JPH10238441A - Starter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure smooth movement of a pinion moving body by fixing a seal member slidably contacting with the pinion moving body, at the inner circumference of an opening formed at a front case, and providing, at inner circumference of the pinion moving body, a ventilation path of communicating spaces defined forward and rearward of a bearing with each other. SOLUTION: A seal member 40 is fixed at the inner circumference of an opening 7b formed at a front case 7 of a starter. The outer peripheral face of a cylindrical portion 35 of a pinion moving body 4 is brought into slide- contact with the inner circumferential face of the seal member 40, thus preventing dirty water or dust scraped up by rotation of a ring gear from intruding from the opening 7b into the front case 7. A ventilation path 41 for communicating a closed space A formed forward of a bearing 33 with an inside space formed rearward of the bearing 33 is provided at the inner circumference on the tip side of the pinion moving body 4 so that the closed space A is never turned into a tightly closed state. Consequently, the pinion moving body 4 can be smoothly moved, thereby enhancing mesh of a pinion gear 12 with the ring gear.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter for starting an engine.

[0002]

2. Description of the Related Art As a prior art, Japanese Patent Application Laid-Open No. 59-1826 is disclosed.
No. 3 discloses a starter. The starter includes a pinion moving body that fits in a helical spline around the output shaft, and a rotation restricting member that restricts the rotation of the pinion moving body. Is operated to restrict the rotation of the pinion moving body, whereby the pinion moving body is moved by the thrust generated in the helical spline, and the pinion gear provided on the pinion moving body meshes with the ring gear of the engine. In addition, this starter is provided with a lid for closing the front of the front end surface of the output shaft at the front end of the pinion moving body, and covers the outer periphery of the front end of the output shaft in a bag shape. It has an excellent structure and can prevent muddy water and dust from adhering to the outer peripheral surface of the output shaft.

[0003]

However, in the above-mentioned starter, since the bearing supporting the outer peripheral surface of the pinion moving body is exposed to the outside through the opening of the front case, it is lifted up by the rotation of the ring gear. Muddy water, dust and the like easily penetrate from the opening of the front case and reach the bearing. As a result, the oil content of the bearing is absorbed by the muddy water or dust, and the oil content of the bearing is lost, which may lead to poor sliding of the pinion moving body. In addition, since the space formed around the distal end of the output shaft at the inner periphery of the distal end side of the pinion moving body is sealed by the bearing, the pinion moving body cannot move smoothly, and the meshing property between the pinion gear and the ring gear deteriorates. There was a problem. The present invention has been made based on the above circumstances, and an object thereof is to smoothly move a pinion moving body in a starter having a structure in which the outer periphery of the tip end of an output shaft is covered in a bag shape by a pinion moving body. Therefore, it is to improve the meshing property between the pinion gear and the ring gear, and to prevent the bearing supporting the outer peripheral surface of the pinion moving body from running out of oil, thereby preventing poor sliding of the pinion moving body.

[0004]

According to the present invention, a seal member for slidingly contacting the outer peripheral surface of the cylindrical portion of the pinion moving body is fixed to the inner peripheral portion of the opening of the front case, so that the inner peripheral surface of the opening of the front case is fixed. Muddy water, dust, and the like can be prevented from entering the inside of the front case through a gap between the pinion moving body and the outer peripheral surface of the cylindrical portion. Also, by providing a ventilation path that communicates a closed space formed forward of the bearing and a space rearward of the bearing on the inner periphery of the pinion moving body that covers the outer periphery of the distal end of the output shaft in a bag shape, The space communicates with the internal space of the front case. As a result, air flows between the closed space and the internal space of the front case with the movement of the pinion moving body, so that the closed space is not closed. As a result, the pinion moving body can smoothly move on the output shaft, and good engagement between the pinion gear and the ring gear can be realized.

