JPH01317649A - Production of core base body for injector - Google Patents

Abstract

PURPOSE:To produce the core base body with good accuracy by disposing an insert having a hole of the diameter smaller than the diameter of a hole for sleeve insertion to the other end side of a stock with respect to a boring punch and boring the hole for sleeve insertion by the boring punch just before the hole is completely bored throughout the stock, then removing the insert and boring the hole completely with the punch. CONSTITUTION:Both end faces of the bar-shaped stock W consisting of an electromagnetic free-cutting stainless steel contg. Cr are shaved. The stock W is then subjected to film forming after cleaning and to molding by cold forging by which the semi- finished molding X having a collar part 11 and having a large-diameter filter mounting hole 12 at one end and a shallow small hole 13 at the other end is obtd. This molding is annealed to relieve the residual stress of the collar part 11 and to lower the hardness thereof. The semi-finished product X is subjected to extrusion boring of the hole 14 for sleeve insertion. The product X is upset in a die 18 by a movable punch 15 so that the end face 13 faces the insert 19. The hole 14 for sleeve insertion is bored by the boring punch 16. A part 22 of the material is pushed into the hole 20 of the insert 19 to complete the boring. The master punch is inserted therein to improve the accuracy. The performance of the injector is improved in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for manufacturing a core substrate used in an injector.

[Prior Art] As shown in FIG. 5, an injector has a core 32 installed inside a main body 31, a coil 33 wound around the core 32, and a sleeve 34 and a valve assembly 35 provided inside the core 32. A spring 36 is stretched between the coil 33
The core 32 is energized by the current flowing through the valve assembly 35, and the valve assembly 35 is operated against the spring 36 to start or stop the flow of fuel. Therefore, the operation of the valve assembly 35, which determines the amount of fuel to be injected, depends on the strength of the spring 36, and the setting of the strength of the spring 36 greatly influences the performance of the injector. To set the strength of the spring 36 to the required value, adjust the position of the sleeve 34 and attach it to the core 32, but the most important thing here is to set the strength of the 47S to the required value. 3 Sleeve 34 that should have been completed
Installation is dependent on whether the positional accuracy is as specified.

The core 32 has conventionally been manufactured by cutting the inner and outer diameters of a core material obtained by cold forging an electromagnetic free-cutting stainless steel bar material using a machine tool such as an automatic lathe.

[Problem to be Solved by the Invention] However, since the core 32 is formed by cutting as described above, it is difficult to manufacture the small diameter and long sleeve insertion hole 38 with manufacturing precision including straightness, and the spiral shape formed by turning is difficult to achieve. This results in scratches, making it difficult to improve the accuracy of surface roughness.

The above-mentioned poor accuracy results in variations in the gap between the core 32 and the sleeve 34, and if this gap is large, the sleeve 34 will be inclined with respect to the core 32 during the above-mentioned mating 37, which will change the compression margin of the spring 36.

This has an adverse effect on the performance of the injector, and conversely, if the gap is small, the surface roughness due to the spiral scratches and the fallout of the scratches will adversely affect the sleeve against the core 32 at the time of the four missing parts 37. This obstructs the smooth movement of the sleeve 34 and makes it difficult to secure the sleeve 34 in a predetermined position, which changes the compression margin of the spring 36 as described above and also causes injection clogging due to the fallen part of the scratch. This had a negative effect on the performance of the injector.

SUMMARY OF THE INVENTION Therefore, the present invention aims to solve the above-mentioned problems of the prior art by easily manufacturing a core base having a sleeve insertion hole with high precision and being less likely to cause scratches.

[Means for Solving the Problems] That is, the present invention cold-forges a rod-shaped material cut to a required length, and has a large diameter filter mounting hole at one end and a small diameter sleeve insertion hole at the other end. In the method of manufacturing a core base for an injector having a flange on the outer periphery, when forming the sleeve insertion hole, an insert having a hole slightly smaller in diameter than the sleeve insertion hole is inserted into the rod-shaped material while facing a punch. For an injector, characterized in that a hole for inserting the sleeve is drilled with a hole punch until it is just before penetration in the state where the insert is disposed at the other end, and then the hole for inserting the sleeve is penetrated with a punch while the insert is in the instruction manual state. The first invention is a method for manufacturing a core base body, and a rod-shaped material cut to a required length is cold-forged to have a large diameter filter mounting hole at one end and a small diameter sleeve insertion hole at the other end. In the method for manufacturing a core base for an injector having a flange on the outer periphery, prior to the cold forging, both end faces of the rod-shaped material are processed by grinding, and when forming the sleeve insertion hole, the sleeve insertion hole is formed. An insert having a hole slightly smaller in diameter than the insert is placed on the other end of the rod-shaped material, facing the punch, and a hole for inserting the sleeve is drilled with the punch until just before the insert is penetrated. This invention also includes a second aspect of the present invention, which is a method of manufacturing a core base for an injector, characterized in that the sleeve insertion hole is penetrated at the bottom with a punch.

