JPH1137253A - Sintered internal gear and method of manufacturing sintered internal gear - Google Patents

Abstract

[PROBLEMS] To provide a sintered internal gear having good gear accuracy while reducing the number of steps to reduce manufacturing costs. A helical gear (13) has a substantially cylindrical shape, and an outer cylindrical body (15) having a gear portion (14) formed on an inner peripheral surface thereof. The flange portion 16 is formed integrally in advance. A joint portion 17 between the outer cylindrical body 15 and the outer peripheral end portion 16b of the flange portion 16 penetrates the inside and outside of the outer peripheral wall 15d, and the oil insertion hole 1 through which lubricating oil is inserted into the brake clutch device 9.
8, 18 are formed in advance during compression molding.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a sintered internal gear and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a conventional internal gear of this type, for example, a gear used in a planetary gear device 2 of an automatic transmission 1 described in Japanese Patent Application Laid-Open No. 5-58178 shown in FIG. Are known.

In such a vehicle, an automatic transmission 1 for a vehicle is used.
The planetary gear device 2 disposed therein has a helical gear 3 as an internal gear in which a sun gear portion 4a formed around a shaft 4 to be inserted and a plurality of planetary gears 5 are disposed. I have. This helical gear 3
Has an outer cylindrical body 6 having a substantially cylindrical shape and forming a gear portion 6a on an inner peripheral surface, and one end 6 of the outer cylindrical body 6 in a thrust direction.
The outer peripheral edge 7a is connected to the outer peripheral edge 7b by beam welding, and is mainly constituted by a substantially disk-shaped hub 7 having an insertion opening 7b through which the shaft 4 is inserted at a substantially central portion. .

[0004] The outer cylindrical body 6 has oil insertion holes 6c, 6c, which penetrate the inside and outside of the outer peripheral wall 6c, and through which lubricating oil is inserted into the brake clutch device 9 located further outside, and are formed by drilling. .

In the conventional helical gear 3 configured as described above, as shown in FIG. 12, lubricating oil supplied from an oil insertion passage 4b formed substantially at the center of the shaft 4 is formed on the outer wall of the shaft 4. The oil flows out from the oil holes 4c, 4d and the like.

The lubricating oil is supplied to the thrust bearings 10 and 10 which support the hub 7 in the thrust direction so as to be rotatable, the sun gear 4a, the plurality of planetary gears 5 and the gears of the helical gear 3. The oil insertion hole 6c is formed by centrifugal force while lubricating the tooth surface of the portion 6a.
, And reaches the brake clutch device 9 to lubricate the clutch plates 9a, 9b,.

[0007]

However, in such a conventional helical gear 3, the outer peripheral edge 7a of the hub 7 is connected to one end 6b of the outer cylinder 6 in the thrust direction by beam welding. Therefore, there is a possibility that the beam welded portion may rise and interfere with the peripheral member 11 and the like.

Further, due to the poor beam welding, burrs are generated on one end edge 6b of the outer cylindrical body. Further, since the oil insertion holes 6c, 6c are formed by drilling, burrs also occur at the peripheral portions of the oil insertion holes 6c, 6c.

As described above, in order to remove burrs generated at a plurality of locations, a separate finishing step is required, and there is a problem that the number of steps is increased.

There is also a problem that the outer cylindrical body 6 is thermally deformed by the heat at the time of beam welding, and the gear accuracy of the gear portion 6a formed on the inner peripheral surface is deteriorated.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sintered internal gear having a reduced gear number, a reduced manufacturing cost, and a high gear accuracy.

[0012]

According to a first aspect of the present invention, an internal gear portion is formed inside a substantially cylindrical outer cylinder, and a thrust direction of the outer cylinder is formed. A sintered internal gear integrally formed with a substantially disk-shaped flange portion at one end edge thereof, wherein the sintered internal gear has an oil lubrication hole formed near a joint between the outer cylindrical body and the flange portion; It features a null gear.

According to the first aspect of the present invention, an oil lubrication hole is formed near a joint between the outer cylindrical body and the flange portion of the sintered internal gear. An oil lubrication hole through which the lubricating oil flows out is formed from the inside to the outside through the outer cylindrical portion by the mold moving along the thrust direction from the part side.

