JP4479670B2 - Starter - Google Patents

Description

  The present invention relates to a constant mesh starter in which a pinion gear is always meshed with a ring gear on the engine side.

Conventionally, a general electromagnetic push-in starter that pushes out the pinion gear and meshes with the ring gear on the engine side is not engaged with the ring gear except at the time of starting. The generated driving force is transmitted from the pinion gear to the ring gear to drive the engine, and after the engine is started, the pinion gear is detached from the ring gear by returning the ignition switch from the START position to the ON position.
In this electromagnetic push-in type starter, even if the engine is stopped before the engine stops (when the engine is coasting), the ring gear on the engine side rotates at high speed, and the pinion gear meshes with the ring gear. It is difficult to restart the engine before it stops.

  On the other hand, there is known an always-meshing starter in which an engine-side ring gear and a starter-side pinion gear are always meshed directly or via an intermediate gear or the like (see Patent Document 1). In this constant mesh starter, the pinion gear does not disengage from the ring gear after the engine is started, and is always meshed. Therefore, restart before the engine stops is possible. Further, in the electromagnetic push-in type starter, a meshing sound is generated when the pinion gear meshes with the ring gear. However, since the meshing sound is not generated in the constant meshing type starter, it is excellent in terms of quietness.

By the way, in starting the engine, when the engine is completely exploded and the engine speed exceeds the starter speed, the pinion gear is rotated to the ring gear. At this time, the armature of the starter motor has a rotational speed (generally, about a ring gear: about 8 to 15 with respect to a pinion gear: 1 to a ring gear: about 15 to 15). The rotation speed is multiplied by the reduction ratio), which causes the armature to be damaged by centrifugal force.
In order to prevent this, a one-way clutch is provided in the starter or on the ring gear side. The one-way clutch has a function of idling when the engine speed exceeds the starter speed and not transmitting the engine speed to the armature.

  However, the one-way clutch that rotates idly when the engine speed exceeds the starter speed is always engaged because the engine rotates in the reverse direction due to rocking when the engine is stopped. In the meshing starter, the rotational force generated in the reverse rotation direction is transmitted from the engine side to the starter side. As a result, the armature is rotated at the number of revolutions multiplied by the gear ratio (reduction ratio) between the ring gear and the pinion gear (in a starter having an internal reduction gear, the number of revolutions multiplied by the internal reduction ratio). There is a concern that the service life may be reduced and the armature may be damaged by centrifugal force.

Therefore, the present applicant has proposed a starter provided with a reverse rotation prevention clutch that prevents the armature shaft from rotating in the direction opposite to that when the engine is driven (see Patent Document 2).
The reverse rotation prevention clutch includes a clutch inner provided on the armature shaft, a clutch-shaped cam chamber formed between the clutch inner and the clutch inner. It is composed of a clutch member (for example, a roller) disposed in the chamber, and when the engine starts, the clutch member idles to allow the armature shaft to rotate, and the reverse rotation of the engine is transmitted to the armature shaft. The clutch member moves in the narrow direction of the cam chamber and engages with the clutch inner and the clutch outer, thereby preventing reverse rotation of the armature shaft.
JP 2004-225544 A Japanese Patent Application No. 2005-38081

  However, in the clutch for preventing reverse rotation described in Patent Document 2, the clutch inner is formed integrally with the armature shaft. For this reason, it is necessary to use the same material for the armature shaft and the clutch inner. For example, if the material of the clutch inner portion is changed to a high-strength material in order to improve the allowable torque of the clutch, the electric The material of the shaft is also changed. As a result, for example, when the armature shaft is formed by forging, if the entire armature shaft is changed to a high-strength material, the forging process becomes difficult, and the formability of the armature shaft deteriorates.

