JP4939458B2 - Drilling method - Google Patents

Description

  The present invention relates to a hole machining method for forming a relatively thin and bent hole in a metal.

  An elongated curved hole whose longitudinal direction is substantially along the outer peripheral surface is formed at a position shifted from the central axis toward the outer periphery in the substantially cylindrical metal member whose one end is gradually tapered. There is a case. Examples of such a hole include a fuel supply hole that is formed inside a body of an injector in a fuel injection device such as an automobile and guides fuel to an injection nozzle (see Patent Documents 1 and 2). Drilling is generally used to form a hole in a metal, but when forming an elongated hole, a pilot hole with a diameter slightly larger than the desired diameter is formed to a certain length, and then the back is formed. A method is adopted in which the length of the narrow hole is reduced as much as possible by processing with a thin diameter drill. In order to obtain a bent hole, a hole is formed from one end side to the middle, and then the angle is changed from the other end side to form a hole.

JP 2006-226241 A JP 2007-270743 A

  However, in such a method, since the lower hole is formed, there is a complaint that the diameter of the hole cannot be made constant at a desired diameter over the entire length. Further, in order to form the pilot hole, it is necessary to ensure a corresponding thickness on the outer peripheral side of the pilot hole, so that the outer diameter of the entire member becomes larger than necessary. Increasing the diameter of the member by securing the wall thickness is remarkable from the viewpoint of pressure resistance when it is like the above-mentioned injector, for example, and the space around the injector is restricted and the degree of freedom in design is reduced. Cause problems such as Furthermore, there is a drawback that productivity is inferior because a plurality of drilling steps are performed.

  Therefore, according to the present invention, it is possible to achieve a long and narrow bent hole with a constant diameter over a whole length by a relatively simple method, and to improve the degree of freedom of design and productivity around the member. The purpose is to provide.

  The hole drilling method of the present invention includes a primary hole forming step of forming a linear primary hole parallel to the central axis at a position shifted from the central axis of the cylindrical metal material toward the outer periphery, and linear to the primary hole. A linear metal insertion process for inserting metal and maintaining the insertion state, and swaging the metal material, the metal material is placed in a cylindrical portion having a smaller diameter than the original outer diameter, and the cylindrical portion. An outer peripheral surface of the formed processing member is formed into a processed member having a reduced diameter portion where the outer diameter is continuously reduced, and further, the primary hole is reduced by this, and together with the linear metal, the axis of the outer peripheral surface of the formed processing member It is characterized by comprising a swaging step of bending along a direction to deform into a bent hole, and a linear metal drawing step of drawing a linear metal from the bent hole to obtain a processed member in which the bent hole is formed.

  According to the present invention, since a bent hole is obtained by pulling out the linear metal after swaging the metal material into which the linear metal is inserted, the bent hole can be formed more easily than drilling, Improves. Further, by using a linear metal having a uniform thickness, it is easy to form the bent hole with a constant diameter over the entire length. Furthermore, since it is not necessary to form a pilot hole unlike drilling, the member after processing can be made compact, and the degree of freedom of design around the member can be improved.

  In the present invention, in the linear metal insertion step, at least one of the inner peripheral surface of the primary hole and the outer peripheral surface of the linear metal is lubricated before inserting the linear metal into the primary hole of the metal material. Is a preferred form. If this form is taken, the effect that it becomes easy to draw | extract a linear metal from a process member at a linear metal extraction process will be acquired. Examples of the lubricating treatment include application of lubricating oil and film formation with a solid lubricant such as molybdenum disulfide and graphite. When a film is formed with a solid lubricant, the solid lubricant is collapsed when the linear metal is pulled out, and thereby a gap is formed between the linear metal and the inner surface of the bent hole, which makes it easier to pull out. Improvement can be expected.

  In order to make it easier to pull out the linear metal, a means that the metal material is made of a material having a higher coefficient of thermal expansion than the linear metal is also effective. In this case, in the linear metal drawing process, the linear metal is drawn in a state where the processed member in which the linear metal is inserted is heated. Since the degree of expansion of the metal material (processed member) is larger, the inner diameter of the bent hole into which the linear metal is inserted is slightly larger than the outer diameter of the linear metal, causing slack, and pulling out the linear metal It becomes easy.

