JP2013006189A - Device and method for manufacturing hollow rack bar - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a hollow rack bar without reducing productivity, while securing sufficiently the tooth width and tooth height for a tooth part.SOLUTION: A device includes: a die 20 that has a tooth mold 24 and holds a steel tube 1A opened at both ends and having a processing wall 5 on which racks 4 are formed by the tooth mold 24; a core metal M that is press-fit into the steel tube 1A, thereby causing plastic flow of the processing wall 5 coming into contact with the tooth mold 24 from the inside to the outside of the steel tube 1A to form the racks 4 corresponding to the tooth mold 24; a core metal driving mechanism 40 for press-fitting the core metal M into the inside of the steel tube 1A held by the die 20; and an ultrasonic generation part 60 for providing ultrasonic vibration to the tooth mold 24.

Description

  The present invention relates to a hollow rack bar manufacturing apparatus and a hollow rack bar manufacturing method for manufacturing a hollow rack bar used in a power staying device for automobiles, and more particularly to an apparatus capable of improving productivity.

  As a manufacturing method of a hollow rack bar used for a power steering device of an automobile, there are many conventional methods by cutting from a round bar. However, in order to cope with a complicated shape and weight reduction, what is manufactured from a pipe material by transfer forging is known (for example, refer to Patent Document 1). Specifically, first, the pipe material is pressed with a cold forging die to form a flat upper surface as the first step of the tooth forming process, and then subjected to a bonde treatment, and in the next step, the pipe material is formed into a cavity. A mandrel is press-fitted. The metal core has a taper-shaped protrusion, and the protrusion engages with the flat part of the pipe material on the inner peripheral side, so that the meat of the flat part flows plastically toward the teeth of the mold. By doing so, a linear tooth row having a shape corresponding to the tooth row of the mold is applied to the outer peripheral flat portion of the pipe material by the transfer method, and a hollow rack bar can be obtained. In order to improve the moldability of the teeth, a processing oil may be applied between the mold and the pipe material.

  On the other hand, irregular vibrations such as chatter vibrations occur during machining due to friction with the pipe material during press-fitting of the core metal, and this vibration has an adverse effect on the processed product (pipe material), leading to a decrease in quality. There was a problem. For this reason, there is known a technique for preventing the occurrence of chatter vibration by connecting an ultrasonic generator to the base of the cored bar and applying necessary fine vibration to the cored bar (see, for example, Patent Document 2). ).

Japanese Examined Patent Publication No. 3-5892 JP 2000-94082 A

  The above-described method for manufacturing a hollow rack bar has the following problems. That is, if an attempt is made to secure a sufficient tooth width and height as a tooth portion (rack) formed on the hollow rack bar, it is difficult to mold. For example, the number of cored bars is increased and the production efficiency is lowered. In addition, the life of the mold is shortened and the manufacturing cost is increased. Further, the fiber flow of the tooth part is disturbed, and the strength and durability are lowered.

  Therefore, the present invention provides a hollow rack bar manufacturing apparatus and a hollow rack bar manufacturing method for manufacturing a hollow rack bar without reducing productivity while ensuring a sufficient tooth width and tooth height as a tooth portion. It is an object.

  In order to solve the above problems and achieve the object, the hollow rack bar manufacturing apparatus and the hollow rack bar manufacturing method of the present invention are configured as follows.

  A mold having a tooth mold, having both ends opened and a metal hollow material having a processing wall portion in which a rack is formed by the tooth mold; and the tooth by being press-fitted into the hollow material A metal core that plastically flows the processed wall portion in contact with the mold from the inside to the outside of the hollow material to form a rack according to the tooth mold, and the inside of the hollow material held by the metal mold. A press-fitting mechanism for press-fitting into the tooth mold, and an ultrasonic vibration applying mechanism for applying ultrasonic vibration to the tooth mold.

  A mold having a tooth mold, having both ends opened and a metal hollow material having a processing wall portion in which a rack is formed by the tooth mold; and the tooth by being press-fitted into the hollow material A metal core that plastically flows the processed wall portion in contact with the mold from the inside to the outside of the hollow material to form a rack according to the tooth mold, and the inside of the hollow material held by the metal mold. A press-fitting mechanism for press-fitting into the hollow material, and an ultrasonic vibration applying mechanism for applying ultrasonic vibration to the hollow material.

  A hollow material having a processing wall portion in which both ends are opened and a rack is formed by the tooth mold is held in a mold having a tooth mold, and is pressed into the hollow material to be inserted into the tooth mold. The core wall for forming the rack corresponding to the tooth mold is press-fitted by plastic flow of the processed wall portion in contact from the inside to the outside of the hollow material, and ultrasonic vibration is applied to the tooth mold.

  A hollow material having a processing wall portion in which both ends are opened and a rack is formed by the tooth mold is held in a mold having a tooth mold, and is pressed into the hollow material to be inserted into the tooth mold. A core metal for forming a rack corresponding to the tooth shape is press-fitted by plastically flowing the processed wall portion in contact from the inside to the outside of the hollow material, and ultrasonic vibration is applied to the hollow material.

  According to the present invention, it is possible to manufacture a hollow rack bar without reducing productivity while ensuring a sufficient tooth width and tooth height as a tooth portion.

The longitudinal cross-sectional view which shows the hollow rack bar manufacturing apparatus based on 1st Embodiment of this invention. The longitudinal cross-sectional view which shows the manufacturing process by the hollow rack bar manufacturing apparatus. The longitudinal cross-sectional view which shows the manufacturing process by the hollow rack bar manufacturing apparatus. The longitudinal cross-sectional view which shows the manufacturing process by the hollow rack bar manufacturing apparatus. The longitudinal cross-sectional view which shows the manufacturing process by the hollow rack bar manufacturing apparatus. The longitudinal cross-sectional view which shows the manufacturing process by the hollow rack bar manufacturing apparatus. The longitudinal cross-sectional view which shows the manufacturing process by the hollow rack bar manufacturing apparatus. The longitudinal cross-sectional view which shows the manufacturing process by the hollow rack bar manufacturing apparatus. The longitudinal cross-sectional view which shows the hollow rack bar manufacturing apparatus which concerns on 2nd Embodiment of this invention. The longitudinal cross-sectional view which shows the hollow rack bar manufacturing apparatus which concerns on 3rd Embodiment of this invention.

  FIG. 1 is a longitudinal sectional view showing a hollow rack bar manufacturing apparatus 10 according to a first embodiment of the present invention. The hollow rack bar manufacturing apparatus 10 manufactures the hollow rack bar 1 from a steel pipe (hollow material) 1A. 1 A of steel pipes have the one end opening 2 located in the left end in FIG. 1, and the other end opening 3 located in the right end in FIG. In the steel pipe 1A, a processing wall portion 5 is formed in advance at a central portion. A rack 4 is formed on the outer surface of the processing wall portion 5. The processed wall portion 5 is provided by crushing a part of the tube wall of the steel pipe 1A by pressing in the inner direction of the steel pipe 1A so as to be a flat surface.

  The hollow rack bar manufacturing apparatus 10 includes ultrasonic waves that apply ultrasonic vibrations to the metal mold 20, the metal core holder 30, the metal core drive mechanism (press-fit mechanism) 40, the metal core guide 50, and the tooth mold 24 described later. And a generator (ultrasonic vibration applying mechanism) 60.

  The mold 20 includes an upper mold 21 and a lower mold 22, and includes a mold clamping mechanism 23. The lower mold 22 is provided with a set groove 22a for placing the steel pipe 1A on the upper surface. The upper mold 21 is clamped and opened from above with respect to the lower mold 22 by the mold clamping mechanism 23.

  The upper die 21 is provided with a set groove 21a for sandwiching the steel pipe 1A on the lower surface. Moreover, the recessed part 21b of the set groove | channel 21a is provided, and the tooth type | mold 24 is mounted | worn so that removal is possible. A downward tooth portion 24 a having irregularities is formed at the lower end portion of the tooth mold 24. Further, the upper mold 21 is formed with a hole 21c into which a horn 63 described later is inserted from the side surface side.

  In a state where the mold is clamped, the set grooves 21a and 22a are joined together to sandwich the steel pipe 1A from above and below, and the tooth part 24a of the tooth mold 24 protrudes and abuts against the processing wall part 5 of the steel pipe 1A.

  The metal core holder 30 is provided with a plurality of holding holes 31, which pass through the metal core holder 30 in the direction in which the set grooves 21a and 22a extend, and the metal core M is individually provided therein. Contained. Each cored bar M supported by the cored bar holder 30 is positioned on a side where a first cored bar push rod 41 described later is inserted into and removed from the mold 20.

  The core metal holder 30 moves in the vertical direction in FIG. Each time this movement is performed, one of the plurality of holding holes 31 is sequentially selected and opposed to one end of the hole formed by the set grooves 21a and 22a. Therefore, the core metal M supported by the core metal holder 30 can be sequentially taken in and out of the steel pipe 1A.

  Each core bar M is made of metal. The core metal M is subjected to treatment for making its hardness and wear resistance higher than that of the steel pipe 1A. The length of the core metal M is set to be shorter than half of the length of the tooth portion 24a of the tooth mold 24. Further, the heights of the core bars M are all different. The core metal M is inserted into and removed from the core metal holder 30 during processing in order from the relatively low core metal M.

  The cored bar driving mechanism 40 includes a first cored bar pressing bar 41 and a first pressing bar driving unit 42, and a second cored bar pressing bar 43 and a second pressing bar driving unit 44. The first cored bar push bar 41 abuts on the left end of the cored bar M in FIG. 1 and has a function of being press-fitted into the steel pipe 1A by the first pusher bar drive unit 42. The second cored bar push bar 43 abuts on the right end of the cored bar M in FIG. 1 and has a function of being press-fitted into the steel pipe 1A by the second pusher bar drive unit 44.

  The ultrasonic generator 60 includes a cylindrical casing 61, a vibrator 62 accommodated in the casing 61, and a horn 63 attached to the end of the vibrator 62. The front end side of the horn 63 is inserted from the hole 21 c of the upper mold 21, and the front end is in contact with the tooth mold 24. Thereby, the ultrasonic wave generation unit 60 imparts vibration having a frequency of 20 KHz to 60 KHz and an amplitude of 1 to 10 μm to the tooth mold 24.

  A procedure for manufacturing the hollow rack bar 1 from the steel pipe 1A using the hollow rack bar manufacturing apparatus 10 described above will be described.

  As shown in FIG. 2A, the mold 20 is opened. As shown in FIG. 2B, the steel pipe 1A is set with its processing wall 5 facing upward in a state where the mold 20 is opened. One end opening 2 of the set steel pipe 1A is disposed in the mold 20, and the other end side of the steel pipe 1A protrudes from the mold 20 to the right in FIG. Further, as shown in FIG. 2C, the parts 5 a and 5 b on both sides of the processing wall portion 5 are clamped between the upper die 21 and the lower die 22 from the vertical direction by clamping, and are attached to the outer surface of the processing wall portion 5. The tooth mold 24 is brought into contact.

  Next, vibration is applied to the tooth mold 24 by the ultrasonic generator 60. This vibration continues until the next press-fitting of the core metal M is completed.

  Next, as shown in FIG. 2D, the cored bar holder 30 is operated to hold one of the plurality of cored bars M accommodated in the state facing the cored bar guide 50. At the same time, the tip of the first metal core push bar 41 is brought into contact with one end of the metal core M facing the metal core guide 50.

  Next, the second push rod drive unit 44 is operated to insert the second cored bar push rod 43 into the steel pipe 1A through the other end opening 3 of the steel pipe 1A. Along with this, the tip of the second cored bar 43 passes through the one end opening 2 of the steel pipe 1 </ b> A and the cored bar guide 50 and comes into contact with the other end of the cored bar M in the cored bar holder 30. Therefore, the cored bar M is sandwiched between the first cored bar pressing bar 41 and the second cored bar pressing bar 43 which are in contact with both ends from both ends in the axial direction.

  After that, as shown in FIG. 2E, the first driving unit 42 and the second driving unit 44 are operated, and the cored bar M is made up of the first cored bar pressing bar 41 and the second cored bar pressing bar 43. While being held, it is pressed by the first cored bar 41 and press-fitted into the steel pipe 1A. At this time, since the ultrasonic vibration is applied to the core metal M, no squeak is generated due to friction with the steel pipe 1A, thereby preventing chatter vibration and smooth press-fitting. Further, it is reciprocated between the first position P1 and the second position P2 shown in FIG.

  When the core metal M is reciprocated from the first position P1 to the second position P2 toward the mold 20, the core metal M causes the meat of the processing wall portion 5 of the steel pipe 1A to move from the inside of the steel pipe 1A. It is made to plastically flow so as to be pushed toward the outer tooth mold 24.

  Next, as shown in FIG. 2F, the first cored bar 41 is pulled back. At this time, the second cored bar push rod 43 is moved toward the cored bar holder 30. Thus, the core metal M is pressed by the second core metal push bar 43 while being held between the first core metal push bar 41 and the second core metal push bar 43 in contact with both ends of the core metal M. Then, it is pushed back into the core bar holder 30 through the core bar guide 50.

  Thereafter, as shown in FIG. 2G, the core metal holder 30 is moved so that the core metal M having the next largest projection amount is opposed to the opening of the steel pipe 1A through the core metal guide 50. Then, after the core metal M to be used next is sandwiched, the core metal M is similarly sandwiched between the first core metal push bar 41 and the second core metal push bar 43. Then, it is pressed by the first cored bar 41 and press-fitted into the steel pipe 1A and reciprocated once. By sequentially repeating these procedures, a hollow rack bar having a rack corresponding to the tooth mold 24 of the mold 20 on the steel pipe 1A is manufactured.

  Finally, after returning the last used metal core M to the metal core holder 30, the second metal core push rod 43 is extracted from the steel pipe 1A, and then the mold 20 is opened.

  As described above, since slight vibration is applied, even when a sufficient tooth width and tooth height are secured as a tooth portion, an excessive load is not generated on the steel pipe 1A due to press-fitting. It becomes possible to manufacture the hollow rack bar 1 without lowering. Further, the fiber flow of the rack 4 of the hollow rack bar 1 is not disturbed, and the strength and durability are improved.

  FIG. 2 shows a hollow rack bar manufacturing apparatus 10A according to the second embodiment of the present invention. 2 that are the same as those in FIG. 1 are assigned the same reference numerals, and detailed descriptions thereof are omitted.

  In the hollow rack bar manufacturing apparatus 10A, the position where the ultrasonic generator 60 is provided is different from that of the hollow rack bar manufacturing apparatus 10. That is, a hole 21 d that penetrates the set groove 21 a and the upper surface of the upper mold 21 is provided, and the horn 63 of the ultrasonic wave generation unit 60 is in contact with the upper surface of the tooth mold 24. As a result, the ultrasonic generator 60 applies fine vibrations to the tooth mold 24.

  Also in the hollow rack bar manufacturing apparatus 10A configured as described above, the hollow rack bar 1 can be manufactured without reducing the productivity as in the hollow rack bar manufacturing apparatus 10.

  FIG. 3 is a view showing a hollow rack bar manufacturing apparatus 10B according to the third embodiment of the present invention. 2 that are the same as those in FIG. 1 are assigned the same reference numerals, and detailed descriptions thereof are omitted.

  In the hollow rack bar manufacturing apparatus 10 </ b> B, the position where the ultrasonic generator 60 is provided is different from the hollow rack bar manufacturing apparatus 10. That is, a hole 22b that penetrates the set groove 22a and the lower surface of the lower mold 22 is provided, and the horn 63 of the ultrasonic generator 60 is in contact with the lower surface of the steel pipe 1A. Thereby, fine vibration is given to steel pipe 1A by ultrasonic generating part 60.