  In addition, when the armature shaft is formed by forging, the outer diameter of the clutch inner is restricted for reasons of forming. That is, there is a problem that the outer diameter of the clutch inner cannot be increased because the outer diameter of the clutch inner that can be processed by forging is limited by the outer diameter of the armature shaft. If the armature shaft is machined by cutting, if the outer diameter of the clutch inner is made larger than the outer diameter of the armature shaft, the yield deteriorates and the cost increases.

  Furthermore, in order to improve the performance against wear, deformation, breakage, etc., the armature shaft performs heat treatment such as induction hardening on the bearing portion, gear portion, clutch inner portion, etc., but the clutch inner is integrated with the armature shaft. When molded, the following problems occur. That is, after assembling an armature core, armature coil, commutator, etc. to the armature shaft and assembling as an armature assembly, in order to improve the centrifugal strength of the armature, powder processing is performed on the outer peripheral portion of the armature coil In this case, the clutch inner part is hardened by heat when the powder treatment is performed, and the strength is lowered. In particular, if the clutch inner portion is provided near the powder processing portion, it is likely to be affected by heat during the powder processing, and there is a concern that the strength of the clutch inner portion may be reduced.

In addition, the clutch outer of the reverse rotation prevention clutch is integrally formed with a portion that forms a cam chamber and a portion that is non-rotatably fixed to a housing or the like, and the cam chamber is shaped like a wedge (wedge shape). For this reason, when the clutch outer is manufactured by forging, there is a problem that it is difficult to form the clutch outer.
The present invention has been made based on the above circumstances, and an object thereof is to provide a clutch inner integrally provided with an armature shaft in a starter including a reverse rotation prevention clutch capable of preventing reverse rotation of the armature shaft. The problem is to solve the problem.

(Invention of Claim 1 )
The starter of the present invention includes a reverse rotation prevention clutch that prevents the armature shaft of the motor from rotating in the direction opposite to that when the engine is driven. The reverse rotation preventing clutch is disposed concentrically with a clutch inner provided on the armature shaft, and is fixed to the housing or a yoke forming a magnetic circuit of the motor so as not to rotate. A clutch outer that forms a wedge-shaped cam chamber with the inner, and a cam chamber that moves in the direction of narrowing of the cam chamber when rotation in the direction opposite to that when the engine is driven is transmitted to the armature shaft. A clutch member that prevents rotation of the clutch inner. The clutch inner is provided separately from the armature shaft and is fixed to the outer periphery of the armature shaft by press-fitting. The armature shaft is press-fitted by the clutch inner. A sun gear that transmits the rotation of the armature shaft to the planetary gear of the speed reducer is formed on the side opposite to the axial direction of the portion (referred to as the inner press-fit portion) to be driven. Wherein the direction of the outside diameter of the part is provided larger
According to said structure, since a clutch inner is provided separately from an armature shaft, the material of a clutch inner and an armature shaft can be set separately. Thereby, for example, in order to improve the wear resistance and strength of the clutch inner, only the material of the clutch inner can be changed to a high-strength material, and the material of the armature shaft can be easily forged, for example. The material can be selected. Further, different heat treatments can be applied to the armature shaft and the clutch inner. For example, induction-hardening can be performed on the bearing portion and gear portion of the armature shaft, and carburizing and quenching can be performed on the clutch inner.
Further, since the outer diameter of the clutch inner does not affect the formability of the armature shaft, for example, the armature shaft can be easily processed by forging, which is advantageous in terms of cost.
Further, when performing powder processing to improve the centrifugal strength of the armature, the powder processing is performed before the clutch inner is fixed to the armature shaft, and after the powder processing step is completed, the clutch inner is performed. Can be fixed to the armature shaft. As a result, even when the clutch inner is provided near the powder processing portion, the clutch inner is not affected by the heat during powder processing, so there is no concern that the strength of the clutch inner is reduced by the powder processing. .
In addition, the clutch inner can be easily fixed to the armature shaft by press-fitting the outer periphery of the armature shaft, and the coaxiality between the armature shaft and the clutch inner can be easily obtained. Contribute.
Furthermore, by providing the outer diameter of the inner press-fit portion larger than the outer diameter of the sun gear, the clutch inner can be press-fitted into the inner press-fit portion from the sun gear side of the armature shaft, so that the armature core, armature coil, commutator is applied to the armature shaft. After assembling the armature assembly, the clutch inner can be fixed to the inner press-fit portion of the armature shaft by press-fitting.

