JPH0440895Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mold for injection molding thermoplastic resin gears having a helix angle, and in particular, an injection mold for gears having a structure suitable for rotation extraction. It is related to.

[Prior Art] A conventional mold for injection molding a thermoplastic resin gear having a helix angle has a structure as shown in a cross-sectional view of a main part in FIG.

In the figure, a gear core 1 is used to mold the gear portion of a thermoplastic resin gear having a helix angle of a molded product 2, and is set within a main core 8. The main core 8 is used to mold parts other than the gear part of the molded product 2 and the end 4a of the rotary core shaft 4, and the sub core 3 corresponding to the main core 8 has a gate 3a for injecting resin. have. The rotary core shaft 4 uses its end portion 4a for molding the molded product 2, and receives rotational force from an intermediate gear 6 by a shaft drive gear 5, which is a spur gear secured by a key 5a, and rotates as necessary. The intermediate gear 6 is pivotally supported by the gear boxes 8a and 8b using an intermediate gear shaft 7, and rotational force is applied to the intermediate gear 6 by a motor (not shown). The tooth thickness of the intermediate gear 6 is thicker than that of the shaft drive gear 5, so that the intermediate gear 6 can move in the axial direction of the intermediate gear 6 while the shaft drive gear 5 is engaged. Note that a motor (not shown) and an intermediate gear 6 that provide rotational force to the rotating core shaft 4 are provided.
and the shaft drive gear 5 constitute a drive means.

Further, a male guide screw 9 is cut into the rotating core shaft 4, and is screwed into a female guide screw 10 disposed on the gearbox 8b. The distance that the rotary core shaft 4 moves in one rotation due to the screw engagement between the male guide screw 9 and the female guide screw 10, that is, the lead between the male guide screw 9 and the female guide screw 10 is the distance between the gear core 1 and the molded product 2. And the lead has been matched.

The gear injection mold configured as described above can be operated as follows.

First, resin is injected through the gate 3a of the sub-core 3 to harden the molded product 2, and then the intermediate gear 6 is rotated by a motor, which is used as rotation of the shaft drive gear 5 to rotate the rotary core shaft 4. .
The rotation of the rotating core shaft 4 is caused by the screw engagement between the male guide screw 9 and the female guide screw 10, so that the rotating core shaft 4 moves in the axial direction while meshing with the shaft drive gear 5 and the intermediate gear 6.

Therefore, the molded product 2 formed by injection through the gate 3a of the sub-core 3 can be rotated and extracted.

[Problems to be Solved by the Invention] However, the gear injection mold configured in the conventional manner has a lead between the male guide screw 9 and the female guide screw 10 and a lead between the gear core 1 and the molded product 2. It was necessary to match each other. Therefore, when molding a thermoplastic resin gear with a helix angle as the molded product 2, it is necessary to match the lead of the molded product 2 with the lead of the rotating core shaft 4 to be rotated. Each time the rotor core shaft 4 is different, the lead of the rotor core shaft 4 is matched with the lead of the molded product 2. Therefore, it is necessary to change the lead caused by the engagement between the male lead guide screw 9 and the female guide screw 10 of the rotating core shaft 4, and the lead caused by the engagement between the male guide screw 9 and the female guide screw 10 every time the lead of the molded product 2 changes. , lead guide male screw 9 and guide female screw 10 of rotating core shaft 4
It was a hassle to have to replace it.

In particular, in the case of resin speedometer drive gears for automobiles, multiple speedometer drive gears with different gear elements may be arranged on the same shaft in order to accommodate transmissions and differentials. When molding meter drive gears, even if the basic properties match, the entire injection mold for gears needs to be changed every time the 2nd lead of the molded product changes, and changing the mold will cause the molded product to change. This was a problem because it led to higher costs. In addition, a process of changing the mold was required for each molded product, which caused problems in workability.

Therefore, the present invention was made to solve the above problems, and the purpose is to provide an injection mold for gears that does not require replacing the entire injection mold for gears even if the lead of the molded product is changed. That is.

[Means for Solving the Problems] The injection mold for gears according to the present invention includes a core for molding the gear, a rotating core shaft, a driving means for applying rotational force to the rotating core shaft, and a drive means for applying rotational force to the rotating core shaft, and a lead selection means for moving the molded gear and rotating the molded gear.

[Operation] In the present invention, a rotational force is applied to the rotating core shaft by the driving means, and the rotating core shaft is moved in the axial direction by the same lead as the lead of the gear selected by the lead selection means and formed. Remove the rotation of the gear.

[Example] Fig. 1 is a cross-sectional view of a main part showing the structure of an injection mold for a gear according to a first example of the present invention. Also, the second
3 and 3 are explanatory views of the operation of the gear injection molding die according to the first embodiment of the present invention. In addition, in the figure, the fifth
The same reference numerals or symbols as the structural parts of the conventional gear injection mold shown in the drawings indicate the same or equivalent parts. In particular, regarding the gear injection mold according to the first embodiment of the present invention, only the configuration different from the conventional example will be described.

In the figure, the rotating core shaft 4 has a guide male screw 20 with a male thread cut, similar to the conventional example shown in FIG.
is formed. A female guide screw 22 is screwed into the male guide screw 20. The female guide screw 22 has a female thread cut on the inside of the cylinder and a male thread cut on the outside. Further, a female guide screw 21 having a female thread cut inside the cylindrical body is screwed onto the male screw side of the male and female guide screw 22. The guide female screw 21 is fixed to the gearbox 8b. That is, a male guide screw 20, which is a male screw cut into the rotating core shaft 4, is screwed together with a male and female guide screw 22, and the male and female guide screw 22 is screwed together with a female guide screw 21.

Further, a shaft screw hole 20a consisting of a pair of screw holes is formed in the rotating core shaft 4, and
A male and female guide screw hole 22a is formed in the male and female guide screw 22 at a location opposite to the shaft screw hole 20a of the rotating core shaft 4, which is a pair of screw holes having a diameter larger than the screw diameter of the shaft screw hole 20a. Further, the female guide screw 21 has a male and female guide screw 22.
A guide female screw hole 21a consisting of a pair of screw holes having a diameter larger than the screw diameter of the guide female and male screw hole 22a is formed at a location opposite to the pair of guide female and male screw holes 22a.

Shaft screw hole 20 of the rotating core shaft 4
A pair of first fixing screws 23 that are screwed into the shaft screw holes 20a are provided in the pair of guide female and male screw holes 22a of the guide female and male screws 22. Moreover, the screw hole 22 for the guide female and male screws of the guide female and male screws 22
A pair of second fixing screws 24 are provided in the pair of guide female screw holes 21a of the guide female screw 21 and the guide female screw holes 22a.

The gear injection molding die of this embodiment configured as described above can be operated as follows.

First, as shown in FIG. 2, using a pair of first fixing screws 23,
are inserted into the pair of female and male guide screw holes 22a of the male and female guide screws 22, and screwed into the shaft screw holes 20a of the rotating core shaft 4. Therefore,
The rotating core shaft 4 and the male and female guide screws 22 rotate together as one.

Here, after resin is injected through the gate 3a of the sub-core 3 and cured, the intermediate gear 6 is rotated by the motor constituting the driving means, and this is used as the rotation of the shaft drive gear 5 to drive the rotating core shaft 4. Rotate. The rotating core shaft 4 is rotated by the pair of first fixing screws 23, and the male and female guide screws 22 are integrated. Male screw 22 and guide female screw 2
1, the rotating core shaft 4 moves in the axial direction while maintaining engagement between the shaft drive gear 5 and the intermediate gear 6.

Therefore, the molded product 2 formed by injection through the gate 3a of the sub-core 3 can be rotated and extracted by the lead determined by the screw engagement between the male and female guide screws 22 and the female guide screws 21. .

Similarly, as illustrated in FIG.
Using the fixing screw 24, a pair of second fixing screws 24
is inserted into the pair of guide female screw holes 21a of the guide female screw 21, and screwed into the guide female screw screw holes 22a of the guide female screw 22. Therefore,
The male and female guide screws 22 and the female guide screws 21 are integrated. At this time, the rotation of the rotating core shaft 4 is controlled by the pair of second fixing screws 24. Since the female guide screw 21 and the male and female guide screws 22 are integrated, the female screw of the male and female guide screws 22 and the guide of the rotating core shaft 4 are controlled. Due to the screw engagement with the male screw 20, the rotating core shaft 4 moves in the axial direction while maintaining the engagement between the shaft drive gear 5 and the intermediate gear 6.

Therefore, in this case, the molded product 2 injected from the gate 3a of the sub-core 3 is inserted into the male guide screw 20 and the female guide screw 22 of the rotating core shaft 4.
It can be rotated and removed by the lead determined by the screw engagement with the female screw.

Therefore, the male guide screw 20 of the rotating core shaft 4 and the female screw of the female guide screw 22 are screwed together, and the lead when the male and female guide screw 22 is on the fixed side is integrated with the male guide screw 20 of the rotating core shaft 4. If the male screw of the male and female guide screw 22 and the female guide screw 21 are screwed together and the leads are different when the male and female guide screw 22 is on the fixed side, the first fixed screw 23 or the second
By selecting the fixing screw 24, the lead can be changed. Therefore, the rotary extraction leads can be made to match the two types of leads of the molded product 2.

In this embodiment, the lead selection means for rotating the molded gear is provided by the rotating core shaft 4.
A male and female guide screw 22 screwed together with a male guide screw 20 of
and a female guide screw 21 fixed to the side of the gearbox 8b which is screwed into the male and female guide screws 22 are arranged in multiple layers in the radial direction. You can also use more than one. In this case, it is possible to provide N+1 types of rotation extraction leads for the number N of female and male guide screws provided.

FIG. 4 is a sectional view of essential parts showing the structure of an injection mold for gears according to a second embodiment of the present invention. In addition, in the figure, the same reference numerals or symbols as the structural parts of the gear injection mold of the conventional example and the first embodiment shown in FIG.
Indicates the same or equivalent part. In particular, regarding the gear injection molding die of the second embodiment of the present invention, only the configuration different from the first embodiment will be explained.

In the figure, the first guide male screw 30 and the second guide
The male screws 40 are screws with different leads disposed on the same central axis of the rotating core shaft 4. The split female guide screw 31 is a female screw that can be screwed into the first male guide screw 30 and is divided into a plurality of pieces, each half or less in size, and in the embodiment shown in FIG. 4, it is divided into two pieces. Further, the rod 32 has the guide split female screw 31 fixed to one end, a suction core 33 fixed to the other end, and is inserted into the solenoid 34.
The suction core 33 is biased by a spring 35 in a direction in which the guide split female screw 31 is separated from the first male guide screw 30. When the solenoid 34 is energized, the attraction core 33 is attracted against the elastic force of the spring 35, and the guide split female screw 31 moves in the direction in which it engages with the first guide male screw 30.

Similarly, the guide split female screw 41 is a female screw that can be screwed into the second guide male screw 40, and is divided into a plurality of pieces of 1/2 or less. Further, the rod 42 has the guide split female screw 41 fixed to one end, a suction core 43 fixed to the other end, and is inserted into the solenoid 44. The suction core 43 is biased by a spring 45 in a direction in which the guide split female screw 41 is separated from the second guide male screw 40 . When the solenoid 44 is energized, the attraction core 43 is attracted against the elastic force of the spring 45, and the split female guide screw 41 moves in the direction in which it engages with the second male guide screw 40.

The gear injection molding die of this embodiment configured as described above can be operated as follows.

First, in accordance with the lead of the molded product 2, the first guide male screw 30 or the second guide male screw corresponding to the lead
Select the lead of the male screw 40. Here, it is assumed that the lead of the first male guide screw 30 matches the lead of the molded product 2.

Therefore, the solenoid 34 is energized to attract the attraction core 33 against the elastic force of the spring 35, and the guide split female screw 31 is engaged with the first guide male screw 30.

Here, after resin is injected through the gate 3a of the sub-core 3 and the molded product 2 is cured, the intermediate gear 6 is rotated by the motor constituting the driving means, and this is used as the rotation of the shaft drive gear 5. The rotating core shaft 4 is rotated. The rotation of the rotary core shaft 4 is moved in the axial direction by the first male guide screw 30 that meshes with the split female screw 31, and the rotary core shaft 4 moves in the axial direction while the shaft drive gear 5 and the intermediate gear 6 are meshed.

Therefore, the molded product 2 formed by injection through the gate 3a of the sub-core 3 can be rotated and extracted by the lead determined by the screw engagement between the guide split female screw 31 and the first guide male screw 30. .

Similarly, when the solenoid 44 is excited to attract the attraction core 43 against the elastic force of the spring 45 and the guide split female screw 41 is engaged with the second guide male screw 40, the guide split female screw 41 The molded product 2 can be rotated and extracted by the lead determined by the screw engagement between the guide and the second male screw 40.

Therefore, the guide first male screws 3 with different leads arranged on the same central axis of the rotating core shaft 4
0 or the guide split female screw 31 or the guide split female screw 41 that meshes with the second guide male screw 40,
Selectively match the lead of molded product 2,
can be rotated and extracted.

In the embodiment shown in FIG. 4, the lead selection means for rotating and extracting the formed gear is a first male guide screw 30 or a second guide male screw with different leads arranged on the same central axis of the rotating core shaft 4. Male screw 40
However, when implementing the present invention, pairs of guide split female screws that engage with many male guide screws are additionally provided. May be placed.

In this manner, the injection mold for gears of each of the above embodiments provides rotational force to the auxiliary core 3 for molding the gear, the cores such as the gear core 1, the end portion 4a of the rotating core shaft 4, and the rotating core shaft 4. A driving means consisting of a motor, an intermediate gear 6, and a shaft drive gear 5, and a male and female guide screw 22 that is screwed into a male guide screw 20 of the rotary core shaft 4 that moves the rotary core shaft 4 in the axial direction and rotates and extracts the formed gear. and a guide female screw 21 fixed to the gearbox 8b side which is screwed into the guide male and female screw 22,
The lead selection selection means arranged in multiple layers in the radial direction, or the guide first male screw 3 with different leads.
0 or the second guide male screw 40 and the guide split female screw 31 or the guide split female screw 41 are arranged on the same central axis of the rotating core shaft 4.

The lead selection means includes the male and female guide screws 22 and the female guide screws 21 fixed to the gearbox 8b to which they are screwed, arranged in multiple layers in the radial direction. Since the screws are made of different threaded parts, the length direction of the rotating core shaft 4 of the gear injection mold can be shortened, and the first guide male screw 30 or the second guide male screw with different leads can be shortened. The lead selection selection means in which the guide split female screw 31 or the guide split female screw 41 that engages with the male screw 40 is disposed on the same central axis of the rotating core shaft 4 is longer in the length direction of the rotating core shaft 4, but core shaft 4
diameter can be made smaller.

Further, when carrying out the present invention, the lead selection means for rotating and extracting the molded gear includes the lead selection means arranged in multiple layers in the radial direction and the rotary core shaft 4 arranged on the same central axis. The lead selection selection means are combined with each other to shorten the length of the rotary core shaft 4 and to reduce the length of the rotary core shaft 4.
The diameter of can be reduced.

Note that the core for forming the gear and the rotating core shaft of the above embodiment consist of the auxiliary core 3 for forming the gear, the core such as the gear core 1, and the end portion 4a of the rotating core shaft 4. In this case, the molded product 2 having a gear portion having a helical angle may be molded using a core and a rotating core shaft, and as a result, the molded product 2 may be rotated and punched.

Further, the driving means for applying rotational force to the rotating core shaft in the above embodiment is composed of a motor, an intermediate gear 6, and a shaft drive gear 5, but when implementing the present invention, it is limited to the above configuration. Instead, any means that applies rotational force to the rotating core shaft may be used.

[Effects of the invention] As described above, the injection mold for gears of the present invention includes a core for molding a gear, a rotating core shaft, a driving means for applying rotational force to the rotating core shaft, and a drive means for applying rotational force to the rotating core shaft in the axial direction. The drive means applies rotational force to the rotating core shaft to select the same lead as the lead of the gear selected by the lead selection selection means. As a result, the rotating core shaft can be moved to walk on its axis, and the formed gear can be rotated and extracted.

Therefore, even if there is a change in the lead of the molded product, depending on the type of lead selected by the lead selection means,
Because it can handle the lead of the molded product, it can be used without replacing the entire gear injection mold, and changing the mold does not increase the cost of the molded product, and there is no need to change the mold for each molded product. Therefore, the workability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main parts showing the structure of the injection mold for gears according to the first embodiment of the present invention, and FIGS. 2 and 3 are the injection molds for gears according to the first embodiment of the present invention. 4 is a cross-sectional view of the main part showing the structure of the injection mold for gears according to the second embodiment of the present invention, and FIG. 5 is a cross-sectional view of the main parts showing the structure of the conventional injection mold for gears. It is a diagram. In the figure, 2...molded product, 3...sub-core, 4
... Rotating core shaft, 5 ... Shaft drive gear, 8 ... Main core, 20 ... Guide male screw, 21 ...
...Female guide screw, 22...Male and female guide screw, 30...
Guide first male screw, 40... Guide second male screw, 31
...Guiding split female screw, 41...Guiding split female screw,
It is. In addition, the same reference numerals and symbols in the figures are
Indicates the same or equivalent part.

Claims (1)

[Claims for Utility Model Registration] (1) A core for forming a gear, a rotating core shaft, a driving means for applying rotational force to the rotating core shaft, and a drive means for moving the rotating core shaft in an axial direction to remove rotation from the formed gear. An injection mold for a gear, characterized in that it is equipped with a lead selection means. (2) The gear according to claim 1, wherein the lead selection means comprises a threaded portion formed in the radial direction of the rotating core shaft and having different stages of leads. Injection mold for. (3) The utility model registration method according to claim 1, wherein the lead selection means comprises a threaded portion for differentiating a plurality of leads disposed in the direction of the central axis of the rotating core shaft. Injection mold for gears. (4) The lead selection means includes a threaded portion formed in the radial direction of the rotary core shaft that has different leads, and a screwed portion that has different leads arranged in the central axis direction of the rotary core shaft. The injection mold for gears according to claim 1 of the utility model registration claim, characterized in that the mold comprises: