JPH06182470A - Method for manufacture of metal plate made starter rim gear and starter rim gear manufactured by said method - Google Patents

Abstract

PURPOSE: To make it possible to manufacture a starter rim gear made of a sheet metal based on a Grob method in a manner as to obviate the occurrence of the defect that the wall thickness is excessively small. CONSTITUTION: The wall thickness 116 of the peripheral wall 112 of a working blank 100 is changed by cold plastic deformation based on the Grob method by which the distance 16 between the dedendum circle 14 of the tooth space base of a manufactured external tooth row 13 and the shortest point of the inside surface 15 of the manufactured peripheral wall 12 is made smaller than the thickness 116 of the peripheral wall 12 of the working blank 100 and the dedendum circle 14 of the external tooth row 13 is extended at all times within the manufactured peripheral wall 12 having the external tooth row 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a sheet metal starter / rim gear and a starter / rim gear manufactured by the method.

[0002]

2. Description of the Related Art Despite the fact that the glove method is well known in publications and in practice, a glove method for producing an external dentition by subjecting a relatively thin hollow processed material to cold plastic deformation First, I'll briefly explain it and, just in case, avoid unreasonable misunderstandings.

In the glove method, an outer cross-sectional shape and an inner cross-sectional shape are manufactured at the same time by cold plastic deformation working, and the cross-sectional shape can have different forming profiles. Due to this plastic deformation, the tubular portion of the work material is fitted onto the mandrel corresponding to the inner cross-sectional shape. The work material is fed in this state, and in the case of the work feed, the work material is shifted along the work material axis and rotated about the work material axis. During this process feed, the work material is processed from the outside by a ring-shaped forming roll, at which time each forming roll performs shocking individual rolling operations in a quick order in harmony with the forming pitch and the processing material feed. Be done. This individual rolling operation is performed in the same direction and mainly in the direction corresponding to the longitudinal direction of the forming profile. The individual rolling operations, which are carried out successively one after the other by the same roll, then proceed along a spiral zone, which is defined by the feed of the workpiece. The individual rolling operations, which are successively carried out in the same tooth space in the longitudinal direction of the forming profile, are carried out while partially overlapping with respect to the action of the roll on the workpiece. In the above-described method of performing cold plastic deformation on the forming mandrel, the material is fed into the forming groove of the mandrel mainly in the radial direction along with a relatively small work piece segment in each individual rolling operation. Methods relating to such relatively thick workpieces are disclosed in Swiss Patent No. 579427, French Patent No. 7538539 and German Patent Publication No. 2549230.

It is well known that internal combustion engine starters are often referred to as starters in Germany and many other countries.

In an internal combustion engine of an automobile such as a passenger car, an electric rim gear cranking starter is mainly used. This starter is provided with an electric motor that is powered by a vehicle-mounted battery, and the electric motor drives a pinion for starting. The pinion meshes with a starter / rim gear mounted on the electric motor during the starting operation.

This presupposes that the starter-rim gear has the correct rotating wheel tooth ratio.

Unlike other sheet metal toothed mechanisms such as toothed belt pulleys, clutch plate carriers and spline tubes used in the automotive field, the tooth rows of starter rim gears are purely geometric. A tooth wheel having the shape of a rotating wheel, that is, a pure gear having a relatively strong tooth row (when measured in the radial direction) and a narrow tooth row width (when measured in the axial direction). Is one that meshes with another pure gear (pinion).

A method of making a starter rim gear with tooth rows having a purely geometric rotating wheel shape has been proposed, for example, in US Pat. No. 4,796,345.

However, said US Pat. No. 4,796,634.
The starter rim gear manufactured as described above by the method disclosed in No. 5 may unfortunately often have a tooth surface thickness that is significantly insufficient for certain applications. It has the drawback of being numerous.

Molded mandrels, that is to say mandrels with a clearly engraved tooth profile, are inherently susceptible to damage, have a relatively short service life, and are expensive to manufacture.

[0011]

The object of the present invention is, in particular, that which often appears in the prior art,
It is to manufacture sheet metal starter / rim gears based on the globe method so as not to cause the drawback of having an excessively small wall thickness.

