JPH0440092B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a method of molding a collapsible spacer in which a part of a cylindrical material body is bulged with an elastic deformable portion having a diameter different from that of the body. The present invention relates to a method and an apparatus for the same.

(Prior art) A collapsible spacer used in the final reduction gear of an automobile is made by cutting a steel pipe to a predetermined length to form a cylindrical material, and a part of this cylindrical material has a bead that bulges out in an annular shape. The cylindrical material is formed to have predetermined spring characteristics by forming an elastically deformable portion. In this way, when a steel cylindrical material in which a bead-shaped elastic deformation part is formed is used as a spring material, a characteristic is obtained in which strain increases when stress exceeds a predetermined value.

Conventionally, in order to form a collapsible spacer having such an elastically deformable portion, as disclosed in Japanese Utility Model Application Publication No. 57-141822, a mold having an inner circumferential surface corresponding to the outer circumferential shape of a cylindrical material is used. After the material is placed on the material, an elastic deformation portion is formed by applying hydraulic pressure from the inside of the material, pressing urethane rubber, or pressing a roller.

However, when the collapsible spacer is manufactured using such a conventional forming method, it is necessary to adjust the predetermined spring characteristics by the amount of plastic processing. The adjustment range was narrow, and when mass-produced, there were problems in that specific spring characteristics could not be maintained due to variations in material dimensions and mechanical properties.

(Object of the Invention) The present invention focuses on the above-mentioned problems of the prior art, and aims to make it possible to quickly mold a cylindrical material having a desired spring characteristic in one process in a single process. .

(Structure of the Invention) To achieve the above object, the present invention provides a method for forming a collapsible spacer having a cylindrical body and an elastically deformable portion having a diameter different from the diameter of the cylindrical body. While the radial deformation of both ends of the cylindrical material is restrained, an axial compressive force is applied to the cylindrical material while heating the cylindrical material to a hot temperature, thereby causing the cylindrical material to have the elasticity. The method for forming a collapsible spacer includes forming the elastic deformation portion by cooling and annealing the cylindrical material after forming the deformation portion, and further comprising forming a cylindrical body and a diameter different from that of the body. An apparatus for forming a collapsible spacer having an elastically deformable portion having a first processing die that fits with one end of a cylindrical material to restrain radial deformation of the one end; a second processing die that fits with the other end and restrains radial deformation of the other end; and a pressurizing means for applying compressive force to the cylindrical material by moving the second processing die relatively close to each other; and a heating means for heating the cylindrical material to a hot temperature is provided in the processing mold, and a compressive force is applied in the axial direction while heating the cylindrical material to form an elastic deformation part in the cylindrical material. A collapsible spacer forming apparatus is characterized in that the cylindrical material is annealed at the same time.

(Example) Hereinafter, the present invention will be explained based on the drawings. 1st
The figure shows a collapsible spacer molding apparatus according to an embodiment of the present invention, in which a fixing jig 2 is attached to a molding apparatus main body 1, and a rod 4 of an air cylinder 3 is attached to the molding apparatus main body 1. A movable jig 4 is attached to the tip. The fixed jig 2 is provided with a first processing die 5, and the movable jig 4 is provided with a second processing die 6. The second processing die 6 is moved up and down by the air cylinder 3 to form the first processing die 5. Processing type 5
It is possible to move close to the enemy. In the illustrated embodiment, the lower first processing die 5 is fixed and the upper second processing die 6 is moved, but conversely, the lower first processing die 5 is moved and the upper second processing die 6 is moved. The mold 6 may be fixed.

The details of the first processing die 5 and the second processing die 6 shown in FIG. 1 are as shown in FIG. A groove 7 into which the cylindrical material W fits is formed, and a groove 8 into which the other end of the cylindrical material W fits is formed in the second mold 6. Further, a stopper 9 is fixed to the center of the first processing die 5 for regulating the position at which the second processing die 6 approaches the first processing die 5 closest.

Each of the processing molds 5 and 6 is made of a conductive electrode material, and, for example, a positive terminal of a transformer 10 shown in FIG. The negative terminal is electrically connected to the second processing mold 6 via a cable 12.
The stopper 9 shown in FIGS. 1 and 2 is made of an insulating material.

