JP2008196691A - Rolling bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rolling bearing for satisfying both reduction of torque and extension of life of the rolling bearing at the same time even in the case where misalignment larger than an inclination angle generally allowed for a bearing while a radial load is applied. <P>SOLUTION: The rolling bearing is provided with rolling elements between raceways formed on an outer circumference surface of an inner member and an inner surface of an outer member, and is usable while the radial load is applied and mutual shaft cores of the inner and outer members are inclined more than 0.1 degree. A radial clearance Δ (mm) of the rolling bearing has the following relation; d<SB>m</SB>×10<SP>-3</SP><Δ< 2d<SB>m</SB>×10<SP>-3</SP>, wherein d<SB>m</SB>(mm) is a pitch circle diameter. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing, and more particularly, to a rolling bearing for an automobile engine with a low torque and a long life.

  In recent years, rolling bearings tend to be used in place of plain bearings as bearings for supporting a crankshaft or the like of an automobile engine. It is known that a rolling bearing has a lower rotational torque at high speed rotation than a sliding bearing. However, when a radial load is applied and misalignment can occur in the rolling bearing due to poor mounting due to the processing accuracy of the engine housing, such as a rolling bearing used to support a crankshaft, misalignment becomes large (generally (Misalignment greater than the tilt angle allowed for the bearing), bearing life is extremely reduced, and rotational torque increases rapidly.

Conventional rolling bearings are known in which the internal dimensions of the bearing are managed to achieve high efficiency and low torque at high speed rotation (see, for example, Patent Document 1).
JP 2001-90736 A

  However, in the rolling bearing described in Patent Document 1, although the internal dimensions of the bearing are controlled, it is not possible to solve the decrease in the bearing life and the increase in the rotational torque due to the misalignment at the same time.

  The present invention has been made in view of the above circumstances, and its purpose is to provide a rolling bearing even when a misalignment exceeding a tilt angle generally allowed for the bearing occurs in a state where a radial load is applied. An object of the present invention is to provide a rolling bearing that satisfies both a low torque and a long life.

The above object of the present invention is achieved by the following configurations.
(1) A rolling element is disposed between the outer peripheral surface of the inner member and the raceway surfaces formed on the inner peripheral surface of the outer member, and the inner and outer members are loaded with a radial load. A rolling bearing that can be used in a state in which the axis of each other is tilted by 0.1 [deg] or more,
Radial clearance △ [mm] is of the rolling bearing, the pitch circle diameter when the _d m [mm], characterized in that it has a relationship of ^{_{d m × 10 -3 <△ <}} 2d m × 10 -3 rolling bearing .
(2) The rolling bearing according to (1), which is assembled to an automobile engine.

According to the rolling bearing of the present invention, radial clearance △ [mm] is the pitch circle diameter and _d m [mm], so as to have a relation of ^{_{d m × 10 -3 <△ <}} 2d m × 10 -3 Since it is set, even if misalignment exceeding the tilt angle generally allowed for bearings due to mounting failure with a radial load applied, etc., while preventing a sudden increase in rotational torque, In addition, the service life is not drastically reduced, and the effect of satisfying both low torque and long service life can be obtained at the same time.In addition, the displacement amplitude of the inner member or outer member related to the rolling element passing vibration can be misaligned. It can be suppressed to about the same level as the case where there is not.

  Hereinafter, a rolling bearing according to an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a partial sectional view of a crankshaft of an automobile engine to which a roller bearing that is a rolling bearing of the present invention is assembled. The crankshaft 1 is an integral type that connects a plurality of connecting rods 2, and is rotatably supported by the crankcase 3 via roller bearings 10.

  As shown in FIGS. 1 and 2, the roller bearing 10 includes an outer ring 11 that is an outer member having an inner member constituted by a crankshaft 1, fitted in the crankcase 3, and having a raceway surface 11 a on the inner peripheral surface. The roller 12 that is a rolling element disposed between the raceway surface 1a formed on the outer peripheral surface of the crankshaft 1 and the raceway surface 11a of the outer ring 11, and the rollers 12 are held at substantially equal intervals in the circumferential direction. And a cage 13.

Here, in an automobile engine, a tilt angle (0.0012 rad) or more generally allowed for a bearing due to a mounting failure or the like in a state where a radial load is applied, for example, as shown in FIG. There is a case where misalignment occurs in which the axial axes x ₁ and x ₂ of each other are inclined by 0.1 [deg] or more.

For this reason, in this embodiment, the influence of radial clearance and misalignment on the rotational torque obtained by calculation, the influence of radial clearance and misalignment on the service life, and the radial clearance and error on the amplitude of the inner ring (or outer ring) displacement. the relationship between the alignment of the impact, the radial clearance △ [mm] of the roller bearing 10, the pitch circle diameter and _d m [mm], has a relationship of ^{_{d m × 10 -3 <△ <}} 2d m × 10 -3 Set as follows. As a result, while preventing a sudden increase in rotational torque, the service life will not be drastically reduced, and the rolling element passing vibration caused by displacement of the inner ring or outer ring will be approximately the same as that without misalignment. Thus, the effect of satisfying both low torque and long life can be obtained. Can not be radial clearance △ obtain the effect of reduction and lifetime increase in the rotational torque to be equal to or smaller than d _m × 10 ^-3, also the radial clearance △ is a 2d _m × 10 ^-3 or more, during high-speed rotation The vibration of the abruptly increases.

In addition, this invention is not limited to the said embodiment, A deformation | transformation or improvement etc. are possible suitably.
In the above embodiment, the case where the outer ring, which is the outer member, is tilted by 0.1 deg or more with respect to the crankshaft, which is the inner member, but also when the crankshaft is tilted by 0.1 deg or more with respect to the outer ring. The effects of the present invention can be obtained by setting the radial clearance.
Moreover, in the said embodiment, although the inner member was made into the crankshaft, you may comprise an inner member by the inner ring | wheel externally fitted by the crankshaft. Further, the outer member may constitute a raceway surface in the crankcase 3 without providing an outer ring.

Furthermore, in the above embodiment, the inner ring, the outer ring, and the cage have been described as an integrated roller bearing. However, the present invention provides a roller bearing in which the inner ring, the outer ring, and the cage are divided into two (or more than three). It can also be applied to. Further, the divided roller bearing is configured to be set to the radial clearance of the present invention when assembled to the shaft.
For example, in the case of a roller bearing divided into two parts, as shown in FIG. 4 (a), after the non-divided annular outer ring 20 is manufactured, it may be divided by means such as discharge, or FIG. As shown in (b), the two plate members 21 may be curved by press molding, and the outer ring 11 may be configured by combining them. In addition, an inner ring | wheel and a holder | retainer can be comprised similarly.

  Hereinafter, using the roller bearing 10 as shown in FIG. 2, rolling friction, sliding friction and lubricant in the bearing when the misalignment size (0 deg to 0.3 deg) and the radial clearance are changed are described. Calculation of rotational torque due to the resistance of the inner ring, calculation of life considering internal stress, and calculation of amplitude of inner ring displacement were performed.

  In Example 1, a roller bearing 10 having a pitch circle diameter of 28 mm (a hole diameter of 31 mm, a shaft diameter of 25 mm, a width of 20 mm, a roller diameter of 3 mm, a roller length of 15.8 mm, and a cage and roller having 18 rollers) is used. The radial load was 2000 N (10% of the rated load), the shaft rotational speed was 3000 rpm, and the rotational torque, life, and inner ring displacement amplitude were calculated. The results are shown in FIGS.

  In Example 2, the roller bearing 10 has a pitch circle diameter of 45.5 mm (a hole diameter of 48 mm, a shaft diameter of 43 mm, a width of 17 mm, a roller diameter of 2.5 mm, a roller length of 15.0 mm, and a cage and roller with 34 rollers). The rotational torque, life, and inner ring displacement amplitude were calculated with a radial load of 2000 N (10% of the rated load) and a shaft rotational speed of 3000 rpm. The results are shown in FIGS.

  In Example 3, the roller bearing 10 has a pitch circle diameter of 52.5 mm (hole diameter 55 mm, shaft diameter 50 mm, width 30 mm, roller diameter 2.5 mm, roller length 25.8 mm, cage and roller with 37 rollers). The rotational torque, life, and inner ring displacement amplitude were calculated with a radial load of 4000 N (10% of the rated load) and a shaft rotational speed of 3000 rpm. The results are shown in FIGS.

As shown in FIGS. 5, 8, and 11, in any of the embodiments, the rotational torque tends to increase as the radial clearance decreases, but the misalignment is relatively large (about 0.3 deg or more). When the radial clearance approaches 0, it can be seen that the rotational torque changes abruptly. On the other hand, as shown in FIGS. 6, 9, and 12, in any of the examples, when the misalignment is relatively small (about 0.1 deg or less), the calculation life gradually decreases as the radial clearance increases. Although there is a tendency, it can be seen that when the misalignment is relatively large, when the radial clearance approaches zero, the misalignment decreases significantly. Furthermore, as shown in FIGS. 7, 10, and 13, in any of the embodiments, the amplitude of the inner ring displacement related to the magnitude of the rolling element passing vibration tends to gradually increase with an increase in the radial clearance. I understand that. In addition, the solid line, the alternate long and short dash line, and the broken line in the figure are straight lines plotted by the least square method with respect to the calculated values of 0.1 deg and 0.3 deg without misalignment, respectively. It can be seen that the slope of the straight line is greatly different from the value 2d _m × 10 ⁻³ as a boundary. That is, if the value of the radial clearance is greater than 2d _m × 10 ^-3, the amplitude of the inner ring displacement seen to abruptly increase with increasing radial clearance (rolling element passing vibrations suddenly becomes large). On the other hand, if the value of the radial clearance is smaller than 2d _m × 10 ^-3, the amplitude of the inner ring displacement although gradually increases with increasing radial clearance, the amount of change is misalignment that no misalignment (0. 1 deg and 0.3 deg) are almost the same. In addition, the above has confirmed that it becomes the same tendency also in the rotational speed of a shaft 1000rpm-6000rpm.

It is a fragmentary sectional view which shows the crankshaft with which the rolling bearing of this invention was assembled | attached. It is a side view of the rolling bearing of this invention. It is a fragmentary sectional view exaggeratingly showing the state where misalignment acted on the rolling bearing of the present invention. A method for manufacturing a split-type rolling bearing is shown. (A) shows a method for manufacturing a ring-shaped and then divided product, and (b) shows a method for manufacturing a plate material by bending it. 3 is a graph showing the influence of radial clearance and misalignment on rotational torque in Example 1. 4 is a graph showing the influence of radial clearance and misalignment on the life in Example 1. It is a graph which shows the influence of the radial clearance and the misalignment which acts on the amplitude of the inner ring displacement in the first embodiment. It is a graph which shows the influence of the radial clearance and the misalignment which acts on the rotational torque in Example 2. It is a graph which shows the influence of the radial clearance and the misalignment which acts on the lifetime in Example 2. It is a graph which shows the influence of the radial clearance and the misalignment which acts on the amplitude of the inner ring | wheel displacement in Example 2. FIG. It is a graph which shows the influence of the radial clearance and the misalignment which acts on the rotational torque in Example 3. It is a graph which shows the influence of the radial clearance and the misalignment which acts on the lifetime in Example 3. It is a graph which shows the influence of the radial clearance and the misalignment which acts on the amplitude of the inner ring displacement in Example 3.

Explanation of symbols

1 Crankshaft (inner member)
10 Rolling bearing 11 Outer ring (outer member)
12 Roller (rolling element)
13 Cage

Claims (2)

A rolling element is disposed between the outer peripheral surface of the inner member and the raceway surfaces formed on the inner peripheral surface of the outer member, and the inner member and the outer member are in a state of being loaded with a radial load. A rolling bearing that can be used in a state in which the shaft core is tilted by 0.1 [deg] or more,
Radial clearance △ [mm] is of the rolling bearing, the pitch circle diameter when the _d m [mm], characterized in that it has a relationship of ^{_{d m × 10 -3 <△ <}} 2d m × 10 -3 rolling bearing .   The rolling bearing according to claim 1, wherein the rolling bearing is assembled to an automobile engine.

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