JP2002295209A - Valve timing adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize a valve timing adjusting device, mounting a torsion coil spring by storing a rotor and shortening the axial direction of the valve timing adjusting device, without the need for installing members (for example, front brake, gear) arranged in the axial direction of the vane rotor. SOLUTION: Since it is not necessary to install a coil storing part 33 in a front plate 1 and a gear 3, and the valve timing adjusting device can be shortened in the axial direction, the coil storing part 33 is formed in the vane rotor 7 which needs the prescribed thickness in the axial direction so as to generate a timing gear and retardant angle. The vane rotor 7 is formed with iron, superior in abrasion resistance, so that abrasion will not occurs even if direct insertion of a coil part into the coil storing part 33 is made. As a result, it is unnecessary to insert an abrasion preventing member with a spring into the coil storing part 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine (hereinafter referred to as "internal combustion engine").
The present invention relates to a valve timing adjusting device for adjusting the opening / closing timing of a valve (an intake valve or an exhaust valve) of an engine.

[0002]

2. Description of the Related Art A valve timing adjusting device includes a shoe housing that rotates with a crankshaft (corresponding to a drive shaft) of an engine, and a vane rotor that rotates with a camshaft (corresponding to a driven shaft). There is known an apparatus that relatively rotates a vane rotor. The vane rotor includes a vane that divides a recess formed in the shoe housing into an advance chamber and a retard chamber. The vane rotor rotates relative to the shoe housing due to a hydraulic pressure difference between the advance chamber and the retard chamber. , The cam shaft changes to the advance side or the retard side.

[0003] During operation of the engine, torque is transmitted in the order of the shoe housing, the vane rotor, and the camshaft to drive the camshaft to the advanced side. That is, a load is applied to the vane rotor in the advance direction. For this reason, when the vane rotor is relatively rotated to the advance side or the retard side,
Responsiveness is lower in the case of relative rotation to the advance side than in the case of relative rotation to the retard side. Also, if the exhaust-side camshaft is in the retarded position together with the intake-side camshaft when the engine is started, the overlap period during which the intake valve and the exhaust valve are simultaneously opened is not appropriate, which may cause a start failure. I will. Therefore, there is a demand for appropriately assisting the camshaft to the advance side in order to appropriately maintain the overlap period between the intake valve and the exhaust valve when starting the engine.

As a technique for solving such a problem,
A torsion coil spring (advancing spring) is engaged with one end of the shoe housing (or a member that rotates integrally with the shoe housing), and the other end is engaged with the vane rotor. 2. Description of the Related Art A valve timing adjustment device that assists is known.

[0005]

In a valve timing adjusting device equipped with a torsion coil spring, the place where the torsion coil spring is arranged becomes structurally important. Conventionally, the torsion coil spring has been arranged in one of the axial directions of the vane rotor. That is, one of the vane rotors (for example,
The torsion coil spring is housed inside a front plate arranged on the front side), or the torsion coil spring is housed inside a gear arranged on the other side (for example, the rear side) of the vane rotor.

However, if the torsion coil spring is housed inside the front plate or the gear, the axial dimension of the front plate or the gear becomes thick, and it is difficult to reduce the size of the valve timing adjusting device. Therefore, it is conceivable to form a space for accommodating the torsion coil spring inside the vane rotor having a certain thickness.

However, since the conventional vane rotor is formed of a material having relatively low hardness such as aluminum and soft iron, if the storage portion for the torsion coil spring is formed, there is a concern that the vane rotor will be worn by the vibration of the torsion coil spring. In order to solve this concern, it is necessary to insert a cylindrical plate such as iron or stainless steel into the housing of the torsion coil spring to avoid interference, and torsion due to the space for inserting the cylindrical plate. The storage part for the coil spring becomes large. Then, the strength of the vane rotor is reduced, or the physique of the vane rotor must be increased in order to take measures against it.

Further, a plurality of oil passages for supplying and discharging hydraulic oil to the advance chamber and the retard chamber are formed inside the vane rotor. In addition to this, a storage section for the torsion coil spring is further provided inside the vane rotor. If it is formed, the strength of the vane rotor is reduced, or the size of the vane rotor must be increased in order to take measures against it. Further, it is difficult to form an oil passage avoiding the storage portion of the torsion coil spring, which causes an increase in cost.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and an object of the present invention is to reduce the size of a valve timing adjusting device equipped with a torsion coil spring.

