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an engine starter, and more specifically, is suitably applied to a vehicle including an idling stop mechanism.

  Patent Document 1 discloses a constantly meshing engine starter in which a ring gear provided on a web portion of a crankshaft is connected to a starter motor via an intermediate gear and a one-way clutch is interposed in the intermediate gear. Has been. Moreover, in the engine starting device of this patent document 1, in order to suppress generation | occurrence | production of noise, the helical gear is employ | adopted as a ring gear.

Since the engine can be smoothly started by adopting the constant meshing type as the engine starting device in this way, it is suitable for a vehicle equipped with an idling stop mechanism that executes engine stop and engine start subsequent thereto.
JP 2004-239241 A

  However, in the always-engaged engine starter, since the sudden shock torque from the engine side accompanying the engine start is input to the one-way clutch, the one-way clutch may be damaged by this shock torque. .

  An object of the present invention is to provide an engine starter capable of preventing a one-way clutch from being damaged by an excessive shock torque from the engine side when the engine is started.

According to the first aspect of the present invention, the above technical problem is
A starting motor that operates when the engine is started;
A plurality of gears attached to a common gear shaft, and an intermediate gear unit that transmits the driving force of the starting motor to the engine;
In the engine starting device, the intermediate gear unit includes an output gear that is always meshed with a crank gear provided in a web portion of the crankshaft, and a one-way clutch disposed between the output gear and the common gear shaft.
The crank gear is composed of a ring gear fitted with helical teeth and fitted on a web portion of the crankshaft,
The degree of fitting of the ring gear to the web portion is set so that the sliding torque at which the ring gear starts to slide around the web portion is lower than the allowable torque of the one-way clutch,
The web portion to which the ring gear is fitted is provided with a crank flange that comes into contact with one side surface of the ring gear, and the outer diameter of the crank flange is the same as or equal to the pitch circle of the teeth of the ring gear. This is achieved by providing an engine starter characterized by having a larger diameter.

  According to the first aspect of the invention, the ring gear is fitted to the web portion of the crankshaft, and the sliding torque at which the ring gear starts to slide around the web portion is lower than the allowable torque of the one-way clutch. Therefore, during the engine start by operating the engine start motor, for example, the clutch provided in the vehicle drive system is suddenly engaged and the rotation of the crankshaft suddenly stops. When the shock torque is applied to the ring gear, the ring gear can be mitigated by sliding around the web portion, so that the one-way clutch incorporated in the engine starting device is protected. Can do.

  However, in this way, when ring gear sliding (sliding) as a crank gear is used to protect the one-way clutch, a lateral force is generated when it has helical teeth for noise reduction. As a result, the ring gear tilts, and there is a risk that a large gear noise may be generated due to inconsistent engagement between the ring gear and the output gear.

  On the other hand, according to the invention of the first aspect, the outer diameter of the crank flange that abuts one side surface of the ring gear has the same diameter as or larger than the pitch circle of the teeth of the ring gear. Therefore, since the crank flange can counter the moment acting in the vicinity of the helical gear teeth of the ring gear, it is possible to suppress the phenomenon that the ring gear tilts and prevent the generation of large gear noise.

According to the second aspect of the present invention, the aforementioned technical problem is
A starting motor that operates when the engine is started;
A plurality of gears attached to a common gear shaft, and an intermediate gear unit that transmits the driving force of the starting motor to the engine;
In the engine starting device, the intermediate gear unit includes an output gear that is always meshed with a crank gear provided in a web portion of the crankshaft, and a one-way clutch disposed between the output gear and the common gear shaft.
The crank gear is composed of a ring gear fitted with helical teeth and fitted on a web portion of the crankshaft,
The degree of fitting of the ring gear to the web portion is set so that the sliding torque at which the ring gear starts to slide around the web portion is lower than the allowable torque of the one-way clutch,
A crank flange that comes into contact with one side surface of the ring gear is provided on the web portion to which the ring gear is fitted,
The ring gear is achieved by providing an engine starter characterized in that an inner peripheral surface thereof is formed in a stepped shape and is fitted to the web portion and the crank flange.

