JPH0637644B2 - Manufacturing method of planetary carrier - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a planetary carrier used in a transmission.

[Conventional technology]

The planetary carrier is used in an auxiliary transmission that is used in a vehicle automatic transmission together with a fluid coupling or a torque converter. For example, as shown in FIG. 4, several planetary gears 31 are supported and a ring gear 32 is used. And sun gear
It rotates on the same axis as 33.

Conventionally, this planetary carrier is manufactured by cast iron or steel plate by full-circumference machining, but the number of machining steps is large,
Since the equipment will increase and the cost will increase, the inner spline 3a at the center as shown in FIG.
A plate-shaped body 30c having four planetary gear mounting holes 30b at the four corners, and a plate-shaped body 30f having a shaft hole 30d at the center and four planetary gear mounting holes 30e at the four corners, with a space for mounting the planetary gears. As a result, a planetary carrier having a shape in which side plates 30g are connected at the center of each side is manufactured. In the figure, 30h represents a through hole into which brazing is inserted during brazing. Since this sintered planetary carrier has a structure in which a space is formed by the plate-shaped body 30c, the plate-shaped body 30f and the side plate 30g, it cannot be integrally molded from the sintering powder and is divided into two parts. It is manufactured by separately molding, sintering, and joining the two. That is, as shown in FIG. 6, two members, that is, a member made of a plate-shaped body having a shaft hole 30d and a side plate and a member made of a plate-shaped body 30c having an inner spline 30a, are manufactured by molding sintering powder. Manufactured by stacking the two sintered bodies obtained, then placing the brazing material in the through hole 30h provided at the position corresponding to the end face 30i of the side plate 30g, heating and brazing the two. Has been done.

As a related technology, there is Japanese Patent Publication No. 58-34524.

[Problems to be solved by the invention]

As described above, when the planetary carrier is divided into two parts, separately molded and sintered, and two sintered bodies are stacked and joined by brazing, it is difficult to position the two, and After that, there is a problem that the two are displaced from each other when they are moved into the furnace. Therefore, it is conceivable to provide a fitting portion for positioning on both of them, but in the past, when joining, the brazing filler metal often penetrated into the sintered body, and the brazing filler metal soaked in the sintered body. Since the sintered body expands when it is incorporated, if the expansion is restrained by the fitting portion, distortion occurs inside the sintered body, and there is a problem that the strength of the sintered body is significantly reduced. Also, when there is a difference in expansion and contraction between the two, distortion similarly occurs.

The present invention is intended to solve the above problems, and an object thereof is to provide a method of manufacturing a planetary carrier having high dimensional accuracy and strength.

[Means for solving problems]

The method of manufacturing a planetary carrier of the present invention comprises a compacted powder for sintering, has a shaft hole in the center, has side plates upright at the edges, and has a central axis of the planetary carrier at the end face of the side plate. The first member made of a plate-like body having a concave line provided in the radial direction with respect to the center is also pressure-molded with sintering powder, and has an inner spline on one surface and the above on the other surface. A second member, which is a plate-like member that fits in the groove and has a convex portion that extends in the radial direction around the central axis of the planetary carrier and that has a through hole at a position corresponding to the end face of the side plate, It is characterized in that the concave strip and the convex portion are overlapped with each other without leaving a gap so that the brazing material is put into the through hole of the second member, and the sintering and the brazing are simultaneously performed.

The concave stripes provided on the first member and the convex portions provided on the second member are for positioning both members. By providing them in the radial direction around the central axis of the planetary carrier, there is a difference in expansion and contraction between the two members. Even if it occurs, the direction of expansion and contraction coincides with the radial direction, so that the concave line and the convex part are displaced from each other while being fitted, and the stress is relieved. A total of two sets in the two radial directions centering on the center axis of the above acts only to alleviate strain in a certain direction, and is not sufficient to alleviate strain in all directions. Although the strain can be relaxed, the stress relaxation does not improve even if the number of fittings exceeds eight, despite the increase in the number of fitting parts. High precision is required, so it is better to provide 3 to 8 pairs. May each pair provided in each joint.

Further, the width of the top of the convex portion of the second member in the circumferential direction with respect to the central axis of the planetary carrier is, as shown in FIG. 7, necessary to secure the strength required for the carrier (tensile strength 440 Pa or more). In order to obtain a density of 6.6 g / cm ² or more for the powder compact for sintering, it is preferably 10 mm or less. this is,
When the width of the top of the convex portion exceeds 10 mm, the flow distance of the powder during molding becomes long, the powder does not move sufficiently to the convex portion, and the convex portion, that is, the thick portion and other portions are the same. This is because the weight of the powder is molded, so that the density of the convex portions becomes small. When Fe-Cu-C based powder is used as the sintering powder, shrinkage due to sintering and expansion due to Cu cause
The density of the molded body and the density of the sintered body are almost equal.

