This application is based on and claims priority under 35 U.S.C. ยง119 to Japanese Patent Application 2007-237021, filed on Sep. 12, 2007, the entire contents of which is incorporated herein by reference.
The present invention relates to a lubricating oil supply device for supplying lubricating oil to an inside of a rotational shaft.
Conventionally, lubricating oil is supplied to an inside of a rotational shaft such as an input shaft, a counter shaft, an output shaft and the like of a transmission apparatus from an end portion or from an outer circumference of the rotational shaft. In a case where other components are provided at both end portions of the rotational shaft, the lubricating oil may not be able to be supplied to the inside of the rotational shaft from the end portion thereof, and the lubricating oil needs to be supplied to the inside of the rotational shaft from the outer circumference thereof.
An intermediate portion 3a of the output shaft 3 is rotatably fitted into an inner hole 2a of a boss portion 2 formed at the transmission housing 1. A center bore 3c, having a smaller diameter than a diameter of the bearing hole 3d, is coaxially formed at the output shaft 3 so as to continuously extend from the bearing hole 3d in an axial direction of the output shaft 3. An annular groove 3b is formed at an outer circumference of the intermediate portion 3a of the output shaft 3. The annular groove 3b spatially extends to the center bore 3c via a fluid communication bore 3e for establishing a flow of the lubricating oil therebetween. A guide passage is formed at an upper portion of a base portion of the boss portion so as to extend orthogonally to the axial direction of the output shaft 3 for establishing the connection between space of an inside of the transmission housing 1 and the annular groove 3b. Seal materials 5a are provided within seal grooves 5 formed at the outer circumference of the intermediate portion 3a of the output shaft 3 at positions corresponding to both sides of the annular groove 3b in the axial direction of the output shaft 3.
In the conventional lubricating oil supply device, the lubricating oil spattered within the transmission housing 1 lubricates the bearing 7a supporting the end portion of the input shaft 7 at the inner end portion of the output shaft 3 by guiding the spattered lubricating oil to the annular groove 3b through a guide passage 2b and to the center bore 3c via the fluid communication bore 3e.
However in the lubricating oil device having the above-described configuration, centrifugal force is applied to the lubricating oil contained within the rotating output shaft 3, which results in preventing the lubricating oil, guided from the guide passage 2b, from entering the center bore 3c through the fluid communication bore 3e. Specifically when the output shaft 3 is rotated at high-speed, the centrifugal force is increased, thereby decreasing a supply of the lubricating oil to a portion to be lubricated (hereinafter referred to as a lubrication necessitating portion) such as the bearing 7a and the like. As a result, the lubrication necessitating portion may not be sufficiently lubricated. In order to eliminate the drawback mentioned above, an oil pump may be separately provided at the lubricating oil supply device to pressurize the lubricating oil and supply the pressurized lubricating oil to the guide passage 2b. However, providing the oil pump may increase manufacturing costs of the lubricating oil supply device.
A need thus exists to provide a lubricating oil supply device which is not susceptible to the drawback mentioned above.
According to an aspect of the present invention, a lubricating oil supply device includes a casing, a rotational shaft rotatably supported by the casing, a center bore formed at the rotational shaft, an accommodating groove formed at an outer circumference of an intermediate portion of the rotational shaft in an annular-shape, a cylindrical bore coaxially formed in the casing relative to the rotational shaft, the cylindrical bore formed in the casing at a position corresponding to the intermediate portion of the rotational shaft, a guide passage radially extending through a portion of the casing so that one end of the guide passage opens to an inside of the casing and the other end of the guide passage opens to a portion of the cylindrical bore, a discharge passage formed at the rotational shaft at a position corresponding to a position where the guide passage is formed, one end of the discharge passage opening to a bottom surface of the accommodating groove and the other end of the discharge passage opening to the center bore of the rotational shaft, and a lubricating oil guiding member accommodated within the accommodating groove and including a cylindrical portion, which extends in a circumferential direction, the lubricating oil guiding member rotated with the rotational shaft so as to slidably contact the cylindrical bore at an outer circumferential surface of the cylinder portion, wherein the lubricating oil guiding member further includes a guide hole, which has a first inner side surface and a second inner side surface facing each other in the circumferential direction of the lubricating oil guiding member, so that the guide hole is always connected to the discharge passage to establish the fluid communication therebetween, the first inner side surface is connected to an outer circumferential surface of the cylindrical portion so as to form an angle therebetween, and the lubricating oil guiding member further includes a guide groove extending along the outer circumferential surface of the lubricating oil guiding member and ending at an end surface formed at the lubricating oil guiding member at a position away from the first inner side surface, the guide groove is connected to the guide hole at a portion where the second inner side surface is formed so as to establish the fluid communication therebetween.
The foregoing and additional features and characteristics of the present invention will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein:
An embodiment of a lubricating oil supply device for supplying lubricating oil to an inside of a rotational shaft of, for example, a transmission apparatus will be described below in accordance with
As illustrated in
The input shaft 7, coaxially arranged relative to the output shaft 15, and the end portion of the input shaft 7 is rotatably supported at the bearing hole 17b, formed at the inner end portion of the output shaft 15 via the needle roller bearing 7a. A plural pairs of shift gear sets are provided between the input shaft 7 and a counter shaft (not shown), arranged in parallel to the input shaft 7 and the output shaft 15. In
The portion of the output shaft 15 at the right side than the reduction driven gear 16 in
As illustrated in
The lubricating oil guiding member 20 is integrally formed with a pair of cylindrical portions 21, to which a pair of annular protrusions 25 are integrally formed respectively, so as to maintain substantially the same distance as a distance between the annular grooves 18a in the lateral direction. An entire width of the lubricating oil guiding member 20 in the axial direction of the output shaft 15 is formed to be narrower than a width of the accommodating groove 18 in the axial direction of the output shaft 15. Further, the pair of cylindrical portions 21 has cross-sections whose heights are substantially the same as a height of the accommodating groove 18 in the direction orthogonal to the axial direction of the output shaft 15. Each of the pair of annular protruding portions 25 is formed to have slightly narrower width than a width of each of the annular groove 18a and to have substantially the same height as a height of each of the annular groove 18a in the direction orthogonal to the axial direction of the output shaft 15. The pair of the annular protruding portions 25 extends inwardly towards the output shaft 15. Further, a pair of guide holes 22 is formed at the lubricating oil guiding member 20 at positions between the annular protruding portions 25 so that the pair of the guide holes 22 substantially oppose to each other in the diametrical direction of the lubricating oil guiding member 20. Each of the guide holes 22 is formed to have a cross-section in a quadrilateral shape in a circumferential direction of the cylindrical portion 21. Further, each of the guide holes 22 includes a forward inner side surface 22a (a first inner side surface) and a rearward inner side surface 22b (a second inner side surface), both of which are formed in flat surface-shapes and which face each other in the circumferential direction of the cylindrical portion 21. The forward inner side surface 22a and the rearward inner side surface 22b are outwardly extended from an inner circumferential surface 21b of each of the cylindrical portion 21 in the radial direction of the lubricating oil guiding member 20. The forward inner side surfaces 22a are surfaces that are moved in a direction towards a side where the guide holes 22a are formed, in a case where the lubricating oil guiding member 20 is rotated in a positive direction (a direction indicated by an arrow R in
A pair of guide grooves 23 (a guide groove 23) is formed so as to extend along an outer circumferential surface of the lubricating oil guiding member 20 at a position between the pair of cylindrical portions 21. Each of the guide grooves 23 has a width substantially the same as a width of the guiding holes 22 in the axial direction of the output shaft 15. One end of each of the guide grooves 23 is connected to the corresponding guide groove 22 and the other end of each of the guide grooves 23 ends at corresponding end surface 23a that is integrally formed at the outer circumferential surface 21a of the cylindrical portion 21 so as to be positioned opposite from the corresponding forward inner side surface 22a in a circumferential direction of the cylindrical portion 21. As mainly illustrated in
The above-descried lubricating oil guiding member 20 is integrally formed by synthetic resin, having abrasion resistance and elasticity, such as polyacetal resin, polyamide resin and the like, so that a diameter of the cylindrical portion 21 is formed to be slightly larger than a diameter of the cylindrical bore 12. The lubricating oil guiding member 20 is assembled within the accommodating groove 18 so as to be rotated together with the output shaft 15 (rotational shaft) in a manner where: firstly, inserting the third step portion of the output shaft 15, at which only the first tapered roller bearing 19a is attached, through inside the lubricating oil guiding member 20; secondly, outwardly enlarging the cylindrical portion 21 and the annular protrusions 25 by the elasticity of the synthetic resin by applying a force to the lubricating oil guiding member 20 so as to open the cut 20a; thirdly, moving the lubricating oil guiding member 20 towards the input shaft 7 (to the left in
In the above-described embodiment, as the input shaft 7 is rotated relative to the output shaft 15, the needle roller bearing 7a needs to be lubricated, except for a case where the input shaft 7 and the output shaft 15 are directly connected by means of the synchromesh mechanism 9. In this embodiment, in a case where a vehicle is used in a normal condition, i.e. in a case where the vehicle moves forward, the output shaft 15 is rotated in the positive direction (the direction indicated with the arrow R in
As illustrated mainly in
In the above-described embodiment, the lubricating oil guiding member 20 is made of the synthetic resin having the abrasion resistance and the elasticity. Further, the lubricating oil guiding member 20 is formed in the C-shape by providing the cut 20a at one portion thereof so as to extend in the axial direction of the output shaft 15. The outer circumferential surface 21 a elastically contacts the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15. Further, the lubricating oil guiding member 20 is arranged within the accommodating groove 18 so that the cut 20a is positioned at one of the guide holes 22 and so that one end surface of the cut 20a is inclined so as to correspond to the inclination of one of the forward inner side surface 22a. Accordingly, the forward inner side surfaces 22a, which are provided so as to be integrally connected to the outer circumferential surface 21a of the lubricating oil guiding member 20, specifically which is provided at the most outer circumferential portion of the lubricating oil guiding member 20 in the radial direction thereof, for changing the moving direction of the lubricating oil inwardly, contact the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15. As a result, the lubricating oil is supplied within the center bore 17 through the discharge passages 17a by changing the moving direction of the lubricating oil inwardly towards the center bore 17 while restricting an amount of leakage of the lubricating oil to be a minimum. However, the lubricating oil supply device of the present invention is not limited to the above-described structure, for example, the cut 20a of the lubricating oil guiding member 20 may be provided at any desired positioned, other than the position corresponding to the guide hole 22, at any desired angle. In a case where the cut 20a of the lubricating oil guiding member 20 is provided at a position, other than the position corresponding to the guide hole 22, by forming an angle, the outer circumferential surface 21a also elastically contacts the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15, therefore the outer circumferential surface 21a and the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15 form very little clearance therebetween, thereby greatly reducing the amount of the lubricating oil, moving through the lubricating oil guiding member 20, leaking outside the lubricating oil guiding member 20.
Alternatively, the lubricating oil guiding member 20 may be made of a material having the abrasion resistance and the elasticity, and the lubricating oil guiding member 20 may be divided into two pieces in the diametrical direction thereof and assembled at the accommodating groove 18. In a case where the divided lubricating oil guiding member 20 is assembled at the accommodating groove 18, a contact between the lubricating oil guiding member 20 and the inner circumferential surface of the cylindrical bore 12, more specifically, the end casing portion 10b corresponding to the second step portion of the output shaft 15, is achieved by the centrifugal force. Therefore, although the lubricating oil guiding member 20 may not firmly contact the cylindrical bore 12, as is the case with the lubricating oil supply device of the above-described embodiment, the lubricating oil, guided to the guide holes 22 and the guide grooves 23 of the lubricating oil guiding member 20, is smoothly directed inwardly in the radial direction thereof by means of the forward inner side surfaces 22a. Then, the lubricating oil is guided to the center bore 17 through the discharge passages 17a so as to resist against the centrifugal force generated by the rotation of the output shaft 15, thereby lubricating the needle roller bearing 7a.
In the above-descried embodiment, the lubricating oil guiding member 20 is configured to be rotated together with the output shaft 15 by engaging the protrusions 24, formed at the inner circumferential surface of the lubricating oil guiding member 20, with the recessed portions 18b formed at the bottom surface of the accommodating grooves 18, respectively. In other words, the structure for simultaneously rotating the lubricating oil guiding member 20 and the output shaft 15 is achieved by the protrusions 24 formed at the inner circumferential surfaces of the lubricating oil guiding member 20 and the recessed portions 18b formed at the bottom surface of the accommodating groove 18, therefore, the structure for simultaneously rotating the lubricating oil guiding member 20 and the output shaft 15 is simplified. Further, the lubricating oil guiding member 20 is assembled relative to the accommodating groove 18 of the rotational shaft 15 in a simple manner where; the lubricating oil guiding member 20 is elastically enlarged in order to be accommodated within the accommodating groove 18 by opening the cut 20a, the positions of the protrusions 24 adjusted relative to the corresponding recessed portions 18b, then the lubricating oil guiding member 20 is restored to the substantially original shape by the elasticity thereof. In the above-descried embodiment, the protrusions 24 are formed at the lubricating oil guiding member 20, and the recessed portions 18b are formed at the rotational shaft 15. Alternatively, a protrusion 24 may be formed at the rotational shaft 15, and a recessed portion 18b may be formed at the lubricating oil guiding member 20. Further, in the above-described embodiment, the protrusions 24 are formed at the inner circumferential surface of the lubricating oil guiding member 20, and the recessed portions 18b are formed at the bottom surface of the accommodating groove 18 of the rotational shaft 15. Alternatively, as long as the protrusion 24 and the recessed portion 18b are structured to engage the lubricating oil guiding member 20 and the output shaft 15 and to rotate the lubricating oil guiding member 20 together with the output shaft 15, the protrusion 24 may be provided at a bottom circumferential surface of each annular protruding portion 25 of each cylindrical portion 21, facing the rotational shaft 15, and a recessed portion 18b may be formed at a bottom surface of each annular groove 18a of the accommodating groove 18.
In the above-described embodiment, the pair of annular protruding portions 25 are provided at the pair of cylindrical portions 21, respectively so that the protruding portions 25 are arranged at the positions corresponding to the both sides of the guide holes 22, formed at the inner circumferential surface of the lubricating oil guiding member 20 at the position between the pair of the cylindrical portions 21, in the axial direction of the rotational shaft 15. Further, the pair of annular grooves 18a for accommodating the corresponding annular protruding portions 25 is formed on the bottom surface of the accommodating groove 18. Accordingly, a contacting force of the lubricating oil guiding member 20 relative to the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15 is easily adjusted by modifying a size of the annular protruding portions 25 and by adjusting a bending rigidity of the lubricating oil guiding member 20. The lubricating oil supply device of the present invention is not limited to the above-described configuration, but, a contacting force of the lubricating oil guiding member 20 relative to the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15 at the outer circumferential surface of the lubricating oil guiding member 20 may be adjusted by adjusting the bending rigidity of the lubricating oil guiding member 20, specifically by modifying a thickness of each of the cylindrical portions 21, without providing the annular protruding portions 25.
In the above-described embodiment, the annular first sealing protrusions 26a1 and 26a2, which slidably contact the inner side surfaces of the accommodating groove 18, are formed at the outer surfaces of both cylindrical portions 21 facing the opposite direction from each other. Further, the annular second sealing protrusions 26b1 and 26b2, which slidably contact the corresponding inner side surfaces of the annular grooves 18a, are formed at the inner surfaces of both the annular protruding portions 25 facing each other, respectively. Accordingly, even if the lubricating oil guiding member 20 is offset to one side in the lateral direction (i.e. in the axial direction of the rotational shaft 15) because of the manufacturing error, the misassembling and the like, and he leakage of the lubricating oil is surely prevented. The lubricating oil supply device of the present invention is not limited to the above-described configuration, but one of or both of the first and the second sealing protrusions 26a1, 26a2 and 26b1, 266b2 may be eliminated from the cylindrical portions 21 by improving a sealing effect and function, or by improving a manufacturing accuracy, an assembling accuracy and the like.
In the above-described embodiment, a case where the lubricating oil is supplied to the center bore 17 provided at the output shaft 15 of the transmission apparatus is described. In this case, lubrication of the needle roller bearing 7a, which is provided between the input shaft 7 and the output shaft 15 and at which a lack of lubrication occurs because the needle roller bearing 7a is arranged at a position hard to be lubricated, is appropriately and surely achieved. The lubricating oil supply device of the present invention is not limited to the above-described configuration, but the lubricating oil supply device may be configured to supply the lubricating oil to a center bore provided at, for example, the input shaft 7, the counter shaft and the like of other components of a vehicle necessitating lubrications. Accordingly, the lubricating oil supply device of the present invention is adaptable to the shift gears, the synchromesh mechanisms and the like rotatably provided at, for example, the input shaft 7, the counter shaft and the like.
Accordingly, although the lubricating oil guiding member 20 is rotated together with the output shaft 15, the flowing speed of the lubricating oil flowing closer to the transmission housing 10 is slowed relative to the flowing speed of the lubricating oil flowing closer to the outer circumferential surface of the lubricating oil guiding member 20 because of the viscous friction generated between the lubricating oil existing within the rotating lubricating oil guiding member 20 and the lubricating oil existing within the cylindrical bore 12. As a result, the lubricating oil is moved towards the forward inner side surfaces 22a formed at the corresponding guide holes 22 when the output shaft 15 is rotated in the positive direction. The lubricating oil hits the forward inner side surfaces 22a, which is connected to the outer circumferential surface 21a of each of the cylindrical portions 21 and forms the acute angle relative to the outer circumferential surface 21a thereof, so that the lubricating oil is smoothly directed inwardly in the radial direction thereof. Accordingly, the lubricating oil is guided to the center bore 17 through the discharge passages 17a so as to resist against the centrifugal force generated by the rotation of the output shaft 15, thereby lubricating the needle roller bearing 7a. Further, only the lubricating oil guiding member 20 is additionally provided at the conventional lubricating oil supply device. Therefore, the lubricating oil supply device appropriately and surely lubricating the needle roller bearing 7a is achieved with a few additional manufacturing costs.
According to the embodiment, the lubricating oil guiding member 20 is rotated with the rotational shaft 15 by engaging the protrusions 24 or a recessed portion, formed at the inner circumferential surface of the lubricating oil guiding portion 20 or the cylindrical portion 21, with the recessed portions 18b or a protrusion, formed at the bottom surface of the accommodating groove 18 or a portion of the accommodating groove 18 corresponding to the cylindrical portion 21.
The lubricating oil guiding member 20 is simultaneously rotated with the output shaft 15 by engaging the protrusions 24 or a recessed portion, formed at the inner circumferential surface of the lubricating oil guiding member 20 or formed at the bottom surface of the protruding portion 25 facing the output shaft, with the recessed portions 18b or a protrusion, formed at the bottom portion of the accommodating groove 18 or the bottom portion of the annular groove 18a. Accordingly, the connecting structure of the lubricating oil guiding member 20 relative to the output shaft 15 is achieved with a simple structure. Further, the lubricating oil guiding member 20 is structured to be rotated with the output shaft 15 when the lubricating oil guiding member 20 is assembled on the output shaft 15 only by engaging the protrusions 24 and the recessed portions 18b.
According to the embodiment, the lubricating oil guiding member is made of the synthetic resin, having the abrasion resistance and the elasticity, and is formed in the C-shape by providing the cut 20a at a portion of the lubricating oil guiding member 20 in the circumferential direction thereof so that the cut 20a extends in the axial direction of the output shaft 15, so that the lubricating oil guiding member 20 elastically contacts the inner circumferential surface of the end casing portion 10b corresponding to the position where the cylindrical bore 12 is formed.
The lubricating oil guiding member 20 is made of the synthetic resin having the abrasion resistance and the elasticity. Further, the lubricating oil guiding member 20 is formed to have the C-shape by providing the cut 20a thereat, and the outer circumferential surface of the lubricating oil guiding member 20 elastically contacts the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15, thereby forming very little clearance therebetween. As a result, the amount of the lubricating oil, moving through the lubricating oil guiding member 20, leaking outward therefrom is greatly reduced.
According to the embodiment, the cut 20a is provided at the position corresponding to one of the guide hole 22 formed at the lubricating oil guiding member 20 so that one end surface of the cut 20a is arranged so as to correspond to the forward inner side surface 22a.
The cut 20a is formed at the position corresponding to one of the guide holes 22 so that one side surface of the cut 20a is inclined so as to correspond to the inclination of one of the forward inner side surfaces 22a. Accordingly, the forward inner side surfaces 22a, which are connected to the corresponding outer circumferential surfaces 21a that are formed at the outermost positions in the radial direction of the cylindrical portions 22 and which changes the moving direction of the lubricating oil inwardly in the radial direction of the lubricating oil guiding member 20, closely contact the inner circumferential surface of the inner circumferential surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15. Therefore, the lubricating oil is effectively directed inwardly in the radial direction of the lubricating oil guiding member 20 while reducing the amount of leakage of the lubricating oil to a minimum.
According to the embodiment, the lubricating oil guiding member 20 includes two of the cylindrical portions 21 extending along the circumferential direction of the lubricating oil guiding member 20, the pair of annular protruding portions 25 is provided at the inner circumferential surface of the pair of cylindrical portions 21, respectively, so as to extend along both sides of the guide holes 22, and the pair of annular grooves 18a is formed at the bottom surface of the accommodating groove 18 for accommodating the pair of the annular protruding portions 25, respectively.
The pair of annular protruding portions 25 protruding inwardly in the radial direction of the lubricating oil guiding member 20 is provided at the pair of the cylindrical portions 21, respectively, so as to be arranged at the positions corresponding to the both sides of the guide holes 22. Further, the pair of annular grooves 18a for accommodating the corresponding annular protruding portions 25 is formed at the bottom surface of the accommodating groove 18. Accordingly, the contacting force of the outer circumferential surface of the lubricating oil guiding member 20 relative to the inner side surface of the end casing portion 10b corresponding to the second step portion of the output shaft 15 is easily modified by modifying the size of the annular protruding portions 25.
According to the embodiment, at least one of the outer side surfaces of the pair of cylindrical portions 21 facing opposite direction from each other is provided with the first sealing protrusion 26a1 and 26a2 that are formed in the annular-shapes and slidably contact the corresponding inner side surfaces of the accommodating grove 18, and at least one of the inner side surfaces of the annular protruding portions 25 facing each other is provided with the second sealing protrusion 26b1 (26b2) that is formed in the annular-shape and slidably contacts the corresponding inner side surface of the annular groove 18a facing the other inner side surface of the annular groove 18a.
The pair of first sealing protrusions 26a1 and 26a2, which slidably contact one of the inner side surfaces of the accommodating groove 18 facing each other in the axial direction of the output shaft 15, is formed at the outer side surface of each of the cylindrical portions 21 facing opposite direction from each other in the axial direction of the output shaft 15. Further, the second sealing protrusions 26b1 and 26b2, which slidably contact the inner side surfaces of the annular grooves 18a, respectively, are formed at the inner side surfaces of the annular protruding portions 25, respectively. Accordingly, in a case where the lubricating oil guiding member 20 is offset to one side in the axial direction of the output shaft 15 relative to the accommodating groove 18 and where either one of the pair of the first sealing protrusions 26a1 and 26a2 is positioned away from the corresponding inner side surface of the accommodating groove 18, the second sealing protrusions 26b1 or 26b2 formed at the annular protruding portion 25 corresponding to the one of the pair of the first sealing protrusions 26a1 and 26a2 contacts the corresponding inner side surface of the annular groove 18. As a result, leakage of the lubricating oil, occurring due to the offset of the lubricating oil guiding member 20 to one side in the axial direction of the output shaft 15, is prevented from occurring.
According to the embodiment, the center bore 17 is provided at the output shaft 15 so as to open to the inner end surface thereof, the bearing hole 17b having the larger diameter than the diameter of the center bore 17 is formed at the position where the center bore 17 opens to the inner end surface of the output shaft 15, and the end portion of the input shaft 7, arranged in the coaxial manner with respect to the output shaft 15, is rotatably supported at the bearing hole 17b via the needle roller bearing 7a, thereby transmitting a shifted rotation of the input shaft 7 to the output shaft 15.
The output shaft 15 includes the center bore 17 opening to the inner end surface of the output shaft 15. Further, the end portion of the input shaft 7 coaxially arranged relative to the output shaft 15 is rotatably supported at the bearing hole 17b, which is formed at the opening of the center bore 17 so as to spatially and integrally extend towards the center bore 17 and which is formed to have a larger diameter than a diameter of the center bore 17, via the needle roller bearing 7a, so that the shifted rotation of the input shaft 7 is transmitted to the output shaft 15. Accordingly, the needle roller bearing 7a, which is provided between the output shaft 15 and the input shaft 7 and at which a lack of lubrication occurs because the lubricating oil is hard to be supplied thereto, is appropriately lubricated.
The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the sprit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.
Number | Date | Country | Kind |
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2007-237021 | Sep 2007 | JP | national |