# Patent

## Title
Drive mechanism for adjusting parts in furniture for sitting and lying down

## Abstract

To fully secure the precision around an output shaft, an electromagnet is axially held in position between a center bracket and a front bracket which form an enclosing member for a starter.

## Background
1. Field of the Invention

The present invention relates to a starter for starting an engine.

2. Description of the Prior Art

FIG. 9 is a sectional view showing one example of a conventional starter disclosed in Japanese laid-Open Patent Application (Kokai) No. Hei 10-159692.

In FIG. 9, 1A is an output shaft. Coaxially arranged on this output shaft 1A are an electromagnet 2A, an overrunning clutch 30A provided with a pinion 30P adapted to engage with a ring gear 50A, a plunger 40A consisting of an inner plunger 4A and an outer plunger 4B, etc. A starter with this structure is generally called a coaxial type starter.

Reference numeral 12A is an armature of a DC motor and 16A is a shaft (a motor shaft). Numeral 18A is a deceleration mechanism for decelerating the torque of the shaft 16A and transmitting it to the output shaft 1A.

8A is a contact shaft which is supported by an internal gear member 17A of the deceleration mechanism 18A substantially parallel with the plunger 40A through a supporting hole 17m.

100 is a front bracket, 130 is a yoke, 400 is a rear bracket, and 800 is a shift plate which connects the outer plunger 4B to the contact shaft 8A.

The upper side from the central axis in FIG. 9 shows the state of a starter not in operation and the lower side from the central axis in FIG. 9 shows the state where the starter is in operation with an electromagnet turned ON and the pinion engages the ring gear.

In this starter, when an ignition switch is turned ON and an electric current flows to an exciting coil of the electromagnet 2A, the outer plunger 4B is attracted by an exciting core 2C of the electromagnet 2A. This conventional starter has such a structure that the outer plunger 4B is directly connected to the contact shaft 8A through the shift plate 800 and the contact shaft 8A also moves at the same time when the outer plunger 4B is attracted and moved by the exciting coil 2B. A coil spring 401 is disposed between the outer plunger 4B and the inner plunger 4A through a spring bearing member 401S. The inner plunger 4A is kept in the resting state because the coil spring 401 bends at the initial stage even when the outer plunger 4B starts the movement by attraction. Disposed in front of the inner plunger 4A through a shifter member 402 is an inner clutch 30B, which is also kept in the resting state while the inner plunger 4A is kept in the resting state. After a short interval when the outer plunger 4B starts the movement by attraction, a moving contact 80A mounted on the contact shaft 8A comes into contact with a stationary contact 80B disposed in a contact chamber ZA. When the moving contact 80A contacts with the stationary contact 80B, electric power is supplied from an external power source through a contact bolt 11A to start rotation of the armature 12A. When the output shaft 1A starts to turn through the deceleration mechanism 18A, the pinion 30P starts to move toward the ring gear 50A by the thrust generated in a helical spline portion 1B. Then, the crest and root of the pinion 30P agree and engage with those of the ring gear 50A. Thereafter, when the engine starts, the output shaft 1A is separated from the pinion 30P by the action of the overrunning clutch 30A and the pinion 30p runs idle. When the power supply to the exciting coil 2B is stopped, the pinion 30P is disengaged from the ring gear 50A by return springs 403, 404.

Further, the conventional electromagnet is assembled as shown in Japanese Laid-Open patent Application (Kokai) No. Hei 10-159692 etc. This is explained by taking the conventional starter as shown in FIG. 9 for instance. When the electromagnet 2A is mounted on the front bracket 100, a switch case 2k enclosing the exciting coil 2B is press-fitted direct or through another member such as rubber and resin to an electromagnet housing portion 110 of the front bracket 100.

As described above, the conventional electromagnet 2A of the starter is press-fitted to the electromagnet-housing portion 110 of the front bracket 1005 and assembled to control the radial movement, but since no axial control is provided, there is the possibility that the electromagnet 2A is caused to axially move by some vibration etc. and as a result, it gets out of the normal position (the switch-housing portion 110).

