JPH03141817A - Starter and assembling method thereof - Google Patents

Abstract

PURPOSE:To minimize an equivalent bending moment acting on a pinion clutch from a pinion at the time of cranking by amounting a cushion spring in front of the pinion and a second helical spline. CONSTITUTION:A spring bearing A is provided at a pinion 15 in front thereof, a spring bearing B is provided at a pinion shaft 12 in the rear of the spring bearing A and in front of a second helical spline 14, and a cushion spring 16 is interposed between the spring bearings A, B. With these means, the cushion spring 16 can be mounted in front of the pinion 15 and the second helical spline 14. Therefore, as the distance between first and second helical splines 13, 14 can be shortened, an equivalent bending moment acting from the pinion 15 to a pinion clutch 3 at the time of engine cranking can be reduced, and the load stress that acts on each part of the pinion shaft 12 and the pinion clutch 3 can reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a starter, and more particularly to a starter pinion engagement mechanism.

[Conventional technology]

A conventional starter, particularly a starter with a speed reduction mechanism, connects a motor shaft and a pinion shaft via a speed reduction mechanism and a pinion clutch (one-way clutch). Specifically, 1, for example, a reduction gear is formed on the outer periphery of the clutch outer, this is engaged with the armature gear of the motor shaft, and a pinion shaft is further inserted into the inner periphery of the clutch while being connected to the inner periphery of the clutch via a helical spline. I'm letting you do it.

The helical spline transmits the power of the motor to the pinion shaft and maintains the operation when the pinion shaft is shifted to the ring gear on the engine side.

Additionally, when the pinion and ring gear collide with each other at their corners (gear end faces), the above structure alone does not provide enough torque to cause the pinion to engage the ring gear.
Recently, as disclosed in Japanese Patent Application Laid-open No. 64-569669, in addition to the above-mentioned helical spline (first helical spline), the tip side of the pinion shaft (
The second helical spline (one end near the ring gear)
The pinion and pinion shaft are connected via a biting assisting spline.

In this prior art, in addition to engaging the pinion with the pinion shaft via the second helical spline, the pinion is urged in the axial direction with a cushion spring.

When the pinion and the pinion shaft are shifted toward the ring gear, if the corners of the pinion and ring gear collide, the pinion shaft will resist the force of the cushion spring while the pinion remains in contact with the corner of the ring gear. and move forward.

At this time, the pinion is displaced in the circumferential direction along the second helical spline due to relative movement with the pinion shaft. As a result, the pinion and the ring gear can be forcibly aligned and the pinion can be engaged with the ring gear.

[Problem to be solved by the invention]

By the way, in the second engagement method using a helical spline, a cushion spring that biases the pinion is arranged behind the pinion. Specifically, a spring stopper is fixedly arranged at a rear position of the pinion on the outer periphery of the pinion shaft, and a cushion spring is interposed between the spring stopper and the rear surface of the pinion.

However, according to this arrangement structure of the cushion spring, a large space is required for mounting the cushion spring behind the pinion and the second helical spline, so there are the following points to be improved.

This problem will be explained with reference to FIGS. 8 and 9.

Figures 8 and 9 show the second mechanism that functions as a biting assist mechanism.
A conventional example with a helical spline.

FIG. 3 is an explanatory diagram showing how force is applied during engine cranking.

In these figures, 40 is a pinion shaft, 41 is a pinion clutch with a reduction mechanism, 42 is a first helical spline, 43 is a pinion, 44 is a second helical spline, 45 is a spring stopper, 46 is a cushion spring,
50 is a ring gear, and 51 is a motor shaft.

When the cushion spring 46 is located behind the pinion 43 as described above, the first
The distance from the second helical spline 42 to the second helical spline 44 becomes longer.

Therefore, during engine cranking (when the pinion and ring gear mesh), the equivalent bending moment applied to the pinion clutch 41 becomes larger than that applied to the pinion 43, and the first
．． There was a strength problem in that excessive stress was applied to the shaft portion between the second helical splines 42 and 44 and various parts of the pinion clutch.