[0010]

According to the first aspect of the present invention, the coil portion of the torsion coil spring is housed in a coil housing formed inside the vane rotor. This eliminates the need to provide a coil housing in a member (for example, a front plate, a gear, or the like) arranged in the axial direction of the vane rotor, so that the axial direction of the valve timing adjustment device can be shortened.

On the other hand, since the vane rotor is formed of a material having excellent wear resistance (for example, iron or the like), even if the coil portion of the torsion coil spring is directly inserted into the coil storage portion of the vane rotor, the vibration of the torsion coil spring causes The problem that the vane rotor is worn does not occur. This eliminates the need to insert a member (for example, a tubular plate or the like) for preventing abrasion due to the interference of the spring into the inside of the coil housing, so that there is no problem that the coil housing becomes large and the strength of the vane rotor decreases. In addition, there is no problem that the size of the vane rotor is increased to compensate for the decrease in strength.

According to a second aspect of the present invention, in the valve timing adjusting apparatus employing the second aspect, the coil housing portion of the vane rotor is used as a part of an oil passage communicating with the advance chamber or the retard chamber. For this reason, the cutting amount of the vane rotor is reduced, and as a result, there is no problem that the strength of the vane rotor is reduced or the physical size of the vane rotor is increased to compensate for the reduced strength. Further, it is difficult to form an oil passage avoiding the coil housing portion. However, since the coil housing portion is used as an oil passage, the number of oil passages avoiding the coil housing portion is reduced. For this reason, it is easy to form an oil passage in the vane rotor, and it is possible to suppress the manufacturing cost of the vane rotor, and as a result, the cost of the valve timing adjusting device.

According to a third aspect of the present invention, there is provided a valve timing adjusting apparatus employing the third aspect of the present invention, wherein an oil passage is punched in a plate interposed between the shoe housing and the gear, and the oil passage is connected to the shoe housing. It was interposed between the gears and cut off from the outside. This oil passage is used, for example, as an oil passage for supplying hydraulic oil to a stopper pin for locking the shoe housing and the vane rotor. If you try to form an oil path on the gear side of the shoe housing,
Since it is necessary to form a groove serving as an oil passage on the side surface of the hard gear, the cost increases. However, by adopting the means of claim 3, since the oil passage can be formed by punching a plate, the cost can be suppressed as compared with the case where the groove of the oil passage is machined in the gear.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to examples and modifications. [Embodiment] An embodiment will be described with reference to FIGS. FIG. 1 is a cross-sectional view along the axial direction of the valve timing adjusting device.
FIG. 2 is a view showing the inside of the shoe housing. In addition,
The valve timing adjusting apparatus shown in this embodiment is mounted on a camshaft on the intake side of a DOHC engine in which an intake valve and an exhaust valve are driven by independent camshafts. It can be dynamically changed. In this embodiment, the left side of FIG. 1 is described as a front side, and the right side is described as a rear side.

The valve timing adjusting device is driven by a crankshaft via a timing chain (or a timing belt), and is driven by the driving member A to transmit the driving torque to the camshaft C. The driven member B is relatively rotated with respect to the driving member A by a configuration described later, and changes the camshaft C to the advanced or retarded side. is there.

The driving member A is composed of a front plate 1, a shoe housing 2, and a gear 3 from the front side, and rotates in synchronization with a crankshaft. A plate 4 for closing the rear side of an oil chamber (an advance chamber 6a and a retard chamber 6b described later) formed inside the housing 2 is interposed. These front plate 1, shoe housing 2,
The gear 3 and the plate 4 are firmly fastened by a plurality of bolts 5. The drive member A is rotated clockwise in FIG. 2 by the timing chain, and the rotation direction is the advance direction. As shown in FIG. 2, a plurality (three in this embodiment) of substantially fan-shaped concave portions 6 are formed inside the shoe housing 2.

On the other hand, the driven member B has a vane rotor 7 which rotates integrally with the camshaft C. The vane rotor 7 has a positioning groove 9 that fits into a positioning pin 8 fixed to the camshaft C, and the positioning pin 8 and the positioning groove 9 fit together.
The positioning of the vane rotor 7 with respect to the camshaft C is performed. Further, the vane rotor 7 has a camshaft C
Is fixed to the camshaft C by being pressed against a step portion 11 formed on the camshaft C by a nut 10 fastened to the camshaft C. A substantially ring-shaped spacer 10a is interposed between the nut 10 and the vane rotor 7, and the spacer 10a is provided so as to transmit the fastening force of the nut 10 to the vane rotor 7.

The vane rotor 7 partitions the interior of the recess 6 of the shoe housing 2 into an advance chamber 6a and a retard chamber 6b.
The vane rotor 7 is provided so as to be rotatable within a predetermined angle with respect to the shoe housing 2. The advancing chamber 6a and the retarding chamber 6b are hydraulic chambers surrounded by the front plate 1, the shoe housing 2, the plate 4, and the vane rotor 7. Sex is maintained. The advance chamber 6a is provided with a vane 1 by hydraulic pressure.
2 is a hydraulic chamber for driving the vane 12 to the advance side.
In contrast, the retard chamber 6b is a hydraulic chamber for driving the vane 12 to the retard side by hydraulic pressure, and is formed on the rotational direction side of the vane 12. It is formed in the recess 6.

The valve timing adjusting device includes an advance chamber 6a.
Further, a hydraulic pressure difference generating means for supplying and discharging a fluid (oil) to / from the retard chamber 6b to generate a hydraulic pressure difference between the advance chamber 6a and the retard chamber 6b is provided. This hydraulic pressure difference generating means is provided in the advance chamber 6a.
This is means for causing the vane rotor 7 to rotate relative to the shoe housing 2 by generating a hydraulic pressure difference in the retard chamber 6b.

FIG. 3 shows an example of this means. The oil pressure difference generating means includes an oil pump 13 driven by a crankshaft, a switching valve 14 for switching and supplying oil pumped by the oil pump 13 to the advance chamber 6a or the retard chamber 6b. Electromagnetic actuator 15 for switching drive, switching valve 1 for draining advance chamber 6a at the same time as retard chamber 6b is being drained
6, an electromagnetic actuator 17 for switching and driving the switching valve 16, an electronic control unit (ECU not shown) for controlling the two electromagnetic actuators 15, 17, and the like. The ECU controls the electromagnetic actuators 15 and 17 according to the operating state of the engine such as the crank angle, the engine rotation speed, and the accelerator opening detected by the various sensors, and adjusts the operating oil pressure according to the operating state of the engine. It is generated in the advance chamber 6a and the retard chamber 6b.

On the other hand, the rotation position of the vane rotor 7 is fixed to one of the vanes 12 at a predetermined intermediate phase (for example, a position rotated from the most retarded position to the advanced side by 10 °) when the engine is started. A stopper pin 20 for mounting is mounted. The locking structure of the shoe housing 2 and the vane rotor 7 by the stopper pin 20 is added to FIGS.
A description will be given also with reference to a schematic explanatory view of the lock structure shown in FIG.

The stopper pin 20 is inserted into an insertion hole formed in the vane 12, and is
It is fixed so that it does not protrude beyond a predetermined amount. A biasing force toward the front side is applied to the stopper ring 21 by a compression coil spring 22. A ring-shaped stopper bush 2 fixed to the front plate 1
The shoe housing 2 with the head (front end) of the stopper pin 20 fitted into the stopper hole 23a in the shoe housing 2
, The vane rotor 7 is locked.

The front surface of the stopper pin 20 communicates with the retard chamber 6b by a groove (not shown) formed in the front plate 1, and the hydraulic pressure in the retard chamber 6b causes the stopper pin 20 to release the lock on the unlocking side. (Rear side). A flange-shaped flange portion 24 that receives hydraulic pressure from both the front side and the rear side is formed at an intermediate portion of the stopper pin 20. Flange 24
The oil chamber (front oil chamber) 25 on the front side is provided so as to communicate with the retard chamber 6b in the unlocked state, and the hydraulic pressure in the retard chamber 6b causes the stopper pin 20 to release the lock on the unlock side ( (Rear side).

