JP2646726B2 - Drive plate manufacturing method - Google Patents

Description

Description: Object of the Invention (Industrial application field) The present invention relates to a method of manufacturing a thin and large-diameter gear by press-forming a thin steel plate, and is used for a torque converter of an automobile. It is used as a method for manufacturing a drive plate.

(Prior Art) As a prior art relating to the present invention, there is JP-A-63-60037.

This is a method of manufacturing a large-diameter gear in which the peripheral portion is thick and the central portion is thin. Forming a tooth portion on the thick portion by a gear rolling device and subjecting the tooth portion to a heat treatment by quenching in a heat treatment step. .

(Problems to be Solved by the Invention) However, in the method of manufacturing the drive plate, as shown in FIG.
The tooth profile is deformed easily because it is heavily bent to form a tooth profile after thickening and heat treatment of the tooth profile.

Fig. 13 is an enlarged view of the tooth profile of the drive plate,
4-fold bent tooth profile formed from thin steel plate of m
In the case of 1, the tensile stress is applied to the heat treatment by the plate portion 22 of the drive plate, and the center of the tooth portion is opened as shown in B, and the tooth bottom in the upper portion of the tooth portion is displaced as shown in A, resulting in a stepped shape and a defective tooth shape. Occurs.

The cause of this tooth shape defect is that the teeth 21 are restrained up and down by heat treatment restraining jigs 23 and 24 indicated by dashed lines, and quenching is performed by applying high frequency heating and cooling liquid from the outer diameter side of the teeth. Because of the local heat treatment, thermal expansion and contraction due to heating and cooling occur in each part, and a difference is generated. That is, the deformation A has a difference in expansion between the side connected to the thin steel plate having a small thermal expansion at the time of heating and the other portion having a large thermal expansion at the time of heating, resulting in a displacement A at the boundary portion, and the deformation B at the time of cooling. A difference in the amount of expansion and contraction occurs between the side of the tooth portion connected to the thin steel sheet and the opposite side (lower side), and downward bending occurs at the joint of the tooth tip, resulting in the opening B at the tooth tip. .

The present invention relates to a method of manufacturing a drive plate in which the outer periphery of a thin steel plate is bent four times to form a tooth profile and heat-treated. It is a technical object of the present invention to provide a method for manufacturing a drive plate that does not have an opening and does not have a deformed tooth tip.

[Configuration of the invention]

(Means for Solving the Problem) The technical means taken to solve the problem are as follows. That is, in a method of manufacturing a drive plate made of a thin steel plate having a large-diameter gear whose outer peripheral portion is thick and whose central portion is thin, (1) the outer periphery of the disk is bent into a cup shape, and the cup-shaped side wall is formed. (2) The step size, which is the length of the neck connected to the thick portion forming the tooth shape with the center of the thin steel plate, is twice the thickness of the thin steel plate. (3) The drive section is manufactured by plastically forming a tooth profile portion on the thick portion with a gear rolling device and performing heat treatment.

(Action) By making the length of the neck connected to the central plate portion of the drive plate and the thick portion forming the tooth profile twice or more the thickness of the thin steel plate, the thermal expansion and contraction during heat treatment causes The deformation of the tooth part caused by the difference in expansion and contraction between the connection side (upper side) and the opposite side (lower side) of the thin steel sheet (tooth bottom shift A) and the tooth tip opening B) are caused by the connection with the thin steel sheet. The difference in expansion and contraction between the upper and lower portions of the teeth is suppressed by the axial net portion, and the deformation of the teeth is greatly reduced.

Example An example will be described below.

Example 1 As shown in FIG. 1, a cup-shaped can 2 is formed by press-drawing a thin disk-shaped steel sheet 1 having a thickness of tmm, and reference numeral 3 denotes a peripheral wall portion of the cup-shaped can.

As shown in FIG. 2, the joint (net base) 4 between the central portion 1a of the thin steel plate and the thick portion of the peripheral wall portion 3 is formed to a double thickness 5 with a length of 2 tmm or more.

Next, by pressing the mandrel, the constraining ring, the punch, the die, etc., the seat is bent as shown in FIG. 3 to double the thickness, and the cup-shaped can peripheral wall portion is totally quadrupled as shown in FIG. It is formed into a rolling blank 7.

Next, a tooth profile 8 is formed on the quadruple thick portion 6 of the rolling blank 7 by gear rolling, as shown in FIG.

