JPH11179481A - Method of manufacturing center ring for transmission - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To ensure the hardness of a nail portion without performing heat treatment. SOLUTION: A claw portion is formed from a ring material by forging, and then processed into a semi-finished product having an inner surface taper portion and an outer surface taper portion, and height grooves are formed in the inner surface taper portion and the outer surface taper portion. Formed by cold forging.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a center ring mounted on a manually operated transmission used in automobiles, construction machines, agricultural machines, and the like.

[0002]

2. Description of the Related Art The outline of a double cone synchromesh mechanism of a manually operated transmission used in automobiles, construction machines, agricultural machines, and the like will be described with reference to a longitudinal sectional view of FIG. A clutch gear 3 is fixed to a side surface of the transmission gear 2. An inner cone 4 and an outer cone 5 are provided on the side of the clutch gear 3 in a state where the inner cone 4 and the outer cone 5 are fitted with an inclined cylindrical surface. A center ring 6 is interposed between the inner cone 4 and the outer cone 5. ing. A synchronizer sleeve 7 is spline-fitted to the outer periphery of the outer cone 5, and the synchronizer sleeve 7 is
To shift right and left in FIG.

During gear shifting, when the synchronizer sleeve 7 is shifted to the left in FIG. 7 by the shift fork 8, the inner tapered portion of the outer cone 5 and the outer tapered portion of the center ring 6 come into contact with each other to generate a frictional force. Further, the inner diameter tapered portion of the center ring 6 and the outer diameter tapered portion of the inner cone 4 come into contact with each other, and the center ring 6 receives frictional force from inside and outside.

[0006] A claw portion is formed on the left end surface of the center ring 6 in FIG. 8 as described later, and the claw portion transmits a rotational force to the clutch gear 3 through a hole 9 formed in the clutch gear 3. As a result, a rotational force is transmitted from the synchronizer sleeve 7 to the transmission gear 2 via the outer cone 5, the center ring 6, and the clutch gear 3.

When the synchronizer sleeve 7 moves further to the left, the rotational force transmitted to the transmission gear 2 further increases, and finally the rotation speed of the transmission gear 2 becomes the same as the rotation speed of the synchronizer sleeve 7. The spline of the niser sleeve 7 is combined with the spline on the outer periphery of the clutch gear 3, and the speed change operation is completed.

FIG. 1 is a longitudinal sectional view of the center ring 6 described above, and FIG. 2 is a plan view of FIG. 1, wherein a claw portion 10 is projected from one end surface of the center ring 6. As is clear from FIG. 1, the diameter of the end face of the center ring 6 where the claw portion 10 protrudes is larger than the diameter of the other end face, and the center ring 6 is a cone-shaped ring. ing. On the inner surface of the center ring 6, a number of grooves 11 are provided in the center line direction of the center ring 6, and on the outer surface of the center ring 6, a number of grooves 12 are provided in the center line direction of the center ring 6. Have been.

The grooves 11, 12 are generated by friction because the center ring 6 is sandwiched between the inner cone 4 and the outer cone 5 as shown in FIG. It is indispensable to release the wear pieces, and since the claw portion 10 is a portion that is inserted into the hole 9 formed in the clutch gear 3 and transmits the driving force, it is required to have strength and wear resistance. You. Therefore, after the center ring 6 is polished, molybdenum having wear resistance is applied to the inner and outer tapered portions by thermal spraying, and the inner and outer tapered portions are slid and used.

Conventionally, the center ring 6 shown in FIGS. 1 and 2 has been manufactured through a number of steps as described below.

First, a ring-shaped material 13 as shown in FIG.
Is processed into a cone-shaped semi-finished product having an inner surface taper and an outer surface taper by NC processing, and then the claw portion 10 is processed into an upright shape by a polygon machine, and the claw portion 1 is processed.
The side of 0 is machined into a cylindrical shape by a machining center.

Next, the inner groove 11 and the outer groove 12 shown in FIGS. 1 and 2 are cut by a plunge cutter or a machining center, and the entire center ring 6 is carburized or quenched or the claw portion 10 is induction-hardened. In order to secure the hardness of the claw portion 10 and finally grind the inner and outer surfaces, the center ring 6 was manufactured.

[0011]

As described above, conventionally, in order to secure the hardness of the claw portion 10 of the center ring 6, heat treatment such as carburizing or induction hardening is performed.
The heat treatment process and the heat treatment cost are required, and the entire center ring 6 is deformed due to the heat treatment. Therefore, there is a problem that the polishing allowance for the last inner and outer surfaces is increased and the polishing time is long.

The present invention solves such a problem and provides a method of manufacturing a center ring for a transmission in which the hardness of a claw portion can be ensured by using work hardening by cold forging without performing heat treatment. It is intended to provide.

[0013]

According to the present invention, a claw portion is formed from a ring material by cold forging, warm forging, or hot working, and then the inner surface is tapered based on the claw portion. Machined into a cone-shaped semi-finished product by machining the part and the outer tapered part, and forming the semi-finished product into a number of grooves in the height direction in the inner tapered part and the outer tapered part by cold forging. This is a method for manufacturing a transmission center ring.

A method of forming a large number of grooves in the height direction of the inner tapered portion and the outer tapered portion of the semi-finished product by cold forging is described as an example in Japanese Patent Application No. Hei 9 (1994) -109, filed by the present inventors.
No.-330143 "Method of forming center ring for transmission".

The hardness of the nail after forging is HB1.
The area reduction rate is 20 to 8 so as to fall within the range of 83 to 240.
By performing forging by selecting from the range of 0%,
Carburizing and induction hardening can be omitted.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below.