Examples of the brazing filler metal that can be used in the present invention include Ni
-Cu-Mn-Fe-Si-B-based brazing material can be used, and when the boron-based flux is added to the brazing material, it suppresses oxidation of the brazing material and improves wettability to the joint surface. The brazing material spreads evenly over the entire joint surface, as a result of which no joint failure occurs, the joint strength is improved, and the existing oxides are melted in the flux and solidified after brazing and vitreous in the through hole. It is preferable to add a lid because it functions to prevent the remaining brazing filler metal from separating in the through hole.

As described above, as the brazing material, when the Ni-Cu-Mn-Fe-Si-B type brazing material and the mixed compact of the boron compound flux are used, the Ni-Cu-Mn-Fe-Si-B type brazing material is joined. Per area
If it is less than 0.1 g / cm ² , the brazing filler metal does not spread over the entire joint surface and some parts are left unjoined, while if it exceeds 0.6 g / cm ² , it overflows from the joint surface and remains in the through holes. Ni-Cu-Mn-Fe-Si-B based brazing filler metal is added in an amount of 0.1 to 0.6 in order to increase
It is preferably used so as to be g / cm ² .

[Work]

The planetary carrier manufacturing method of the present invention comprises a first member, which is formed by pressure-molding sintering powder, has a shaft hole in the center, and has a side plate that is upright on the edge, and an inner spline. The second member, which is a plate-shaped member, is positioned by fitting the concave line provided on the first member and the convex part provided on the second member, and the two members are overlapped for sintering and brazing. Therefore, it is possible to obtain a highly accurate sintered body without displacement of both members. At this time, the two members are overlapped with each other without leaving a gap, the brazing filler metal is put into the through hole of the second member, and the sintering and the brazing are simultaneously performed, so that the brazing filler metal is melted and soaked between the through holes. Incorporation, both members are joined together without a gap and become a sintered body.

The concave stripes of the first member are provided in the radial direction around the central axis of the planetary carrier, and the convex portions of the second member are provided in a shape extending in the radial direction around the central axis of the planetary carrier. Therefore, even if there is a difference in expansion and contraction of both members during sintering and brazing,
Since the shrinking direction coincides with the radial direction, the central axes of both members do not shift, the recessed lines and the projecting parts move with each other while they are fitted, the stress is relieved, and no strain is generated inside the sintered body.

The reason why the convex portion for positioning is provided on the second member is that when the convex portion is provided on the first member, the joint surface on which the convex portion is provided is the lower surface at the time of molding. When it is pulled out, the convex portion interferes and cannot be slid out from the mold, resulting in poor workability. On the other hand, if the second member is provided with the concave portion, the density of the second member becomes 6.4 g / cm ² , and the density required to secure the strength required for the planetary carrier cannot be obtained. This is a part where the thickness of the molded body is larger than the recess,
That is, there are many areas with low density. Therefore,
This is because if the molding pressure is further increased to increase the density, the allowable load of the mold will be exceeded and the life of the mold will be shortened.

〔Example〕

The present invention will be described by way of examples with reference to the drawings. In addition,
Hereinafter,% means% by weight.

Example 1 A powder for sintering was prepared by adding 0.8% of zinc stearate to a mixed powder of 2% of electrolytic copper powder of -250 mesh, 0.8% of graphite powder of -350 mesh, and the balance of atomized iron powder of -100 mesh. Compression molded to 6.8 g / cm ² , Fig. 2
As shown in (a) and (b), it has an upright tubular shaft hole 15 at the center of the lower surface, and side plates 12 are provided on each of the four sides of the upper surface.
Which has a concave section having a square cross section and is provided in the center of the end face 13 of each side plate 12 in the radial direction about the central axis of the planetary carrier
A first member 10 composed of a substantially rectangular plate-like body 11 having 14;
As shown in FIGS. 1 (a) and (b), there is an inner spline 22 consisting of four parts on the outer circumference of the upper surface, and the lower surface is fitted with the recessed line 14, and radiated about the central axis of the planetary carrier. A ring-shaped plate-shaped body 21 having a rectangular rail-shaped convex portion 24 having a width of 10 mm provided in the direction and having a through-hole 23 at a position corresponding to the end surface 13 of the side plate 12 of the first member 10. Two members 20 were obtained.

As brazing material, Ni30%, Mn15%, Fe15%, Si2%, B1
% And the balance Cu-42 Mesh atomized alloy powder
97%, boron compound flux (AWS No. 5) 3
%, The wax was weighed so as to have a bonding area of 0.3 g / cm ^2, and molded at 5 t / cm ² to obtain a molded body.