(Invention of Claim 2 )
The starter of the present invention includes a reverse rotation prevention clutch that prevents the armature shaft of the motor from rotating in the direction opposite to that when the engine is driven. The reverse rotation preventing clutch is disposed concentrically with a clutch inner provided on the armature shaft, and is fixed to the housing or a yoke forming a magnetic circuit of the motor so as not to rotate. A clutch outer that forms a wedge-shaped cam chamber with the inner, and a cam chamber that moves in the direction of narrowing of the cam chamber when rotation in the direction opposite to that when the engine is driven is transmitted to the armature shaft. A clutch member that prevents rotation of the clutch inner . The clutch inner is provided separately from the armature shaft, and is fixed to the outer periphery of the armature shaft by press-fitting and is also fixed to the armature shaft. The armature iron core is in contact with the axial end surface.
According to said structure, since a clutch inner is provided separately from an armature shaft, the material of a clutch inner and an armature shaft can be set separately. Thereby, for example, in order to improve the wear resistance and strength of the clutch inner, only the material of the clutch inner can be changed to a high-strength material, and the material of the armature shaft can be easily forged, for example. The material can be selected. Further, different heat treatments can be applied to the armature shaft and the clutch inner. For example, induction-hardening can be performed on the bearing portion and gear portion of the armature shaft, and carburizing and quenching can be performed on the clutch inner.
Further, since the outer diameter of the clutch inner does not affect the formability of the armature shaft, for example, the armature shaft can be easily processed by forging, which is advantageous in terms of cost.
Further, when performing powder processing to improve the centrifugal strength of the armature, the powder processing is performed before the clutch inner is fixed to the armature shaft, and after the powder processing step is completed, the clutch inner is performed. Can be fixed to the armature shaft. As a result, even when the clutch inner is provided near the powder processing portion, the clutch inner is not affected by the heat during powder processing, so there is no concern that the strength of the clutch inner is reduced by the powder processing. .
In addition, the clutch inner can be easily fixed to the armature shaft by press-fitting the outer periphery of the armature shaft, and the coaxiality between the armature shaft and the clutch inner can be easily obtained. Contribute.
Furthermore, by making the clutch inner contact with the axial end surface of the armature core, the press-fitting position of the clutch inner with respect to the armature shaft is regulated without using a jig or the like when the clutch inner is press-fitted into the armature shaft. it can.
(Invention of Claim 3)
The starter according to claim 1 or 2, wherein serrations are provided on an outer periphery of the armature shaft into which the clutch inner is press-fitted or an inner periphery of the clutch inner.
In this case, since the press-fit load can be reduced, deformation of the clutch inner can be suppressed.

(Invention of Claim 4 )
In starter according to claim 1 or 2, the surface hardness of the clutch inner is characterized by higher than the surface hardness of the armature shaft clutch inner is pressed.
By increasing the surface hardness of the clutch inner, the permissible surface pressure of the clutch inner can also be improved, so that the diameter of the clutch inner can be reduced compared to the case where the surface hardness of the clutch inner is the same as the surface hardness of the armature shaft. As a result, it is possible to reduce the size of the reverse rotation prevention clutch.

(Invention of Claim 5 )
In starter according to claim 1 or 2, the clutch outer is separate from the outer portion to form a cam chamber, the housing, or, and a fixing portion which is non-rotatably fixed to the yoke for forming a magnetic circuit of the motor It is provided in the body, and the outer part is fixed to the fixing part.
In this case, since the outer part and the fixed part can be manufactured separately, the formability is improved as compared with the case where both are integrally formed.