[0012]

[Means for Solving the Problems] A manufacturing means of the present invention for solving the above problems is to manufacture a sheet metal starter / rim gear having an external tooth row having a purely geometric rotating wheel shape. In, in the peripheral wall of the sheet metal material having a wheel flange extending in the radial direction from the outer periphery toward the machining material axis line, which is integrally coupled with a peripheral wall extending in a cylindrical shape in parallel and coaxially with the machining material axis line, In the manufacturing method of the sheet metal starter / rim gear, which is a type that forms the external tooth row with a pure geometric rotating wheel shape by performing cold plastic deformation processing based on the globe method, the wall thickness of the peripheral wall of the processing material Is changed by cold plastic deformation processing based on the glove method, and the distance between the root circle of the tooth groove base of the manufactured outer tooth row and the shortest point of the inner surface of the manufactured peripheral wall is defined as the wall thickness of the peripheral wall of the processed material. Less than The Kunar so, and the dedendum circle of the external tooth row lies in to allow Zaisa always extend within the fabrication already peripheral wall having an external toothing.

It is advantageous to carry out cold plastic deformation of the peripheral wall of the work material for forming the peripheral wall of the rim gear on the mandrel.

It is particularly advantageous for the mandrel to have a cylindrical or slightly corrugated cross-section.

The present invention further comprises a wheel flange extending radially from the outer periphery toward the workpiece axis, the radial outermost portion of the wheel flange being parallel to the workpiece axis. A peripheral wall as a gear rim extending coaxially in a tubular shape and subjected to cold plastic deformation processing based on the globe method is integrally formed, and the peripheral wall has a steel thin plate subjected to cold plastic deformation processing. The invention relates to a sheet metal starter / rim gear manufactured by the above method, in which an external tooth row having a purely geometric rotating wheel shape is formed. The root circle of the row lies at the point which always extends inside the prefabricated peripheral wall with the outer row of teeth.

[0016]

According to the manufacturing method of the present invention, it is confirmed that the starter / rim gear can be manufactured in a form similar to the case of rolling into a solid material (in short, the case of rolling an external tooth row into a solid work material). Was done. In this case, it is no longer necessary to fit the sheet metal blank onto the forming mandrel, that is to say the hollow sheet metal part. Looking only at this point, it can be seen that the manufacturing is remarkably simple and the material can be saved significantly. This is because now all the means for making the formed mandrel, and in part, those that require rigorous experimental processes, are no longer necessary. The high cost of such shaped mandrels, for example shaped toothed mandrels, cannot only be one-time, but rather, such shaped mandrels cannot be expected to have long-term durability by nature, so that the It will be expensed.

In contrast to this, the present invention makes it possible to use a low-cost and durable mandrel of cylindrical cross section or slightly corrugated cross section.

In the present invention, as in the case of the forming part rolled into a solid material, it is possible to employ a steel work material which is easily subjected to surface hardening treatment.

Therefore, in the present invention, it is possible to use a steel thin plate which can be sufficiently cold plastically deformed and which can be surface-treated (by induction hardening) after plastic deformation as a processing material. The optimization in this case can be obtained by a simple experiment as is conventionally commonly used.

For example, the following process parameters are suitable: (a) It has been found that wheel flanges with a sheet metal thickness of the order of about 3 mm can be used in practice.

(B) It is of course advantageous that the sheet metal thickness of the peripheral wall of the processed material is a multiple of the sheet metal thickness of the wheel flange, for example, at least twice.

(C) Good results are obtained with a coefficient of about 2 to 2.5.

(D) The number of rotations of the rolling head is 1200 to 1
Optimally 400 rpm.

(E) Rolling is carried out by using two rolling heads at the above-mentioned number of rolling head revolutions, and each rolling head has one single rib roll. 3 to 6 mm for axial feed per revolution of the processed material when
If so, a beautifully formed dentition can be obtained. In the case of a roll having a plurality of ribs (for example, in the case of a roll having two or three ribs), the working density is high, and the axial feed can be correspondingly increased.
This also applies if two or more rolls are arranged on each rolling head and the number of revolutions is maintained accordingly.

The sheet metal starter / rim gear manufactured by the manufacturing method of the present invention has an advantage that, in addition to the above-mentioned economical advantage, a reliable reproducibility at the time of manufacturing is obtained.

Further, in addition to the advantage that high accuracy can be obtained with a small cost, the advantage that the service life is extended is obtained.

Not only that, but the thickness of the tooth flank area is significantly larger than that of the case where it is manufactured on the molded toothed mandrel, so that there is an advantage that load resistance is also improved.

In the case of high-quality materials, remarkably high elastic resilience occurs when rolling on a molded toothed mandrel.
This is because the material is shock-formed between the hard forming mandrel and the hard roll. In the present invention, no elastic mandrel is required anymore, so that the elastic resilience is significantly reduced. As a result, it is possible to operate with significantly increased material feed. Comparison with the relationship when rolling to solid material is only partially possible. This is because, in the present invention, the workpiece may be considered generally or at least partially hollow.

