Pinion Starter Gearing Having Corrected Gear Geometry

Abstract

A pinion starter drive for an internal combustion engine is provided. The pinion starter drive includes a drive pinion and a starter gear. At least one tooth of the drive pinion has a drive actual profile, and at least one tooth of the starter gear has a starter actual profile. A sum of at least one discrete value of a deviation of the drive actual profile from a drive target profile in the drive pinion tooth root region and at least one discrete value of a deviation of the starter actual profile from a starter target profile in the starter gear tooth tip region is less than 0. A method of manufacture of a pinion starter drive includes selecting a drive pinion and a starter gear from a plurality of gears having a deviation sum less than zero.

Claims

1. A pinion starter drive for an internal combustion engine in a motor vehicle, comprising a drive pinion rotatable about a drive axis; and a starter gear rotatable about a starter axis, wherein the drive pinion and the starter gear are gearwheels having teeth configured to mesh with one another, at least one tooth of the drive pinion has an actual drive profile in a drive reference plane orthogonal to the drive axis, at least one tooth of the starter gear has an actual starter profile in a starter reference plane oriented orthogonal to the starter axis, a radially outer half of the each of the actual drive profile and the actual starter profile is a tooth tip region, a radially inner half of the each of the actual drive profile and the actual starter profile is a tooth base region, a target drive profile for the at least one tooth of the drive pinion defines a drive reference plane, a target starter profile for the at least one tooth of the starter gear defines a starter reference plane, and a sum S of at least one discrete value of a deviation F.sub.driveF of the actual drive profile from the target drive profile in the tooth base region of the drive pinion and at least one discrete value of a deviation F.sub.starterK of the actual starter profile from the target starter profile in the tooth tip region of the starter gear is less than 0, wherein deviations in a direction toward an interior of the at least one tooth of the drive pinion and toward an interior the at least one tooth of the starter gear have a negative sign.

2. The pinion starter drive as claimed in claim 1, wherein at least one of the actual drive profile and the actual starter profile differ from the respective target drive profile and target starter profile in at least in partial sections of the respective profiles by more than 2 m and less than 60 m.

3. The pinion starter drive as claimed in claim 2, wherein deviation F.sub.driveF of the actual drive profile and the deviation F.sub.starterK of the actual starter profile each comprise an arithmetic mean value of at least two discrete deviations of the respective actual profiles from the respective target profiles.

4. The pinion starter drive as claimed in claim 3, wherein an absolute value of at least one of the discrete deviations F.sub.driveF of the actual drive profile is greater than 2 m and less than 60 m.

5. The pinion starter drive as claimed in claim 3, wherein an absolute value of at least one of the discrete deviations F.sub.driveF of the actual drive profile is greater than or equal to 5 m and less than 25 m.

6. The pinion starter drive as claimed in claim 5, wherein the absolute value of the arithmetic mean value of the at least two discrete deviations F.sub.driveF of the actual drive profile is essentially 20 m.

7. The pinion starter drive as claimed in claim 3, wherein an absolute value of at least one of the discrete deviations F.sub.starterK of the actual starter profile is greater than 2 m and less than 60 m.

8. The pinion starter drive as claimed in claim 7, wherein an absolute value of at least one of the discrete deviations F.sub.starterK of the actual starter profile is greater than or equal to 5 m and less than 25 m.

9. The pinion starter drive as claimed in claim 8, wherein the absolute value of the arithmetic mean value of the at least two discrete deviations F.sub.starterK of the actual starter profile is essentially 20 m.

10. The pinion starter having a starter pinion drive as claimed in claim 1, further comprising: an electric motor configured to drive the drive pinion; and a shifting device configured to shift the drive pinion along the drive axis to place the drive pinion into engagement with the starter gear and to disengage the drive pinion from the starter gear.

