JP3251169B2 - Sheet metal gears - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet metal gear formed by molding a sheet metal material.

[0002]

2. Description of the Related Art Gears are employed in mechanical parts for transmitting rotation such as power transmission. These gears have recently
There is a sheet metal gear formed by forging (press) forming as disclosed in Japanese Patent Application Laid-Open No. 6-75517 because of its advantages in terms of cost and light weight.

[0003] In this sheet metal gear, a thin sheet metal material is subjected to drawing to form an annular peripheral wall, and the peripheral wall is forged and formed using a mold corresponding to the tooth shape, and the required teeth are formed in the same portion. It is formed by forming a number of teeth having a shape in the circumferential direction.

[0004]

However, in order to obtain a gear having high tooth strength in such a sheet metal gear,
Using a thick sheet metal material and a mold (consisting of a die and a punch) corresponding to the tooth shape with an increased tooth surface wall, the thickness of the walls forming the tooth surfaces on both sides Is increased.

[0005] However, such gears with increased strength have the disadvantage that the weight of the gears is increased due to the increase in the thickness of the entire gears, and the weight reduction, which is an advantage of sheet metal gears, is impaired. Moreover, in order to obtain a gear with increased strength, it is necessary to change the thickness of the sheet metal material or to use a mold corresponding to the tooth having an increased wall thickness, which is disadvantageous in terms of manufacturing.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sheet metal gear which is capable of increasing the strength of teeth while reducing the weight and which is advantageous from the viewpoint of manufacturing. Is to do.

[0007]

According to a first aspect of the present invention, there is provided a sheet metal gear, wherein a thickness of a wall of a tooth surface to which a load is applied when driving force is transmitted is thicker than other tooth surface portions. The reason for this is that the teeth are formed on the sheet metal material by making the thickness uneven.

[0008] The sheet metal gear according to the first aspect is a gear in which only the thickness of the wall portion of the tooth surface where strength is required is increased as compared with other portions. Thereby, an increase in weight due to an increase in the strength of the teeth is suppressed.

Therefore, the strength of the sheet metal gear is increased while the weight is reduced. In addition, this sheet metal gear is designed so that the thickness of the wall of the tooth surface to which a load is applied during transmission of driving force is increased, for example, the relative distance between the die and the punch forming the mold without changing the thickness of the sheet metal material. By simply shifting the position, a sheet metal gear with increased tooth strength can be manufactured, which is advantageous from the viewpoint of gear manufacture.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on a first embodiment shown in FIGS. FIG. 1 shows an external view of, for example, an automatic transmission device for an automobile. In the figure, reference numeral 1 denotes an input shaft of the device.

An input shaft section 1 receiving an output of an engine (not shown) is connected to a transmission section 3 (not shown) via a torque converter 2 as shown in FIG.

A drive plate 6 is mounted on a front surface of a cover 2a that covers a converter turbine (not shown) of the torque converter 2. Drive plate 6
Is formed in a disk shape, and a starter device 4
A gear made of a sheet metal, for example, a ring gear 5 that can mesh with the pinion gear 4a is integrally provided.

As shown in FIG. 3, the ring gear 5 is formed by, for example, bending the outer peripheral end of the drive plate 6 outward in a direction substantially parallel to the axis to form an annular peripheral wall 7 (sheet metal material). The teeth 8 are formed on the outer periphery using forging molding as disclosed in JP-A-6-75517.

That is, as the ring gear 5, a thin flat plate 9 punched in a disk shape is used as a material common to the drive plate 6. Then, as shown in FIGS. 4 (a) and 5 (a), the flat plate 9 is subjected to drawing by a processing machine 9d having an upper punch 9a, a lower punch 9b, and a die 9c. After forming the peripheral wall 7, the peripheral wall 7 is forged and formed in a mold 10 corresponding to the tooth shape to form a large number of teeth 8 having a required tooth shape on the outer peripheral portion of the peripheral wall 7.

Specifically, for example, before forging, FIG.
As shown in FIG. 5 (b) and FIG. 5 (b), as a preliminary tooth formation shape, mountain-shaped projections 11 are formed at predetermined intervals on both sides of the peripheral wall 7 on the inner peripheral surface along the axial direction of the peripheral wall 7. Further, drawing forming is performed in which the upper punch 12a and a die 14 in which a valley-shaped tooth shape portion 13 combined with the ridge 11 is formed at a predetermined interval on the outer peripheral surface. Reference numeral 12b indicates a lower punch. Then, as shown in FIGS. 4 (c) and 5 (c), the peripheral wall 7 of the preliminary tooth forming part 15 is formed by an upper punch having a ridge 16 (only shown in FIG. 5) corresponding to a desired tooth shape. 17a (tooth-shaped punch) and a die 19 also having a tooth-shaped portion 18 (both constituting the mold 10)
And a forging punch 20 interposed therebetween so as to crush the peripheral wall 7 from the tip. 17b denotes a lower punch.

As a result, the peripheral wall 7 buckles, and the tooth-shaped teeth 7 conforming to the shape of the tooth profile 18 are formed on the outer peripheral portion of the peripheral wall 7.
... are formed. As shown in FIG. 3, the thickness B of the wall portion 7b of the peripheral wall 7 forming the tooth surface 8b to which the load of each tooth 8 is applied as shown in FIG.
Is thicker than the thickness A of the wall portion 7a of the peripheral wall 7 forming the other tooth surface portion, that is, the tooth surface 8a on which the load on the opposite side is small.