To prevent this problem, when the electromagnet 2A is mounted on the front bracket 100 according to a method as shown in FIGS. 10 and 11, the switch case 2K enclosing the exciting coil 2B is first inserted into the electromagnet housing portion 110. It is then fixed by crimping the open end G (the side of the deceleration mechanism 18A) of the front bracket 100 as shown by a mark F. According to this method, it is possible to prevent the electromagnet 2A from axially getting out of the normal position (the switch-housing portion 110) by crimping the open end G of the front bracket 100. However, in this case, there is added a process of crimping, and manufacturing costs are higher.

Also, when the inner components are assembled in the conventional starter as shown in FIG. 10, the overrunning switch 30A and a shaft section 1AK of the output shaft 1A on which the sliding surface (a helical spline) for the overrunning switch 30A is formed are first installed in the front bracket 100. Then, the electromagnet 2A is inserted into the switch-housing portion 110 of the front bracket 100 and secured in place by crimping. After this, it was necessary for a group of components pre-installing the plunger 4a, the deceleration mechanism 18A including a flange section 1AF of the output shaft 1A, and a contact chamber ZA including the contact shaft 8A to be assembled as a unit (The starter of FIG. 9 is also assembled in the same manner as this).

Namely, in this case, it is necessary to use the shaft section 1AK and the flange section which are separated in advance for the output shaft 1A (Namely, as shown in FIG. 6, once the output shaft integrally provided with a shaft section and a flange section is assembled first, it is impossible to coaxially mount the overrunning clutch 30A, the electromagnet 2A, the plunger 4a, etc. on the output shaft 1A).

In this case, when the output shaft 1A is formed by combining the shaft section 1AK with the flange section 2AF, press fitting or crimping is the only way to combine them each other. Since this causes the eccentricity of the shaft by deformation, it is difficult to secure the accuracy of squareness etc. of the shaft portion lAK and the flange portion 1AF. There is also a problem that the accuracy around the output shaft of the starter cannot be secured.

It is therefore an object of the present invention to solve such problems as mentioned above and to provide a starter which does not require any extra process (a crimping process) and can reduce manufacturing costs as well.

It is another object to provide a starter in which the precision around an output shaft is fully secured and further provide a manufacturing method of the starter which can realize the objects as described above.

According to the present invention, a starter is provided in which an electromagnet is axially held in position between a center bracket and a front bracket which serve as an enclosing member for the starter.

Also, a starter installation method according to the present invention comprises the steps of: the flange section on a motor through a deceleration mechanism which is combined with the flange section;

where the electromagnet is held between the front bracket and the center bracket; and fastening a bolt so that the electromagnet can be secured between the front bracket and the center bracket.

The above and other objects, features and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings.

FIG. 1 is a cross-sectional view showing the structure of a starter according to a first embodiment of the present invention;

FIG. 2 is an enlarged view showing an important part of FIG. 1;

FIG. 3 is an enlarged view of an important part of the starter according to a second embodiment of the present invention;

FIG. 4 is cross-sectional view of a deceleration mechanism;

FIG. 5 is a cross-sectional view of an overrunning clutch;

FIG. 6 is a perspective view of an output shaft;

FIG. 7(a) and (b) are perspective views of the overrunning clutch;

FIG. 8 is a perspective view of a plunger and a shift plate;

FIG. 9 is a cross-sectional view showing one example of a conventional starter;

FIG. 10 is a cross-sectional view for explaining an installation method of an electromagnet of the conventional starter; and

FIG. 11 is an enlarged view showing an important part of FIG. 10.

1st Embodiment

A first embodiment of a starter according to the present invention will be explained hereunder with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing a structure of the starter according to a first embodiment. The left side of FIG. 1 is a DC motor section X, the right side is an operating section Y, and the upper portion of the substantially central side is a contact chamber Z, respectively. The motor side of FIG. 1 is referred to as the rear and the side of a ring gear is referred to as the front in the following explanation for convenience.

