JP2017096243A - Cam shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a high-speed production to be carried out by a former of hollow shaft, attain a cost reduction and a light weight formation, and perform a rigid fixing of a high precision hollow shaft and a cam through an involute serration fitting.SOLUTION: There are provided a hollow shaft formed with an involute serration shaft part at its outer peripheral portion, hollow oil distribution hole extending in an axial direction formed in it and formed with a communication hole opened from the oil distribution hole to the outer peripheral part and a cam having a semi-circular base surface and a semi-elliptical convex surface protruded from the base surface in a radial direction, an involute serration hole formed at a central part of the base surface and an oil supply hole opened from the serration hole to the outer peripheral surface, the hollow shaft is formed through a plurality of consistent forging steps from one blank by the former and the hollow shaft and the cam are fixed through the involute serration fitting.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an internal oil supply type camshaft used mainly for opening and closing intake and exhaust valves in an engine.

Conventionally, this type of internal oil supply type camshaft includes, for example, a hollow shaft portion and a cam portion integrally formed with the hollow shaft portion. The cam portion is communicated with the hollow portion of the hollow shaft portion and the hollow portion. The thing of the structure which has the oil supply hole opened to the outer peripheral surface of this is known.
When the lubricating oil is fed into the hollow shaft portion of the camshaft, the lubricating oil is injected from the oil supply hole, whereby the sliding surface between the cam portion and the driven member can be lubricated.

  JP-A-9-250626

  However, according to the above-described conventional internally lubricated camshaft, a camshaft having a complicated shape composed of a shaft portion and a cam portion is integrally formed by casting, and then the cam portion is subjected to heat treatment to partially reduce its hardness. It had to be reinforced and machined to form oil holes. For this reason, there is a problem that not only the molding accuracy is poor but also the production is complicated and the production cost is high, the production takes a lot of time and the weight is also increased.

  Therefore, the present invention was invented to solve the above-mentioned problems, and the hollow shaft and the cam were formed by separate members, and the hollow shaft having the involute serration shaft portion on the outer peripheral portion was consistently formed from one blank by the former. Formed in multiple forging processes, and a cam with an involute serration hole is pushed into and fixed to the involute serration shaft, which enables high-speed production of hollow shafts with involute serration shafts, reducing costs. It is an object of the present invention to provide a camshaft that can be reduced in weight and can be firmly fixed by involute serration fitting with a highly accurate hollow shaft and cam that are individually manufactured.

  In the invention according to claim 1 of the present application, an involute serration shaft portion is formed on the outer periphery, a hollow oil distribution hole extending in the axial direction is formed inside, and a through hole opening from the oil distribution hole to the outer periphery is formed. An internally lubricated hollow shaft formed, a semicircular base surface and a semi-elliptical convex surface projecting radially from the base surface, and an involute serration hole is formed at the center of the base surface; and The camshaft is provided with an oil supply hole that opens from the involute serration hole to the outer peripheral surface, and the hollow shaft excluding the through hole is formed from a single blank by a plurality of forging processes consistently by a former, and is hollow. Insert the cam involute serration hole into the shaft involute serration shaft and push the cam into the hollow shaft to fix it. Characterized in that it was.

  In the invention according to claim 2 of the present application, the cam according to claim 1 is composed of two inner divided bodies, two outer divided bodies and two caulking pins divided in the width direction, and the inner divided body. Has a cam surface including a semi-circular base surface and a semi-elliptical convex surface projecting radially from the semi-circular base surface, and an involute serration hole is formed at the center of the semi-circular base surface and the convex surface A communication groove communicating with the involute serration hole and a pair of oil supply grooves extending perpendicularly from the vicinity of the front end of the communication groove and opening to the cam surface are formed in communication with the side butting surface. A partially cut semicircular base surface formed by notching the outer peripheral intermediate portion corresponding to the semicircular base surface of the divided body into a small diameter via a stepped portion and a half protruding radially from the partially cut semicircular base Cam surface including an elliptical convex surface Involute serration holes are formed in the center of the semicircular base surface side, and the inner and outer divided bodies are each formed by punching by thin plate precision press, while the two inner parts The divided bodies are overlapped so that the communication groove and the oil supply groove coincide with each other on the inside, and the outer divided bodies are overlapped on the outside so that the contours coincide with each other, and these divided bodies are integrated by fixing means in the stacked state. It is characterized by being fixed.

  According to a third aspect of the present invention, the cam according to the first aspect of the present invention is composed of two inner divided bodies, two outer divided bodies and two crimping pins divided in the width direction, and the inner divided body. Has a cam surface including a semi-circular base surface and a semi-elliptical convex surface projecting radially from the semi-circular base surface, and an involute serration hole is formed at the center of the semi-circular base surface and the convex surface A through hole is formed in the center of the side, a communication groove communicating with the through hole from the involute serration hole on the abutting surface, and a pair of oil supply grooves extending orthogonally from the vicinity of the through hole of the communication groove and opening to the cam surface Are formed in communication with each other, and the outer divided body has a partially cut semicircular base surface formed by cutting out an outer peripheral intermediate portion corresponding to the semicircular base surface of the inner divided body into a small diameter via a stepped portion. Partially cut from semicircular base to diameter Having a cam surface including a semi-elliptical convex surface projecting in the direction, an involute serration hole is formed in the central portion on the semicircular base surface side, and a through hole is formed in the intermediate portion on the convex surface side, Of these, the outer divided bodies are each formed by punching, while the two inner divided bodies are overlapped so that the communication grooves, the oil supply grooves, and the through holes coincide with each other on the inner side, and on the outer side. The outer divided bodies are overlapped so that the outlines coincide with each other, and in the laminated state, caulking pins are inserted into the through holes in these divided bodies and fixedly joined.

  According to the above-described camshaft of the present invention, the hollow shaft and the cam are formed by separate members, and a hollow shaft having an involute serration shaft portion on the outer peripheral portion is formed from a single blank into a plurality of consistent Formed in the forging process and configured to push and fix a cam with an involute serration hole on the involute serration shaft part, enabling high-speed production of a hollow shaft with an involute serration shaft part and cost reduction It is possible to reduce the weight. In addition, the hollow shaft and the cam manufactured individually can be firmly fixed by involute serration fitting.

  According to the camshafts of the second and third aspects of the present invention, in addition to the above-described effects, the two cams are formed with high precision by punching with a thin plate precision press, and the two outer cams are formed. Since it is configured by layering the divided body, the cam shape can be easily changed while obtaining high molding accuracy without increasing the shape of the cam like a cam formed by integral molding, and the manufacturing cost is also low. Can be. Further, since the outer divided body has a partially cut semicircular base surface formed by cutting out the outer peripheral intermediate portion corresponding to the semicircular base surface of the inner divided body in a small diameter shape through the stepped portion, the cam itself Weight reduction can be achieved. In addition, when the two inner divided bodies are overlapped, the communication groove and the oil supply groove formed at the time of punching match each other at the mating surface, thereby forming an oil supply hole that opens from the involute serration hole to the outer peripheral surface. This eliminates the need for special machining for forming the oil supply holes in the subsequent process.

  Further, according to the camshaft according to claim 3 of the present invention, the inner abutting surface of the inner divided body has a communication groove that communicates from the involute serration hole to the through hole for the caulking pin, and is orthogonal from the vicinity of the through hole of the communication groove. A pair of oil supply grooves extending to the cam surface and communicating with each other are formed in communication, so that the lubricating oil passing through the communication groove from the involute serration hole hits the top of the caulking pin and is distributed to both sides. It will be sent smoothly to the groove. Thus, the cam surface is reliably and evenly supplied through the pair of oil supply grooves.

It is a schematic explanatory drawing of a camshaft in the present invention. It is the sectional view on the AA line of FIG. It is a front view of a cam. It is a front view of an inner side division body. It is the same side view. It is a front view of an outer side division body. It is the same side view.

  Embodiments of a camshaft according to the present invention will be described below with reference to the drawings.

  In FIG. 1, reference numeral 1 denotes an internal oil supply type camshaft according to the present invention. The camshaft 1 includes a hollow shaft 2 and a cam 3.

  In the hollow shaft 2, an involute serration shaft portion 21b is formed on the outer periphery of a hollow shaft main body 21 in which a hollow oil distribution hole 21a extending in the axial direction is formed, and the involute serration shaft portion 21b is formed from the oil distribution hole 21a. A through hole 21c is formed in the outer periphery of the predetermined position. The hollow shaft 2 has a high accuracy without material loss by integrally forming the hollow shaft main body 21 and the involute serration shaft portion 21b on the outer peripheral surface in a plurality of forging processes that are consistently performed by a former from a single blank. To be molded. The through hole 21c is formed by machining in a later process.

  As shown in FIGS. 1 to 3, the cam 3 includes two inner divided bodies 31, 31 and two outer divided bodies 32, 32 divided into four in the width direction, and inner and outer divided bodies 31, 31, It is comprised from the crimping pin 4 which fixes 32 and 32 in a lamination | stacking state.

  Specifically, as shown in FIGS. 4 and 5, the inner divided body 31 has a cam surface 31c including a semicircular base surface 31a and a semi-elliptical convex surface 31b protruding radially from the semicircular base surface 31a. An involute serration hole 31d is formed in the central portion on the semicircular base surface 31a side, and a rectangular through hole 31e penetrating in the axial direction is formed in the central portion on the convex surface 31b side. A communication groove 31f communicating from the serration hole 31d to the through hole 31e and a pair of left and right oil supply grooves 31g and 31g extending orthogonally from the vicinity of the through hole 31e of the communication groove 31f and opening to the cam surface 31c are formed in communication. When the pair of left and right oil supply grooves 31g, 31g are provided, they may be provided so as to be opened with an angle so as to be inclined slightly toward the center side of the convex surface 31b instead of being orthogonal to the communication groove 31f. .

  The outer divided body 32 has a partially cut semicircular base surface formed by notching the outer peripheral intermediate portion corresponding to the semicircular base surface 31a of the inner divided body 31 to a small diameter via the step portions a and a. 32a and a semi-elliptical convex surface 32b projecting radially from the partially-cut semicircular base 32a, and an involute serration hole 32d is formed at the center of the semicircular base surface side 31a. In addition, a rectangular through hole 32e penetrating in the axial direction is formed in an intermediate portion on the convex surface 32b side.

  Out of these, the outer divided bodies 31, 31, 32, 32 are each formed by punching a thin plate with a high-precision precision press, and are formed with high molding accuracy without any drooping. Further, a communication groove 31f that communicates from the involute serration hole 31d to the through hole 31e in the inner divided body 31 and a pair of left and right oil supply grooves 31g and 31g that extend orthogonally from the vicinity of the through groove 31e of the communication groove 31f and open to the cam surface 31c. Are simultaneously formed by stamping at the time of punching.

  The two inner divided bodies 31 and 31 are overlapped so that the communication groove 31f and the oil supply groove 31g coincide with each other on the inner side, and the outer divided bodies 32 and 32 are overlapped on the outer sides so that the contours thereof coincide with each other. In the laminated state, caulking pins 4 having a quadrangular cross section are inserted into the through holes 31e, 31e, 32e, and 32e in these divided bodies, and the inner and outer divided bodies 31, 31, 32, and 32 are joined and fixed.

Next, assembly of the hollow shaft 2 and the cam 3 will be described.
As shown in FIGS. 1 and 2, the involute serration shaft portion 21b of the hollow shaft 2 is fitted with the involute serration holes 31d and 32d of the cam 3, and the cam 3 is pushed into the hollow shaft main body 21 of the hollow shaft 2 to the side. Secure in the fitted state. At this time, alignment is performed so that the through hole 21c formed in the involute serration shaft portion 21b and the through grooves 31e and 31e formed in the two inner divided bodies 31 and 31 of the cam 3 coincide.

  According to the camshaft 1 of the present invention configured as described above, the hollow shaft 2 and the cam 3 are formed by separate members, and the hollow shaft 2 having the involute serration shaft portion 21b on the outer peripheral portion is formed from one blank by a former. The involute serration shaft portion is formed by a plurality of consistent forging processes, and the involute serration shaft portion 21b is configured to push and fix the cam 3 made of a separate member and having the involute serration holes 31d, 31d, 32d, and 32d. High-speed production of the hollow shaft 2 having 21b is possible, and cost reduction and weight reduction can be achieved. In addition, the hollow shaft 2 and the cam 3 manufactured individually can be firmly fixed by involute serration fitting.

  Further, the cam 3 is formed by laminating two inner divided bodies 31 and 31 and two outer divided bodies 32 and 32 formed with high precision by punching with a thin plate precision press, and these are joined and fixed by caulking pins 4. As a result, the cam shape can be easily changed while high molding accuracy can be obtained without the need to increase the shape of the cam as in conventional cams formed by integral molding, and the manufacturing cost is also low. Can be. Further, the outer divided bodies 32, 32 are partially cut semicircular shapes formed by notching outer peripheral intermediate portions corresponding to the semicircular base surfaces 31a, 31a of the inner divided bodies 31, 31 to a small diameter via a stepped portion. Since the base surfaces 32a and 32a are used, the weight of the cam 2 itself, in other words, the weight of the camshaft 1 can be reduced. In addition, when the two inner divided bodies 31 and 31 are overlapped, the communication groove 31 and the oil supply groove 31g formed at the time of the punching process coincide with each other at the mating surface, so that the cam surface 31c from the involute serration hole 31d. The oil supply hole which opens two places will be formed in the outer surface of this. This eliminates the need for special machining for forming the oil supply holes in a later step as in the prior art.

  Further, in the above-described embodiment, as shown in FIG. 2, the inner butted surfaces of the inner divided bodies 31 and 31 communicate with the communication groove 31f that communicates from the involute serration hole 31d to the rectangular through hole 31e for the caulking pin 4. Since a pair of left and right oil supply grooves 31g, 31g extending orthogonally from the vicinity of the through hole 31e of the groove 31f and opening to the cam surface 31c are formed in communication, the lubricating oil passing through the communication groove 31f from the involute serration hole 31d is The caulking pin 4 is distributed to the left and right sides at the top of the caulking pin 4 and sent to a pair of left and right oil supply grooves 31g, 31g, and is smoothly supplied to the left and right portions of the cam surface 31c through these oil supply grooves 31g, 31g. Thus, the oil is reliably and evenly supplied to the two left and right portions of the cam surface 31c through the pair of oil supply grooves 31g and 31g.

  In the above-described embodiment, as a means for fixing the cam 3 to the hollow shaft 2, the involute serration holes 31 d and 32 d of the cam 3 are forcibly fitted and fixed to the involute serration shaft portion 21 b of the hollow shaft 2. However, as a matter of course, other appropriate fixing means such as welding or crimping may be used. Also, as fixing means for the inner and outer divided bodies 31, 31, 32, 32, one piece to the rectangular through holes 31e, 31e, 32e, 32e formed in the inner and outer divided bodies 31, 31, 32, 32 However, the shape, position, and number of the through holes (caulking holes) 31e, 31e, 32e, 32e and the caulking pins 4 are not limited at all. For example, a circular shape is used. A plurality of through holes and caulking pins may be provided regardless of the communication groove 31f and the oil supply grooves 31g, 31g. Furthermore, as the fixing means for the inner and outer divided bodies 31e, 31e, 32e, 32e, other fixing means such as welding or fitting and fitting of concavo-convex portions may be used in addition to the caulking fixing by the caulking pin 4.

1 cam shaft 2 hollow shaft 3 cam 4 caulking pin (fixing means)
21 hollow shaft body 21a hollow oil distribution hole 21b involute serration shaft portion 21c through hole 31 inner divided body 31a semicircular base surface 31b convex surface 31c cam surface 31d involute serration hole 31e through hole 31f communication groove 31g oil supply groove (oil supply hole)
32 Outer divided body 32a Partially cut semicircular base surface 32b Convex surface 32c Cam surface 32d Involute serration hole 32e Through hole

Claims (3)

  An internally lubricated hollow shaft having an involute serration shaft portion formed on the outer periphery, a hollow oil distribution hole extending in the axial direction inside, and a through hole opening from the oil distribution hole to the outer periphery. And a semicircular base surface and a semi-elliptical convex surface projecting radially from the base surface, an involute serration hole is formed in the center of the base surface, and an oil supply that opens from the involute serration hole to the outer peripheral surface The hollow shaft excluding the through-hole is formed by a plurality of forging processes that are consistently performed by a former from a single blank, and the cam involute is formed on the involute serration shaft of the hollow shaft. A camshaft characterized by inserting a serration hole and pushing the cam into the hollow shaft. Shift.   The cam is composed of two inner divided bodies divided into four in the width direction, two outer divided bodies, and caulking pins, and the inner divided body projects radially from the semicircular base surface and the semicircular base surface. A communication groove having a cam surface including a semi-elliptical convex surface, an involute serration hole is formed at the center of the semicircular base surface side, and a communication groove communicating with the involute serration hole on the convex-side abutting surface and the communication groove A pair of oil supply grooves that extend orthogonally from the vicinity of the tip of the inner surface and open to the cam surface are formed in communication with each other, and the outer divided body has a stepped portion at the outer peripheral intermediate portion corresponding to the semicircular base surface of the inner divided body. A semicircular base surface having a cam surface including a partially cut semicircular base surface that is cut out in a small diameter via a semi-elliptical convex surface that protrudes radially from the partially cut semicircular base Involute in the center of the side The inner and outer divided bodies are each formed by stamping with a thin plate precision press, while the two inner divided bodies have their communication grooves and oil supply grooves inside. And overlapping the outer divided bodies so that their outlines coincide with each other, and fixing the divided bodies integrally by a fixing means in the stacked state. The camshaft according to 1.   The cam is composed of two inner divided bodies divided into four in the width direction, two outer divided bodies, and caulking pins, and the inner divided body projects radially from the semicircular base surface and the semicircular base surface. It has a cam surface including a semi-elliptical convex surface, an involute serration hole is formed in the center of the semicircular base surface side, a through hole is formed in the central portion of the convex surface side, and an involute serration is formed in the butted surface A communication groove that communicates from the hole to the through hole and a pair of oil supply grooves that extend orthogonally from the vicinity of the through hole of the communication groove and open to the cam surface are formed in communication with each other. A semi-elliptical part projecting radially from a partially-cut semicircular base surface and a partially-cut semi-circular base surface formed by notching the outer peripheral middle part corresponding to the semi-circular base surface into a small diameter through a stepped part Having a cam surface including a convex surface An involute serration hole is formed in the center of the semicircular base surface side, and a through hole is formed in the intermediate part on the convex surface side. Of these, each of the outer divided bodies is stamped by a precision press of a thin plate. On the other hand, the two inner divided bodies are overlapped so that the communication groove, the oil supply groove, and the through hole coincide with each other on the inside, and the outer divided bodies are overlapped on the outer side so that the contours coincide with each other. 2. The camshaft according to claim 1, wherein a caulking pin is fitted and fixed in the through hole in the divided body in the laminated state.

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