To make only the thickness of the wall portion 7b different (A <B), the above-described steps in the molding direction are used as they are. Specifically, FIGS. 4B and 5
As shown in (b), for example, in the preliminary tooth forming step, the ridge 11 of the upper punch 12a and the tooth profile 1 of the die 14 are formed.
3 is shifted in the circumferential direction, and the distance a between the protruding ridge 11 and the tooth profile 13 which is a region for forming the wall 7a;
By setting the distance b between the protruding ridge 11 and the tooth profile portion 13 as the region where the wall portion 7b is formed to have a relationship of “a <b”, the preliminary tooth forming shaped product in which the thickness of the teeth 4 is different on both sides 15 is molded.

In the forging process, for example, FIG.
(C) and the upper punch 17 as shown in FIG.
The relative position between the ridge 16 of FIG. 1A and the tooth profile 18 of the die 19 is shifted in the circumferential direction, and the ridge 1 serving as a region for forming the wall 7a
A distance c between the tooth 6 and the tooth profile 18 and a distance d between the ridge 16 and the tooth profile 18 which are regions for forming the wall 7b are set in a relationship of “c <d”, As described above, the preliminary tooth forming part 15 is forged.

Then, in the peripheral wall portion of the preliminary tooth forming part 15, a movement of the material occurs such that the wall thickness is increased from the wall 7a on the side where the strength is not required to the wall 7b where the strength is required. .

As a result, in the preform 15, only the wall 7b of the tooth surface 8b to which a load is applied is locally thickened, and the teeth 8 having a desired shape are formed. The ring gear 4 configured as described above is a sheet metal gear in which only the thickness of the wall portion 7b of the tooth surface 8b where strength is required is increased compared to other portions.

That is, in the sheet metal gear, only the portions of the teeth 8 where strength is required are effectively reinforced by uneven thickness, and an increase in weight due to an increase in strength is suppressed. Therefore,
The strength of the sheet metal gear is increased while the weight is reduced.

In addition, the sheet metal gear is formed so that only the thickness B of the wall 7b of the tooth surface 8b to which a load is applied is increased.
Since only the thickness is biased by forging, the relative position between the upper punch 17a and the die 18 constituting the mold 10 is shifted without changing the thickness of the sheet metal material as described above. Sheet metal gears with increased strength can be easily manufactured, which is advantageous in terms of manufacturing. Of course, in the preliminary tooth formation type, it is only necessary to shift the relative position between the upper punch 12a and the die 14.

In the first embodiment, the preliminary tooth forming die 1 is formed by using the tooth-shaped upper punch 17a having the ridge 16.
5 was formed by forging, but the invention is not limited thereto. For example, a cylindrical upper punch 21 having a smooth outer peripheral surface and a forging punch 22 having a smooth inner peripheral surface as in the second embodiment shown in FIGS. Alternatively, the thickness of the wall portion 7b of the tooth surface 8b to which a load is applied may be formed so as to be thicker than other portions.

In the first embodiment, the present invention is applied to the ring gear 5 (sheet metal gear) integrated with the drive plate 6. However, the present invention is not limited to this. For example, as shown in FIGS. 6 may be applied to the ring gear 5 (sheet metal gear) attached to the cover 2 a of the torque converter 2.

Of course, in each embodiment, the example in which the present invention is applied to a gear constituting a power transmission system of an automatic transmission device for a vehicle has been described, but the present invention is not limited to this.
In another device, the present invention may be applied to a sheet metal gear used in a mechanical part that transmits rotation such as power transmission. In the second embodiment and the third embodiment, the same parts as those shown in the respective drawings of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

[0026]

As described above, according to the first aspect of the present invention, only the thickness of the tooth surface wall to which a load is applied at the time of driving force transmission is required to increase in strength, compared to other portions. The obtained sheet metal gear is obtained.

[0027] Thus, only the portion where the strength is required is reinforced, and the weight increase accompanying the increase in the strength of the teeth can be suppressed.
As a result, it is possible to obtain a sheet metal gear that achieves both increased strength and reduced weight of the teeth.

In addition, the sheet metal gear has a die and a punch forming a mold without changing the thickness of the sheet metal material so that only the thickness of the wall of the tooth surface to which a load is applied when driving force is transmitted is increased. By simply shifting the relative positions of the gears, a sheet metal gear with increased tooth strength can be manufactured, which is advantageous from the viewpoint of gear manufacture.

[Brief description of the drawings]

FIG. 1 is a perspective view illustrating an automatic transmission device for a vehicle having a sheet metal gear according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a torque converter having a sheet metal gear of the apparatus.

FIG. 3 is a perspective view for explaining the structure of the sheet metal gear.

FIG. 4 is a perspective view for explaining a process until a gear made of sheet metal with a thickened tooth surface to which a load is applied is formed on an outer peripheral end of the plate using a drive plate as a sheet metal material.

FIG. 5 is a sectional view of the same.

FIG. 6 is a perspective view for explaining forging forming using a cylindrical punch, which is a main part of a second embodiment of the present invention.

FIG. 7 is a sectional view of the same.

FIG. 8 is a perspective view for explaining an automatic transmission device for a vehicle having a sheet metal gear separate from a drive plate according to a third embodiment.

FIG. 9 is a cross-sectional view showing a torque converter having sheet metal gears of the apparatus.

FIG. 10 is a perspective view for explaining the structure of the sheet metal gear.

[Explanation of symbols]

 5: ring gear (sheet metal gear) 7: peripheral wall (sheet metal material) 8b: tooth surface on the side to which load is applied 12, 17, punch 14, 19 ... die 20: forging punch.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F16H 55/17 B21K 1/30

Claims (1)

(57) [Claims] 1. A gear made of sheet metal, wherein teeth are formed on a sheet metal material by making the thickness of a wall portion of a tooth surface to which a load is applied at the time of driving force transmission thicker than other tooth surface portions. .