(Invention of Claim 6 )
The starter described in claim 5 is characterized in that the fixing portion is provided in a ring shape having a round hole, and the outer portion is fixed by press-fitting into the round hole of the fixing portion.
In this case, the outer part can be easily integrated by press-fitting the outer part into the round hole of the fixed part.

(Invention of Claim 7 )
7. The starter according to claim 6 , wherein the clutch inner is fixed to the outer periphery of the armature shaft by press-fitting, and the slip torque of the press-fitted part in which the outer part is press-fitted into the fixed part is larger than the slip torque of the press-fitted part. It is characterized by that.
When an excessive impact exceeding the allowable torque of the reverse rotation prevention clutch is input, the excessive impact can be absorbed by sliding the press-fit portion. At this time, the slip torque of the press-fitted portion (referred to as the press-fit portion on the outer side) between the fixed portion and the outer portion is determined from the slip torque at the press-fit portion (referred to as the press-fit portion on the inner side) between the clutch inner and the armature shaft. By setting a large value, it is possible to always slide the inner press-fit portion when an excessive impact is input. In this case, if only the slip torque of the inner press-fitted portion is managed, an appropriate shock absorbing ability can be exhibited. Moreover, since the clutch inner is a ring-shaped member and has a simple structure, the press-fit portion can be easily managed.

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

FIG. 1 is a half sectional view of a constant mesh starter 1.
As shown in FIG. 1, the starter 1 according to the first embodiment is an electromagnetic switch that opens and closes a motor 2 that generates a rotational force and a main contact (described later) provided in an energization circuit (referred to as a motor circuit) of the motor 2. 3, a speed reducer 4 that decelerates the rotation of the motor 2, an output shaft 5 to which the drive torque of the motor 2 is transmitted via the speed reducer 4, a pinion gear 6 supported by the output shaft 5, and the motor 2 The reverse rotation preventing clutch 7 and the like for preventing the reverse rotation of the motor.
The starter 1 can be used in an engine automatic stop / restart system (called an idle stop, an eco-run system, or the like) that automatically controls engine stop and restart.

The motor 2 is composed of a yoke 8 that forms a magnetic circuit, a permanent magnet 9 (which may be a field coil) that forms a magnetic field on the inner periphery of the yoke 8, an armature 10 that rotates by the action of electromagnetic force, and the like. This is a known DC motor.
The yoke 8 has a cylindrical shape, is sandwiched between the front housing 11 and the end frame 12, and is fixed by fastening a plurality of through bolts (not shown) to the front housing 11 from the rear end of the end frame 12. ing.
The permanent magnets 9 are fixed to the inner peripheral surface of the yoke 8 via the magnet holder 14, and a plurality of permanent magnets 9 are arranged at equal intervals in the circumferential direction of the yoke 8.

The armature 10 includes an armature shaft 14, an armature core 15 that is serrated to the outer periphery of the armature shaft 14, an armature coil 16 wound around the armature core 15, and an armature shaft 14. The commutator 17 is provided on one end side.
The commutator 17 is formed by a plurality of segments arranged in a cylindrical shape around the armature shaft 14 via an insulating material 18, and each segment is electrically and mechanically connected to the armature coil 16. A plurality of carbon brushes 19 are arranged on the outer periphery of the commutator 17.

  The electromagnetic switch 3 includes an electromagnetic coil (not shown) that is energized from a vehicle-mounted battery (not shown) to form an electromagnet, and a plunger (not shown) that is inserted inside the electromagnetic coil. When the electromagnet is formed by energizing the motor, the plunger is attracted to the electromagnet, and the main contact of the motor circuit is closed. When energization of the electromagnetic coil stops and the attraction force of the electromagnet disappears, the plunger is pushed back by the reaction force of a return spring (not shown) to open the main contact.