On the other hand, an oil chamber (rear oil chamber) 26 on the rear side of the flange portion 24 communicates with the advance chamber 6a via a lateral hole 27 formed in the vane 12, and the hydraulic pressure of the advance chamber 6a The stopper pin 20 is provided so as to bias the lock pin (front side). The rear oil chamber 26 is provided so as to be able to communicate with the advance chamber 6 a via an oblique hole 28 formed in the vane rotor 7 and an elongated hole 29 formed in the plate 4. As shown in FIG. 3, the oblong hole 28 formed in the plate 4 connects the advance chamber 6a and the rear oil chamber 26 with the oblique hole 28 when the vane 12 (stopper pin 20) is rotating to the advance side. When the stopper pin 20 is turned to the most retarded side, the communication with the oblique hole 28 is interrupted.

The elongated hole 29 is an oil passage formed simultaneously when the plate 4 is punched from a thin plate. The elongated hole 29 (punched oil passage) is sandwiched between the shoe housing 2 and the gear 3. It is shut off from the outside (atmosphere).

As shown in FIG. 1, the lock mechanism is arranged so that the spring chamber 30 in which the compression coil spring 22 is disposed communicates with the atmosphere at a position where the head of the stopper pin 20 fits into the stopper hole 23a. It is provided in. The atmosphere communication means of this embodiment is an atmosphere opening hole 31 formed in the gear 3, and when the lock is released, the spring chamber 3 is opened.
Numeral 0 indicates that the stopper pin 20 is dumped while being shut off from the atmosphere.

An outline of the operation of the lock mechanism will be described.
When a stop instruction is given to the engine, an ECU (not shown)
As a result, the retard chamber 6b side is drained, hydraulic pressure is supplied to the advance chamber 6a side, and the vane rotor 7 rotates to the advance side. When the vane rotor 7 rotates more advanced than the lock position, hydraulic pressure is supplied to the rear oil chamber 26 through the elongated hole 29 and the lateral hole 27 as shown in FIG. Then, the force for pushing the stopper pin 20 to the front side together with the compression coil spring 22 exceeds, and the stopper pin 20 contacts the front plate 1. The engine stops in this state.

When the engine is started, both the advance chamber 6a and the retard chamber 6b are drained by the operation of the ECU.
When the driving member A is driven by the crankshaft to the advance side, the load of the camshaft C is applied to the driven member B, so that the shoe housing 2 rotates to the advance side, and the vane rotor 7 moves to the retard side. When the phase position of the vane rotor 7 rotates to the lock position, the stopper pin 20 is fitted into the stopper hole 23a by the action of the compression coil spring 22, and as a result, the shoe housing 2 and the vane rotor 7 are locked at a predetermined intermediate phase. I do.
That is, the engine can be started with the intake-side camshaft locked at the predetermined intermediate phase.

The valve timing adjusting device includes a driving member A
, A torsion coil spring (advance assist spring) 32 for urging the driven member B toward the advance side is provided.
The torsion coil spring 32 facilitates the rotation of the vane rotor 7 to the advance side from the lock position when the engine is stopped. One end of the torsion coil spring 32 is engaged with the shoe housing 2 or a member that rotates integrally with the shoe housing 2, and the other end is engaged with the vane rotor 7. In this embodiment, one end of the torsion coil spring 32 is , Is inserted into and engaged with an insertion hole 3 a formed in the gear 3.

The other end of the torsion coil spring 32 directly engages with the vane rotor 7 as described above, and is inserted into and engaged with an insertion hole 7a formed in the vane rotor 7. The coil portion of the torsion coil spring 32 is formed by a coil housing 3 formed inside the vane rotor 7.
3 is housed inside. The vane rotor 7
It is formed of a material having excellent wear resistance, such as iron, and there is no problem of being worn by contact with the torsion coil spring 32. That is, it is not necessary to arrange a member (a tubular plate or the like) for avoiding interference around the coil portion, and the size of the coil housing portion 33 is prevented from being increased.

