JPS5832823Y2 - Improvement of tooth forming tool - Google Patents

Description

[Detailed description of the invention] This invention provides a tool for pressure forming toothed elements, in particular, a spline tooth profile, etc. around a cylindrical workpiece without removing material from the workpiece while keeping the workpiece at ambient or room temperature.
This invention relates to improvements in tools that create pressure on tooth profiles such as gear tooth profiles and worm tooth profiles.

Traditionally, various tools have been used commercially to pressure form spline tooth profiles, gear tooth profiles, worm tooth profiles, etc. around cylindrical workpieces without removing material from the workpiece while keeping the workpiece at ambient or room temperature. There is.

Examples of conventional tools that have been commercially successful in this field include those disclosed in U.S. Pat. Nos. 2,994,237 and 3,015,243;
No. 995,964.

An object of the present invention is to provide an improved tooth forming tool having the above-mentioned features that improves tooth profile generation and thus improves wear resistance, fatigue resistance, and service life of the tool.

Another object of the present invention is to provide an improved tool for creating pressure on toothed elements that incorporates improved means for increasing tooth profile generation efficiency.

Another object of the present invention is to provide an improved tooth forming tool that improves the flow characteristics of workpiece material during the tooth forming process and improves tooth forming.

Yet another object of the present invention is to provide an improved tool for pressure forming toothed elements that can reduce the cost of creating tooth profiles on workpieces.

The above objects and other objects and advantages of the present invention will become apparent from the following description and drawings.

Referring to the drawings, Figures 1.3, 4.5 and 6 show an embodiment of the present invention.

The illustrated example according to the invention consists of a specific tooth arrangement and combination of rack-shaped tools, generally designated 10, such tools preferably being arranged in substantially identical pairs and having an involute spline tooth profile. , used for pressure forming involute gear teeth, etc., and the surrounding teeth of thin cylindrical workpieces.

A machine for pressure forming workpieces by metal displacement using a pair of rack-shaped tools according to the present invention is disclosed in the above-mentioned U.S. Pat. Explained in detail.

Generally, a workpiece is positioned between a pair of tools 10 according to the present invention, which are reciprocated in opposite directions across the workpiece to form a tooth profile around the workpiece.

The workpiece is preferably supported by means which allow the workpiece to rotate freely about its longitudinal axis when it is intended to be rotated by the tool according to the invention.

These tools 10 are provided with a tooth profile, generally designated 12, on the working surface in contact with the circumference of the workpiece, and in use, these tools are moved longitudinally by any means, while at the same time moving the tools at the same speed in the opposite direction. Moving.

Since each working surface of the tool is stamped or bonded around the circumference of the workpiece, the gap between the working surfaces of the tool is smaller than the diameter of the workpiece.

To form a tooth profile of the desired configuration around the workpiece, the raw material of the workpiece (usually steel) is flowed radially and tangentially close to the surface so that the diameter is smaller than the original outside diameter of the workpiece. A bump is formed with a diameter larger than the original outer diameter of the processed product.

Since the final position of the workpiece must normally be maintained precisely, the above-mentioned material flow must be taken into account in selecting the diameter of the workpiece section to be acted upon by the tool according to the invention.

To consider and illustrate the common but very important shapes rolled by the tool according to the invention, FIG.
A portion of a finished workpiece 14 with an involute tooth profile or spline 16 formed therein is shown in cross section.

Since no metal material is removed from the workpiece during the cold rolling operation, the diameter of the workpiece before rolling is neither the final outer diameter nor the root diameter.

The rolling diameter D1 of the workpiece 14 is such that the lower displacement tooth profile material area 18 around D1 has a larger diameter than the tooth profile material area 2
is chosen to be equal to 0.

The diameter Dl, or substantially this diameter, forms the pitch line of the rack-shaped tool, such as the tool 10.

The pressure angle Φ of the tooth profile 12 at the position of the tool 10 under rolling pressure, which will be specifically described below, is an angle that satisfies the following relational expression.

cos Φ-D/DIX cos Φ' where D is the pitch diameter of the workpiece 14, Dl is the rolling diameter of the workpiece 14, and Φ is the pressure angle at the pitch diameter of the involute tooth profile 16 of the workpiece 14.

The basic circular pitch of the tool and workpiece is the same.

With this configuration, the linear pitch of the tool tooth profile measured by the pitch line corresponds to the circular pitch of the workpiece tooth profile.

The total tooth depth of at least some of the tooth profiles of the tool 10 in contact with the workpiece 14 is preferably determined such that the tool tooth profile completely mates with the workpiece tooth profile.

In use, a pair of tools 10 are spaced apart from each other, with a button located near their rear ends, so that the working surface of these tools has a diameter equal to the root circle diameter of the workpiece 14, which is less than a few tenths of an inch. A gap is provided to obtain elasticity of the member and compression of the oil film by rolling pressure.

