JP2002143977A - Gear forming method and device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely secure strength of a gear, to improve the yield of material, to simplify a forming device itself, and to reduce processing time as much as possible. SOLUTION: The gear forming device 10 is composed of a fixed part 14 and a movable part 16. The fixed part 14 is equipped with a center guide 24, a lower punch 40 freely rotatable around the outer peripheral surface of the center guide 24, and a die 84 for which a tooth profile forming part 86 is carved and provided on the inner periphery. The angle θ of the tooth 87 of the tooth profile forming part 86 is set in the range of 30 deg.<θ<45 deg. relative to the axial direction. The movable part 16 is equipped with a mandrel 96, an insert punch sleeve 98 to be fitted to the mandrel 96, and an upper punch 112 freely slidable on the outer peripheral surface of the insert punch sleeve 98.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear forming method and apparatus for forming gears by hot forging or cold forging.

[0002]

2. Description of the Related Art For example, as one method of manufacturing a helical gear used for a transmission of an automobile, a hot forged preform 12 as shown in FIG. There is a method for manufacturing the helical gear 130 shown in FIG. In this case, a helical tooth profile 132 inclined at a predetermined angle with respect to the axial direction is formed on the side peripheral wall of the helical gear 130.

[0003]

However, in the manufacturing method according to the prior art, when the helical tooth profile 132 is formed by cutting the hot-forged preform 12 by a cutter. In some cases, the torsion line (the flow of the fiber structure due to plastic deformation) generated in the preform 12 is cut by the cutter. As a result, there is a problem that the strength of the manufactured helical gear 130 is remarkably reduced, and that the material yield is deteriorated due to chips generated during cutting.

[0004] The present invention has been made in view of such problems, and by manufacturing various gears such as helical gears and spur gears without performing machining with a cutter or the like, the strength of the gears can be ensured. It is an object of the present invention to provide a gear forming method and a gear forming method which can secure the material yield, improve the material yield, and reduce the manufacturing cost.

[0005]

According to the present invention, a gear material is placed on one end of a lower punch having external teeth, a mandrel is inserted into the gear material, and an insert punch sleeve and an upper punch are used. A first step of pressing the gear blank, and releasing the pressing force of the insert punch sleeve against the gear blank to separate the insert punch sleeve from the gear blank; and further pressing the gear blank by the upper punch. A second step of flowing the gear material into a tooth forming section formed in a die in which the external teeth mesh with each other to form a tooth section of the gear; and rotating the lower punch under the action of a knockout punch. A third step of moving and releasing the gear from the die.

In the second step, for example, a helical tooth profile can be formed on the gear material. Alternatively, a spur tooth portion may be formed.

Further, the present invention provides a center guide, a knockout punch, a lower punch rotatably disposed on an outer peripheral surface of the center guide, and a tooth forming shape meshing with external teeth formed on the lower punch. A die having a portion, and a mandrel, an insert punch sleeve fitted to the mandrel, and an upper punch slidable on an outer peripheral surface of the insert punch sleeve are provided so as to face the die. The knockout punch, the mandrel, and the upper punch are connected to a first drive mechanism, a second drive mechanism, and a third drive mechanism, respectively, and the insert punch sleeve and the insert punch sleeve are inserted while the mandrel is inserted into a gear material. By pressing the gear material with the upper punch, the tooth profile of the gear is formed, and the second drive mechanism and the third drive are formed. The mandrel by operation mechanism,
After the insert punch sleeve and the upper punch are integrally separated from the gear, the knockout punch is moved under the driving action of the first drive mechanism, whereby the lower punch is rotated to move the gear. Is released from the die.

According to the present invention, it is possible to manufacture a gear from a gear material without performing machining with a cutter or the like, thereby preventing erroneous cutting of a forging line generated in a forged product. As a result, the strength of the gear after molding can be ensured, and the generation of chips during gear molding can be avoided as much as possible, so that the material yield can be improved and the manufacturing cost can be reduced. You.