The sheet metal starter rim gears produced according to the preferred embodiment of the method of the invention can meet all the highest requirements.

[0030]

Embodiments of the present invention will now be described in detail with reference to the drawings.

The manufactured starter / rim gear 1 shown in FIGS. 2, 4 and 6 was manufactured by the method of the present invention based on the globe method. The starting material used as the starting point for this production was the processing material 100 (FIGS. 3 and 5) having a relatively small outer diameter. That is, in the method of the present invention, the outer diameter is increased due to the relationship relatively similar to the rolling operation to the solid material. This is because there is a plastic flow of material from the root to the end. (In short, as in the case of the known method mentioned at the beginning, the material is not fed into the cavity of the groove of the molding mandrel, which does not reduce the outer diameter.) Has a wheel flange 111 and a cylindrical peripheral wall 112 integrally connected to the wheel flange. In this case, it is assumed that the processing material 100 is made of a hardenable steel sheet.

The outer surface 114 and the inner surface 11 of the cylindrical peripheral wall 112.
In the present embodiment, the wall thickness 116 between the first and second wheels 5 is larger than the wall thickness of the wheel flange 111 (the reference numeral is omitted). However, if it is considered advantageous that the cylindrical peripheral wall 112 and the wheel flange 111 have the same wall thickness, it is also possible to use wheel flanges of the same wall thickness.

In this embodiment, the processing material 100 is a manufacturing apparatus 2 for carrying out the method of the present invention based on the glove system.
As shown in FIG. 1, cold plastic deformation processing is performed to form the starter / rim gear 1.

The manufacturing apparatus 2 (FIG. 1) is provided with a holding plunger 21 arranged in the machine frame 20 on the workpiece axis Z.
And the holding plunger is separated from the opposed plunger in response to the movement of the opposed plunger 22, which is also located on the workpiece axis Z. The work material 100 is chucked between the holding plunger 21 and the opposed plunger 22. At the time of this chuck, a centering member 23 similar to a cylindrical mandrel is engaged in the work material 100 to support the inner surface 115 of the work material and to move the work material axis Z.
Center.

The opposed plunger 22 is now a drive feed 24.
Thus, the work material 100 forming the work part is rotated in the direction of arrow R so that the work material 100 is rotated in synchronism with the rotary motion W of both rolling heads 3. The rolling head 3 is rotated by a known driving device (not shown), in which case the synchronization of the rotary movement W with respect to the rotary movement R of the workpiece 100 is accomplished by mechanical and / or electronic means known per se. By a known method.

Further, the drive feed table 24 is shifted in the axial direction indicated by the arrow A by the screw spindle 25 in synchronism with the rotational movement W of the rolling head.
The drive device 26 of No. 5 can also be controlled by electronic control means.

The rolling head 3 can be adjusted by the adjusting plunger in the direction of the double arrow D toward or away from the workpiece. In principle, both rolling heads 3
Is set to the correct spacing in the situation shown and remains in that position until the end of the rolling operation, or during the rolling operation both rolling heads are adjusted with respect to the numerical control axis according to the technical requirements. . When releasing the manufactured starter / rim gear, both rolling heads can be moved as required.

Each rolling head 3 has only one roll 3
2 is illustrated, the roll having a groove-shaped cross-section, but in this case it may have a slight atypical cross-section in order to compensate for the relatively slight elastic resilience. Of course. It is also possible to provide a plurality of rolls in order to change the drive state accordingly.

The rolling operation gradually produces the starter / rim gear 1 in a manner typical for the glove method (FIGS. 2, 4 and 6), the flange 11 of the rim gear being compared with FIG. 3 and FIG. As is clear from the above, it is almost equal to the wheel flange 111 of the workpiece 100 except that the edge region of the external tooth row 13 is plastically deformed to some extent. The outer toothing 13 is formed with a purely geometric rotating wheel shape, while the inner surface 15 fits the plunger with little or no change.

In the present invention, since the mandrel having sharp teeth does not exist, the wall thickness 16 (

FIG. 4) is relatively large, and as a result, in comparison with the prior art (

Refer to the description of "Prior Art") Starter in critical region
The load resistance and durability of the rim gear are significantly improved.

Above all, as can be clearly seen from the illustrations of FIGS. 2 and 4, the external toothing 13 is extremely tall (when measured in the radial direction), as is customary in starter rims. ,
Very thin (if measured in the axial direction). However, it goes without saying that the drawings hardly show the precision of the genuine rotary wheel tooth row.

