JPH0649363Y2 - Roll neck bearing device for rolling mill - Google Patents

Description

[Detailed Description of the Invention] <Industrial field of application> The present invention relates to a roll neck bearing device for a rolling mill, and more specifically, it forms a roll neck with a step, and this roll neck is used as a roll chock with a roller bearing. The present invention relates to a structure of an inner ring portion of a bearing device that is supported.

<Prior Art> As a roll neck bearing device for a rolling mill, there is conventionally a structure having a structure as shown in FIG.

In the bearing device of the same figure, the roll neck 1 is formed in a stepwise small diameter sequentially from the roll main body 2 side, and a plurality (in this example, 2) is formed.
1) and the diameter portions 1a and 1b. This roll neck 1
Are supported by the roll chock 4 via multi-row roller bearings 3.

The roller bearing 3 constitutes a single bearing over a plurality of radial portions 1a, 1b, but the inner rings 3a, 3b are divided into a plurality of axial portions corresponding to the plurality of radial portions 1a, 1b of the roll neck 1. Has been done. Each inner ring 3a, 3b has a different wall thickness,
By being fitted to the corresponding roll neck diameter portions 1a and 1b, raceway surfaces that are substantially flush with each other are formed on the outer peripheral side.

In the figure, 3c is the outer ring of the roller bearing 3, 3d is the roller, and 5 is the inner ring 3a, 3
A collar for preventing b from coming out and a thrust bearing 6 are provided.

<Problems to be Solved by the Invention> By the way, in assembling the bearing device as described above, first, the inner rings 3a and 3b of the roller bearing 3 are fitted to the respective diameter portions 1a and 1b of the roll neck 1.

Each inner ring 3a, 3b is formed into a dimension that allows for the required interference amount to the corresponding roll neck diameter portion 1a, 1b, and then the diameter portion
It is attached to 1a and 1b by shrink fitting. Due to this shrink fitting, the outer diameters of the inner rings 3a, 3b slightly expand outward in the radial direction. In this case, since the inner rings 3a, 3b have different wall thicknesses, the inner rings 3a, 3b have different outer diameter expansion amounts. Therefore, as shown in FIG. The outer diameters D ₁ and D _{2 of the} inner rings 3a and 3b are different from each other, and a step S is formed on the raceway surface.

If the inner rings 3a, 3b having the step S on the raceway surface are used as they are as a part of the bearing 3, the load distribution of each row of rollers is deviated and the life of the bearing is adversely affected.

For this reason, conventionally, after the shrink fitting of all the inner rings 3a, 3b, co-polishing of the raceway surfaces of these inner rings 3a, 3b has been carried out. Since there is usually no such large-scale polishing equipment, the rolls having the inner rings 3a and 3b attached thereto were conveyed to a roll maker, and the maker carried out co-polishing.

Therefore, co-polishing of the inner ring raceway requires a lot of labor, and the steel mill side has to prepare a spare roll for the operation during that time, which is very troublesome.

The present invention has been made in view of the above problems, and an object of the present invention is to eliminate the need for co-polishing of the raceway surface after the inner ring is shrink-fitted, and to facilitate the assembly work of the bearing device.

<Means for Solving Problems> In order to achieve the above-mentioned object, the present invention adopts the following configuration as a result of carefully considering the circumstances in which a step is formed on the raceway surface of the inner ring by shrink fitting. I chose

The present invention provides a roll neck bearing device for a rolling mill, which has a roll neck formed in a stepwise small diameter sequentially from the roll body side, and a plurality of roller bearing inner rings that are shrink-fitted to the respective diameter portions of the roll neck. In order to make the outer diameter of each inner ring after shrink-fitting substantially flush without co-polishing, the outer diameter or interference amount of the inner ring to be shrink-fitted on the small diameter side of the roll neck is adjusted to the large diameter side. It is characterized in that it is set a predetermined amount larger than the inner ring.

<Operation> When inner rings having different wall thicknesses are fitted by shrink fitting to the multiple diameter portions formed on the roll neck, if the outer diameters of the inner rings are the same, the inner ring with thin wall thickness, that is, the roll neck The inner ring fitted to the large diameter portion is more strongly affected by shrinkage fitting than the inner ring on the small diameter portion side of the roll neck, and largely bulges outward in the radial direction.

