JPS6195732A - Manufacture of axis with stop ring - Google Patents

Abstract

PURPOSE:To improve the efficiency of fitting a stop ring by cooling split stop- ring to the inherent Ms point or less of ring, and successively heating the plural number of said rings to the Af point or less to memorize their shapes, while restricting from the outside of the outer diam. of ring. CONSTITUTION:A split stop ring 1 consists of a shape memory alloy such as a Ni, Ti alloy, and is obtained by forming a coiled spring and cutting it one at a time. Many stop rings 1 are inserted to a round mandrel 5 having an outer diameter equal to the diameter of the groove 4 of an axis 2, and are cooled to the inherent Ms point or less of ring 1 to make them deformable, and then the mandrel 5 is inserted into a cylindrical body 8 to form a jig 6. Next, the jig 6 is heated in the nonoxidative atmosphere of a furnace in a state of ristricting the rings 1 to memorize their shapes. Then, the ring 1 can be easily fitted to the groove 4 by cooling and heating the ring 1 provided with the shape memory treatment, to return it to the memorized shape. Therefore, the efficiency of fitting is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a shaft with a retaining ring in which a split retaining ring is fitted into an annular groove of the shaft by shape memory heat treatment.

Conventionally, such a shaft with a retaining ring has been made by mechanically fitting a split retaining ring made of fine spring steel wire with a circular or rectangular cross section into an annular groove of the shaft. However, since the inner diameter of the split retaining ring is equal to the outer diameter of the annular groove, it is necessary to use a special tool to spread the split retaining ring in order to fit it into the annular groove, which poses a problem in terms of work efficiency. .

An object of the present invention is to provide a method for manufacturing a shaft with a retaining ring in which a split retaining ring is fitted into an annular groove of the shaft through shape memory heat treatment using the property of shape memory without requiring a pushing operation using a tool. It is about providing.

The split retaining ring used in the present invention is made of a thin wire made of a shape memory alloy of nickel-titanium alloy or copper-zinc-aluminum alloy and has a circular or rectangular cross section, and is tightly wound with an inner diameter that is equal to or slightly smaller than the shaft diameter. It is made by winding it into a coiled spring shape and then cutting it one by one into rings with an effective inner circumferential length equal to the circumferential length of the annular groove of the shaft. This split retaining ring is cooled to a temperature below the retaining ring's unique Ms point (martensitic transformation start temperature) to make it deformable, and the diameter is reduced to an inner diameter equal to the diameter of the annular groove of the shaft. After simultaneously restraining the inner and outer diameter parts in this reduced diameter state and heating and maintaining them at a temperature of 300 to 500°C above the Af point (austenite transformation end temperature), the split retaining ring memorizes the shape. The split retaining ring subjected to the shape memory heat treatment is cooled to a temperature below its unique Ms point to make it deformable, and the annular groove 1. :'Insert, heat above the Af point to return the retaining ring to the memorized shape, and firmly fit it into the annular groove.

A method of manufacturing a shaft with a retaining ring according to the present invention will now be described in detail with reference to the accompanying drawings.

As mentioned earlier, the split retaining ring 1 is made by cutting a tightly wound coil of fine wire of a shape memory alloy of nickel-titanium alloy or copper-zinc-aluminum alloy into a ring, and its inner diameter is the same as that of the shaft 2. It is equal to or slightly smaller than the outer diameter. As shown in FIGS. 2 and 3, the split retaining ring 1 has a circular or rectangular cross-sectional shape and has a split portion 3, and the effective inner circumference excluding the split portion 3 is equal to the mottled groove of the shaft. It is approximately equal to the circumference length of 4.

A large number of split retaining rings 1 are fitted into a round bar core 5 having an outer diameter equal to the diameter of an annular groove 4 of a shaft 2. The heat treatment jig 6 has a bottom plate 7 at its lower end.
A cylindrical body 8 is screwed onto the cylindrical body 8, a cap 9 is screwed onto the upper end of the cylindrical body 8, and a number of split retaining rings 1 on a round bar core 5 are crimped inside the cylindrical body 8 through the cap 9. It consists of a spacer 10 for holding. The cylindrical body 8 has a tapered guide portion 11 in its artificial part, which makes it easy for the split retaining ring 1 to enter into the cylindrical body 8. The cylindrical body 8 also has an inner diameter equal to the outer diameter of the annular groove of the shaft plus twice the wire diameter of the retaining ring, and serves to restrain the retaining ring from the outside. Then, a large number of split retaining rings 1 are fitted onto the round bar core 5 and cooled below the unique Ms point (martensitic transformation starting temperature) of the retaining ring to make it deformable, and the round bar core 5 is made deformable. Insert into the cylindrical body 8. In such a case, the split retaining ring 1 is sequentially inserted and guided by the tapered guide portion 11 to reduce its diameter.
It is in close contact with the round bar core metal 5, and the inner diameter part is restrained by the round bar core metal 5, and the outer diameter part is restrained by the inner surface of the cylindrical body 8, respectively. When the spacer 10 is fitted onto the round bar core 5 and the cap 9 is screwed into the cylindrical body 8, the retaining rings 1 are brought into close contact with each other, and the upper and lower surfaces are shaped to be parallel to each other.

Next, put this jig into a non-oxidizing atmosphere furnace and attach the retaining ring to its A.
f point (austenite transformation end temperature) or higher, e.g. 300
Heat and hold at ~500°C for 1 to 5 hours to memorize the shape of the retaining ring, then take the jig out of the furnace, cool it, and take out the retaining ring from the jig. The retaining ring 1 is cooled to a temperature below its own Ms point to make it deformable, and is fitted into the annular groove 4 of the shaft 2. Then Af
When heated above a certain point, the retaining ring 1 returns to its memorized shape and firmly adheres to the annular groove 4 of the shaft 2, thereby making it possible to obtain a shaft with a retaining ring.

As can be seen from the above, according to the present invention, the split retaining ring is formed of a shape memory alloy, and the shape of the inner diameter equal to the diameter of the annular groove of the shaft is memorized in advance through heat treatment. The ring can be simply and easily fitted into the groove, and by heating it can be returned to its original memorized shape and brought into close contact with the groove, making it possible to efficiently attach the retaining ring.

[Brief explanation of drawings]

Figure 1 is a side view of the shaft fitted with a split retaining ring. FIGS. 2 and 3 are front and side views of the split retaining ring, respectively. FIG. 4 is a cross-sectional view showing a heat treatment jig for restraining multiple split retaining rings from the inner and outer diameter portions. 1"-split retaining ring, 2 shaft. 3 split part, 4° annular groove. 5" round bar core, 6 heat treatment jig. 7 bottom plate, 8 cylindrical body. 9 cap, 10 spacer. 11 Taper guide part

Claims (1)

[Claims] A thin wire with a circular or rectangular cross section made of a shape memory alloy of nickel-titanium alloy or copper-zinc-aluminum alloy has an inner diameter equal to or slightly smaller than the outer diameter of the shaft and an effective inner diameter equal to the circumferential length of the annular groove of the shaft. Form a split retaining ring with a circumferential length, cool it below its unique Ms point to make it deformable, reduce the diameter to an inner diameter equal to the diameter of the annular groove of the shaft, and form a plurality of split retaining rings. At the same time, the inner diameter part and the outer diameter part are restrained in this reduced diameter state, heated and maintained at a temperature of 300 to 500 °C above the Af point, and after the split retaining ring memorizes its shape, it is cooled, and this shape memory heat treatment is performed. The received split-shaped retaining ring is cooled to a temperature below its unique Ms point to make it deformable, and is fitted into the annular groove of the shaft, and Af
A method for producing a shaft with a retaining ring, characterized in that the retaining ring is heated above a point to return the retaining ring to its memorized shape and firmly fitted into an annular groove.