In the method of the present invention, an outer diameter of 130 mm and an inner diameter of 11 mm shown in FIG.
The ring member 14 is 4 mm in height and 13 mm in height.

After annealing and bonding the ring material 14,
A load is applied by a hydraulic press and extruded by cold forging at a cross-sectional reduction rate of 20 to 80%.
In addition, the semi-finished product 15 having an outer diameter of 129 mm, an inner diameter of 114 mm, a height of 10 mm, a height of the claw portion 10 of 7.5 mm, and a thickness of 4 mm was formed.

The semi-finished product 15 is machined to have an outer diameter of 1 mm.
A semi-finished product having a diameter of 28 mm, an inner diameter of 119 mm, a height of 8 mm, a height of the claw portion of 3.4 mm, and a thickness of 3 mm was processed and then subjected to cold forging to obtain a center ring 6 shown in FIGS.

Table 1 summarizes the molding conditions so far.

[0021]

[Table 1]

In the present example, the hardness (1) of the claw portion 10 extruded at a cross-sectional reduction rate of 60% by applying a load of 500 tons with a hydraulic press and the conventional JIS4051 S45
C, Table 2 shows a comparison between the hardness (2) of the claw portion 10 heat-treated at a heating temperature of 820 to 870 ° C.

[0023]

[Table 2]

[0024]

[Table 3]

Thus, it can be seen that the hardness of the claw 10 formed by the method of the present invention is equal to or higher than the hardness of the conventionally heat-treated claw 10.

The circumferential hardness of the ring in the vicinity of the claw portion 10 is HB183-240, and the circumferential hardness of the ring during conventional normalization is HB167-227. The center ring for a transmission manufactured by the company has a performance that sufficiently satisfies the circumferential hardness of the ring. Also, depending on the shape of the center ring, the predetermined hardness may be insufficient in S20C due to the relationship of the deformation rate. In such a case, the required hardness can be obtained by changing the material.

The method of forming a number of grooves in the height direction on the inner surface taper portion and the outer surface taper portion by cold forging on the semi-finished product described above is disclosed in Japanese Patent Application Laid-Open No. Hei 9 (1998) -197, as shown in the longitudinal sectional view of FIG. 3
No. 30143, "Method of forming center ring for transmission" will be described.

The grooves 11, 1 of the center ring 6 shown in FIG.
2 is formed by using a claw 10 as shown in FIGS.
An inner surface taper and an outer surface taper are machined into a cone-shaped semi-finished product 15 having the following shape, and the claw portions 10 thereof are fitted into grooves 17 on the upper edge of a knockout ring 16 shown in FIG. Next, the ram 26 is lowered so that the lower edge of the upper bunch 32 contacts the upper edge of the semi-finished product 15, and at the same time, the upper die 27 fits on the outer periphery of the semi-finished product 15.

When the ram 26 is further lowered, the upper punch 32 and the upper die 27 are also lowered from the ram 26 through the stopper 29, the elastic body 30, and the upper pressure plate 31. In this state, the elastic body 30 is compressed and the upper pressure plate 31 and the upper punch 32 rise with respect to the ram 26 and the upper die 27, and the upper surface of the upper pressure plate 31 comes into contact with the lower end of the stopper 29. , Lower knockout ring 16
Is pushed downward, and the lower pressure plate 18, the vertical bar 19, the pin 20,
The pressure plate 21 and the lower support 22 are slightly lowered together with the pressure plate 21. The semi-finished product 15 is restrained by the lower punch 23, the upper die 27, the upper punch 32, and the knockout ring 16,
The groove 12 (see FIG. 2) is formed on the outer surface of the semi-finished product 15 by the protrusion 28 of the upper die 27, and at the same time, the groove 11 is formed on the inner surface of the semi-finished product 15 by the protrusion 25 of the lower punch 23. 1. The center ring 6 shown in FIG. 2 is formed.
The binding force on the semi-finished product 15 at this time can be changed by adjusting the thicknesses of the lower pressure plate 18 and the upper pressure plate 31.

When the center ring 6 has been formed, the ram 2
When the pressure plate 21 is raised by means of fluid pressure or the like, the knockout ring 16 is pushed up via the pin 20, the vertical bar 19 and the lower pressure plate 18, so that the center ring 6 is removed from the knockout ring 16. Can be taken out.

[0031]

According to the method of the present invention, the required hardness of the nail portion can be obtained without heat treatment, so that the time and cost of the heat treatment are not required, and the cost can be reduced. There is an effect of improving.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a center ring.

FIG. 2 is a plan view of FIG.

FIG. 3 is a longitudinal sectional view of a ring-shaped material.

FIG. 4 is a longitudinal sectional view of a state in which the ring-shaped material of FIG. 3 is first processed.

FIG. 5 is a longitudinal sectional view of a semi-finished product.

FIG. 6 is a plan view of FIG. 5;

FIG. 7 is a cross-sectional view of an example of a centering forming apparatus.

FIG. 8 is a longitudinal sectional view showing a use state of the transmission center ring.

[Explanation of symbols]

 10 Claw part 13 Ring-shaped material 15 Semi-finished product

Claims (2)

[Claims] 1. A claw portion is formed by forging from a ring material, and then processed into a semi-finished product having an inner surface taper portion and an outer surface taper portion. Then, height grooves are formed in the inner surface taper portion and the outer surface taper portion. A center ring for a transmission, which is formed by cold forging. 2. The method of manufacturing a center ring for a transmission according to claim 1, wherein the pawl portion is formed by forging with a cross-sectional reduction rate of 20 to 80%.