JP2002139055A - Tapered roller bearing and its preload setting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tapered roller bearing and its preload setting method whereby the preload can be accurately set and managed quickly using a rotational torque value. SOLUTION: The tapered roller bearing includes conical rollers 3 such that the surface roughness Ra of the major end face 3a of each roller 3 is below 0.1 μm and the surface roughness Ra of a large flange surface 1a of the inner ring 1 in slide contact with the major end face 3a is below 0.2 μm, whereto a rust preventive oil having a dynamic viscosity of 20-50 mm2/s at 25 deg.C is attached, and the preload is set by the rotational torque. This allows stabilization of the bearing width through a short period of run-in rotation and giving accurate measurements of rotational torque stably even in the low speed rotating condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tapered roller bearing which uses a rust preventive oil to enhance rust resistance and is applied with a preload, and a preload setting method for assembling the same.

[0002]

2. Description of the Related Art As shown in FIG. 2, a tapered roller bearing is designed such that the vertices of an inner ring 1, an outer ring 2 and a tapered roller 3 are concentrated at one point on the center axis of the bearing, and the radial load and the radial load are reduced. The bearing is particularly suitable for applying an axial load and a combined load thereof, and has a large load capacity.

Such a tapered roller bearing is applied to a bearing for supporting a pinion shaft of a differential gear of a truck or other automobile, or an industrial machine such as a hydraulic pump or a hydraulic motor. (Including the time required for transportation)
It is stored in a state where rust-preventive oil containing rust-preventive additives is adhered to important points.

[0004] Usually, a rust inhibitor has a polar group and a lipophilic group in one molecule, and is strongly adsorbed to metal and has good solubility in oil.

[0005] The rust-preventive oil containing the rust-preventive additive forms a dense oil film on the metal surface in cooperation with the rust-preventive additive and oil molecules. Has the effect of protecting.

In order to increase the rigidity of the above-mentioned tapered roller bearing or to eliminate the gap in the bearing and to improve the rotational accuracy, when the bearing is incorporated in the above-mentioned application, a load (preload) is applied to the roller (rolling element). ) Is loaded. As shown by arrows in FIG. 2, the preload is shifted by a predetermined width so that the inner ring 1 and the outer ring 2 pass each other along the axial direction (in a direction opposite to each other), and the outer ring 2 and the inner ring 1 Is applied by contact at an appropriate pressure. In order to apply an appropriate preload to the bearing in this way, it is necessary to measure the rotational torque of the bearing and determine an appropriate preload.

In order to determine whether or not an appropriate preload is applied to the tapered roller bearing, the rotation torque is measured by rotating the tapered roller bearing at a low speed (usually 100 rpm or less) due to the assembly process. Like that.

In order to accurately measure the rotational torque of the bearing in this manner, the large end face 3a at one end of the frusto-conical roller 3 is required.
However, it is necessary to perform the running-in operation sufficiently until the inner ring 1 comes into contact with the large flange surface 1a (that is, the state in which the bearing width dimension is stabilized).

Incidentally, the rotation speed of the bearing is 20 to
At a low speed of about 100 rpm, most of the cause of the rotational torque of the tapered roller bearing is sliding friction between the large end surface 3a of the roller and the large flange surface 1a of the inner ring, and the roller 3, the inner ring 1 and the outer ring 2 The effect of torque due to rolling friction and the like that occurs during is very small.

[0010]

However, when the bearing is rotated at a low speed and its rotational torque is measured in order to determine whether or not an appropriate preload is applied, the rotational torque value must be reduced. In many cases, the range between the maximum value and the minimum value was not stable, and it was not easy to reliably obtain an accurate measurement value.

Further, in order to accurately measure the rotational torque of the tapered roller bearing, it is necessary to sufficiently rotate the tapered roller into the bearing so that the roller large end surface and the inner ring large flange surface are in contact with each other (ie, when the bearing width dimension is smaller). Although it is necessary to make the bearing stable and stable, it is necessary to rotate the bearing sufficiently for a long time until such a steady state is reached. Work efficiency of assembly and preload setting could not be improved.

