JPH11141311A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce number of component items, a manufacturing cost, and weight of a device. SOLUTION: A valve timing is variably controlled through conversion of relative rotational phases of a timing sprocket 21 and a cam shaft 22, by axially moving a cylindrical gear 39 arranged between the sprocket 21 and the shaft 22, by the use of hydraulic pressure relatively supplied to and discharged from pressure receiving chambers 44, 45 through a hydraulic circuit 47. A passage portion 51 composing a first oil passage 49 of the hydraulic circuit 47 is formed in a shaft 35 and a columnar part 36, other than a head 33 of a fixation bolt 30. An outer surface of the head 33 is brought into close contact with an inner surface of a through-hole 34, while a seal ring 38 is fitted to a seal groove 37 of an outer peripheral surface of the head 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing control device for variably controlling the opening and closing timing of intake and exhaust valves according to the operating state of an internal combustion engine.

[0002]

2. Description of the Related Art Various types of conventional valve timing control devices of this type have been provided, and one example thereof is described in Japanese Utility Model Application Laid-Open No. 6-83909 filed earlier by the present applicant.

[0004] Referring to FIG. 4, a schematic description will be given. A cylindrical timing pulley 1 is driven to rotate by a crankshaft of an engine via a timing belt, and a fixing bolt 7 is provided at one end.
A camshaft 2 having a sleeve 3 fixed within the timing pulley 1 and having a cam for opening and closing an intake / exhaust valve on the outer periphery, and a helical internal / external tooth 4
a and 4b are the inner teeth of the timing pulley 1 and the sleeve 3
A cylindrical gear 4 that is movable in the axial direction of the camshaft while meshing with the outer teeth of the hydraulic motor, a hydraulic circuit 5 and a compression spring 6 that move the cylindrical gear 4 in the axial direction according to the operating state of the engine.
And The timing pulley 1 is provided with a seal cap 10 which is screwed into a working hole 8 formed in the center of a front cover 1a caulked and fixed to the front end side to seal the inside of the oil chamber 9.

Further, the cylindrical gear 4 is provided with a hydraulic pressure supplied from an oil passage 5a and a passage hole 5b of the hydraulic circuit 5 to a pressure chamber 11 formed between a front end portion and a front cover 1a, and a compression coil spring. By the spring force of No. 6, it moves while rotating in the front-rear direction.

That is, for example, when the engine is under a low load, the three-way electromagnetic switching valve 12 included in the hydraulic circuit 5 is turned off,
The oil pressure in the pressure chamber 11 is discharged to the outside through the oil passage 5a and the passage hole 5b to lower the pressure in the pressure chamber 11 to a low pressure. As a result, the cylindrical gear 4 moves to the maximum forward position by the spring force of the compression spring 6, and changes the relative rotation phase between the timing pulley 1 and the camshaft 2 to one side. The closing timing is retarded.

On the other hand, when the engine is under a high load, the electromagnetic switching valve 12
Is supplied to the pressure chamber 11 through the oil chamber 9 from the oil passage 5a and the passage hole 5b of the hydraulic circuit 5, and the internal pressure of the pressure chamber 11 rises. by this,
The cylindrical gear 4 moves to the maximum rear position against the spring force of the compression spring 6, converts the relative rotational phase of the timing pulley 1 and the camshaft 2 to the other side, and advances the closing timing of the intake valve. The angle is controlled.

[0007]

However, in the conventional valve timing control device, the hydraulic circuit 5
The passage hole 5b, which is a part of the fixing bolt 7, is formed so as to penetrate in the axial direction inside the fixing bolt 7, and the head 7 of the fixing bolt 7
An oil chamber 9 communicating with the oil passage 5a is formed outside the line a. Therefore, in order to seal the oil chamber 9, a seal cap 10 must be attached to the center of the front cover 1a. For this reason, not only is the number of parts inevitably increased, but also the manufacturing workability is deteriorated, and the weight of the entire apparatus is increased.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the actual situation of the conventional valve timing control device, and the invention according to claim 1 has a rotating body driven by an engine and a rotating body. A camshaft having a cam for operating an intake / exhaust valve by a rotating force transmitted from the rotating body, a sleeve fixed to one end of the camshaft by a fixing bolt in an axial direction and inserted through the rotating body; A valve timing control device that is interposed between the rotating body and the rotating body and that is operated by hydraulic pressure of a hydraulic circuit to convert a relative rotation phase between the rotating body and the camshaft. A part of the oil passage of the circuit is formed at a portion excluding the head of the fixing bolt, and a bolt insertion hole is formed in the inner axial direction of the sleeve, and the bolt insertion hole is formed. An insertion hole into which the head of the fixing bolt is inserted is formed on the outer end side, and when the sleeve is fixed to the camshaft by the fixing bolt, the outer surface of the head of the fixing bolt and the inner peripheral surface of the insertion hole and It is characterized in that it is tightly sealed with the bottom surface.

