JPS581087A - Gear - Google Patents

Abstract

PURPOSE:To obtain an inexpensive product being more durable than a hardened product, by refining hardness of a steel material within a specific range, and performing plating of specific thickness, when obtaining a gear formed by performing hard chrome plating. CONSTITUTION:A steel material refined to 35-50 Shore hardness is formed to a prescribed gear shape by a machine cutting work, and hard chrome plating is performed to the surface of the gear so as to be 0.03-0.15mm. in thickness. In this case, if Shore hardness is <=35, strength is insufficient, and even if a hard chrome layer is formed, a depression including the chrome layer occurs due to gnawing of foreign matter, etc. On the other hand, if Shore hardness exceeds 50, a gear cutting work becomes difficult. Also, as for thickness of plating, in case of working (hob cutting, etc.) by a standard gear cutting tool, if plating is performed as it is, about 0.05mm. is a limit and even if the back-lash is enlarged, when thickness of plating becomes >=0.2mm., the possibility of peeling-off is increased.

Description

[Detailed description of the invention] The present invention relates to a gear with excellent durability.

Many gears are used as power transmission devices.

Conventionally, gear designs are mainly based on calculations of bending strength, and tooth profiles that match the desired transmission force are selected.
Gradually, from the point of view of extending life and improving reliability, it is becoming more and more common to rely on calculation of wear strength. According to this calculation, the hardness of the meshing tooth surface of the gear greatly influences the life. Therefore, heat treatment is performed as a means to increase the strength.

In heat treatment, the gears are heated to a high temperature and then rapidly cooled, which causes distortion in the wheels, and the contact between the tooth surfaces of the gears does not become uniform. (load per unit area) increases, pitching may occur suddenly,
There will be a big problem if ivy occurs and shortens the lifespan by a considerable amount of km. Therefore, as a means of fixing this, the tooth surface is ground after hardening, but this increases machining time and effort.

Hard chrome plating is used as a tooth surface hardening method instead of hardening, but simple plating has a Vi value and a rounding K value of 0.2 to 0, which provides sufficient compressive strength and durability when plated on a material with low surface hardness.
．． It is necessary to form a 3 m long 9 degree plating layer, and if such thick plating is applied, the 1 m gap will be too small and proper engagement will not be possible. Also, if the thickness of the plating layer exceeds 0.2 m, it will easily peel off.

Not only will the plating not be effective, but it will also have an adverse effect on the other gears that mesh with it.

The relationship between the hardness of the wheel material and the hardness of the gear after hard chrome plating was investigated.

If the hardness of the gear after cutting is 35 to 45 or more on the Shore hardness, the strength after hard chrome plating will be significantly improved, and if the thickness of the plating layer is 0.05 as or more, the hardness will be increased by heat treatment. By comparison, it was confirmed that sufficient wear resistance strength could be obtained.

Thus, according to the present invention, a round steel cable material tempered to a shore hardness of 35 to 50 is formed into a desired gear fist shape by machine cutting, and a hard rubber cord is formed into a thickness of 111iiiK0.03 to 0.15mm. A gear made of 1 gold is provided.

In the present invention, the raw steel materials are machine structural steels and hardenability-guaranteed structural steels (H steels) as defined in J Engineering 8. The tempering method itself is already known.

There is no need to mention this.

If the tempering hardness is less than 35 in Shore hardness, the strength is insufficient and To
b. Even if there is a hard chrome plating layer, both the chrome layer may cave in due to foreign matter getting stuck in it. On the other hand, if the Yoer hardness exceeds 50, gear cutting becomes difficult. A preferable tempered hardness is 40-45 Shore hardness.

The thickness of the hard chrome plating layer K is when processed using standard gear cutting tools (such as hobbing).

Backlash is 0.02~0. For example, if it is a gear of module 5, p OJ~
0.20111, if it is plated.

The limit is 0.05 degrees once. Furthermore, even if the backlash is increased, if the plating thickness exceeds 0.281, the possibility of peeling increases as described above.The practical limit of the plating layer thickness is 0.1 mm*degrees. On the other hand, Shimokuma has a significant effect from 0.03- as illustrated by the Tawaraki Example.

Since the hard chromium plating method itself is well known, there is no need to explain it in detail here.

Next, examples of the present invention and comparative examples will be shown.

Each material shown in the following table was processed and processed by the processing means described in each example to produce e*a3o, Mokujiel 5. Tooth width 1, o -1'r
It is formed into the gear of the module and subjected to durability tests from time to time.

The lifespan and manufacturing cost of the conventional product are assumed to be 1, and 1 is omitted in the same table.

The durability test is carried out as follows9.

Gears with the above dimensions are fixed and meshed with each rotating shaft, one shaft is used as an input shaft, the other is used as an output shaft, the output from the motor is applied to the input shaft, and a brake device is applied to the output shaft. . , 1.800 rj), Il, l on the input shaft
Provides rotational force of torque 3004-1118.

A braking force of 25owI-cm is applied to the output shaft, 1N! The surface was filled with abrasive* and lubricating oil was continuously rotated, and the time (number of days) until 0.1 cm of wear occurred at the pitch point was measured.9.

As described above, a steel material tempered to a sear hardness of 35 to 50 K was machine-cut into gears.

By applying hard chrome plating with a thickness of KO003 to 0.15 cm, it is possible to provide a product that is more durable than the conventional hardened K product at a lower cost.

License applicant: Nisshin Steel Co., Ltd.

Claims (1)

[Claims] 1. A round steel material tempered to a shore hardness of 35 to 50 is formed into a desired gear shape by mechanical cutting, and a gear KO is produced.
Gears made of hard chrome plating with a thickness of 003~Oj5M1m. 2. The gear according to claim 11, item 1. The gear according to claim 1 or 2, which is made of steel and is made of round steel and tempered to a hardness of 40-45K. 0.05~0.
6,64 in 100. 4.4 Scope of claims! The gear described in any one of Items 1 to 3, wherein the steel material is ``longitudinal steel copper material for machine structure'' as referred to in J. ” something that is. 5.4 The gear according to item 4 of patent claim 01111. The steel material is Jllll, IIcM, II) ICM,! ]-C
KaG, 114f9. G) ill (Id) something that can be done.