For this reason, the sintered internal gear can be easily demolded, and the sintered internal gear obtained by compressing and sintering the sintered metal material can be provided with a conventional drill or the like. Oil lubrication holes are formed without the need for drilling holes and beam welding.

Therefore, it is possible to reduce the number of steps required for deburring and the like, thereby reducing the manufacturing cost.

Further, since the outer cylindrical body and the flange portion can be integrally molded in advance during compression molding, beam welding or the like is not required as in the conventional case. Therefore, there is no possibility that the outer cylindrical body is thermally deformed by beam welding or the like, and the gear accuracy is improved.

According to the second aspect of the present invention, the internal gear portion is formed inside the substantially cylindrical outer cylindrical body, and a substantially disc-shaped one end edge of the outer cylindrical body in the thrust direction is provided. A method for manufacturing a sintered internal gear in which a flange portion is integrally formed, wherein when a sintered metal raw material is compression-molded, an oil lubrication hole is formed near a joint between the outer cylindrical body and the flange portion. It features a sintered internal gear to be formed.

According to the second aspect of the present invention, since the oil lubrication hole is formed near the joint between the outer cylindrical body and the flange portion of the sintered internal gear, the flange is formed. With the mold moving along the thrust direction from the part side, it is possible to form an oil lubrication hole through which the lubricating oil flows out from the inside to the outside via the outer cylindrical portion.

[0019] For this reason, die cutting can be easily performed, and the sintered internal gear obtained by compressing and sintering the sintered metal raw material can be drilled by a drill or the like which has been conventionally performed.
Oil lubrication holes can be formed without the need for beam welding or the like.

Accordingly, it is possible to reduce the number of processes that have conventionally been required for deburring and the like, thereby reducing the manufacturing cost.

Further, since the outer cylindrical body and the flange portion can be integrally formed in advance during compression molding, beam welding or the like is not required as in the conventional case. Therefore, there is no possibility that the outer cylindrical body is thermally deformed, and the gear accuracy is improved.

[0022] According to the third aspect,
A sintered internal gear in which an internal gear portion is formed inside a substantially cylindrical outer cylindrical body, and a substantially disk-shaped flange portion is integrally formed at one end of the outer cylindrical body in a thrust direction. At a joint portion between one end of the outer cylindrical body in the thrust direction and the outer peripheral end of the flange portion, an oil lubrication hole forming projection projecting from a die inserted and removed in the thrust direction is clamped. It is characterized by a method of manufacturing a sintered internal gear to be positioned.

According to the third aspect of the present invention, the lubricating hole forming projection protruding from the mold inserted and withdrawn in the thrust direction includes one end edge of the outer cylinder in the thrust direction, It is positioned in a mold-clamped state at a joint portion with the outer peripheral end of the flange portion.

For this reason, since the oil lubrication holes are formed after the die is removed, there is no need to form the oil lubrication holes with a drill or the like after sintering.

Accordingly, the step of opening a hole by a drill and the step of deburring the periphery of the opening can be omitted, and the manufacturing cost can be reduced.

According to a fourth aspect of the present invention, the protrusion for forming the oil lubrication hole is formed on the upper punch member which is clamped from the outer side of the flange portion, and is formed along the thrust direction. By providing relative movement in the direction opposite to the punch member, a lower punch member forming the internal gear portion is provided, and the tip of the oil lubrication hole forming protrusion is provided on the lower punch member in a mold clamped state. A method for manufacturing a sintered internal gear according to claim 3 is provided.

The upper and lower punch members may be configured such that a tip of the oil lubrication hole forming projection formed on the upper punch member is connected to the lower punch member. Stop moving in the relative direction at the position where it abuts.

For this reason, the lubrication hole forming projection can be stopped at the root position of the internal gear portion in the thrust direction with respect to the flange portion. There is no risk of the oil lubrication hole forming projections entering.

Therefore, the internal gear portion can form the tooth portion over the entire circumference up to the vicinity of the base portion.

Therefore, a sintered internal gear having good space efficiency in the thrust direction can be manufactured.

According to a fifth aspect of the present invention, the projection for forming the oil lubrication hole partially overlaps with the flange forming portion of the lower punch member in the thrust direction, and the flange forming portion is formed. A method for manufacturing a sintered internal gear according to any one of claims 3 and 4, characterized in that the internal gear is slidably contacted with the outer side surface of the portion at a position where a tooth tip circle is formed in the radial direction internal gear.

