JP4117741B2 - Camshaft end piece and camshaft - Google Patents

Description

  The present invention relates to an end piece of a camshaft and a camshaft used in an internal combustion engine.

  A camshaft is used in a valve operating device of an internal combustion engine (engine). In order to contribute to improving the fuel consumption of an internal combustion engine, camshafts are required to have improved wear resistance, scuff resistance, and pitting resistance.

  For these required qualities, from the cast iron camshaft, the wear resistance, scuff resistance, etc. of each cam lobe has been remarkably improved. Camshafts are known. There is also known an assembly camshaft in which a cam lobe is press-fitted by shrink fitting. Further, there is also known a joining camshaft that is fixed by deforming a cam lobe joint portion of the camshaft shaft portion into a convex shape and plastically deforming the convex portion when the cam lobe is press-fitted. In any camshaft, in addition to the cam lobe, a journal portion and, if necessary, components for an angle sensor are set.

  At least one end of the shafts of these camshafts is usually provided with a member called an end piece, connected to the sprocket via the end piece, and the camshaft is rotated by driving the endpiece.

  Here, in the cast iron camshaft, the portion corresponding to the end piece is integrally formed from a material, and a tap hole for fixing the sprocket and a pin hole for positioning the sprocket are formed by machining.

  In the sintered camshaft, the assembly camshaft, and the joining camshaft described above, the end piece is joined to the journal portion and, if necessary, the camshaft portion in which the components for the angle sensor are formed, in addition to the cam lobe.

  As one aspect of the above-described assembly cam shaft, an assembly type cam shaft in which an end piece is joined to a hollow shaft by press fitting is known (for example, see Patent Document 1). The assembly-type camshaft disclosed in Patent Document 1 secures a joining strength between the endpiece and the camshaft and a lubricating oil passage by devising the shape of the endpiece.

On the other hand, as a cam shaft provided with an end piece, as shown in FIG. 5, a cam shaft 52 of a type that joins an end piece 51 and a shaft portion 53 of the cam shaft 52 by a friction welding method is known. Since the shaft portion 53 of the camshaft 52 is a hollow shaft, an oil hole 54 is usually provided in the end piece 51 as a passage for lubricating oil passing through the shaft portion 53. Further, the end piece 51 usually has a screw hole (hereinafter referred to as a tap hole) 55 at an end portion 58 on the side where the camshaft shaft 53 is not provided. Therefore, in order to prevent the oil hole 54 from communicating with the tap hole 55, the oil hole 54 is directed from the outer side to the inner side of the end piece 51, and is directed from the far side to the closer side to the hollow shaft 53 of the cam shaft 52. 52 may be provided obliquely with respect to the axial direction C of 52.
Japanese Utility Model Publication No. 58-73914

  In the end piece 51 of the camshaft 52 in which the oil hole 54 is provided obliquely with respect to the axial direction C of the camshaft 52 described above, the position, size, and processing method of the oil hole 54 when the oil hole 54 is processed. And so on. For example, regarding the position and size of the oil hole 54, the position outside the oil hole 54 needs to be in the oil groove 56 formed outside the end piece 51, and for opening the oil hole 54. It is necessary to prevent a tool such as a drill folder from hitting the flange portion 57 or the like that is formed in a convex shape on the outside of the end piece 51. Further, in the processing of the oil hole 54, the oil hole 54 extends obliquely with respect to the axial direction C. Therefore, it is necessary to form a pilot hole, and the burr treatment inside the end piece 51 of the formed oil hole 54 is performed. Since it is necessary, the number of processing increases.

  Therefore, the present invention is suitable for a camshaft that joins an end piece and a shaft portion by a friction welding method, reduces the number of processing in the processing of the oil hole of the end piece, and in the position and size of the oil hole. It is an object of the present invention to provide a camshaft end piece and a camshaft provided with the end piece with reduced constraints.

  An end piece of a camshaft of the present invention that solves the above problem is an endpiece connected to at least one end of a shaft portion of the camshaft, and the endpiece is a hollow portion connected to the shaft portion of the camshaft, and A tap hole having an inner diameter smaller than an inner diameter of the hollow portion at an end portion of the hollow portion not connected to the shaft portion, and the tap hole at an end portion of the hollow portion not connected to the shaft portion. An oil hole having a groove on the outer side and connecting from the groove to a journal portion that holds the rotation of the camshaft outside the end piece is provided substantially perpendicular to the axis of the hollow portion.

  The camshaft of the present invention that solves the above problems is a camshaft having an end piece connected to at least one end of a shaft portion, the end piece being a hollow portion connected from the shaft portion of the camshaft, and the hollow portion A tap hole having an inner diameter smaller than the inner diameter of the hollow portion at an end portion of the hollow portion that is not connected to the shaft portion, and a groove on the outer side of the tap hole at the end portion of the hollow portion that is not connected to the shaft portion. And an oil hole connected to the journal portion that holds the rotation of the camshaft outside the end piece from the groove is provided substantially perpendicular to the axis of the shaft portion.

  According to these inventions, the oil hole is provided outside the tap hole at the end portion of the end piece that is not connected to the shaft portion, and the oil hole connected from the groove to the outside of the end piece is the shaft of the hollow portion. Providing substantially perpendicular to the core eliminates the need for pilot hole processing and simplifies the burr processing inside the end piece, thus simplifying the processing of the oil hole in the end piece.

  In addition, since the oil hole can be opened substantially perpendicularly to the axial center of the hollow part from the outside of the end piece, the position outside the oil hole can be put into an oil groove formed outside the end piece, such as a drill folder. The oil hole can be formed without worrying about the positional relationship of the tools.

  Thus, according to the present invention, it is suitable for a camshaft that joins an end piece and a hollow shaft by a friction welding method, and includes an end piece that secures an oil hole that is a passage for lubricating oil, and an end piece. A camshaft can be easily manufactured.

  As described above, according to the camshaft end piece and the camshaft of the present invention, the number of processes in the processing of the oil holes in the end piece is reduced and the position and size of the oil holes are restricted by a simple configuration. Therefore, the oil hole can be manufactured with less restrictions.

  The camshaft end piece and camshaft of the present invention will be described below with reference to the drawings.

  First, FIG. 1A shows a cross-sectional view of a camshaft including an end piece of the present invention, and FIG. 1B shows a cross-sectional view of a part of the end piece. 2 (A) to 2 (C) are cross-sectional views illustrating modified embodiments of the end piece of the present invention.

  As shown in FIG. 1A, in the camshaft 10 of the present invention, the end piece 20 and at least one end of the shaft portion 30 of the hollow shaft are usually joined by a friction welding method (FIG. 1A). (Refer to the friction welding part 40).

  1B, the end piece 20 includes a hollow portion 21 connected to the shaft portion 30 of the camshaft 10 and a hollow portion at the end portion 22 of the hollow portion 21 that is not connected to the shaft portion 30. The tapped hole 23 has an inner diameter d smaller than the inner diameter D of 21. Further, the end piece 20 has a groove 24 outside the tap hole 23 in the end portion 22 on the side not connected to the shaft portion 30 in the hollow portion 21, and holds the rotation of the camshaft 10 outside the end piece 20 from the groove 24. An oil hole 25 connected to the journal portion 201 is provided substantially perpendicular to the axis C of the hollow portion 21.

  The shape of the groove 24 provided in the end piece 20 is not particularly limited. For example, a substantially triangular cross section 24 with a rounded tip as shown in FIG. 1A, an ellipse as shown in FIG. A cross section 24A having a cut shape, a substantially triangular cross section 24B having a sharp tip as shown in FIG. 2B, a substantially square cross section 24C having a flat tip as shown in FIG. It can be.

  The groove 24 provided in the end piece 20 may be provided in a circular shape at the end 22 along the inner periphery of the hollow portion 21, or provided only at a position corresponding to the position where the oil hole 25 is provided. Also good.

  The number of the oil holes 25 in the end piece 20 is at least two when referring to FIG. 1 (A) and the like, but is not limited to those shown in each figure, and is preferably one or more. The positional relationship when the oil holes 25 are provided at a plurality of locations is not particularly limited, but is usually provided at equal intervals. The oil hole 25 of the end piece 20, the hollow portion 21, and the hollow portion 32 of the shaft portion 30 serve as a passage for lubricating oil, and the journal portion 201 can be lubricated.

  Other shapes of the end piece 20 are not particularly limited, but two convex flange portions 26 that circulate around the outer peripheral portion of the hollow portion 21 and the tap hole 23 are provided with the oil hole 25 interposed therebetween, or on the outer side of the oil hole 25. An oil groove 27 may be provided. The flange portion 26 is provided to prevent the camshaft 10 from moving in the longitudinal direction of the shaft, and may have a convex shape as shown in FIGS. 1 and 2, but as shown in FIG. There may be a concave shape 28. Further, only one brim part 26 may be provided as shown in FIG. The oil groove 27 is a groove for supplying lubricating oil to the journal part 201, and is provided for discharging the lubricating oil to the shaft hollow parts 21 and 32 through the oil hole 25.

  In addition, the journal part 201 mentioned above is in the bearing of a transmission shaft, and says the part which slides (refer FIG. 1 (A), (B)). 3, the journal portion refers to the position from the position of the concave shape 28 to the position beyond the oil groove 27. In FIG. 4, the journal portion extends from the position of the flange portion 26 to a position beyond the oil groove 27. Say. As shown in FIG. 1 (A) and FIG. 4, it is preferable that the end of the journal portion on the side not having the shaft portion 30 has a slight groove.

  A hole 29 provided in the upper portion of the tap hole 23 of the end piece 20 shown in FIG. 1A or the like becomes a pin hole 29 for positioning a sprocket (not shown). The shape, size, and the like of the pin hole 29 are not particularly limited, and may be any shape, size, or the like suitable for sprocket positioning.

  A cam lobe 31 is usually provided at a predetermined position on the shaft portion 30 of the camshaft 10. Further, like the end piece 20, the shaft portion 30 of the camshaft 10 is provided with an oil hole (not shown) that serves as a lubricant passage. Other configurations of the camshaft 10 are not particularly limited.

  The dimension of each part of the camshaft 10 including the end piece 20 and the shaft part 30 of the present invention is not particularly limited, and in particular, the positional relationship between the groove 24 and the oil hole 25 may be as described above, and others are used. It is designed appropriately depending on the size of the internal combustion engine.

  The material of the end piece 20 of the present invention and the shaft portion 30 of the camshaft 10 is not particularly limited as long as it is normally used as the end piece 20 or the shaft portion 30 of the camshaft 10 of the internal combustion engine. A material made of steel material (S45C), carbon steel pipe STKM13 for machine structure, etc. is used.

  The camshaft to which the end piece of the present invention is applied is not particularly limited. For example, each cam lobe, journal portion, etc., and shaft portion are formed by sintering and baking. It can be applied to various types of camshafts, such as press-fitting assembled camshafts, and camshafts that are fixed by deforming the cam lobe joints of the camshaft shaft portion into a convex shape and plastically deforming the convex portions during cam lobe press-fitting. . The end piece of the present invention is applied to a camshaft of the type in which these camshaft and endpiece are formed separately and joined by friction welding. 1 (A) and the like show the friction welding parts 40 and 40 after the friction welding, but the end 40 of the end piece 20 and the end 40 of the shaft part 30 are friction welded, and FIG. A) The friction welding portions 40 and 40 shown in FIG.

  Although the manufacturing method of the end piece 20 of the present invention is not particularly limited, for example, the groove 24 is formed in a state where the hollow portion 21 of the end piece 20 is formed, and the oil hole 25 is formed from the outside toward the groove 24. It can be manufactured according to the procedure. Other shapes of the end piece 20 may be formed either before or after forming the hollow portion 21, the groove 24, and the oil hole 25 described above. The end piece 20 can be manufactured using a conventionally known tool such as a lathe or a drill.

  By forming the oil hole 25 in this order, the depth of the oil hole 25 can be stopped by the groove 24 when the oil hole 25 is processed, and the oil hole 25 is made to the axis C of the end piece 20. It can be formed substantially vertically. Since the oil hole 25 of the end piece 20 is formed substantially perpendicular to the axis C of the end piece 20, the position of the tool and the like are also taken care of even when the flange portion 26 is provided in the end piece 20. This increases the degree of freedom to select other configurations. Further, forming the oil hole 25 substantially perpendicular to the axis C does not require preparation of a prepared hole, and can be easily performed with a normal tool such as a drill. With such a configuration of the end piece 20, the oil hole 25 can be formed in a state before the end piece 20 is friction-welded with the shaft portion 30, and a work for removing a burr generated when the oil hole 25 is formed is also simple. Can be done.

  Thus, the manufacturing cost of the end piece 20 of the present invention and the camshaft 10 including the same is lower because the number of manufacturing steps is smaller than that of the conventional one. Further, it is possible to reduce the weight of the camshaft 10 by adjusting the size and the like of the groove 24 within a range where the strength is not affected by the groove 24 of the end piece 20.

It is sectional drawing of the camshaft containing the end piece of this invention. It is sectional drawing explaining the deformation | transformation form of the end piece of this invention. It is sectional drawing explaining the other deformation | transformation form of the end piece of this invention. It is sectional drawing explaining the further another deformation | transformation form of the end piece of this invention. It is sectional drawing which shows an example of the cam shaft containing the conventional end piece.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Camshaft 20 End piece 201 Journal part 21 Hollow part 22 End part of hollow part 23 Tap hole 24, 24A, 24B, 24C Groove 25 Oil hole 26 Collar part 27 Oil groove 28 Recessed part 29 Pin hole 30 Shaft part 31 Cam lobe 32 Shaft Hollow part 40 Friction welding part 51 Conventional end piece C shaft center

Claims (2)

An end piece connected to at least one end of the shaft portion of the camshaft,
The end piece has a hollow portion connected to the shaft portion of the camshaft, and a tap hole having an inner diameter smaller than the inner diameter of the hollow portion at an end portion of the hollow portion that is not connected to the shaft portion,
Having a groove on the outer side of the tap hole at the end portion on the side not connected to the shaft portion in the hollow portion,
An end piece of a camshaft characterized in that an oil hole connected from the groove to a journal portion that holds the rotation of the camshaft outside the endpiece is provided substantially perpendicular to the axis of the hollow portion. A camshaft having an end piece connected to at least one end of the shaft portion;
The end piece has a hollow portion connected to the shaft portion of the camshaft, and a tap hole having an inner diameter smaller than the inner diameter of the hollow portion at an end portion of the hollow portion that is not connected to the shaft portion,
Having a groove on the outer side of the tap hole in the end portion on the side not connected to the shaft portion in the hollow portion,
The camshaft is characterized in that an oil hole connected to the journal portion that holds the rotation of the camshaft outside the end piece from the groove is provided substantially perpendicular to the axis of the shaft portion.

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