11. A method for manufacturing a pinion starter drive, comprising the acts of: providing a plurality of drive pinions rotatable about a drive axis and a plurality of starter gears rotatable about a starter axis, wherein the drive pinion and the starter gear are gearwheels having teeth configured to mesh with one another, at least one tooth of the drive pinion has an actual drive profile in a drive reference plane orthogonal to the drive axis, at least one tooth of the starter gear has an actual starter profile in a starter reference plane oriented orthogonal to the starter axis, a radially outer half of the each of the actual drive profile and the actual starter profile is a tooth tip region, a radially inner half of the each of the actual drive profile and the actual starter profile is a tooth base region, a target drive profile for the at least one tooth of the drive pinion defines a drive reference plane, and a target starter profile for the at least one tooth of the starter gear defines a starter reference plane; and matching one of the plurality of drive pinions and one of the plurality of starter gears to form the pinion starter drive, wherein a sum S of at least one discrete value of a deviation F.sub.driveF of the actual drive profile from the target drive profile in the tooth base region of the drive pinion and at least one discrete value of a deviation F.sub.starterK of the actual starter profile from the target starter profile in the tooth tip region of the starter gear is less than 0, wherein deviations in a direction toward an interior of the at least one tooth of the drive pinion and toward an interior the at least one tooth of the starter gear have a negative sign.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 illustrates target and actual profiles in accordance with an embodiment of the present invention.

[0034] FIG. 2 illustrates a partial perspective view of a pinion starter drive in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0035] FIG. 1 illustrates different target/actual profiles in a reference plane. The target drive profile 1 can clearly be generated by a thread structure. In contrast with this, a first actual drive profile 2 and a second actual drive profile 3 are illustrated.

[0036] The drive reference plane, an orthogonal plane with respect to the drive axis (not illustrated), is the plane of the illustration in which these profiles are represented. In the vertical direction 16 of the teeth, that is to say in the radially outward direction with respect to the drive axis (not illustrated) of the drive pinion, a tooth of the drive pinion, and therefore the illustrated profiles, can be divided into a tooth tip region 7 (radially outer part) and into a tooth base region 8 (radially inner part).

[0037] The tooth, illustrated here only partially by the profiles in the drive reference plane, of the drive pinion extends in the direction of the material side 5, which is shown by way of example on the target profile 1. A deviation 9 (F.sub.driveF) of the first actual drive profile 2 in the tooth base region 8 has a negative sign in the direction 4, that is to say toward the interior of the tooth. A deviation 10 (F.sub.driveK) of the first actual drive profile 2 in the tooth tip region 7 has a positive sign counter to the direction 4, that is to say figuratively an addition of material to the target profile.

[0038] This logic applies correspondingly to the starter gear, deviation in the tooth tip region; F.sub.starterK, deviation in the tooth base region; F.sub.starterF, while a deviation toward the interior of the tooth also has a negative sign here. The lines 6 which are shown indicate the tolerance range within which the actual drive profiles 2, 3 have to lie.

[0039] If the starting point is an actual starter profile (not illustrated) which does not correspond completely to the target starter profile (not illustrated), for which F.sub.starterF=F.sub.starterK=0 is therefore also true, the condition S<0 would be met with the illustrated first actual drive profile 2, and the condition would not be met with the second actual drive profile 3.

[0040] FIG. 2 illustrates a partially perspective view of a pinion starter drive with a target profile 1 of the drive pinion 15. The teeth of the drive pinion 15 have a tooth tip region 7. The drive pinion 15 meshes with the starter gear 16 in order to transmit movement. In this context, the drive pinion 15 is mounted so as to be rotatable about the drive axis 22, and the starter gear 16 is mounted so as to be rotatable about the starter axis 23.

[0041] The tooth base region, as an active part of the toothing arrangement, is obtained from the entire tooth height 17 minus the tip play 18 and the tooth tip region 7. The illustrated gearwheels 15, 16 have a tooth width 20.

[0042] The illustrated toothing arrangement has a pitch 22, and the drive pinion has a tip diameter 19 which bounds the teeth radially outward. The pitch diameter 21 has, as presented, decisive significance for the generation of the target drive profile 1.

[0043] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.