According to the fifth aspect of the present invention, the flange forming portion of the lower punch member forming the internal gear is located above the root of the internal gear in the mold clamped state. Can be located. Therefore, compression molding can be performed between the upper and lower punch members so that the flange portion is provided in a position where the oil lubrication hole is formed, with the size of the flange portion suppressed in the outer diameter direction.

Further, since the oil lubrication hole forming projections are nested in sliding contact with the outer surface of the flange portion at the radial internal gear tooth tip circle forming position. The lower punch member can be brought close to the predetermined compression completed position in the thrust direction without interference.

[0034]

Embodiment 1 Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. The same or equivalent parts as those in the conventional example are denoted by the same reference numerals and described.

FIGS. 1 to 11 show a sintered internal gear according to Embodiment 1 of the present invention and a method of manufacturing the same.

First, the structure of the sintered internal gear according to the first embodiment will be described. As shown in FIG. 4, the sintered internal gear is inserted into a planetary gear device 12 disposed in the automatic transmission 1 of the vehicle. A sun gear portion 4a formed around the shaft 4 and a plurality of planetary gears 5 meshing with the sun gear portion 4a and rotating around the shaft 4 together with the carrier plates 5a and 5b are provided as sintered internal gears. A helical gear 13 is provided.

The helical gear 13 has a substantially cylindrical shape, and has an outer cylindrical body 15 having a gear portion 14 formed on an inner peripheral surface thereof, and a first end 15a of the outer cylindrical body 15 in the thrust direction.
A substantially disk-shaped flange portion 16 is integrally formed in advance.

Among them, on the outer peripheral surface of the outer cylindrical body 15, an uneven portion 15b for holding the clutch plates 9a of the brake clutch device 9 located further outside is formed over the entire circumference.

The outer cylinder 15 and the flange 16
At the joint portion 17 with the outer peripheral end portion 16b, oil insertion holes 18, 18 which penetrate the inside and outside of the outer peripheral wall 15d and penetrate the lubricating oil into the brake clutch device 9 are formed in advance during compression molding.

An insertion opening 16a for inserting the shaft 4 is formed substantially at the center of the flange portion 16. Bearing holding recesses 16c, 16c for holding the thrust bearings 10, 10 for supporting the flange portion 16 in the thrust direction are formed on both inner and outer side surfaces of the flange portion 16.

Next, the helical gear 1 of the first embodiment
3 will be described with reference to FIGS.

As shown in FIG. 6, the molding die used in the compression molding according to the first embodiment is provided at a position corresponding to the position where the shaft 4 is provided, and the insertion opening 16a of the flange portion 16 is provided. Substantially cylindrical core rod 10 that forms
1 is provided.

A die 102 in which an annular molding space for accommodating the sintered metal material is formed substantially at the center of the core rod 101 is arranged in advance.

The core rod 101 and the die 102
Between the first to third lower punch members 1 as annular molds
03 to 105 are provided. Among them, the second lower punch member 104 is provided with a spiral gear generating portion 104a that forms the gear portion 14 as an internal gear portion.

The first to third lower punch members 1
03 to 105, the flange portions 1 to 3 face the first to lower punch members 103 to 105, respectively.
6. An upper punch member 106 is provided as a mold for performing mold clamping by sliding down along the thrust direction from above, which is the outside direction.

The lower side 106 of the upper punch member 106
5A, one end 15a in the thrust direction of the outer cylindrical body 15 and the outer peripheral end 16b of the flange portion, as shown in FIG.
Is inserted in the thrust direction at the joint portion 17 with the mold, and is inserted and withdrawn in the thrust direction.
8, the lubrication hole forming projections 107, 107
They are integrally protruded at symmetrical positions with respect to the central axis.

On the lower surface 106a of the upper punch member 106, an annular concave portion 108 forming the bearing holding portion 16c is formed.

The protrusion 107 for forming the oil lubrication hole is formed as shown in FIG.
As shown in (2), during compression molding, by being relatively moved in a direction opposite to the second lower punch member 104 in the thrust direction, the second lower punch member 104 is provided in a mold-clamped state. Upper end part 104 of gear generation part 104a
It is configured such that the tip 107a is brought into contact with b.

