JP5239050B2 - Brazed joint sintered parts - Google Patents

Description

  The present invention relates to a sintered part made by brazing and joining a first molded body having a boss portion and a second molded body having a bridge portion, and in particular, the first molded body and the second molded body have a quality problem. The present invention relates to a brazed joint sintered part that can be brazed and joined without inviting.

  Among the sintered parts manufactured by the powder metallurgy method, for example, there is one disclosed in Patent Document 1 below. The sintered part disclosed in Patent Document 1 is provided with a concave portion that causes a joint surface with a second molded body to be depressed on the end surface of the first molded body, and a bridge portion provided on the second molded body at the bottom of the concave portion. It is brazed with the tip of the butt.

  The first and second compacts are green compacts obtained by pressing and compacting metal powder, and the brazing of both is performed as follows. That is, the first molded body is overlaid on the second molded body with the bridge portion facing upward, and further, the entire chip is set in the brazing material set hole provided in the first molded body, and the whole is sintered. Introduce into the furnace. Then, heating is performed at a predetermined temperature for a predetermined time to sinter the first molded body and the second molded body, and the heat generated at that time is used to melt the brazing material in the brazing material set hole, and each part of the joint surface is caused by capillary action. The first molded body and the second molded body are joined to each other.

In addition, although the recessed part of the end surface of a 1st molded object is provided for the purpose of positioning with a 2nd molded object, and prevention of the overflow of a brazing material (making the dredging material pool for that arise around a joining surface). The positioning of the first molded body and the second molded body is also performed by a method of providing a positioning convex portion on the joint surface of the second molded body as disclosed in Patent Document 2 below.
JP 2003-251457 A JP 56-89374 A

  In the sintered component disclosed in Patent Document 1, the first molded body has a boss portion, and a concave portion that causes the joint surface to sink into the first molded body having the boss portion is brought close to the boss portion installation region. If provided, this will cause cracks at the base of the boss.

  The reason for this will be described with reference to FIGS. 7 and 8 is a first molded body having a boss portion 4 concentric with the center hole 2 on one surface side of the base portion 3. A concave portion 16 is provided on the surface of the base portion 3 opposite to the boss portion installation side in the vicinity of the boss portion installation region 5, and the bottom of the concave portion 16 is used as a joint surface with the second molded body. . A hole penetrating the bottom of each recess 16 is used as the saddle material setting hole 8. In the first molded body 1 shown in FIGS. 7 and 8, since the amount of powder in the portion a (see FIG. 8) where the recess 16 is formed increases, the density of the portion a is the density of the portion b arranged between the recesses. Higher than. The density of the part c disposed between the center hole 2 and the recess 16 is influenced by the molding of the part a, so that there is almost no difference from the density of the part a, and the part d (boss) shown in FIG. The density of the portion 4) is set so that the lower two punches (not shown) for molding the end face of the boss portion 4 are restrained (if the deflection amount is large, the lower two punches at the time of depressurization after powder forming) The elastic restoring amount increases and the first molded body breaks), and is made smaller than the density of the part b.

  If there is the concave portion 16, such a density difference is generated, and among these, the density difference between the portions b and c causes distortion at the base of the boss portion 4, which easily causes a crack at the base of the boss portion 4. .

  In addition, since the structure disclosed in Patent Document 2 has a limited size of the positioning recess, even if the first molded body is provided with a recess, the above-described problem is unlikely to occur. In the structure provided, the problem of brazing failure is likely to occur due to the problem of reduction in the area of the joint surface and inhibition of penetration of the brazing material due to the convex portions and concave portions. Further, if the positioning convexity or recess does not surround the joining surface, the brazing material overflows around the joining surface, resulting in poor appearance of the sintered part.

  The present invention provides a defect in manufacturing sintered parts by allowing the first molded body and the second molded body having a boss portion to be brazed and joined without causing quality problems such as cracks, poor bonding, and poor appearance. The problem is to reduce the incidence.