  According to the second aspect of the invention, like the first aspect of the invention, the ring gear sliding (sliding) as a crank gear is used for protecting the one-way clutch. With respect to the possibility of generating large gear noise due to tilting, the crank gear against the moment acting near the helical teeth of the ring gear by the stepped inner surface of the ring gear fitted to the web portion of the crankshaft and the crank flange Since it can be countered by the flange, the phenomenon that the ring gear tilts can be suppressed to prevent the generation of large gear noise.

  In a preferred embodiment of the invention according to the second aspect, the slip torque is defined by fitting the ring gear having a stepped inner peripheral surface with the web portion. In other words, the fitting between the ring gear and the web portion is designed so as to regulate the sliding around the web portion of the ring gear when an excessive torque acts on the ring gear. In other words, the engagement with the crank flange may be such that the inner surface of the ring gear and the crank flange abut. According to this, even if a stepped inner ring gear is employed, the above-described slip torque can be easily managed.

According to the third aspect of the present invention, the aforementioned technical problem is
A starting motor that operates when the engine is started;
A plurality of gears attached to a common gear shaft, and an intermediate gear unit that transmits the driving force of the starting motor to the engine;
In the engine starting device, the intermediate gear unit includes an output gear that is always meshed with a crank gear provided in a web portion of the crankshaft, and a one-way clutch disposed between the output gear and the common gear shaft.
The crank gear is composed of a ring gear fitted with helical teeth and fitted on a web portion of the crankshaft,
The degree of fitting of the ring gear to the web portion is set so that the sliding torque at which the ring gear starts to slide around the web portion is lower than the allowable torque of the one-way clutch,
A crank flange that comes into contact with one side surface of the ring gear is provided on the web portion to which the ring gear is fitted,
Provided is an engine starter characterized in that a stopper plate is attached to a surface of the web portion opposite to the crank flange, and the ring gear is sandwiched between the stopper plate and the crank flange. Is achieved.

  According to the third aspect of the invention, similarly to the first aspect of the invention, the ring gear sliding (sliding) as a crank gear is used to protect the one-way clutch. With regard to the possibility of generation of large gear noise due to tilting, the phenomenon of tilting the ring gear can be suppressed by sandwiching the ring gear between the stopper plate and the crank flange, and generation of large gear noise can be prevented.

  Of course, even if the ring gear is sandwiched between the stopper plate and the crank flange, when the predetermined torque (sliding torque described above) is applied to the ring gear, the ring gear will respond accordingly. The stopper plate and the crank flange should be designed so as not to be excessively pressed against the side surface of the ring gear so as not to hinder sliding around.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 shows an engine to which the present invention is applied, and FIG. 2 shows an engine starter included in the engine of FIG.

  Referring to FIG. 1, engine 1 has a cylinder block 2, and this cylinder block 2 is of a deep skirt type that extends downward from the axis of crankshaft 3. A cylinder head 4 is fastened on the cylinder block 2, while an oil pan 5 is fastened on the bottom of the cylinder block 2. The oil pan 5 is made of a cast product having relatively high rigidity and excellent sound insulation. The engine 1 is provided with an idle stop mechanism that stops the operation of the engine 1 on the assumption that an accelerator pedal (not shown) is released and a brake pedal (not shown) is depressed.

  The engine 1 is an in-line four-cylinder engine in which four cylinders 2a are arranged in series. For each cylinder 2a, a combustion chamber 7 is defined by a piston 6 and a cylinder head 4, and facing the combustion chamber 7, An intake port 8 and an exhaust port 9 are opened. The intake port 8 is provided with an intake valve 11 that is driven to open and close by a first cam shaft 10, and the exhaust port 9 is provided with an exhaust valve 13 that is driven to open and close by a second cam shaft 12. It is installed.

  The first and second camshafts 10 and 12 are connected to the crankshaft 3 via a timing belt (not shown), and intake air is generated by the rotation of the first and second camshafts 10 and 11 synchronized with the rotation of the crankshaft 3. The valve 11 and the exhaust valve 13 are opened and closed at a predetermined timing. The engine 1 is a gasoline engine provided with a spark plug (not shown). The reciprocating vertical movement of each piston 6 is transmitted to the crankshaft 3 via the connecting rod 15, and the output is taken out by the rotational movement of the crankshaft 3.

  Referring to FIG. 2, the crankshaft 3 has a web portion or counterweight 3 b that is located across a crankshaft 3 a to which each connecting rod 15 is rotatably connected. Among these, one web portion 3 b includes The ring gear 16 is formed in a circular contour, and the web portion 3b is fitted using a method such as press fitting or shrink fitting. The ring gear 16 constitutes a starting crank gear that forms part of the engine starting device 20. This starting crank gear, that is, the ring gear 16 is provided with helical teeth 16a.

  The engine starter 20 includes a starter motor 21 constituted by a DC motor, and an intermediate gear unit 22 that transmits the output of the starter motor 21 to the ring gear 16. The starter motor 21 is disposed outside the oil pan 5, and in order to receive the starter motor 21 in the lower part of the engine 1, a part of the oil pan 5 is recessed inwardly, and the oil pan 5 A starting motor storage portion 5a is formed in which a part of the bottom wall of the motor is recessed upward (FIG. 1).

  The intermediate gear unit 22 is disposed inside the oil pan 5. The intermediate gear unit 22 includes a gear shaft 23 disposed in parallel with the crankshaft 3, and the gear shaft 23 includes an input gear 24 at one end and an output gear 25 at the other end.

  The input gear 24 is spline-coupled to the gear shaft 23, thereby rotating integrally with the gear shaft 23. A rotational force from the starting motor 21 is input to the input gear 24 via the pinion gear 26 of the starting motor 21. On the other hand, the output gear 25 meshes with the ring gear (crank gear) 16 described above, and is attached to the gear shaft 23 via a one-way clutch 30.

  The one-way clutch 30 allows the power on the gear shaft 23 side to be transmitted to the ring gear (crank gear) 16 while blocking the power transmission from the ring gear 16 side to the gear shaft 23. Thus, the intermediate gear unit 22 can start the engine 1 by transmitting the rotational driving force of the starter motor 21 to the crankshaft 3, and after the engine 1 is started, the engine 1 (crankshaft 3) side Can be prevented from being input to the intermediate gear unit 22.

  Regarding the attachment of the ring gear (crank gear) 16, as described above, the ring gear 16 is a helical gear and is fitted to the web portion 3 b of the crankshaft 3. Therefore, when an excessive force is applied to the ring gear 16, there is a possibility that the ring gear (helical gear) 16 slides and is displaced relative to the web portion 3b. In the embodiment, when an excessive torque is applied between the ring gear 16 and the output gear 25 meshing with the ring gear 16, the degree of fitting of the ring gear 16 is such that the ring gear 16 slides between the web portions 3 b. Thus, the intermediate gear unit 22 including the one-way clutch 30 is protected. A typical example of the excessive torque is a torque greater than the allowable torque of the one-way clutch 30, and if this is used as a reference, the slip torque at which the ring gear 16 starts to slide relative to the web portion 3b is the ring torque. The degree of fitting of the ring gear 16 with respect to the web portion 3b is set so that the degree of fitting of the gear 16 is lower than the allowable torque of the one-way clutch 30.

  FIG. 3 is a diagram for explaining a problem in the middle of starting the engine with the starter motor 21. In the figure, reference numeral 31 denotes a crank flange formed on the web portion 3 b of the crankshaft 3, and the ring gear 16 is positioned by press-fitting the ring gear 16 until it abuts against the crank flange 31. Note that FIG. 3 is substantially the same in terms of function, although the arrangement of the output gear 25 and the one-way clutch 30 with respect to the gear shaft 23 is different in relation to FIG.

  Referring to FIG. 3, while the engine starter 20 is operated and the engine is started, that is, in a state where the gear shaft 23 of the intermediate gear unit 22 is rotationally driven by the starter motor 21, for example, the vehicle When the rotation of the crankshaft 3 suddenly stops due to sudden engagement of a clutch (not shown) provided in the drive system, the shock torque is applied to the ring gear 16 and the output gear 25 meshed therewith, If the torque is excessive, the ring gear 16 slides around the web portion 3b. Since both the output gear 25 and the ring gear 16 are helical gears, the output gear 25 and the ring gear 16 have thrusts F1 and F2 in directions parallel to the crankshaft 3 and the gear shaft 23, respectively. Force acts. Needless to say, it is preferable to set the direction in which the ring gear 16 is inserted so that the thrust force F2 is received by the crank flange 31 when this is taken into consideration.

  Assuming the above, a moment M1 is generated in the direction of the arrow in the vicinity of the helical tooth 16a of the ring gear 16, and this moment M1 is diametrically opposite to the portion meshing with the output gear 25. There is a possibility that a force F3 acts in the direction away from the crank flange 31 on the opposite side in the diametrical direction, and the part moves in a direction away from the crank flange 31 due to the force F3. Then, when the ring gear 16 is inclined due to this, there is a possibility that a large gear noise is generated due to the inconsistent engagement between the ring gear 16 and the output gear 25.

  FIG. 4 shows an example of how to deal with the above-mentioned concerns. In this first example, a ring-shaped stopper plate 35 is prepared so that the above-described sliding around the web portion 3b of the ring gear 16 is not obstructed, and the ring gear is constituted by the crank flange 31 and the stopper plate 35 described above. The structure which clamps 16 is employ | adopted. The stopper plate 35 is fixed to the side surface of the web portion 3b opposite to the crank flange 31 by using, for example, a bolt 36 after the ring gear 16 is fitted into the web portion 3b.

  According to Example 1 illustrated in FIG. 4, since the force of F3 described above is received by the stopper plate 35 attached to the ring gear 16, the phenomenon that the ring gear 16 tilts can be suppressed. An increase in gear noise can be prevented.

  FIG. 5 shows a second example of dealing with the concerns described above. This second example can be adopted instead of the first example described above or together with the first example. Referring to FIG. 5, the ring gear 16 is expanded to a position where its width interferes with the crank flange 31. The inner peripheral surface of the ring gear 16 is formed in a stepped shape. That is, the ring gear 16 has an extension portion 16b that rides on the crank flange 31, and the extension portion 16b and the crank flange 31 are fitted to each other with a fitting degree smaller than the degree of fitting between the main body portion 16c and the web portion 3b. It is preferable to set the dimensions so as to achieve a fitting degree (for example, a press-fitting degree that is about half of the press-fitting degree of the main body portion 16c and the web portion 3b or an extent that the extension portion 16b contacts the outer peripheral surface of the crank flange 31).

  According to this, the ring gear 16 is substantially integrated with the web portion 3b by fitting with the web portion 3b, and the above-described sliding around the web 3b of the ring gear 16 is not hindered. Due to the engagement between the extended portion 16c of the ring gear 16 and the crank flange 31, that is, the stepped shape of the inner surface of the ring gear 16 fitted to the web portion 3 and the crank flange 31, the moment M1 described above with reference to FIG. Since it can counter, the phenomenon in which the ring gear 16 tilts can be suppressed, and this can prevent an increase in gear noise accompanying the tilting of the ring gear 16.

  FIG. 6 shows a third example of dealing with the concerns described above. This third example can be employed instead of the first example described above or together with the first example. Referring to FIG. 6, the outer diameter of the crank flange 31 is enlarged so as to be the same as or preferably slightly beyond the pitch circle of the teeth of the ring gear 16. Needless to say, the crank flange 31 having an enlarged outer diameter does not interfere with the output gear 25 and the crank flange 31 even when the dimension crossing and geometrical tolerance of the output gear 25 of the intermediate gear unit 22 are taken into consideration. It is preferable to set the outer diameter dimension.

