JP2008215158A - Rolling bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress generation of noise in a bearing section by suppressing deterioration in roundness of a rolling bearing device. <P>SOLUTION: This rolling bearing device rotatably supports a camshaft in the cylinder head of an engine, and includes a plurality of rolling elements 14; a retainer 16 which positions the rolling elements 14 at equal spaces in a circumferential direction and which rotatably retains the rolling elements 14; a shell-type outer ring 12 configured to store the rolling elements 14 and the retainer 16 and formed with the raceway surfaces of the rolling elements 14 on the inner side thereof; and an outer ring fastening member 20 formed of a material having almost the same coefficient of thermal expansion as the shell-type outer ring 12 and having a press-fit portion into which the shell-type outer ring 12 is press-fitted. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rolling bearing device for rotatably supporting a camshaft in a cylinder head of an engine.

A technique relating to the above-described rolling bearing device is described in Patent Document 1.
As shown in FIG. 5, the rolling bearing 110 of Patent Document 1 is a shell bearing that can be assembled to the journal portion 101 of the camshaft 100 from the outside in the radial direction.
The rolling bearing 110 includes a plurality of rolling elements 111, a two-divided retainer 112 that holds the rolling elements 111, and a two-divided shell-shaped outer ring 113 having a raceway surface of the rolling elements 111. ing. Then, after the cage 112 in the two-divided state is assembled to the journal portion 101 of the camshaft 100 from the outside in the radial direction, the shell-shaped outer ring 113 in the two-divided state is assembled to the outside of the cage 112. Next, when the camshaft 100 is mounted on the cylinder head 200 of the engine, the rolling bearing 110 is fitted into the semicircular recess 201 h of the cylinder head 200. In this state, the rolling bearing 110 is pressed by the semi-annular cap 205, and both sides of the cap 205 are bolted to both sides of the semicircular recess 201 h of the cylinder head 200. As a result, the shell-shaped outer ring 113 of the rolling bearing 110 is tightened from the outside in the radial direction by the semicircular recess 201h of the cylinder head 200 and the cap 205, and the roundness of the rolling bearing 110 is ensured to some extent.

JP 2005-180459 A

  However, in recent years, the cylinder head 200 is mostly made of an aluminum alloy, and the shell-shaped outer ring 113 of the rolling bearing 110 is generally made of a steel plate. For this reason, a gap may be generated between the shell-shaped outer ring 113 and the semicircular recess 201h of the cylinder head 200 and the cap 205 due to the temperature rise of the engine due to the difference in thermal expansion coefficient between the aluminum alloy and the steel plate. As a result, the roundness of the shell-shaped outer ring 113 of the rolling bearing 110 is lowered, and there is a problem that a clearance in the radial direction is increased in the rolling bearing 110 to generate noise.

  The present invention has been made to solve the above-mentioned problems, and the problem to be solved by the present invention is to suppress the reduction of the roundness of the rolling bearing device and to generate noise in the bearing portion. It is to suppress.

The above-described problems are solved by the inventions of the claims.
The invention of claim 1 is a rolling bearing device for rotatably supporting a camshaft in a cylinder head of an engine, wherein a plurality of rolling elements and the rolling elements are positioned at equal intervals in a circumferential direction, A shell-type outer ring having a configuration in which a cage that can be rotatably held, the rolling element and the cage can be accommodated, and in which a raceway surface of the rolling element is formed, and a thermal expansion coefficient substantially equal to that of the shell-type outer ring And an outer ring fastening member having a press-fit portion into which the shell-shaped outer ring is press-fitted.

According to the present invention, the shell-type outer ring is configured to be press-fitted into the press-fit portion of the outer ring tightening member. For this reason, the shell-shaped outer ring receives an equal tightening force in the circumferential direction from the outer side in the radial direction by the outer ring tightening member. Therefore, the roundness of the shell type outer ring is ensured.
Further, since the outer ring tightening member is formed of a material having a thermal expansion coefficient substantially equal to that of the shell type outer ring, no matter how the engine temperature changes, the outer ring tightening member is not between the outer ring tightening member and the shell type outer ring. There will be no gaps. Therefore, the roundness of the shell-shaped outer ring does not decrease due to the temperature change of the engine. Further, even if the cylinder head side expands further due to the temperature rise, the radial clearance in the rolling bearing device does not increase by the action of the outer ring tightening member. For this reason, it becomes difficult to generate noise in the bearing portion.