[Function] In this method, when forming the sleeve insertion hole, when the sleeve insertion hole is drilled with the hole punch and the depth of the hole becomes deeper, part of the material pushed by the hole punch flows into the small hole of the insert, reducing the load on the punch, and the insert prevents the sleeve insertion hole from breaking until just before it is penetrated.

In addition, due to this drilling just before penetration, the bottom of the sleeve insertion hole during drilling becomes thinner and harder.
Punching of the bottom of the sleeve insertion hole in the next step with a punch is performed smoothly.

In the second invention, further, prior to cold forging, both ends of the rod-shaped material are end-face processed by cutting, so that the fracture layer at the time of cutting is removed from both end surfaces of the rod-shaped material, and the surface of the sleeve insertion hole is removed. Improves roughness accuracy.

[Embodiment] Next, an embodiment of the present invention will be described with reference to FIGS. 1 to 4.

In this example, a coil material of electromagnetic free-cutting stainless steel containing about 13% chromium is used as the material, and the coil material is cut to the required length with a transfer hoer for cold forging to form a rod-shaped material W.
(Fig. 1a), turn the material W over and swaddle it (Fig. 1b), then turn it over and upset it to shave one end surface 1 (Fig. 1c), and then turn it over and swathe it (Fig. 1c). The other end face 2 is shaved thoroughly (Fig. 1d).

This shaving process will be explained in more detail with reference to Figures 3 and 4. In the figures, 3 is a die, 4 is a knockout pin, and 5 is a shaving tool. It is attached to a shaving device M7 that reciprocates in the direction.

However, when the material W is placed on the die 3.

The shaving device 7 goes forward and the cutting tool 5 shaves the end face of the material W slightly protruding from the die 3,
When the cutting tool 5 returns to the shaving device 7, the material W is pushed out by the knockout pins 4.

In this way, both end surfaces 1 and 2 of the material W are shaved, but instead of this shaving, it is also possible to simultaneously polish both end surfaces 1 and 2 of the material W using a polishing machine exclusively for both ends. (Fig. 1e) s By processing both end faces 1 and 2.

On both end faces 1.2, the fracture layer during cutting is removed to improve the accuracy of the surface roughness, and the accuracy of the surface roughness of the hole surface during drilling in the subsequent cold forging process is improved. This prevents the peeling phenomenon of the hole surface.

Next, this material W is coated after cleaning and formed by cold forging in a transfer parts homer (Fig. 1 f,
Steps g, h, i, and j) are performed in sequence, and the flange 11 is made on the outside, the hole 12 for attaching a large diameter filter is made on one end, and the shallow small hole 1 is made on the other end.
An intermediate molded product X having 3 is obtained.

In this cold forging, the intermediate molded product X leaves a very large residual stress in the flange portion 11, so it is then annealed to remove the stress and reduce the hardness.

Next, this intermediate molded product X is extruded to form a sleeve insertion hole 14 (1 in FIG. 1).

This process will be explained in detail in Figure 2. In the figure, 15.15" is a movable punch, 16 is a drilling punch, 1
7.17" is punch knockout color, 18.18"
is a die, 19 is an insert having a hole 20,
The hole 20 is provided in the die 18 opposite to the punch, and the diameter of the hole 20 is slightly smaller than that of the punch 16. 21.
21' is a knockout collar, 25 is a second insert having a hole 24, and 26 is a punch.

The intermediate molded product The sleeve insertion hole 14 is drilled until just before it penetrates (FIG. 2b). As a result of this drilling, the part 22 of the material of the intermediate molded product X pressed by the punch 16 is pushed out into the hole 20 of the insert 19. come. in this case.

At the early stage of drilling, the material of the intermediate molded product X is pushed out to the rear of the punch 16 as the cross section decreases, and at the middle stage of drilling, the material of the flange 1
1 makes the backward extrusion difficult, but insert 1
A portion 22 of the material is extruded into the hole 20 of the insert 19 by forward extrusion, and at this time, since the hole 20 of the insert 19 is slightly smaller than the diameter of the punch 16, the sleeve insertion hole 14 that is being punched is prevented from breaking. The sleeve insertion hole 14 is drilled until the bottom thickness 23 is as thin as possible. Further, since the portion 22 of the material is extruded forward, the load applied to the punch 16 does not become excessive due to an increase in the depth of the hole, and the punch 16 is unlikely to break. After the drilling is completed, the intermediate molded product X is pushed out by the knockout collar 21 until the end of the portion 22 of the material is positioned outward from the tip surface 28 of the die 18. In this case, the knockout collar 21 is pulled back by a return spring (not shown) immediately after the intermediate molded product X is pushed.