Preferably, only one pass of the tool is made without changing direction during the working stroke.

According to the present invention, the selected tool tooth profile is preferably copper,
Plating with silver or gold, or with other materials such as nickel or chromium, improves the rolling efficiency of the tooth profile and reduces the stress on the tool tooth profile that causes wear and fatigue of the metal, thereby making it resistant to fatigue. This improves the durability and the usable life of the tool surface.

In the tool according to the invention, the pitch lines of the tooth profiles 12 of the tool 10 are kept parallel to the theoretical reference line (no taper), but the tooth tips of these profiles are aligned with the front end of each rack of the tool. (See Figure 3).

This causes the tool 10 to gradually bite into the metal of the workpiece 14 and form an involute tooth profile 16 on the workpiece 14.

1.3.4.5 and 6 show a tool 10 according to the invention, the tooth profile of the mating tool being substantially the same.

Reference numeral 22 represents a theoretical reference line indicating "no taper",
Thus, there is no change in the spacing between the working surfaces of the tools as they move relative to each other across the circumference of the workpiece.

The tooth profile of the tool 10 is designated generally by the numeral 12, and in the illustrated example of the present invention, the tooth profile 12 is defined by the vertical reference lines 24, 26 and 28 and the respective trailing and leading ends 30, 32 of the tool. It is divided into two sections.

As shown in FIG.
is parallel to the theoretical reference line 22 from the front end 32 of the tool 10 to the reference line 24 (see FIG. 1).

The tip surface of the tooth profile in the section between the reference line 26 (see FIG. 1) and the front end 32 of the tool 10 is inclined downwardly toward the front end 32 of the tool 10; The pitch line of the tooth profile between the front end 32 and the front end 32 of the tooth profile remains parallel to the theoretical reference line 22.

The tooth profile i2A lying between the reference lines 24 and 26 is of perfect size and engages the tooth profile to be formed on the workpiece in a mating manner to give the tooth profile of the workpiece its final shape.

According to the disclosure of U.S. Pat. No. 3,015,243, reference line 2
The tooth profile 12A between 4 and 26 has a complementary arrangement shape that engages in a pair with the tooth profile formed on the workpiece, and the pressure angle Φ of the tooth profile 12A when receiving a load is as described above. It is an angle that satisfies the relationship: cosΦ-D/D1×cosΦI.

The tooth profile 12A between the reference lines 24 and 26 engages in an auxiliary relationship the final forming portion of the tooth profile of the workpiece.

Further, according to the disclosure of U.S. Pat. No. 3,015,243 and as described above, the pitch line of the tooth profile 12D between the reference line 24 and the rear end 30 of the rack tapers downward from the reference line 22. The tooth profiles 12D between and rear end 30 are substantially full size and preferably have relief on their sides.

This relief eliminates seam lines and other imperfections.

Such seam lines and gaps are likely to form in the tooth profile of the workpiece at the end of the stroke due to the reduction in the total contact area between the tool and the workpiece as the rolling pressure decreases at the end of the stroke.

According to the present invention, the pitch line of all the tool tooth profiles between the reference line 24 and the front end 32 of the tool is set by the diameter D1 of the workpiece in the above method, so that the linear pitch of the tool tooth profile measured by the pitch line is corresponds to the circular pitch of the workpiece tooth profile measured in a circle having the workpiece diameter DI.

The pressure angle Φ under which all tooth profiles between the reference line 24 and the front end of the tool 32 are loaded is CO8Φ=D/DI, as described above.
Xcost' (This is the angle for the D relationship.

The basic circular pitch of the tool and workpiece is the same.

With such a configuration, the linear pitch of the tool tooth profile measured by the pitch line corresponds to the circular pitch of the workpiece tooth profile measured by a circle having the diameter Dl of the workpiece.

The tooth depth of the tooth profile 12A between the reference lines 24 and 26 is determined so that the tooth profile 12A fully joins the workpiece tooth profile.

The tooth tip surface of the tooth profile between the reference line 26 and the front end 32 of the tool 10 tapers downward toward the front end 32 of the rack, but the pitch line of the tooth profile is parallel to the reference line 22 as described above. This taper is obtained by removing the bamboo at the end of the tooth profile, such as by grinding the tooth profile.

The tip of the leading tooth profile proximate the leading end 32 of the rack may be located substantially at the pitch line 34 of the rack, as shown, or, for example, a few tenths of an inch above the pitch line. It's fine.

The tooth profile portion between the reference line 28 and the front end 32 is relatively shallow;
It is relatively wide and has a sharp corner at the front edge, as shown in Figure 3, which is used to grip and rotate the workpiece.

The length of the tooth profile 12C zone between the reference line 28 and the front end 32 is preferably such that approximately one revolution of the workpiece is made in said zone.

Tooth profile 12B in the zone between the reference line 26 and the front end 32
The tooth tip surface of 12C and 12C is the actual tooth profile 1 as shown by the reference line 36.
It has an upward slope towards 2A.

Preferably, the length of the tooth profile 12B zone between reference lines 26 and 28 is such that at least several revolutions of the workpiece are made in the zone containing tooth profile 12B, and tooth profiles 12C and 12B are approximately 100 mm thick of the desired total penetration thickness of the workpiece. Obtained as a percentage.

The length of the tooth profile 12A zone between the reference lines 24 and 26 is preferably such that about one regenerative rotation of the workpiece is performed in the zone, and the tip surface of the tooth profile 12A is arranged in a plane parallel to the reference line 22, The final molded part of the workpiece tooth profile is created by the actual tooth profile 12A.

The body 38 of the tool 10, including all tooth profiles 12, is initially formed from a high grade tool steel, such as M-50, which is nitrided to provide a hardened outer surface and a tough, follicular core or substructure.

Other heat treatment or hardening means may be used if desired.

According to the present invention, and as shown (enlarged) in FIGS. 3 and 6, the tip, side surface, and root surface of only the tooth profile 12B are plated 40, and the thickness of this plating is preferably about 0.
．． 0001 to 0.0003 inches, but tooth profile 1
The tool steel surfaces of 2A, 12C, and 12D are not plated.

The tooth profile 12 is preferably made of copper, silver or gold, although any metal can be used, such as nickel or chromium.
Plate the surface of B.

Further, to plate the surface of the tooth profile 12B, a normal electrolytic plating method is used as much as possible instead of a chemical welding method.

The surface plating on tooth profile 12B fills the ground roughness and solves the boundary lubrication problem inherent in heavy gear loads.

Such a configuration reduces stress on the tool tooth profile due to metal wear and fatigue, eliminates face fracture or corrosion of the tool tooth profile, and further reduces the unit cost of the workpiece formed by the tool 10.

Therefore, according to the present invention, less than about 10% of the desired total penetration thickness of the workpiece is made by the non-plated tooth profile 12C during the first rotation of the workpiece, and the tooth profile 12C grips and holds the workpiece. , without slipping, and then over at least a number of consecutive rotations of the workpiece by the plating tooth profile 12B, which is approximately a factor of 90 or more of the desired total penetration thickness of the workpiece, so that the final configuration of the workpiece tooth profile is achieved. Non-plated tooth profile 12 during one or more continuous rotations of the workpiece
Created by A.

Such a configuration also increases the service life of the tool, improves the flow characteristics of the workpiece material during the tooth forming process, and further improves the quality of the finished workpiece.

If desired, the leading and trailing edges of the tapered teeth 12B and 12C may have variable radii as disclosed in U.S. Pat. may be provided to eliminate the need for undercutting the workpiece.

FIG. 5 is a plan view of the tooth profile 12, showing how these tooth profiles create a spur gear tooth profile on a workpiece.

As shown, the tool tooth profile 12 is perpendicular to the side of the tool, i.e. perpendicular to the direction of tool travel, but if the tool creates helical teeth in the workpiece, the tool tooth profile is perpendicular to the side of the tool, i.e. It may be tilted in the direction of movement.

In the illustrated embodiment of the invention, the body 38 of the tool includes a ledge 42 and a laterally extending opening 44 for attaching the tool to a machine of the type disclosed in U.S. Pat. No. 2,995,964. This makes it easier.

However, other means may be used to attach the tool.

As is clear from the above, the present invention is applicable to the above 12A.
Among the tooth profile sections consisting of -12B and 12C, the major feature is that only the tooth tip, side and root surfaces of the 12B section are plated.

Such partial plating is not done to save plating material, and in fact, it is much more difficult to plate only the tooth profile 12B than to plate the entire tool tooth profile, and the trade-off for material savings is is too much of a burden.

The partial plating according to the present invention brings about the following effects, and that is why the partial plating is carried out despite the complexity of the partial plating.

First, the plating of the tooth profile 12B fills and smooths the ground rough surface of the tooth profile 12B, and has the effect of solving the boundary lubrication problem inherent in heavy gear loads.

This also minimizes the flow of workpiece metal into the valleys of the tool roughness (created during the manufacturing process) when forming the tooth profile on the workpiece with the tooth forming tool, and also minimizes the flow of workpiece metal into the valleys of the tool roughness (created during the manufacturing process). The flow properties of the product material are improved and the quality of the finished product is improved.

For conventional tooth-forming tools that do not undergo plating, contact between the metal of the tool and the metal of the workpiece to be tooth-formed occurs during rolling, resulting in poor rolling efficiency of the tooth profile and wear of the metal due to stress. The disadvantages were that the tool surface had a short service life due to large fatigue and fatigue.

Plating sections of the tooth profile 12B eliminates such deficiencies and minimizes face fracture or corrosion of the tool tooth profile.

The unplated teeth 12C are important for initially gripping and rotating the workpiece without slippage problems.

Plating the entire tool may further increase the advantages mentioned above for 12B plating, but it poses significant difficulties in gripping the workpiece and starting the tooth preparation mold.

The unplated tooth profile 12A is important to avoid undesired relative movement between the tool and the workpiece and to remove the final workpiece without slippage problems.

As mentioned above, less than about 10% of the desired total penetration thickness of the workpiece (desired depth of the tooth profile formed in the workpiece) is achieved by the tooth profile of the non-plated third section 12C during the first revolution of the workpiece. , then about 9 of the desired total penetration thickness of the workpiece.
0 or more plating is performed by the tooth profile of the second section 12B in at least a number of consecutive revolutions of the workpiece, and the final configuration of the workpiece tooth profile is achieved by the non-plating tooth profile in one or more additional successive revolutions of the workpiece. It is created by a tooth profile of one section 12A.

Therefore, by plating only the long second section 12B, the tool of the present invention achieves almost the same plating effect as when plating the entire section, and also has a small non-plated portion 1 at both ends.
By leaving the 2C212A, the initial gripping can be carried out without slippage problems and the final processing can be carried out without undesired relative movement between the tool and the workpiece and without the problem of slippage and the tooth profile of the workpiece. It is a 12A item that will help you complete your creation smoothly.

Although one embodiment of the present invention has been illustrated and described above, various changes and modifications can be made without departing from the spirit of the present invention.

Next, embodiments of the present invention will be listed.

(1) A tool according to the claims, in which the wall thickness of all the tooth profiles buttoned in each section measured along the pitch line is constant from section to section from the tooth profile in the first section to the front end.

(2) A tool according to the claims, in which all tooth profiles have a common pitch line.

(3) In the tool described in the claims, the distance between each tooth profile of the continuous sections measured along the pitch line is constant from the front end to the first section of the tooth profile, and the thickness of the plating on the tooth profile surface buttoned to the second section is A tool having a diameter of approximately 0.0001 to 0.0003 inches.

(4) A tool according to the claims, in which the surface of the second section of the tooth profile is plated with a metal selected from the group consisting of gold, silver, copper, nickel, and chromium.

(5) A tool according to the claims, which includes a fourth section of the tooth profile close to the rear end, and the tip of the tooth profile in the fourth section is sloped toward the rear end.

(6) In the tool described in the claims, the height of the bamboo at the end of the tooth profile in the second and third segments is continuous with the height of the bamboo at the end of the tooth profile toward the first segment. Tools to be reduced to.

(7) Use the tool described in the claims to turn the body into an M-
50 copper, preferably nitride hardened M-50 steel.

[Brief Description of the Drawings] Fig. 1 is a side view of a rack-shaped tool according to the present invention, Fig. 2 is a partial view of a typical involute spline pressure-formed by the tool according to the present invention, and Fig. 3 is a side view of a rack-shaped tool according to the present invention. FIG. 4 is a front view of the left end of the tool shown in FIG. 1, FIG. 5 is a partial plan view of the tool shown in FIG. 1, and FIG. 2 is an enlarged sectional front view showing a portion of one of the tool tooth shapes shown in FIG. 1. FIG. 10...Rack type tool, 12...Tooth profile, 14...
Processed product, 16...Spline, 18.20...Tooth profile material area, 22...Theoretical reference line, 24.26.28.
36... Reference line, 30... Rack rear end, 32...
Front end of rack, 34...Pitch line, 38...Body
42...Protrusion, 44...Opening.

Claims (1)

[Scope of utility model registration request] A tool 10 for pressure forming tooth profiles 16 around a cylindrical workpiece 14 includes a body formed of tool steel and having a leading end 32 and a trailing end 30 and further having a plurality of tooth profiles 12. The first section 12A of the tooth profile is disposed between the front end 32 and the rear end 30, and each of the tooth profiles 12A buttoning the first section corresponds to one of the tooth profiles 16 to be formed into the workpiece 14. The second section 12B and the third section 12C of the tooth profile are arranged 12A-12B- between the first section 12A of the tooth profile and the front end 32. The second section 12B and the third section 12CK are arranged in the order of the tooth profile sections 12C,
! The tip 36 of the tooth profile has a slope that slopes downward toward the front end 32, and the length of the second segment 12B of the tooth profile is longer than the length of the first and third segments 12A and 12C of the tooth profile. A tooth forming type tool which is elongated and is formed by plating the tip, side and root surfaces of only the second section 12B of the tooth profile.