  Also in the hollow rack bar manufacturing apparatus 10 </ b> B configured as described above, the hollow rack bar 1 can be manufactured without reducing the productivity as in the hollow rack bar manufacturing apparatus 10.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Hollow rack bar, 1A ... Steel pipe (hollow material), 2 ... One end opening, 3 ... Other end opening, 4 ... Rack, 5 ... Processing wall part, 10 ... Hollow rack bar manufacturing apparatus, 20 ... Mold, 21 ... Upper die, 21a ... set groove, 21c ... hole, 22 ... lower die, 22a ... set groove, 23 ... mold clamping mechanism, 24 ... tooth mold, 30 ... core metal holder, 31 ... holding hole, 40 ... core metal drive Mechanism: 50 ... Metal core guide, 60 ... Ultrasonic generator, 63 ... Horn, M ... Metal core.

Claims (6)

A mold that holds a metal hollow material having a tooth mold, having both ends opened and a processing wall portion in which a rack is formed by the tooth mold;
A cored bar that plastically flows from the inside to the outside of the hollow material to form a rack according to the tooth type by press-fitting into the hollow material to contact the tooth type;
A press-fitting mechanism for press-fitting the cored bar into the hollow material held in the mold;
An apparatus for manufacturing a hollow rack bar, comprising: an ultrasonic vibration applying mechanism for applying ultrasonic vibration to the tooth mold. A mold that holds a metal hollow material having a tooth mold, having both ends opened and a processing wall portion in which a rack is formed by the tooth mold;
A cored bar that plastically flows from the inside to the outside of the hollow material to form a rack according to the tooth type by press-fitting into the hollow material to contact the tooth type;
A press-fitting mechanism for press-fitting the cored bar into the hollow material held in the mold;
An apparatus for manufacturing a hollow rack bar, comprising: an ultrasonic vibration applying mechanism that applies ultrasonic vibration to the hollow material. The core metal reciprocating mechanism is disposed on one side of the mold, supports the core metal, and allows the core metal to be inserted into one end opening of a hollow material held by the mold. A metal core holder for moving gold,
A first cored bar that is inserted into and removed from the hollow material through one end opening of the cored bar holder and the hollow material, and press-fits the cored bar into the hollow material by the insertion;
The metal core is inserted into and removed from the hollow material through the other end opening from the side opposite to the first metal core push rod, and the metal core is clamped with the first metal core push rod from the metal core holder. The hollow rack bar manufacturing apparatus according to claim 1, further comprising a second cored bar push bar that is pressed into the hollow material and pushed back toward the cored bar holder. Holding a hollow material having a processing wall part in which both ends are opened and a rack is formed by the tooth mold in a mold having a tooth mold,
Press-fitting a cored bar that plastically flows from the inside to the outside of the hollow material to form a rack according to the tooth type by being press-fitted into the hollow material,
A method for producing a hollow rack bar, wherein ultrasonic vibration is applied to the tooth mold. Holding a hollow material having a processing wall part in which both ends are opened and a rack is formed by the tooth mold in a mold having a tooth mold,
Press-fitting a cored bar that plastically flows from the inside to the outside of the hollow material to form a rack according to the tooth type by being press-fitted into the hollow material,
A method for producing a hollow rack bar, wherein ultrasonic vibration is applied to the hollow material.   The press-fit includes a first cored bar that is inserted into and removed from the hollow material through one end opening of a hollow material, and a second cored bar that is inserted into and removed from the material through the other end opening of the hollow material. And holding the cored bar disposed only on the side where the first cored bar is inserted into and removed from the mold, and preventing the cored bar from rotating at least with the first cored bar. The core metal is introduced into the hollow material from the one end opening by the double core metal push rods while maintaining the rotation prevention state, and then the hollow metal core is prevented from rotating by the first core metal push rod. The hollow according to claim 4 or 5, wherein after pressing into the material, the core metal is pushed back by the second core metal push rod while being sandwiched between the first core metal push rod. Rack bar manufacturing method.

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