According to a second aspect of the present invention, a seal ring is provided between the outer peripheral surface of the head of the fixing bolt and the inner peripheral surface of the fitting hole.

According to a third aspect of the present invention, a part of the oil passage is formed radially on a cylindrical portion provided between the shaft portion and the head portion in the axial direction of the shaft portion of the fixing bolt. It is characterized by.

According to a fourth aspect of the present invention, a part of the oil passage is formed inside the sleeve, and between the bottom surface of the insertion hole and the inner end surface of the head of the fixing bolt facing the bottom surface. It is characterized by providing a seal ring.

The invention according to claim 5 is characterized in that the phase conversion means is operated in the camshaft axial direction by front and rear oil pressure.

According to the present invention, a part of the oil passage is not formed in the inner axial direction including the head of the fixing bolt as in the related art, but is formed only in the shaft or the column excluding the head. This eliminates the need for a front cover seal cap. Moreover, the oil pressure leaked from between the bolt insertion hole of the sleeve and the fixing bolt is prevented from leaking to the outside by the close sealing surface between the head of the fixing bolt and the inner surface of the insertion hole of the sleeve or a seal ring. .

[0014]

FIG. 1 shows a first embodiment of a valve timing control apparatus according to the present invention. In FIG. 1, reference numeral 21 denotes a timing sprocket which is a rotating body driven to rotate by a crankshaft of an engine via a timing chain. Reference numeral 22 denotes a camshaft having a cam on its outer periphery for opening and closing the intake valve by the rotational force transmitted from the timing sprocket 21. The timing sprocket 21 is provided with a sealing member 25 at the front end of a cylindrical body 23 having a stepped diameter. , A front cover 24 is rotatably provided, and inner teeth 23 a are formed on the front end side of the inner peripheral surface of the cylindrical main body 23.

The camshaft 22 is rotatably supported by a cam bearing groove at the upper end of a cylinder head 27 and a cam bracket 28, and a sleeve 29 housed in the cylindrical main body 23 at one end is fixed by a fixing bolt 30. It is fixed from the axial direction. The sleeve 29 has a rear end large diameter portion 29b that rotatably supports the rear end inner periphery of the cylindrical main body 23.
And a small diameter portion 29c to which the front cover 24 is caulked and fixed.
The large-diameter portion 29b is positioned in the circumferential direction on the camshaft 22 by the positioning pin 31, and the outer teeth 2 are attached to the front end of the outer peripheral surface of the small-diameter portion 29c.
9a are formed.

A female screw hole 22 formed in the inner axial direction of the camshaft 22 is formed in the inner axial direction of the sleeve 29.
The bolt insertion hole 32 which is continuous with the hole a is formed at the outer end of the bolt insertion hole 32 on the front cover 24 side.
4 is drilled to a depth substantially at the center of the small diameter portion 29c in the axial direction.

On the other hand, as shown in FIG. 2, the fixing bolt 30 has a head 33 formed in a cylindrical shape having a diameter slightly smaller than the inner diameter of the fitting hole 34, and an outer peripheral surface 33 a formed in the fitting hole 34. The female screw hole 22a is formed so as to be in close contact with the peripheral surface 34a, and is provided at the end of the shaft portion 35 inserted through the bolt insertion hole 32.
Is formed with a male screw 35a that is screwed into the screw. A cylindrical portion 36 having an outer shape slightly smaller than the outer diameter of the head portion 33 is integrally formed between the head portion 33 and the shaft 35, and the inner end surface 36a of the cylindrical portion 36 and the fitting hole 34 are formed. Bottom surface 34b is in close contact. In the fixing bolt 30, a passage hole 5 which constitutes a part of a first oil passage 49 of a hydraulic circuit 47 described later is provided.
1 is formed. That is, the passage hole 51 is formed continuously in the inner axial direction of the shaft portion 35 except for the head portion 33 and in the inner radial direction of the cylindrical portion 36. Further, a seal ring 38 is fitted and fixed in an annular seal groove 37 formed in an outer peripheral surface 33 a of a head 33 of the fixing bolt 30, and an outer peripheral surface of the seal ring 38 The sealing function is exerted by pressure bonding to the surface 34a.

A cylindrical gear 39 which is movable in the axial direction of the camshaft 22 is interposed between the cylindrical main body 23 and the sleeve 29. The cylindrical gear 39 includes front and rear gear components 39a, 39 divided into two parts from a direction perpendicular to the axis.
The two gear components 39a and 39b are connected by a connecting pin 40 and a coil spring 41 while being urged in a direction approaching each other, and have the inner teeth 23a and the outer teeth on the inner and outer peripheral surfaces. Helical internal and external teeth 39c and 39d spirally meshed with the outer teeth 29a are formed. In addition, in the cylindrical gear 39, the maximum forward (leftward in the figure) movement position is regulated at a position where the front gear component 39a abuts on the inner end surface of the front cover 24, while the rear gear component 39b is restricted. The maximum rearward (rightward direction in the figure) movement position is restricted at a position where the flange portion 42 provided at the rear end of the rear end abuts against the stopper ring 43 fixed to the inner peripheral surface of the cylindrical main body 23. I have. A coil spring 26 having a small spring force for urging the cylindrical gear 39 to the maximum forward position while the engine is stopped is elastically mounted between the rear gear portion 39b and the large diameter portion 29a of the sleeve 29. ing.

The flange portion 42 is provided on the cylindrical main body 2.
The first pressure receiving chamber 44 is defined in cooperation with the stepped portion 3, and the second pressure receiving chamber 45 is defined between the rear surface and the large diameter portion 29 b of the sleeve 29. A seal ring 46 for sealing between the pressure receiving chambers 44 and 45 is fitted and fixed to the outer periphery of the flange portion 42.

Further, the cylindrical gear 39 is moved in the axial direction (front-back direction) by a drive mechanism. The drive mechanism has a hydraulic circuit 47 for relatively supplying and discharging hydraulic pressure to the first pressure receiving chamber 44 and the second pressure receiving chamber 45, and an electromagnetic switching valve 48 provided in the middle of the hydraulic circuit 47. ing.

The hydraulic circuit 47 includes a first oil passage 49 for supplying and discharging hydraulic pressure to and from the first pressure receiving chamber 44, and a second oil passage 50 for supplying and discharging hydraulic pressure to and from the second pressure receiving chamber 45. The first oil passage 49 is provided between the cylinder head 27 and the camshaft 22.
Extending from the radial direction to the axial direction, and further including the passage hole 51 and an annular groove 52 formed on the outer peripheral surface of the cylindrical portion 36.
And Further, the bolt cylindrical portion 3 of the sleeve 29
In the peripheral wall near 6, four first through holes 53 communicating with the annular groove 52 are formed to penetrate in the cross diametrical direction, and the first through holes 53 are formed in annular grooves 54 formed on the outer periphery thereof. Through the first pressure receiving chamber 44.

On the other hand, the second oil passage 50 is formed by bending the cylinder head 27 and one side in the axial direction of the camshaft 22 and inside the sleeve 29 into an L-shape.
9 and communicates with the second pressure receiving chamber 45.

The electromagnetic switching valve 48 is an ordinary four-port two
It is of a position type, in which a solenoid, a passage component, a spool valve and the like are housed, a drain passage 56 communicating with an oil pan 55 is connected, and an oil main gallery is connected to an oil pump 57. 58. Also, this electromagnetic switching valve 48
The switching is controlled by a controller 59 that detects the engine operating state. That is, the oil main gallery 58 communicates with the first oil passage 49 or the second oil passage 50 according to the engine speed and the load, and the second oil passage 50 or the first oil passage 49 communicates with the drain passage 56 as appropriate. Control to be performed. In a predetermined rotation range such as a middle rotation, each of the oil passages 49,
By controlling the opening amount such as 50, the hydraulic pressure supply / discharge amount of each pressure receiving chamber 44, 45 is appropriately adjusted.

Therefore, according to this embodiment, for example, in the low-speed low-load range after the engine is started, the controller 5
9 outputs a control signal to the electromagnetic switching valve 48 to operate it, thereby connecting the oil main gallery 58 to the second oil passage 50 and, at the same time, connecting the first oil passage 49 to the drain passage 56.
Therefore, the flange portion 42 is pressed leftward by the high oil pressure supplied to the second pressure receiving chamber 45 as shown in FIG. 1, and holds the entire cylindrical gear 39 at the maximum leftward (forward) position. . For this reason, the relative rotation phase between the timing sprocket 21 and the camshaft 22 is maintained in a state of being converted to one side via each tooth, and the closing timing of the intake valve is retarded.

When the engine shifts from the low-speed low-load range to the high-speed high-load range, the oil main gallery 58 communicates with the first oil passage 49 by the electromagnetic switching valve 48, and the second oil passage 50 And the drain passage 56 communicate with each other. Therefore, the oil pressure in the second pressure receiving chamber 45 is returned to the oil pan 55 through the drain passage 56 via the second oil passage 50, while the high oil pressure flowing into the first oil passage 49 is reduced by the passage hole 51, the annular shape. The first pressure receiving chamber 4 passes through the groove 52, the through hole 53, and the annular groove 54.
4, the pressure in the first pressure receiving chamber 44 becomes high. Therefore, the cylindrical gear 39 moves rightward (rearward) until the flange portion 42 of the rear gear component 39b abuts against the stopper ring 43. Therefore, the relative rotation phase between the timing sprocket 21 and the camshaft 22 is converted to the other side, and the closing timing of the intake valve is advanced.

According to this embodiment, a part of the first oil passage 49 is constituted by the passage hole 51 instead of the conventional oil chamber, and the outer peripheral surface 33a of the bolt head 33 and the insertion hole 34 are formed. Inner peripheral surface 34a and inner end surface 36 of cylindrical portion 36
a and the bottom surface 34b of the fitting hole 34 and the seal ring 38 between the peripheral surfaces 33a, 34a provides double sealing, eliminating the need for a conventional oil chamber seal cap. As a result, the number of parts can be reduced, the manufacturing cost can be reduced, and the weight of the apparatus can be reduced.

In addition, because of the double seal, the sealing performance is further improved, and the leakage of hydraulic pressure from between the bolt head 33 and the fitting hole 34 is reliably prevented. Therefore,
The supply of the hydraulic pressure to the first pressure receiving chamber 44 is ensured, and the movement response of the cylindrical gear 39 is improved. In particular, since the hydraulic path directly communicates with the pressure receiving chamber 44 from the cylindrical portion 36, the length can be reduced as compared with a conventional case where an oil chamber or the like is provided,
Pressure loss to the first pressure receiving chamber 44 can be suppressed. As a result,
The movement response of the cylindrical gear 39 is further improved.

Further, since the head 33 of the fixing bolt 30 is inserted into the insertion hole 34 of the sleeve 29 and the entire fixing bolt 30 is closer to the camshaft 22, the coupling strength of the sleeve 29 to the camshaft 22. And the inclination of the entire device including the timing sprocket 21 and the like in the radial direction can be suppressed.

Each of the pressure receiving chambers 4 before and after the flange portion 42
Since the hydraulic pressure is applied relatively to 4, 45, the cylindrical gear 39 can be held at an arbitrary moving position, and the control accuracy of the valve timing according to the change in the engine operating state is improved.

FIG. 3 shows a second embodiment of the present invention.
A part of the oil passage 49 has a passage hole 61 formed not in the fixing bolt 30 but in the axial direction and the radial direction inside the sleeve 29 similarly to the second oil passage 50. Also, the fixing bolt 30
Has a normal shape, and has an outer peripheral surface 33a and an inner end surface 33b of the head 33 and an inner peripheral surface 34a and a bottom surface 34b of the fitting hole 34.
And a seal ring 63 is fitted and held in a seal ring groove 62 formed on the inner end face of the head 33, and the seal ring 63 is inserted into the inner end face 33 b of the head 33. It is crimped between the bottom surface 34b of the hole 34. Therefore, also in this embodiment, a double sealing property is obtained, and the oil pressure leaked into the bolt insertion hole 32 from between the camshaft 22 and the sleeve 29 can be reliably sealed.

The other basic configuration is the same as that of the first embodiment, so that the same operation and effect can be obtained.

The present invention is not limited to the configuration of the above embodiment. For example, without providing the seal rings 38 and 63, only the tight seal between the outer surface of the bolt head 33 and the inner surface of the fitting hole 34 is provided. It is also possible. Further, the phase conversion means is not limited to the cylindrical gear 39, but may have another structure.

[0033]

As is apparent from the above description, according to the valve timing control device of the present invention, a part of the oil passage is formed in a portion other than the head portion of the bolt, not in the conventional oil chamber. At the same time, since the outer surface of the bolt head and the inner surface of the fitting hole are brought into close contact with each other to exert a sealing function, a conventional seal cap is not required at all. Therefore, the number of parts can be reduced, the manufacturing cost can be reduced, and the weight of the apparatus can be reduced.

According to the second and fourth aspects of the present invention, double sealing can be ensured by the seal ring, so that the sealing performance is further improved.

According to the third aspect of the present invention, the structure of the passage is simplified as compared with the prior art, so that the manufacturing workability is improved.

According to the fifth aspect of the present invention, the phase conversion means can be held at an arbitrary position according to the operating state of the engine, so that the control accuracy of the valve timing is improved.

[Brief description of the drawings]

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

FIG. 2 is a front view showing a fixing bolt provided in the embodiment.

FIG. 3 is a sectional view showing a second embodiment of the present invention.

FIG. 4 is a sectional view showing a conventional valve timing control device.

[Explanation of symbols]

 Reference Signs List 21 timing sprocket (rotating body) 22 camshaft 24 front cover 29 sleeve 30 fixing bolt 32 bolt insertion hole 33 head 33a outer peripheral surface 33b inner end surface 34 fitting hole 34a inner peripheral surface 34b ... Bottom surface 35 ... Shaft portion 36 ... Cylinder portion 36a ... Inner end surface 37,62 ... Seal groove 38,63 ... Seal ring 39 ... Cylindrical gear (phase conversion means) 44,45 ... First and second pressure receiving chamber 47 ... Hydraulic circuit 49 first oil passage 50 second oil passage 51, 61 passage hole

Claims (5)

[Claims] A camshaft having a rotating body driven to rotate by an engine, a cam for operating an intake / exhaust valve by a rotating force transmitted from the rotating body, and a cam bolt attached to one end of the camshaft by a fixing bolt in an axial direction. A sleeve that is fixed and inserted through the rotating body, and is interposed between the sleeve and the rotating body, and is operated by hydraulic pressure of a hydraulic circuit to change a relative rotation phase between the rotating body and the camshaft. A valve timing control device provided with a phase conversion means, wherein a part of an oil passage of the hydraulic circuit is formed at a portion excluding a head of a fixing bolt, and a bolt insertion hole is formed in an inner axial direction of the sleeve. Forming an insertion hole into which the head of the fixing bolt is inserted at the outer end side of the bolt insertion hole, and fixing the sleeve to the camshaft by the fixing bolt. A valve timing control system for an internal combustion engine, characterized in that for sealing in close contact with the inner peripheral surface and the bottom surface of the insertion hole fitting the head outer surface of the fixing bolt. 2. The valve timing control device for an internal combustion engine according to claim 1, wherein a seal ring is provided between an outer peripheral surface of a head of the fixing bolt and an inner peripheral surface of the fitting hole. 3. The oil passage according to claim 1, wherein a part of the oil passage is formed radially in a cylindrical portion provided between the shaft portion and the head portion in the axial direction of the shaft portion of the fixing bolt. 1 or 2
A valve timing control device for an internal combustion engine according to any one of the preceding claims. 4. A part of the oil passage is formed inside the sleeve, and a seal ring is provided between a bottom surface of the insertion hole and an inner end surface of a head of the fixing bolt facing the bottom surface. The valve timing control device for an internal combustion engine according to claim 1, wherein: 5. The valve timing control device for an internal combustion engine according to claim 1, wherein the phase conversion means is operated in the camshaft axial direction by front and rear oil pressures.