On the other hand, the advance chamber 6a communicates with the advance oil passage 34a in the camshaft C via the advance oil passage 34 formed inside the vane rotor 7, and the retard chamber 6b is also connected to the vane rotor 7 Communicates with a retard oil passage 35a in the camshaft C through a retard oil passage 35 formed inside the camshaft C. The advance oil passage 34a and the retard oil passage 35a in the camshaft C are described above. It communicates with the hydraulic pressure difference generating means. In this embodiment, the coil housing portion 33 is used as a part of the advance oil passage 34 communicating with the advance chamber 6a. That is, the oil supplied to and discharged from the advance chamber 6a is
It is supplied and discharged through the coil housing 33. As described above, by using the coil housing portion 33 as a part of the advance oil passage 34, the only oil passage that avoids the coil housing portion 33 is the retard oil passage 35. For this reason, it is easy to form an oil passage in the vane rotor 7, and the manufacturing cost of the vane rotor 7 can be suppressed.

In the valve timing adjusting device shown in this embodiment, a coil housing portion 33 is formed in the vane rotor 7 which needs a predetermined axial thickness to generate an advance torque and a retard torque, and a torsion coil spring is provided therein. Since the 32 coil portions are housed, there is no need to provide the coil housing portion 33 in the front plate 1, the gear 3, or the like. For this reason, the axial direction of the front plate 1 or the gear 3 which has accommodated the torsion coil spring 32 can be made thinner, and as a result, the valve timing adjusting device can be shortened in the axial direction.

Since the vane rotor 7 is formed of a material having excellent wear resistance (for example, iron or the like), even if the coil portion is directly inserted into the coil housing portion 33, the vibration of the torsion coil spring 32 causes the vane rotor 7 to vibrate. There is no failure to wear. As a result, it is not necessary to insert a member (for example, a cylindrical plate or the like) for preventing abrasion due to the interference of the spring into the inside of the coil housing portion 33, so that there is no problem that the coil housing portion 33 becomes large. There is no problem that the strength is reduced or the physique of the vane rotor 7 is increased to compensate for the reduction in the strength.

Further, in the valve timing adjusting device of this embodiment, the coil housing portion 33 is used as a part of the advance oil passage 34. For this reason, the cutting amount of the vane rotor 7 is reduced, and as a result, there is no problem that the strength of the vane rotor 7 is reduced or the physique of the vane rotor 7 is increased to compensate for the reduced strength. Although it is difficult to form an oil passage avoiding the coil housing portion 33, the oil passage avoiding the coil housing portion 33 becomes a retard oil by using the coil housing portion 33 as the advance oil passage 34. Only road 35 is enough. For this reason, it is easy to form an oil passage in the vane rotor 7, and it is possible to reduce the manufacturing cost of the vane rotor 7 and, as a result, the cost of the valve timing adjusting device.

On the other hand, in the valve timing adjusting device of this embodiment, when the vane rotor 7 is at or above a predetermined phase, a part of an oil passage for communicating the advance chamber 6a and the rear oil chamber 26 is formed as an elongated hole 29 and the plate 4 is used. Formed. If the elongated hole 29 is to be formed in the gear 3, it is necessary to machine a groove corresponding to the elongated hole 29 on the side surface of the hard gear 3, which increases the cost. However, the slot 2 of this embodiment
9 is formed at the same time when the plate 4 is punched, and can be formed at low cost. Thereby, the cost of the valve timing adjusting device can be reduced.

[Modification] In the above embodiment, an example was shown in which the coil housing portion 33 was used as a part of the advance oil passage 34 communicating with the advance chamber 6a. 6
It may be used as a part of the retard oil passage 35 communicating with b. In this case, as with the case where the coil housing portion 33 is used as the advance oil passage 34, only the advance oil passage 34 is required to avoid the coil housing portion 33, and it is easy to form the oil passage in the vane rotor 7. And the manufacturing cost of the vane rotor 7 can be reduced. Further, although it is somewhat difficult to form an oil passage in the vane rotor 7, the coil housing 33 is not used as the advance oil passage 34 and the advance oil passage 34, but the coil housing 33 is avoided. The passage 34 and the advance oil passage 34 may be formed.

In the above embodiment, the example in which the coil accommodating portion 33 is formed on the gear 3 side of the vane rotor 7 has been described. In the above example,
Although the example in which the present invention is applied to the valve timing adjusting device of the type in which the camshaft C penetrates the inside of the vane rotor 7 has been described, the present invention is applied to the valve timing adjusting device of the type fastened to the end of the camshaft C. You may.
In the above embodiment, the example in which the present invention is applied to the valve timing adjusting device attached to the camshaft C on the intake side is shown. However, the present invention is applied to the valve timing adjusting device attached to the camshaft C on the exhaust side. May be.
In such a case, the lock mechanism may be provided so as to lock the vane rotor 7 to the most advanced side.

In the above embodiment, the stopper pin 20 moves in the front direction and fits in the stopper hole 23a. However, the stopper pin 20 moves in the rear direction and fits in the stopper hole 23a. The stopper pin 20 may be provided so as to be fitted in the stopper hole 23a by moving the stopper pin 20 in the radial direction. Further, although the example in which the stopper pin 20 is housed in the vane rotor 7 side is shown, the stopper pin 20 may be housed in the shoe housing 2 side to lock the vane rotor 7.

In the above embodiment, three recesses 6 are formed in the shoe housing 2, and three recesses 6 are formed on the outer periphery of the vane rotor 7.
Although an example in which one vane 12 is provided is shown, the number of the recesses 6 and the number of the vanes 12 may be any number as long as the number of the recesses 6 and the number of the vanes 12 are one or more. Other numbers may be used. That is, for example, two recesses 6 may be formed in the shoe housing 2 and two vanes 12 may be provided on the outer periphery of the vane rotor 7, or four recesses 6 may be formed in the shoe housing 2 and the outer periphery of the vane rotor 7 May be provided with four vanes 12.

In the above embodiment, the shoe housing 2 rotates with the crankshaft (drive shaft) and the vane rotor 7 rotates with the camshaft C (driven shaft). However, the vane rotor 7 rotates with the crankshaft (drive shaft). ), The shoe housing 2 may rotate with the camshaft C (driven shaft).

[Brief description of the drawings]

FIG. 1 is a sectional view along an axial direction of a valve timing adjusting device.

FIG. 2 is a diagram showing the inside of a shoe housing.

FIG. 3 is a schematic explanatory view of a lock structure.

[Explanation of symbols]

 C Camshaft (driven shaft) 2 Shoe housing 3 Gear 4 Plate 6 Concave portion 6a Advance chamber 6b Delay chamber 7 Vane rotor 12 Vane 29 Elongated hole (punched oil passage) 32 Torsion coil spring 33 Coil housing portion 34 Advance oil passage (coil) Oil passage using storage section)

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3G018 AB02 BA33 BA36 CA20 DA25 DA26 DA73 DA77 DA84 DA85 DA86 EA21 EA31 EA33 FA01 FA07 FA16 GA11 GA14 GA18

Claims (3)

[Claims] 1. A driving force transmission system for transmitting driving force from a driving shaft of an internal combustion engine to a driven shaft for opening and closing a valve,
A valve timing adjustment device that causes a phase difference in rotation of the driven shaft with respect to rotation of the drive shaft, wherein the valve timing adjustment device rotates with one of the drive shaft or the driven shaft, A vane rotor that rotates with the other of the drive shaft and the driven shaft and that defines a recess formed in the shoe housing into an advance chamber and a retard chamber; and advancing the vane rotor with respect to the shoe housing. A torsion coil spring biasing to the side or the retard side, wherein the vane rotor is made of a material having excellent wear resistance, and a coil portion of the torsion coil spring is housed in a coil housing portion formed inside the vane rotor. A valve timing adjustment device characterized by being performed. 2. The valve timing adjusting device according to claim 1, wherein the coil housing is used as a part of an oil passage communicating with the advance chamber or the retard chamber. apparatus. 3. The valve timing adjusting device according to claim 1, wherein a gear for driving the shoe housing is fixed to one surface in an axial direction of the shoe housing with a plate interposed therebetween. An oil passage is formed in the plate by punching,
The valve timing adjusting device is characterized in that the punching oil passage is interposed between the shoe housing and the gear and is isolated from the outside.