In order to solve the above problems, in the present invention, the first molded body having a boss portion and the second molded body having a bridge portion are brought into contact with the boss portion installation region of the first molded body. The following elements were added to the sintered parts produced by the splicing and joining. That is, the first molded body is formed with a convex portion surrounding the joint surface in an endless state, the area of the region surrounded by the convex portion is made larger than the area of the joint surface, and further, the convex portion A plurality of portions for positioning the second molded body in contact with a part of the outer periphery of the bridge portion are provided, a circumferential positioning function is provided in at least one of them, and a radial positioning function is provided in at least one other location. In addition, the joint surface of the first molded body was flush with the end surface of the boss portion installation region.

  Since the sintered part of this invention formed the convex part which surrounds a joining surface in the 1st molded object, the effect of positioning of a 2nd molded object and the overflow prevention of a saddle material, without sinking the joining surface of a 1st molded object Can be obtained. For example, a space is created between the convex portion and the bridge portion that enters the convex portion by making the area of the region surrounded by the convex portion larger than the area of the joint surface surrounded by the convex portion, The surplus dredged material is taken in there and the overflow of dredged material is prevented.

  In addition, since the joining surface of the first molded body is provided in the same plane as the end surface of the boss portion installation region, there is no significant density difference at the base of the boss portion of the first molded body. The occurrence of cracks due to the distortion of the root is prevented, and the defect occurrence rate during manufacturing is reduced.

Furthermore, since the site | part which positions the 2nd molded object in contact with a part of outer periphery of the said bridge | bridging part was provided in the said convex part, positioning of a 2nd molded object can be performed by a convex part . Position-decided Me sites are granted positioning function in the circumferential direction of the positioning function and the radial direction in a plurality of positions, in order that, to achieve both the formation of the space for taking the excess brazing filler metal, a stable positioning of the second shaped body be able to.

  Hereinafter, embodiments of the method of the present invention will be described. FIG. 1 shows an example of a sintered part 20 of the present invention. The illustrated sintered component 20 is a planetary carrier for planetary gears, which sinters the first molded body 1 and the second molded body 10 made by pressure-molding metal powder, and the second molded body. 10 is manufactured by brazing the first molded body 1 to the tip of the bridge portion 11 provided in 10.

  The first molded body 1 includes a plate-like base portion 3 having a center hole 2, a boss portion 4 concentric with the center hole 2 provided on one surface of the base portion 3, and a boss portion installation region as shown in FIG. 5, a plurality of joint surfaces 6 formed around the center hole 2, a convex portion 7 provided around each joint surface 6, and a saddle material setting hole 8 that opens to each joint surface 6. . Each joint surface 6 is in the same plane as the end surface 9 of the boss portion installation region 5.

  Moreover, the 2nd molded object 10 has the bridge | bridging part 11 of the same number as the joint surface 6 in the one surface side of the base 13 (this becomes an end plate of the other side of a planetary carrier) which has the center hole 12. FIG. Each bridge part 11 has the same cross-sectional shape as the joining surface 6 of the 1st molded object 1, The front-end | tip of this bridge part 11 abuts on the joining surface 6, and is brazed and joined.

  The convex part 7 continues in an endless state, and surrounds each joint surface 6 by making one round. As shown in FIG. 2 and FIG. 3, the convex portion 7 is partly in contact with the contour edge of the joint surface 6 and the other part is separated from the contour edge of the joint surface 6, and as shown in FIG. Two forms can be considered in which the entire region contacts the contour edge of the joint surface 6. In the structure of FIG. 3, a part of the outer periphery of the bridge portion 11 that abuts on the joint surface 6 is in contact with the convex portion 7, and the gap g formed between the bridge portion 11 and the convex portion 7 is pooled and joined. Excess dredged material overflowing from the interface is taken in there.

  In addition, the dimension L of the gap g in the structure of FIG. 3 and the height H of the convex portion 7 (see FIG. 4) are the surplus saddle material taken into the gap g when the joint surface 6 is in the downward direction, The surface tension is set so that it can be held in the gap g. In the embodiment, the dimension L and the height H are both about 1 mm. The thickness t of the convex part 7 was good at 1.5 mm or less.

In the structure of FIG. 3, and the positioning portions ₁₅ -1 _{to 15 -3} on the convex portion 7 is provided, the positioning portions ₁₅ -1 _{to 15 -3,} in contact with the outer periphery of the bridge portion 11 as shown in FIG. 5 To do. Among these, the positioning part _15-1 has a radial positioning function, the positioning parts _15-2 and _15-3 have a circumferential positioning function, and there are a plurality of joints of the same structure. The positioning of the first molded body and the second molded body is stably performed.