The main contact is a set of fixed contacts (not shown) connected to the motor circuit via the two external terminals 20 and 21 and a movable movable integrally with the plunger to intermittently connect between the set of fixed contacts. A contact (not shown) and a pair of fixed contacts are connected to each other through the movable contact to close the main contact, and a connection between the set of fixed contacts is interrupted to disconnect the main contact. Open state.
The two external terminals 20 and 21 are a B terminal 20 connected to the in-vehicle battery via a battery cable and an M terminal 21 to which a motor lead wire 22 taken out from the motor 2 is connected. The cover 3a is fixed.

The speed reducer 4 is a well-known planetary gear speed reducer that can decelerate on the same axis as the armature shaft 14. And an internal gear 24 whose rotation is restricted via a torque limiter described below, and a plurality of planetary gears 25 that mesh with both gears 23 and 24.
The torque limiter has a rotating disk 26 whose rotation is restricted by a frictional force. When an excessive torque exceeding the stationary torque of the rotating disk 26 is applied to the internal gear 24, the rotating disk 26 slides against the frictional force ( Rotation), the rotation of the internal gear 24 is allowed and the excessive torque is absorbed.

The output shaft 5 is disposed on the same axis as the armature shaft 14, one end side is connected to the armature shaft 14 via the speed reducer 4, and the other end side is rotatably supported on the front housing 11 via a bearing 27. Has been.
The pinion gear 6 is rotatably fitted to the outer periphery of the output shaft 5 via a bearing 28, is connected to the output shaft 5 via an impact absorbing device described below, and is always meshed with a ring gear 29 on the engine side. ing.

The shock absorber includes a first rotating body 30 that is serrated and fitted to the outer periphery of the output shaft 5, a second rotating body 31 that is serrated and fitted to the outer periphery of a cylindrical portion 6a provided integrally with the pinion gear 6, It is comprised from elastic bodies 32, such as rubber | gum arrange | positioned between the rotary bodies 30 and 31 grade | etc.,. Note that a plurality of elastic bodies 32 are arranged in series between the rotating bodies 30 and 31 via the intermediate member 33 (in FIG. 1, a total of 6 pieces of 3 × 2 per stage).
When starting an engine having a large inertial energy, the impact absorbing device absorbs the impact torque transmitted to the starter 1 by the elastic body 32 being compressed and deformed.

The reverse rotation prevention clutch (hereinafter abbreviated as the clutch 7) includes a clutch inner 34 provided on the armature shaft 14, a concentric arrangement with the clutch inner 34, and a wedge-shaped cam chamber 35 between the clutch inner 34. It comprises a clutch outer 36 forming [see FIG. 3B], a roller 37 disposed in the cam chamber 35, and the like.
The clutch inner 34 has a ring shape provided separately from the armature shaft 14 and is fixed to the outer periphery of the armature shaft 14 by press-fitting. The armature shaft 14 is a portion (referred to as an inner press-fit portion 14a) where the clutch inner 34 is press-fitted between the serration shaft portion into which the armature core 15 is fitted and the gear forming portion where the sun gear 23 is formed. ), And the outer diameter of the inner press-fit portion 14a is slightly larger than the outer diameter of the sun gear 23 (see FIG. 2B).

As shown in FIG. 3, the clutch outer 36 includes an outer portion 36 a that forms a cam chamber 35 on the inner periphery, and a fixed portion 36 b that is fixed to the front housing 11 so as not to rotate.
The clutch outer 36 is assembled by fitting the outer periphery of the fixed portion 36b to the end of the yoke 8 in the axial direction, and the rotation restricting portion 36c provided on the outer periphery of the fixed portion 36b (see FIG. 3B). Is engaged with the inner periphery of the front housing 11 and is restricted in rotation.
As shown in FIG. 3B, the roller 37 is accommodated in the cam chamber 35 together with the spring 38, and is urged by the spring 38 in the narrowing direction of the cam chamber 35.

  The clutch 7 has a function of preventing the armature shaft 14 from rotating in the direction opposite to that when the engine is driven. That is, when the armature shaft 14 rotates when the engine is driven, the roller 37 moves to one side (in the wide direction) of the cam chamber 35 and idles, thereby allowing the clutch inner 34 to rotate. On the other hand, when rotation in the direction opposite to that during engine driving is transmitted from the engine side to the armature shaft 14, the roller 37 moves to the other side (narrow direction) of the cam chamber 35, and the clutch outer 36 and the clutch inner 34 The clutch inner 34 is prevented from rotating by being locked during this time. As a result, the armature shaft 14 is prevented from rotating in the direction opposite to that when the engine is driven.

Next, the operation and effect of the starter 1 will be described.
When the main contact of the motor circuit is closed by the electromagnetic switch 3, the armature coil 16 is energized from the in-vehicle battery, and a rotational force is generated in the armature 10 by the electromagnetic force acting on the armature coil 16. The rotation of the armature 10 is not blocked by the clutch 7 but is transmitted to the output shaft 5 via the speed reducer 4 and further transmitted from the pinion gear 6 to the ring gear 29 to crank the engine. At this time, the impact torque generated in the starter 1 is effectively absorbed by the impact absorbing device. Further, an excessive impact that cannot be absorbed by the impact absorbing device (that is, when the elastic body 32 is fully compressed) is cut by the torque limiter.

When the engine completes explosion and the engine speed exceeds the starter speed, for example, a one-way clutch (not shown) built in the ring gear 29 idles and the ring gear 29 is disconnected from the crankshaft of the engine. The rotation of the engine is not transmitted to the pinion gear 6, and overrun of the armature 10 can be prevented.
Further, when the engine rotates reversely, for example, when the vehicle moves backward due to crankshaft swing or climbing path stall that occurs when the engine is stopped, the reverse rotation is transmitted to the pinion gear 6 that is always meshed with the ring gear 29 to drive the engine. The rotation in the opposite direction to the time is transmitted to the output shaft 5. When the reverse rotation of the output shaft 5 is transmitted to the armature shaft 14 via the speed reducer 4, the roller 37 of the clutch 7 is locked and the rotation of the clutch inner 34, that is, the reverse rotation of the armature shaft 14 is prevented. Therefore, the armature 10 can be prevented from rotating in the direction opposite to that when the engine is driven.

(Effect of Example 1)
In the clutch 7 of this embodiment, the clutch inner 34 is provided separately from the armature shaft 14, and therefore the material of the clutch inner 34 and the armature shaft 14 can be set separately. Thus, for example, in order to improve the wear resistance and strength of the clutch inner 34, only the material of the clutch inner 34 can be changed to a high-strength material. Can be selected easily. Also, different heat treatments can be applied to the armature shaft 14 and the clutch inner 34. For example, the armature shaft 14 can be induction-hardened and the clutch inner 34 can be carburized and quenched.
Further, since the clutch inner 34 and the armature shaft 14 can be manufactured separately, the outer diameter of the clutch inner 34 does not affect the formability of the armature shaft 14. That is, when the armature shaft 14 is manufactured, there is no restriction due to the outer diameter of the clutch inner 34. For example, the armature shaft 14 can be easily processed by forging, which is advantageous in terms of cost. is there.

Furthermore, since the clutch inner 34 is fixed to the outer periphery of the armature shaft 14 by press-fitting, the clutch inner 34 can be easily fixed to the armature shaft 14 and the degree of coaxiality between the armature shaft 14 and the clutch inner 34 is easily obtained. 7 contributes to improving the performance.
Further, by providing the clutch inner 34 separately from the armature shaft 14, the surface hardness of the clutch inner 34 can be set higher than the surface hardness of the inner press-fit portion 14 a of the armature shaft 14. In this case, since the allowable surface pressure of the clutch inner 34 can be improved by increasing the surface hardness of the clutch inner 34, compared with the case where the surface hardness of the clutch inner 34 is the same as the surface hardness of the armature shaft 14, The clutch inner 34 can be reduced in diameter, and as a result, the clutch 7 can be reduced in size.

