JP2001207941A - Recoil starter mounting structure - Google Patents

Abstract

(57) [Summary] An object of the present invention is to provide a mounting structure for a recoil starter capable of suppressing a run-out during rotation of a pulley boss and reducing costs. A pulley connecting portion formed by fitting a low turbos portion 5 constituting an ACG 3 to a tapered portion 2 of a crankshaft 1 so as to be integrally rotatable with the crankshaft 1 and extending beyond the crankshaft 1 at one axial end thereof. Spline grooves 2 on the inner peripheral surface of
Form 3 The pulley boss 7 of the recoil starter 10 has a small-diameter portion 41 at one axial end and a spline projection 42 formed on the outer periphery thereof. And spline join. After that, when the pulley boss 7 is screwed to the shaft end of the crankshaft 1 with the bolt 6, the rotation direction of the pulley boss 7 can be positioned only by spline connection, and can be mounted with a high degree of precision so that there is little run-out during rotation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art It is known to mount a recoil starter for manually starting an engine on a crankshaft in conjunction with an ACG, for example, see Japanese Patent No. 2646230.
No. 5-43267 and No. 6-23738. In each of these, a pulley constituting a recoil starter is fixed to a shaft end of a crankshaft provided with ACG with a nut. However, in the case of a type in which the end of the crankshaft has a high temperature, such as a four-cycle engine, a special mounting structure using bolts is required to avoid a decrease in mounting accuracy due to thermal expansion.

FIG. 5 shows a conventional example of a pulley mounting structure of a recoil starter using such bolting, and FIG. 6 shows an axial section of the pulley boss portion (corresponding to line 6-6 in FIG. 7). FIG. 7 is a left side view of the pulley boss in FIG. As shown in FIG. 5, a low turbos portion 5 provided at the center of a rotor 4 constituting the ACG 3 is fitted to a tapered portion 2 formed at the shaft end of the crankshaft 1 in a tapered hole 5a. ing.

[0004] The tip side of the low turbos section 5 is the crankshaft 1.
An extended portion 5b that extends further from the shaft end of
A shaft hole 5c leading to the tapered hole 5a is formed on the shaft center side, and a two-sided width groove 5d is formed at the front end opening. A tip of a pulley boss 7 attached to a shaft end of the tapered portion 2 of the crankshaft 1 from the axial direction with a bolt 6 is fitted to and joined to the tip of the extension 5b. A pulley 8 is integrated with the pulley boss 7 and is manually rotated by a main body of a recoil starter 10 disposed on an axial extension of the crankshaft 1.

As is apparent from FIGS. 6 and 7, the pulley boss 7 is generally circular when viewed from the axial direction, but has a pair of cutout surfaces 7a parallel to the opposite portions of the cylinder at the tip end. A so-called two-sided width projecting portion 7b in a cut-out state is formed, and the distal end side is further a small diameter portion 7c. The two-sided width projection 7b is formed so as to be fittable with the two-sided width groove 5d of the rotor boss part 5, and the small diameter part 7c is fittable into the shaft hole 5c. A through hole 7d for the bolt 6 is formed through the shaft center of the pulley boss portion 7.

Therefore, the bolt 6 is passed through the through-hole 7d with the two-face width projection 7b fitted into the two-face width groove 5d and the small-diameter part 7c fitted into the shaft hole 5c. If the pulley boss portion is fastened to the crankshaft 1, the pulley boss portion 7 and the rotor boss portion 5 can be connected in the rotation direction by fitting the two-face width projection 7b and the two-face width groove 5d. . The portion indicated by the grid line in FIG. 7 is a pressure receiving portion 7e, which is brought into contact with the distal end surface of the extension portion 5b of the rotor boss portion 5 by the axial force when the bolt 6 is fastened. Reference numeral 9 in FIG. 5 denotes an escape space during thermal expansion.

[0007]

In the case of the conventional structure shown in FIGS. 5 to 7, the rotation of the pulley boss 7 is rotated to the rotor boss 5 by the fitting of the two-face width projection 7b and the two-face width groove 5d. Therefore, it is necessary to suppress the runout of the pulley boss 7 in the rotation direction. As a result, high fitting accuracy is required. Therefore, both the two-face width projection 7b and the two-face width groove 5d are machined. Need to be formed. The positioning in the direction parallel to the notch surface 7a is performed by the small-diameter portion 7c and the shaft hole 5c, and the positioning in the direction perpendicular to the notch surface 7a is performed by the two-sided projection 7b and the two-sided groove 5d. In order to minimize the run-out of the boss 7, the positional accuracy by a plurality of processes must be strictly controlled, and as a result, the processing cost and the management cost increase. Then, this invention aims at solving such a problem.