  According to the present invention, it is possible to achieve a long and narrow bent hole with a constant diameter over the entire length by a relatively simple method, and the effect of improving the degree of freedom of design and productivity around the member can be achieved. Play.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[1] Primary hole forming step 1A in FIG. 1 shows a cylindrical metal material that is processed into a predetermined processed member in which a bent hole is formed by the hole processing method of one embodiment. Yes. In the hole drilling method according to one embodiment, first, as shown in FIG. 1, linear primary holes 11 parallel to the center axis O are formed at positions shifted from the center axis O of the metal material 1 </ b> A toward the outer periphery. The diameter of the primary hole 11 is uniform and larger than the diameter of the bent hole to be finally obtained. The primary hole 11 can be formed by means such as piercing (punching) or drilling. The material of the metal material 1A is appropriately selected from, for example, a low alloy steel (for example, chromium molybdenum steel such as SCM415) that is general as a metal material for general machine parts and automobile parts, and various steels such as stainless steel.

[2] Wire Insertion Step After the primary hole 11 is formed in the metal material 1A, as shown in FIG. 2A, the wire having the same outer diameter as the diameter of the bent hole to be obtained in the primary hole 11 of the metal material 1A ( (Linear metal) 21 is inserted. As the wire 21, for example, a general wire such as a stainless steel wire or a piano wire is used. A wire 21 that is sufficiently longer than the length of the primary hole 11 of the metal material 1A is used, and the wire 21 is subjected to the next step in a state where both ends protrude from the primary hole 11. In addition, as a diameter dimension of the primary hole 11 and the piano wire, the primary hole 11 is about φ5 to 10 mm, and the wire 21 is about φ2 to 4 mm.

[3] Swaging process The metal material 1A in which the wire 21 is inserted into the primary hole 11 is subjected to swaging with a rotary swaging apparatus 30 as shown in FIGS. 2 (b) to 2 (c). 2 (d) and the processed member 1B shown in FIG. 4 are formed. As shown in FIG. 3, the swaging apparatus 30 is a metal material inserted inside each die 31 by repeatedly reciprocating in the radial direction while rotating a plurality of dies 31 arranged in an annular shape in the circumferential direction. By applying impact pressure to 1A, the diameter is reduced and the length in the axial direction is extended. The metal material 1 </ b> A is supported by the guide rod 32, and is shaped into a shape whose outer shape follows the inner surface of the die 31 while being pushed in one direction in the die 31 by the pusher 33.

  In the swaging process in this case, as a first stage, as shown in FIG. 2 (b), the metal material 1A is reduced in diameter to a constant outer diameter to form the whole into a cylindrical shape, and in the next second stage, As shown in FIG. 2 (c), one end side is formed into a tapered shape whose outer diameter gradually decreases. By completing the second stage, a target processed member 1B shown in FIG. 2D is obtained. The processed member 1B has a shape having a cylindrical portion 2 having a diameter smaller than the outer diameter of the original metal material 1A and a tapered portion 3 whose outer diameter gradually decreases from one end of the cylindrical portion 2. The primary hole 11 is reduced in diameter by swaging until the inner peripheral surface is in close contact with the wire 21. The primary hole 11 is bent along the axial direction of the outer peripheral surface of the processed member 1 </ b> B together with the wire 21, and is formed in the bent hole 4.

[4] Wire Pulling Step After the processed member 1B is formed into a target shape, the wire 21 is then pulled out from the bent hole 4. Thereby, the processed member 1B in which the bent hole 4 is formed is obtained. The bent hole 4 is formed to have a constant diameter that is equal to the outer diameter of the wire 21.

  As described above, the processed member 1B having a shape in which the cylindrical portion 2 and the tapered portion 3 are continuous is formed, and is bent along the axial direction of the outer peripheral surface at a position shifted from the central axis in the processed member 1B toward the outer periphery. A bent hole 4 having a uniform diameter is formed. The hole drilling method of the present embodiment for forming the bent hole 4 in this way is to obtain the bent hole 4 by drawing the wire 21 after swaging the metal material 1A into which the wire 21 is inserted. The bent hole 4 can be formed more easily than drilling. Further, by using the wire 21 having a uniform thickness, it is easily achieved that the bent hole 4 is formed with a constant diameter over the entire length.

  Further, since the pilot hole is formed at the time of drilling, it is necessary to increase the thickness around the bent hole, but this is not necessary in the present embodiment. For this reason, the processing member 1B can be made compact, and when the processing member 1B is mounted on a predetermined device, the degree of freedom in designing the surroundings can be improved.

  In addition, in order to make it easy to pull out the wire 21 from the processed member 1B in the wire pulling process, in the wire inserting process, one or both of the inner peripheral surface of the primary hole 11 and the outer peripheral surface of the wire 21 are lubricated. It is a preferable method to insert the wire 21 into the primary hole 11 after applying the above. As the lubrication treatment, it is easy to apply a lubricating oil such as grease. In addition, the method of forming a film with a solid lubricant such as molybdenum disulfide or graphite causes the solid lubricant to collapse when the wire 21 is pulled out, so that a gap is formed between the wire 21 and the inner surface of the bent hole 4. Further improvement in the ease of pulling out can be expected.

  In order to easily pull out the wire 21 from the processed member 1B, it is also effective to use a material having a higher thermal expansion coefficient for the metal material 1A than for the wire 21. In this case, in the wire drawing process, the wire 21 is drawn while the processed member 1B in which the wire 21 is inserted is heated. Then, since the metal material 1A (working member 1B) has a higher degree of expansion, the inner diameter of the bent hole 4 into which the wire 21 is inserted is slightly larger than the outer diameter of the wire 21, causing slackness. It becomes easy to pull out. As an example of the material, for example, when the metal material 1A is the above-described SCM415, a steel wire having a lower coefficient of thermal expansion is selected as the wire 21. Further, when aluminum is used for the metal material 1A or austenitic stainless steel such as SUS303 is used, since these have a relatively high coefficient of thermal expansion, a piano wire can be used for the wire 21.

  INDUSTRIAL APPLICABILITY The present invention can be used when manufacturing a body of an injector in a fuel injection device installed in an engine such as an automobile.

It is (a) sectional side view of metal raw material 1A processed with the hole processing method which concerns on one Embodiment of this invention, (b) It is a front view. It is a sectional side view which shows the process of the hole processing method which concerns on one Embodiment in order of (a)-(d). It is sectional drawing of a swaging processing apparatus. It is a sectional side view of the process member 1B obtained by the hole processing method which concerns on one Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1A ... Metal raw material 1B ... Processing member 2 ... Cylindrical part 3 ... Tapered part (reduced diameter part)
4 ... Bending hole 11 ... Primary hole 21 ... Wire (linear metal)
O ... Center axis

Claims (3)

A primary hole forming step of forming a linear primary hole parallel to the central axis at a position shifted from the central axis of the cylindrical metal material toward the outer periphery;
A linear metal insertion step of inserting a linear metal into the primary hole and holding the inserted state;
By subjecting the metal material to swaging processing, the metal material is processed into a cylindrical portion having a smaller diameter than the original outer diameter, and a reduced diameter portion whose outer diameter is continuously reduced to the cylindrical portion. A swaging step in which the diameter of the primary hole is further reduced, and along with the linear metal, the step is bent along the axial direction of the outer peripheral surface of the processed member to be transformed into a bent hole; ,
A drilling method comprising: a linear metal drawing step of drawing the linear metal from the bent hole to obtain a processed member in which the bent hole is formed.   In the linear metal insertion step, before inserting the linear metal into the primary hole of the metal material, at least one of the inner peripheral surface of the primary hole and the outer peripheral surface of the linear metal is lubricated. The drilling method according to claim 1, wherein:   The metal material and the linear metal are made of metals having different thermal expansion coefficients, and the thermal expansion coefficient of the metal material is larger than that of the linear metal. Hole drilling method.

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