Next, a method for forming a bead, that is, an elastic deformation part B, in a cylinder W using the forming apparatus shown in FIGS. 1 and 2 will be explained. First, a cylinder formed by cutting a steel pipe into a predetermined length One end of W is fitted into the groove 7 of the first processing die 5 forming one electrode. Under this condition, the air cylinder 3 is operated to move the second processing die 6 forming the other electrode closer to the first processing die 1, and the other end of the cylindrical body W is inserted into the groove 8 of the second processing die. Fit the parts together. This state is shown in the left half of FIG. 2, and both ends of the cylindrical body W are restrained from being deformed in the radial direction by the grooves 7 and 8, respectively.

Further, under this condition, electricity is applied to the cylinder W from the transformer 10 via the cables 11 and 12 through the respective working molds 5 and 6, which are electrodes. This energization time is controlled by a timer built into the molding apparatus main body 1. By supplying electricity to the cylindrical body W, the cylindrical body W is heated by Joule heat and reaches a predetermined temperature, and at the same time, the cylindrical body W is moved in the axial direction by the second mold 6 due to the pressing force based on the operation of the air cylinder 3. A compressive force will be added to the In this way, the cylinder W
By applying compressive force in the axial direction while heating, a bead B is formed in the center of the cylinder W.
The state in which the bead B is formed is shown in the right half of FIG. 2. After forming the elastically deformable portion, that is, the bead B, in this way, the cylindrical material W including the elastically deformable portion B is air-cooled and annealed, as will be described later.

FIG. 3 shows a processing mold 5 according to another embodiment of the present invention.
6, in this molding apparatus, one end of the cylinder W is fitted into the groove 7 of the first processing die 5, and the other end is fitted into the groove 8 of the second processing die 6. In this state, the coil 13 is attached to the second processing die 6 so as to surround the axial center portion of the cylindrical body W. This coil 13 is supplied with a high frequency current from a power source (not shown), and serves as a heating means for heating the cylindrical body W by the high frequency induced current.

FIG. 4 is a diagram showing a molding apparatus according to another embodiment of the present invention, in which a torch 14 that emits a flame such as an oxyacetylene flame is attached to the second processing mold 6 by a bracket (not shown), and thereby It serves as a heating means.

5 and 6 are diagrams respectively showing forming apparatuses according to still other embodiments of the present invention. belongs to. Since the size of the cylinder W is long, the first processing mold 5 is divided into two processing mold structures 5a and 5b so that the cylinder W can be easily attached to the first processing mold 5. The respective machining die structures 5a, 5b are movable toward and away from each other, and each of the machining die structures 5a, 5b has one end portion of the cylindrical body W restrained to prevent it from deforming in the radial direction. A recess 15 is formed. Similarly, a recess 16 is formed in the second processing mold 5 to restrain the other end of the cylindrical body W and suppress deformation in the radial direction. The molding device shown in FIG.
The working molds 6 each serve as an electrode and are configured to heat the cylindrical body W by Joule heat. The molding apparatus shown in FIG. 6 is configured to heat the cylindrical body W by a high frequency induced current applied to the coil 13. Note that in the molding apparatus shown in FIGS. 5 and 6, the torch 14 is also used as shown in FIG.
It is also possible to heat the cylindrical body W with flame.

In the bead forming method and apparatus described above,
Since compressive force in the axial direction is applied to the cylindrical body W while heating the cylindrical body W by the heating means, the cylindrical body W is subjected to hot plastic working, and the cylindrical body W is plastically worked with a smaller compressive force. This makes it possible to form the bead B with a small compressive force. Moreover,
By subjecting the cylindrical body W heated to a hot temperature to a predetermined process such as atmospheric cooling, that is, annealing,
The heating means for plastic working can also be used as a heat source for heat treatment. That is, in order to perform plastic working with a small compressive force, the present invention uses a heat source that heats to hot temperature as a heat source for annealing treatment, and thereby,
The elastically deformable portion B can have desired spring characteristics.

Therefore, when setting the spring force to a specific value in response to the axial load applied to the cylindrical body W by the elastic deformation portion (bead) B formed in the cylindrical material W as in the above-mentioned collapsible spacer, is the spring characteristic against the axial load applied to the cylinder W by adjusting the amount of annealing by applying current to the cylinder W or the time of irradiating the flame and heat treatment after plastic working, and adjusting the amount of plastic deformation. can be adjusted over a much wider range than in the conventional molding method using only plastic deformation, and desired characteristics can be easily obtained.