  Since the outer diameter of the inner press-fit portion 14a is larger than the outer diameter of the sun gear 23, the armature shaft 14 is assembled with the armature core 15, the armature coil 16, the commutator 17, and the like. After being assembled as an armature assembly, the clutch inner 34 can be pressed into the inner press-fit portion 14a from the sun gear 23 side of the armature shaft 14. Thus, after the assembly of the armature assembly, in order to improve the centrifugal strength of the armature 10, when the powder processing (see FIG. 2B) is performed on the outer peripheral portion of the armature coil 16, the clutch inner Powder processing is performed before 34 is fixed to the armature shaft 14, and after the powder processing step is completed, the clutch inner 34 can be pressed into the armature shaft 14 and fixed. As a result, even when the clutch inner 34 is provided in the vicinity of the powder processing portion, the clutch inner 34 is not affected by heat during the powder processing, so that the strength of the clutch inner 34 is reduced by the powder processing. No worries.

4 is a half sectional view of the starter, and FIG. 5 is a half sectional view of the clutch.
The clutch 7 shown in the second embodiment is an example in which the clutch outer 36 is divided into an outer portion 36a and a fixed portion 36b, as shown in FIGS.
The fixing portion 36b is provided in a ring shape having a round hole on the inner periphery, and the outer portion 36a is fixed to the round hole by press-fitting.
When the outer portion 36a and the fixed portion 36b are integrally formed, the cam chamber 35 formed on the inner periphery of the outer portion 36a has an irregular shape (wedge shape), and the outer portion 36a and the fixed portion 36b Therefore, it is difficult to forge the clutch outer 36.

On the other hand, in this embodiment, since the outer portion 36a and the fixed portion 36b can be manufactured separately, for example, the outer portion 36a that is difficult to forge is processed by cutting, and the fixed portion 36b having a simple shape is formed by forging. Processing is also possible, and the moldability of the clutch outer 36 is improved as compared with the case where both are formed integrally.
Further, the sliding torque of the press-fit portion (outer-side press-fit portion) into which the outer portion 36a is press-fitted into the round hole of the fixed portion 36b, and the press-fit portion (inner-side press-fit portion) between the clutch inner 34 and the armature shaft 14 When comparing with the slip torque, the slip torque of the outer press-fit portion is set larger than the slip torque of the inner press-fit portion. As a result, when an excessive impact exceeding the allowable torque of the clutch 7 is input, the inner side press-fit portion can be slid without fail. Therefore, if only the slip torque of the inner-side press-fit portion is managed, appropriate shock absorption can be achieved. Can demonstrate ability. Moreover, since the clutch inner 34 is a ring-shaped member and has a simple structure, the press-fit portion can be easily managed.

(Modification)
In the first and second embodiments, serrations may be provided on the outer periphery of the armature shaft 14 into which the clutch inner 34 is press-fitted or on the inner periphery of the clutch inner 34. In this case, since the press-fitting load can be reduced, deformation of the clutch inner 34 accompanying press-fitting can be suppressed.
In addition, the clutch inner 34 may abut the end face on the side opposite to the speed reducer to the end face in the axial direction of the armature core 15. In this case, when the clutch inner 34 is press-fitted into the armature shaft 14, the press-fitting position of the clutch inner 34 with respect to the armature shaft 14 can be regulated without using a jig or the like.