Next, as shown in FIG. 5, in order to improve the strength and wear resistance of the teeth, only the teeth are heat-treated. The teeth 8 are restrained and held by the heat treatment restraining jig upper 9a and the lower 9b.
Only the tooth portion 8 is heated to a predetermined temperature by the heating coil of the induction hardening device 10, and immediately thereafter, a cooling liquid is applied, rapidly cooled, and quenched to manufacture a large-diameter gear.

Embodiment 2. As shown in FIG. 6, when the joint length (net length) of the thin steel plate portion 11 and the tooth portion 12 is less than twice the thickness tmm of the thin steel plate due to the product design, the opposite side of the thin steel plate is used. Take the net length H 2t
mm or more.

As shown in FIG. 6, a thin disk material is drawn into a hat-like shape 12 by press drawing. At this time, the drawing depth 13 is set so that the neck length, which is a feature of the present invention, is at least twice the thickness tmm of a thin steel plate.

Next, the blank squeezed into a hat shape is drawn into a cup shape 14 as shown in FIG. 7, and the side wall portion is formed as shown in FIG.
Then, the peripheral wall portion is subjected to countersunk bending to form a rolling blank 17 having a quadruple thick portion 16 as shown in FIG.

Next, as shown in FIG. 10, a large-diameter gear 18 is formed by forming and quenching teeth as in the first embodiment.

(A) 19a and (b) 19b in FIG. 11 show the state of contraction and expansion due to the heat treatment in Examples 1 and 2, and the dotted line indicates contraction, and the dashed line indicates expansion, and the tooth root shift due to contraction and expansion. And the occurrence of opening of the tooth tip is something that one does not want to wait for.

FIG. 14 is a diagram showing the relationship between the tooth root shift amount A and the net length H in the case of the first embodiment. As H increases, the shift amount A decreases.

FIG. 15 is a diagram showing the relationship between the opening length B of the tooth tip and the neck length H. As H becomes larger, the opening of the tooth tip becomes smaller.

〔The invention's effect〕

 The present invention has the following effects.

The precision of the gear is improved, the precision defect is greatly improved, and the improvement in the precision of the gear improves the contact with the mating part, thereby improving the wear resistance.

[Brief description of the drawings]

1 to 5 are explanatory views in which part of the first embodiment is omitted. FIG. 1 is a cup-shaped can, FIG. 2 is double bending, FIG. 3 is quadruple bending, and FIG. FIG. 5 is an explanatory view of each step of quenching, FIGS. 6 to 10 are explanatory views in which a part of the second embodiment is omitted, FIG. 6 is a hat shape, and FIG. FIG. 8 shows double bending, FIG. 9 shows quadruple bending, FIG. 10 shows tooth formation, FIG. 11 is an explanatory view of contraction and expansion, and FIG. An example (b) is a second embodiment. FIG. 12 is a cross-sectional view of the conventional example with a part omitted, FIG. 13 is an explanatory diagram of a main part of the conventional example when a failure occurs, and FIGS.
It is a figure which shows the relationship between the length H of the net, the gap A of a tooth bottom, and the opening B of a tooth tip in the case of an Example. 1,11: Thin steel plate, 2,14: Cup-shaped can, 4,13: Neck length, 6,16: Four thick parts.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Minoru Takahashi 2-1-1 Asahi-cho, Kariya-shi, Aichi Prefecture Inside Aisin Seiki Co., Ltd. (72) Inventor Yuji Sakabe 11, Nodamachibawari, Kariya-shi, Aichi Prefecture Aisin Yutaka Examiner in Yoko Co., Ltd. Tomoya Kato (56) References JP-A-62-84846 (JP, A) JP-A-62-270234 (JP, A) JP-A-63-286232 (JP, A)

Claims (1)

(57) [Claims] 1. A method of manufacturing a drive plate made of a thin steel plate having a large-diameter gear whose outer peripheral portion is thick and whose central portion is thin, comprising: (1) bending the outer periphery of a disk into a cup-like shape; The side wall of the thin steel plate is bent to form a quadruple thick portion. (2) The length of the neck connected to the central portion of the thin steel plate and the thick portion forming the tooth shape is set to 2 times the thickness of the thin steel plate.
(3) A method of manufacturing a drive plate in which a tooth profile is plastically formed on the thick portion by a gear rolling device and heat-treated.