The basic principle of the present invention is to plastically work the cylindrical material while it is heated to a hot temperature, thereby making it possible to adjust the spring characteristics within a wide range. Figure 7 is a graph showing experimental data showing how wide a range of spring characteristics can be obtained in the present invention. indicates the value of the spring force of the collapsible spacer obtained.

In the same graph, the white circles indicate the case where the material is plastically worked in a cold state without heating. In this case, only a product with spring characteristics of a certain value can be obtained, but in the case of the present invention, It is clear that by heating the material in a hot state and arbitrarily changing the energization time, it is possible to obtain a collapsible spacer having desired characteristics.

(Effects of the Invention) As described above, according to the present invention, one end of the cylindrical material is fitted into the first processing die, the other end of the cylindrical material is fitted into the second processing die, and the cylindrical material is made into a cylinder. The radial deformation of both ends of the cylindrical material is restrained, and while the cylindrical body is heated by a heating means, the two processing dies are brought relatively close to each other to apply an axial compressive force to the cylindrical material. Therefore, it is possible to perform hot plastic working and subsequent cooling annealing on the cylindrical body in one step, and it is possible to easily and quickly form an elastically deformed portion in the cylindrical material.

[Brief explanation of drawings]

FIG. 1 is a front view showing a collapsible spacer molding apparatus according to an embodiment of the present invention, and FIG.
3 to 6 are cross-sectional views showing parts of the processing die before and after processing of the apparatus shown in the figure, and FIGS. 3 to 6 are respectively sectional views of the collapsible spacer forming apparatus before and after processing of the apparatus for forming collapsible spacers according to other embodiments of the present invention. FIG. 7 is a cross-sectional view showing a portion of the processing mold in FIG. 7, and FIG. 7 is a graph showing the relationship between the heating time of the material by resistance heating and the spring characteristics of the obtained material. W... Cylindrical material (cylindrical body), B... Elastic deformation part (bead), 1... Molding device main body, 5... First processing die, 6... Second processing die, 7, 8... Groove , 9...stoppa.

Claims (1)

[Claims] 1. A method for forming a collapsible spacer having a cylindrical body and an elastically deformable portion having a diameter different from the diameter of the body, the method comprising radially deforming both ends of the cylindrical material. After forming the elastic deformation portion in the cylindrical material by applying an axial compressive force to the cylindrical material while heating the cylindrical material to a hot temperature in a restrained state, the cylindrical material is A method for forming a collapsible spacer, wherein the elastically deformed portion is formed by cooling and annealing a shaped material. 2. The method for molding a collapsible spacer according to claim 1, wherein the cylindrical material is heated by Joule heat generated when the cylindrical material is energized. 3. The method for forming a collapsible spacer according to claim 1, characterized in that a high-frequency current is passed through a coil surrounding the cylindrical material, and the cylindrical material is heated by the high-frequency induced current. . 4. The method for forming a collapsible spacer according to claim 1, wherein the cylindrical material is heated with a flame such as an oxyacetylene flame. 5 A device for forming a collapsible spacer having a cylindrical body and an elastic deformable portion having a diameter different from the diameter of the body, which fits into one end of a cylindrical material and deforms the one end in the radial direction. A first processing mold that restrains the cylindrical material and a second processing mold that fits with the other end of the cylindrical material and restrains radial deformation of the other end are moved relatively close to each other to A pressurizing means for applying a compressive force is provided in the processing mold, a heating means for heating the cylindrical material to a hot temperature is provided in the processing mold, and a compressive force is applied in the axial direction while heating the cylindrical material. A collapsible spacer molding apparatus characterized in that an elastic deformation portion is formed in the cylindrical material and the cylindrical material is annealed. 6. The heating means configured by using the first processing mold and the second processing mold as electrodes, respectively, and heating the cylindrical material with Joule heat by applying electricity to the cylindrical material through these processing molds. A collapsible spacer molding apparatus according to claim 5. 7. Claim 5, characterized in that the heating means is constructed by attaching to the processing mold a coil that surrounds the cylindrical material and is energized with a high-frequency current.
The collapsible spacer molding apparatus described in 2. 8. The collapsible spacer forming apparatus according to claim 5, wherein a flame of oxyacetylene or the like is used as the heating means.