JPS60186334A - Method of forming bearing ball track - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION The present invention relates to a method of forming precision ball tracks in components, particularly outer race members of universal joints.

[Prior art]

A method in which a ball raceway is formed to engage the balls of a bearing; a method in which the ball raceway is molded into the part; a method in which the raceway is formed in a rough-finished workpiece by grinding, machining or cold forming; There are methods such as first cold-opening or forging a roughly sized raceway during the molding process of the part, and then grinding and machining the molding pressure raceway into a precise shape. The last mentioned method is the most common method used when a precise shape of the top groove is required, as it allows the top groove of precise dimensions to be made without wasting much material. Furthermore, this method of forming the upper groove causes less wear on the grinding and machining tools than when grinding ball tracks on a workpiece that does not initially have ball tracks.

Precision ball tracks are required, for example, for bearings with spherically fitted inner and outer race members arranged in meridian grooves for ball retention. In a universal joint of the type engaged by. An example of this type of universal joint was published on July 7, 1936 by Alfred H.
U.S. Patent No. 2, issued to d H.
046, No. 584, and to the same inventor, 4/1928.
No. 1,665,280, issued May 10, 2003. The major features of this type of universal joint are:
It is to have constant speed property or uniform speed property. That is,
The rotational speed of the shaft interconnected with the inner race member is the same as the rotational speed of the shaft interconnected with the outer race member, regardless of the relative angular position between the inner and outer race members within a range of relative angular positions. It is.

This type of universal joint has therefore become commonly used in front wheel drive systems of automobiles.

A typical constant velocity universal joint of the type described above, often referred to as a Lutzetsuba joint, is formed on the spherical outer surface of the inner race member with six meridional precision ball trajectories on the spherical inner surface of the inner race member. The ball is first formed into six child parts, and then machined so that each ball track has the desired precise shape.

During grinding and machining operations, part of the machined surface of the tool will wear out, so in order to maintain the accuracy of machining and grinding operations,
Tools will need to be replaced regularly. Such periodic replacement is uneconomical in terms of the cost of replacing the tool and the loss of working time while changing the tool.

If the ball track is formed in the part in a cold-open forming operation,
The metal of the part is moved considerably, especially in the top region of the ball track. The metal in the top region of the ball track is the most difficult part to form when forming the ball track. Therefore, it is desirable to provide some relief in the top region of the ball track to facilitate the forming process.

When a ball race is ground into a part, the grinding tool is rotated about an axis extending outwardly from the top of the ball race. Therefore, the portion of the grinding tool near the top of the ball track moves relatively slowly and experiences the greatest amount of friction. Friction in the top region of the ball race causes rapid deterioration of the grinding tool, so that it is often necessary to replace the grinding tool and considerable downtime is required. This friction also generates heat, which can cause cracks within the part. Therefore each part must be carefully inspected to detect microscopic cracks. A significant amount of scrap results from inspection for microcracks, increasing manufacturing costs per part. Quality control problems can also arise due to undetected waste.

Therefore, for the production of Rutseppa joints and similar constant velocity universal joints and other machine elements where precision ball tracks are required, the ball track can reduce the amount of grinding, machining tool friction and the amount of scrap produced during manufacturing. A manufacturing method is desired.

[Summary of the invention]

The present invention provides a method for manufacturing a precision ball track for a workpiece, which reduces the friction of the tool used for grinding and machining the ball track compared to conventional methods. The cold-open molding operation becomes easier and the degree of micro-cracking in the workpiece is reduced. The method of the present invention is particularly useful for manufacturing outer race members of constant velocity universal joints, such as Lutzepper joints.

According to the method of the invention, a workpiece is initially formed with a forming relief groove extending within and along a forming die track and a forming pressure track. The ball track is then ground and machined to a predetermined precision shape to produce a precision ball track. Friction of machining and grinding tools is reduced by providing relief grooves to reduce the surface area that can be engaged with tools in areas where machining and grinding is most difficult. Additionally, the relief grooves facilitate metal flow at the top of the ball track during cold forming operations.

It is desirable that the relief groove extends along the soil texture. This is a cold forming device, -! This is the area where the part experiences the greatest amount of resistance to the machining or grinding tool.

In a preferred embodiment, the outer race member of the constant velocity universal joint is formed with a plurality of spaced apart meridian race grooves, each meridian race groove having a meridional groove formed at the top thereof. It has an escape groove. Each meridian race groove is machined and ground to a precise shape, resulting in multiple precision ball trajectories.

The inner race member of a constant velocity universal joint can be manufactured in a similar manner by forming it with a plurality of spaced apart meridian race grooves. Each meridian lace groove is
It has a meridian relief groove formed at its top.

Each meridian race groove is ground to a predetermined precision shape to create a plurality of precision ball tracks.

The primary object of the present invention is to provide a method for forming precision ball trajectories in parts, which method increases the useful life of machining and grinding tools used to create precision ball trajectories; It is an object of the present invention to provide a method whereby the downtime of a manufacturing machine can be reduced and the yield obtained from the manufacturing machine can be increased.

Another object of the present invention is to provide a method of forming inner and outer race members of a universal joint having a series of ball-retaining meridional race grooves in the inner and outer race members.

Still another object of the present invention is to provide precision inner race members and precision outer race members for constant velocity universal joints of the type having a series of ball-retaining meridional race grooves formed in the inner and outer race members. It is to be.

Still another object of the present invention is to form a precision ball trajectory on a component;
It is an object of the present invention to provide a method that facilitates the formation of precision ball trajectories through a cold-open forming operation.

These and many other objects of the invention.

Features and advantages will become apparent to those skilled in the art from the following detailed description and description of the accompanying drawings.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawings, and in particular to FIGS. 1 and 2, a Ruthember-type constant velocity universal joint 10 is shown.

Constant velocity universal joint 10 is well known in the art and will not be illustrated or described in detail herein.

Constant velocity universal joint 10 has an outer race member 12 having an integral shaft 14 extending in a first direction. A spherical cavity 16 is formed in the outer race member 12. The spherical cavity 16 is open in a second direction opposite to the first direction.

As shown in FIGS. 1 and 2, a first track 1B is formed in the outer race member for a series of bearing pressures 20. As shown in FIGS. The first track 18 forms a series of meridian race grooves for ball engagement and has a Gothic arch shape.

The inner race member 22 is connected to the spherical cavity 16 of the outer race member 12.
formed within. Inner race member 22 is mounted to shaft 24 via splines 26 . Inner race member 2
2 has an outer spherical surface 28 with a diameter considerably smaller than the diameter of the spherical cavity 16 of the outer race member 12.

A second track 30 is formed within the outer spherical surface 28 of the inner race member 22, as shown in FIGS. 1 and 2. The second track 30 defines a series of meridian ball-retaining grooves in the form of a gothic arch that engages the bearing pressure 20 .

each of the first orbits is aligned with one of the second orbits;
One of the bearing pressures is captured therebetween in a known manner to permit angular movement of the shaft 24 interconnected with the inner race member 22 relative to the integral shaft 14 of the outer race member. Bearing pressure 20 transmits rotational torque between integral shaft 14 and shaft 24 in a known manner. If desired, the spherical retaining piece 42 can be attached to the outer spherical surface 2B of the inner race member 22 and the spherical cavity 16 of the outer race member 12.
The bearing pressure 20 may be captured in a known manner.

By the way, according to the conventional method, the inner race member 22 and the outer race member 12 are formed by a casting or forging process, and the first raceway 18 and the second raceway 30 are formed by grinding or processing tools thereon, respectively. It is formed by continuous grinding and machining operations. This grinding and machining operation creates a significant amount of friction on the grinding or machining tool, requiring frequent replacement of the grinding tool. Therefore, the operation of the manufacturing machinery used to make the inner and outer race members requires significant downtime and yields are poor.

However, in accordance with the present invention, the inner race member 22 and outer race member 12 can reduce the amount of friction on the processing tool, thereby increasing yields and reducing manufacturing machine downtime.

As shown in FIGS. 1, 2, and 3,
The track 18 of the container 1 has a small groove 32 running along its length.
It is equipped with Similarly, as shown in FIGS. 1 and 2, the track 30 of the container 2 is provided with a groove 34 formed therealong. The small grooves 32, 34 serve as relief grooves, and the first and second raceways 18, 30 are ground into a predetermined precise shape.

Grinding reduces the amount of friction on the machining tools used for machining.

That is, as shown in FIG. 3 for a given first track, the groove 32 is preferably formed at the top of the associated first track. This is because the maximum grinding and machining resistance force occurs at the top of the raceway.

In this way, the grinding and processing tools used for finishing on the predetermined first rough raceway 18a have considerably less friction than when the small grooves 32 are not provided.

It is desirable that the small groove 32 has a width W considerably larger than the depth d for a predetermined first rough track 18a.
Thereby, the friction of the grinding and machining tools used can be significantly reduced without substantially weakening the outer race member 12. For example, the width W of the small groove 32 may be 2 to 4 times the depth d. Further, the small groove 32 is formed on a predetermined first rough track 18.
There is a width in a part of the periphery of a, and the angle θ of the arc is determined. The predetermined angle θ is selected to minimize friction on the grinding and machining tools, yet provide sufficient surface for contact between the predetermined first raceway and the bearing balls disposed thereon. In the illustrated example, the predetermined angle θ is approximately 20, but 10 to 3
It may be an angle of 0.

According to the method of the invention, the outer race member 12 is first formed by casting or forging and has a predetermined first rough raceway 18a formed therein with a formed surface 36 having a forming radius r. ing. The next grinding and machining are performed on the predetermined first rough orbit 1.
8a to produce a polished surface within a predetermined tolerance between the smallest polished surface 38 with the smallest polished radius r2 and the largest polished surface 40 with the largest polished radius r8.

The depth d of the small groove 32 is the maximum polishing radius r8 and the forming radius r0.
Since the difference is selected to be larger than the difference between the two, the grinding and processing tools will not hit the bottom 44 of the small groove 32.

The remaining first and second tracks 18.30 of the inner and outer race members 22.12 are each formed in a manner similar to the method for forming the predetermined first tracks described above.

It should be noted that the method of the present invention is more preferably applied to the outer race member 12 than to the inner race member 22. The first raceway 18 for the outer race member 12 is designed to be counterbalanced to the bearing ball 20 such that the ball 20 normally engages the raceway surface not including the top of the raceway. This is done to maximize the bearing area between the bearing balls 20 and the outer race member 12. therefore.

Even if a part of the first track 18 is removed by providing a small groove 32,
It only removes the part of the first track that does not carry any load. Therefore, when the method of the present invention is used to fabricate the outer race member 12 of the constant velocity universal joint 10, the formed surface 36 of the first raceway 18a provides maximum resistance to machining and grinding tools.
The useful life of the grinding and machining tool used can be increased by removing this portion without affecting the function of engagement of the I1II ball 20 and its associated first track.

In contrast, the second track of the inner race member 22 is generally designed in such a manner as to provide substantial surface contact near its top. Therefore, the inner race member 22
When made as described above according to the method of the present invention, the areas of maximum contact between the bearing ball 20 and its associated second raceway 300 will be on either side of the minor groove 34.

Therefore, in some applications, only the outer race member 12 may be formed according to the method of the present invention, and the inner race member 22 may be formed by conventional methods. It's a trench, inner race member 22
The small groove 34 formed in the track 30 of the container 2 may be formed at a location other than the top of the second track. For example, although not shown, two small grooves may be formed on both sides of the top of the track of the container 2 and spaced apart from the top by a predetermined distance and angle.

It may also be provided on the second track.

What has been described above is the best mode contemplated by the inventors at the time of filing of this application for carrying out the invention. The above description is merely illustrative of the present invention, and various modifications and variations will occur to those skilled in the art based on the above description and the accompanying drawings without departing from the spirit of the invention. For example 1
The grinding and processing steps according to the present invention can be carried out using a single-hole type or punch-hole type with a grinding wheel. Such modifications are naturally included within the scope of the claims.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a constant velocity universal joint made by the method of the present invention. FIG. 2 is a sectional view taken along line 2-2 in FIG. 1. 3 is an enlarged partial cross-sectional view of the universal joint of FIGS. 1 and 2, and is for explaining the relief groove in detail. DESCRIPTION OF SYMBOLS 10... Constant velocity universal joint, 12... Outer race member, 22... Inner race member, 18... First track, 30... Second track, 20... ...Bearing pressure, 32
．． 34...Small groove (becomes an escape groove). Patent Applicant GKN Automotive Components Incorporated Agent Kazuka Yamakawa ((
・B) 2 people)

Claims (1)

[Scope of Claims] (1) A method for forming a precision bearing ball raceway in a component, comprising: forming a molded upper raceway and a clearance groove extending along the ball raceway in the component; and forming the molded upper raceway into a predetermined shape. A bearing ball track Mikisaka method comprising: a grinding step of producing the precision ball track by grinding it into a precise shape. (2. The method according to claim 1, wherein the component includes an inner race member of a universal joint, the inner race member includes a plurality of meridian tracks for ball engagement, and the precision ball track includes at least one of the plurality of ball-engaging meridian tracks. (3) The method according to claim 1, wherein the component is an outer race member of a universal joint. , wherein the outer race member includes a plurality of ball-engaging meridional tracks, and the precision ball track includes at least one of the plurality of ball-engaging meridian tracks. (4) ) The method according to claim 1, characterized in that the escape groove extends along the top of the formed upper track. (5) The method according to claim 1, The method according to claim 1, wherein the relief groove has a width substantially larger than a depth with respect to the molded track. A method according to claim 1, characterized in that the relief groove has a predetermined depth substantially greater than the depth of grinding during the grinding step. A method characterized in that the relief groove extends around the periphery in an arc of 10 to 20 with respect to the molded track. (8) An inner race member, an outer race member, and a series of ball retaining meridians in these races. 1. A method of forming an outer race member of a universal joint having a shaped race track, the method comprising: a cavity formed therein and a plurality of spaced apart meridional race tracks formed within the cavity, each race track having a cavity formed therein; a step of forming an outer race having a meridian relief groove formed at its top; a grinding step of grinding each of the spaced meridian tracks into a predetermined shape to form a plurality of precision ball tracks; (9) In the method according to claim 8, each of the meridional relief grooves is formed in the plurality of grooves associated therewith. 9. The method of claim 8, wherein each of the spaced meridional race tracks has a width dimension that is substantially greater than a depth dimension. The method of claim 8, wherein each meridional relief groove has a predetermined depth dimension that is substantially greater than the depth of grinding during the grinding step. A method,
Each said meridian relief groove has a diameter of 10 to 10 for each of said plurality of spaced apart meridian race tracks associated therewith.
A method characterized in that it extends around the periphery in an arc of 30 degrees. (12) A method of forming an inner race member of a universal joint having an outer race member, an inner race member, and a series of ball-engaging meridional race trajectories within these members, the inner race member comprising: an outer spherical surface; forming an inner race member having a plurality of spaced apart meridional race tracks, each meridional race track having a meridional relief groove formed at the top thereof; A method for shaping a bearing ball raceway, comprising a continuous process including a grinding process for forming a plurality of precision ball races by grinding the raceway into a predetermined precision shape. (13) The method according to claim 12,
The method characterized in that each said meridional relief groove has a width dimension that is substantially greater than a depth dimension for each of said meridional race tracks associated therewith. (14) The method according to claim 12,
The method characterized in that each meridional relief groove has a predetermined depth that is substantially greater than a grinding depth dimension during the grinding step. (15) 4? 13. The method of claim 12, wherein the meridional relief groove has a diameter of 10 to 10 for each of the plurality of spaced meridian race tracks associated therewith.
A method characterized in that it extends around the periphery in an arc of 300 degrees.