In the structure of FIG. 3, the circumferential direction of the positioning the positioning portion ₁₅ -2 2 points, ₁₅ but made by _-3, the protrusion 7 and the bridge portion 11 in the example portion of the positioning portion _{15 -1} in FIG If the concave and convex fitting portion that enters in the radial direction is provided, positioning in the circumferential direction can also be performed at one positioning portion.

  As shown in FIG. 1, the first molded body 1 and the second molded body 10 configured as described above have the second molded body 10 facing down and the first molded body 1 stacked on the bridge portion 11 facing upward. Match. And the brazing material chip | tip 14 is inserted in the brazing material set hole 8 provided in the 1st molded object 1, The whole is introduce | transduced in a sintering furnace (not shown) in this state, and the 1st molded object 1 and 2nd shaping | molding The body 10 is sintered. At the same time, the brazing material chip 14 is melted and permeated into the bonding interface by capillary action, and the tip of the bridge portion 11 and the bonding surface 6 of the first molded body are brazed together.

  At this time, the excess brazing material overflowing from the bonding interface is taken into the gap g in FIG. 3 and held in the gap g by the surface tension. Therefore, dripping of the brazing material along the surface of the bridge portion 11 does not occur. Therefore, the appearance of parts does not deteriorate. Further, since the convex portion is outside the joining surface and does not hinder the penetration of the brazing material, the brazing material spreads over the entire area of the joining interface, so that no brazing failure occurs. Furthermore, since the 1st molded object 1 is a thing without a recessed part, the crack of the boss | hub part root of the 1st molded object resulting from the distortion which arises because of a density difference is also prevented, and a defective rate reduces. It is expected to improve production yield and reduce costs.

  Note that the structure shown in FIG. 3 forms a space for dredging, so that it is not necessary to strictly adjust the size of the wood chip necessary for the structure shown in FIG. The structure of 3 is more advantageous than the structure of FIG.

Sectional drawing which shows an example of the sintered part of this invention in the state which accumulated the 1st molded object and the 2nd molded object FIG. 1 is an end view of the first molded body constituting the sintered part of FIG. FIG. 2 is an enlarged end view showing a part of FIG. Sectional drawing which expands and shows a part of 1st molded object The expanded sectional view of the part along the AA line of FIG. Enlarged end view showing a modification of the convex portion provided in the first molded body Sectional drawing of the 1st molded object of the conventional structure which formed the recessed part and depressed the joint surface FIG. 7 is an end view of the first molded body on the joint surface installation side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st molded object 2 Center hole 3 Base part 4 Boss part 5 Boss part installation area | region 6 Joint surface 7 Convex part 8 Saddle material setting hole 9 End surface 10 of a boss part installation area | region 2nd molded object 11 Bridge part 12 Center hole 13 Base 14 Brazing material chip 15 _-1 to 15 _-3 Positioning part 16 Concave part 20 Sintered part g Gap L Gap dimension H Convex part height t Convex part thickness ad

Claims (2)

The first molded body (1) having the boss portion (4) and the second molded body (10) having the bridge portion (11), and the boss portion installation region (5) of the bridge portion (11) being the first molded body. a sintered parts were brazed bonded butt, the bonding surface (6) forms a convex portion (7) surrounding at endless state to the first molding body (1), in the convex portion (7) The area of the enclosed region is made larger than the area of the joint surface (6), and the second molded body (10) is in contact with the convex portion (7) and part of the outer periphery of the bridge portion (11). A plurality of positioning portions (15) are provided, and at least one of them has a circumferential positioning function and at least one other has a radial positioning function, and the first molding is performed. bonding surface of the body (6) the end surface of the boss installation region on the same plane as (9) Braze bonding sintered components, characterized in that the. The positioning part (15) is provided at a position corresponding to both the both side surfaces and the outer diameter surface of the bridge part (11), and between each positioning part, between the convex part (7) and the bridge part (11). The brazed joint sintered part according to claim 1, wherein a gap (g) is formed as a pool of wrinkles .

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