According to the invention of claim 2, the outer ring tightening member is formed in a cylindrical shape whose inner side is the pressed-in portion, and is fitted into the semicircular concave portion formed in the bearing support portion of the cylinder head from the radial direction. It is configured to be possible.
Thus, the outer ring tightening member is easily formed by forming the outer ring tightening member in a cylindrical shape.
According to a third aspect of the present invention, the outer ring tightening member includes a pair of ribs that project radially outward from an outer peripheral surface of the outer ring tightening member and are arranged on the same plane, In a state where the member is fitted in the semicircular recess of the bearing support portion of the cylinder head, the pair of ribs are fixed to the upper surface of the bearing support portion provided on both sides of the semicircular recess. It is characterized by being.
That is, since the outer ring tightening member can be directly fixed to the bearing support portion of the cylinder head, a semi-annular cap that holds the rolling bearing device is not required. For this reason, the assembly man-hour of a camshaft can be reduced.

  According to the present invention, the roundness of the shell-shaped outer ring does not decrease due to the temperature change of the engine, and the radial gap in the rolling bearing device does not increase, so that noise is hardly generated in the bearing portion.

Next, the best mode for carrying out the present invention will be described with reference to examples.
[Example]
Hereinafter, the rolling bearing device according to the embodiment of the present invention will be described with reference to FIGS.
The rolling bearing device of this embodiment is a bearing device that rotatably supports a camshaft that is assembled to a cylinder head of an engine. FIG. 1 shows a longitudinal sectional view of the rolling bearing device. FIG. 2 is a perspective view showing a camshaft and an engine cylinder head, and FIG. 3 is a front view showing a state in which the rolling bearing device is assembled to the engine cylinder head. FIG. 4 is a front view showing a modified example of the rolling bearing device.
In addition, the X direction, Y direction, and Z direction in the figure represent the width direction, height direction, and front-rear direction (axial direction of the camshaft) of the cylinder head, respectively.

<Regarding Engine Cylinder Head 200 and Camshaft 100>
Before describing the rolling bearing device 1, the cylinder head 200 and the camshaft 100 of the engine will be briefly described with reference to FIG.
The cylinder head 200 of the engine constitutes a ceiling portion of a combustion chamber (not shown) of the engine, and includes an intake valve, an exhaust valve (not shown) for opening and closing the intake port and the exhaust port of the combustion chamber, and these valves. This is a part in which the camshaft 100 (see FIG. 2A) to be operated is incorporated. On the upper surface side of the cylinder head 200 (opposite to the combustion chamber), as shown in FIG. 2B, a bearing support portion 201 that supports the rolling bearing device 1 of the camshaft 100 is provided in the front-rear direction (Z In the direction). The bearing support portion 201 is formed in a vertical wall shape extending in the width direction (X direction), and a semicircular recess 201 h into which the lower half of the rolling bearing device 1 is fitted is formed on the upper portion of the bearing support portion 201. . Further, as shown in FIG. 3, an upper flat surface 201u is formed on both sides in the width direction of the semicircular concave portion 201h of the bearing support portion 201, and the upper half of the rolling bearing device 1 is pressed to the left and right upper flat surfaces 201u. A female screw hole 201w into which the fixing bolt 203 of the semi-annular cap 205 is screwed is formed.

As shown in FIG. 2A, the camshaft 100 includes a shaft main body 101, a plurality of cam lobes 103 that press the intake and exhaust valves in the axial direction, and a rolling bearing that rotatably supports the shaft main body 101. The apparatus 1 is provided. The shaft body 101 is formed with a plurality of cam fixing portions 101c to which the cam lobe 103 is fixed at predetermined positions and a plurality of journal portions 101j to which the rolling bearing device 1 is mounted.
The camshaft 100 is an assembly type, and is assembled in order from the axial direction with respect to the shaft main body 101 so that the cam lobe 103 and the rolling bearing device 1 do not interfere with each other.

<About the rolling bearing device 1>
As shown in FIGS. 1A and 1B, the rolling bearing device 1 includes a shell-type bearing 10 and an outer ring tightening member 20 into which the shell-shaped outer ring 12 of the shell-type bearing 10 is press-fitted. . Here, FIG. 1A is a longitudinal sectional view of the rolling bearing device, and FIG. 1B is a view taken along arrow BB of FIG. 1A (a front view of the rolling bearing device).
The shell-type bearing 10 is a bearing having a thin shell-shaped outer ring 12 that has been pressed, and a long and narrow needle roller 14 that serves as a rolling element, and a cage that holds the needle roller 14 rotatably at equal intervals in the circumferential direction. 16. This shell type bearing 10 does not use an inner ring and uses the outer periphery of the journal portion 101j of the camshaft 100 as a raceway surface.
The shell-shaped outer ring 12 is made of a thin steel plate, and includes an outer ring main body 12m formed in a cylindrical shape and ring-shaped inner flange portions 12f formed on both sides in the axial direction of the outer ring main body 12m. The inner peripheral surface of the outer ring main body 12m is the raceway surface of the roller 14.
Further, the projecting dimension of the inner flange portion 12f from the raceway surface of the outer ring main body 12m is set to a value sufficiently smaller than the diameter dimension of the needle roller 14. For this reason, in a state where the outer peripheral surface of the needle roller 14 is in contact with the outer peripheral surface of the journal portion 101j of the camshaft 100, the inner peripheral end (protruding end) of the inner flange portion 12f and the outer peripheral surface of the journal portion 101j. A predetermined gap is formed between them.

The cage 16 is made of a thin steel plate and is formed in a cylindrical shape, and has a plurality of pockets 16p at equal intervals in the circumferential direction. The pocket 16p is formed in a slit shape extending in the axial direction, and the needle roller 14 is fitted in a rollable state from the outer peripheral side. Further, in the retainer 16, the central portion in the axial direction of each plate portion 16b located between adjacent pockets 16p protrudes inward in the radial direction, and the interval between the protruding portions is slightly narrowed. Thereby, the needle roller 14 is prevented from falling off inward in the radial direction.
The cage 16 fitted with the needle roller 14 is accommodated from the axial direction in a shell-shaped outer ring 12 having an inner flange portion 12f formed on one end side. The shell-shaped bearing 10 is completed by bending the inner flange portion 12f on the other end side of the shell-shaped outer ring 12 in which the needle roller 14 and the cage 16 are housed.

As shown in FIGS. 1A and 1B, the outer ring tightening member 20 is a steel cylindrical body, and is set to have the same axial length as that of the shell-shaped outer ring 12. The inner diameter dimension of the outer ring tightening member 20 is set to a dimension capable of press-fitting the shell-type bearing 10. The wall thickness of the outer ring tightening member 20 is set to a wall thickness that can ensure sufficient strength to prevent deformation even when the shell-type bearing 10 is press-fitted.
Then, the rolling bearing device 1 is completed in a state where the shell-shaped bearing 10 is press-fitted into the outer ring tightening member 20. That is, the inner side of the outer ring fastening member 20 corresponds to the pressed-in portion of the present invention.
As shown in FIG. 3, the rolling bearing device 1 is attached to the journal portion 101 j of the camshaft 100, and the lower half of the rolling bearing device 1 is a semicircular recess 201 h of the bearing support portion 201 of the cylinder head 200. It is inserted in. In this state, the upper half of the rolling bearing device 1 is pressed by the semi-annular cap 205, and both ends of the cap 205 are bolted to the upper flat surface 201u of the bearing support 201. Thereby, the camshaft 100 is mounted on the cylinder head 200 in a rotatable state.

<Advantages of the rolling bearing device 1 according to the present embodiment>
According to the rolling bearing device 1 according to the present embodiment, the shell-shaped outer ring 12 is configured to be press-fitted into the cylindrical outer ring fastening member 20. For this reason, the shell-shaped outer ring 12 receives a uniform tightening force in the circumferential direction from the outer side in the radial direction by the outer ring tightening member 20. Therefore, the roundness of the shell-shaped outer ring 12 is ensured.
Further, since the outer ring tightening member 20 is formed of a material (steel material) having a thermal expansion coefficient substantially equal to that of the shell-shaped outer ring 12, no matter how the engine temperature changes, the outer ring tightening member 20 and There is no gap between the outer shell 12 and the shell-shaped outer ring 12. Therefore, the roundness of the shell-shaped outer ring 12 does not decrease due to the temperature change of the engine. Further, even if the cylinder head 200 side expands further due to the temperature rise, the radial clearance in the rolling bearing device 1 is not increased by the action of the outer ring tightening member 20. For this reason, it becomes difficult to generate noise in the bearing portion.
Further, since the outer ring tightening member 20 is a cylindrical body, the outer ring tightening member 20 can be easily manufactured.

<Example of change>
Here, the present invention is not limited to the above-described embodiment, and can be modified without departing from the gist of the present invention. For example, in the present embodiment, an example in which the outer ring tightening member 20 is manufactured in a cylindrical shape has been shown. However, as shown in FIG. 4, the cylindrical outer ring tightening member 20 can be modified. That is, a pair of ribs 25 projecting outward in the radial direction are provided on both radial sides of the outer ring tightening member 20, and bolt holes 25 h are formed in these ribs 25, so that the outer ring tightening member 20 is a bearing of the cylinder head 200. It becomes possible to bolt to the support part 201 directly. Thereby, the semi-annular cap 205 becomes unnecessary, and the number of assembling steps of the camshaft 100 can be reduced.
It is also possible to form irregularities on the outer peripheral surface of the cylindrical outer ring tightening member 20 to prevent the rolling bearing device 1 from rotating with respect to the semicircular recess 201 h and the semi-annular cap 205 of the bearing support 201. .
Moreover, in this embodiment, although the rolling bearing apparatus 1 which uses the needle roller 14 was illustrated, the kind of rolling element can be changed suitably.

It is the longitudinal cross-sectional view (A figure) of the rolling bearing apparatus which concerns on the Example of this invention, and the BB arrow line view of A figure (front view of a rolling bearing apparatus) (B figure). It is a perspective view (A figure) of a cam shaft, and a perspective view (B figure) of a cylinder head of an engine. It is a front view showing the state which assembled | attached the rolling bearing apparatus to the cylinder head of the engine. It is the front view (A figure) and top view (B figure) showing the example of a change of a rolling bearing apparatus. It is a perspective view showing the conventional rolling bearing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Rolling bearing apparatus 12 ... Shell-type outer ring 14 ... Needle roller (rolling element)
16 .... Retainer 20 ... Outer ring tightening member 25 ... Rib 100 ... Cam shaft 200 ... Cylinder head 201 ... Bearing support portion 201h ... Semicircular recess 201u・ Upper plane

Claims (3)

A rolling bearing device for rotatably supporting a camshaft in a cylinder head of an engine,
A plurality of rolling elements,
A cage for positioning the rolling elements at equal intervals in the circumferential direction and holding them freely;
A shell-shaped outer ring in which the raceway surface of the rolling element is formed on the inner side in a configuration that can accommodate the rolling element and the cage,
An outer ring tightening member that is formed of a material having a thermal expansion coefficient substantially equal to that of the shell-shaped outer ring, and includes a press-fit portion into which the shell-shaped outer ring is press-fitted,
A rolling bearing device comprising: A rolling bearing device according to claim 1,
The outer ring tightening member is formed in a cylindrical shape whose inner side is the pressed-in portion, and is configured to be fitted in a semicircular recess formed in the bearing support portion of the cylinder head from the radial direction. A rolling bearing device characterized by that. A rolling bearing device according to claim 2,
The outer ring tightening member includes a pair of ribs that protrude radially outward from the outer peripheral surface of the outer ring tightening member and are arranged on the same plane.
The pair of ribs is fixed to the upper surface of the bearing support provided on both sides of the semicircular recess while the outer ring tightening member is fitted in the semicircular recess of the bearing support of the cylinder head. A rolling bearing device characterized by having a configuration.

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