When the gear is released from the die after the gear is formed from the gear material, the insert punch sleeve is fitted to the mandrel for centering the gear material. By driving the drive mechanism 3 in synchronization, the mandrel, the insert punch sleeve, and the upper punch can be integrally separated from the gear. Therefore, for example, there is no need to provide a dedicated pin for moving the mandrel or a drive mechanism for moving the pin. Therefore, before the gear is formed from the gear material and the gear is released from the die,
The gear can be formed only by installing three drive mechanisms for moving the insert punch sleeve, the upper punch, and the knockout punch, respectively.

Further, when the teeth of the tooth-forming part are inclined with respect to the axial direction, that is, when the teeth are formed in a helical shape, the angle θ of the tooth of the tooth-forming part with respect to the axial direction is set to three.
By setting the angle within the range of 0 ° <θ <45 ° and increasing the angle θ within the range of 30 ° <θ <45 °,
The contact area between the teeth of the formed gear can be made as large as possible. Therefore, for example, when a predetermined load is applied to the gear, the larger the contact area between the teeth is, the smaller the load applied per unit area becomes. As a result, the life of the gear can be extended, and the generation of the meshing noise between the teeth can be reduced as much as possible.

Moreover, in this case, the load on the teeth constituting the gear can be reduced to prevent a decrease in the strength of the teeth. For example, when the gear formed according to the present invention is used in a transmission for an automobile, Thus, the gear width can be reduced, and the transmission itself can be downsized. That is, since the angle θ of the first tooth forming portion with respect to the axial direction of the teeth can be set to a desired angle within the range of 30 ° <θ <45 ° according to the purpose, the degree of freedom in design is improved.

[0012] The teeth of the tooth forming portion may be formed parallel to the axial direction. In this case, the teeth are used to form the teeth of the spur gear.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a gear forming method according to the present invention will be described in detail with reference to the accompanying drawings, showing preferred embodiments in relation to a gear forming apparatus.

FIG. 1 is an explanatory longitudinal sectional view of a gear forming apparatus according to the present embodiment, which is partially omitted. This gear forming device 10
Is obtained by forging a ring-shaped preform (hereinafter also referred to as a gear material) 12 shown in FIG.
(See FIG. 11)
4 and a movable portion 16 (see FIG. 1).

The fixing portion 14 has a gantry 18. The gantry 18 has a first concave portion 20 formed at a substantially central portion thereof and a substantially concave portion formed radially outward with respect to the first concave portion 20. A second concave portion 22 having a rectangular shape is included. A substantially cylindrical center guide 24 is erected within the first recess 20 so as to extend upward in FIG. 1 from the first recess 20, and a claw portion surrounds the center guide 24. A first holder 30 including a main body 26 and a main body 28 is fixed on a first annular convex portion 32 formed between the first concave portion 20 and the second concave portion 22. The center guide 24 has its peripheral surface in contact with the claw portion 26, and a gap 34 is formed between the center guide 24 and the main body 28 so as to go around the center guide 24.

A plurality of substantially cylindrical knockout punches 36 are provided concentrically around the center guide 24 so as to penetrate the gantry 18, the claw portions 26, and the gap portions 34. The knockout punch 36 is centered by the center guide 24, and an annular spacer 38 mounted on the claw portion 26 of the first holder 30 is fixed to one end of the knockout punch 36, and The other end of the knockout punch 36 is connected to a first driving mechanism (not shown) at a lower part in FIG. Further, on the spacer 38, a lower punch 40 that can rotate around the outer peripheral surface of the center guide 24 is placed. In FIG. 1, the lower punch 40 is formed such that a lower portion is formed as a thick portion 42 and then an upper portion is formed as a thin portion 46 via a tapered portion 44. Helical external teeth 48 are engraved on the outer periphery of the distal end of the thin portion 46. Therefore, under the action of the first drive mechanism, the knockout punch 36 can move up and down in the vertical direction,
The lower punch 40 is also vertically movable via the spacer 38.