However, in the present invention, as described above, the outer diameter or the interference amount of the inner ring on the small diameter portion side is set to be larger by a predetermined amount than the inner ring on the large diameter portion side. The predetermined increase amount of the outer diameter or the interference amount is an amount determined according to the step difference of the raceway surface caused by shrink fitting.

Therefore, the difference in the amount of expansion that occurs between the inner ring on the large diameter side and the inner ring on the small diameter side due to shrink fitting will be corrected by this increase in the outer diameter or interference amount, and the raceways between the inner rings will The step between them can be made small enough to be practically ignored.

<Embodiment> Hereinafter, the present invention will be described in detail based on an embodiment shown in the drawings.

(1) First Embodiment FIGS. 1 and 2 are explanatory views of an embodiment in which the present invention is applied to a roll neck having two large and small diameter portions, and FIG. FIG. 2 shows the state after the inner ring is fitted.

In these figures, 1 indicates the whole roll neck,
1a is a large diameter portion on the roll body side, and 1b is a small diameter portion. Also,
Reference numeral 3a denotes a thin inner ring fitted to the large diameter portion 1a of the roll neck 1, and 3b denotes a thick inner ring fitted to the small diameter portion 1b of the roll neck 1.

The inner rings 3a, 3b form part of a multi-row roller bearing, and the roll neck 1 is supported by the roll chock via the roller bearings, as in the case of the conventional example shown in FIG. Since this is the case, detailed description thereof will be omitted.

The feature of this embodiment is that in the state before shrink fitting, the outer diameter Di _{2 of the} inner ring 3b fitted to the roll neck small diameter portion 1b is larger than the outer diameter Di ₁ of the inner ring 3a on the large diameter portion 1a side. Is also set to a large diameter by a predetermined amount (Di ₁ <Di ₂ ). And, the interference amounts Δd ₁ and Δd _{2 of} the inner rings 3a and 3b, that is, the difference between the inner diameters d ₁ and d ₂ of the inner rings 3a and 3b and the outer diameters of the roll neck diameter portions 1a and 1b corresponding thereto are The inner rings 3a and 3b are set to be the same (Δd ₁ = Δd ₂ ).

Wherein the predetermined increment of the inner ring outer diameter (Di ₂ -Di _1), so that can correct the step of raceway surfaces caused by shrinkage fitting, is an amount calculated determined by formula shown below.

Next, the increase amount (D), which is the difference between the outer diameters Di ₁ and Di ₂ of both inner rings 3a and 3b,
Explain how to calculate i ₂ −Di ₁ ) and its theoretical basis.

Generally, when shrink fitting is performed on the inner neck ring of the roll neck, the outer diameter of the inner ring bulges outward in the radial direction under the influence of the shrink fitting and becomes large. The expansion amount ΔDi of the outer diameter in that case is calculated by the following equation.

ΔDi = {d / (d + 3)} · (d / Di) · Δd Here, d is the inner diameter of the inner ring, Di is the outer diameter of the inner ring, and Δd is the interference amount. Needless to say, this interference amount Δd has a difference between the inner diameter d of the inner ring and the outer diameter of the diameter portion of the roll neck corresponding to this, and if this interference amount Δd is set, the inner diameter of the inner ring d is determined automatically. Also, {d / (d
+3)} is a coefficient indicating the effectiveness of the interference when the shrink fitting surface is a polished surface.

From this formula, if there are multiple inner rings, and the outer diameters of these inner rings are equal to each other and the interference amounts are also equal to each other, the inner ring on the large diameter side has a shrink fit smaller than the inner ring on the small diameter side. It can be seen that it is strongly affected and bulges more radially outward.

Now, returning to FIG. 1, the inner ring on the roll neck large diameter portion 1a side
If the expansion amount of the outer diameter D ₁ of 3a after shrink fitting is expressed as ΔDi ₁ , then D ₁ = Di ₁ + ΔDi ₁

Further, substituting the expression for ΔDi ₁ in this expression, D ₁ = Di ₁ + {d ₁ / (d ₁ +3)} · (d ₁ / Di ₁ ) · Δd ₁ ...

Similarly, for the inner ring 3b fitted to the roll neck small-diameter portion 1b, if the outer diameter after shrinkage fitting is expressed as D ₂ and the expansion amount is expressed as ΔDi ₂ , then D ₂ = Di ₂ + ΔDi ₂ , D ₂ = Di ₂ + {d ₂ / (d ₂ +3)} · (d ₂ / Di ₂ ) · Δd ₂ ...

Here, since the outer diameters D ₁ and D ₂ of both inner rings 3a and 3b after shrink fitting must match each other (D ₁ = D ₂ ), from the above formula and the formula, Di ₁ + ΔDi ₁ = Di ₂ + ΔDi ₂ ………… becomes.

By the way, in this equation, the outer diameters Di ₁ and Di ₂ of the inner rings 3a and 3b before shrink fitting are significantly larger than the expansion amounts ΔD ₁ and ΔD ₂ and are close to each other, so that the expansion amounts ΔD ₁ and Δ
It has little effect on the calculation of D ₂ . Therefore, in the actual calculation, the outer diameters Di ₁ and Di ₂ of both inner rings 3a and 3b before shrinkage fitting are erased from both sides of the equation as being equal to each other.
That is, ΔDi ₁ = ΔDi ₂ ............ This formula is calculated from the formulas as follows: {d ₁ / (d ₁ +3)} ・ (d ₁ / Di ₁ ) ・ Δd ₁ = {d ₂ / (d ₂ +3)} ・ (d ₂ / Di ₂ )・ Δd ₂ …….

Here, if the interference amounts Δd ₁ and Δd ₂ of both inner rings 3a and 3b are set to be equal to each other, the interference amount Δ from both sides of the equation is
The terms d ₁ and Δd ₂ can be eliminated, and {d ₁ / (d ₁ +3)} ・ (d ₁ / Di ₁ ) ＝ {d ₂ / (d ₂ +3)} ・ (d ₂ / Di ₂ ) ...... is obtained, and this is transformed to obtain Di ₂ = (d ₂ / d ₁ ) ² · {(d ₁ +3) / (d ₂ +3)} · Di ₁ …. Therefore, the outer diameter Di of the inner ring 3b on the small diameter portion 1b side
₂ of increased amount (Di ₂ -Di ₁₎ is, Di ₂ -Di ₁ = ^{_{[(d 2 / d 1) 2}} · {(d 1 +3) / (d 2 +3)} - 1 ] · Di ₁ ... and Become.

As described above, the dimensions of both inner rings 3a and 3b (outer diameter Di ₁ , Di ₂ , inner diameter
If d ₁ , d ₂ and interference amount Δd ₁ , Δd ₂ ) are set in advance, each inner ring 3a, 3b is shrink-fitted by shrink fitting, so that each diameter portion 1a,
When fitted to 1b, the difference in outer diameter of each inner ring 3a, 3b
The difference in the amount of expansion will be compensated, and as shown in FIG.
Both outer diameters have the same value D ₀ , and the orbital surfaces are flush with each other.

(2) Second Embodiment FIG. 3 shows another embodiment of the present invention. In this embodiment, the outer diameters Di ₁ and Di ₂ of both inner rings 3a and 3b before shrink fitting are set to be the same (Di ₁ = Di ₂ ), and the interference amount Δd of the inner ring 3b on the small diameter portion 1b side is set. ₂ is set to be larger than the interference amount Δd ₁ of the inner ring 3a on the large diameter portion 1a side by a predetermined amount (Δ
d ₁ <Δd ₂ ). The predetermined increase amount of the interference amount (Δd ₂ −Δ
d ₁ ) is an amount calculated and determined by a predetermined formula so that the step difference of the raceway surface caused by shrink fitting can be corrected.