The lubricating hole forming projections 107
Partially overlaps the flange forming portion 104c of the second lower punch member 104 in the thrust direction, and forms a radial internal gear tooth tip circle with respect to the outer surface 104d of the flange forming portion 104c. At a position (a position indicated by a one-dot chain line in FIG. 7), it is configured to slidably contact with each other.

In FIG. 6, for the sake of explanation, the raw material filling state is shown on the left side of the center line h, and the compressed state is shown on the right side of the center line h.

Next, the operation of the first embodiment will be described.

First, a sintered metal raw material (iron powder or other metal powder and a lubricant for improving fluidity during molding) are mixed and mixed at a predetermined ratio by a mixer. A certain weight is filled into the molding space of the mold.

That is, as shown on the left side of the center line h in FIG. 6, with the upper punch member 106 retracted upward, the sintered metal raw material is filled until it is flush with the upper surface of the die 102. .

As shown on the right side of the center line h in FIG. 6, the upper punch member 106 of the molding die and each of the first
To the lower punch members 103 to 105 and the core rod 10.
3 to 7 from the vertical direction by sliding along 1
Compression molding is performed by applying a pressure of tonf / cm 2.

At this time, at the same time as the upper punch member 106 is slid down from above along the thrust direction, the first to third lower punch members 103 to 105 are raised to perform mold clamping.

At the time of mold clamping, as shown in FIG. 7, the upper and second lower punch members 106 and 104 are formed with the lubricating hole forming projections 107 formed on the upper punch member 106.
The movement in the relative direction is stopped at a position where the tip 107a of the second lower punch member 104 contacts the upper end portion 104b of the gear generation portion 104a of the second lower punch member 104.

For this reason, the lubricating hole forming projection 107 can be stopped at the root position of the gear portion 14 in the thrust direction with respect to the flange portion 16 (the position indicated by the one-dot chain line b in FIG. 7). Up to a part of the gear portion 14,
There is no danger of the oil lubrication hole forming projection 107 entering.

Therefore, in the helical gear 13 of the first embodiment, the gear portion 14 can be formed over the entire circumference up to the position a near the base.

As a comparative example, a case will be described with reference to FIGS. 8 and 9 where the position where the tip 107a contacts the upper end portion 104b of the gear generation portion 104a is shifted in the thrust direction.

In FIG. 8, the upper end portion 10 of the gear generation section 104a is shown.
This shows a case where the position b1 at which the tip 4b contacts the tip 107a is closer to the flange 16 than the position b.

In this case, when the upper end portion 104b of the gear generating portion 104a formed on the second lower punch member 104 is inserted and removed while rotating, the hatched portion 11a is attached to the tip 107a.
0, as shown by the two-dot chain line in FIG.
07a cannot be lowered and the mold cannot be clamped.

FIG. 9 shows a case where the position b2 at which the upper end portion 104b of the gear generation portion 104a contacts the tip 107a is more distant from the flange portion 16 than the position b.

In this case, the upper end portion 104b of the gear generation portion 104a formed on the second lower punch member 104 is separated from the front end portion 107a, and a gap 111 (hatched portion in the figure) is generated. The gear 14 cannot be formed.

Therefore, in the case shown in FIGS. 8 and 9, it is impossible to form the helical gear 13 and to form the gear portion 14 all the way around the base portion.

In the first embodiment, as shown in FIG. 7, the flange forming portion 104c of the second lower punch member 104 forming the gear portion 14 in the mold-clamped state is connected to the base of the gear portion 14. It can be located higher than the part. For this reason, even at the position where the oil lubrication hole 18 is formed, compression molding can be performed between the upper edge 104 e of the flange portion forming portion 104 c and the upper punch member 106, and the size of the outer peripheral edge of the flange portion 16 that is missing is reduced. It can be provided while being suppressed.

The oil lubrication hole forming projection 107
Are nested in sliding contact with the outer side surface 104d of the flange portion forming portion 104c at the radial internal gear tooth tip circle forming position a, so that both upper punch members 106 and second lower punch members 102 Can be brought close to a predetermined compression completed position in the thrust direction without interference.

Next, as another comparative example, FIG. 10 and FIG.
1, the oil-lubricating-hole-forming projection 107 is positioned on the outer side surface 104d of the flange-portion forming portion 104c.
The case of sliding contact at positions other than the radial internal gear tooth tip circle forming position a will be described.

