JP2012135997A - Mold for injection molding of carrier for planetary gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold for injection molding of a carrier for a planetary gear, which is capable of suppressing the falling of the supporting shaft of the carrier caused by the injection molding so as to eliminate the need for an another part (annular plate) for correcting the falling of the supporting shaft of the carrier after the injection molding.SOLUTION: Molten plastic injected from a pinpoint gate fills the second cavity part and thereafter fills the first cavity part. In this case, the molten plastic flowing out from the opening of the second cavity part into the first cavity radially and uniformly flows out to the periphery of the second cavity part. As the result, in the carrier for the planetary gear injection molded in the mold 2 for injection molding, the falling of the supporting shaft is suppressed. Further, the molten plastic filling the second cavity flows into the third cavity.

Description

The present invention relates to an injection mold for a carrier for a planetary gear device used in a power transmission system of an automobile, an industrial machine or the like.

Generally, the planetary gear device changes rotation transmitted from a power source such as a motor into a rotation convenient for driving other driven devices.

8 and 9 show an example of such a planetary gear device 100. FIG. As shown in FIGS. 8 and 9, the planetary gear device 100 has an input shaft 1 in the gear case 101.
The input side sun gear 102 that rotates integrally with 02a, a plurality of planetary gears 103 that mesh with the input side sun gear 102, and a carrier 104 that supports the planetary gear 103 so that it can revolve around the input side sun gear 102. And is housed. The carrier 104 has a support shaft 106 that rotatably supports the planetary gear 103 on one side surface 105 of the planetary gear 10.
Same number as 3. The carrier 104 is the other side 107 and the carrier 1.
An output-side sun gear 110 that meshes with another planetary gear 108 is provided at the center of rotation of 04. The planetary gear 103 that is rotatably supported by the support shaft 106 of the carrier 104 meshes with the input-side sun gear 102 and is formed on the inner peripheral surface 11 of the gear case 101.
1 is engaged. The other planetary gear 108 that meshes with the output-side sun gear 110 of the carrier 104 is rotatably supported by a support shaft 114 of another carrier 113 that rotates integrally with the output shaft 112, and is supported on the inner peripheral surface of the gear case 101. It also meshes with the formed internal gear 115 (see Patent Document 1).

In recent years, such a planetary gear device 100 has a gear case 101, an input side sun gear 102, a planetary gear 1, in order to improve the quietness of operation noise, reduce the overall weight, and reduce the product price.
In some cases, the component parts such as 03 and the carrier 104 are formed by plastic (injection molding) (see Patent Document 2).

FIG. 10 is a diagram schematically showing the structure of the injection mold 120 of the carrier 104. As shown in FIG. 10, the injection mold 120 includes a cavity 121 for forming the carrier 104 and a pinpoint gate 122 for injecting molten plastic into the cavity 121 ( (See FIG. 8). The cavity 121 includes a first cavity portion 123 for forming the disk-shaped carrier main body 116, a plurality of (the same number as the support shafts 106) second cavity portions 124 for forming the plurality of support shafts 106, and the output side sun. Gear 11
And a third cavity portion 125 for forming 0 (see FIG. 8). A pinpoint gate 122 opens at the center of the first cavity portion 123.

When the carrier 104 is injection molded with such an injection molding die 120, FIG.
As shown in (b), the planetary gear 103 is caused by a difference in shrinkage when the plastic is cooled.
The support shaft 106 that rotatably supports the shaft tends to fall toward the inner side (the rotation center 126 side of the carrier 104). In FIG. 11B, the regular (designed) support shaft 106 is indicated by a two-dot chain line, and the support shaft 106 that has fallen is indicated by a solid line.

When the inclination (θ, ε) toward the inside of the support shaft 106 of the carrier 104 becomes large, the distance between the rotation centers of the planetary gear 103 and the input-side sun gear 102 meshing with the planetary gear 103 becomes too short.
The teeth of the planetary gear 103 and the teeth of the input-side sun gear 102 are squeezed together (interference between the tooth tip and the bottom of the tooth) to generate noise, and smooth rotation transmission becomes impossible (FIG. 8, FIG. 11). Further, due to the galling of the teeth of the planetary gear 103 and the teeth of the input side sun gear 102, uneven wear occurs between the teeth of the planetary gear 103 and the teeth of the input side sun gear 102, and the durability of the planetary gear device 100 is improved. It will cause a decline. In FIG. 11B, θ is a tilt angle of the support shaft 106 inward in the radial direction, and the center line 109 of the support shaft 106 with respect to the virtual line 118 parallel to the rotation center line 117 of the carrier 104. And θ = 0 ° when the rotation center line 117 of the carrier 104 and the center line 109 of the support shaft 106 are parallel to each other. In FIG. 11B, ε represents the amount of displacement of the tip end of the support shaft 106 inward in the radial direction.

To solve such a problem, as shown in FIGS.
The support shaft 106 of the carrier 104 is inserted into the support hole 131 of the annular plate 130 manufactured separately from
The support shaft 10 of the carrier 104 is supported by the support hole 131 of the annular plate 130.
Application of a technique for correcting the tilting of No. 6 is conceivable (see Patent Document 3). This FIG.
The annular plate 130 shown in (a) to (b) is a long hole in which the support hole 131 extends in the circumferential direction, and after engaging the support shaft 106 before correction to the one end 131a side in the circumferential direction of the support hole 131, By rotating the support shaft 106 with respect to the carrier 104 until the support shaft 106 is positioned on the other end 131b side in the circumferential direction of the support hole 131, the support shaft 10 is provided on the other end 131b side in the circumferential direction of the support hole 131.
6 postures (fall down) can be corrected. 12 (a) and 12 (b), parts corresponding to the components of the planetary gear device 100 of FIG. 8 are assigned the same reference numerals as those of the planetary gear device 100 of FIG. 8, and the planets of FIG. A description overlapping with the description of the gear device 100 is omitted.

Microfilm (see FIGS. 1 and 3) of Japanese Utility Model Application No. 01-103333 (Japanese Utility Model Application Publication No. 03-043148) Japanese Patent Laid-Open No. 11-132297 (refer to description of paragraph 0009) Japanese Unexamined Patent Publication No. 2009-287664 (see paragraph numbers 0006 to 0007, 0026 to 0028, FIG. 8, FIG. 11, and FIG. 12)

However, when the annular plate 130 manufactured separately from the carrier 104 is used to correct the inward tilt of the carrier 104 to the support shaft 106, the annular plate 13
It is necessary to newly secure an accommodation space of 0 in the gear case 101, and the planetary gear device 10
This causes a new problem that the size of the planetary gear device 100 is increased, the weight of the planetary gear device 100 is increased, and the product price of the planetary gear device 100 is increased.

Therefore, the present invention can suppress the falling of the support shaft of the carrier due to the injection molding so that a separate part (annular plate) for correcting the tilt of the support shaft of the carrier after the injection molding is unnecessary. An object of the present invention is to provide a mold for injection molding of a carrier for a planetary gear device.

The injection mold 2 for the planetary gear carrier 1 according to the invention of claim 1 is shown in FIGS.
(1) a first cavity portion 23 for forming a disk-shaped carrier body 3;
(2) The same number of support shafts 5 as the planetary gears 103 that rotatably support a plurality of planetary gears 103 meshing with the input-side sun gear 102, and the support shafts 5 projecting from one side surface 4 of the carrier body 3. And (3) a third cavity portion for forming an output-side sun gear 7 that protrudes from the other side surface 6 of the carrier body 3 and is located concentrically with the rotation center 8 of the carrier body 3. 32 (see FIG. 8). A portion of the first cavity portion 23 that forms the other side surface 6 of the carrier body 3 is a pinpoint gate 31 that opens into the first cavity portion 23, and the second cavity 6. The pinpoint gate 31 is formed so that a molten plastic can be injected toward the opening of the cavity portion 26 on the first cavity portion 23 side.

The carrier for a planetary gear device that is injection-molded by using the injection mold according to the present invention can suppress the tilting of the support shaft to such an extent that a separate part for correcting the tilting of the support shaft is unnecessary. As a result, the carrier for the planetary gear device that is injection-molded using the injection mold according to the present invention invites an increase in the size of the planetary gear device, an increase in the weight of the planetary gear device accompanying an increase in the number of parts, There will be no increase in the product price of the planetary gear unit.

It is sectional drawing of the metal mold | die for injection molding of the carrier for planetary gear apparatuses which concerns on 1st Embodiment of this invention. FIG. 2 is a cross-sectional view of an injection mold shown by cutting along line A1-A1 in FIG. It is a figure which divides | segments and shows the injection mold of FIG. 1 along the A2-A2 line | wire (moulding surface of a fixed mold and a movable mold), and is a front view of a fixed mold. It is a figure which shows the carrier for planetary gear apparatuses injection-molded with the metal mold | die for injection molding which concerns on 1st Embodiment of this invention. 4 (a) is a front view of the carrier, FIG. 4 (b) is a side view of the carrier, and FIG. 4 (c) is a cross-sectional view taken along line A3-A3 of FIG. 4 (a). FIG. FIG. 5A is a cross-sectional view of an injection mold for a planetary gear carrier according to a second embodiment of the present invention, and FIG. 5B is an enlarged view of a portion indicated by F in FIG. 5A. FIG. It is sectional drawing of the metal mold | die for injection-molding cut | disconnected and shown along the A4-A4 line | wire of Fig.5 (a). It is a figure which shows the carrier for planetary gear apparatuses injection-molded with the metal mold | die for injection molding which concerns on 2nd Embodiment of this invention. 7 (a) is a front view of the carrier, FIG. 7 (b) is a side view of the carrier, and FIG. 7 (c) is a cross-sectional view taken along line A5-A5 of FIG. 7 (a). FIG. It is a longitudinal cross-sectional view of the planetary gear apparatus using the conventional carrier. It is sectional drawing cut | disconnected and shown along the A6-A6 line | wire of FIG. It is sectional drawing of the metal mold | die for injection molding used in order to carry out injection molding of the carrier for the conventional planetary gear apparatus. It is a figure which shows the deformation | transformation state (falling of a support shaft) of the support shaft after the injection molding of the carrier for the conventional planetary gear apparatus, FIG.11 (a) is a front view of a carrier, FIG.11 (b) is a carrier. It is a side view. FIG. 12 is a diagram illustrating an application example of the technique for correcting the tilt of the support shaft of the carrier illustrated in FIG. 11, FIG. 12 (a) is a diagram from the front side of the carrier, and FIG. 12 (b) is FIG. It is sectional drawing cut | disconnected and shown along the A7-A7 line | wire of).

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a cross-sectional view showing an injection mold 2 of a planetary gear carrier 1 according to a first embodiment of the present invention. 2 is a cross-sectional view of the injection mold 2 cut along the line A1-A1 of FIG. FIG. 3 is a view showing the injection mold 2 shown in FIG. 1 divided along the line A2-A2 (mold-matching surfaces 21p and 22p of the fixed mold 21 and the movable mold 22). FIG. FIG. 4 shows a plastic planetary gear device carrier 1 injection-molded by the injection-molding mold 2 shown in FIGS. The planetary gear device carrier 1 shown in FIG. 4 can be used in place of the conventional carrier 104 in the planetary gear device 100 of FIG. 8, and will be described with reference to FIG. 8 for convenience of explanation. To do.

(Carrier for planetary gear device and injection mold thereof)
As shown in FIG. 4, a carrier 1 for a planetary gear device that is injection-molded by the injection-molding mold 2 of FIGS. 1 to 3 includes a disk-shaped carrier body 3 and one side surface 4 of the carrier body 3. And the output side sun gear 7 which protrudes from the other side surface 6 of the carrier body 3 (see FIG. 8).

Three support shafts 5 integral with the carrier body 3 are formed at equal intervals (at intervals of 120 °) in the circumferential direction of the circle 10 around the rotation center 8 of the carrier body 3. It protrudes from the side face 4 substantially parallel to the rotation center line 13. The support shaft 5 does not protrude parallel to the rotation center line 13 of the carrier body 3, and the support shaft 5 does not protrude from the carrier body 3.
The reason for projecting substantially parallel to the rotation center line 13 is that the deformation of the support shaft 5 and the like due to a difference in shrinkage after injection molding or the like (an error from the design value) is taken into consideration.

The output side sun gear 7 integrated with the carrier body 3 is formed so that the center axis 15 is concentric with the rotation center line 13 of the carrier body 3. The output-side sun gear 7 has a bottomed hole 17 along the rotation center line 13 from the front end surface 16 along the rotation center line 13 to a position corresponding to the other side surface 6 of the carrier body 3. Is formed. That is, the meat hole 17 is
The output side sun gear 7 is formed to have the same hole depth as the protruding length along the central axis 15.

As shown in FIGS. 1 to 3, the injection molding die 2 of the planetary gear device carrier 1 is formed with a cavity 20 for injection molding the planetary gear device carrier 1 shown in FIG. The injection mold 2 is roughly divided into a fixed mold 21 and a movable mold 22, and the fixed mold 21 and the movable mold 22.
A first cavity portion 23 that is a disk-shaped recess for forming the carrier body 3 is formed on the mold matching surfaces 21p and 22p. Note that the mold-matching surfaces 21p of the fixed mold 21 and the movable mold 22 are provided.
22p is formed so as to coincide with the upper end edge 25 of the outer peripheral chamfer 24 on the side surface 4 side of the carrier body 3.

The movable mold 22 (22a, 22b) is formed with a part of the first cavity part 23 described above (a part corresponding to the one side face 4 side of the carrier body 3) and a plurality of supports of the carrier 1 for the planetary gear device. The same number of second cavities 26 for forming the shaft 5 as the support shaft 5 are formed. The second cavity part 26 forms the round bar-like support shaft 5, so that the first cavity part 2
It is a round hole with a bottom that opens to 3. Further, the second cavity portion 26 is formed of the carrier body 3
The movable mold 22 is formed so as to be parallel to the center line 27 of the first cavity portion 23 corresponding to the rotation center line 13.

The fixed mold 21 is configured such that the cavity 20 is opened to the outside when the movable mold 22 is separated from the state in which the mold matching surface 21p is in close contact with the mold matching surface 22p of the movable mold 22 (the state of FIG. 1A). It has become. The fixed die 21 has a remaining portion of the first cavity portion 23 (a first cavity formed in the movable die 22) which is a disk-like recess for forming most of the carrier body 3 on the die-matching surface 21p side. The remaining part of the first cavity part 23 excluding a part of the part 23) is formed. The fixed mold 21 is a third cylindrical recess for forming the output-side sun gear 7.
The cavity portion 32 is formed so as to open to the first cavity portion 23. In addition, the fixed mold 21 has a shaft mold portion 33 corresponding to the hollow hole 17 of the output-side sun gear 7 and the third cavity portion 3.
2, the tip surface 33 a of the shaft mold portion 33 is positioned on the side surface 3 of the first cavity portion 23.
4 (portion corresponding to the other side surface 6 of the carrier body 3) is formed on the same plane.

The fixed die 21 is a pinpoint gate 31 that opens into the first cavity portion 23 on the side surface 34 of the first cavity portion 23 (the portion that forms the other side surface 6 of the carrier body 3), and The melted plastic (polyacetal, polyamide, polyphenylene sulfide (PPS) or other plastic, polyacetal, polyamide, P mixed with reinforcing fibers such as carbon fiber) toward the opening on the first cavity portion 23 side of the two cavity portion 26
Pinpoint gate 3 that can inject plastics such as PS
1 is formed in the same number as the second cavity portion 26. The pinpoint gate 31 is formed such that the center line 31a is concentric with the center line 26a of the second cavity part 26, and is equidistantly arranged on the circumference centered on the center 30 of the first cavity part 23. (120 ° intervals). In FIG. 1, the center line 26 a of the second cavity portion 26 and the center line 31 a of the pinpoint gate 31 are concentric. However, the molten plastic injected from the pinpoint gate 31 is the second cavity portion 26. The center line 26a of the second cavity portion 26 and the center line 31a of the pinpoint gate 31 may be shifted on the condition that they are directly filled inside.

In addition, the fixed mold 21 has the first cavity portion 23 after the movable mold 22 is separated (after the mold is opened).
In addition, an eject pin 35 for pushing out the injection molded product (planetary gear device carrier 1) remaining in the third cavity portion 32 from the first cavity portion 23 and the third cavity portion 32 is provided.

The fixed mold 21 and the movable mold 22 are divided into a plurality of blocks (21 according to the shape of the injection molded product.
a, 21b, 22a, 22b, 33...

(Injection molding of carrier for planetary gear unit)
In order to injection-mold the carrier 1 for a planetary gear device, as shown in FIG. 1, the mold-clamping surface 21p of the fixed mold 21 and the mold-matching surface 22p of the movable mold 22 are in close contact with each other, and a pinpoint gate The molten plastic is injected from 31 toward the second cavity portion 26.

The molten plastic injected from the pinpoint gate 31 fills the second cavity portion 26 and then flows into the first cavity portion 23. At this time, the second cavity portion 2
The molten plastic in 6 flows radially and evenly from the opening of the second cavity portion 26 into the first cavity portion 23. As a result, when the molten plastic injected from the pinpoint gate 31 contains reinforcing fibers, the orientation of the reinforcing fibers contained in the molten plastic flowing from the second cavity part 26 into the first cavity part 23 Are aligned along the circumferential direction of the opening of the second cavity portion 26.

When the inside of the first cavity part 23 is filled with the molten plastic injected from the pinpoint gate 31, the molten plastic in the first cavity part 23 flows into the third cavity part 32, and the third cavity part The inside of 32 is filled with the molten plastic flowing in from the first cavity portion 23.

(Effects obtained by the injection mold of this embodiment)
The planetary gear device carrier 1 injection-molded using the injection-molding mold 2 of the present embodiment is
The tilt of the support shaft 5 is significantly smaller than the tilt of the support shaft 106 of the carrier 104 (see FIG. 11) injection-molded using the conventional injection mold 120 (see FIG. 10) ( (See Table 1). As a result, the planetary gear device carrier 1 injection-molded using the injection-molding mold 2 of this embodiment is a separate component (annular plate 130) that corrects the tilting of the support shaft 106 of the conventional example shown in FIG. ) Is not required, leading to an increase in the size of the planetary gear device 100, an increase in the weight of the planetary gear device 100 due to an increase in the number of parts, and an increase in the product price of the planetary gear device 100.

Table 1 shows the tilting of the support shaft 5 of the carrier for planetary gear device 1 (the carrier of the present invention) 1 injection-molded using the injection-molding die 2 of the present embodiment, and the injection-molding die 120 of the conventional example. Is shown in comparison with the tilting of the support shaft 106 of the carrier 104 (conventional example carrier) that has been injection-molded using (see FIGS. 1, 4, 10, and 11). In Table 1, the carrier 1 of the present invention and the carrier 104 of the conventional example are injection-molded with PPS containing fibers. Further, in Table 1, the amount of displacement (ε) in the radial direction of the tip of the support shaft (5, 106) is + (plus) in the case of displacement (falling) inward in the radial direction of the carrier (1,104). ) And career (
1,104) in the radially outward direction (falling) was defined as-(minus).

In addition, as a fiber mixed in PPS, fibrous reinforcements, such as a whisker, glass fiber, and an aramid fiber, are used.

[Second Embodiment]
FIG. 5 is a sectional view showing an injection mold 2 of the planetary gear device carrier 1 according to the second embodiment of the present invention. 6 is a cross-sectional view of the injection mold 2 cut along the line A4-A4 in FIG. FIG. 7 shows a plastic planetary gear carrier 1 that is injection-molded by the injection-molding mold 2 shown in FIGS. In addition,
The planetary gear device carrier 1 shown in FIG. 7 can be used in place of the conventional carrier 104 in the planetary gear device 100 of FIG. 8 in the same manner as the planetary gear device carrier 1 shown in FIG. is there. Further, the injection mold 2 according to the present embodiment is the same as the injection mold 2 according to the first embodiment except for the shape of the second cavity portion 26. Further, the planetary gear device carrier 1 injection-molded by the injection-molding mold 2 according to the present embodiment is the same as the injection-molding mold 2 according to the first embodiment except for the shape of the support shaft 5. It is the same as the carrier 1 for the planetary gear set that has been injection molded. Therefore, in the injection mold 2 according to this embodiment, the same reference numerals are given to the same components as those of the injection mold 2 according to the first embodiment, and the first
A description overlapping with the description in the embodiment is omitted. Further, the planetary gear device carrier 1 injection-molded with the injection mold 2 according to the present embodiment includes the planetary gear device carrier 1 injection-molded with the injection mold 2 according to the first embodiment. The same reference numerals are given to the same components, and the description overlapping the description in the first embodiment is omitted.

That is, the injection mold 2 according to the present embodiment has a round bar shape extending along the center line 26a of the second cavity portion 26 in order to form the support shaft 5 of the planetary gear device carrier 1 in a hollow cylindrical shape. A meat removal pin 37 is integrally provided on the movable mold 22. The meat removal pin 37 is formed so that its tip end surface is slightly retracted into the second cavity portion 26 rather than the opening of the second cavity portion 26. By forming the lightening pin 37 in this way, the molten plastic injected from the pinpoint gate 31 can be reliably introduced into the second cavity portion 26. The meat removal pin 37 is integrated with the movable die 22 by press-fitting or screwing a metal bar formed separately from the movable die 22 into the movable die 22.
In FIG. 5, when the diameter of the lightening pin 37 is d0, d0 / d1 is 1/3 to 1
/ 2.

In the planetary gear device carrier 1 injection-molded by the injection molding die 2 according to this embodiment, the support shaft 5 is tilted by the support shaft 5 of the planetary gear device carrier 1 according to the first embodiment. It can be kept as small as falling (see Table 1).

In the present embodiment, the mode in which the tip end surface of the lightening pin 37 is slightly retracted from the opening of the second cavity portion 26 is illustrated, but the molten plastic injected from the pinpoint gate 31 is On the condition that the second cavity portion is directly filled, the tip end surface of the lightening pin 37 may be arranged at the same position as the opening of the second cavity portion 26 (position contacting the first cavity portion 23). Good.

1 ... Carrier for planetary gear unit 2 ... Mold for injection molding 3 ... Carrier body 4 ...
One side surface, 5... Support shaft, 6... The other side surface, 7... Output side sun gear, 8... Center of rotation, 23. Pinpoint gate, 32 ... 3rd cavity, 102 ... Input side sun gear, 103 ... Planetary gear

Claims (1)

A first cavity for forming a disk-shaped carrier body;
A second cavity portion that is the same number of support shafts as the planetary gears that rotatably support a plurality of planetary gears that mesh with the input-side sun gear, and that forms the support shaft protruding from one side surface of the carrier body;
A third cavity for projecting from the other side of the carrier body and forming an output-side sun gear concentrically with the center of rotation of the carrier body;
A mold for injection molding of a carrier for a planetary gear device having
In the portion of the first cavity portion that forms the other side surface of the carrier body,
It is a pinpoint gate that opens into the first cavity portion, and is capable of injecting molten plastic toward the opening portion of the second cavity portion on the first cavity portion side. The pinpoint gate was formed,
A mold for injection molding of a carrier for a planetary gear device.

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