[0005] The vent passage can be formed by recessing the outer peripheral surface of the bearing or the inner peripheral surface of the pinion moving body into a groove shape. Alternatively, claim 3
As described in the above, it may be formed so as to pass through the inside of the output shaft and communicate with the internal space of the front case. Further, as described in claim 4, the pinion moving body has an outer peripheral surface behind the pinion gear rotatably supported by the front case via a bearing, and a seal member is disposed forward of the bearing. . In this case, the seal member can prevent muddy water, dust, and the like, which have been scraped up by the rotation of the ring gear, from entering the inside of the front case through the opening of the front case. This prevents muddy water, dust, and the like from adhering to the bearing located behind the seal member, and prevents the bearing from running out of oil, thereby preventing poor sliding of the pinion moving body.

[0006]

Next, a starter according to the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of the starter 1.
The starter 1 according to the present embodiment includes a machine frame (described later) that forms a substantially cylindrical outer shape. A start motor 2 that generates a rotational force, and a rotation of the start motor 2 are provided inside the machine frame. A planetary gear speed reducer (which will be described later) that reduces the speed, an output shaft 3 that rotates upon receiving the rotation output of the speed reducer, a pinion moving body 4 movably provided on the output shaft 3, and power supply to the starting motor 2. An electromagnetic switch 5 to be controlled, a rotation restricting member 6 for restricting rotation of the pinion moving body 4 before the starter motor 2 is energized, and the like are accommodated.

The machine frame includes a front case 7, a center case 8, a yoke 9, a brush holder 10,
It is composed of a rear case 11 and is entirely fixed by a plurality of through bolts (not shown). The front case 7 has a mounting surface 7a orthogonal to the output shaft 3, and is fixed to a side wall of the engine (for example, a clutch housing) via the mounting surface 7a. Further, an opening 7b for meshing a pinion gear 12 provided on the pinion moving body 4 with a ring gear 13 of the engine is provided on a front end face of the front case 7.

The starting motor 2 comprises a yoke 9, a fixed magnetic pole 14,
It is composed of an armature 15, a brush 16, and the like. Yoke 9
Is a part of the machine frame and a part of the magnetic circuit.
It is provided in a cylindrical shape. The fixed magnetic pole 14 uses a plurality of permanent magnets, and is fixed to the inner peripheral surface of the yoke 9 while maintaining a slight gap between the fixed magnetic pole 14 and the outer peripheral surface of the armature 15. Instead of the permanent magnet, a pole core may be fixed to the inner peripheral surface of the yoke 9 and a field coil may be wound around the outer periphery of the pole core. The armature 15 includes a rotating shaft 19 rotatably supported at both ends via bearings 17 and 18, an armature core 20 fixed to the outer periphery of the rotating shaft 19 and forming a part of a magnetic circuit,
An armature coil 21 provided in the armature core 20, a commutator 22 electrically and mechanically coupled to the armature coil 21, and the like.

The commutator 22 is provided on the rear side of the armature 15 (FIG. 1).
On the outer periphery of the rotating shaft 19, the insulating member 2
It is formed by combining a plurality of commutator pieces insulated by 2a into a cylindrical shape. The brush 16 is located on the radial outer periphery of the commutator 22 and is housed together with a spring 25 in a brush housing chamber 24 formed by the brush holder 10 and the plate 23. Has been energized. The brush 16 is disposed so as to be slidable in the brush storage chamber 24 in the radial direction (the vertical direction in FIG. 1), and is restricted from moving in the rotation direction of the armature 15. The brush holder 10 is arranged at the rear of the starting motor 2 and is sandwiched between the yoke 9 and the rear case 11. A bearing 17 that supports the rear end of the rotating shaft 19 is fixed to the radial center of the brush holder 10.

