JP4314459B2 - Resin pulley and resin pulley with rolling bearing - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pulley integrally formed using a resin, and more particularly to a resin pulley and a resin pulley with a rolling bearing that have a high heat dissipation effect and good roundness of a belt rolling surface.
[0002]
[Prior art]
The camshaft and auxiliary machinery of the vehicle engine are rotationally driven by power transmission by an endless belt. In such a power transmission mechanism using an endless belt, a resin idler pulley, a guide pulley, or a tension is attached to a part of the endless belt that is detached from the driving pulley connected to the crankshaft or the driven pulley connected to the auxiliary machinery. A pulley or the like is provided, and an endless belt is stretched over them to maintain the winding angle and to apply tension to the driving pulley and the driven pulley.
[0003]
FIG. 4 is a front view of a conventional resin pulley as viewed from the axial direction, and FIG. 5 is a cross-sectional view taken along the line AA in FIG.
As shown in FIG. 4, the resin pulley includes a concentric outer cylindrical portion 1, an inner cylindrical portion 2, and an annular disc that integrally connects the outer cylindrical portion 1 and the inner cylindrical portion 2. It is formed mainly of the part 3. A plurality of radial reinforcing ribs 5, 5,... For connecting the outer cylindrical portion 1 and the inner cylindrical portion 2 along the radial direction of the pulley are formed on both end faces of the annular disc portion 3. ing. In addition, on the inner periphery of the inner cylindrical portion (boss portion) 2 of the resin pulley, a rolling bearing or the like that rotatably supports the pulley is disposed, and on the outer peripheral surface 1x of the outer cylindrical portion 1, An endless belt or the like (not shown) is stretched over.
[0004]
As shown in the partial cross-sectional view of FIG. 5, the outer cylindrical portion 1 having the belt rolling surface (outer peripheral surface 1x) is formed wider than the inner cylindrical portion 2, and is spaced apart in the radial direction. The annular disc portion 3 disposed between the outer cylindrical portion 1 and the inner cylindrical portion 2 is formed from the axial center of the outer cylindrical portion 1 to the axial center of the inner cylindrical portion 2. Further, the reinforcing ribs 5, 5 arranged on the end surface of the annular disk portion 3 are formed between the end portions of the inner peripheral surface 1 y of the outer cylindrical portion 1 and the outer peripheral surface 1 x of the inner cylindrical portion 2. The reinforcing rib 5 on the side of the end surface 3a and the reinforcing rib 5 on the side of the other end surface 3b are formed so as to be paired at positions that have the same phase in the circumferential direction.
[0005]
As a material for the resin pulley having the above-described configuration, for example, a material using polyamide resin blended with reinforcing fibers such as glass fiber is adopted, and like the pulley in this example, the outer ring outer periphery of the rolling bearing is used. Many are integrally formed by injection molding on the surface.
[0006]
It is known that resin pulleys shrink after molding, but the outer cylindrical part, which is larger in diameter and thinner than the inner cylindrical part, is supported by a part (supporting part) supported by a reinforcing rib. The shrinkage rate is different from that of the non-supported part (non-supported part), and the roundness may be deteriorated by cooling after molding. For this reason, various proposals and ideas have been made regarding the shape and arrangement of the reinforcing ribs arranged on the annular disk portion in order to alleviate the circumferential shrinkage difference in the outer cylindrical portion (for example, Patent Document 1). And Patent Document 2).
[0007]
[Patent Document 1]
Japanese Utility Model Publication No. 4-106551 [Patent Document 2]
JP 2001-90811 A
[Problems to be solved by the invention]
By the way, in the above resin pulleys and resin pulleys with rolling bearings, since they are formed using synthetic resin as a material, there is a problem that heat dissipation is worse than that of metal pulleys.
[0009]
When the resin pulley becomes high temperature due to heat storage, this heat has various adverse effects on the rotation of the pulley. For example, in a resin pulley having a conventional radial reinforcing rib, the rigidity of the outer cylindrical portion of the pulley differs between a portion supported by the reinforcing rib (supporting portion) and a portion not supported (non-supporting portion). It is known that the load from the belt is concentrated at the connection point between these reinforcing ribs and the inner cylindrical portion (boss portion). In addition, since a difference in thermal expansion coefficient occurs between the support part and the non-support part due to the presence or absence of the reinforcing rib, the roundness of the outer peripheral surface (belt rolling surface) of the outer cylindrical portion is increased by the temperature increase due to heat storage. In some cases, the above-described load concentration becomes more remarkable.
[0010]
Further, in the case of a resin pulley in which a rolling bearing is arranged on the inner periphery of the inner cylindrical portion, the temperature of the grease enclosed in the bearing rises due to heat storage, and this grease is accelerated. Furthermore, when the circumferential deviation of the load occurs due to the deterioration of the roundness of the belt rolling surface as described above, the outer ring raceway inside the bearing is deformed, and the pulley vibration or the bearing Troubles such as abnormal noise or reduced bearing life may occur.
[0011]
The present invention has been made to cope with the above-described problems, and is a resin pulley and a resin pulley with a rolling bearing that can suppress the temperature rise of the pulley while maintaining the roundness of the belt rolling surface. The purpose is to provide.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, an invention according to claim 1 is directed to an outer cylindrical portion and an inner cylindrical portion that are provided concentrically with each other, and an annular disc portion that connects the outer cylindrical portion and the inner cylindrical portion. And a plurality of reinforcing ribs respectively disposed on both end faces of the annular disk portion, wherein the reinforcing rib is connected only to the outer cylindrical portion. A first reinforcing rib formed in a shape extending toward the inner cylindrical portion, and a second reinforcing rib formed in a shape connected only to the inner cylindrical portion and extending toward the outer cylindrical portion. The first and second reinforcing ribs and the second reinforcing rib are disposed on each end face of the annular disk portion as a portion for reinforcing the annular disk portion. The reinforcing rib is the circumferential direction of the pulley end face Alternately along, and formed in a shape that are separated independently from each other, further, said these first reinforcing ribs second reinforcing ribs, the same band-like region of the tip each other is of the pulley circumferential direction to each other of the pulley radial The tip of one reinforcing rib is formed to have a length exceeding the radial position of the tip of the other reinforcing rib adjacent in the circumferential direction.
[0013]
The invention according to claim 2 is a resin pulley with a rolling bearing, characterized in that a rolling bearing is disposed on the inner periphery of the inner cylindrical portion of the resin pulley according to claim 1. It is characterized by that.
[0014]
In the resin pulley having the reinforcing rib on the end face of the annular disk portion, in order to improve the heat dissipation of the resin pulley, it is important how to increase the surface area of the pulley side surface. However, as an aid to the conventional concept of reinforcing ribs in resin pulleys, the increase in the number of radial reinforcing ribs connected from the outer cylindrical portion to the inner cylindrical portion can alleviate the circumferential rigidity difference of the outer cylindrical portion. Therefore, there is a possibility that sufficient roundness of the belt rolling surface cannot be secured. Accordingly, the present invention forms a large number of reinforcing ribs that are staggered in the circumferential direction between the outer cylindrical portion and the inner cylindrical portion as means for enhancing the heat dissipation effect of the pulley while ensuring the roundness of the outer cylindrical portion. And the method of utilizing these as a radiation fin is employ | adopted.
[0015]
That is, according to the first and second aspects of the invention, each of the reinforcing ribs is connected to only one of the outer cylindrical portion and the inner cylindrical portion, and is formed in a shape extending toward the other cylindrical portion. By doing so, sufficient roundness of the outer peripheral surface of the outer cylindrical portion serving as the belt rolling surface can be ensured. In other words, by forming these reinforcing ribs in a shape that does not continue from one cylindrical part to the other cylindrical part, these reinforcing ribs do not stretch in the radial direction, and the rigidity difference in the circumferential direction of the outer cylindrical part is reduced. can do.
[0016]
Further, by arranging the reinforcing ribs extending from the outer cylindrical part toward the inner cylindrical part and the reinforcing ribs extending from the inner cylindrical part toward the outer cylindrical part alternately in the circumferential direction, the outer cylindrical part is arranged. The number of reinforcing ribs can be increased without increasing the rigidity difference in the circumferential direction of the portion. In addition, the surface area of the pulley side surface can be increased at the same time as the number of reinforcing ribs is increased. Therefore, the resin pulley of the present invention and the resin pulley with a rolling bearing can enhance the heat dissipation effect of the pulley without deteriorating the roundness of the outer cylindrical portion.
[0017]
In the present invention, the number of reinforcing ribs provided on both end faces of the annular disk portion is not particularly limited, but in order to increase the heat dissipation effect and strength of this pulley, as much reinforcement as possible in the circumferential direction is provided. It is advantageous to provide ribs. These reinforcing ribs, rather preferably be equally spaced circumferentially alternately, furthermore, in order to secure the length of the first reinforcing rib and the pulley diameter direction of the second reinforcing ribs, these Reinforcing ribs may be extended in the pulley radial direction so that the tip ends in the radial direction are alternately arranged in the same belt-like region in the circumferential direction of the pulley.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of a resin pulley according to an embodiment of the present invention viewed from the axial direction. In addition, the same code | symbol is attached | subjected to the structural member which has the same function as a prior art example.
[0019]
Similarly to the conventional example, this resin pulley also includes an outer cylindrical portion 1 arranged in a concentric manner, an inner cylindrical portion 2, and an annular disc portion 3 that integrally connects the outer cylindrical portion 1 and the inner cylindrical portion 2. The main body is formed. A plurality of linear reinforcing ribs 4a and 4b are formed on both end faces of the annular disk portion 3 to connect the outer cylindrical portion 1 and the inner cylindrical portion 2 along the radial direction of the pulley. In addition, a rolling bearing similar to the conventional example is disposed on the inner periphery of the inner cylindrical portion (boss portion) 2 of the resin pulley, and the outer peripheral surface 1x of the outer cylindrical portion 1 is endless (not shown). A belt or the like is stretched over.
[0020]
The synthetic resin material constituting the resin pulley is not particularly limited. For example, polyamide 6 resin, polyamide 6-6 resin, phenol resin, or polyacetal resin can be used. Moreover, you may mix reinforcing fibers, such as glass fiber, with these synthetic resins as needed.
[0021]
The resin pulley according to the present embodiment is characterized in that the first reinforcing rib 4a and the first reinforcing rib 4a are connected to only one of the cylindrical portions and extend linearly along the radial direction of the pulley toward the other cylindrical portion. A large number of two reinforcing ribs 4b are formed on the end face of the annular disc portion 3, the first reinforcing rib 4a extending from the outer cylindrical portion 1 toward the inner cylindrical portion 2, and the outer cylindrical portion from the inner cylindrical portion 2. The second reinforcing ribs 4b extending toward 1 are alternately arranged at equal intervals along the circumferential direction so as to be staggered in the circumferential direction.
[0022]
With the above-described reinforcement rib configuration, the resin pulley has a surface area on the side of the pulley that is significantly increased compared to conventional resin pulleys, and the rotation of the pulley causes the numerous reinforcement ribs 4a and 4b to function as heat radiation fins. Become functional. Therefore, the resin pulley according to the present embodiment has not only a high heat dissipation effect of the pulley itself but also an effect of cooling the rolling bearing disposed on the inner periphery.
[0023]
In addition, the resin pulley has a small difference in rigidity between a portion (supported portion) supported by the first reinforcing rib 4a in the outer cylindrical portion 1 and a portion not supported (non-supported portion). That is, with this reinforcing rib configuration, the difference in the shrinkage rate in the circumferential direction after forming the pulley and the difference in the thermal expansion rate in the circumferential direction when the temperature of the pulley rises can be alleviated at the same time. Therefore, the resin pulley according to the present embodiment can maintain a sufficient roundness of the outer peripheral surface 1x of the outer cylindrical portion serving as a belt rolling surface without being influenced by the pulley temperature.
[0024]
Furthermore, the pulley can support the pulley by dispersing the stress in the circumferential direction without concentrating the load from the belt on the connection point between the second reinforcing rib 4 b and the inner cylindrical portion 2. Therefore, the resin pulley in the present embodiment also has the effect of preventing the occurrence of vibration and abnormal noise during rotation without causing local deformation of the outer ring raceway of the rolling bearing arranged on the inner periphery. Can play.
[0025]
In the present embodiment, the shape of the first reinforcing rib 4a and the second reinforcing rib 4b formed on the end face of the annular disc portion 3 is a linear shape extending substantially along the radial direction of the pulley. The shape of the reinforcing rib in the present invention is not limited to this, and any shape may be used as long as they are not connected in the radial direction so as not to increase the difference in rigidity in the circumferential direction. For example, as shown in FIG. 2, a protruding portion in the circumferential direction is provided at the tip of the first reinforcing rib 4c and the second reinforcing rib 4d in order to further increase the surface area, or the first reinforcing rib as shown in FIG. 4e may be formed by bending the second reinforcing rib 4f in the middle. Further, in order to further reduce the difference in rigidity in the circumferential direction of the outer cylindrical portion, the reinforcing rib on one end surface side and the reinforcing rib on the other end surface side of the annular disc portion 3 have different phases in the circumferential direction. You may form as follows.
[0026]
【The invention's effect】
As described above in detail, according to the configuration of the reinforcing rib of the present invention, it is possible to achieve both relaxation of the rigidity difference in the circumferential direction of the outer cylindrical portion and expansion of the surface area of the pulley side surface. Therefore, the resin pulley and the resin pulley with a rolling bearing can enhance the heat dissipation effect while ensuring sufficient roundness of the outer peripheral surface of the outer cylindrical portion serving as the belt rolling surface. Trouble can be prevented.
[Brief description of the drawings]
FIG. 1 is a front view of a resin pulley according to an embodiment of the present invention viewed from an axial direction.
FIG. 2 is a front view showing another reinforcing rib configuration in the resin pulley according to the embodiment of the present invention.
FIG. 3 is a front view showing still another reinforcing rib configuration in the resin pulley according to the embodiment of the present invention.
FIG. 4 is a front view of a conventional resin pulley as viewed from the axial direction.
FIG. 5 is a partial cross-sectional view showing a reinforcing rib configuration in a conventional resin pulley.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Outer cylindrical part 1x Outer peripheral surface 1y Inner peripheral surface 2 Inner cylindrical part 2x Outer peripheral surface 2y Inner peripheral surface 3 Annular disk part 3a, 3b End surface 4a First reinforcing rib, 4b Second reinforcing rib 4c First reinforcing rib, 4d First Two reinforcing ribs 4e First reinforcing rib, 4f Second reinforcing rib 5 Reinforcing rib

Claims (2)

An outer cylindrical portion and an inner cylindrical portion provided concentrically with each other, an annular disc portion connecting the outer cylindrical portion and the inner cylindrical portion, and a plurality of reinforcements respectively disposed on both end faces of the annular disc portion In the resin pulley formed by integrally molding the rib with resin,
The reinforcing rib is connected only to the outer cylindrical portion and is formed in a shape extending toward the inner cylindrical portion, and is connected only to the inner cylindrical portion and extends toward the outer cylindrical portion. The first reinforcing rib and the second reinforcing rib are disposed on each end face of the annular disc portion as a portion for reinforcing the annular disc portion. And
Said first reinforcing rib and the second reinforcing rib is, alternately along the circumferential direction of the pulley end surface, and is formed in a shape spaced independent of each other, further, with these first reinforcing rib and the second reinforcing rib The tip of one reinforcing rib exceeds the radial position of the tip of the other reinforcing rib adjacent in the circumferential direction so that the tip ends in the pulley radial direction are alternately arranged in the same belt-like region in the pulley circumferential direction. A resin pulley having a length . A resin pulley with a rolling bearing, wherein a rolling bearing is disposed on the inner periphery of the inner cylindrical portion of the resin pulley according to claim 1.

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