JP2001340933A - Method for manufacturing gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a gear which can form a crowning tooth form based on a process in a simple composition. SOLUTION: A prepared hole j having a supporting wall 10 extending to a radial direction is formed, and a plurality of tooth forming regions 11, where the tooth form T is formed through a groove 12 in the axial direction, are provided and each tooth forming region 11 is formed into a shape with a radius difference so that a pressure of the tooth width direction center 11a becomes higher than the tooth width direction end section 11b when a form rolling die R is pressed to each tooth forming region 11, the form rolling die R is pressed all over each tooth forming region 11 and is relatively moved to form the crowning tooth form Tc, is separated with the groove 12 every tooth forming region 11, and the supporting wall 10 for the prepared hole j is removed in order to form a shaft hole piercing in the axial direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a gear for forming a tooth profile by pressing a rolling die against a rough material and causing relative movement thereof, and more particularly, to a tooth mold and / or a helical tooth provided with a crowning. The present invention relates to a method suitable for manufacturing a gear having a tooth profile.

[0002]

2. Description of the Related Art Conventional techniques for manufacturing gears include a cutting method of forming a tooth shape by cutting a rough material using a hobbing machine or the like, and a relative movement by pressing a rolling die against the rough material. There is a rolling method that creates a tooth profile. Tooth profiles formed by these cutting methods and rolling methods include spur gears in which the teeth are formed in a spa tooth shape parallel to the gear axis, and helical teeth in which the teeth are helical windings. There are helical gears and the like. Further, these gears have a tooth profile in which the tooth thickness is temporarily reduced from the central portion toward both side ends, and crowning is provided with an appropriate bulge in the direction of the tooth trace.

As a method of manufacturing the above-mentioned helical gear by a rolling method, for example, a method disclosed in Japanese Patent Application Laid-Open No. 8-323443 is known. In addition, in order to impart crowning to a tooth profile, cutting is generally performed so that the tooth thickness decreases for a while toward both side edges of the formed tooth profile, and is used in the above-described rolling method. Conventionally, the shape of the rolling dies is appropriately selected, such as by performing reverse crowning on the tooth surface of the rolling dies, or the pushing amount of the rolling dies relatively moved along the tooth shape is changed. ing.

[0004]

However, among the above-mentioned prior arts, in the case of manufacturing a gear by a cutting method, the ratio of the material actually forming the gear to the material of the coarse material (gear of the gear) is used. Weight / weight of the coarse material = net shape ratio), and there is a problem in that much of the material used is wasted. In addition, in this case, when crowning is applied to the tooth profile, it is not possible to simultaneously perform the shaping of the tooth profile and the application of the crowning, which increases the number of steps and requires equipment for performing each step. There was a problem of becoming.

[0005] Of the above-mentioned conventional techniques, when a tooth profile is created by a rolling method, when the coarse material rotates once by relative movement with a rolling die, the coarse material is sequentially formed. The pitch must be accurately determined so that the phase of the tooth form of the rolling die corresponds to the set tooth form. However, especially when forming a helical tooth profile, since tooth traces are a helical winding, the tooth shape formed on the rough material and the tooth shape of the rolling die simultaneously contact a plurality of times, so that pitch indexing is accurately performed. It was difficult to do. Furthermore, when crowning is imparted to a tooth profile by cutting after rolling, as in the case of the above-described cutting method, tooth shape molding and crowning cannot be performed simultaneously, and the number of processes increases. There is a problem that equipment for performing each step is required. When using a rolling die with a special shape, such as applying reverse crowning to the tooth surface of the rolling die, a general-purpose rolling die must be created for each gear to be manufactured. Therefore, there is a problem that the manufacturing cost cannot be reduced due to the lack of reliability.
Also, when changing the pushing amount of the rolling die relatively moved along the tooth shape, the control for relatively moving the rolling die along the tooth shape while changing the pushing amount is not performed. There was a problem that it was very difficult.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has as its object to provide a method of manufacturing a gear capable of forming a crowning tooth profile in a single process with a simple configuration. Another object of the present invention is to provide a method of manufacturing a gear capable of forming a tooth profile for a plurality of gears in one step. Further, the present invention provides a method for manufacturing a gear capable of preventing deformation of a gear due to pressing of a rolling die when a hole for inserting a gear shaft is formed in a coarse material. The purpose is to:

Further, the present invention has been made in view of the above-mentioned problems, and it is possible to accurately assign a tooth pitch with a simple configuration and to form a tooth shape of a plurality of gears. An object of the present invention is to provide a method for manufacturing a gear.