The reduction gear transmission includes a sun gear 26 (external teeth) formed on the outer periphery of one end of the rotating shaft 19, an internal gear 27 (internal teeth) arranged on a radial outer periphery of the sun gear 26,
It comprises a plurality of planetary gears 28 disposed between the sun gear 26 and the internal gear 27 and meshing with both gears 26, 27. The internal gear 27 is formed on a gear component 29 disposed on the inner periphery of the center case 8. The gear constituent member 29 includes a one-way clutch together with an inner cylindrical portion 8a formed in a cylindrical shape on the inner diameter side of the center case 8 and a roller 30 housed between the inner cylindrical portion 8a and the gear constituent member 29. With the function of the one-way clutch, the armature 15 cannot rotate with respect to the center case 8 in the rotation direction of the armature 15,
The armature 15 is provided so as to be rotatable in the anti-rotational direction.
The planet gear 28 is rotatably supported by a pin 31 press-fitted into a large-diameter portion 3 a provided on the outer periphery of the rear end of the output shaft 3, and a bearing 32 fitted on the outer periphery of the pin 31.

The output shaft 3 is arranged coaxially with the rotation shaft 19 and is fixed to the inner periphery of the tip end side of the pinion moving body 4.
3 and a bearing 34 fixed to the inner periphery of the inner cylindrical portion 8a of the center case 8 so as to be rotatable.
Is restricted in the axial direction. At the center of the rear end of the output shaft 3, a concave portion 3 b that is depressed in the axial direction is provided. A helical spline 3c (see FIG. 2) is provided on a part of the outer peripheral surface of the output shaft 3 that projects forward (to the left in FIG. 1) from the center case 8.

The pinion moving body 4 protrudes forward from the opening 7 b of the front case 7 and supports the outer periphery of the distal end of the output shaft 3 via the bearing 33.
2 and a helical spline 35a formed on the inner peripheral surface
(See FIG. 2) comprises a cylindrical portion 35 fitted on the helical spline 3c formed on the outer peripheral surface of the output shaft 3, and the pinion gear 12 and the cylindrical portion 35 are formed integrally.
The pinion gear 12 advances on the output shaft 3, meshes with the ring gear 13 of the engine, and transmits the torque of the starting motor 2 to the ring gear 13. The pinion gear 12 has a cover 36 in front of the distal end surface of the output shaft 3.
6 is formed integrally with the pinion gear 12 and is provided in a bottomed cylindrical shape that covers the outer periphery of the distal end portion of the output shaft 3 in a bag shape.
In the present invention, the one in which the lid portion 36 is integrally formed is proposed, but one manufactured separately from the pinion moving body 4 may be fixed for convenience in manufacturing.

The cylindrical portion 35 is provided to extend rearward from the pinion gear 12 in a cylindrical shape.
A flange portion 37 having a larger outer diameter is formed, and a large number of tooth portions 37 a (irregular portions) are provided on the outer periphery of the flange portion 37.
The outer diameter of the cylindrical portion 35 excluding the flange 37 is set slightly larger than the outer diameter of the pinion gear 12 and smaller than the outer diameter of the flange 37. In addition, on the rear end face of the flange 37,
A washer 38 is rotatably supported via a bearing 37b. However, the washer 38 has an outer diameter substantially equal to (or slightly smaller than) the root diameter of the tooth portion 37a.

As shown in FIG. 2, the pinion moving body 4 has an outer peripheral surface of a cylindrical portion 35 with an opening 7 of the front case 7.
b, is rotatably and slidably supported by a bearing 39 fixed to the inner periphery of the cylindrical member 35. The seal member 40 is fixed to the inner periphery of the opening 7b of the front case 7 in front of the bearing 39. The outer peripheral surface is in sliding contact. Further, on the inner peripheral surface of the pinion moving body 4 to which the bearing 33 is fixed, there is formed a ventilation path 41 which is recessed in a groove shape along the axial direction over a distance longer than the axial length of the bearing 33. . This air passage 41 is provided on the output shaft 3.
A closed space A formed forward of the bearing 33 on the inner periphery of the pinion moving body 4 covering the outer periphery of the distal end portion in a bag-like shape and an inner space B behind the bearing 33 communicate with each other. Also, the bearing 33
The inner space B on the rear side communicates with the inner space C of the front case 7 through a meshing gap between the helical spline 3c of the output shaft 3 and the helical spline 35a of the tubular portion 35. The air passage 41 is provided with the pinion moving body 4.
At least one location in the circumferential direction.

As shown in FIG. 2, an elastic member 42 such as a disc spring is mounted on the outer peripheral surface of the cylindrical portion 35 of the pinion moving body 4 behind the bearing 39 by being sandwiched between a pair of washers 43 and 44. ing. A collar 45 for restricting the forward movement of the pinion moving body 4 is attached to the rear side of the washer 44. The collar 45 for constantly biasing the pinion moving body 4 rearward between the collar 45 and the flange 37 is provided. A spring 46 is attached. The elastic member 42 and the pair of washers 4
The reference numerals 3, 44 and the collar 45 are mounted on the pinion moving body 4 so as to be rotatable and slidable in the axial direction, respectively. However, the washer 43 on the front side of the elastic member 42 is
Abutment on the inner wall surface 7c of the front case 7 (a wall surface formed at a substantially right angle from the rear end of the inner peripheral surface of the opening 7b) restricts the axial forward movement.

The electromagnetic switch 5 is disposed behind the brush holder 10 and is housed inside a bowl-shaped rear case 11. The electromagnetic switch 5 includes a cylindrical frame 47 having an opening in the center of the bottom surface, and a ground plate 4 fixed by caulking to the opening end of the frame 47.
8, a suction coil 49 accommodated in the frame 47, a plunger 50 and the like arranged so as to be able to move up and down the inner periphery of the suction coil 49 through an opening of the frame 47, etc., with the movement of the plunger 50 A motor contact (described below) interposed in the energizing circuit of the starting motor 2 is opened and closed.

The frame 47, the ground plate 48, and the plunger 50 are provided by magnetic materials, respectively, and constitute a magnetic circuit of the electromagnetic switch 5. The plunger 50 faces the ground plate 48 via an air gap at the inner periphery of the suction coil 49, and when the suction coil 49 is energized and a magnetic flux flows through the magnetic circuit, the plunger 50
Due to the magnetic force acting between the plunger 8 and the plunger 50, the plunger 50 is attracted and moved toward the ground plate 48 (upward in FIG. 1).

As shown in FIG. 3, the motor contacts include a battery-side fixed contact 51, a motor-side fixed contact 52, and a movable contact 53. The battery-side fixed contact 51 is connected to the rear case 1 above the operating direction of the plunger 50 (vertical direction in FIG. 1).
1 and is provided integrally with a battery terminal 54 taken out of the rear case 11. The battery terminal 54 is fixed to the rear case 11 by a washer 55, and is connected to a battery 57 mounted on the vehicle through a cable 56. The motor-side fixed contact 52 is fixed to the inner wall surface of the rear case 11 along with the battery-side fixed contact 51, and is electrically connected to the positive brush 16 via a lead wire 58.

The movable contact 53 is a fixed contact 51 on the battery side.
And the plunger 50 facing the motor-side fixed contact 52.
It is attached via an insulating member 60 to an end of a rod 59 provided integrally with the plunger 50 and is movably provided with the plunger 50. The rod 59 protrudes upward from the center of the upper end surface of the plunger 50 through a through hole (no reference numeral) opened in the center of the ground plate 48, and the movable contact 53 is attached to the upper end thereof. Also,
A contact spring 61 for biasing the movable contact 53 is provided on the outer periphery of the rod 59. The contact spring 61 includes a movable contact 53 having two fixed contacts 51, 5.
2, a required contact pressure (contact pressure on both fixed contacts 51, 52) is applied to the movable contact 53.

The rotation restricting member 6 is formed, for example, by winding a metal rod into a coil shape and bending both ends 6a and 6b of the rod in the same direction at substantially right angles. The rotation restricting member 6 includes a plate 62 whose coiled portion is fixed to the end face of the center case 8 and the front side of the center case 8.
Are arranged in a flat space formed between
1 is provided so as to be movable in the vertical direction in FIG. 1, and is constantly urged upward by a spring 63 fixed to a plate 62. The rotation restricting member 6 is connected to the plunger 50 of the electromagnetic switch 5 through a connecting member 64 such as a wire. When the attraction force of the electromagnetic switch 5 is transmitted through the connecting member 64, the rotation of the spring 63 is stopped. When the electromagnetic switch 5 moves downward in FIG. 1 against the urging force and the attraction force of the electromagnetic switch 5 disappears, it is pushed back to the initial position (the position shown in FIG. 1) by the urging force of the spring 63.

Both ends 6a, 6b bent at right angles
Are taken out of the plate 62 through openings (not shown) provided in the plate 62, respectively. One end 6a is located radially above the output shaft 3 and on the outer periphery of the teeth 37a of the flange 37, and the other end 6b
Is located radially below the output shaft 3 behind the rear end surface of the washer 38 provided on the flange portion 37. However, the one end portion 6a moves the pinion moving body 4 forward on the output shaft 3 by a predetermined distance (for example, the pinion moving body 4 has moved to a position where the end face of the pinion gear 12 contacts the end face of the ring gear 13). Also, the length is set so that the rotation restricting member 6 can be engaged with the teeth 37 a provided on the outer periphery of the flange 37 when the rotation restricting member 6 moves downward due to the attraction force of the electromagnetic switch 5.

When the radial distance between one end 6a and the outer peripheral surface of the tooth portion 37a is L1, and the distance between the movable contact 53 of the electromagnetic switch 5 and both fixed contacts 51 and 52 is L2, Is set so that the following relationship is established. L1 ≤
L2 This allows the electromagnetic switch 5 to start the motor 2
Before the power is supplied (the movable contact 53 is connected to the fixed contacts 51 and 52).
Before the contact, the one end 6a is engaged with the tooth 37a to restrict the rotation of the pinion moving body 4.

Next, the operation of this embodiment will be described. When the key switch 65 (see FIG. 3) is closed, a current flows from the battery 57 to the attraction coil 49 of the electromagnetic switch 5 to generate a magnetic force, and the plunger 50 is attracted and moved upward in FIG. This movement of the plunger 50 pulls the other end 6b of the rotation restricting member 6 downward through the connecting member 64, so that the entire rotation restricting member 6 moves downward in FIG.
As a result, one end 6a of the rotation restricting member 6 is
The pinion 37 engages with a tooth portion 37 a provided on the outer periphery of the pinion 7 to restrict the rotation of the pinion moving body 4.

On the other hand, the electromagnetic switch 5 includes a plunger 50
When the movable contact 53 comes into contact with the fixed contacts 51 and 52 due to the movement, current flows from the battery 57 to the armature 15 and the armature 15 rotates. After the rotation of the armature 15 is decelerated by the reduction gear, it is transmitted to the output shaft 3 and the output shaft 3 rotates. The rotation of the output shaft 3 also causes the pinion moving body 4 to rotate. However, since the rotation of the pinion moving body 4 is restricted as described above, the rotation of the output shaft 3 is controlled by the helical spline 3c and the helical spline 35a.
And acts as a thrust on the pinion moving body 4 through meshing with the pinion moving body 4.

Thus, the pinion moving body 4 is connected to the output shaft 3
Move up. At this time, as the pinion moving body 4 advances, the closed space A formed forward of the bearing 33 on the inner periphery at the distal end side of the pinion moving body 4 is in a negative pressure state. Air flows into the closed space A through the air gap 41 formed on the inner peripheral surface of the pinion moving body 4 → the internal space B behind the bearing 33 → the meshing gap between the helical spline 3c and the helical spline 35a (arrow shown in FIG. 2). Therefore, the pinion moving body 4 can move (forward) on the output shaft 3 smoothly.

