Abstract
This utility model discloses a refined oilstone with logarithmic convexity tapered roller. The two sides of the rectangular oil stone in the length direction are composed of inwardly concave surfaces, which have the same shape and are symmetrically distributed. The third side of the rectangular oil stone in the length direction is a concave surface with the same radius and taper as the tapered roller. The grinding theory holds that the amount of workpiece cutting is directly proportional to the contact arc length. Design the oil stone structure based on the calculated logarithmic convexity curve, and obtain the required logarithmic convexity after grinding the oil stone. The use of this structure for processing roller convexity requires simple processing equipment, low cost, and easy operation, which solves the problem of difficult and high cost processing of logarithmic convexity rollers and has high engineering value and economic benefits.
Description
A logarithmic convexity tapered roller refined oilstone
Technical field
This utility model relates to an oilstone used for processing convex rollers, particularly to a logarithmic convex mesh cone roller precision grinding oilstone.
Background technology
The contact between the finite length roller and the raceway causes stress concentration at the end of the roller, thereby reducing the fatigue life of the rolling bearing. Roller shaping design can improve the load-bearing capacity and fatigue life of rolling bearings, so the selection of roller convexity and calculation of convexity measurement have become one of the key issues. Roller convex types generally include straight line type, arc semi convex type, arc fully convex type, modified line type, and logarithmic type. The logarithmic type is currently considered the most ideal roller convex type, but its processing difficulty and high cost make it difficult to be widely used in engineering.
Summary of the invention
The purpose of this utility model is to overcome the shortcomings of the existing technology and provide a precision grinding oilstone for logarithmic convex tapered rollers, which is suitable for processing logarithmic convex tapered rollers.
The technical solution adopted by this utility model is:
The two sides of the rectangular oil stone in the length direction are composed of inwardly concave surfaces, which have the same shape and are symmetrically distributed. The third side of the rectangular oil stone in the length direction is a concave surface with the same radius and taper as the tapered roller.
The projection curve equation of the concave surface on the bottom plane is:
In the formula: x - coordinate along the axis of the tapered roller; Y - radial coordinates along the tapered roller; δ (x) - amount to be ground; KC - Grinding coefficient; R (x) - radius of tapered roller.
The grinding theory holds that the amount of workpiece cutting is proportional to the contact length. Therefore, by designing the oilstone structure, the purpose of controlling the contact arc length between the oilstone and the roller can be achieved, and the logarithmic convexity of the roller can be machined. The design steps are as follows:
The amount to be ground δ (x) is obtained from the roller convexity value T (x), and the relationship between the amount to be ground and the contact arc length is as follows:
δ(x)＝kcL(x)
In the formula: L (x) - contact arc length, and L (x)=θ (x) R (x), where θ (x) is the circumferential angle corresponding to the circumferential contact arc length between the roller and the oilstone during grinding.
Calculate the contact angle θ (x):
From this, it can be concluded that the projection curve 7 of the front surface 3 on the bottom plane has the following equation:
The projection curve 8 of the back surface 5 on the bottom plane and the projection curve 7 of the front surface 3 on the bottom plane are symmetrical about x. The curvature radius of the projection curve 9 of the A-A cross-sectional view of the upper surface 1 on the side plane is the tapered roller radius R (x).
The beneficial effects of this utility model are:
1. The required processing equipment is simple, cost-effective, and easy to operate;
2. It can process any given logarithmic convexity tapered roller, solving the current difficult and costly problem of logarithmic convexity processing;
3. This structural oilstone can ensure that its original processing performance can be maintained after a period of use without affecting processing accuracy.
Attached image description
Figure 1 is a schematic diagram of the oilstone structure for precision grinding of logarithmic convex tapered rollers.
Figure 2 is the front view of Figure 1.
Figure 3 is a cross-sectional view taken along the line A-A of Figure 2.
Figure 4 is a top view of Figure 1.
Figure 5 is an enlarged schematic diagram of the logarithmic busbar of the tapered roller obtained by processing the oil stone according to the present invention.
In the figure: 1. Upper surface; 2. Left side plane; 3. Front surface; 4. Right side plane; 5. Rear surface; 6. Lower plane; 7. The projection curve of the front surface 3 on the bottom plane; 8. The projection curve of the back surface 5 on the bottom plane; 9. The projection curve of the A-A cross-sectional view of surface 1 on the side plane.
Specific implementation method
The present utility model will be further explained in conjunction with the accompanying drawings and specific embodiments.
As shown in Figure 1, the two sides of the rectangular oil stone in the length direction are composed of an inward concave front surface 3 and an inward concave rear surface 5. The two surfaces have the same shape and are symmetrically distributed. The third side of the rectangular oil stone in the length direction is the upper surface 1, which is concave with the same radius as the tapered roller. The left plane 2, right plane 4, and lower plane 6 are all planes. 7 is the projection curve of the front surface 3 on the bottom plane, 8 is the projection curve of the rear surface 5 on the bottom plane, and 9 is the projection curve of the A-A cross-sectional view of the upper surface 1 on the side plane.
The large end diameter of the tapered roller is 20mm, the small end diameter is 13.418mm, and the length is 25mm. In this example, Lundberg proposed the famous Lundberg convexity formula in 1939, which is as follows:
θ 1, θ 2- half angle of contact between the roller and the inner and outer raceways; A1, a2- Large end radius and small end radius of cone; Q - Load; R (x) - roller radius at any cross-section; E1, E2- elastic modulus of roller and raceway materials; V1, v2- Poisson's ratio of roller and raceway materials; T (x) - convexity value of tapered roller.
In the previous process, the two ends of the roller were chamfered at a 45 ° angle with a distance of 2mm. Therefore, when designing the oilstone, only the convexity at x ∈ [2, 23] was designed, corresponding to R (x) ∈ [6.972, 9.737]. θ1＝21.311°,θ2＝13.811°, a1＝6.709mm,a2＝10mm,Q＝2kN,E1＝E2＝206GPa,v1＝v2＝0.3. Substituting the convexity formula yields:
From the above equation, Tmax=0.0167, therefore the amount to be ground is
Considering a machining allowance of 0.003mm, the actual amount to be ground is
Take kc=0.0034, according to the formula
The equation for curve 7 in Figure 2 (c) is
The projection curve 8 of the rear surface 5 on the bottom plane in Figure 4 is symmetrical about the x-axis with respect to the projection curve 7 of the front surface 3 on the bottom plane. The curvature radius of the projection curve 9 of the A-A cross-sectional view of the upper surface 1 on the side plane is R (x). After grinding the oil stone, an enlarged schematic diagram of the logarithmic generatrix of the tapered roller shown in Figure 5 can be obtained.
The above description is only a specific embodiment of the present utility model, and the present utility model is not limited to the above embodiment. It can be modified in various forms as long as it remains consistent with the technical idea described in the claims. Although this specification discloses the specific implementation scheme of the present utility model, the scope of protection is by no means limited to this, and any modifications made on this basis should be protected by the claims attached to this application.
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