As shown in FIG. 2, gas dampers 54 are provided at the four corners of the second recess 22 at predetermined intervals from the axis of the center guide 24. A disk-shaped set plate 58 is fixed to the rod 56 of the gas damper 54 (see FIG. 1). As can be understood from FIG. 1, a coil spring 64 is interposed so as to surround the first annular projection 32, the first holder 30, and the knockout punch 36.

An annular bulging portion 68 is formed on a second annular convex portion 66 formed radially outward of the second concave portion 22 so as to cover the gas damper 54 and the set plate 58. Is fixed.
The outer peripheral surface 74 of the second holder 70 projects radially outward from the outer peripheral surface 72 of the gantry 18.

Further, an annular guide member 78 is attached to an annular flat portion 76 formed on the upper portion of the set plate 58, and a spacer 80 surrounding the lower punch 40 is rotated on the guide member 78. It is placed freely. A die 84 is fixed to the upper portion of the spacer 80, and a concave portion 82 having a tapered portion 81 is formed at the upper center of the die 84. A tooth forming portion 86 for forming the helical tooth portion 132 (see FIG. 11) of the helical gear 130 in communication with the concave portion 82 is formed on the die 84 (see FIG. 3). As shown in FIG. 3, the teeth 87 of the tooth forming portion 86 are inclined at an angle θ with respect to the axial direction and are engraved at equal intervals over the entire circumference. In the present embodiment, it is preferable that the angle θ is set in a range of 30 ° <θ <45 °.

An annular third holder 88 is fixed to the upper portion of the second holder 70, and a gas damper 54 is provided.
The second stopper portion 92 provided on the die 84 in the radial direction of the die 84 is directed inward in the radial direction of the third holder 88 by the elastic force of the third holder 88. The first stopper portion 90 provided on the holder 88 is engaged.
A fourth holder 93 is fitted to the outer peripheral surfaces 72, 74, 89 of the gantry 18, the second holder 70, and the third holder 88, respectively.

As shown in FIG. 1, the movable portion 16 includes a rod 94, a substantially cylindrical mandrel 96 fixed to a substantially central portion of one end of the rod 94, and an insert fitted to the mandrel 96. And a punch sleeve 98. The mandrel 96 is for centering the gear blank 12 when forging the gear blank 12. The outer peripheral surface of the insert punch sleeve 98 has a first linear portion 100 and a first linear portion 10 from below in FIG.
First inclined at a predetermined angle in a direction away from the axis from 0
, A second linear portion 104 extending in the axial direction from the first taper portion 102, and a second linear portion 1
It comprises a second tapered portion 106 inclined at a predetermined angle in a direction away from the axis with respect to the axis, and a third linear portion 108 extending from the second tapered portion 106 in the axial direction. Further, the other end of the rod 94 is connected to a second driving mechanism (not shown) in the upper part of FIG. Therefore, under the action of the second drive mechanism, the rod 94 can move vertically in the vertical direction.

Further, a spacer 110 is provided so as to surround the rod 94, and an annular upper punch 112 slidable on the outer peripheral surface of the insert punch sleeve 98 is provided on the bottom surface of the spacer 110. Punch 1 on this
The inner peripheral surface of the fourth straight portion 1 is shown in FIG.
14, a third tapered portion 116 inclined at a predetermined angle in a direction away from the axis from the fourth linear portion 114, and a fifth linear portion extending in the axial direction from the third tapered portion 116 118, and a fourth tapered portion 120 inclined at a predetermined angle in a direction away from the axis from the fifth linear portion 118.
A fifth tapered portion 122 conforming to the shape of the tapered portion 81 formed in the concave portion 82 is formed. As will be understood from FIG. 1, a first straight portion 100 formed on the insert punch sleeve 98, a fourth straight portion 114 formed on the upper punch 112, and a fourth straight portion 114 formed on the insert punch sleeve 98. 2 straight portion 104 and the upper punch 1
12 is in contact with the fifth straight portion 118 formed therein.