Then, the concave stripes 14 of the first member 10 and the convex portions 24 of the second member 20 are fitted to each other to be positioned, and the second member 20 is opened above the first member 10 as shown in FIG. Directly, put the brazing compact in the through hole 23 of the second member 20, preheat and dewax in nitrogen gas at 700 ° C for 30 minutes, and then at 1130 ° C.
Sinter brazing was performed for 30 minutes. The brazing filler metal evenly flowed over the entire joint surface of the first member 10 and the second member 20, and the brazing filler metal did not overflow from the joint portion. In addition, there is no misalignment due to the concave and convex portions provided in the radial direction, the stress is relieved, there is no deformation due to distortion during brazing, and both members are well joined, and the planetary carrier has high dimensional accuracy and strength. was gotten.

Example 2 A mixed powder obtained by adding 0.8% of zinc stearate to a sintering powder consisting of 2% of electrolytic copper powder of -250 mesh, 0.8% of graphite powder of -350 mesh, and the balance of atomized iron powder of -100 mesh, has a density of 6.8. Compression molding was performed so as to obtain g / cm ² to obtain a first member and a second member having the same shape as in Example 1. However, the width of the top of the convex portion of the second member in the circumferential direction with respect to the central axis of the planetary carrier was 5 mm, and the size of the concave line of the first member was a size that fits the convex portion.

Thereafter, both members were stacked and sintered and brazed under the same conditions as in Example 1 in the same manner as in Example 1.

The brazing filler metal flows evenly on the joint surface, and there is no protrusion from the joint. The excess brazing material remained in the through hole in the form of glass. Furthermore, neither the positional displacement of the two members, nor the distortion or the deformation occurred, and the planetary carrier of high precision and high strength was obtained.

〔The invention's effect〕

As described above, the planetary carrier manufacturing method according to the present invention is provided with two members, which are fitted to each other and radially slidably provided with a concave groove and a convex portion, and both members are provided with the concave groove and the convex portion. Positioning, brazing filler metal in the through hole, sintering and brazing at the same time, both members are joined well, no positional displacement or distortion occurs, and a planetary carrier with high dimensional accuracy and strength can be obtained. You can Further, since both members are easily positioned, it has many advantages such as excellent productivity.

[Brief description of drawings]

1 (a) is a plan view of a second member of a planetary carrier molded body according to an embodiment of the present invention, FIG. 1 (b) is a sectional view of the member of FIG. 1 (a), and FIG. a) is a plan view of a first member of a molded body for a planetary carrier according to an embodiment of the present invention, FIG. 2 (b) is a sectional view of the member of FIG. 2 (a), and FIG. FIG. 4 is a cross-sectional view of a molded body for a planetary carrier of an example, FIG. 4 is a configuration diagram of a planetary gear train according to a conventional technique, FIG. 5 is a perspective view of a conventional sintered planetary carrier, and FIG. FIG. 7 is a perspective view of the bound planetary carrier, and FIG. 7 is a graph showing the relationship between the width of the top of the convex portion of the second member and the density of the molded body. In the figure, 10 ... First member, 11 ... Plate, 12 ... Side plate, 14 ... Recess, 15 ... Shaft hole, 20 ... Second member, 21 ... Plate, 22 ... … Inner splines, 23 …… through holes, 24 …… projections.

Claims (4)

[Claims] 1. A press-molded powder for sintering, which has a shaft hole in the center, has a side plate standing upright at the edge, and has an end face of the side plate in a radial direction about the central axis of the planetary carrier. The first member consisting of a plate-shaped body having a concave line formed in the same manner is also formed by press-molding sintering powder, and has an inner spline on one surface and is fitted to the concave line on the other surface. The second member formed of a plate-like body having a convex portion extending in the radial direction around the center axis of the planetary carrier and having a through hole at a position corresponding to the end face of the side plate is provided with the concave line and the convex line. A method for manufacturing a planetary carrier, characterized in that the two parts are stacked without a gap so that the parts fit together, a brazing material is put into the through hole of the second member, and sintering and brazing are performed simultaneously. 2. The method according to claim 1, wherein the width of the top of the convex portion of the second member in the circumferential direction with respect to the central axis of the planetary carrier is 10 mm or less. 3. The method according to claim 1, wherein a molded body of a Ni—Cu—Mn—Fe—Si—B type brazing material and a boron compound flux is used as the brazing material. 4. The method according to claim 3, wherein the Ni-Cu-Mn-Fe-Si-B-based brazing material is used in an amount of 0.1 to 0.6 g per 1 cm ² of the bonding area.