JPH07301285A - Orthogonal shaft speed reduction gear - Google Patents

Abstract

PURPOSE:To reduce an amount of abrasion loss in a work wheel as well as to improve its service life so sharply by setting the material of this work wheel for an orthogonal shaft speed reduction gear to brass added wided with silicon and manganese, using specified mineral oil for lubricating grease as additives, and applying an ureal thickening agent for the end. CONSTITUTION:Material for a worm wheel 2 is brass added with silicon and manganese, separating particles out of an intermetallic compound of silicon- manganese being very high in hardness in structure, and it is resistible to frictional contact in its partial structure owing to this intermetallic compound. Despite this fact, its surface hardness is average of other copper alloys as in HV180, having slidability and conformability. Lubricating grease 3 is composed of a ureal thickening agent in addition to mineral oil, and as to additives, dialkyldithiol carbamic acid molybdeum (MoDTC) and dialkyldithionic acid molybdenum (MoDTP) are added, whereby molybdenum disulfide is formed on a lubricating surface, through which wear resistance is improved. In this connection, grease consistency should be set to a range of 380 to 410.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small orthogonal shaft reducer used in combination with a small motor as a power source for industrial conveyors (belt conveyors, etc.) and processing machines.

[0002]

2. Description of the Related Art In recent years, there has been an increasing need for a right-angle reducer that can be used in combination with various motors as a power source for industrial conveyors such as belt conveyors. The reason is that the maximum dimension of the motor and reducer when combined is the axial direction of the motor, so if there is a limit to the dimension in the direction of the drive shaft, the motor and output shaft can be placed at right angles to reduce the speed of an orthogonal shaft. This is because a machine is required. Particularly in recent years, in order to reduce the size and weight of the belt conveyor and reduce the width of the belt, it is possible to reduce the dimensions including the motor while arranging the conveyor shaft and the output shaft of the speed reducer in parallel. Is needed.

Conventionally, worm gears have often been used in orthogonal axis reduction gears. In recent years, there has been a demand for downsizing and longer life of the equipment as described above, and there is a need for a worm gear that is smaller and has higher load bearing performance than the conventional one, which meets this requirement. As for lubrication, the grease bath lubrication system is adopted because the seal structure can be configured relatively easily and the mounting direction is free and maintenance is simple.

An example of a conventional orthogonal axis speed reducer will be described below. FIG. 1 shows a cross-sectional view of a conventional orthogonal axis speed reducer. FIG. 1A is a front view, and FIG. 1B is a side view. In FIGS. 1A and 1B, 1
Is a worm pinion, 2 is a worm wheel meshed with the worm pinion, 3 is lubricating grease for the worm gear, 4 is a gear case, and 5 is a parallel gear power-coupled to a motor. The gear case has a mounting area of 90 mm square for mounting the flange to realize the miniaturization of the equipment, and the worm gear module is a right-angled module 1.25 to 1.6 to accommodate the gear in this size.
The reduction ratio in the worm gear part is 1:10 to 1:20.

Worm gears are more liable to wear due to large slippage on their tooth surfaces, as compared with involute spur gears and helical gears generally used as gear reducers. Therefore, in order to improve the wear performance, the above-mentioned 1 worm pinion has a high tooth surface hardness, and is hardened in steel and tooth-polished for the purpose of improving the tooth surface roughness. The worm wheel 2 that meshes with the worm pinion 1 is generally made of a copper alloy such as phosphor bronze, aluminum bronze, or brass, which has a lower hardness than the worm pinion 1 and has good slipperiness and conformability. Also, as mentioned above, oil or grease is used to lubricate the tooth surface to improve wear resistance, but in the case of a small orthogonal shaft reducer, lubrication is done with grease because of the simplified seal structure and ease of installation and maintenance. . As the lubricating grease 3, mineral oil or synthetic oil is used as a base oil, and a urea-based thickening agent is used, and zinc dialkyldithiophosphate (hereinafter referred to as ZnDTP) is used as an additive.

The power of the motor is transmitted to the worm gear through the parallel gear 4, and the power is output from the output shaft 6 into which the worm wheel is press fitted.

[0007]

However, in the above-mentioned orthogonal shaft reducer, when a high torque of about 200 kg · cm is applied to the output shaft, the tooth right angle module 1.25 to 1.6 described in the above-mentioned prior art. With a small worm gear, the contact pressure between the worm pinion and the worm wheel is large, and the sliding speed is high, so the worm wheel, which has a lower hardness than the worm pinion, wears out early. In addition, for lubrication, extreme pressure agents and antiwear agents added to the lubricant are important in order to withstand the surface pressure, but with conventional lubricating grease, the lubrication effect is low and it is not possible to suppress wear of the worm wheel and the orthogonal axis The speed reducer had a short life.

[0008]

In order to solve the above problems, in the orthogonal shaft reduction gear of the present invention, the gear of the orthogonal portion is composed of a worm pinion and a worm wheel, and the material of the worm wheel is silicon and manganese. With the added brass, the lubricating grease of the worm gear part is molybdenum dialkyldithiocarbamate (hereinafter MoD) as an additive.
TC) and molybdenum dialkyldithiophosphate (hereinafter referred to as MoDTP) as a base oil, and a urea-based thickener is used as a grease.

[0009]

With the above structure, since the output torque of the small reduction gear is a high torque of about 200 kg · cm, the wheel material has good conformability and wear resistance even if excessive surface pressure is applied to the worm gear. Therefore, it is less likely to wear, and the effect of the additive of lubricating grease can significantly reduce the wear of the wheel and extend the life of the gear.

[0010]

EXAMPLE FIG. 1 shows the structure of a speed reducer. Although the configuration is the same as the conventional orthogonal axis reducer described in the above-mentioned prior art,
The material of the worm wheel 2 and the lubricating grease 3 are different.

The material of the worm wheel 2 is to add silicon and manganese to brass to deposit particles of a silicon-manganese intermetallic compound having a very high hardness in the structure, and this intermetallic compound causes frictional contact in a part of the structure. Endure. However, the surface hardness is similar to HV180 and other copper alloys, and has slipperiness and conformability. If the wheel is harder than this, seizure will occur on the friction surface, significantly reducing the life of the gear.

The lubricating grease 3 is composed of a urea-based thickening agent in mineral oil, and by adding MoDTC and MoDTP as additives, molybdenum disulfide is formed on the lubricated surface to improve wear resistance. The grease consistency is 380-41.
It is set to 0. If the consistency is softer than this, it tends to leak to the outside, and if harder than this, the fluidity deteriorates, making it difficult to maintain the lubricating performance for a long time.

[0013]

[Table 1]

Table 1 shows the results of a comparative experiment on the wear amount of the worm wheel of this embodiment and the conventional comparative example.

[0015]

[Table 2]

Table 2 shows three conventional comparative examples of wheel materials.

[0017]

[Table 3]

Table 3 shows two conventional comparative examples of lubricating grease. In Experiment 1, the retention method of the Timken test conforming to ASTM was used to confirm the lubricating performance. However, the block is made of a worm wheel material according to the worm gear conditions, the test load and the test rotation speed are matched to the actual machine conditions, and the test load is 21 lbs and the test rotation speed is 300.
r. p. m. A thermocouple was attached to the block to measure the block temperature. The amount of wear was determined by the difference in block weight before the test and after the test.

Experiment 2 is a life test of an actual machine using an actual orthogonal axis speed reducer having the same structure as that of the embodiment. The motor output is 90W, the total reduction ratio of the reducer is 1:75, the worm wheel tooth right angle module is 1.6, the reduction ratio of the worm gear is 1:10, and the load torque applied to the output shaft is 200kg.
cm, test time was 300 h, and the amount of wear was calculated by measuring the shape of the wheel before and after the test.

From Table 1, it was confirmed that the wheel material, brass added with silicon and manganese of the example of the present invention, has less wear amount of the wheel in both life test result and chimken test result than other comparative examples. it can. The surface hardness is lower than that of the conventional aluminum bronze of Comparative Example 2, and the amount of wear is small though it is not much different from other Comparative Examples. It is possible to confirm the effect of improving the wear resistance performance by forming an intermetallic compound having high hardness.

As the lubricating grease, the urea-based grease using MoDTC and MoDTP as the additives of the embodiment of the present invention has the smallest amount of wheel wear in both the life test result and the Timken test result. Further, in other surface conditions, seizure, galling, and blackening were observed in the other comparative examples, and the sample block temperature in the Timken test was also high, confirming the superior load-bearing performance due to the difference in additives. Therefore, it can be confirmed that the combination of the wheel material and the lubricating grease of this example is significantly effective in the life of the gear, as compared with the other comparative examples.

Although it is clear from Table 1 that the wheel material and the lubricating grease of the examples of the present invention are effective in improving the life of the gears as compared with other conventional comparative examples, even if they are used individually. Considering the test time and the amount of wear of the wheel, it is estimated that the wear amount reaches 1 mm or more at 5000 h or more under a high load of output torque of about 200 kgcm, and the worm wheel of module 1.6 is used. It is presumed that it is difficult to obtain a long life of 5000 hours or more because the tooth thickness is less than 1.5 mm. The combination of the wheel material and the lubricating grease of the embodiment of the present invention makes it possible to obtain a long service life of 5000 h under a high load of output torque 200 kg · cm in an orthogonal shaft reduction gear using a small worm gear. Can be confirmed.

[0023]

As described above, according to the present invention, the worm wheel of the orthogonal shaft reducer is made of brass containing silicon and manganese, and the lubricating grease is urea-based grease containing MoDTC and MoDTP as additives. The wheel improves the wear resistance while maintaining the slipperiness and conformability as a copper alloy, and the additive of lubricating grease improves the lubricity of the friction surface, suppressing the temperature rise of the friction surface even under high load. Therefore, it is possible to significantly reduce the wear amount of the worm wheel and significantly improve the life of the orthogonal shaft reducer.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a conventional and present invention orthogonal shaft reduction gears.

[Explanation of symbols]

 1 Worm pinion 2 Worm wheel 3 Lubricating grease 4 Gear case 5 Parallel gear 6 Output shaft

Claims (1)

[Claims] 1. An orthogonal shaft reducer in which an input shaft and an output shaft are orthogonal to each other, and the orthogonal gear is composed of a worm pinion and a worm wheel meshing with the worm pinion, and the worm wheel is made of silicon and manganese. It is brass added, and the lubricating grease of the worm gear part uses mineral oil or synthetic oil containing molybdenum dialkyldithiocarbamate (MoDTC) and molybdenum dialkyldithiophosphate (MoDTP) as a base oil, and a urea thickener is used. Orthogonal shaft speed reducer characterized by the above grease.