JPH09303363A - Fixing structure of shaft and fitted member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide strong and assured fixing of a second flange and a cam while uniforming the outside diameters of a driving shaft and a camshaft. SOLUTION: A recess 60 is formed in the peripheral surface 21b of a driving shaft 21, and also a bolt insert hole 61 is penetratingly formed along a perpendicular direction (diametral direction) against the flat bottom surface 60a of the recess. While, a fitting and inserting hole 63 to which the head 62a of a bolt 62 is fitted and inserted is formed in the sleeve 32 of a second flange 28 which is fitted to the driving shaft 21 through a driving shaft inserting/passing hole 32a, and also a washer 64 whose diameter is enlarged through a slit according to the axial force of the bolt 62 is interposed between the head 62a of the bolt 62 and the bottom surface 64c of the recess, thereby the peripheral surface 21b is brought in pressure contact with the inner circumferential surface 63a of the fitting/inserting hole 63 by the deformation of the enlarged diameter of the washer 64.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a fixing structure for a camshaft of an internal combustion engine and a cam or the like fitted on the outer peripheral surface of the camshaft.

[0002]

2. Description of the Related Art As is well known, an internal combustion engine for an automobile is known to be equipped with a device for variably controlling the opening / closing timing of an intake / exhaust valve according to the operating state of the engine. As an example, the applicant of the present application previously filed 6-638
There is one described in No. 04.

The outline will be described with reference to FIG. 22. This intake / exhaust valve drive control device includes a hollow drive shaft 1 to which a rotational force is transmitted from a crank shaft of a multi-cylinder engine through a sprocket, and the drive shaft. A camshaft 2 is provided coaxially with the outer periphery of the shaft 1 so as to be relatively rotatable, and a control mechanism 3 is provided between divided ends of the camshaft 2 divided for each cylinder.

In the drive shaft 1, the drive shaft main body 1a is shown in FIG.
As shown in FIG. 1, the first journal 1f on the sprocket side is rotatably supported by a bearing (not shown) provided at the upper end of the cylinder head 7 in the longitudinal direction of the engine. The outer diameter of the drive shaft main body 1a from one end to the other end of the first journal 1f side is reduced in a step-like shape, and the first to fourth cylinders are arranged at equal intervals on the outer peripheral surface thereof. Spline projections 1b to 1e for cylinders are formed along the axial direction.

Each of the camshafts 2 has two intake valves 4, 4 per cylinder on its outer periphery, and valve lifters 4a, 4
a, two cams 6 and 6 that are opened against the spring force of the valve spring 5 are integrally provided, and are rotatably supported by a pair of cam bearings 8 and 9 on a cylinder head 7. Have been.

The control mechanism 3 includes an annular first flange 10 provided integrally with one end of each camshaft 2.
An annular second flange portion 13 which is spline-coupled to a predetermined outer peripheral position of the drive shaft 1 via a sleeve 12 and faces the first flange portion 10;
13, a substantially annular disk housing 14 interposed between the shafts 13 and provided so as to be swingable in a substantially radial direction from the axis X of the drive shaft 1.
And an annular disk 16 rotatably held via a plain bearing 15 in a large-diameter support hole 14a provided on the inner periphery of the disk housing 14. Each of the sleeves 12 has a spline groove 12 that fits into the spline protrusions 1b to 1e on the inner peripheral surface of the drive shaft insertion hole 12a.
b-12e are formed.

The disk housing 14 is rotatably supported at one end in the diameter direction by a support shaft (not shown) fixed to the upper end of the cylinder head 7, and has the other end centered on the support shaft. It swings by a drive mechanism. Further, the outer peripheral portions of the first and second flange portions 10 and 13 have elongated engaging grooves 17 and 1 at 180 ° positions with respect to each other.
8 are formed along the radial direction. On the other hand, pins 19 and 20 projecting from opposite sides of the annular disc 16 and projecting in opposite directions to engage with the engaging grooves 17 and 18 are provided.

Then, the annular disk 16 is concentrically or eccentrically moved with respect to the axis of the drive shaft 1 via the disk housing 14 by a drive mechanism (not shown) in response to a change in the engine operating state. The relative rotational phase between the motor and the camshaft 2 is changed. As a result, the operating angle of the intake valve is changed to a minimum and a maximum to control the valve opening timing and the valve closing timing, thereby improving the engine performance according to the operating state.

[0009]

However, in the above-mentioned conventional invention, the drive shaft 1 and each of the second flange portions 13 are provided.
Are spline-coupled via the sleeve 12, so that the spline grooves 12 b to 12 c on the inner periphery of the sleeve 12 are formed on the irregularities on the outer periphery of the spline projections 1 b to 1 e formed on the outer peripheral surface of the drive shaft main body 1 a. Since it is necessary to fit the unevenness of 12e from the axial direction, each adjacent spline projection 1
The outer diameter differences b to 1e must be set large.

That is, in order to assemble the respective second flange portions 13 to the drive shaft 1 in order from the inner diameter of the sleeve 12 having the larger inner diameter, the second flange portion 13 is fitted to the first spline projection portion 1b on the first journal 1f side. In order for the first sleeve 12 to pass the outer circumference of the second spline protrusion 1c, the inner diameter of the drive shaft insertion hole 12a thereof is set larger than the outer diameter of the second spline protrusion 1c, and the second spline protrusion 1c is also set. The inner diameter of the second sleeve 12 that fits in the above must be set larger than the outer diameter of the third spline protrusion 1d. For example, when fitting a flange and a sleeve using a spline having a module of 0.5, the nominal diameters of the spline protrusions 1b to 1e of the first to fourth spline protrusions are 22 mm, 20mm, 18mm, 15mm,
As a result, the adjacent spline protrusions 1b to 1e
The difference in outer diameter between the two becomes large.

For this reason, the diameter of the drive shaft 1 is inevitably increased from one end (the first journal 1f side) of the drive shaft main body 1a to the other end thereof. The outer diameter must be made sufficiently small.
As a result, the torsional rigidity (strength) of the drive shaft 1 may decrease, the valve timing control accuracy may decrease, and irregular movement such as bounce of the intake valve 4 may occur.

By the way, as a method of fixing a member such as a cam piece to a shaft such as the drive shaft as described above, a cam piece and a shaft are disclosed, for example, as disclosed in JP-A-61-282663. Some of them are fitted together and fixed by bulge molding, but this method necessitates an increase in molding equipment and a rise in manufacturing cost. Further, there is a problem that the torsional rigidity of the shaft is reduced as in the above because the molded shape and the outer diameter of the shaft are restricted and the diameter must be relatively small.

[0013]

The present invention has been devised in view of the above-mentioned conventional circumstances, and the invention of claim 1 is to fit the shaft and the outer peripheral surface of the shaft through a shaft insertion hole. And a fitting structure for fixing the fitting member to the fitting member, wherein a recess is formed at a predetermined position on the outer peripheral surface of the shaft, and the bolt insertion hole is penetrated from a direction perpendicular to the flat bottom surface of the recess in the radial direction. On the other hand, while forming, a fitting insertion hole into which the bolt head is fitted is formed in the peripheral wall of the fitted member corresponding to the recess,
Further, a washer is interposed between the head portion of the bolt and the bottom surface of the recess, the washer being expanded and deformed in accordance with the axial force of the bolt.

According to a second aspect of the present invention, the lower surface of the bolt head is formed into a substantially conical tapered surface, while the upper surface of the washer on which the lower surface of the bolt head is seated is formed into a mortar-shaped tapered surface. Is characterized by.

The invention of claim 3 is characterized in that a vertical split slit is formed on the peripheral wall of the washer so that the washer can be expanded and deformed.

The invention of claim 4 is characterized in that a vertical groove is formed on the outer peripheral surface of the washer so that the washer can be expanded and deformed.

According to a fifth aspect of the present invention, the bottom surface of the recess is formed into a mortar-shaped tapered surface, and the lower surface of the washer that abuts the bottom surface is formed into a substantially conical tapered surface.

The invention of claim 6 is characterized in that the slits are alternately formed in the upper and lower portions of the washer in the circumferential direction.

The invention of claim 7 is characterized in that substantially circular arc-shaped slits cut out from the lateral direction are formed in the peripheral wall of the washer, and the slits are formed alternately at the upper and lower positions of the washer peripheral wall. There is.

According to an eighth aspect of the present invention, there is provided a fixing structure for fixing a shaft and a fitted member fitted to the outer peripheral surface of the shaft through a shaft insertion hole, wherein a flat surface portion is provided at a predetermined position on the outer peripheral surface of the shaft. On the other hand, a flat portion is formed on the inner peripheral surface of the shaft insertion hole of the fitting member so as to abut the flat surface portion, and a bolt insertion hole is formed in a substantially vertical direction on the contact surface between the flat surface portion and the flat portion. In addition to being formed, the member to be fitted is fixed to the shaft by a bolt having the bolt insertion hole inserted therein.

The invention of claim 9 is characterized in that the inner surface of the shaft insertion hole of the member to be fitted is formed in a polygonal shape having the flat portion.

According to the invention of claims 1 to 7, when the member to be fitted is fixed to a predetermined position of the shaft, the bolt is inserted from the fitting insertion hole into the bolt insertion hole of the shaft, and the tip portion of the shaft portion of the bolt is inserted. When the screw is screwed into the female screw hole of the fitted member while being screwed, the lower surface of the bolt head gradually presses the mortar-shaped upper surface of the washer. Therefore, the washer is expanded and deformed through the slits or the vertical slits so that the outer peripheral surface of the washer comes into pressure contact with the inner peripheral surface of the fitting insertion hole of the member to be fitted and the bottom surface of the recess of the shaft. Therefore, in addition to the bolt axial force, the shaft and the fitted member can obtain a strong fixing action by pressure bonding between the bottom surface of the recess and the inner peripheral surface of the fitting insertion hole by the washer.

Further, according to the present invention, the shaft and the fitted member are not merely pressed and fixed by the axial force of the bolt, but the surface contact state between the flat portion and the flat portion is obtained. Since the bolts are tightened, the frictional force increases,
A stronger bond is obtained.

Further, since the torque fluctuations generated in the fitted member can be received by the abutting surfaces of the flat portion and the flat portion, the circumferential deviation between the fitted member and the shaft can be prevented.

[0025]

3 to 6 show an intake / exhaust valve drive control device for an internal combustion engine to which the shaft / fitted member fixing structure of the present invention is applied, and 21 in FIG. A drive shaft, which is a shaft to which a rotational force is transmitted from a crankshaft of a cylinder engine via a sprocket, is arranged at a peripheral portion of the drive shaft 21 with a certain clearance and has a center X of the drive shaft 21.
Is a cam shaft provided coaxially with and rotatable relative to the drive shaft 21.

The drive shaft 21 is extended in the front-rear direction of the engine and is formed in a hollow shape to reduce the weight. Further, as shown in FIG. 4, the drive shaft 21 has a uniform outer diameter from the one end 21a of the sprocket mounting portion 51 and the first journal 52 to the other end thereof, and the one end As shown in FIG. 2, four circular recesses 60 are formed at equidistant positions on the outer peripheral surface 21b from the 21a side to the other end side. This recess 60
Has a circular bottom surface 60a that is flat along the axial direction, and an inner peripheral surface 60b that is annular. further,
An insertion hole 61 for a bolt 62 is formed through the drive shaft 21 in the vertical direction (radial direction) from the center position of the bottom surface 60a of the recess 60.

The camshaft 22 is divided into four parts from the direction perpendicular to the axis for each cylinder at a predetermined position in the longitudinal direction, and the drive shaft 21 is inserted into an insertion hole 22a formed in the internal axial direction to drive the drive shaft. The shaft 21 is slidably supported on the outer peripheral surface 21c, and is rotatably supported by each one cam bearing 54 at the upper end of the cylinder head 7.
Further, as shown in FIG. 5, a plurality of cams 26 that open the two intake valves 23 per cylinder against the spring force of the valve spring 24 via the valve lifter 25 are integrally provided at predetermined positions on the outer periphery. It is provided.

A first flange portion 27 is integrally fixed to one end of each camshaft 22 on the one side, and the first flange portion 27 extends radially from the hollow portion as shown in FIG. An elongated rectangular first engaging groove 30 is formed along with, and a protruding surface 27a that slidably contacts one side surface of an annular disk 29 described later is provided integrally in the circumferential direction of the outer peripheral surface thereof. In addition, the camshaft 22 on the other side facing the first flange portion 27 with a constant gap.
The second flange portion 28 is arranged on the end side of the second flange portion.

Each of the second flange portions 28 has an insertion hole 32 on the inner peripheral surface thereof on the outer peripheral surface of the drive shaft 21 where each of the recesses 60 is formed.
Sleeve 32 which is a fitting member to be fitted and fixed via a
Are provided integrally. In addition, the second flange portion 28
As shown in FIG. 3, an elongated rectangular second engagement groove 33 is formed on the opposite side of the first engagement portion 30 of the first flange portion 27 in the radial direction, and the outer periphery thereof is A projection surface 28a that is in sliding contact with the other side surface of the annular disk 29 is formed on the surface.

As shown in FIGS. 1, 3 and 4, the sleeve 32 has a fitting insertion hole 63 into which the head 62a of the bolt 62 is fitted and arranged at a position corresponding to the recess 60 of the drive shaft 21 in the radial direction. In addition to being formed so as to penetrate therethrough, a female screw hole 63b into which a male screw portion 62c on the tip side of the shaft portion 62b of the bolt 62 is screwed is formed on the side opposite to the fitting insertion hole 63 in the radial direction. The fitting insertion hole 63 has a cylindrical shape, and the inner diameter thereof is slightly larger than the outer diameter of the bolt head portion 62a.

As shown in FIG. 2, in the bolt 62, a hexagonal groove 62d into which a hexagon wrench or the like is fitted is formed in the center of the outer end surface of a cylindrical head portion 62a, and a lower surface 62e of the head portion 62a is formed. It is formed into a substantially conical tapered surface.

Further, a washer 64 is interposed between the head portion 62a of the bolt 62 and the bottom surface 60a of the recess 60. As shown in FIGS. 1 and 2, this washer 64 has a substantially cylindrical shape and has an outer diameter of the fitting insertion hole 6 of the sleeve 32.
3, the inner diameter of the bolt hole 64a is set to be slightly larger than the outer diameter of the shaft portion 62b of the bolt 62. Further, the washer 64 has a slit 65 having a vertically split shape cut out in a part of the peripheral wall, and the upper surface 64b is formed into a mortar-shaped tapered surface. This taper angle is set to be substantially the same as the taper angle of the lower surface 62e of the bolt head 62a.

The annular disk 29 is interposed between the first flange portion 27 and the second flange portion 28, has a substantially donut plate shape as shown in FIG. 5, and has an inner diameter of the camshaft 2.
2 has an inner diameter substantially the same as the inner diameter of 2, and an annular gap S is formed between the outer peripheral surface of the drive shaft 21 and the outer peripheral portion 29a having a small width via the annular bearing 34. It is rotatably supported on the inner peripheral surface of the. In addition, the holding hole 29 formed at the opposite position on the diameter line.
b and 29c are provided with a pair of pins 36 and 37 that engage with the engagement grooves 30 and 33, respectively. These pins 36 and 3
7 project in opposite directions to each other in the axial direction of the camshaft, the base portion is rotatably supported in the holding holes 29b and 29c, and the engaging groove is formed on both side edges of the tip portion as shown in FIG. Opposed inner surfaces 30a, 30b, 33 of 30, 33
a and 33b abutting flat surface portions 36a and 36
b, 37a, 37b are formed.

The disk housing 35 has a substantially annular shape as shown in FIGS. 3 to 5, and has a boss portion 35a at one end of the outer periphery and a pivot pin 3 penetrating the boss portion 35a.
8 is provided so as to be vertically swingable in FIG. 5, while the lever portion 35 is provided on the outer peripheral surface opposite to the boss portion 35a.
b protrudes along the radial direction. The disc housing 35 is configured to swing by a drive mechanism 39 via a lever 35b.

As shown in FIGS. 5 and 6, the drive mechanism 39 includes first and second cylinders 40 and 41 formed to face predetermined portions of the cylinder head, and the respective cylinders 40 and 41.
A hydraulic piston 42 and a plunger 43 which are provided so as to be able to protrude and retract from the inside and hold the arc-shaped tip of the lever portion 35b at each tip edge from above and below;
And a hydraulic circuit 44 for supplying and discharging the hydraulic pressure to and from the pressure receiving chamber 40a in the inside to move the hydraulic piston 42 forward and backward.

The plunger 43 provided in the second cylinder 41 is formed in a substantially cylindrical shape with a bottom, and the spring force of the coil spring 45 elastically mounted in the second cylinder 41 causes the plunger 43 to advance (toward the lever portion). Is urged by.

The hydraulic circuit 44 has an oil passage 47 having one end communicating with the oil pan 46 and the other end communicating with the pressure receiving chamber 40a, and an oil pump 48 provided on the oil pan 46 side of the oil passage 47. And a 3-port 2-position electromagnetic switching valve 49 provided on the downstream side of the oil pump 48. The electromagnetic switching valve 49 switches the flow passage by an ON-OFF signal from the controller 50 that detects the current engine operating state based on signals such as the engine speed and the intake air amount, and the oil passage 47 is activated by the ON signal. While communicating with the whole, the oil passage 4 by the OFF signal
7 and the drain passage 55 are communicated with each other.

The operation of this embodiment will be described below.
That is, at the time of high engine speed, when an ON signal is output from the controller 50 that has detected such an operating state to the electromagnetic switching valve 49, the hydraulic oil pumped from the oil pump 48 to the oil passage 47 is directly supplied to the pressure receiving chamber 40a. It Therefore, as the internal pressure of the pressure receiving chamber 40a increases, the hydraulic piston 42 pushes down the lever portion 35b against the spring force of the coil spring 45 as shown by the solid line in FIGS. The rotation center Y of 29 and the center X of the drive shaft 21 coincide. In this case, no rotational phase is generated between the annular disc 29 and the drive shaft 21, and the center of the camshaft 22 and the annular disc 2 are not rotated.
Since the center Y of 9 is also coincident, there is no difference in rotational phase between the two 22 and 29. Therefore, the sleeve 32 rotates in synchronization with the rotation of the drive shaft 21, and the engagement groove 33, the pin 37, and the annular disc 2 on the second flange portion 28 side are also rotated.
The camshaft 22 also rotates synchronously via the pin 9, the pin 36, and the engagement groove 30 on the side of the first flange portion 27. Therefore, the intake valve 23 has a large valve operating angle, and the valve closing timing is sufficiently delayed. As a result, the intake charging efficiency is improved, and a high output torque is obtained.

On the other hand, when the engine speed is low, the controller 5
From 0, an OFF signal is output to the electromagnetic switching valve 49 to shut off the upstream side of the oil passage 47 and communicate the downstream side of the oil passage 47 with the drain passage 55. For this reason, the pressure receiving chamber 40a
Hydraulic oil inside flows back through the oil passage 47 and is returned from the drain passage 55 into the oil pan 46.
The hydraulic piston 42 moves backward through the plunger 43 by the spring force of the coil spring 45 as the internal pressure of a decreases. As a result, the disc housing 35 is pushed up by the plunger 43 and swings upward with the pivot pin 38 as a fulcrum, as shown by the dashed line in FIGS. Eccentric with center X. Therefore, the locking groove 33 and the pin 37 of the second flange portion 28, and the locking groove 30 and the pin 3 of the first flange portion 27.
The sliding position with 6 reciprocates for each rotation of the drive shaft 21,
The angular velocity of the annular disk 29 is changed to rotate at an unequal angular velocity. Therefore, the intake valve 23 has a small valve operating angle (valve timing) while the valve lift characteristic thereof remains constant and the valve closing timing is sufficiently advanced. Therefore, the intake charging efficiency is improved and the low-speed torque is improved.

In this embodiment, in order to fix each second flange portion 28 of the drive shaft 21 to a predetermined position, first the sleeve 32 of each second flange portion 28 is sequentially attached to the drive shaft 21 from the one end 21a. It is inserted and fitted by clearance fitting, and the fitting insertion hole 63 of the sleeve 32 is inserted into the bolt insertion hole 6 of the drive shaft 21.
Match 1. After that, the bolt 62 having the washer 64 assembled on the head portion 62a side is inserted into the fitting insertion hole 63 and the bolt insertion hole 61, and the hexagon wrench (not shown) is used to rotate the bolt head portion 62a while the male screw portion 62c and the female screw portion 62c. Hole 6
3b is screwed and screwed in. Accordingly, as shown in FIGS. 1 and 4, the tapered lower surface 62 of the bolt head 62a is
e gradually presses the tapered upper surface 64b of the washer 64, whereby the washer 64 gradually expands in diameter through the slit 65, and the outer peripheral surface 64c of the washer 64 is pressed against the inner peripheral surface 63a of the fitting hole 63. At the same time, the bolt 62 is fastened with a predetermined axial force. This allows the sleeve 32
Is firmly and reliably fixed to the drive shaft 21, and the torque fluctuation transmitted from the cam shaft 22 to the sleeve 32 can be tightly supported by the drive shaft 21.

That is, in addition to the bolt axial force, the pressure contact force to the washer 64 on the lower surface 62e of the bolt head 62a and the inner peripheral surface 63a of the fitting insertion hole 63 of the outer peripheral surface 64c of the washer 64.
Since the pressing force against the sleeve 32 acts on the drive shaft 21, the sleeve 32 can be firmly and reliably fixed to the drive shaft 21 and tightly locked due to the close contact of the respective parts.

Moreover, the shaft portion 62b of the bolt 62 and the head portion 6
Since the drive shaft 21 or the sleeve 32 is not directly supported by the 2a but is supported via the washer 64, the occurrence of bending stress of the bolt 62 is suppressed, and the occurrence of cracking or damage of the bolt 62 due to the bending stress. It can be prevented.

Further, in the present embodiment, since the second flange portions 28 are fixed to the drive shaft 21 by the above-described structure and procedure, the outer diameter of the drive shaft 21 is formed in a tapered shape as in the conventional case. Without doing so, it is possible to set a relatively large uniform diameter. Therefore, it is possible to prevent the torsional rigidity of the drive shaft 21 from being lowered, the valve timing control accuracy from being lowered, and the irregular movement of the intake valve 23 to be prevented.

Further, since the outer diameter of the drive shaft 21 can be made uniform, each second flange portion 28 and each camshaft 2 can be made.
Since the inner diameters of 2 can be made uniform, the drive shaft 2
Since the second flange portion 28 and the camshaft 21 can be used in common not only in the manufacturing work of the 1 itself, the manufacturing work efficiency can be improved and the cost can be greatly reduced.

Further, by making the outer diameter of the drive shaft 21 uniform, it is easy to obtain the accuracy of the diameter and straightness of the entire outer peripheral surface, and the camshaft 22 of each cylinder is stable at any position of the entire length of the drive shaft 21. It becomes possible to support it. As a result, the camshaft 22 can be prevented from falling down, so that one cam bearing 54 that supports one camshaft 22 from the outside can be provided. Therefore, the manufacturing workability can be improved and the cost can be reduced by reducing the number of parts.

Further, as described above, since the straight drive shaft 21 is bored and counterbored, and the sleeve 32 is easily bored and threaded, each of which can be formed coaxially. These molding processes become extremely easy, the processing cost can be reduced, and the processing equipment can be downsized. Incidentally, if the washer 64 is also integrally formed by, for example, a sintering method, the manufacturing becomes easier.

Further, as described above, the accuracy of the recess 60 bottom surface 60a of the drive shaft 21, the female screw hole 64 of the sleeve 32, and the inner and outer peripheral surfaces of the washer 64 is easily obtained due to the easiness of the working operation, and the sleeve 32 with respect to the drive shaft 21 can be precisely manufactured. The mounting position accuracy is easy to obtain.

Further, although the outer peripheral surface 21b of the drive shaft 21 and the inner peripheral surface of the insertion hole 32a of the sleeve 32 are fitted by a clearance fit which is easy to assemble, even if there is a clearance due to the clearance fitting, the drive shaft 21 is driven by the axial force of the bolt. The drive shaft 21 is deformed by the compression action and the outer peripheral surface 21b comes into close contact with the inner peripheral surface of the insertion hole 32a of the sleeve 32, so that a tight fixing without play becomes possible.

7 and 8 show a second embodiment of the present invention, in which the fixing structure is applied to the camshaft 22 and the cam 26 of a normal DOHC type internal combustion engine.

That is, a recess 60 having a flat bottom surface 60a is formed at a predetermined position on the outer peripheral surface of the camshaft 22, and a bolt insertion hole 61 is formed in the peripheral wall opposite to the recess 60.
Are formed through. On the other hand, in the cam 26, a cam shaft insertion hole 26c is formed in the center of the base circle portion 26a, and a fitting insertion hole 6 into which the head portion 62a of the bolt 62 is inserted and inserted in the center position of the outer peripheral surface of the base circle portion 26a.
3 are formed. Further, a female screw hole 63a coaxial with the fitting insertion hole 63 is cut inside the cam lift portion 26b.

In the bolt 62, as in the first embodiment, the lower surface 62e of the head portion 62a is formed into a substantially conical tapered surface, and the washer 64 is interposed between the head portion 62a and the recess bottom surface 60a. It is equipped. Similar to the first embodiment, the washer 64 has an upper surface 64b formed into a mortar-shaped tapered surface, and a longitudinal split slit (not shown) is formed in a part of the peripheral wall.

Therefore, also in this embodiment, the same operational effect as in the first embodiment can be obtained, and since the entire outer diameter of the camshaft 22 can be formed uniformly and relatively large, the torsional rigidity can be improved.

FIGS. 9 to 11 show a third embodiment of the present invention. In this embodiment, like the first embodiment, the present invention is applied to the drive shaft 21 and the second flange portion 28 of the intake / exhaust valve drive control device. What is different is the bottom surface 6 of the recess 60 of the drive shaft 21.
0a is formed into a mortar-shaped tapered surface, while the bottom surface 60a
The lower surface 64d of the washer 64 that abuts against is formed into a substantially conical tapered surface.

Therefore, according to this embodiment, when the bolt 62 is tightened when the second flange portion 28 is fixed, the washer 64 is expanded and deformed on the upper side as shown by the broken line in FIG. Is the inner peripheral surface 63 of the insertion hole 63
While being pressed against a, the lower side is displaced along the tapered surface of the bottom surface 60a of the recess to be reduced in diameter and deformed, and the lower inner peripheral surface is pressed against the outer peripheral surface of the shaft portion 62b of the bolt 62.

Therefore, the bolt 62, the sleeve 32, and the drive shaft 21 are tightly locked by the expansion / contraction deformation of the washer 64 due to the axial force of the bolt 62. This provides a strong and secure bond.

In addition to forming one slit 65 as described above, the washer 64 may be a vertical groove slit 66 instead of the vertical slit shape as shown in FIG. Further, as shown in FIG. 13A, vertical slit-like short slits 67a, 67b may be formed intermittently alternately in the circumferential direction on the upper side and the lower side. FIG.
If it is formed as shown in A, the washer 64 can be easily expanded and deformed, so that the washer 64 can be uniformly expanded and deformed.
The pressure contact force of No. 3 with respect to the inner peripheral surface 63a increases.

A similar method is possible with the structure shown in FIG. 13B. That is, the structure shown in FIG. 13B is
The entire washer 64 is formed in a taper shape from the upper end to the lower end on the inner peripheral surface of the washer 64, and the semi-arcuate slit 6 is cut out in the shape of a ring from the lateral direction at the upper and lower positions of the peripheral wall of the washer 64.
7c and 67d are alternately formed on the upper and lower sides. Even with this structure, it is possible to facilitate uniform diameter expansion deformation of the entire washer 64.

14 to 16 show a fourth embodiment of the present invention in which the drive shaft 21 is provided with the second flange portion 3 without using a washer.
2 is fixed.

That is, a recess 68 along the axial direction is formed at a predetermined position on the outer peripheral surface of the drive shaft 21, and a flat concave shape on which the head 69a of the bolt 69 is seated is formed on the outer peripheral surface opposite to the recess 68. Seating surface 70 is formed. In addition, a bolt insertion hole 71 that penetrates from the center of the seating surface 70 to the recess 68 is formed. The concave portion 68 has a flat bottom surface 68a.

On the other hand, the second flange portion 28 is provided so as to project from the outer peripheral edge of the front end portion of the sleeve 32, and the sleeve 3
In No. 2, the insertion hole 32a of the drive shaft 21 is formed in the inner axial direction, and the insertion hole 72 into which the head portion 69a of the bolt 69 is inserted is formed in the peripheral wall on the side substantially opposite to the second flange portion 28. Also, the fitting insertion hole 7 is formed in the peripheral wall on the side opposite to the fitting insertion hole 72.
A female screw hole 73 coaxial with 2 is formed therethrough. Further, the drive shaft insertion hole 32a is formed into a substantially U-shaped cross section, and an inner surface 32b, which is a flat surface portion on the female screw hole 73 side with which the bottom surface 68a of the recess 68 of the drive shaft 21 abuts, is formed flat. In addition, the width W between the inner surfaces 32d, 32d
The drive shaft 21 has a diameter slightly larger than the outer diameter d so that a clearance fit can be made. Also, the inner surface 32
The inner diameter from b to the arcuate facing surface 32c is equal to the drive shaft 21.
The outer diameter of the drive shaft is set to be sufficiently larger than the outer diameter of
The gap S1 with respect to c is set to be larger than the thickness S2 between the recess bottom surface 68a and the outer peripheral surface 21b.

Therefore, in order to fix the sleeve 32 to the drive shaft 21, first, the sleeve 32 is inserted into the drive shaft insertion hole 32.
The drive shaft 21 is fitted from one end side through a, the flat inner surface 32b of the insertion hole 32a is placed in contact with the recess bottom surface 68a, and the holes are aligned. Next, the bolt 69 is inserted into the insertion hole 71 from the side of the fitting insertion hole 72, and the male screw portion 69c on the tip side of the shaft portion 68b is screwed into the female screw hole 73 and tightened with a predetermined axial torque. As a result, the flat inner surface 32b of the sleeve 32 and the bottom surface 68a of the recess of the drive shaft 21 are formed.
Since they are pressed into contact with each other in a surface contact state, the frictional resistance increases and a firm and reliable fixing action can be obtained.

Further, since the rotational torque fluctuation generated in the drive shaft 21 can be received by the contact surface between the inner surface 32b and the bottom surface 68a, the circumferential deviation between the drive shaft 21 and the sleeve 32 can be prevented.

Further, both inner side surfaces 32d of the insertion hole 32a,
Since the gap between the width W between 32d and the outer diameter d of the drive shaft is reduced to be in a close contact state, the radial runout of the second flange portion 28 with respect to the drive shaft 21 can be restricted.

Further, as described above, the drive shaft outer peripheral surface 21b
Since the gap S1 between the opposed surface 32c and the opposing surface 32c is set to be larger than the thickness S2 between the recess bottom surface 68a and the outer peripheral surface 21b, the assembling property of the second flange portion 28 to the drive shaft 21 becomes good.

17 to 20 show a fifth embodiment of the present invention, in which the bottom surface 68a of the recess 68 of the drive shaft 21 is cut out in a substantially eight-shaped cross section as shown in FIG. The drive shaft insertion hole 32a is formed in a substantially pentagonal cross section as shown in FIG. And the bottom surface 6
The upper inner surface 32b of the drive shaft insertion hole 32a, which abuts on the drive shaft 8a, is formed in an octagonal shape that is the same as the bottom surface 68a. The other structure is similar to that of the fourth embodiment.

Therefore, according to this embodiment, since the contact area between the bottom surface 68a and the inner surface 32b becomes large,
Further, a firm and stable fixing action can be obtained. FIG. 18B schematically shows the side force Fs in which the axial force W of the bolt 69 acts on the bottom surface 68a. In this case, the tightening force Fs other than the axial force W acts on the inner surface 32b as a side force, so that a stronger fixing action can be obtained.

The present invention is not limited to the configuration of the above-described embodiment. For example, the washer 64 may be formed of a flexible deformable alloy or the like, or the washer 64 may be expanded depending on the thickness of the washer in the radial direction, the material selected, and the like. Since it is possible to obtain the effects of diameter and diameter reduction, it is not necessary to form a slit or the like.

[0068]

As is apparent from the above description, according to the fixing structure of the present invention, since the outer diameter of the shaft can be made uniform, it is of course possible to prevent the deterioration of torsional rigidity and the like. To fix the fitted member to the shaft, when the bolt is tightened, the washer expands and deforms, and the outer peripheral surface is pressed against the inner peripheral surface of the fitting insertion hole of the fitted member. Therefore, in addition to the axial force of the bolt, the shaft and the fitted member can obtain a strong and reliable fixing force by the pressure contact force of the washer, and the backlash of each portion can be prevented by the pressure contact of the washer, so that a tight fixing state can be obtained.

Further, instead of being fixed by bulge lowering as in the conventional case, it is fixed by bolts using spot facing or boring, so that the whole forming process becomes extremely easy and large processing equipment is not required. Become.

Further, according to the invention of claim 5, the upper side of the washer is expanded and deformed by the tightening of the bolt, and the lower side is contracted and deformed, and the inner peripheral surface of the fitting hole and the shaft portion of the bolt are respectively deformed. Since the pressure is applied to the outer peripheral surface, tighter and firmer fixing of the bolt to the fitted member and the shaft can be obtained.

Further, according to the inventions of claims 8 and 9, the frictional force is increased due to the surface contact between the flat surface portion and the flat portion to firmly fix the member to be fitted and, for example, the shaft due to the fluctuation of the rotating torque. It is possible to prevent the occurrence of displacement in the circumferential direction between the fitting member and the fitted member.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a drive shaft, bolts and washers used in this embodiment.

FIG. 3 is a sectional view of an essential part of an intake / exhaust valve drive control device to which the present embodiment is applied.

FIG. 4 is a plan view of the device.

FIG. 5 is a sectional view taken along line AA of FIG. 4;

FIG. 6 is a schematic view showing a drive mechanism of the apparatus.

FIG. 7 is a sectional view taken along line BB in FIG. 8 showing a second embodiment of the present invention.

FIG. 8 is a vertical cross-sectional view of a main part showing a second embodiment.

9 is a sectional view taken along line CC of FIG. 10 showing the third embodiment of the present invention.

FIG. 10 is a vertical cross-sectional view of a main part showing a third embodiment.

FIG. 11 is an enlarged sectional view of an essential part showing the operation of the present embodiment.

FIG. 12 is a perspective view showing another example of a washer used in each embodiment.

FIG. 13A is a perspective view showing still another example of the washer, and B is a perspective view showing still another example of the washer. .

FIG. 14 is a longitudinal sectional view of a main part showing a fourth embodiment of the present invention.

FIG. 15 is a sectional view taken along line DD of FIG. 14;

FIG. 16 is a plan view of a main part of the present embodiment.

FIG. 17 is a vertical cross-sectional view of a main part showing a fifth embodiment of the present invention.

18A is a cross-sectional view taken along line EE of FIG. 17, and B is an explanatory view showing a side force acting on the bottom surface of the concave portion of the bolt axial force in the present embodiment.

FIG. 19 is a plan view of a main part of this embodiment.

FIG. 20 is a perspective view showing a shaft used in this embodiment.

FIG. 21 is a sectional view showing a fixing structure of a conventional drive shaft and a second flange portion applied to an intake / exhaust valve drive control device.

FIG. 22 is a vertical cross-sectional view of the main part of the same device.

[Explanation of symbols]

 21 ... Drive shaft (shaft) 22 ... Cam shaft (shaft) 32 ... Sleeve (fitting member) 32a ... Drive shaft insertion hole 32b ... Inner surface (flat portion) 60 ... Concave portion 60a ... Bottom surface 61 ... Bolt insertion hole 62 ... Bolt 62a ... head portion 62e ... lower surface 63 ... insertion hole 64 ... washer 64b ... upper surface 64d ... lower surface 65, 66, 67a, 67b ... slit 68 ... recessed portion 68a ... bottom surface (flat surface portion) 69 ... bolt 73 ... bolt insertion hole

Claims (9)

[Claims] 1. A fixing structure for fixing a shaft and a fitting member fitted on the outer peripheral surface of the shaft via a shaft insertion hole, wherein a recess is formed at a predetermined position on the outer peripheral surface of the shaft, and While forming a bolt insertion hole through the radial direction from the vertical direction to the flat bottom surface of the recess, while forming a fitting insertion hole for the bolt head is inserted into the peripheral wall of the fitted member corresponding to the recess, Further, a washer-fixing structure for a shaft and a fitting member, characterized in that a washer which is expanded and deformed according to an axial force of the bolt is interposed between the bolt head and the bottom surface of the recess. 2. The lower surface of the bolt head is formed into a substantially conical tapered surface, while the upper surface of the washer on which the lower surface of the bolt head is seated is formed into a mortar-shaped tapered surface. The structure for fixing the shaft and the fitted member according to Item 1. 3. The fixing structure for a shaft and a fitting member according to claim 1, wherein a slit in a vertical split shape is formed on a peripheral wall of the washer so that the washer can be expanded and deformed. 4. The fixing structure for a shaft and a fitting member according to claim 1, wherein a vertical groove is formed on an outer peripheral surface of the washer so that the washer can be expanded and deformed. 5. The bottom surface of the recess is formed into a mortar-shaped tapered surface, and the lower surface of the washer that abuts the bottom surface is formed into a substantially conical tapered surface. Structure of fixed member of shaft. 6. The fixing structure for a member to be fitted to a shaft according to claim 1, wherein the slits are formed in the upper and lower portions of the washer alternately in the circumferential direction. 7. The washer has a peripheral wall formed with slits of a substantially semi-circular shape cut out from the lateral direction, and the slits are alternately formed at upper and lower positions of the washer peripheral wall. The structure for fixing the shaft and the fitted member according to 2 or 5. 8. A fixing structure for fixing a shaft and a fitting member fitted on the outer peripheral surface of the shaft through a shaft insertion hole, wherein a flat surface portion is formed at a predetermined position on the outer peripheral surface of the shaft, A flat portion is formed on the inner peripheral surface of the shaft insertion hole of the fitted member so as to abut the flat portion, and a bolt insertion hole is formed in a substantially vertical direction on the contact surface between the flat portion and the flat portion,
A fixing structure for a shaft and a member to be fitted, wherein a member to be fitted is fixed to a shaft by a bolt inserted into the bolt insertion hole. 9. The fixing structure for a member to be fitted to a shaft according to claim 8, wherein an inner surface shape of the shaft insertion hole of the member to be fitted is formed into a polygonal shape having the flat portion.