  According to the third example, since the vicinity of the helical teeth 16a of the ring gear 16 is supported by the crank flange 31, this prevents the above-described sliding around the web portion 3b of the ring gear 16 from being hindered. Since the moment M1 described above with reference to FIG. 3 can be countered, the phenomenon that the ring gear 16 tilts can be suppressed, and an increase in gear noise accompanying the tilting of the ring gear 16 can be prevented.

It is a figure which cuts off a part of engine which applied this invention, and shows an internal structure. It is the figure which extracted the part relevant to the engine starting apparatus of the engine of FIG. It is a figure for demonstrating the problem which generate | occur | produces in relation to the helical gear with the helical tooth employ | adopted as the engine of FIG. 1, and the output gear of the engine starting apparatus which always meshes with this. It is a figure for demonstrating the 1st improvement measure which prevents that a crank gear inclines. It is a figure for demonstrating the 2nd improvement measure which prevents that a crank gear inclines. It is a figure for demonstrating the 3rd improvement measure which prevents that a crank gear inclines.

Explanation of symbols

1 Engine 3 Crankshaft 3b Crankshaft Web 6 Piston 16 Ring Gear (Crank Gear)
16a Helical tooth 16b Extension part 20 Engine starter 21 Starter motor 22 Intermediate gear unit 23 Gear shaft (common gear shaft)
24 input gear 25 output gear 26 pinion gear (starting motor)
30 One-way clutch 31 Crank flange of crankshaft web 35 Stopper plate

Claims (4)

A starting motor that operates when the engine is started;
A plurality of gears attached to a common gear shaft, and an intermediate gear unit that transmits the driving force of the starting motor to the engine;
In the engine starting device, the intermediate gear unit includes an output gear that is always meshed with a crank gear provided in a web portion of the crankshaft, and a one-way clutch disposed between the output gear and the common gear shaft.
The crank gear is composed of a ring gear fitted with helical teeth and fitted on a web portion of the crankshaft,
The degree of fitting of the ring gear to the web portion is set so that the sliding torque at which the ring gear starts to slide around the web portion is lower than the allowable torque of the one-way clutch,
The web portion to which the ring gear is fitted is provided with a crank flange that comes into contact with one side surface of the ring gear, and the outer diameter of the crank flange is the same as or equal to the pitch circle of the teeth of the ring gear. An engine starter characterized by having a larger diameter. A starting motor that operates when the engine is started;
A plurality of gears attached to a common gear shaft, and an intermediate gear unit that transmits the driving force of the starting motor to the engine;
In the engine starting device, the intermediate gear unit includes an output gear that is always meshed with a crank gear provided in a web portion of the crankshaft, and a one-way clutch disposed between the output gear and the common gear shaft.
The crank gear is composed of a ring gear fitted with helical teeth and fitted to the web portion of the crankshaft;
The degree of fitting of the ring gear to the web portion is set so that the sliding torque at which the ring gear starts to slide around the web portion is lower than the allowable torque of the one-way clutch,
A crank flange that comes into contact with one side surface of the ring gear is provided on the web portion to which the ring gear is fitted,
An engine starter characterized in that the ring gear has an inner peripheral surface formed in a stepped shape and is fitted to the web portion and the crank flange.   The engine starting device according to claim 2, wherein the slip torque is defined by fitting the ring gear having the stepped inner peripheral surface with the web portion. A starting motor that operates when the engine is started;
A plurality of gears attached to a common gear shaft, and an intermediate gear unit that transmits the driving force of the starting motor to the engine;
In the engine starting device, the intermediate gear unit includes an output gear that is always meshed with a crank gear provided in a web portion of the crankshaft, and a one-way clutch disposed between the output gear and the common gear shaft.
The crank gear is composed of a ring gear fitted with helical teeth and fitted on a web portion of the crankshaft,
The degree of fitting of the ring gear to the web portion is set so that the sliding torque at which the ring gear starts to slide around the web portion is lower than the allowable torque of the one-way clutch,
A crank flange that comes into contact with one side surface of the ring gear is provided on the web portion to which the ring gear is fitted,
An engine starter characterized in that a stopper plate is attached to a surface of the web portion opposite to the crank flange, and the ring gear is sandwiched between the stopper plate and the crank flange.

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