That is, the above formula; {d ₁ / (d ₁ +3)} · (d ₁ / Di ₁ ) · Δd ₁ = {d ₂ / (d ₂ +3)} · (d ₂ / Di ₂ ) · Δd ₂ ... In, the outer diameters Di ₁ and Di ₂ of both inner rings 3a and 3b are set to be equal to each other. The value of this outer diameter is calculated by setting a formula for one inner ring, for example, the inner ring 3a on the large diameter portion 1a side, and setting the interference amount Δd ₁ for this formula, and calculating this value for the other inner ring. Apply to. In this way, by giving the same value to the outer diameters of both inner rings 3a, 3b, the terms of outer diameters Di ₁ and Di ₂ can be eliminated from both sides of the equation, and the equation is {(d ₁ ) ² / ( d ₁ +3)} ・ Δd ₁ = {(d ₂ ) ² / (d ₂ +3)} ・ Δd ₂ …… and Δd ₂ = (d ₁ / d ₂ ) ²・ {(d ₂ +3) / (d ₁ +3)} · Δd ₁ ... Is obtained.

Therefore, the increased amount (Δd ₂ −Δd ₁ ) of the interference amount of the inner ring 3b on the small diameter portion 1b side is Δd ₂ −Δd ₁ = [(d ₁ / d ₂ ) ²・ {(d ₂ +3) / (d ₁ +3)} − 1] · Δd ₁ ……….

Also in this case, when both inner rings 3a, 3b are shrink-fitted to the respective diameter portions 1a, 1b of the roll neck 1, the difference in interference amount between the inner rings 3a, 3b compensates for the difference in expansion amount. In the same manner as in the above-mentioned embodiment, the orbital surfaces of both are flush with each other.

In each of the above embodiments, the interference amounts Δd ₁ and Δd ₂ are set to be the same between the two inner rings 3a and 3b so that the outer diameters Di ₁ and Di ₂ are different, or the outer diameters Di ₁ and Di ₂ are different. the filtrate amount [Delta] d ₁ showed set ₂ to the same, but so as to vary the [Delta] d _2, both inner rings 3a, among 3b, filtration amount [Delta] d ₁ showed the outer diameter Di _1, Di _2, and [Delta] d ₂ May be set to different values.

<Effect of the Invention> As described above, in the present invention, the shrinkage is likely to affect the shrinkage due to the difference in expansion amount between the inner ring on the large diameter side and the inner ring on the small diameter side. The outer diameter or interference amount of the inner ring on the small diameter side is set larger than the inner ring on the large diameter side of the roll neck by a predetermined amount.Therefore, by increasing the outer diameter or the interference amount, shrink fitting The difference in the amount of expansion that occurs between the inner rings is corrected, and the step between the raceways of the inner rings can be made small enough to be practically ignored. As a result, co-polishing of the raceway surface after shrink-fitting the inner ring is unnecessary, and the assembly work of the bearing device is facilitated.

[Brief description of drawings]

1 and 2 are explanatory views of an embodiment of the present invention. FIG. 1 shows a state before the inner ring is fitted, and FIG. 2 shows a state after the inner ring is fitted. FIG. 3 is an explanatory view of another embodiment and shows a state before the inner ring is fitted. 4 and 5 relate to a conventional example, FIG. 4 is a sectional view of a roll neck portion, and FIG. 5 is an explanatory view showing a state after the inner ring is fitted. 1 ... Roll neck, 1a ... Large diameter part, 1b ... Small diameter part, 3a
…… Inner ring on the large diameter side, 3b …… Inner ring on the small diameter side, Di ₁ , Di ₂
…… Outer diameter, d ₁ , d ₂ …… Inner diameter, Δd ₁ , Δd ₂ …… Amount of interference.

Claims (1)

[Scope of utility model registration request] 1. A roll neck bearing for a rolling mill having a roll neck formed in a stepwise small diameter stepwise from the roll body side, and a plurality of roller bearing inner rings that are shrink-fitted to the respective diameter portions of the roll neck. In the device, the outer diameter or interference amount of the inner ring to be shrink-fitted on the small diameter side of the roll neck is adjusted so that the outer diameter after shrink fitting of each inner ring becomes almost flush without co-polishing. A roll neck bearing device for a rolling mill, which is set to a predetermined amount larger than that of the inner ring of the rolling mill.