[0008]

According to the present invention, there is provided a recoil starter mounting structure according to the present invention, in which a rotor turbos portion of an ACG is fitted onto a tapered portion formed at one end of a crankshaft to be integrated. While being rotatable, the pulley boss portion of the recoil starter is coaxially arranged with respect to the shaft end of the crankshaft, bolted from the axial direction, and integrally rotatable with the low turbos portion,
The coupling between the rotor boss portion and the pulley boss portion is spline coupling.

[0009]

According to the present invention, since the rotor boss portion and the pulley boss portion are spline-coupled, the rotor boss portion is fitted onto the tapered portion of the crankshaft so as to be integrally rotatable, and is further fitted to a part of the rotor boss portion. When the pulley boss portion is coaxially arranged and spline-coupled, and then the pulley boss portion is fastened to the shaft end of the crankshaft by a bolt from the axial direction of the crankshaft, the pulley boss portion is moved relative to the crankshaft and the rotor boss portion. Combine so that they can rotate together.

[0010] For this reason, the rotational runout of the pulley boss depends on the positioning accuracy of the spline connection, and the processing and management for achieving this accuracy are performed by the conventional two-sided projection and the two-sided width groove. It is much easier than the fitting structure of Therefore, even in a process that does not require strict accuracy control as in the related art, the run-out of the pulley boss can be minimized, and as a result, the processing cost and the management cost can be suppressed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to the drawings. 1 is a sectional view similar to FIG. 5 showing a recoil starter portion, FIG. 2 is a partially cutaway view of an engine to which the present invention is applied, and FIG. 3 is an axial sectional view of a pulley boss portion shown in FIG. FIG. 4 is a cross-sectional view taken along line -3, and FIG. 4 is a diagram showing a left side surface of the pulley boss portion in FIG. Note that the common reference numerals are used for the common function portions with the previous conventional example, and the description thereof will be omitted or simplified.

First, in FIG. 2, the engine to which the present embodiment is applied is for an off-road vehicle, and the engine 4 is arranged vertically with the rotation center axis of the crankshaft 1 disposed in the front-rear direction of the vehicle body. An ACG 3 is provided on a tapered portion 2 formed on one side of a crankshaft 1, and a pulley 8 of a recoil starter 10 is attached to a shaft end of the cycle engine.

On the other hand, an automatic centrifugal starting clutch 11 is provided at the other end of the crankshaft 1, through which the rotation of the crankshaft 1 is transmitted to the transmission 12, and the drive shaft 14 is moved forward and backward from the output shaft 13. , 15 are output. In the figure, reference numeral 16 denotes a front and rear split crankcase, 17 denotes a rear cover, and 18 denotes a front cover.

Next, the mounting structure of the recoil starter 10 will be described in detail with reference to FIG. 1, FIG. 3 and FIG. A tapered hole 20 formed in the low turbos portion 5 is fitted on the tapered portion 2 of the crankshaft 1, and the rotation direction is changed to a key 21.
Are connected by One end of the rotor boss 5 in the axial direction forms a pulley connecting portion 22 extending further in the axial direction than the tip of the tapered portion 2, and a spline groove 23 is formed on the inner peripheral surface thereof. Tip 24 of pulley coupling section 22
Is in contact with the pulley boss 7 in the axial direction of the crankshaft 1.

A flange 25 is formed on the other end of the rotor boss 5 so as to extend radially outward, and the rotor 4 of the ACG 3 is integrally connected to the rotor 4 by pins 26. A stator coil 27 of the ACG 3 is accommodated in a space between the rotor 4 and the pulley coupling portion 22, and is attached to a support wall 29 integrally formed with a part of the rear cover 17 by a bolt 28.

The pulley boss 7 has a through hole 30 formed in the center of the shaft, and is attached to the shaft end of the crankshaft 1 from the axial direction by a bolt 6 passing therethrough. The center portion of a substantially cup-shaped pulley 8 which is a part of the recoil starter 10 is welded and integrated with the outer peripheral portion of the pulley boss 7. The outer peripheral surface of the pulley boss 7 is polished and finished, and an oil seal 31 is fitted between the outer peripheral surface and the opposing support wall 29 to seal between the outside and the inside of the engine. I have.

The reel 32 constituting the main body of the recoil starter 10 is rotatably mounted on a boss 34a integral with the recoil starter cover 34 by bolts 33, and the recoil rope 35 wound around the reel groove.
One end of the pulley 8 is rotated by being pulled by a starter knob 36 attached thereto, and the one-way clutch 37 integrated with the reel 32 is engaged with the flange portion 38 of the pulley 8 to transmit the rotation to the pulley 8.