A fifth holder 124 for supporting and fixing the upper punch 112 in the direction of the spacer 110 is fitted on the outer peripheral surface of the upper punch 112.
A sixth holder 126 is externally mounted on the holder 124.
The spacer 110 and the sixth holder 126 are connected to a third driving mechanism (not shown) in the upper part of FIG. Therefore, under the action of the third drive mechanism, the spacer 110 and the sixth holder 126
Is vertically movable in the vertical direction. That is, the upper punch 112 is slidable vertically on the outer peripheral surface of the insert punch sleeve 98. The second drive mechanism (not shown) and the third drive mechanism (not shown) can be driven independently or synchronously.

The gear forming apparatus 10 according to the present embodiment
Basically, the structure is as described above. Next, the operation and effects of the present invention will be described in relation to the gear forming method.

First, a second drive mechanism and a third drive mechanism (not shown) are driven in synchronization with each other, so that the movable section 16 is separated from the fixed section 14 as shown in FIG. Then, the ring-shaped gear material 12 (see FIG. 10) is placed on the thin portion 46 of the lower punch 40. At this time, a part of the external teeth 48 engraved on the outer peripheral portion of the distal end of the thin portion 46 is engaged with the tooth forming portion 86 engraved on the inner peripheral portion of the die 84.

Thereafter, the second drive mechanism and the third drive mechanism (not shown) are driven synchronously to move the movable section 16 vertically downward so that the movable section 16 approaches the fixed section 14. (FIG. 4). In this case, the upper punch 1 is inserted into the tapered portion 81 formed in the concave portion 82 of the die 84.
The mandrel 96 is inserted into the gear material 12 while the fifth tapered portion 122 formed on the gear 12 comes into contact. Moreover, the gear blank 12 is pressed vertically downward by the insert punch sleeve 98 and the upper punch 112. Thereby, against the resilience of the gas damper 54,
The set plate 58, the spacer 80, and the die 84 are pressed vertically downward. Accordingly, the engagement of the second stopper 92 provided on the die 84 with the first stopper 90 formed on the third holder 88 is released, and the first stopper 90 and the first stopper 90 are disengaged. The second stopper portion 92
(FIG. 4). Further, since the lower punch 40 is rotatable around the outer peripheral surface of the center guide 24, the external teeth 48 further mesh with the tooth forming portion 86 (see FIG. 4).
At this time, a part of the meat of the gear blank 12 flows in the tooth forming section 86.

Next, a second drive mechanism (not shown) is driven to move the insert punch sleeve 98 vertically upward, and a third drive mechanism (not shown) is driven to further move the upper punch 112. Move vertically downward. As a result, the pressing action of the insert punch sleeve 98 against the gear blank 12 is released, and the second punch blank 98 is inserted between the gear blank 12 and the insert punch sleeve 98.
Is formed (see FIG. 5). At the same time, against the resilience of the gas damper 54, the set plate 58,
The spacer 80 and the die 84 are further pressed vertically downward, and the first gap 128 formed between the first stopper 90 and the second stopper 92 is expanded (FIG. 5).
reference). At this time, the flesh of the gear blank 12 further flows into the tooth forming section 86. At this time, the gear blank 12 rotates the outer peripheral surface of the mandrel 96 by a predetermined angle in a predetermined direction, and the tooth forming section 86 is engraved in a helical shape. The tooth forming part 86 is pressed while spirally flowing in the forming part 86. That is, a spiral force is applied to the die 84 in a direction away from the axis, but since the die 84 is pressed vertically downward by the upper punch 112, the die 84 The material 12 rotates by a predetermined angle in the rotation direction. In other words, the die 84 and the spacer 80 fixed to the bottom surface of the die 84
However, it rotates integrally on the guide member 78 about the shaft by a predetermined angle in the rotation direction of the gear blank 12. This allows
The helical tooth profile 132 of the helical gear 130 is formed (see FIG. 11).

