JP2013066921A - Die set for helical gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate initializing of a die set for forming a helical gear for subserviently rotating a lower punch at the time of guiding and rotating a die during formation in a guiding section having a guide groove of the same lead angle as a forming helical tooth.SOLUTION: The die set has a die 1, a lower punch 2 and an upper punch 3 on whose periphery helical teeth Gand Gbiting the forming helical tooth Gof the die are formed, a core rod 4 and a guiding section 5 provided with a guide groove 5a having the same lead angle as the forming helical tooth. The upper punch 3 is thrust into the die 1 so that raw material powder P in a cavity 19 is compacted. At this time, in the die set for forming the helical gear in which the lower punch 2 rotates subserviently with the die, a positionally fixed guide holder 9 is provided with a ball plunger 17. The ball of the ball plunger engages with a concavity for engaging provided on the periphery of the mounting location of the lower punch 2, in a position where the phase of the guiding section 5 and the phase of the lower punch 2 coincide so that the positioning of the guiding section 5 and the lower punch 2 is kept.

Description

  The present invention relates to a helical gear mold used for forming a powder compact in the production of a sintered helical gear.

  Sintered helical gears are produced by sintering the obtained powder compact after going through a raw powder compaction process. One of the molds used in the compacting process for helical gears is disclosed in FIG.

  The metal mold (powder molding apparatus) shown in FIG. 4 of the same document has an external tooth for forming a helical gear, and a molding screw is formed on the inner circumference as the lower punch and the die move relative to each other in the axial direction. The die having rotation is guided and guided by a guide portion in which a guide groove of the same lead as that of the forming helical member and a cam follower are combined.

  In addition, the upper punch that has entered the die is also guided by the guide portion and rotates to synchronize with the die. Furthermore, since the rotation of the die is transmitted to the lower punch due to the molding pressure, the lower punch is made independent of the guide portion where the position of the guide groove is fixed to protect the die by following the die. ing.

Japanese Patent Laid-Open No. 10-113793

  The metal mold shown in FIG. 4 of Patent Document 1 matches the phase of the lower punch and the guide portion, and in this state, the die is fitted to the outer periphery of the lower punch to set the metal mold in the initial state.

  However, in these dies, since the lower punch and the guide part can be freely rotated relative to each other, phase alignment (positioning) and maintenance of the positioning state are not easy, and time and labor are required for the initial setting of the dies. Was right.

  It is an object of the present invention to facilitate the initial setting of the above-mentioned mold for rotating the lower punch following the die while guiding and rotating the die at the guide portion during molding.

In order to solve the above problems, the present invention provides the following helical gear mold.
(I) a die provided with a forming hull on the inner periphery, a lower punch and an upper punch formed on the outer periphery with a hull meshing with the forming hull of the die, a core rod, and the forming hull A guide portion having a guide groove with the same lead as the base, and the die, the lower punch, and the upper punch are rotatably supported,
The upper punch meshes with the die with the die for molding, and is pushed into the die while rotating to compress the raw material powder in the cavity formed between the die, the lower punch, the core rod, and the upper punch. Sometimes, in the mold for forming helical gears, the lower punch rotates following the die.
A ball plunger is provided in a fixed guide holder at a position having the guide groove, and the ball of the ball plunger urged by an elastic body is positioned at a position where the phase of the guide portion and the lower punch coincides. A mold that engages with a recess for engagement provided on the outer periphery of the mounting portion.

  This mold is for forming a helical gear with external teeth.

  These molds can achieve the object of the invention if there is at least one pair of the above-mentioned ball plunger and engaging recess, but a plurality of such ball plungers and engaging recesses are provided at a constant pitch in the circumferential direction. preferable.

  In addition, the said ball plunger uses what can cancel | release the engagement of the ball | bowl with respect to the recessed part for engagement by the rotational force which acts on a lower punch at the time of powder molding.

  In the mold of this invention, the ball of the ball plunger provided on the guide portion installation member enters the engaging recess provided on the outer periphery of the lower punch mounting portion at a position where the phases of the guide portion and the lower punch coincide. Engage. Therefore, phase alignment (positioning) between the guide portion and the lower punch is simple.

  In addition, during the initial setting of the mold, a large relative rotational force does not act on the guide part and the lower punch, so that the positioning state of both by the ball plunger is stably maintained. It becomes easy to do without spending.

  When a rotational force is transmitted from the rotating die to the lower punch when the mold is used (powder molding), the engagement of the ball plunger with the engaging recess of the ball is naturally released by that force, and the lower punch is released. It becomes rotation free. Therefore, the function of protecting the lower punch by following the rotation of the die is ensured as in the conventional product.

Sectional drawing which shows the example which applied this invention to the metal mold | die for external-tooth helical gears Enlarged cross-sectional view of the main part of the mold of FIG. Sectional view along line III-III in FIG.

  Embodiments of a helical gear mold according to the present invention will be described below with reference to FIGS. 1 to 4 of the accompanying drawings.

  The helical gear mold (die set) in FIG. 1 forms a helical gear with external teeth and includes a die 1, a lower punch 2, an upper punch 3, and a core rod 4. Moreover, it has the guide part 5 which guides and rotates a die | dye. The die 1, the lower punch 2, the upper punch 3, and the core rod 4 create a cavity 19 between the four members.

  The die 1 is supported by a die plate 6. The die plate 6 is connected to the yoke plate 8 driven by the lower ram 21 of the press machine via the connecting rod 7. The lower punch 2 is attached to the base plate 10 using a punch holder that also serves as the guide holder 9, and the core rod 4 is fixed to the yoke plate 8.

  Further, the upper punch 3 is attached to the upper plate 11 driven by the upper ram 22 of the press machine. Reference numeral 12 denotes a guide plate disposed above the die plate 6. The guide plate 12 has a guide stopper 13 attached to the base plate 10 and is supported by the guide stopper 13.

  Further, the upper plate 11 is connected to the guide plate 12 via a cylinder 14 (which is an air cylinder in the figure) that is operated by fluid pressure. Reference numeral 15 denotes a guide portion that rotates the upper punch 3 when the upper punch 3 descends.

On the inner periphery of the die 1, a forming hoop G ₁ inclined with a predetermined lead angle is formed, and on the outer peripheries of the lower punch 2 and the upper punch 3, the forming hull G ₁ is fitted. Molds G ₂ and G ₃ are formed to mesh with each other.

  Further, the die 1 and the upper punch 3 are supported by a bearing 16 and are rotatable. The lower punch 2 is also supported by the guide holder 9 so that rotation at a fixed position is allowed. The lower punch 2 may be supported via a bearing in the same manner as the upper punch. However, the amount of rotation of the lower punch during molding is not so large, so that there is no particular problem even with support without a bearing. .

Guide portion 5 is formed by combining cam follower 5b to be guided by the guide groove 5a and the guide groove in G ₁ and the same lead angle if you are molding. The guide groove 5 a is formed in the guide holder 9 whose position is fixed, and the cam follower 5 b is attached to the die 1.

Guide portion 15 is also formed by combining the cam follower 15b is guided by the guide groove 15a and its guide grooves in G ₁ and the same lead angle if you are molding. The guide groove 15a is formed on the outer periphery on the base end side of the upper punch 3, and the cam follower 15b is attached to the guide plate 12 whose position is fixed.

  The guide holder 9 is provided with a ball plunger 17 that characterizes the present invention. The ball plunger 17 is as shown in FIG. 2, that is, a ball 17b is provided in the hollow screw 17a so as to be able to protrude and retract, and the ball 17b is urged by an elastic body 17c (coil spring) to There are commercially available products that protrude from the tip.

  The ball plunger 17 is screwed into a screw hole 9 a provided in the guide holder 9, and the ball 17 b protrudes from the inner peripheral surface of the guide holder 9 by a predetermined amount.

  Further, on the outer periphery of the attachment portion provided on the base end side of the lower punch 2, an engagement recess 18 is provided in which the ball 17 b of the ball plunger 17 is fitted and engaged. The concavity 18 for the engagement is preferably conical because of excellent centripetality.

Its engaging recesses 18 are ball 17b of the ball plunger 17 is provided at a position fitted when match (G ₂ phase if you are molding) phase of the lower punch 2 of the guide portion 5. For this purpose, the lower punch 2 is inserted into the guide holder 9 in advance, and the ball plunger 17 can maintain the state in which the ball 17b is fitted in the engaging recess 18 (positioning state of the lower punch 2 and the guide holder 9).

  If the die 1 is fitted to the outer periphery of the lower punch 2 in this state, the positioning state does not change. Therefore, the initial setting of the mold can be easily performed without taking time and effort.

  Further, when the upper punch 3 is driven and pushed into the die 1, and the raw powder P put into the cavity 19 is molded by the pushing and a rotational force is applied to the lower punch 2, the ball 17 b compresses the elastic body. Then, it escapes and disengages from the engaging recess 18, thereby preventing the lower punch 2 from rotating freely and applying an excessive twisting force to the lower punch.

  As shown in FIG. 3, a plurality of ball plungers 17 and engaging recesses 18 are provided at a constant pitch in the circumferential direction, and any one of the ball plungers 17 and any one of the engaging recesses 18 are engaged. When the phase of the guide portion 5 and the lower punch 2 is matched, the phase alignment operation is facilitated, and the holding stability of the phase aligned (positioned) state is also increased.

DESCRIPTION OF SYMBOLS 1 Die 2 Lower punch 3 Upper punch 4 Core rod 5, 15 Guide part 5a, 15a Guide groove 5b, 15b Cam follower 6 Die plate 7 Connecting rod 8 Yoke plate 9 Guide holder 10 Base plate 11 Upper plate 12 Guide plate 13 Guide stopper 14 Cylinder 16 Bearing 17 Ball plunger 17a Hollow screw 17b Ball 17c Elastic body 18 Recess 19 for engagement 19 Cavity 21 Lower ram 22 Upper ram G ₁ , G ₂ , G ₃ Shaping P Material powder

Claims (2)

A die (1) provided with a forming hull (G ₁ ) on the inner periphery, and a lower punch (2) formed with hulls (G ₂ , G ₃ ) engaged with the forming hull for the die on the outer periphery (2) ) And an upper punch (3), a core rod (4), and a guide portion (5) provided with a guide groove (5a) of the same lead as the molding helical,
The die (1), the lower punch (2), and the upper punch (3) are supported rotatably,
The upper punch (3) meshes with the die (1) with a forming mold, and is pushed into the die (1) while rotating to be pushed into the die (1), the lower punch (2), and the core rod (4). The raw powder (P) in the cavity (19) formed between the upper punch (3) is compressed, and at this time, the lower punch (2) rotates following the die (1). In the mold for gear molding,
A ball holder (17) is provided in a fixed guide holder (9) at a position having the guide groove (5a), and the ball (17b) of the ball plunger biased by an elastic body (17c) (5) and the lower punch (2) are engaged with an engaging recess (18) provided on the outer periphery of the mounting portion of the lower punch (2) at a position where the phases of the lower punch (2) coincide with each other. Gear mold.   The helical gear mold according to claim 1, wherein a plurality of the ball plungers (17) and the engaging recesses (18) are provided at a constant pitch in the circumferential direction.

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