When the rotation of the reel 32 is transmitted to the pulley 8, the rotor boss 5 which is spline-coupled with the pulley boss 7 rotates integrally. As a result, the crankshaft 1 is rotated via the rotor boss 5. By integrally rotating, the engine is manually started.

As shown in FIGS. 3 and 4, the pulley boss 7 has a step portion 40 formed at an intermediate portion in the axial direction, and the rotor boss portion 5 forms a small-diameter portion 41 at the boundary, and a spline around the portion. The projection 42 is formed, and can be spline-coupled to the spline groove 23 formed on the inner peripheral surface of the rotor boss 5. Note that the step portion 40 is a portion where the tip 24 of the pulley coupling portion 22 of the rotor boss portion 5 abuts on the entire peripheral surface of the step portion, and forms a pressure receiving portion of the entire periphery as shown by a grid line in FIG. I have.

The pulley boss 7 is formed by an appropriate method such as casting or forging using an appropriate metal material, and then the spline projection 42 is formed by rolling or shaper processing. Also, a sealing surface 43 (FIG. 3) which is an outer peripheral surface of the large diameter portion.
Is polished and finished as described above. On the other hand, the rotor boss part 5 is similarly formed by an appropriate method such as casting or forging, and thereafter, the spline groove 23 of the pulley coupling part 22 is formed by broaching.

Next, the operation of the present embodiment will be described. As shown in FIG. 1, the small diameter portion 41 of the pulley 7 arranged coaxially is fitted to the rotor boss portion 5 fitted on the tapered portion 2 inside the pulley coupling portion 22. The spline groove 23 of the pulley coupling portion 22 and the spline projection 42 of the small diameter portion 41 are spline-coupled. In this state, the pulley 7 is screwed from the axial direction of the crankshaft 1 to the shaft end of the crankshaft 1 with the bolt 6.

As a result, the step 40 of the pulley boss 7 is
Abuts on the tip end 24 of the pulley coupling portion 22 in the rotor boss portion 5 in the axial direction of the crankshaft 1 and exerts the axial force of the bolt 6, so that the rotor boss portion 5 is axially positioned on the tapered portion 2 by taper coupling. The pulley boss 7 is reliably positioned in the axial direction with the end surface of the step portion 40 in contact with the end surface of the tip 24 all around.

In the rotational direction, the pulley connecting portion 22
Are positioned by spline connection with Accordingly, since the rotation direction is spline-coupled and the axial direction is received by the pressure receiving surface of the entire circumference, the run-out during rotation of the pulley boss 7 can be significantly suppressed.

Moreover, the positioning accuracy depends on the accuracy of the spline connection, but the accuracy management is sufficient only at the spline connection portion. Therefore, there is no need for positioning in a plurality of processing portions having different contents as in the case of forming the fitting structure portion with the two-face width projection and the same groove in the conventional example, and they are simply formed at equal intervals in the circumferential direction. Since the processing accuracy of the uniform spline grooves 23 and the spline projections 42 may be controlled, the processing can be remarkably facilitated and the precision control can be eased. As a result, the processing cost and the management cost can be significantly reduced.

It should be noted that the present invention is not limited to the above-described embodiment, and various applications and modifications are possible. For example, the spline connection between the pulley boss 7 and the rotor boss 5 is reversed inside and outside, and the pulley boss 7 May be fitted onto the pulley coupling portion 22 of the rotor boss 5, and a spline groove may be formed on the pulley boss 7 side, and a spline projection may be formed on the pulley coupling 22 of the rotor boss 5.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a recoil starter mounting structure according to an embodiment.

FIG. 2 is a partially cutaway view of the engine to which the embodiment is applied.

FIG. 3 is a sectional view of the pulley boss corresponding to the line 3-3 in FIG. 4;

FIG. 4 is a sectional view of a pulley boss.

FIG. 5 is a diagram corresponding to FIG. 1 in a conventional example.

FIG. 6 is a diagram corresponding to FIG. 3;

FIG. 7 is a diagram corresponding to FIG. 4;

[Explanation of symbols]

1: crankshaft, 2: tapered portion, 3: ACG, 4: rotor, 5: low turbos portion, 7: pulley boss portion, 8:
Pulley, 10: Recoil starter, 22: Pulley connection part, 23: Spline groove, 42: Spline projection small diameter part

Claims (1)

[Claims] 1. A low turbos portion of an ACG is fitted on a tapered portion formed on one end side of a crankshaft so as to be integrally rotatable, and a pulley boss of a recoil starter is attached to a shaft end of the crankshaft. In the mounting structure of the recoil starter, which is coaxially arranged and bolted from the axial direction, and integrally rotatably connected to the rotor boss, the connection between the rotor boss and the pulley boss is spline-connected. Mounting structure for recoil starter.