Then, the second drive mechanism and the third drive mechanism (not shown) are driven synchronously to separate the movable section 16 from the fixed section 14 (see FIG. 6). That is, the mandrel 96, the insert punch sleeve 98, and the upper punch 1
12 will be separated from the helical gear 130 integrally. Thus, the set plate 58, the spacer 80, and the die 84 are opposed to the resilience of the gas damper 54.
Is released, and the second stopper portion 92 of the die 84 is moved to the first holder 88 of the third holder 88.
(See FIG. 6).

Thereafter, the knockout punch 36 is moved vertically upward under the action of a first drive mechanism (not shown). At this time, while the external teeth 48 of the lower punch 40 mesh with the tooth forming portion 86 of the die 84 via the spacer 38 fixed to the knockout punch 36, the lower punch 40
Rotates vertically upward. At this time, the die 84 is returned by a predetermined angle about a shaft in a predetermined direction by the engagement between the helical tooth profile 132 of the formed helical gear 130 and the tooth formation profile 86. That is, a state before the gear blank 12 is formed (a state shown in FIG. 1). As a result, the helical gear 130 is released from the die 84 (see FIG. 7).

The helical gear 130 is transported to the next step by a transport device (not shown), and is finally machined to a predetermined size and shape to be completed as a product.

In this embodiment, the case where a helical gear is formed has been described as an example. However, other gears, for example, a spur gear 142 having a spur tooth portion 140 as shown in FIG. 8 may be formed. Can also. In this case, FIG.
As shown in the figure, the teeth 15 formed parallel to the axial direction
A tooth forming profile 152 having zero may be used.

[0032]

As described above, according to the present invention,
Since the gear can be manufactured from the gear material without performing machining by a cutter or the like, it is possible to prevent the forging line generated in the forged product from being cut by mistake. This makes it possible to reliably ensure the strength of the gear after molding, and to avoid generation of chips during gear molding, thereby improving the material yield and simplifying the manufacturing process. In addition, the manufacturing cost can be reduced.

When the gear is released from the die after the gear is formed from the gear material, the insert punch sleeve is fitted to the mandrel for centering the gear material. By driving the drive mechanism 3 in synchronization, the mandrel, the insert punch sleeve, and the upper punch can be integrally separated from the gear. Therefore, for example, there is no need to provide a dedicated pin for moving the mandrel and a driving mechanism for moving the pin. Therefore, the gear is formed only by installing three drive mechanisms for moving the insert punch sleeve, the upper punch, and the knockout punch before the gear is formed from the gear material and the gear is released from the die. be able to.

Further, when the angle θ of the tooth forming portion formed on the die with respect to the axial direction of the teeth is set to an angle within the range of 30 ° <θ <45 °, the angle θ is set to 30 ° <θ <45 °. By increasing the diameter within the range, the contact area between the teeth of the formed gear can be increased as much as possible. For this reason,
For example, when a predetermined load is applied to the gear, the larger the contact area between the teeth is, the smaller the load applied per unit area becomes. A longer life can be achieved, and the generation of meshing noise between teeth can be reduced as much as possible. In addition, a reduction in the load on the gear teeth can prevent a decrease in the strength of the teeth. For example, when a gear formed according to the present invention is used in a transmission of an automobile, the gear width can be reduced,
As a result, downsizing of the transmission itself is achieved. That is, since the angle θ of the helical tooth forming portion with respect to the axial direction of the teeth can be set to a desired angle within a range of 30 ° <θ <45 ° according to the purpose, a specific effect of improving the degree of freedom in design is obtained. Can be

[Brief description of the drawings]

FIG. 1 is a partially omitted longitudinal sectional view showing a gear forming apparatus according to an embodiment.

FIG. 2 is an explanatory diagram viewed from the line II-II in FIG. 1;

FIG. 3 is a partially omitted enlarged longitudinal sectional view showing a die constituting the gear forming apparatus of FIG. 1;

4 is a partially omitted longitudinal cross-sectional view showing a state in which a gear material is pressed by an insert punch sleeve and an upper punch in the gear forming apparatus of FIG. 1;

5 is a partially omitted longitudinal cross-sectional view showing a state in which the gear blank is further pressed by the upper punch from the state shown in FIG. 4;

FIG. 6 is a partially-omitted longitudinal cross-sectional explanatory view showing a state in which a movable section is separated from a fixed section in the gear forming apparatus of FIG.