[0008] The invention according to the method for manufacturing a gear of claim 1 is as follows.
In order to achieve the above object, a method of manufacturing a gear for forming a tooth profile by pressing a rolling die against a coarse material and performing relative movement, wherein a portion of the coarse material having a tooth profile is formed by a rolling die. Is pressed so that the pressure at the center in the tooth width direction is higher than the end in the tooth width direction, and a rolling die is pressed against the coarse material to make a relative movement to form a crowning tooth profile. It is characterized by the following.

[0009] The invention according to a method for manufacturing a gear according to claim 2 is as follows.
In order to achieve the above object, in the invention according to claim 1, a plurality of portions where a tooth profile is formed are provided through grooves in the axial direction of the rough shaped material, and a crowning tooth profile is formed for each of the portions. The method is characterized in that a coarse material is cut off by the groove.

According to a third aspect of the invention, there is provided a gear manufacturing method,
In order to achieve the above object, the invention according to claim 1 or 2 is characterized in that a shaft hole having a wall extending in the radial direction is formed in the rough shaped material.

According to a fourth aspect of the present invention, there is provided a gear manufacturing method for forming a tooth profile by pressing a rolling die against a rough material to make a relative motion. In addition, a plurality of portions where the tooth profile is formed are provided in the axial direction of the rough material through grooves, and a rolling die is pressed over each of the portions.

According to the first aspect of the present invention, the portion of the coarse material forming the tooth profile is formed in such a shape that the pressure at the center in the tooth width direction becomes higher than the end in the tooth width direction when the rolling die is pressed. By simply pressing the rolling dies against this rough material and making it move relative to the rough material, the pressure of the rough material becomes higher at the center in the face width direction than at the end in the face width direction. Is formed.

According to a second aspect of the present invention, in the first aspect of the present invention, a plurality of teeth are formed through grooves, and a rolling die is pressed over each of the parts to form a roughened material. Since the plurality of tooth forms of the rolling die can be simultaneously brought into contact with each other, the pitch is accurately determined. And since the groove | channel is located between each site | part, the flow of the raw material of a rough material by the pressing of a rolling die is not obstructed. Further, a plurality of gears are manufactured by separating the coarse material having the crowning tooth profile at each portion with a groove.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the shaft hole having a wall extending in the radial direction of the coarse material is formed, so that the shaft hole of the gear can be easily formed later. Not only can the rolling die be pressed, but the wall supports against the pressing force when the rolling dies are pressed, so that the deformation of the crude material is prevented.

According to the fourth aspect of the present invention, by providing a plurality of portions in which the tooth profile is formed in the axial direction of the coarsely formed material through the groove, the rolling die is pressed over each portion.
Because the multiple tooth forms contact the rough material at the same time,
The pitch is accurately determined. And since the groove | channel is located between each site | part, the flow of the raw material of a rough material by the pressing of a rolling die is not obstructed.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a method for manufacturing a gear G according to the present invention will be described with reference to FIGS. 1 to 8 according to a case of manufacturing a spur gear Gs having a shaft hole J in which a tooth profile T is crowned. A detailed description will be given based on this. In the following description, the same reference numerals denote the same or corresponding parts.

In the method of manufacturing the gear G according to the present invention, a step of forming a pilot hole j having a support wall 10 extending in a radial direction (FIG. 1) and a tooth profile T formed through a groove 12 in an axial direction. A plurality of tooth profile forming portions 11 are provided, and a diameter difference d is provided so that the pressure at the center 11a in the tooth width direction becomes higher than the end portion 11b in the tooth width direction when the rolling die R is pressed against each tooth profile forming portion 11. Step of forming each tooth profile forming portion 11 into a shape (FIG. 2)
And forming a crowning tooth profile Tc by pressing the rolling dies R over each tooth profile forming site 11 to make a relative movement (FIG. 3). Separating each tooth profile forming site with a groove (FIG. 4) and penetrating in the axial direction A pilot hole j is formed to form a shaft hole J
(FIG. 5).

The material used to manufacture the gear G was initially
It is formed in a solid cylindrical shape (not shown). When manufacturing the gear G, first, the first rough shaped material W1 is formed by cold forging the material. First
As shown in FIG. 1, the rough shaped material W1 is formed with a pilot hole j having a bottom portion ja and extending toward the center in the axial direction from both end surfaces thereof. The support wall 10 is formed between the bottom portions ja of both pilot holes j. Further, a relief portion 13 is formed on the outer peripheral edge of the end face of the first rough material W1 to allow the flow of the material when the tooth form rolling is performed as described later. Note that the present invention is not limited to this embodiment, and when a single tooth profile forming portion 11 is provided, for example, FIG.
As shown by a dashed line, a single tooth profile forming portion 11 is provided,
The support wall 10 can be formed substantially at the center in the axial direction.
When the gear G to be manufactured has a shaft that protrudes in a boss shape without having the shaft hole J, the gear G is formed so as to protrude from both end surfaces of the crude material without forming a bottomed hole in the material. An axis can also be formed (not shown).

Next, the first molded member having such a shape is formed.
As shown in FIG. 2, a groove 12 for dividing the two tooth-formation portions 11 where the tooth shapes T are formed is formed in the center of the coarse material W1 in the axial direction on the outer peripheral surface of the coarse material W1. The diameter difference d is provided so that the diameter of the axial center 11a of the tooth profile forming portion 11 is larger than the diameter of the axial end portion 11b of each tooth profile forming portion 11, and the second coarse material is formed. In the second rough material, a relief portion 14 is also formed at an end 11b on the groove 12 side of each tooth profile forming portion 11. In addition, the groove 1 is formed in the first rough material.
2. Tooth profile forming portion 11 having diameter difference d, and relief portion 1
The step of forming 3 and 14 and forming the second rough material can be performed by cutting or the like.

Subsequently, a second molded member having such a shape is formed.
As shown in FIG.
While pressing the rolling die R over 1, 11
The rolling dies R are relatively moved so as to rotate the crude material around the axis. At this time, the prepared hole j of the second rough material W2 is supported by a shaft such as a center (not shown). In order to manufacture the spur gear Gs in this embodiment, the rolling die R has a tooth Rt formed parallel to the center axis CL of the gear to be manufactured, and the tooth Rt is formed. Unlike the crowning tooth profile Tc, the tooth thickness is not formed so as to differ depending on the tooth width direction, and a general shape is used. In addition, the rolling die R
Can use flat dies and round dies.
6 shows an initial state in which the rolling dies R are pressed against the tooth profile forming portion 11 above the central axis CL, and below the central axis CL, the rolling dies R are further pressed onto the tooth profile forming portion 11. The pressed state is shown.

Since the tooth difference R is provided at each tooth profile forming portion 11 of the second rough material W2, when pressing the tooth profile Rt of the general rolling die R, the center axis CL of FIG. As shown from above, first, the relatively large-diameter axial center 11a of the tooth profile forming portion 11 is in contact with the tooth form Rt of the rolling die R, and thereafter, as shown below from the central axis CL of FIG. Furthermore, the center 11a of the tooth forming portion 11 having a relatively large diameter in the axial direction, that is, in the tooth width direction, is filled with the bottom of the tooth form Rt of the rolling die R, and the pressure caused by the pressing increases. When the pressure is increased, the tooth shape Rt of the rolling die R acts to be pushed and expanded in the elastic deformation region. Therefore, the center of the tooth shape T formed in the tooth shape forming portion 11 in the tooth width direction is:
As shown by an arrow X in FIG. 7, it is formed so as to expand in the tooth thickness direction. When the rolling die R is further pressed, the tooth profile forming portions 11 are provided with relief portions 13 and 14 in which the material at the center 11a in the tooth width direction is formed at both ends as shown by an arrow Y in FIGS. 6 and 7. And the bottom of the tooth form Rt of the rolling die R is successively filled toward both ends 11b in the tooth width direction having a relatively small diameter. At this time, at the both ends 11b in the tooth width direction of the tooth profile forming portion 11, the pressure due to the pressing is lower than the center in the tooth width direction, so that it does not act to push and expand the tooth form Rt of the rolling die R, so-called retract. The bottom of the tooth form Rt of the rolling die R is slightly filled. Therefore, as shown in FIG. 7, a tooth profile (crowning tooth profile) Tc to which the crowning C is applied is formed in the tooth profile forming portion 11 by pressing the rolling die R, that is, simultaneously with the formation of the tooth profile T. Crowning C will be given. The rough material having the crowned tooth profile Tc formed thereon is referred to as a third rough material W3. The support wall 10 constituted by the bottom part ja located substantially at the center in the axial direction between the two pilot holes j prevents the third coarse material W3 from being formed in a deformed state by pressing the rolling die R. Can be prevented.

In the above-described embodiment, since the case where the spur gear Gs is manufactured is shown, the rolling die R having the tooth form Rt formed parallel to the center axis CL of the gear to be manufactured is used. However, the present invention is not limited to this embodiment, and when manufacturing a helical gear, the tooth form Rt is formed so as to be inclined with respect to the center axis CL of the helical gear. By using a flat die or a round die with a tooth shape Rt formed in a helical winding shape,
A helical gear having a helical tooth profile provided with the crowning C can also be manufactured (not shown). In this case, it is particularly desirable to use the second rough material W2 provided with the plurality of tooth profile forming portions 11 as shown in FIG. When forming the helical tooth form Th, as shown in FIG. 8, a plurality of tooth forms Rt of the rolling die R simultaneously contact each tooth form forming part 11 of the second rough material W2. When the tooth forming portion 11 makes one rotation around the axis due to relative movement with the rolling die R, the phase of the tooth T formed on the tooth forming portion 11 and the phase of the tooth Rt of the rolling die R match. The pitch must be accurately determined so that In the present invention, as shown in FIG. 8, by pressing the rolling dies R over the plurality of tooth forming portions 11, the number of tooth forms Rt of the rolling dies R simultaneously contacting each tooth forming portion 11 is increased. And the helical tooth form T formed at the tooth form forming portion 11
Since the phase shift between h and the tooth form Rt of the rolling die r can be eliminated, the pitch can be accurately determined. This is true regardless of the manufacture of gears with a uniform tooth thickness and gears with a crowned tooth profile Tc.
This also applies to the case where the helical tooth profile Th is formed and the case where the spa tooth profile is formed. Then, as described below, a plurality of gears G are manufactured by separating the gears G at the grooves 12.

That is, the third rough material W in which the crowning tooth profile Tc is formed at each of the two tooth profile forming portions 11
3 is cut off by a groove 12, as shown in FIG. Each of the separated rough members is referred to as a fourth rough member W4. At the stage of each fourth coarse material W4, the support wall 1
Since the bottom portion ja of the pilot hole j that has formed 0 remains, no through hole J is provided. Therefore, the fourth jaw W4 is subjected to piercing, cutting, or the like, so that the bottom ja is formed.
By this, the forming of the gear G having the penetrated shaft hole J is completed as shown in FIG.

[0024]

According to the first aspect of the present invention, the pressure at the center in the width direction becomes higher than the end in the width direction when the rolling die is pressed against the portion forming the tooth shape of the rough material. With a simple configuration of forming a rough shape, a method of manufacturing a gear capable of forming a crowning tooth profile by only one step of pressing a rolling die against the rough material and moving the rolling die relative to the roughing material can be provided.

According to the second aspect of the present invention, in the first aspect of the present invention, a plurality of portions where the tooth profile is formed are provided through the grooves in the axial direction of the rough shaped material, so that the rolling is performed over each portion. By pressing the forming dies, it is possible to simultaneously contact the plurality of tooth forms of the rolling dies against the rough material, so that the pitch can be accurately determined, and
Since the grooves are located between the respective portions, the flow of the material of the rough material due to the pressing of the rolling dies is not hindered, and further, the coarse shape in which a crowning tooth profile is formed for each of the portions. It is possible to provide a method capable of manufacturing a plurality of gears by a simple process of cutting a material at the groove.