The starter according to the first embodiment is covered by such outer peripheral members for the starter as a front bracket 20, a center bracket 30, a yoke 13 and a rear bracket 40 and presents the substantially bullet-shaped external appearance. A portion into which a ring gear 50 is inserted is an opening.

In the starter, there are arranged a DC motor M and an output shaft 1 driven by this DC motor M. Arranged around this output shaft 1 are an annular electromagnet 2, an overrunning clutch 3, a plunger (a movable core) 4, etc.

In other words, the starter according to the first embodiment is a coaxial type starter with the electromagnet 2, the overrunning clutch 3 and the plunger 4 coaxially arranged on the output shaft 1.

The starter according to the first embodiment will be assembled as follows.

The contact chamber Z including a contact shaft 8 is secured to the pre-assembled DC motor section X. Then, the output shaft 1 is secured to a shaft 16 of the motor through the deceleration mechanism 18. The plunger 4 including a shift plate 7 is coaxially secured on the output shaft 1. The center bracket 30 with the electromagnet 2 built-in is coaxially secured on the output shaft 1. Then, the overrunning clutch 3 is spline-connected to the output shaft 1. Thereafter, the front bracket 20 is caused to engage with the center bracket 30 through an engaging portion 23 for final fastening by a through-bolt 41.

By fastening the through-bolt 41, the DC motor section X and the operating section Y are fixedly held in position between the rear bracket 40 and the front bracket 20 and thus the assembling of the starter is completed. When the through-bore 41 is fastened, the axial force is caused to axially secure the front bracket 20 and the center bracket 30 and as a result, the electromagnet 2 disposed between both brackets 20 and 30 is held in position. Thus, the electromagnet 2 is firmly secured both axially and radially and the axial misregistration is not caused even in case of vibration etc.

In other words, an exciting coil 2a and an exciting core 2c are enclosed by a switch case 2b. The cylindrical and pre-assembled electromagnet 2 which is coaxially arranged on the output shaft 1 is firmly held in position between a recess 30x formed on the center bracket 30 and a recess 20X formed on the front bracket 20 as shown in FIG. 2.

Also, a peripheral side 2n of one end 2e of the electromagnet 2 is caused to come in direct contact with a wall surface 30n of the recess 30X of the center bracket 30. A peripheral side 2m in the other end 2f is arranged to contact with a wall surface 20n of the recess 20X through a rubber packing 70c serving as a cushioning material.

Specifically, a section of the center bracket 30 corresponding to the peripheral side of one end of the electromagnet 2 is formed with the recess 30X adapted to control the movement of the electromagnet 2 in both axial and radial directions. The electromagnet 2 is pre-installed in the center bracket 30 by press-fitting one end 2e of the electromagnet 2 within this recess 30 X by means of an exclusive press-fitting machine. Also, as shown in FIG. 1, this recess 30X is formed except the section where the contact shaft 8 is arranged.

Thus, the electromagnet 2 is finally assembled by causing the peripheral side 2m of the other end 2f of the electromagnet 2 to contact with the wall surface 20n of the recess 20X of the front bracket 20 through the rubber packing 70c and then fastening the through-bolt.

According to the first embodiment, it is possible to easily assemble the electromagnet 2 without adding any caulking (crimping) process and without axial misregistration, and further possible to reduce the manufacturing cost.

Although the conventional starter has only one front bracket, there are provided two independent brackets of the front bracket 20 and the center bracket 30 in the present embodiment so that the electromagnet 2 can be installed from the front side of the output shaft 1. Accordingly, it is no longer necessary to divide the output shaft 1 into two sections of a shaft section which is provided with a helical spline 1a for causing a thrust spline 3A of an overrunning clutch 3 to slide thereon, and a flange section forming the deceleration mechanism. As shown in FIG. 6, it is possible to use the output shaft 1 which is integrally formed with the flange section 1F. Therefore, it is possible to secure the precision around the output shaft 1 and in particular, possible to fully secure the squareness between the shaft section and the flange section 1F and further possible to secure a reliable starter.

The peripheral side 2m of the other end 2f of the electromagnet 2 is arranged to come into contact with the front bracket 20 through the rubber packing 70c. It is therefore possible to hold both the electromagnet 2 and the front bracket 20 in position even when there is a little axial error in the geometry of the electromagnet 2 or the dimension of the recess 20X formed on the front bracket 20.

Since the electromagnet 2 is secured in position through the rubber packing 70c, it is advantageous to vibration proof.

Further, since the press-fitting overlap width h for controlling the periphery of the electromagnet 2 in the radial direction can be shortened, it is not necessary to increase the capacity of the press-fitting machine over and above what is wanted.

2nd Embodiment

As shown in FIG. 3, it is also possible to cause the other end 2f of the electromagnet 2 to come into direct contact with the front bracket 20 and secure one end 2e to the center bracket 30 through a packing 70d.

In other words, the peripheral side of one end 2e of the electromagnet 2 is held in the recess 30Y of the center bracket 30 through the rubber packing 70d.

Then, the section of the front bracket 20 corresponding to the peripheral side of the other end 2f of the electromagnet 2 is provided with a recess 20Y adapted to control the movement of the electromagnet 2 in both the axial and radial directions. The other end 2f of the electromagnet 2 is press-fitted into the recess 20Y by means of the exclusive press-fitting machine and thus the front bracket 20 is secured to the electromagnet 2.

The electromagnet 2 is finally kept in position by fastening the through-bolt 41.

It is to be noted that the second embodiment can get the same effect as the first embodiment.

When the above-mentioned first and second embodiments are put into practice, to assure the positioning of the electromagnet 2 in the radial direction, it is desirable to press-fit the periphery of a switch case on the end of the electromagnet 2 coming in direct contact with the bracket into the recess formed on the bracket. However, when the press-fitting overlap width h is too large, it is inevitable to increase the capacity of the press-fitting machine over and above what is wanted. Therefore, when the axial press-fitting overlap width is longer, as shown in FIG. 3, it is efficient to make a section 20S of the bracket recess larger than the periphery of the switch case 2b in advance.

It is also possible to use other materials such as resin for the cushioning materials in addition to the rubber.

The starter according to the present invention will now be described in detail below with reference to FIG. 1 and FIGS. 4 through 8.

As is well known, the DC motor comprises an armature 12, a yoke 13 enclosing the armature 12, a stationary magnetic pole 13a disposed inside this yoke 13, a commutator 14, brushes 15, and a shaft 16. The armature 12 is an armature core with an armature coil wound round it. The front side of the shaft 16 penetrates the cylindrical space of the cylindrical commutator 14 and is connected to a deceleration mechanism 18.

The armature coil is connected to the commutator 14. The DC motor is available in 2-pole, 4-pole and 6-pole types depending on the number of the stationary magnetic poles. For instance, taking the case of using a 6-pole DC motor as a sample, a total of 6 units of the stationary magnetic pole 13a by arranging a N-pole and a S-pole alternately. The brushes 15 kept in contact with the commutator 14 are arranged along the circumference of the commutator 14.

Reference numeral 15a is a spring that pushes the brushes 15 against the commutator 14. Numeral 15h denotes a brush holder.

The DC motor M as described above drives an output shaft 1.

The operating section Y comprises a deceleration mechanism 18, the output shaft 1, an electromagnet 2, an overrunning clutch 3, and a plunger 4. etc.

17 is an inner gear member. This member comprises a first tubular portion 17a fitted to the outer circumference of the output shaft 1 through a bearing 1y, a hollow disk-shaped bottom plate portion 17b extending in the direction perpendicular to the outer circumference of the output shaft 1 from the first tubular portion 17a, and a second tubular portion 17c extending in the rear side from the outer circumference edge of the bottom plate portion 17b and having an inner gear 18c on the inner circumference.

The deceleration mechanism 18 comprises the inner gear 18c of the inner gear member 17, a sun gear 18a provided on the shaft 16, a plurality of planet gears 18b arranged around this sun gear 18a and engaging with the sun gear 18a and the inner gear 18c, and pins 1P which projects from a flange section 1F of the output shaft 1 inserted between the group of planet gears 18b and the bottom plate portion 17b of the inner gear member 17 and connects each of the planet gears 18b to the flange section 1F of the output shaft 1. The rotational force of each planet gear 18b is transmitted to each pin 1p through a bearing 1z.

A round groove 1h is formed at the center of the flange portion 1F of the output shaft 1 and the forward end of the shaft 16 is rotatably supported through a bearing 1x provided in the round groove 1h.

Accordingly, as shown in the cross-sectional view of FIG. 4, when each planet gear 18b moves around the sun gear 18a, the rotational force of the shaft 16 is decelerated and transmitted to the output shaft 1 through the pins 1P.

A helical spline 1a is formed on a part of the outer circumference at the central side of the output shaft 1. On the outer circumference of the part where this helical spline 1a is formed, the overrunning clutch 3 is arranged so that a tubular portion 3a of a thrust spline 3A corresponds thereto. Further, formed on the inner surface of the tubular portion 3a of the thrust spline 3A is a helical spline 3x to engage with the helical spline 1a. That is, the overrunning clutch 3 is spline-connected to the output shaft 1.

The electromagnet 2 is arranged on the outer circumference of the tubular portion 3a of the thrust spline 3A.

The plunger 4 is arranged on the outer circumference on the flange 1F side of the output shaft 1.

The overrunning clutch 3 comprises the thrust spline 3A provided with a tubular portion 3a and a flange portion 3b, a roller cam 3c, a pinion 3P, an inner clutch 3y, a clutch roller 3r and a spring 3s, and a clutch cover 3w. The tubular portion 3a of the thrust spline 3A is provided on the inner surface with the helical spline 3x adapted to engage with the helical spline 1a formed on a part of the outer circumference on the central side of the output shaft 1. The flange portion 3b is formed on the front side of the tubular portion 3a and serves as the cam bottom of the roller cam 3c. The roller cam 3c is kept in position between the flange portion 3b and a washer 3e of the thrust spline 3A. The inner clutch 3y forms a tubular portion of the base of the pinion 3P. The clutch roller 3r and the spring 3s are disposed in a groove 3t formed on the roller cam 3c. The clutch cover 3w is arranged to cover the outside of the flange portion 3b, the roller cam 3c and the washer 3e of the thrust spline 3A.

The thrust spline 3A and the roller cam 3c form an outer clutch 3B.

The overrunning clutch 3 acts as a so-called one-way clutch. FIG. 5 shows a cross-sectional view of the overrunning clutch 3. Formed at several points on the inner circumference of the roller cam 3c are grooves 3t which form a narrow space and a wide space between the inner circumference of the roller cam 3c and the outer circumference of the inner clutch 3y. The clutch roller 3r is disposed in each of the grooves 3t. 3s is the spring for pressing the clutch roller 3r toward the narrow space of the grooves 3t.

When the output shaft 1 is driven by the DC motor M, the roller cam 3c is caused to rotate to move the clutch roller 3r toward the narrow space. Then, the roller cam 3c of the outer clutch 3B engages with the inner clutch 3y to rotate the pinion 3P, which engages with a ring gear 50. Once the pinion 3p is rotated by the ring gear 50, the clutch roller 3r is caused to move toward the wide space of the grooves 3t, and the outer clutch 3B and the inner clutch 3y are disengaged to separate the overrunning clutch 3 from the engine.

The electromagnet 2 comprises the exciting coil 2a, the switch case 2b for covering the exciting coil 2a, and the core 2c, and is arranged at the rear side of the position of the overrunning clutch 3B. The core 2c has a hollow-shaped disc surface opposing the flange portion 3b of the thrust spline 3A and is made in the annular body arranged so as to penetrate the outer circumference of the tubular portion 3a of the thrust spline 3A. The core 2c also has annular projection 2t extending to the rear side at the tubular portion 3a side of the thrust spline 3A.

The plunger 4 is made of a tubular body that is arranged in a movable manner between the inner circumference of the switch case 2b and the tubular portion 3a of the thrust spline 3A. The front end 4t of the plunger 4 opposing the annular projection 2t of the core 2c is formed in a shape corresponding to the shape of the annular projection 2t. An annular plate 5a serving as a first pressing plate is secured on the inner circumference on the rear end of the plunger 4. In addition, an annular plate 5b serving as a second pressing plate is provided on the rear end of the tubular portion 3a of the thrust spline 3A of the overrunning clutch 3. Arranged between these plates 5a and 5b, that is, between the inner circumference of the plunger 4 and the outer circumference of the output shaft 1 is a coil spring 6 serving as an elastic means.

Accordingly, the plunger 4 is attracted by the core 2c to move in the direction (forward) of the core 2c, and the overrunning clutch 3 moves as pushed by the plate 5b with the movement of the plunger 4. When the pinion 3P once stops moving after the end surface is brought into contact with the end surface of the ring gear 50, the motor is driven. When the crests and roots of the pinion 3P fit those of the ring gear 50, the pinion 3P engages with the ring gear 50 by the elastic force of the coil spring 6.

8 is a contact shaft which is movably supported in the extended direction of the shaft by a supporting hole 17h provided on a part (the upper part in FIG. 1) of a second tubular portion 17c of the inner gear member 17. Further, the contact shaft 8 is mounted so as to extend over the operating section Y and the contact chamber Z through the supporting hole 17h.

A movable contact 8e is provided at one end of the contact shaft 8 situating within the contact chamber Z. At the rear side of this movable contact 8e, an annular plate 9a is secured to the contact shaft 8, and there is provided a coil spring 9b for pressing the movable contact 8a to the stationary contact (described later) side between the plate 9a and the movable contact 8e. At the other end of the shaft situating on the side of the operating section Y, an annular plate 9c is secured to the contact shaft 8, and there is provided a return coil 9d between the plate 9c and the front bracket 20.

Further, a shift plate 7 is mounted on the rear end of the plunger 4. This shift plate 7 is an elongated plate extending in the upper and lower directions with a hole formed on the center side for mounting on the rear of the plunger 4 and a through-hole 7s on the upper portion corresponding to the contact shaft 8. This shift plate 7 is secured to the plunger 4 with an engaging ring 7t.

The DC motor section X, the contact chamber Z and the operating section Y are divided by partition plates 34, 35.

Also, the contact chamber Z is divided by a contact chamber wall 31 and a contact chamber cover 32. The contact chamber wall 31 is provided with a first stationary contact 10a and a second stationary contact 10b.

The first stationary contact 10a is connected to a battery through a terminal bolt 11.

The second stationary contact 10b is connected to the positive pole brushes through a lead wire and is also connected to the other end of the exciting coil 2a of the electromagnet 2.

In the state where the terminal bolt 11 is secured in potion by a nut ha, the first stationary contact 10a is also secured to the contact chamber wall 31 by the bolt head 11t.

33 is an O-ring and 70b is a packing.

A rear end 16e of the shaft 16 is rotatably supported on a rear bracket 40 through a bearing 60a, and a front end it of the output shaft 1 is supported on the tip 20t side of the front bracket 20 through a bearing 60e.

Provided on the front side of the output shaft 1 through an engaging ring 51 is a stopper 52. Also, a stopper 53 is provided on the tip of the pinion 3P. Between these stoppers 52 and 53, there is provided a return spring 54.

FIG. 6 shows a perspective view of the output shaft 1, FIG. 7(a) and (b) show a perspective view of the overrunning clutch 3, and FIG. 8 shows a perspective view of the plunger 4 and shift plate 7, respectively.

Next, the operation will be described.