When the pinion gear 12 meshes with the ring gear 13 due to the advance of the pinion moving body 4, the starting motor 2
Is transmitted from the pinion gear 12 to the ring gear 13 to rotate the ring gear 13 to start the engine. The pinion moving body 4 moving forward on the output shaft 3 stops when the end face of the flange 37 collides with the collar 45 mounted on the outer periphery of the cylindrical portion 35. It is alleviated by the deformation of the elastic member 42.
When the pinion gear 12 meshes with the ring gear 13, one end 6a of the rotation restricting member 6 is disengaged from the teeth 37a of the flange 37, and a washer 38 provided on the rear end face of the flange 37.
The pinion moving body 4 is restricted from retreating by falling behind.

When the key switch 65 is opened after the engine is started, the current to the suction coil 49 is cut off and the plunger 50 is turned off.
1 is extinguished, the rotation restricting member 6 is pushed back upward in FIG. 1 by the urging force of the spring 63 and returns to the initial position (the position shown in FIG. 1). As a result, the plunger 50 is pulled downward through the connecting member 64, so that the movable contact 53 separates from the fixed contacts 51 and 52 with the movement of the plunger 50, and the power supply to the armature 15 is cut off. Rotation stops.

When the rotation restricting member 6 is pushed back upward, one end 6a of the rotation restricting member 6, which has restricted the retraction of the pinion moving body 4 until then, comes off the rear end face of the washer 38. The retraction control of the moving body 4 is released. As a result, the pinion gear 12 is separated from the ring gear 13 by the urging force of the spring 46, and the pinion moving body 4 moves backward on the output shaft 3. At this time, the air in the closed space A formed forward of the bearing 33 on the inner periphery at the distal end side of the pinion moving body 4 is compressed as the pinion moving body 4 retreats. Air is pushed back to the internal space C of the front case 7 through the ventilation path 41 formed on the inner peripheral surface of the inner case 4, the internal space B behind the bearing 33, and the meshing gap between the helical spline 3c and the helical spline 35a (FIG. The pinion moving body 4 can smoothly move (retreat) on the output shaft 3 and return to the rest position (the position shown in FIG. 1).

(Effect of this embodiment) In this embodiment, a seal member 40 is fixed to the inner periphery of the opening 7b of the front case 7, and the cylindrical portion of the pinion moving body 4 is fixed to the inner periphery of the seal member 40. By adopting a structure in which the outer peripheral surface of 35 is in sliding contact,
It is possible to prevent muddy water, dust, and the like, which have been scraped up by the rotation of the ring gear 13, from entering the inside of the front case 7 through the opening 7 b of the front case 7. As a result, muddy water, dust and the like do not adhere to the bearing 39 disposed behind the seal member 40, and the oil content of the bearing 39 can be prevented from being absorbed by the muddy water and dust. Poor sliding of the pinion moving body 4 can be prevented.

Further, by providing a ventilation path 41 for communicating between a closed space A formed on the inner periphery of the distal end side of the pinion moving body 4 in front of the bearing 33 and an internal space B on the rear side of the bearing 33, The closed space A and the internal space C of the front case 7 communicate with each other. As a result, air flows between the closed space A and the internal space C of the front case 7 with the movement of the pinion moving body 4, so that the closed space A does not become a closed state. As a result, the pinion moving body 4 can smoothly move on the output shaft 3, and the pinion gear 12 and the ring gear 1
3 can be realized.

(Second Embodiment) FIG. 4 is a sectional view of the starter 1. The present embodiment shows an example in which the air passage 41 is formed on the output shaft 3. The ventilation passage 41 has a ventilation hole 41a which penetrates in an axial direction from a front end surface of the output shaft 3 to a concave portion 3b provided at a rear portion of the output shaft 3, and an output shaft 41 provided behind the helical spline 3c (before the center case 8). 3 through holes 41b penetrating in the radial direction. Therefore, the closed space A formed on the inner circumference at the distal end side of the pinion moving body 4 and forward of the bearing 33 communicates with the internal space C of the front case 7 through the ventilation holes 41a and 41b.

Thus, the pinion moving body 4 is connected to the output shaft 3
When moving forward, the air flows into the closed space A from the internal space C of the front case 7 through the ventilation hole 41b → the ventilation hole 41a, so that the pinion moving body 4 can smoothly move the output shaft 3
You can move up (forward). On the other hand, when the pinion moving body 4 retreats on the output shaft 3, air is pushed back from the closed space A to the internal space C of the front case 7 through the ventilation holes 41a → the ventilation holes 41b.
Can smoothly move (retreat) on the output shaft 3.

(Modification) In the above embodiment, the air passage 41 is formed on the inner peripheral surface of the pinion moving body 4, but may be formed on the outer peripheral surface of the bearing 33. Alternatively, it may be formed on both the inner peripheral surface of the pinion moving body 4 and the outer peripheral surface of the bearing 33. In the above embodiment, the pinion gear 12 and the cylindrical portion 35 of the pinion moving body 4 are provided integrally, but may be formed separately.
However, in this case, it is necessary to restrict the rotation so that the pinion gear 12 and the cylindrical portion 35 cannot rotate relative to each other (that is, the pinion gear 12 and the cylindrical portion 35 rotate integrally).

[Brief description of the drawings]

FIG. 1 is a sectional view of a starter (first embodiment).

FIG. 2 is an enlarged sectional view around a pinion moving body (first embodiment)
Example).

FIG. 3 is an electric circuit diagram of a starting motor (first embodiment).

FIG. 4 is a sectional view of a starter (second embodiment).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Starter 2 Start motor 3 Output shaft 3c Helical spline (output shaft) 4 Pinion moving body 7 Front case 7b Opening 12 Pinion gear (pinion moving body) 13 Ring gear 33 Bearing 35 Cylindrical part (pinion moving body) 35a Helical spline (cylinder) 39) Bearing 40 Sealing member 41 Vent 41a Vent (vent) 41b Vent (vent) A Closed space B Internal space (space behind the bearing) C Internal space of front case

Claims (4)

[Claims] 1. A starting motor for generating a rotational force, an output shaft rotatably driven by the starting motor, and a bottomed cylindrical shape which covers the outer periphery of the tip of the output shaft in a bag-like shape. A pinion gear that meshes with the ring gear of the engine is formed on the outer periphery of the cylindrical distal end portion, fitted to the outer peripheral portion of the output shaft via a bearing, and provided on the outer periphery of the output shaft via a helical spline behind the bearing. A pinion moving body to be fitted, and a front case that covers an outer periphery of the pinion moving body and is provided with an opening for projecting the pinion gear, and the rotation of the pinion moving body before the starting motor is energized. A starter that moves the pinion moving body along the helical spline by restricting the front case. A seal member that slides on the outer peripheral surface of the cylindrical portion of the pinion moving body behind the pinion gear, and the inner periphery of the pinion moving body that covers the outer periphery of the distal end portion of the output shaft in a bag shape, is located forward of the bearing. A ventilating passage for communicating a closed space formed at the rear side with a space behind the bearing. 2. The starter according to claim 1, wherein the ventilation path is formed by recessing an outer peripheral surface of the bearing or an inner peripheral surface of the pinion moving body into a groove. 3. The starter according to claim 1, wherein the ventilation path communicates with the internal space of the front case through the inside of the output shaft. 4. The pinion moving body according to claim 1, wherein an outer peripheral surface behind the pinion gear is rotatably supported by the front case via a bearing, and the seal member is disposed forward of the bearing. The starter according to any one of claims 1 to 3, wherein