JP2004162887A - Cam follower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To allow easy work for fabricating a cam follower and reduce the weight and size without a decrease in loading. <P>SOLUTION: The cam follower comprises a shell roller bearing 13 provided on the outer periphery of a supporting shaft 10 mounted between a pair of side walls 5, 6 opposed to each other in mutually spaced relation. The shell roller bearing 13 consists of an outer ring 11 having collar portions 11b, 11c at both axial ends of a shell cylindrical portion 11a extending to the inner diameter sides and a plurality of rollers 12 arranged on the inner periphery side of the outer ring 11. Desirably, the shell roller bearing is in a total roller shape or has the outer ring 21 whose cylindrical portion 21a has a plate thickness greater than the plate thickness of each of the collar portions 21b, 21c. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention particularly relates to a cam follower using a shell type roller bearing.
[0002]
[Prior art]
A cam follower, for example, a cam follower for a rocker arm, has a support shaft provided between a pair of side walls facing each other at an interval, and a rotating body that comes into contact with the cam via rollers is provided on an outer periphery of the support shaft. (See Patent Document 1). In the related art, the rotating body is generally cut into a shape having no flange at both ends in the axial direction. Many rollers are arranged on the inner peripheral side of the rotating body without the interposition of the retainer.
[0003]
On the other hand, the needle needle roller bearings have a shell-shaped outer ring and a plurality of needle rollers, and are classified into two types, a full roller type without using a cage and a type with a cage. Among these, the outer ring of the full roller shell needle roller bearing comprises a cylindrical portion having an inner peripheral surface as a raceway surface, and a flange portion extending from the axial end of the cylindrical portion to the inner diameter side. It is.
[0004]
The outer ring is usually formed by bending and drawing a single metal plate (thin steel plate) as a raw material to form a bottomed cylinder, and then form the bottomed cylinder. Drilling is performed on the bottom to form a front-bend-side flange portion, and thereafter, a rear-bend-side flange portion is formed at the opening side of the tubular body to finish the structure (see Patent Document 2).
[0005]
[Patent Document 1]
See JP-A-10-280915, specification 0016, and FIG.
[Patent Document 2]
See JP-A-2001-65575, 0005 of the specification, and FIG.
[0006]
[Problems to be solved by the invention]
In the conventional cam follower described above, since the rotating body having no flange and the rollers having no retainer are used, the rollers may be separated at the time of assembling. It is necessary to carry out the assembling work by holding the rollers with the holding tool, which increases the cost, and the assembling work is troublesome and troublesome. Further, the conventional cam follower has a problem that the thickness of each part is large and the weight is relatively heavy.
[0007]
On the other hand, conventional shell-shaped needle roller bearings are mounted by press-fitting the inside diameter of a hole in a housing with a predetermined interference, and are therefore used as outer ring fixed or outer ring non-rotating bearings. Normal. However, looking at the structure, in the case of the full-roller type with an outer ring flange, the grease is applied to the space between the outer ring raceway surface and the entire roller on the bearing inner diameter side, so that the rollers fall out of the outer ring raceway surface. In addition to being held so as not to be disturbed, even when the shaft is inserted into the bearing during assembly, the rollers are received by the flange of the outer ring, so that the rollers move in the axial direction and do not fall off the bearing. Also, it has a large rated load in a small space.
[0008]
Therefore, an object of the present invention is to utilize a structure of a shell-type roller bearing so that during assembly, even without using a roller holder, the rollers are not separated, so that the assembling work can be easily performed, and Another object of the present invention is to provide a cam follower which is lightweight, small and has a large load.
[0009]
[Means for Solving the Problems]
The cam follower of the present invention uses a shell-type roller bearing, and includes a pair of side walls facing each other at an interval, and a support shaft erected between the both side walls. A shell-type roller bearing is provided which includes a shell-shaped outer ring having flange portions extending radially inward at both axial ends of a cylindrical portion, and a plurality of rollers disposed on the inner peripheral side of the outer ring. It is characterized by the following.
[0010]
According to the above configuration, the rollers are held on the inner peripheral side of the outer ring by the flange portion of the outer ring so as not to come out in the axial direction, and if grease is applied to the rollers, the rollers are held on the inner diameter side of the bearing. Therefore, assembly can be performed in a state in which the rollers are separated and not scattered, and it is not necessary to use a roller holder as in the related art, and the assembly operation can be easily and efficiently performed without increasing the cost. Further, since the shell-type roller bearing generally has a large rated load in a small space, a cam follower which is lightweight and small and has a large applied load can be obtained.
[0011]
The shell-type roller bearing in the cam follower having the above configuration may have an outer ring having a flange portion extending to the inner diameter side at both ends in the axial direction, but in order to increase the rated load, the inner roller side of the outer ring may be used. It is preferable that the plurality of rollers be a full-roller type in which the rollers are arranged without passing through a retainer. In a cam follower using a full-roller type shell-type roller bearing, the applied load can be increased without increasing the overall size.
[0012]
Further, in the shell-type roller bearing in the cam follower having the above configuration, it is desirable that the thickness of the cylindrical portion of the outer race be greater than the thickness of any of the flange portions.
[0013]
According to the above configuration, among the portions of the outer ring, the thickness of the cylindrical portion is the thickest, and the thickness of the flange portion is thinner. Therefore, the cylindrical portion has a sufficient thickness, has sufficient strength, and can withstand an impact load applied directly from the cam.
[0014]
In addition, since the thickness of the flange portion is thinner than that of the cylindrical portion, the length of the rollers can be increased by the thinner thickness of the flange portion, and the width of the transfer surface of the rollers can be reduced. Spreads and the rated load increases. Further, since the thickness of the flange portion is reduced, the curvature of the connecting portion between the flange portion and the cylindrical portion is reduced, and the connecting portion does not easily interfere with the end of the roller. By increasing the width of the surface, the rated load can be increased.
[0015]
As described above, the shell-type roller bearing having the above configuration used in the cam follower of the present invention has a large strength against a load applied directly to the outer peripheral surface of the outer ring from the outside, and has a large rated load. It can be used without trouble as a rotating body that the cam directly contacts. Further, if the length of the rollers is fixed, the total width of the bearing is reduced by the thinner flange, which contributes to the downsizing of the cam follower.
[0016]
In the shell-type roller bearing having the above-described configuration, the shell-shaped outer ring is usually manufactured from a single metal plate by a processing step including bending, but may be manufactured by another processing step.
[0017]
A shell-shaped outer ring is manufactured by a processing step including bending from a single metal plate, and a thickness of a flange portion on a front bending side of both flange portions of the outer ring is a plate of a cylindrical portion. If it is thinner than the thickness and the thickness of the flange on the rear bending side is thinner than the thickness of the flange on the front bending side, the flange on the front bending side must be It is only necessary to add a step of reducing the thickness, and a required outer ring can be manufactured relatively easily.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
[Embodiment of cam follower]
FIGS. 1 to 3 show an embodiment of a cam follower of the present invention. In this embodiment, a rocker arm is exemplified as a cam follower. FIG. 1 is a vertical sectional side view of a rocker arm according to an embodiment, FIG. 2 is a plan view of the rocker arm of FIG. 1, and FIG. 3 is a cross-sectional view taken along line (3)-(3) of FIG.
[0019]
In these figures, reference numeral 1 denotes the entire rocker arm, reference numeral 2 denotes a cam, reference numeral 3 denotes a lash adjuster serving as a tilt support portion, and reference numeral 4 denotes a valve.
[0020]
The rocker arm 1 is of an end pivot type and has a body 7 including a pair of side walls 5 and 6 facing each other at an interval. A pivot portion 8 fitted to the upper end of the lash adjuster 3 is provided between one end of the pair of side walls 5 and 6 in the longitudinal direction. A joint 9 is provided.
[0021]
A support shaft 10 is provided between intermediate portions of the side walls 5 and 6 in the longitudinal direction. The support shaft 10 has a shell shape as a rotating body rotatably supported on the outer periphery thereof and abutting on the cam 2. A full roller shell-shaped needle roller bearing 13 comprising an outer ring 11 and a needle roller 12 is provided. Therefore, the shell-shaped needle roller bearing 13 here is an outer ring rotating type bearing having the support shaft 10 as an inner ring, and the cam 2 is in rolling contact with the outer peripheral surface of the shell-shaped outer ring 11.
[0022]
As shown in FIG. 3, in the shell-shaped needle roller bearing 13, the outer ring 11 has a cylindrical portion 11a having an inner peripheral surface as a raceway surface, and extends from both axial ends of the cylindrical portion 11a to the inner diameter side. It consists of flanges 11b and 11c. A large number of the needle rollers 12 are arranged on the inner peripheral side of the outer ring 11 without passing through a retainer.
[0023]
The pair of side walls 5 and 6, the pivot portion 8 and the valve engaging portion 9 are integrally formed of a single plate, but one or both of the pivot portion 8 and the valve engaging portion 9 are provided. May be formed separately from the side walls 5 and 6, and this may be connected to the side walls 5 and 6 by means such as welding.
[0024]
In the above-described configuration, the cam follower portion is assembled by attaching the shell-shaped needle roller bearing 13 to the outer periphery of the support shaft 10. In this assembly, the needle roller 12 is dropped off by the flange portions 11 b and 11 c of the outer ring 11. Since it is held on the inner peripheral side of the outer ring 11 so as not to be disengaged, it is possible to assemble without dislodging the needle rollers 12 without using a conventional roller holder, and the assembling work is easily and efficiently performed. I can do it. Further, since the shell-type roller bearing 13 generally has a large rated load in a small space, it is possible to obtain a cam follower which is light and small and has a large load.
[0025]
[Embodiment of shell type roller bearing used for cam follower]
4 to 6 show an embodiment of a shell roller bearing used for the cam follower of the present invention. Here, a full-roller open needle needle roller bearing is illustrated as an example. FIG. 4 is a cross-sectional view of a half part of the shell-type needle roller bearing, FIG. 5 is an explanatory view showing a manufacturing process of the outer ring of the bearing of FIG. 4, and FIG. 6 is another manufacturing process of the outer ring of the bearing of FIG. FIG.
[0026]
In FIG. 4, reference numeral 20 indicates the entirety of a shell-shaped needle roller bearing used for a cam follower, 21 is a shell-shaped outer ring, and 22 is a needle roller. The shell-shaped outer ring 21 is manufactured from a single metal plate (thin steel plate) by a bending process including a bending process, and includes a cylindrical portion 21a having a raceway surface on an inner periphery, and both ends in the axial direction of the cylindrical portion 21a. Have flange portions 21b and 21c extending toward the inner diameter side, respectively. Of the two flanges 21b and 21c, the one at the axial end (the left end in the figure) is the flange 21b on the front bending side, and the thin one at the other end in the axial direction is the flange 21c on the rear bending side. A large number of the needle rollers 22 are arranged on the inner peripheral side of the outer ring 21 without a retainer.
[0027]
Each portion 21a of the outer ring 21, 21b, of 21c, the cylindrical portion 21a is highest thickness is thick, its thickness T ₁ is sufficiently withstand value for the radial load that is expected to be applied from the cam on the outer peripheral surface of the outer ring 21 Is set. Then, the plate thickness _{T 2} of the previous bending side of the flange portion 21b is thinner than the thickness _{T 1} of the cylindrical portion 21a, the thickness _{T 3} of the rear bending side of the flange portion 21c is a plate of the previous bending side of the flange portion 21b is thinner than the thickness _{T 2 (i.e., T 1> T 2> T} 3).
[0028]
According to the above configuration, among the portions 21a, 21b, and 21c of the outer race 21, the cylindrical portion 21a is the thickest, and therefore has sufficient strength to withstand an impact load applied directly from the cam.
[0029]
Further, the thickness T ₂ of the conventional prior bending side of the flange portion 21b which is the most thick in the outer ring of this type of bearing, the drawn cup needle roller bearing of this embodiment, the thinner than the cylindrical portion 21a Since the flange portion 21b is thin, the length of the needle roller 22 can be increased, and the width of the transfer surface of the needle roller 22 increases, and the rated load increases.
[0030]
Furthermore, since the flange 21b on the front bend side is thin, the curvature of the connecting portion between the flange 21b and the cylindrical portion 21a is reduced, and the inner surface of the connecting portion is connected to the end of the needle roller 22. From this point, it is possible to increase the length of the needle roller 22 to increase the width of the transfer surface, thereby increasing the rated load.
[0031]
If the length of the needle roller 22 is fixed, the total width of the bearing is reduced by the thinner flange portion 21b on the front bending side, so that compactness can be achieved.
[0032]
As described above, since the shell-shaped needle roller bearing 20 of the present embodiment secures a sufficient plate thickness in the cylindrical portion 21a of the outer ring 21, the shell-shaped needle roller bearing 20 receives a load applied directly from the cam to the outer peripheral surface of the outer ring 2. Since the load is large because the transfer surface of the needle roller 22 is wide on the inner peripheral side, the load is large. Therefore, it is difficult to use as a bearing for rotating the outer ring or as a rotating body with which the cam directly contacts the cam follower. Can be used without.
[0033]
Next, a process of manufacturing the shell-shaped outer race 21 will be described with reference to FIGS. This manufacturing process is not significantly different from the conventional manufacturing process of this type of shell-shaped outer ring, and a part of the manufacturing process includes a step of reducing the thickness of the flange portion 21a on the front bending side. There is a feature in the point.
[0034]
(A) In the first step, as a material of a single steel sheet of the required size, is subjected to bending in this, as shown in FIG. 5 (A), the element body 21 of the shallow cup-shaped bottomless ₀ Is molded. Here, the whole has a substantially uniform plate thickness.
[0035]
(B) body in the second step, the relative bottom of the element body 21 ₀ of the bowl-shaped, performs a thinning process by the press, the bottom portion as shown in FIG. 5 (B) becomes thin make a 21 _1. Here, the reason why the thick portion is left around the bottom portion is to prevent the thickness of the connection portion between the bottom portion and the tubular portion from becoming excessively thin in subsequent processing.
[0036]
(C) In the third step, by drawing, the bottom from the element body 21 ₁ is thinner, making bottom deep bottomed cylindrical member 21 _2, as shown in (C) of FIG. In the bottom of the cylindrical body 21 _2, the thickness of the bottom portion is made thinner than the thickness of the cylindrical portion.
[0037]
(D) In the fourth step, the portion of the rear bent end of the flange portion 21c is formed, i.e., the cylindrical body 21 _{and second} opening portions of the bottom is trimmed, as shown in (D) in FIG. 5, the opening part is the cylindrical body 21 ₃ it became thin obtained.
[0038]
(E) In the fifth step, the opening is subjected to drilling to the bottom of the cylindrical body 21 ₃ became thin. This, as shown in (E) of FIG. 5, the cylindrical body 21 ₄ with a hole obtained on the bottom. The bottom with the hole becomes the flange 21b on the first bending side.
[0039]
(F) In the sixth step, the fifth bending the opening of the resulting tubular body 21 ₄ thin is subjected in step, as shown in (F) in FIG. 5, the rear bent end of the flange part 21c is formed, after almost completed form 21 ₅ next to the outer ring 21, this, this is made heat treatment, the outer ring 21 shown is completed in FIG.
[0040]
In the above fabrication process, only subjected to thinning processing at the bottom of the element body 21 ₀ of bowl-shaped, cylindrical portion 21a is thick, since the outer ring 21 previously bent side of the flange portion 21b is thin is obtained, Most of the conventional outer ring manufacturing process can be used, and the required outer ring 21 can be manufactured relatively easily.
[0041]
The shell-shaped outer ring 21 can be manufactured by other manufacturing processes. FIG. 6 shows another manufacturing process of the outer race 21. The other manufacturing process will be described with reference to FIGS.
[0042]
(A) In the first step, as a material of a single steel sheet of the required size, by now bending, molding the body 31 ₀ shallow bowl shaped with a bottom as shown in FIG. 6 (A) .
[0043]
(B) In the second step, stop the process, the element body 31 ₀ of the bowl-shaped, making bottom deep bottomed cylindrical body 54 _1, as shown in FIG. 6 (B). At this stage, the thickness of the tubular body 31 ₁ at the bottom of the bottomed are thicker than the plate thickness of the cylindrical portion.
[0044]
(C) In the third step, part of the rear bent end of the flange portion 21c is formed, i.e., the cylindrical body 31 ₁ of the opening of the bottomed be trimmed, as shown in (C) of FIG. 6, the opening part is the cylindrical body 31 ₂ became thinner is obtained.
[0045]
(D) In the fourth step, openings are subjected to drilling in the bottom of the cylinder 31 ₂ became thin. This, as shown in (D) of FIG. 6, the cylindrical body ₃₁₃ there is a hole obtained on the bottom. At this stage, the thickness of the bottom of the cylindrical body ₃₁₃ having a bottom is still thick than the plate thickness of the cylindrical portion.
[0046]
(E) In the fifth step, to the bottom of the cylindrical body ₃₁₃ with a bottom was morning perforated performs thinning processing by pressing, cutting the protruding portion on the inner diameter side of the bottom portion by the press. This, as shown in (E) of FIG. 6, the tubular body 31 ₄ bottom has become thin where there is a hole is obtained. The thin and perforated bottom part becomes the flange part 21b on the front bending side.
[0047]
(F) In the following sixth step, the processing is subjected bent into the opening of the resulting tubular body 31 ₄ thin in the fifth step, as shown in (F) in FIG. 6, the rear bending side the flange portion 21c is formed in the finished form 31 ₅ next to almost the outer ring 21, Thereafter, this is made heat treatment, the outer ring 21 shown in FIG. 1 is completed.
[0048]
In the above-described embodiment, the full-roller type open needle-shaped needle roller bearing has been described, but the shell-type needle roller bearing used for the cam follower of the present invention is an outer ring having flanges at both axial ends of a cylindrical portion. As long as the bearing is provided, a shell-shaped needle roller bearing with a retainer may be used. The rollers arranged on the inner periphery of the shell-shaped outer ring 11 are not limited to the needle rollers 12, but may be cylindrical rollers.
[0049]
Further, a plurality of oil retaining grooves may be formed on the outer peripheral surface of the shell-shaped outer race 11 along the axial direction or along a direction intersecting at an acute angle with the axial direction. With such an oil retaining groove, an oil film is formed over a wide area of the outer peripheral surface of the outer ring 11 or over the entire outer peripheral surface, thereby preventing excessive wear caused by the contact of the cam 2. Can be. The outer peripheral surface of the shell-shaped outer race 11 may be crowned. With this crowning, it is possible to prevent damage such as wear due to excessive edge load caused by the contact of the cam 2.
[0050]
As shown in FIG. 5 or FIG. 6, the shell-shaped outer ring 21 is manufactured from a single metal plate by a processing process including a bending process, and is also manufactured by another processing process, for example, using a metal pipe as a raw material. It may be.
[0051]
In addition, in the shell-shaped needle roller bearing used for the cam follower of the present invention, one of the flanges of the outer ring (the flange on the bending side) extends to the axial center position to seal one axial end of the bearing. A so-called one-end sealed shell needle roller bearing may be used. The above-mentioned one-end closed type needle-shaped needle roller bearing has a cantilevered shaft which is in contact with a cam like a stud type cam follower by inserting a cantilevered shaft serving as an inner ring into an inner diameter portion thereof. The cam follower is supported by.
[0052]
In addition, the shell-type roller bearing used for the cam follower of the present invention can be used as an outer ring rotation bearing other than the cam follower.
[0053]
【The invention's effect】
In the cam follower of the present invention, during assembly, the rollers are held inside the outer ring so as not to come off by the flanges and grease of the outer ring. The assembly work can be performed easily and efficiently without increasing the cost. Further, by using a shell type roller bearing having a large rated load in a small space, it is possible to reduce the weight and size without reducing the load applied to the cam follower.
[0054]
Shell type roller bearing used in the cam follower of the present invention, if the thickness of the cylindrical portion of the outer ring is thicker than the thickness of any flange portion, sufficient plate thickness is ensured in the cylindrical portion of the outer ring, On the inner circumference side, the length of the rollers can be lengthened and the width of the roller transfer surface can be increased, so that it has a large strength against loads applied directly from the outside to the outer circumference of the outer ring, and has a large rated load. It can also be used in places where an impact load is applied, and can be used without trouble as a rotating body on which a cam directly contacts in a cam follower, which is useful for obtaining a lightweight, compact, and large load load cam follower.
[Brief description of the drawings]
FIG. 1 is a vertical sectional side view of a rocker arm according to an embodiment of the present invention.
FIG. 2 is a plan view of the rocker arm of FIG. 1;
FIG. 3 is a sectional view taken along line (3)-(3) in FIG.
FIG. 4 is a sectional view of a half part of a shell needle roller bearing used for the cam follower of the present invention.
FIG. 5 is an explanatory view showing a manufacturing process of an outer ring of the bearing of FIG. 4;
FIG. 6 is an explanatory view showing another manufacturing process of the outer ring of the bearing of FIG. 4;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Rocker arm 5 Side wall 6 Side wall 10 Support shaft 11 Outer ring 11b, 11c Collar part 12 Needle roller 13 Shell type needle roller bearing 20 Shell type needle roller bearing 21 Shell type outer ring 21a Cylindrical part 21b, 21c Collar part 22 Needle shape Roller

Claims (4)

A pair of side walls facing each other at an interval, and a spindle provided between the side walls,
On the outer periphery of the support shaft, a shell-shaped roller including a shell-shaped outer ring having flange portions extending to the inner diameter side at both axial ends of the cylindrical portion, and a plurality of rollers disposed on the inner circumference side of the outer ring. A cam follower provided with a bearing. 2. The cam follower according to claim 1, wherein the shell-type roller bearing is a full-roller type in which a plurality of rollers are arranged on an inner peripheral side of an outer ring without passing through a retainer. 3. The cam follower according to claim 1, wherein a thickness of the cylindrical portion of the outer ring in the shell roller bearing is greater than a thickness of any of the flange portions. 4. The outer ring is manufactured by a processing step including bending from a single metal plate, and of the two flange portions of the outer ring, the thickness of the flange portion on the front bending side is greater than the thickness of the cylindrical portion. 4. The cam follower according to claim 3, wherein the thickness of the flange portion on the rear bending side is thinner than the thickness of the flange portion on the front bending side. 5.

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