If the strength of the bottom thickness 23 is strong enough to withstand the force of extruding the intermediate molded product X from the die 18, a second
There is no problem in using the knockout bin 29 shown by the imaginary line in the figure.

Next, with the second insert 25 having a hole 24 slightly larger than the sleeve insertion hole 14 in contact with the end surface 30 of the intermediate molded product X, the bottom 27 of the sleeve insertion hole 14 is punched out with a punch 26 (the 2C), in this case, since the hardness of the bottom 27 of the hole has been increased by the previous process, it is easy to punch out, and almost no cracks are observed.

Next, the step of the sleeve insertion hole 14 is formed by the punching described above (FIG. 1m).

Next, the sleeve insertion hole 14 and the filter mounting hole 1
2 to improve accuracy by passing it through a master punch (Fig. 1 m)
).

Next, a master punch is further passed through the sleeve insertion hole 14 and the filter attachment hole 12, and the flange portion 11 is formed to obtain the core base body Y of the product.

In the core base body Y obtained in this way, the fracture layer at the time of cutting has been removed by shaving or polishing both end faces 1.2 of the material W, so that it can be used for inserting a sleeve. The accuracy of the surface roughness of the hole surface of the hole 14 has been improved, and the small diameter and long sleeve insertion hole 14 is made by cold forging, which reduces the gap between it and the sleeve 34 that was formed with the conventional technology. As a result, the inclination of the sleeve 34 at the insertion 37 and the change in the spring 36 load were reduced, and the performance of the injector was improved.Also, in manufacturing, the sleeve insertion hole 14 and the filter mounting hole 12 are formed by cold forging, so they can be manufactured in a short time.

[Effects of the Invention] As described above, according to the present invention, it is possible to easily manufacture a core base material in which the sleeve insertion hole has high precision and is hard to cause scratches.
Therefore, it is possible to ensure smooth movement between the sleeve insertion hole and the sleeve when it is assembled into the injector, and as a result, the spring load of the injector can be maintained as desired and the performance of the injector can be improved. In the second invention,
Furthermore, since the fracture layer during cutting is removed by end face processing, the accuracy of the surface roughness of the sleeve insertion hole is further improved, and the phenomenon of peeling of the hole surface of the sleeve insertion hole from the fracture layer is prevented. do.

[Brief explanation of the drawing]

Figures 1 a to 0 are side sectional views of a workpiece shown in the order of steps in an embodiment of the present invention, and Figures 2 a to C are longitudinal sectional views showing a part of the cold forging process in the same example in order of steps. , FIG. 3 is a longitudinal sectional view of the shaving process of the same example, FIG. 4 is a right side view of FIG. 3, and FIG. 5 is an explanatory longitudinal sectional view of the injector. l... end face, 2... end face, 11... flange, 12...
... Filter mounting hole, 14... Sleeve insertion hole,
16...Drilling punch, 19...Insert, 20.
... Hole, 26... Punch, W... Material, Y... Core base Patent applicant Myamar Co., Ltd. Figure 1 tz 4 C k no m
le ri

Claims (1)

[Claims] 1. A rod-shaped material cut to a required length is cold-forged to have a large-diameter filter mounting hole at one end, a small-diameter sleeve insertion hole at the other end, and a flange on the outer periphery. In the method for manufacturing a core base for an injector, when forming the sleeve insertion hole, an insert having a hole slightly smaller in diameter than the sleeve insertion hole is arranged at the other end of the rod-shaped material facing the punch. A method for producing a core base for an injector, comprising: drilling a sleeve insertion hole with a punch until just before penetration under the condition, and then piercing the sleeve insertion hole with a punch while the insert is being removed. 2. A core base for an injector is manufactured by cold forging a rod-shaped material cut to the required length to have a large-diameter filter mounting hole at one end, a small-diameter sleeve insertion hole at the other end, and a flange on the outer periphery. In the method, prior to the cold forging, both end faces of the rod-shaped material are machined by grinding, and when forming the sleeve insertion hole, an insert having a hole slightly smaller in diameter than the sleeve insertion hole is formed using a drilling punch. A hole for inserting the sleeve is punched in the other end of the rod-shaped material facing the inserted state with a hole punch until just before penetration, and then, with the insert removed, the hole for inserting the sleeve is penetrated with a punch. A method for manufacturing a core substrate for an injector, characterized in that: