JPS63103005A - Molding device for helical gear - Google Patents

Abstract

PURPOSE:To provide a molding device for a helical gear with which the simplification of the construction, the extended life of dies, etc., are attained by fixing an upper punch and providing helical tooth grooves to a part of an upper punch except the freely slidably fitting part thereof to either one of inner periphery of dies or outer periphery of a core. CONSTITUTION:After raw material powder M is packed into a space of a die 101, the upper punch 103 is lowered as shown in the right half part of the figure. As a result, the punch 103 is fitted into the space of the die 1 and is fitted to the upper end part 102a of a core 102, by which the raw material powder M is compressed between said punch and a lower punch 104 and a molding M' is formed. An inside lower punch 110 is slightly lowered while said punch is meshed and guided with the helical tooth grooves 102b of the core 102 and is kept rotated. An outside lower punch 111 is also rotated while said punch is meshed and guided with the helical tooth grooves 110b of the punch 110. The molding M' having a through-hole 118a in the central part and having helical teeth on the inner peripheral faces of a large diameter hole part 118b and small diameter hole part 118c respectively is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an improvement in a forming device for a sintered metal helical gear.

(Prior art) As an apparatus for forming a helical gear made of sintered metal having helical teeth on the circumferential surface with different diameters, for example, the Japanese Patent Publication No. 4B-2
A method for frying is known in Japanese Patent No. 9900. This device consists of a die, a core, an upper punch, and a lower punch, and the lower punch is divided into an inner lower punch and an outer lower punch that are formed coaxially, and the raw material powder supplied into the die is ,
By compressing between the lower punches, an irregular two-stage or three-stage helical gear is formed.

(Problem to be Solved by the Invention) However, in the above device, the upper punch is provided with a diagonal tooth groove, and when the upper punch is lowered to the upper surface of the die, the diagonal tooth groove is formed on the die or the core. As the upper punch engages with the tooth grooves and applies pressure while rotating under the rotational force in the circumferential direction due to engagement guidance, a mechanism to smoothly rotate and support the upper punch is required. An accurate positioning mechanism is required between the die or the core, resulting in a complicated structure, high cost, and short mold life.

The present invention was made in order to solve the problems of the above-mentioned conventional example, and its purpose is to form a bevel gear forming device that can simplify the structure, reduce costs, and extend the life of the mold. The goal is to provide the following.

(Means for Solving the Problems) In order to achieve the above object, the present invention comprises a die, a core, an upper punch, and a lower punch, the lower punch being an inner lower punch and an outer lower punch formed coaxially. In a bevel gear forming device that forms gears each having bevel teeth on circumferential surfaces with different diameters by compressing raw material powder divided into two parts and supplied into a die between upper and lower punches, The upper punch is fixed, and a diagonal tooth groove is provided in a portion of either the die or the core excluding the portion that slidably fits into the upper punch.

(Function) In the present invention having the above-mentioned configuration, when compressing the raw material powder supplied into the die, the upper punch is slidably fitted into the die and the core to apply pressure without rotating. As a result, it is possible to form a bevel gear having helical teeth on circumferential surfaces having different diameters, but at this time, a portion where no helical teeth are formed is formed on one end surface of the bevel gear. However, this portion can be easily removed by cutting or the like.

(Example) Embodiments of the present invention will be described below based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of a molding apparatus according to the present invention, and FIG.
) is a side view of a molded body formed by the same molding apparatus, and FIG.

In Fig. 1, the left half shows the filling state of raw material powder M,
The right half shows the compressed state, where 1 is the die, 2 is the core, 3 is the upper punch, and 4 is the lower punch.

The die 1 is formed into an almost cylindrical shape, and the die 1 has a shape of a cylinder.
The inner peripheral surface of the die 1, excluding the upper end portion 1a into which the upper punch 3 fits, is partially attached by a predetermined axial length from a lower position slightly away from the upper end portion 1a. A diagonal tooth groove 1b is formed.

In addition, the core 2 is formed in a cylindrical shape, and the core 2 is formed into a cylindrical shape.
The upper end portion of the core 2 is placed in the center of the die 1 in order to form a through hole in the center of the molded body M'. positioned.

In addition, the upper punch 3 is formed in a cylindrical shape, and the outer peripheral surface thereof does not have the oblique tooth grooves that were conventionally provided.
It is fixed via a fixing member 9 to the lower surface of another goose set 8 which is installed above the goose set 5 so as to be movable up and down.
When compressing the raw material powder M in the die 1, the upper end portion la
It is slidably fitted inside and lowered. Therefore,
Since there is no need to lower the upper punch while engaging the oblique tooth grooves of the upper punch and the oblique tooth grooves of the die, there is no need to provide a positioning mechanism between the upper punch 3 and the die 1. . A hole 3a is provided in the center of the upper punch 3, and the core 2 is fitted into the hole 3a when the upper punch 3 is lowered into the upper end portion la.

Further, the lower punch 4 is configured by coaxially combining a cylindrical lower white punch 10 within a cylindrical lower outer punch 11, and the upper end portion of the lower outer punch 11 is located at an intermediate height of the die 1. The upper end portion of the inner and lower punches 10 is also located at the lower end portion, thereby forming a space (a space for filling the raw material powder M) having two steps inside the die 1. There is. Here, the inner and lower punch 10 is rotatably installed on another punch set 12 arranged between the punch sets 5 and 7 via a rolling bearing 13, and has a core 2 in a hole 10a in the center thereof. penetrates therethrough, and the diagonal tooth groove 10b meshes with the diagonal tooth groove 11a on the inner peripheral surface of the lower outer punch 11 on its outer peripheral surface.
is formed. In addition, the outer lower punch 11 is
/ It is rotatably installed on a support member 14 arranged between 5 and 12 via a rolling bearing 15, and a diagonal tooth groove 11b that meshes with the diagonal tooth groove 1b of the die 1 is formed on its outer peripheral surface. has been done. The support member 14 can be moved slightly downward against the elastic force of the spring 16. In the figure, 17 is a stopper.

Next, the operation of the above molding device will be explained.

First, as shown in the left half of FIG. 1, the space of the die 1 is filled with the raw material powder M, and then, as shown in the right half of the same figure, if the upper punch 3 is lowered, the upper punch 3 is inserted into the die. 1 and the core 2, and the raw material powder M
is compressed with the lower punch 4 to form a molded body M'.

At this time, the lower outer punch 11 is guided to mesh with the diagonal tooth groove 1b of the die 1, rotates and descends slightly, and the lower inner punch 1
゜ is guided to mesh with the diagonal tooth groove 11a on the inner circumferential surface of the lower outer punch 11 and rotates.

Thereafter, the molded body M' is taken out from the die 1, and the die 1 and the upper punch 3 are returned to the raw material powder filling position shown in the left half of FIG. 1 to complete one process.

In this way, as shown in FIG. 2 Tal, a molded body M of a helical gear having a through hole 18a in the center and helical tooth grooves on the outer peripheral surfaces of the large diameter part 18b and the small diameter part 18c, respectively. ′
is manufactured. As shown in FIG. 2(al), this molded body M' has a portion L8d of thickness t in which no bevel teeth are formed on one end surface, but if this portion 18d is removed by cutting, the portion L8d in FIG. The helical gear 18 shown in b) can be obtained.This cutting process is easy and the processing cost is low.

In the above embodiment, since no diagonal tooth groove is provided on the outer peripheral surface of the upper punch 3, the upper punch 3 may be fixed to the die set 8, and when the upper punch 3 descends and contacts the upper surface of the die 1, the upper punch 3 is tilted. Since there is no need to engage the tooth grooves, no problem occurs even if no positioning mechanism is provided between the upper punch 3 and the die 1.

Modified embodiments of the present invention will be described below with reference to FIGS. 3 to 5.

FIG. 3 is a longitudinal cross-sectional view of an apparatus for manufacturing a molded body M' of a helical gear 118 having helical teeth on its inner peripheral surface as shown in FIGS. The filling state of powder M is shown, and the right half shows the compressed state, 101 is a die, 102 is a core, 103 is an upper punch, and 104 is a lower punch.

The die 101 is formed into a substantially cylindrical shape and is fixed to the gusset 5.

Further, the core 102 is formed in a cylindrical shape, and is rotatably erected on the guisent 105 via a rolling bearing 119 . An upper punch 10 is provided on the outer peripheral surface of this core 102.
The upper end portion 102a into which the hole 103a of No. 3 is slidably fitted
Except for this portion, a diagonal tooth groove 102b is partially formed by a predetermined axial length from a lower position slightly away from the portion 102a.

Further, the upper punch 103 is formed in a cylindrical shape, and the inner circumferential surface thereof does not have the oblique tooth grooves that were conventionally provided. It is fixed to the lower surface of the core 102 via a fixing member 109, and when compressing the raw material powder M in the die 1, it is slidably fitted into the upper end portion 102a of the core 102 and lowered. The outer diameter of the upper punch 103 is set to match the inner diameter of the mold hole of the die 101.

In addition, the lower punch 104 is configured by coaxially combining an inner and lower punch 110, which is also cylindrical, within a cylindrical outer and lower punch 111, and the upper end portion of the inner and lower punch 110 is located at an intermediate height of the die 1. Located at 111
is also located at the lower end inside the die 1, thereby forming a space (a space filled with the raw material powder M) having two steps inside the die 1. Here, the inner and lower punches 110
is rotatably erected on the support member 114 via a rolling bearing 115, and the diagonal tooth groove 1 of the core 102 is formed on the inner peripheral surface of the support member 114.
A diagonal tooth groove 110a that meshes with 02b is formed, and a diagonal tooth groove 110b that meshes with a diagonal tooth groove 111a on the inner peripheral surface of the lower outer punch 111 is formed on its outer peripheral surface.

In addition, the outer lower punch 111 includes the guide sets 105 and 107.
It is erected on another guisef) 112 located between. Note that the support member 114 can be moved slightly downward against the elastic force of the spring 116.

Next, to explain the operation of the above-mentioned forming apparatus, as shown in the left half of FIG. 3, the space of the die 101 is filled with raw material powder M, and then, as shown in the right half of the same figure, the upper punch 103 is lowered. For example, the upper punch 103 fits into the space of the hataisu 1, and also fits into the 1 leakage portion LO2a of the core 102,
The raw material powder M is compressed between the lower punch 104 and a molded body M'
to form. At this time, the inner and lower punches 110
The lower outer punch 111 is guided to mesh with the diagonal tooth groove 102b of the lower white punch 110 and rotates while slightly lowering.

In this way, as shown in FIG. 4, a helical gear having a through hole 118a in the center and helical teeth on the inner peripheral surfaces of the large diameter hole 118b and the small diameter hole 118c is formed. A body M' is produced. This molded body M' is also shown in Fig. 4 (
As shown in FIG. 1, a portion 118d in which no helical teeth are formed is formed on one end surface, but by cutting this portion 118d, a helical gear 118 shown in the same figure (bl) can be obtained.

In the above embodiment, since no diagonal tooth groove is provided on the inner circumferential surface of the upper punch 103, the upper punch 103 may be fixed to the die set 108, and the upper punch 103 may be lowered to cut the die 1.
Since there is no need to engage with the oblique tooth groove 102b of the core 102 when it comes into contact with the upper surface, no problem will occur even if no positioning mechanism is provided between the upper punch 103 and the core 102. .

As shown in FIG. 5, the lower white punch 110 is fixed to a support member 114', and the lower outer punch 111 is rotatably supported on the Daicera 112' via a rolling bearing 115'. However, it has the same functions and effects as those shown in FIG.

In the above embodiment, a forming device for a helical gear having helical teeth on two surfaces with different diameters was shown, but it goes without saying that the present invention can also be applied to a forming device for a helical gear having helical teeth on three or more surfaces. be.

(Effects of the Invention) As is clear from the above description, according to the present invention, the upper punch is fixed, and a portion where the upper punch is slidably fitted is provided on either the inner periphery of the die or the outer periphery of the core. Since a diagonal tooth groove is provided in the removed part, there is no need to provide a positioning mechanism between the upper punch and the die or core, simplifying the structure, reducing costs and extending mold life. It is possible to aim for In addition, on one end surface of the molded body,
Although there is a portion where the diagonal teeth are not formed, this portion can be easily removed by cutting, etc., and the cost for cutting, etc. is low, so it does not pose a problem.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a molding apparatus according to the present invention, and FIG.
1 is a side view of a molded body molded by the same molding device, FIG. 3(b) is a helical gear obtained from the same molded body, and FIG. Figure 4 t
a+ is a cross-sectional view of a molded body molded by the same molding device;
The same figure (bl is a helical gear obtained from the same molded body, and FIG. 5 is a longitudinal cross-sectional view of a molding apparatus according to yet another modified embodiment of the present invention. Explanation of symbols 1.101...Dice 2 ,102...core 3
．． 103... Upper punch 4, 104... Lower punch 10, 110... White lower punch 11. 111... Lower outer punch la, 102a... Portion lb where oblique tooth groove is not formed, 102b. ...Oblique tooth groove 8,108...Guicent 9.109...Fixing member Fig. 1 Fig. 2 1 jab t8a Fig. 3 Fig. 4 naa naa Fig. 5

Claims (1)

[Claims] Consisting of a die, a core, an upper punch, and a lower punch, the lower punch is divided into an inner and lower punch and an outer and lower punch formed coaxially, and the raw material powder supplied into the die is divided between the upper and lower punches. In a helical gear forming device that forms gears having helical teeth on circumferential surfaces with different diameters by compression, the upper punch is fixed, and the upper punch is attached to either the die or the core. 1. A forming device for a helical gear, characterized in that a helical tooth groove is provided in a portion of the helical gear excluding the portion that is slidably fitted into the helical gear.