FIG. 10 shows a case where the outer side surface 104d is formed at a position a1 shifted radially inward. In this case, a space 113 is formed below the outer peripheral end portion 16b of the flange portion 16, and there is no pressing against the gear generation portion 104a.
(Shaded area) will be missing.

FIG. 11 shows a case where the inner sliding contact surface of the oil lubrication hole forming projection 107 is shifted to the radially inner position a2.

In this case, the second lower punch member 104
Outside of the flange portion forming portion 104c formed at the front end 1
07a interferes with the hatched portion 114, and the mold cannot be clamped.

Therefore, in the case shown in FIGS. 10 and 11, a part of the flange portion 16 cannot be formed, or the helical gear 13 itself cannot be formed due to poor mold clamping.

Therefore, as shown in FIG. 7, the mold clamping position in the thrust direction is aligned at the base position b of the gear portion 14 and the radial sliding contact position is adjusted at the tooth tip position a of the gear portion 14. , The good mold clamping can be performed, and
The oil insertion holes 18, 18 can be formed so as to communicate the inside and outside in the radial direction of the outer cylindrical body 15.

Therefore, since the oil lubrication holes 18 are formed near the joint 17 between the outer cylindrical body 15 of the helical gear 13 and the flange portion 16, the oil lubrication holes 18 move in the thrust direction from the flange portion 16 side. Oil lubrication holes 18, 18 through which the lubricating oil flows out are formed from the inside to the outside through the outer cylindrical body 15 portion by a mold in which the substantially annular upper and lower punch members 103 to 106 and the like are combined.

For this reason, the helical gear 13 is removed from the mold.
Each upper and lower punch member 10 having a substantially annular shape along the thrust direction.
Only 3 to 106 and the like are moved in the vertical direction in FIG. 7, and the combination is easily performed in a complicated combination as compared with the case where insertion and removal must be performed in the radial direction.

The helical gear 13 obtained by compressing and sintering the sintered metal raw material does not require drilling or the like which has been conventionally performed, and does not require beam welding.
Oil lubrication holes 18 are formed.

Therefore, it is possible to reduce the number of steps that have conventionally been required for deburring and the like, thereby reducing the manufacturing cost.

Also, in advance, at the time of compression molding, the outer cylinder 1
Since the flange 5 and the flange 16 are integrally formed, beam welding or the like is not required as in the related art. Therefore, there is no possibility that the outer cylindrical body 15 is thermally deformed by beam welding or the like, and the gear accuracy of the gear portion 14 formed inside is improved.

Then, the lubricating hole forming projection 10 projecting from the upper punch member 106 inserted and withdrawn in the thrust direction.
7 is one end 15a of the outer cylindrical body 15 in the thrust direction.
Joint 1 between the flange 16 and the outer peripheral end 16b
At 7, it is located in a mold-clamped state.

For this reason, since the oil lubrication holes 18 are formed after the upper punch member 106 is extracted, there is no need to form the oil lubrication holes with a drill or the like after sintering.

Therefore, the step of opening a hole by a drill and the step of deburring the periphery of the opening can be omitted, and the manufacturing cost can be reduced.

Next, the compression-molded powder compact is heated in a sintering furnace at a high temperature below the melting point for a certain period of time, so that diffusion bonding of metal particles progresses and alloys are formed.

After this baking step, if the dimensional accuracy is insufficient, in order to further improve the quality and characteristics and obtain a finished product according to the purpose of use and use, the sintered body is removed. A so-called sizing process in which the material is pressed into a sizing die, recompressed, and the dimensions are corrected is performed in a post-processing process of the internal gear manufacturing process.

After sizing, inspection is performed to obtain a helical gear 13 as a finished product.

As described above, the oil lubrication holes 18 and 1 through which the lubricating oil flows out from the inside to the outside through the outer cylindrical body 15.
4, the lubricating oil supplied from the oil insertion passage 4b formed substantially at the center of the shaft 4 is supplied to the oil hole 4c formed in the outer wall of the shaft 4 as shown by an arrow in FIG. , 4d and the like, and thrust bearings 10 for supporting the hub 7 in the thrust direction so as to be rotatable, and the sun gear 4
a, a plurality of planetary gears 5,... and a gear portion 6a of the helical gear 3 while lubricating the tooth surfaces thereof, reach the brake clutch device 9 via the oil insertion holes 18, 18 by centrifugal force, and each clutch plate 9a , 9b ... are lubricated.

Although the first embodiment of the present invention has been described in detail with reference to the drawings, the specific structure is not limited to the first embodiment, and there are design changes and the like within a range not departing from the gist of the present invention. Even this is included in the present invention.

For example, in the first embodiment, the gear 1
Although a helical gear is used as 4, it is not particularly limited to this, and a gear shape of another shape such as a normal spur gear may be used.

In the first embodiment, the oil insertion hole 1
Although a pair of 8 and 18 are provided at symmetrical positions, the present invention is not particularly limited to this. For example, the outer cylindrical body of the sintered internal gear and the flange portion may be joined together by forming a single or a plurality of three or more places. If it is formed near the part,
The quantity, shape, size, and the like are not limited to the first embodiment.

[0088]

As described above, according to the first aspect of the present invention, the oil lubrication hole is provided near the joint between the outer cylindrical body and the flange of the sintered internal gear. Is formed, an oil lubrication hole through which the lubricating oil flows out is formed from the inside to the outside via the outer cylindrical portion by the mold moving along the thrust direction from the flange portion side.

Therefore, the die is easily removed from the sintered internal gear, and the sintered internal gear obtained by compressing and sintering the sintered metal material is subjected to a conventional drill or the like. Oil lubrication holes are formed without the need for drilling holes and beam welding.

Therefore, it is possible to reduce the number of steps that have conventionally been required for deburring and the like, thereby reducing the manufacturing cost.

Further, since the outer cylindrical body and the flange portion can be integrally formed at the time of compression molding in advance, beam welding or the like is not required as in the conventional case. Therefore, there is no possibility that the outer cylindrical body is thermally deformed by beam welding or the like, and the gear accuracy is improved.

According to the second aspect of the present invention, the oil lubrication hole is formed near the joint between the outer cylindrical body and the flange of the sintered internal gear.
An oil lubrication hole through which lubricating oil flows out can be formed from the inside to the outside via the outer cylindrical portion by the mold moving along the thrust direction from the flange portion side.

[0093] For this reason, the die can be easily removed, and the sintered internal gear obtained by compressing and sintering the sintered metal material can be drilled by a drill or the like which has been conventionally performed.
Oil lubrication holes can be formed without the need for beam welding or the like.

Therefore, it is possible to reduce the number of steps which have conventionally been required for deburring and the like, thereby reducing the manufacturing cost.

Further, since the outer cylindrical body and the flange portion can be integrally formed at the time of compression molding in advance, beam welding or the like is not required as in the conventional case. Therefore, there is no possibility that the outer cylindrical body is thermally deformed, and the gear accuracy is improved.

[0096] According to the third aspect,
An oil lubrication hole forming projection projecting from a mold inserted and withdrawn in the thrust direction has one end edge in the thrust direction of the outer cylindrical body,
It is positioned in a mold-clamped state at the joint with the outer peripheral end of the flange portion.

[0097] For this reason, since the oil lubrication holes are formed after the die is removed, there is no need to form the oil lubrication holes with a drill or the like after sintering.

Therefore, the step of opening a hole by a drill and the step of removing the burrs around the opening can be omitted, and the manufacturing cost can be reduced.

According to the fourth aspect of the present invention, in the upper and lower punch members, the tips of the oil lubrication hole forming projections formed on the upper punch member abut on the lower punch member. Stop moving in the relative direction at the position.

For this reason, the lubrication hole forming projection can be stopped at the position of the root portion of the internal gear portion in the thrust direction with respect to the flange portion. There is no risk of the oil lubrication hole forming projections entering.

Therefore, the internal gear portion can form the tooth portion over the entire circumference up to the vicinity of the base portion.

Therefore, a sintered internal gear having good space efficiency in the thrust direction can be manufactured.

According to the fifth aspect of the present invention, the flange forming portion of the lower punch member forming the internal gear is positioned above the base of the internal gear in the mold-clamped state. Can be done. Therefore, compression molding can be performed between the upper and lower punch members so that the flange portion is provided in a position where the oil lubrication hole is formed, with the size of the flange portion suppressed in the outer diameter direction.