When the ignition switch is turned ON and current flows to the exciting coil 2a of the electromagnet 2, the plunger 4 is attracted toward the exciting core 2c, the plate 5a pushes the coil spring 6, and the plate 5b presses the thrust spline 3A to push the overrunning clutch 3 out toward the ring gear 50. As a result, as the end surface 3Pe of the pinion 3P provided at the overrunning clutch 3 is brought into contact with the end surface 50e of the ring gear 50, the movement of the overrunning clutch 3 in the forward direction stops for a while. However, while the plate 5a provided on the inner circumferential side of the plunger 4 compresses the coil spring 6, the plunger 4 is further attracted and continues to move. The shift plate 7 also moves forward and contacts the plate 9c.

After this state, the plunger 4 is continuously attracted and the plate 9c secured to the contact shaft 8 is pushed by the shift plate 7 to cause the contact shaft 8 to move forward. As a result, when the movable contact 8e of the contact shaft 8 is brought into contact with the first and second stationary contacts 10a, 10b, electric power is supplied from a battery and the armature 12 begins to rotate.

The contact shaft 8 continuously moves until the plunger 4 is completely attracted and its front end 4t is brought into contact with the exciting core 2c. At this time, the coil spring 9b is compressed by the plate 9a and thus, the movable contact Be is pressed and kept in contact with the first and second stationary contacts 10a, 10b.

When the armature 12 begins to rotate, the rotational force is decelerated through the deceleration mechanism 18 and is transmitted to the output shaft 1, the overrunning clutch 3 that is spline connected to the output shaft 1, and further to the pinion 3P. Then, when the pinion 3P turns slowly and the crests and roots of the pinion 3P agree with those of the ring gear, the pinion 3P is pushed forward by the spring force (the elastic force) of the compressed coil spring 6 and completely engages with the ring gear 50. Thus, as a crankshaft connected to the ring gear 50 turns, the engine is started.

When the engine is started, the output shaft 1 is separated from the pinion 3P by the action of the overrunning clutch 3 and the pinion 3P runs idle. Then, when the power supply to the exciting coil 2a is stopped, the pinion 3P is disengaged from the ring gear 50 as the plunger 4 and the overrunning clutch 3 are returned to their original positions by the return coil springs 9d and 54.

Further, when the crests and roots of the pinion 3P agree with those of the ring gear 50, the end surface 3Pe of the pinion 3P is not brought into contact with the end surface 50e of the ring gear 50, but the pinion 3P engages with the ring gear without any problem.

As described above, according to the starter and the starter installation method according to the present invention, it is possible to reduce the manufacturing cost of the starter and fully secure the precision around the output shaft.

## Claims

1. A starter having an output shaft driven by an electric motor, comprising: overrunning clutch which are coaxially arranged on the output shaft, the exciting coil of the electromagnet being excited to attract the plunger for driving the motor, the overrunning clutch with a thrust spline which is spline-connected to the output shaft being moved toward a ring gear to cause a pinion provided on the overrunning clutch to engage with the ring gear for starting an engine; and bracket and a front bracket which form an enclosing member for the starter.

2. A starter according to claim 1, wherein one end surface of the electromagnet in the axial direction of the output shaft is brought into direct contact with either one of the center bracket or the front bracket, and the other end surface is secured to the other bracket through a cushioning member.

3. A starter according to claim 2, wherein an outer circumference on the end surface of the electromagnet directly contacting with the bracket is press-fitted to the bracket.

4. A starter according to claim 1, wherein the output shaft is integrally provided with a shaft section, and a flange section for receiving the rotational force of the motor through a deceleration mechanism.

5. A starter according to claim 2, wherein the output shaft is integrally provided with a shaft section, and a flange section for receiving the rotational force of the motor through a deceleration mechanism.

6. A starter according to claim 3, wherein the output shaft is integrally provided with a shaft section, and a flange section for receiving the rotational force of the motor through a deceleration mechanism.

7. A method of assembling a starter according to claim 4, comprising the steps of: section and the flange section, on the motor through the deceleration mechanism which is adapted to combine with the flange section; where the electromagnet is held in position between the front bracket and the center bracket; and direction by fastening a bolt so that the electromagnet can be secured between the front bracket and the center bracket.