FIG. 7 is a partially omitted vertical cross-sectional explanatory view showing a state in which the helical gear after forging has been released from the die in the gear forming apparatus of FIG. 1;

FIG. 8 is a schematic overall perspective view of a spur gear.

FIG. 9 is a partially omitted enlarged longitudinal sectional view showing a gear forming portion on which teeth for forming a spur gear are formed.

FIG. 10 is a schematic overall perspective view of a preform (gear material).

FIG. 11 is a schematic overall perspective view of a helical gear.

[Explanation of symbols]

REFERENCE SIGNS LIST 10 gear forming device 12 gear material (preformed body) 24 center guide 36 knockout punch 40 lower punch 48 external teeth 86, 152 tooth forming part 87, 150
Tooth 96 ... Mandrel 98 ... Insert punch sleeve 112 ... Upper punch 130 ... Helical gear 132 ... Helical tooth profile 140 ... Spur tooth profile 142 ... Spur gear

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Takashi Kihara 8-1, Honcho, Wako-shi, Saitama Honda Motor Co., Ltd. Wako Factory, Saitama Manufacturing Co., Ltd. Shioya 14 Nichidai Ujitawara Plant (72) Inventor Yasuyuki Kondo Zenjiji Ujitawara-cho, Shizuki-gun, Kyoto Shiotani 14 Co., Ltd. Nichidai Ujitawara Plant F-term (reference) 4E087 AA02 AA10 BA20 CA14 CB01 CB03 EC12 EE02 EE10 EE10 HA02 HA04

Claims (7)

[Claims] A first material in which a gear material is placed on one end of a lower punch having external teeth, a mandrel is inserted into the gear material, and the gear material is pressed by an insert punch sleeve and an upper punch. And releasing the pressing force on the gear material by the insert punch sleeve to separate the insert punch sleeve from the gear material, and further pressing the gear material by the upper punch, so that the external teeth A second step of forming the tooth profile of the gear by flowing the gear material into a tooth forming profile formed on the mating die; and rotating the lower punch under the action of a knockout punch to move the gear into the die. A third step of releasing from the mold, and a method of forming a gear. 2. The gear forming method according to claim 1, wherein a helical tooth portion is formed on said gear material by said second step. 3. The gear forming method according to claim 1, wherein a spur tooth portion is formed on the gear material by the second step. 4. A center guide, a knockout punch,
A lower punch provided rotatably on the outer peripheral surface of the center guide, and a die having a tooth forming portion that meshes with external teeth formed on the lower punch; and a mandrel facing the die. And an insert punch sleeve fitted to the mandrel, and an upper punch slidable on the outer peripheral surface of the insert punch sleeve. The knockout punch, the mandrel, and the upper punch each have a first drive mechanism. Connected to the second drive mechanism and the third drive mechanism, and pressing the gear material by the insert punch sleeve and the upper punch while inserting the mandrel into the gear material, thereby forming the tooth profile of the gear. The mandrel, the insert punch sleeve, and the mold are formed under the driving action of the second drive mechanism and the third drive mechanism. After separating the upper punch integrally with the gear, the knockout punch is moved under the driving action of the first drive mechanism to rotate and move the lower punch to release the gear from the die. A gear forming device. 5. The gear forming device according to claim 4, wherein the teeth of the tooth forming portion are formed to be inclined with respect to the axial direction. 6. The gear forming apparatus according to claim 5, wherein the angle θ of the tooth forming portion with respect to the axial direction of the teeth is in the range of 30 ° <θ <45 °. 7. The gear forming apparatus according to claim 4, wherein the teeth of the tooth forming portion are formed in parallel with the axial direction.