Further, since the oil lubrication hole forming projections are nested in sliding contact with the outer side surface of the flange portion at the radial internal gear tooth tip circle forming position, This has a practically useful effect that the lower punch member can be brought close to the predetermined compression completion position in the thrust direction without interference.

[Brief description of the drawings]

FIG. 1 is a front view showing a configuration of a helical gear according to Embodiment 1 of the present invention.

FIG. 2 is a rear view showing the configuration of the helical gear according to the first embodiment.

FIG. 3 is a cross-sectional view illustrating a configuration of a main part of the helical gear according to the first embodiment, taken along a line AA in FIG. 1;

FIG. 4 is a cross-sectional view illustrating a state in which the helical gear according to the first embodiment is applied to a planetary gear device used in an automatic transmission.

FIG. 5 is a perspective view illustrating a configuration of an upper punch member, which is one of the molds for the helical gear according to the first embodiment.

FIG. 6 is a cross-sectional view illustrating a method of manufacturing the helical gear according to the first embodiment and illustrating a configuration of a molding die.

FIG. 7 is an enlarged sectional view illustrating a method of manufacturing the helical gear according to the first embodiment and illustrating a configuration of a main part of a molding die.

FIG. 8 is an enlarged cross-sectional view of a molding die showing a configuration of a comparative example for describing a method of manufacturing the helical gear according to the first embodiment.

FIG. 9 is an enlarged cross-sectional view of a molding die showing a configuration of another comparative example for explaining a method of manufacturing the helical gear according to the first embodiment.

FIG. 10 is an enlarged cross-sectional view of a molding die showing a configuration of another comparative example for describing a method of manufacturing the helical gear according to the first embodiment.

FIG. 11 is an enlarged cross-sectional view of a molding die showing a configuration of still another comparative example for describing a method of manufacturing the helical gear according to the first embodiment.

FIG. 12 is a cross-sectional view illustrating a conventional internal gear and illustrating a state where the internal gear is applied to a planetary gear device used in an automatic transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 13 Helical gear (sintered internal gear) 14 Gear part (internal gear part) 15 Outer cylinder 15a One end edge in the thrust direction 16 Flange part 16b Outer peripheral end part 17 Joint part 18, 18 Oil insertion hole Die 101 Core rod 102 Die 103 To 105 First to third lower punch members 106 Upper punch member 104a Gear generation portion 104b Upper end portion 104c Flange portion forming portion 104d Outer side surface 104e Upper end edge 107 Projection portion 107a for forming oil lubrication hole

Claims (5)

[Claims] An internal gear portion is formed inside a substantially cylindrical outer cylinder, and a substantially disc-shaped flange is integrally formed on one end of the outer cylinder in a thrust direction. A sintered internal gear, which is a null gear, wherein an oil lubrication hole is formed near a joint between the outer cylindrical body and the flange portion. 2. A sintered interface in which an internal gear portion is formed inside a substantially cylindrical outer cylinder, and a substantially disc-shaped flange is integrally formed on one end of the outer cylinder in a thrust direction. A method of manufacturing a null gear, comprising forming an oil lubrication hole near a joint between the outer cylindrical body and the flange when compressing a sintered metal material. Null gear. 3. A sintered interface in which an internal gear portion is formed inside a substantially cylindrical outer cylinder, and a substantially disc-shaped flange is integrally formed on one end of the outer cylinder in a thrust direction. A null gear, wherein a lubricating hole forming projection projecting from a mold inserted and withdrawn in the thrust direction is provided at a joining portion between one end edge in the thrust direction of the outer cylindrical body and the outer peripheral end of the flange portion. A method for manufacturing a sintered internal gear, comprising: 4. The oil-lubricating-hole-forming projection is formed on an upper punch member which is clamped from the outside of the flange portion, and is opposed to a direction facing the upper punch member along a thrust direction. A lower punch member forming the internal gear portion is provided by moving, and a tip end of the oil lubrication hole forming protrusion contacts the lower punch member in a mold-clamped state. Item 4. The method for producing a sintered internal gear according to Item 3. 5. The oil-lubricating-hole forming projection part partially overlaps in a thrust direction with a flange part forming part of the lower punch member, and a radial direction with respect to an outer surface of the flange part forming part. The method for manufacturing a sintered internal gear according to claim 3 or 4, wherein the internal gear has a nested sliding contact at a position where a tip circle of the internal gear is formed.