In addition, the above 1. Other factors that increase the axial length of the shaft portion between the second helical splines include the following.

That is, the thickness of the tooth bottom of the pinion 43 (the portion indicated by the symbol C in FIGS. 8 and 9) needs to be kept to a certain level in order to maintain strength. Therefore, the root C is the 8th
As shown in FIG. 9, when one end of the cushion spring 46 is fitted to the rear surface of the pinion, the thickness of the entire pinion must be increased accordingly to ensure the necessary thickness of the tooth bottom C.

Therefore, the length increase will also increase accordingly.

In addition, the conventional cushion spring installation has a different structure.

A step for fixing the spring receiver is placed on the pinion shaft at the first. It is formed in the shaft portion between the second helical splines 42 and 44.

Therefore, concentrated load stress is applied to this stepped portion during engine cranking.

The present invention has been made in view of the above points, and its purpose is to reduce the equivalent bending moment applied from the pinion to the pinion clutch during engine cranking, and to reduce the excessive stress applied to each part of the pinion shaft and pinion clutch. The objective is to provide a starter with excellent durability. A further object of the present invention is to provide a technology that can improve the ease of assembling this type of starter.

[Means to solve the problem]

The present invention takes the following measures to achieve the above object.

Hereinafter, in order to facilitate understanding of the content, the explanation will be given with reference to the numbers in the drawings of the embodiments.

The first means for solving the problem will be explained by referring to the reference numerals in FIG. 1. The pinion shaft 12 moves forward and backward relative to the ring gear 30 of the engine by a shift mechanism 23, and the reduction gear that transmits the power of the motor to the pinion shaft 12. 2.5 and a pinion clutch 3, a clutch inner 7 of the pinion clutch 3 is connected to the pinion shaft 12 via a first helical spline 13, and a second helical spline 14 is connected in front of the pinion clutch 3. In the starter to which the pinion 15 is connected via.

A spring receiver A is attached to the pinion 15 in front of the pinion, and a spring receiver B is attached to the pinion shaft 12 at a position n behind the spring receiver 8 and in front of the second helical spline 14. A cushion spring 16 is interposed between the receivers A and 3, and the cushion spring 16 is installed in front of the pinion 15 and the second helical spline 14. Stopper L9 that restricts the forward movement of
a, and by the function of this stopper 19a and the force of the cushion spring 16, the pinion 15 is fitted onto the outer periphery of the upper pinion shaft 2 while applying preload.

Further, the second problem-solving means has structural features applicable to the starter of the first problem-solving means,
It is designed to improve the ease of assembling the starter, rationalize the number of parts, and improve durability, and is constructed as follows.

That is, one problem-solving means has a pinion shaft 12 that moves forward and backward relative to a ring gear 30 of the engine by a shift mechanism 23, and one end of the pinion shaft 12 closer to the ring gear is configured to engage the ring gear 30. In a starter in which a pinion 15 is fitted via an auxiliary helical spline (corresponding to the second helical spline described in the first problem solving means) 14, the biting auxiliary helical spline 14 is as shown in FIG. It consists of a shaft spline 14a disposed on the outer circumference of the pinion shaft 12 as shown in FIG. 5, and a pinion spline 14b disposed on the inner circumference of the pinion as shown in FIG.
A guide spline 19 for guiding the shaft spline 14a toward the shaft spline 14a is disposed in front of the shaft spline 14a with a gap 27 therebetween.

Of these, the number of teeth on the pinion spline 14b is determined by the number of teeth on the spline groove 14 of the shaft spline 14a that is to be engaged with the pinion spline 14b.
The number of grooves in a' is divided by an integer (an integer of 2 or more).

The guide spline 19 has a tooth width W8 in the same direction that is wider than a tooth width W2 of the shaft spline 14a, and the number of grooves is an integer (an integer of 2 or more) relative to the number of grooves of the shaft spline 14a. ), and furthermore, immediately behind the shaft spline 14a on the circumference between the pinion shafts 12, there is a pinion spline 14.
When b passes through the shaft spline 14a and reaches this rear position, a spline release area S is formed in which the engagement between the pinion spline 14b and the shaft spline 14a is released.