According to the invention of claim 3, according to claim 1,
In the invention described in the item (2), by forming a shaft hole having a wall extending in the radial direction in the crude material, not only the shaft hole of the gear can be easily formed later, but also the rolling die is pressed. Because the wall supports the pressing force when it is pressed, when the hole for inserting the gear shaft is formed in the coarse material, the gear is deformed by the pressing of the rolling die. It is possible to provide a method of manufacturing a gear that can prevent the gear.

According to the fourth aspect of the present invention, a plurality of portions where the tooth profile is formed are provided in the axial direction of the rough material through the groove, and a rolling die is pressed over each of the portions.
Because the multiple tooth forms contact the rough material at the same time,
The pitch can be accurately determined, and furthermore, since the grooves are located between the respective parts, the flow of the material of the rough material due to the pressing of the rolling die is not hindered, and It is possible to provide a method of manufacturing a gear that can form a plurality of gear tooth profiles.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first raw material formed from a raw material according to the present invention.

FIG. 2 is a cross-sectional view of a second rough material in which a plurality of tooth profile forming portions are provided on the first rough material shown in FIG. 1 via grooves.

FIG. 3 is a cross-sectional view of a third coarse material in which tooth shapes are formed at respective tooth shape forming portions of the second coarse material shown in FIG. 2;

FIG. 4 is a diagram showing a fourth coarse material shown in FIG.
It is sectional drawing of a rough shape material.

FIG. 5 is a cross-sectional view of a gear manufactured by forming a shaft hole passing through the fourth rough material shown in FIG. 4;

FIG. 6 is an enlarged cross-sectional view for explaining a state in which a rolling die is pressed against each tooth profile forming portion of the second rough material to form a crowning tooth profile.

FIG. 7 is a partial plan view illustrating a state where a crowning tooth profile is formed according to the present invention.

FIG. 8 shows a state in which a plurality of tooth forms of a rolling die are simultaneously in contact with each tooth profile forming part when a rolling die is pressed against each tooth profile forming part of the second rough material to form a helical tooth profile. It is an expanded sectional view for explanation.

[Explanation of symbols]

 W1 First coarse material W2 Second coarse material W3 Third coarse material W4 Fourth coarse material G Gear T Tooth shape C Crowning J Shaft hole j Preparatory hole 10 Support wall 11 Tooth profile forming part 11a Center in width direction 11b Tooth Width end d Diameter difference R Rolling die Rt Tooth type

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masataka Iwatsubo 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Yuji 1 Toyota Town Toyota City, Aichi Prefecture Toyota Motor Corporation ( 72) Inventor Toshitaka Suzuki 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Kazuo Uno 1 Toyota Town Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Takashi Anma Aichi Prefecture 1 Toyota Town, Toyota City Inside Toyota Motor Corporation

Claims (4)

[Claims] 1. A method of manufacturing a gear for forming a tooth profile by pressing a rolling die against a coarse material to cause relative movement, wherein a rolling die is pressed against a portion of the coarse material that forms a tooth profile. In this case, the crowning tooth profile is formed such that the pressure at the center in the tooth width direction becomes higher than the end portion in the tooth width direction at that time, and a rolling die is pressed against the coarse material to make relative movement. Characteristic method of manufacturing gears. 2. A plurality of portions in which a tooth profile is formed in the axial direction of the coarse material through grooves, and the coarse material in which a crowning tooth profile is formed for each of the portions is cut off by the groove. The method for manufacturing a gear according to claim 1, wherein: 3. The method for manufacturing a gear according to claim 1, wherein a shaft hole having a wall extending in a radial direction is formed in the crude material. 4. A method of manufacturing a gear in which a tooth profile is formed by pressing a rolling die against a coarse material to cause relative movement thereof, wherein the tooth profile is formed through a groove in an axial direction of the rough material. A plurality of parts are provided, and a rolling die is pressed over each part.