(Example 1) which is a half sectional view of a constant meshing starter. (A) The axial front view of an armature, (b) The half sectional view of an armature. (A) Half sectional view of a clutch, (b) A plan view of a clutch (Example 1). (Example 2) which is a half sectional view of a constant meshing starter. (Example 2) which is a half sectional view of a clutch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Starter 2 Motor 4 Planetary gear speed reducer 5 Output shaft 6 Pinion gear 7 Reverse rotation prevention clutch 11 Housing 14 Armature shaft 15 Armature core 23 Sun gear 25 Planetary gear 29 Ring gear 34 Clutch inner 35 Cam chamber 36 Clutch outer 36a Outer of clutch outer Part 36b Clutch outer fixing part 37 Roller (clutch member)

Claims (7)

A motor that generates rotational force on the armature shaft;
A planetary gear reducer for reducing the rotation of the armature shaft;
An output shaft to which the driving torque of the motor is transmitted via the reduction gear;
A pinion gear that is provided on the output shaft, always meshes with a ring gear on the engine side, and rotates integrally with the output shaft to drive the ring gear;
A reverse rotation preventing clutch that prevents the armature shaft from rotating in a direction opposite to that when the engine is driven;
The reverse rotation prevention clutch is disposed concentrically with the clutch inner provided on the armature shaft, and fixed to a housing or a yoke forming a magnetic circuit of the motor so as not to rotate. And a clutch outer that forms a wedge-shaped cam chamber with the clutch inner, and the cam chamber disposed in the cam chamber when rotation in a direction opposite to that during engine driving is transmitted to the armature shaft. A clutch member that moves in the narrow direction of the clutch and prevents rotation of the clutch inner,
The clutch inner is provided separately from the armature shaft, and is fixed to the outer periphery of the armature shaft by press fitting,
The armature shaft is formed with a sun gear that transmits the rotation of the armature shaft to the planetary gear of the speed reducer on the side opposite to the axial direction of the portion where the clutch inner is press-fitted (referred to as an inner press-fit portion). A starter characterized in that the outer diameter of the inner press-fit portion is larger than the outer diameter of the sun gear. A motor that generates rotational force on the armature shaft;
A planetary gear reducer for reducing the rotation of the armature shaft;
An output shaft to which the driving torque of the motor is transmitted via the reduction gear;
A pinion gear that is provided on the output shaft, always meshes with a ring gear on the engine side, and rotates integrally with the output shaft to drive the ring gear;
A reverse rotation preventing clutch that prevents the armature shaft from rotating in a direction opposite to that when the engine is driven;
The reverse rotation prevention clutch is disposed concentrically with the clutch inner provided on the armature shaft, and fixed to a housing or a yoke forming a magnetic circuit of the motor so as not to rotate. And a clutch outer that forms a wedge-shaped cam chamber with the clutch inner, and the cam chamber disposed in the cam chamber when rotation in a direction opposite to that during engine driving is transmitted to the armature shaft. A clutch member that moves in the narrow direction of the clutch and prevents rotation of the clutch inner,
The clutch inner is provided separately from the armature shaft, and is fixed to the outer periphery of the armature shaft by press-fitting and is in contact with an axial end surface of the armature core fixed to the armature shaft. A starter characterized by The starter according to claim 1 or 2,
A starter characterized in that serrations are provided on the outer periphery of the armature shaft into which the clutch inner is press-fitted or on the inner periphery of the clutch inner. In starter according to claim 1 or 2,
The starter characterized in that the surface hardness of the clutch inner is higher than the surface hardness of the armature shaft into which the clutch inner is press-fitted. In starter according to claim 1 or 2,
The clutch outer includes an outer portion that forms the cam chamber and a fixed portion that is fixed to the housing or a yoke that forms a magnetic circuit of the motor so as not to rotate, and the outer portion. Is fixed to the fixing portion. The starter according to claim 5 , wherein
The fixing portion is provided in a ring shape having a round hole,
The outer part is fixed to the round hole of the fixed part by press-fitting. The starter according to claim 6 , wherein
The clutch inner is fixed to the outer periphery of the armature shaft by press-fitting, and the sliding torque of the press-fitting part in which the outer part is press-fitted into the fixed part is larger than the sliding torque of the press-fitting part. Starter.

Images