A third problem-solving means relates to a method for assembling a starter based on the structure of the second problem-solving means.
When fitting the pinion spline 14b to the pinion shaft 12, insert the pinion spline 14b on the inner circumference of the pinion 15 from the groove 19' of the guide spline 19 to the shaft spline 1.
4a through the groove 14a' and once the spline engagement between the pinion 15 and the pinion shaft 12 is released, the pinion 15 is rotated on the pinion shaft 12 [see FIGS. 6(a) and 6(b)] ], This rotation causes the teeth of the pinion spline 14b to face the groove 14a' of the shaft spline 14a, of which the groove 19' of the guide spline 19 does not exist on the extension line of the groove 14a' of the shaft spline 14a.
See Figure (b)], this opposing shaft spline 14
The pinion spline 14b is passed backward again through the groove 14a' of the pinion spline 14a, and one end of the pinion spline 14b is locked to the one end 19a of the guide spline 19 [see FIG. 6(c)].

The fourth problem-solving means relates to the structure of a new nion shaft that is optimal for use in the starter of the first problem-solving means, and its gist is that the first helical spline 13 of the pinion shaft 12 The shaft diameter of the shaft portion near the second helical spline 13 is all made uniform. In other words, the first helical spline 13 and the second
The cushion spring receiver, which was conventionally present on the shaft portion between the helical splines 14, is designed to eliminate the difference in level.

[Effect]

According to the first problem solving means, the following effects are achieved.

That is, when the pinion shaft 12 moves forward toward the ring gear 30 of the engine under the force of the shift mechanism 23 and the pinion 15 collides with a corner of the ring gear 30, the cushion spring 16 first absorbs this impact.

The pinion shaft 12 is connected to the cushion spring L6.
Go further against the force of. At this time, pinion 15
is in contact with the corner of the ring gear 30, but due to the forward movement of the pinion shaft 12 and the presence of the second helical spline 14, the pinion 15 is in contact with the corner of the ring gear 30.
dislocates in the circumferential direction at the top.

Therefore, the pinion 15 reaches a matching position with respect to the ring gear 30, and at this time, the pushing force of the pinion shaft causes the pinion 15 to advance toward the ring gear 30 and engage.

In the present problem solving means, the cushion spring 16 of the pinion 15 can be arranged in front of the pinion 15 and the second helical spline 14 due to the arrangement structure of the spring receivers A and H.

Therefore, there is no need to secure a space for the cushion spring 16 behind the second helical spline 14 as in the conventional case.

Thereby, the positions of the pinion 15 and the second helical spline 14 can be moved as close as possible to the pinion clutch 3 (close to the first helical spline 13).

In turn, the first helical spline 13. By shortening the distance tllQ between the second helical splines 14, the axial length of the pinion shaft 12 can be kept to the necessary minimum.

As a result, the equivalent bending moment applied to the pinion clutch by the pinion 15 due to the ring gear engagement during engine cranking can be significantly reduced.

Furthermore, according to this problem-solving means, since there is no fitting groove for fitting one end of the cushion spring to the rear surface of the pinion as in the conventional case, the thickness of the pinion can be reduced by that amount. and.

As the wall thickness of the pinion can be made thinner, the distance can be further shortened.

Note that, according to the above structure, the first
．． There is no need to provide a step between the second helical splines 13 and 14 for fixing the cushion spring receiver (sleeve washer) as in the conventional case. The shaft diameter of the shaft portion between the second helical splines can be made uniform. The advantage of this uniformity will be described in the operation of the fourth problem-solving means.

The second problem solving means and the third problem solving means are the first problem solving means mentioned above.
The present invention relates to a structure and an assembly method for improving the assemblability of a starter used as a means for solving the problem. The details have been explained in the embodiment section using the drawings of FIGS. 4 to 6, so the explanation here will be omitted.

The fourth means of solving the problem is to make the shaft diameter of the shaft portion between the first helical spline 13 and the second helical spline ↓4 uniform in the pinion shaft 12, so that there is no step in this portion. .

By eliminating this stepped part, the first position when cranking the engine. It is possible to eliminate concentrated stress from being applied between the second helical splines 13 and 14, thereby increasing the strength of the pinion shaft.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIG. 1 is a sectional view of essential parts of a starter which is an embodiment of the present invention.
FIG. 2 is a partial sectional view showing the state of engagement between the pinion and the pinion shaft, and FIG. 3 is a sectional view showing the overall structure of the starter.

As shown in FIG. 3, the starter includes a motor section 25 and a magnetic switch 24. As shown in FIG.

1 is a motor shaft, and an armature gear 2 is formed at one end of the motor shaft.

Reference numeral 12 denotes a pinion shaft, which is disposed parallel to the motor shaft.A pinion clutch 3 is fitted onto this shaft 12 via an I-th helical spline 13, as shown in detail in FIG. , a pinion 15 is fitted via the second helical spline 14.

The angle o2 of the second helical spline 14 is larger than the angle 01 of the first helical spline 13 (0↓(+72), and these helical splines are It is twisted in the opposite direction (counter-rotation direction).

The pinion 15 is integrally formed with the sleeve 15' and is disposed in front of the pinion clutch 3. sleeve 1
5' extends in front of the pinion 15.

The pinion clutch 3 includes a clutch outer 4 with a reduction gear 5. It is composed of a roller 6, a clutch inner 7, etc. That is, the clutch inner 7 is spline-coupled to the shaft 2 via the first helical spline 13, and both outer peripheral ends thereof are supported by the housing 9 and the bearing retainer 10 via ball bearings 8a, 8b. Further, the clutch outer 4 is fitted onto the outer periphery of the clutch inner 7 via a roller 6, and a one-way clutch mechanism is connected to the outer periphery of the clutch inner 7, the roller 6, and a clutch profile 11 provided on the inner periphery of the clutch outer 4. Configure.

The gear 5 on the outer periphery of the clutch outer 4 meshes with the gear 2 of the motor shaft 1 to constitute a speed reduction mechanism.

Here, the mounting structure of the pinion 15 will be explained.

As shown in FIG. 2, the second helical spline 14 includes a shaft spline 14a provided on the outer periphery of the pinion shaft 12, and a pinion 15 (pinion sleeve 15').
) and a pinion spline 14b provided on the inner periphery of the pinion spline 14b.

When the pinion 15 is fitted, the pinion spline 14b meshes with the shaft spline 14a. Also,
A third helical spline (guide spline) 19 is disposed on the outer periphery of the pinion shaft 12 in front of the shaft spline 14a. As will be described later, the guide spline 19 has a function of guiding the pinion spline 14b toward the shaft spline 14a when the pinion is assembled, and also has a function as a stopper that restricts the forward movement of the pinion 15 after the pinion is installed.

A retaining ring 18 is installed in a circumferential groove 29 inside the tip of the pinion sleeve 15', and a spring cover A is configured by disposing a spring cover 17 on the retaining ring 18.

Further, on the pinion shaft 12, a spring receiver B is set behind the spring receiver A and in front of the second helical spline 14. This spring receiver B consists of one end of the guide spline 19.

A cushion spring 16 is interposed between the spring receivers A and B. The above installation depends on the structure of the cushion spring 1.
6 is a pinion 15 and a second helical spline 14
The pinion shaft 15 is positioned further forward than the pinion shaft 15 and applies an axial force between the pinion 15 and the pinion shaft 12. Further, in this state, the pinion spline 14b is locked to one end 19a of the guide spline 19. That is, this locking portion 19a functions as a stopper that restricts the movement of the pinion in the forward direction.

In this way, the pinion 15 is connected to the cushion spring 16
It is attached to the tip of the pinion shaft 12 while being given a preload.

Reference numeral 20 denotes a return spring, which is arranged on the pinion shaft 12 at the rear of the clutch 3. 21 is a pinion stopper, and 22 is a stopper clip.

The load of the pinion return spring 20 is set low relative to the cushion spring 16, but has sufficient load characteristics to allow the pinion shaft 12 to return after moving forward.

Here, the process of assembling the pinion 15 into the pinion shaft 12 will be explained using the drawings of FIGS. 4 to 6.

4 shows a partial front view and a partial sectional view of the pinion shaft 12, and FIG. 5 shows a partial vertical sectional view and a horizontal sectional view of the pinion 5.

As shown in FIG. 5, the number of teeth of the pinion spline 14b is half the number of grooves of the spline groove 14a (see FIG. 4) of the shaft spline 14a that meshes with the pinion spline 14b.
It's Toshide.

On the other hand, the guide spline 19, as shown in FIG.
The number of grooves is set to be one half of the number of grooves of the shaft spline 14a.

Furthermore, grooves 14a of the shaft splines 14a, on which grooves 19' of the guide splines 19 do not exist, are arranged every other groove on the extension line thereof. @WS of the groove 14b' of the pinion spline 14b is equal to the face width W of the guide spline 19.

Furthermore, a pinion spline 14 is located immediately behind the shaft spline 14a on the outer circumference of the pinion shaft 12.
When b passes through the shaft spline 14a and reaches this rear position, a spline release region S is formed in which the pinion spline 14b and the shaft spline b are released from their engagement.

When the pinion 15 is assembled into the pinion shaft 12, it is carried out in the following manner.

FIG. 6 shows the procedure. As shown in FIG.
' through the groove 14a' of the shaft spline 14a.

Then, push the pinion 15 so that the pinion spline 14b is completely pulled out to the position of the area S behind the shaft spline 14a (FIG. 6(b)). In this state, the pinion 15 is It is rotated in the circumferential direction from the position indicated by the solid line to the position indicated by the dashed line.

Due to this rotation, the teeth of the pinion spline 14b are opposed to the shaft spline groove 14a', of the shaft spline groove 148', where the guide spline groove 19' does not exist on the extension line thereof.

Then, the pinion spline 14b is returned through the opposing spline groove 148' [FIG. 6(C)]
, one end of the pinion spline 14b is engaged with the stopper 19a of the guide spline 19, and the installation process is completed.

Next, the operation of this embodiment will be explained.

When starting the engine, push out the pinion shaft 2 with the shift lever 23, and at the same time push out the motor generator 1.
- The torque is transmitted from the motor shaft 1 via the armature gear 2 to the clutch gear 5 of the clutch outer 4, from the first helical spline 13 of the clutch inner 7 via the roller 6 to the pinion shaft 12, and then to the second helical spline. 14 to the pinion 15. If the pinion 15 is initially in a compatible position with respect to the ring gear 30, the force of the shift lever 23 and the torque of the motor act, and the pinion L5 bites into the ring gear 30.

When the pinion 15 and the ring gear 30 are in contact with each other at their corner portions, the extrusion force and torque alone cannot be used.

No biting occurs.

The biting in this case will be explained with reference to FIG.

First, as shown in FIG. 7(A), when the pinion 15 comes into contact with the ring gear 30, a gap G initially exists between the spring receiver A and the tip of the pinion shaft 12. The pinion shaft 12 is in contact with the ring gear 30 and its forward movement is restricted, while the pinion shaft 12 is connected to the shift lever 2.
3, it moves further forward against the force of the cushion spring 16 [Fig. 7 (b)].

At this time, the gap G gradually disappears. Since the pinion shaft 12 moves by the distance m0, this movement causes the pinion 15 to move to the second helical spline 1.
4, it is dislocated in the circumferential direction by the angular difference between the second helical spline 4 and the first helical spline 13 [FIG. 7(c)].

Then, as shown in FIG. 7(d), when the pinion 15 reaches the matching position of the ring gear 30, the pinion 15 moves forward by the force of the shift lever and the force of the return spring 20, and is engaged.

According to this embodiment, the following effects are achieved.

■Since the cushion spring 16 is placed in front of the pinion 15 and the second helical spline 14, the pinion 15 and the upper part of the second helical spline are moved toward the clutch inner 7 side (the first helical spline 13 side). The distance 1tltQ between the first and second helical splines can be shortened.

Therefore, the load transmitted from the ring gear 30 of the pinion 15 during engine cranking is equivalent to +1111. f
moment can be minimized. Therefore, the mechanical stress applied to each part of the pinion shaft and pinion clutch is reduced, and the durability of the starter is improved.

2) Since the pinion 15 does not have a notch for fitting the cushion spring 6, the pinion can be made thinner.
For that reason, number 1. By further shortening the distance between the second helical splines, it is possible to enhance the effect (2) above.

(2) Since the guide spline (annular protrusion) 19 formed integrally with the pinion shaft 12 also serves as a stopper for the cushion spring receiver 8 and the pinion shaft 5, the number of parts can be reduced and assembly work can be streamlined.

■Furthermore, when the pinion 15 is assembled into the pinion shaft 12, it can be done by simply pushing the pinion 15 into the second helical spline 14 side via the guide spline 19, rotating it and returning it. Therefore, it is possible to easily assemble the starter.

■First helical spline 13 of pinion shaft 12
．． Since the axial diameter of the shaft portion between the second helical splines 14 is made uniform, the cross-sectional area of this shaft portion is increased, and problems such as concentrated load stress being applied to this shaft portion are eliminated, and the shaft Strength can be increased.

In the above embodiment, the spring receiver A of the cushion spring is assembled into the pinion using a separate part from the pinion 15, but it is also possible to mold it integrally with the pinion 5.

〔Effect of the invention〕

According to the carver's means of solving problems, 1. Since the distance gfl between the second helical splines can be significantly shortened compared to the conventional method, it is possible to reduce the equivalent bending moment applied from the pinion to the pinion clutch during engine cranking, and the load stress applied to each part of the pinion shaft and pinion clutch. can be reduced and the durability of the starter can be improved. Furthermore, the centrifugal force resistance and vibration resistance of the starter can be increased.

Also, the second. According to the third problem-solving means, it is possible to improve workability when assembling the pinion into the pinion shaft.

Furthermore, according to the fourth problem solving means, the first. It is possible to eliminate concentrated stress from being applied to the shaft portion between the second helical splines during engine cranking, and to further improve the durability of the starter.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of essential parts showing one embodiment of the present invention, Fig. 2
3 is a partial sectional view showing the pinion fitted to the pinion shaft, FIG. 3 is a sectional view showing the entire embodiment, and FIG. 4 is a front view and sectional view showing a part of the pinion shaft. 5 is a partial vertical sectional view and a partial horizontal sectional view of the pinion, FIG. 6 is an explanatory diagram showing a part of the assembly process, and FIG. 8 and 9 are schematic explanatory diagrams showing conventional examples of a starter with a speed reduction mechanism. 1...Motor shaft, 2.5...Reduction gear, 3.
...Pinion clutch, 4...Clutch outer, 7.
...Clutch inner, 12...Pinion shaft, 1
3... First helical spline, 14... Second helical spline (biting assisting spline), 14
a... Shaft spline, 14b... Pinion spline, 15... Pinion, 16... Cushion spring, 19... Helical spline for guide (1m-shaped protrusion). 19a...stopper, 23...shift lever 124
...Magnetic switch, 25...Motor, A,
B...Figure Figure 247 Gnetinox I/Chi 25 ・Motor 5 Figure 4 Figure 5 Figure 6 Figure 5 Figure Figure Figure 5

Claims (1)

[Claims] 1. A pinion shaft that moves forward and backward with respect to a ring gear of the engine by a shift mechanism, and a reduction gear and a pinion clutch that transmit power of a motor to the pinion shaft, and the pinion shaft has a A starter in which a clutch inner of the pinion clutch is connected via a first helical spline, and a pinion is connected forward of the pinion clutch via a second helical spline, the pinion having a spring receiver in front of the pinion. A, a spring receiver B is provided on the pinion shaft at a position rearward of the spring receiver A and in front of the second helical spline, and a cushion spring is interposed between the spring receivers A and B, The cushion spring is installed in front of the pinion and the second helical spline, and a stopper is provided on the outer periphery of the pinion shaft to restrict the forward movement of the pinion, and this stopper function and the cushion A starter characterized in that the pinion is fitted onto the outer periphery of a pinion shaft while being preloaded by the force of a spring. 2. The starter according to claim 1, wherein the pinion has a pinion sleeve integrally extended on its front surface, and the spring receiver A is incorporated inside the tip of the pinion sleeve. 3. In the first claim or the second claim, the pinion shaft is provided with an annular projection integral with the pinion shaft at a position behind the spring receiver A and in front of the second helical spline, In the starter, the front surface of this annular projection serves as a spring receiver B for receiving one end of the cushion spring, and the rear surface functions as the stopper. 4. It has a pinion shaft that moves forward and backward relative to the ring gear of the engine by a shift mechanism, and a pinion is fitted to one end of the pinion shaft closer to the ring gear via a helical spline that assists in biting into the ring gear. In the starter installed, the helical spline for biting assistance includes a shaft spline arranged on the outer periphery of the pinion shaft and a pinion spline arranged on the inner periphery of the pinion, and the pinion shaft has the pinion A guide spline for guiding the spline toward the shaft spline is disposed at a distance in front of the shaft spline. Among these, the number of teeth of the pinion spline is an integer (an integer of 2 or more) of the number of grooves of the spline of the shaft spline that is to be engaged with the pinion spline, and the guide spline is arranged in the circumferential direction of the teeth. Width W_1
is wider than the tooth width W_2 of the shaft spline, and the number of grooves is set to an integral number (an integer of 2 or more) of the number of grooves of the shaft spline, and further, the shaft spline on the outer periphery of the pinion shaft is Immediately behind the starter, a spline release area is formed to release the engagement between the pinion spline and the shaft spline when the pinion spline passes through the shaft spline and reaches this rear position. . 5. It has a pinion shaft that moves forward and backward relative to the ring gear of the engine by a shift mechanism, and a pinion is fitted to one end of the pinion shaft closer to the ring gear via a helical spline that assists in biting into the ring gear. In the starter installed, the helical spline for biting assistance includes a shaft spline arranged on the outer periphery of the pinion shaft and a pinion spline arranged on the inner periphery of the pinion, and the pinion shaft has the pinion A guide spline for guiding the spline toward the shaft spline is disposed at a distance in front of the shaft spline, and the number of teeth of the pinion spline is set to the spline of the shaft spline to be engaged with the guide spline. The guide spline has a width W_1 in the circumferential direction of its teeth.
is wider than the width W_2 of the teeth of the shaft spline, the number of grooves is one integer (an integer greater than or equal to 2) than the number of grooves of the shaft spline, and the pinion is mounted on the pinion shaft. In this case, the pinion spline is passed through the shaft spline from the guide spline to once release the spline engagement between the pinion and the pinion shaft, and then the pinion is rotated on the pinion shaft; This rotation causes the teeth of the pinion spline to face the groove of the shaft spline on which the groove of the guide spline does not exist on the extension line of the shaft spline, and the pinion spline is placed in the groove of the opposing shaft spline. A method for assembling a starter, comprising passing the pinion spline backward again to lock one end of the pinion spline to one end of the guide spline. 6. A pinion shaft that moves forward and backward relative to the ring gear of the engine by a shift mechanism. A pinion clutch is connected to the outer periphery of the pinion shaft via a first helical spline, and a second
A starter in which a pinion is fitted through a helical spline, wherein the shaft portion of the pinion shaft between the first helical spline and the second helical spline has a uniform shaft diameter. pinion shaft.