Further, depending on various uses of the tapered roller bearing, there are a case where a relatively small amount of rust preventive oil is applied and a case where a relatively large amount of rust preventive oil is applied.

Specifically, as the former example, a tapered roller bearing used for a wheel of an automobile has a lubricating oil that leaks out when the grease is filled in by an automobile manufacturer, or is mixed with the antirust oil and lubricated. Since the service life may be shorter than originally expected, a relatively small amount of the rust preventive oil is adhered by diluting the rust preventive oil with a solvent or the like.

On the other hand, for tapered roller bearings used to support the pinion shaft of a differential gear, the preload is often set by controlling the torque with the rust-preventive oil as shipped from the bearing maker. A small amount of rust preventive oil (for example, lubricating oil type) is used, and more rust preventive oil than required for rust prevention is applied to prevent torque fluctuation due to oil shortage at the time of preload setting.

As described above, in the tapered roller bearing, it is necessary to change the type and application amount of the rust-preventive oil according to the application, which requires a large number of man-hours and increases the cost of producing the bearing.

An object of the present invention is to solve the above-mentioned various problems and to provide a tapered roller bearing in which a preload can be accurately and easily set by a rotation torque value.

In addition, when the bearing is incorporated, the rotating torque value is stable even at low speed rotation, and the bearing width dimension is stabilized by short running-in rotation, so that the preload of the tapered roller bearing using rust preventive oil can be reduced for a short time. It is a method that can be set with.

Another object of the present invention is to provide a tapered roller bearing in which the type and amount of rust preventive oil need not be changed according to the use of the tapered roller bearing, and the number of man-hours to be controlled is reduced as much as possible to suppress the cost of manufacturing the bearing.

[0019]

In order to solve the above-mentioned problems, according to the present invention, a tapered roller arranged between a raceway surface of an outer ring and a raceway surface of an inner ring, and the tapered roller is rotatably held. A tapered roller bearing in which a large end face of the tapered roller is guided by a flange provided on the inner ring in a state where a preload is applied, wherein a kinematic viscosity at 25 ° C. within the tapered roller bearing is 20 to 50 mm. A rust-proof tapered roller bearing characterized by the attachment of ² / s rust-proof oil was used.

In the tapered roller bearing of the present invention configured as described above, since the rust-preventive oil is adjusted to a predetermined kinematic viscosity, it is stable even when rotated at a low speed (usually 100 rpm or less). An accurate measured value of the rotational torque can be obtained, and the bearing width dimension is stabilized by the familiar rotation for a short time.

Also, the surface roughness Ra of the large end face of the conical roller is
The tapered roller bearing is 0.1 μm or less, and the surface roughness Ra of the large flange surface of the inner ring slidingly contacting the large end surface is 0.2 μm or less. It is excellent in the stability of the number and the rotational torque, and the effect of the kinetic viscosity of the attached rust-preventive oil is sufficiently exhibited to provide a high-performance tapered roller bearing.

As a rust-preventive oil having a predetermined kinematic viscosity change rate, when the oil is kept in a bearing at 60 to 70 ° C. for 8 hours and then cooled for 1 hour, the kinematic viscosity reduction rate is 20%. The above-mentioned tapered roller bearing in the case of rust-preventive oil can accurately set and control the preload according to the rotational torque value, and measure the rotational torque accurately and stably even when rotated at a low speed (usually 100 rpm or less). Is obtained.

Any of the tapered roller bearings described above can be applied as a tapered roller bearing for supporting a pinion shaft of an automobile differential gear.

In any of the above-described tapered roller bearings, in order to eliminate the need to change the type and application amount of the rust-preventive oil in accordance with the use of the tapered roller bearing, the amount of the rust-preventive oil to be applied should be set to 0. 8 to 1.1 mg / cm ² .

When a predetermined amount of the rust-preventive oil having a small change with time in kinematic viscosity is applied, it is possible to prevent the grease mixed with the rust-preventive oil from flowing out. It can prevent a short life,
Further, the stability of the torque can be ensured. Such an effect can be more reliably obtained by setting the surface roughness of the large end surface of the conical roller and the surface roughness of the large jaw surface of the bearing inner ring to a predetermined value or less.

In order to solve the problem that the efficiency of the assembling and adjusting work of the bearing is low as described above, according to the present invention, the surface roughness Ra of the large end face of the conical roller is set to 0.1.
When assembling a tapered roller bearing of 1 μm or less and having a surface roughness Ra of a large flange surface of an inner ring slidingly contacting the large end surface of 0.2 μm or less, a preload is adjusted while measuring a rotational torque of the bearing. In the setting method, the bearing is set to 2
The preload setting method for the tapered roller bearing is characterized by lubricating with a rust preventive oil having a kinematic viscosity at 5 ° C. of 20 to 50 mm ² / s.

When a bearing is lubricated with a rust-preventive oil having a predetermined kinematic viscosity,
A tapered roller bearing that can accurately set and manage the preload based on the rotational torque value because stable and accurate rotational torque measurement values can be obtained even when rotated at low speeds and the bearing width dimension is stabilized by short run-in rotation. Preload setting method.

[0028]

BEST MODE FOR CARRYING OUT THE INVENTION The rust preventive oil used in the present invention is 25%.
A rust-preventive oil having a kinematic viscosity at 20 ° C. of 20 to 50 mm ² / s,
It is a composition in which a rust inhibitor is blended with the lubricating oil, and the type is not particularly limited. The general classification of rust preventive oils includes solvent-diluted rust preventive oil, petrolatum type rust preventive oil, lubricating oil type rust preventive oil, and any of them can be used.

The rust inhibitor has a polar group such as a carboxylate, a sulfonate, an ester, an amine, an amide, and a phosphate and a lipophilic group in one molecule, and strongly adsorbs to a metal. Although it is a compound showing good solubility in oil, for example, an alkyl succinic acid derivative having an alkyl group such as C _{12 to} C ₁₈ is often used, and its addition amount is about 0.05%. Other typical examples of the rust inhibitor include, as metal soaps, calcium, zinc or lead salts of lanolin fatty acids, wax oxides or their metal soaps, or naphthenic acid soaps, and as esters, sorbitan monooleate , Pentaerythritol monooleate and the like, and sulfonates and phosphites. Examples of the amine include rosin amine and N-oleyl sarcosine.

The rust preventive oil has a kinematic viscosity at 25 ° C. of 20 to 50 m.
The type of lubricating oil is selected and adopted so as to be m ² / s. 2
When the kinematic viscosity at 5 ° C. exceeds 50 mm ² / s, when the rotating torque is measured by rotating the tapered roller bearing at a low speed, the rotating torque value fluctuates due to slight rotation fluctuation and temperature change.
It is not preferable because the range between the maximum value and the minimum value is not stable.
On the other hand, if the kinematic viscosity at 25 ° C. is less than 20 mm ² / s, the bearing width dimension is not stable with short running-in rotation, which is not preferable.

When the rust-preventive oil is kept in a bearing at 60 to 70 ° C. for 8 hours and then left to cool for 1 hour, the kinematic viscosity is stable with time so that the kinematic viscosity reduction rate becomes 20% or less. It is preferable to use a rust-preventive oil in order to ensure high performance over a long period of time, especially when exporting.

In the tapered roller bearing according to the present invention, the amount of the rust-preventive oil is reduced to 0.1 in order to eliminate the need to change the type and amount of the rust-preventive oil according to the use of the tapered roller bearing.
8 to 1.1 mg / cm ² . The reason for limiting to such a numerical range is that if the amount of rust-preventive oil deposited is less than the above-mentioned predetermined amount, the rotational torque of the bearing at the time of preload setting cannot be quickly stabilized, and the rotation at the time of preload setting after long-term storage is not possible. This is because the fluctuation of the torque becomes particularly large.If the amount of the rust-preventive oil is larger than the above-mentioned predetermined amount, the grease mixed with the rust-preventive oil is likely to flow out. This is because the life is shortened.

The amount of rust-preventive oil adhered in the present invention is represented by the following formula.
That is, the amount of rust preventive oil attached = (total weight of rust preventive oil adhering to the bearing)
/ (Total surface area of bearing) [However, in the above formula, (total surface area of bearing) = (surface area of inner ring) + (surface area of outer ring) + (surface area of all rollers) + (surface area of cage). ]

The structure of the tapered roller bearing according to the present invention is as follows.
There is no particular limitation, and either a single-row or double-row tapered roller bearing may be used. In the tapered roller bearing shown in FIG. 2, the inner ring 1 and the outer ring 2 in which the roller 3 and the inner ring 1 are integrated as a subunit via the retainer 4 are moved in the direction of the arrow in the drawing so that their axes coincide. It is assembled with preload applied. In such a tapered roller bearing, the roller 3 is guided with its large end surface 3a pressed against the large collar surface 1a of the inner ring 1.

The surface roughness Ra of the large end surface 3a of such a conical roller 3 is 0.1 μm or less, and the surface roughness Ra of the large collar surface 1a of the inner ring 1 is 0.2 μm or less. Is preferred. Because, under such conditions, by applying, spraying, dipping, or the like, the predetermined rust-preventive oil, it is possible to reduce the variation in sliding friction between the large end surface of the roller and the large flange surface of the inner ring. As a result, variation in the rotational torque value of the tapered roller bearing is reduced, and the range between the maximum value and the minimum value can be stabilized.

[0036]

Examples [Examples 1 and 2 and Comparative Examples 1 and 2] A rust preventive oil having a kinematic viscosity (25 ° C.) shown in Table 1 was applied to the following tapered roller bearings and the like, and the rotation torque ( N ・ cm) 100
The measurement was carried out a number of times at a rotation speed of not more than rpm, and the dispersion of the measured rotation torque was examined. The results are shown in Table 1.・ Bearing dimensions (mm): inner diameter φ41.275 × outer diameter φ82.
550 × width 26.543 ・ Roller large end surface roughness: 0.08 μmRa ・ Inner ring large collar surface roughness: 0.1 μmRa ・ Axial load (preload): 5000N

[0037]

[Table 1]

As is clear from the results shown in Table 1, the tapered roller bearing using a rust-preventive oil having a kinematic viscosity larger than a predetermined range as in Comparative Example 2 has a large variation in rotational torque of 70. there were.

On the other hand, tapered roller bearings using rust preventive oil having a kinematic viscosity within a predetermined range as in Examples 1 and 2 are as follows:
The variation of the rotation torque was within a narrow range of 15 to 50.

Comparative Examples 3 to 5 The kinematic viscosities (25
℃) rust preventive oil is applied to the following tapered roller bearings to make it adhere, the axial load (Fa) is set to 5 kgf, and the atmosphere 2
The number of rotations until the assembly width became constant at 5 ° C. and an inner ring rotation number of 15 rpm was examined. The results are shown in Table 2.・ Bearing dimensions (mm): inner diameter φ45.230 × outer diameter φ79.
985 × width 19.862 ・ Roller large end surface roughness: 0.08 μmRa ・ Inner ring large flange surface roughness: 0.1 μmRa ・ Axial load (preload): 50N

[0041]

[Table 2]

As is clear from the results shown in Table 2, Comparative Example 3 was a tapered roller bearing using a rust-preventive oil whose kinematic viscosity was not within a predetermined range (20 to 50 mm ² / s). Eleven rotations are required until the large end face and the large collar surface of the inner ring come into contact with each other to stabilize the assembling width, and the assembly process of the bearing cannot be simplified.

In Comparative Examples 4 and 5 using a rust-preventive oil having a kinematic viscosity larger than a predetermined range, the number of rotations was relatively small such as 9 and 6 before the assembly width was stabilized. Since the variation in the rotational torque is large as in Comparative Example 2, all the desired effects of the present invention could not be achieved.

Examples 3, 4 and Comparative Example 6 Rust preventive oils having kinematic viscosities (25 ° C.) shown in Table 3 and shown below were sealed in the following tapered roller bearings, and the tapered roller bearings (10 each) were used. To 1,
Heat (60-70 ° C) and allow to cool for 2, 8, 3, and 3 hours
(Surface temperature: about 25 ° C.), and a simulated use experiment consisting of a heating and standing step assuming the following kinematic viscosity change rate was performed.

In this experiment, the relationship between the total heating time and the rotational torque was examined, and the results are shown in FIG. Also,
The kinematic viscosity change rate shown above and shown in Table 3 is the kinematic viscosity change rate.
(%) = (Change in kinematic viscosity after one year / initial kinematic viscosity) × 1
00 is assumed.

Anti-rust oil of Example 3: manufactured by Cast Roll Co .:
482/12 (VCI) (rust inhibitor oil containing petrolatum as a main component, 23 mm ² / s) Rust preventive oil of Example 4: manufactured by NS Lubricants Co., Ltd .: Lastcoat 691 (P) (rust inhibitor oil containing petrolatum as a main component, 48 mm ² / s) Antirust oil of Comparative Example 6: Nippon Oil Co., Ltd .: Antilast P-2
300 (petrolatum is non-compounded NP-3-2 (JIS
K 2246), rust preventive oil, 7.5 mm ² / s) ・ Bearing dimensions (mm): inner diameter φ41.275 × outer diameter φ82.
550 × width 26.543 ・ Roller large end surface roughness: 0.08 μmRa ・ Inner ring large collar surface roughness: 0.1 μmRa ・ Axial load (preload): 50N

[0047]

[Table 3]

As is clear from the results shown in Table 3 and FIG. 1, the tapered roller bearing of Comparative Example 6 used 7.5 mm ² / s of rust-preventive oil which was less than the predetermined kinematic viscosity range. The rate of change in viscosity exceeded 20%, and the rate of change in rotational torque also dropped sharply after heating for a total of 3 hours.

On the other hand, the tapered roller bearings of Examples 3 and 4 used a rust-preventive oil in a predetermined kinematic viscosity range, so that the kinematic viscosity change rate was 20% or less, and after heating for a total of 17 hours. Until then, the rate of change of the rotational torque was small.

In addition to the above test results, Example 3
When evaluating the kinematic viscosity, the kinematic viscosity change rate, and the rotation torque by enclosing the rust-preventive oil of Example 4 in a tapered roller bearing, examine the aging of the rust-preventive oil and the grease when the grease is filled, and the change over time of the rotational torque. Was. In addition, the same tests as in Comparative Examples 3 to 5 were performed to observe the settling of the assembly width (stable number of rotations). The results are summarized in Table 4.

[0051]

[Table 4]

As is clear from the results shown in Table 4, the amount of rust-preventive oil deposited on the tapered roller bearing was 0.8 to 1.1 mg /
Under the condition of cm ² , it is possible to prevent the grease mixed with rust-preventive oil from flowing out, to ensure the stability of the rotating torque when the preload is set, and to reduce the number of rotations at which the assembly width is settled down. found.

[0053]

As described above, the tapered roller bearing according to the present invention relates to a tapered roller bearing in which a large end surface of a tapered roller is guided by a flange provided on the inner ring in a state where a preload is applied. The kinematic viscosity at 25 ° C inside the bearing is 20-50m
Since m ² / s of rust-preventive oil is applied, even when rotating at a low speed such as 100 rpm or less, a stable and accurate measured value of the rotating torque can be obtained. There is an advantage that the tapered roller bearing has a stable dimension.

Further, the tapered roller bearing in which the surface roughness of the large end surface of the tapered roller and the large flange surface of the inner ring is set to be equal to or less than a predetermined value has more excellent rotational torque stability.

The tapered roller bearing using a rust-preventive oil having a kinematic viscosity change rate of 20% or less under a predetermined condition can accurately set and control the preload according to the rotational torque value, and can stably and accurately rotate even at a low speed. The measured value of the torque is obtained.

Any of the tapered roller bearings described above has an advantage that it can be applied as a tapered roller bearing for supporting a pinion shaft of an automobile differential gear.

Further, in the tapered roller bearing, in the invention in which the amount of the rust-preventive oil is set within a predetermined range, it is possible to prevent the grease mixed with the rust-preventive oil from flowing out, and to reduce the grease life due to the mixture of the rust-preventive oil and the grease. Therefore, the stability of the torque can be ensured, so that there is no need to change the type and amount of the rust-preventive oil according to the application of the tapered roller bearing, so that the versatility can be obtained. In addition, such tapered roller bearings can be said to contribute to environmental protection such as working environment since the number of man-hours required for management is small, so that the cost of manufacturing the bearings can be suppressed, and the amount of rust preventive oil used is small. .

Further, the invention relating to the method for setting a preload of a tapered roller bearing according to the present invention is a method for rotating a tapered roller bearing in which a large end surface of a tapered roller and a large flange surface of an inner ring slidably contacting the large end surface have a predetermined surface roughness. When adjusting the preload while measuring the torque, the bearing is lubricated with a rust-preventive oil having a kinematic viscosity at 25 ° C. of 20 to 50 mm ² / s. However, there is an advantage that the method is a preload setting method for a tapered roller bearing in which a stable and accurate rotational torque value can be obtained, and the preload can be accurately set and managed by the rotational torque value.

[Brief description of the drawings]

FIG. 1 is a table showing a relationship between a use state and a rotational torque of a tapered roller bearing of an example and a comparative example.

FIG. 2 is a sectional view of a tapered roller bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Inner ring 1a Large collar surface 2 Outer ring 3 Roller 3a Large end surface 4 Cage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) F16C 33/58 F16C 33/58 43/04 43/04

Claims (7)

[Claims] 1. A tapered roller arranged between a raceway surface of an outer ring and a raceway surface of an inner ring, and a retainer for rotatably holding the tapered roller, wherein the tapered roller is loaded with a preload. In a tapered roller bearing whose large end face is guided by a flange provided on the inner ring, a kinematic viscosity at 25 ° C. within the tapered roller bearing is 20 to 50 m.
A tapered roller bearing to which m ² / s of rust-preventive oil is adhered. 2. The surface roughness Ra of the large end surface of the conical roller is 0.1 μm or less, and the surface roughness Ra of the large collar surface of the inner ring slidably contacting the large end surface is 0.2 μm or less. 2. The tapered roller bearing according to 1. 3. The rust preventive oil according to claim 1, wherein when the rust preventive oil is kept in a bearing at 60 to 70 ° C. for 8 hours and then left to cool for 1 hour, the kinematic viscosity reduction rate is 20% or less. Or the tapered roller bearing according to 2. 4. An adhesion amount of the rust-preventive oil is 0.8 to 1.1 mg.
/ Cm ² , the tapered roller bearing according to any one of claims 1 to 3. 5. The tapered roller bearing according to claim 1, wherein the tapered roller bearing is a tapered roller bearing for supporting a pinion shaft of an automobile differential gear. 6. A tapered roller in which the surface roughness Ra of the large end surface of the conical roller is 0.1 μm or less, and the surface roughness Ra of the large collar surface of the inner ring that slides on the large end surface is 0.2 μm or less. In the preload setting method of adjusting the preload while measuring the rotational torque of the bearing when incorporating the bearing, the kinematic viscosity at 25 ° C. within the bearing is 20 to 50 m before the measurement of the rotational torque.
A method for setting a preload of a tapered roller bearing, wherein m ² / s of rust preventive oil is adhered. 7. The preload setting method for a tapered roller bearing according to claim 6, wherein the tapered roller bearing is a tapered roller bearing for supporting a pinion shaft of an automobile differential gear.