Further, according to the working method of the present invention, it becomes possible to use a steel thin plate which is easily subjected to a surface treatment, for example, induction hardening, without causing a disadvantage in cold plastic deformation working.

[Brief description of drawings]

1 is a plan view of a glove type machine configured to carry out the method of the present invention for manufacturing the starter rim gear of the present invention.

FIG. 2 is an axial view of a starter / rim gear enlarged in comparison with FIG.

[Fig. 3] Fig. 2 shows the processing material before cold plastic deformation processing
FIG. 7 is an enlarged cross-sectional view taken along the line III.

FIG. 4 is a cross-sectional view of the manufactured starter / rim gear corresponding to FIG.

5 is a detailed cross-sectional view of a flange area of the work material surrounded by a chain line circle V in FIG. 2 taken along a direction perpendicular to the axis Z. FIG.

FIG. 6 is a detailed cross-sectional view of the rim area of the starter / rim gear.

[Explanation of symbols]

A Double arrow that indicates the axial feed direction of the processing material,
D Double arrow indicating the approaching / separating direction of the rolling head,
R Arrow indicating the rotational movement direction of the processing material, W Arrow indicating the rotation direction of the rolling head, Z Processing material axis line,
1 Starter / Rim gear, 2 Manufacturing equipment, 3
Rolling head, 11 starter / rim gear wheel flange, 12 starter / rim gear peripheral wall,
13 external tooth row provided on the peripheral wall, 14 root circle of the tooth groove base of the external tooth row, 15 inner surface of the peripheral wall, 16 wall thickness from the tooth groove base to the inner surface of the peripheral wall, 20 machine mount, 21
Holding plunger, 22 Opposite plunger, 2
3 centering member, 24 drive feed, 2
5 screw spindle, 26 screw spindle drive, 32 roll, 100 processing material,
111 wheel flange of machined material, 112 cylindrical peripheral wall of machined material, 114 outer surface of peripheral wall, 115
Inner surface of peripheral wall, 116 Thickness of peripheral wall of work material between outer surface and inner surface

Claims (5)

[Claims] 1. A cylindrical extension parallel to the workpiece axis (Z) and coaxial to produce a sheet metal starter / rim gear with an external toothing having a purely geometrical rotating wheel shape. A sheet metal blank (10) having a wheel flange (111) integrally connected to the peripheral wall (112) and extending radially from the outer periphery toward the workpiece blank axis (Z).
The peripheral wall (112) of 0) is subjected to cold plastic deformation processing based on the globe method to form an external tooth row (13) having a purely geometric rotating wheel shape. In the manufacturing method of rim gear, processing material (10
The wall thickness (116) of the peripheral wall (112) of (0) is changed by cold plastic deformation processing based on the glove method, and the root circle (14) of the tooth groove base of the outer tooth row (13) is manufactured. Distance (16) to the shortest point on the inner surface (15) of the peripheral wall (12)
Is smaller than the wall thickness (116) of the peripheral wall (112) of the work material (100), and the root circle (14) of the external tooth row (13) is A method of manufacturing a starter / rim gear made of sheet metal, which is characterized in that it is always extended inside the manufactured peripheral wall (12). 2. A mandrel (2) is formed by cold plastic deformation processing of a work material peripheral wall (112) for forming a rim gear peripheral wall (12).
3) The manufacturing method according to claim 1, which is carried out above. 3. The cold plastic deformation working of the workpiece peripheral wall (112) for forming the rim gear peripheral wall (12) is carried out on a mandrel (23) having a cylindrical or corrugated sectional shape.
The manufacturing method according to claim 2. 4. A wheel flange (11) extending radially from the outer periphery toward the workpiece axis (Z),
At the outermost position in the radial direction of the wheel flange, a peripheral wall (12) as a gear rim that extends in a tubular shape parallel to and coaxial with the work material axis (Z) and cold plastically deformed based on the globe method. Are integrally molded, and the peripheral wall is
Sheet metal made by the method according to claim 1, in the form of an external tooth row (13) made of cold-plastically deformed steel sheet and having a purely geometric rotating wheel shape. In the starter / rim gear (1) made of a material, the root circle (14) of the external tooth row (13) always extends inside the manufactured peripheral wall (12) having the external tooth row (13). Starter rim gear characterized by. 5. The inner surface (15) of the peripheral wall (12) has a cylindrical or corrugated cross-section.
The starter / rim gear described.