JP4304878B2 - Valve timing adjustment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a valve timing adjusting device that adjusts the opening / closing valve timing of a valve (an intake valve or an exhaust valve) of an internal combustion engine (hereinafter referred to as an engine).
[0002]
[Prior art]
The valve timing adjustment device includes a shoe housing that rotates with the engine crankshaft (corresponding to the drive shaft) and a vane rotor that rotates with the camshaft (corresponding to the driven shaft), and the vane rotor rotates relative to the shoe housing. What is to be known is known. The vane rotor includes a vane that divides a recess formed in the shoe housing into an advance chamber and a retard chamber, and the vane rotor rotates relative to the shoe housing due to a hydraulic pressure difference between the advance chamber and the retard chamber. The camshaft changes to the advance side or the retard side.
[0003]
During operation of the engine, torque is transmitted in the order of shoe housing → vane rotor → camshaft, and the camshaft is driven to the advance side. That is, a load is applied to the vane rotor in the advance direction. For this reason, when the vane rotor is rotated relative to the advance side or the retard side, the responsiveness is lowered when the vane rotor is rotated relative to the advance side compared to the relative rotation toward the retard side.
Also, if the exhaust camshaft and the intake camshaft are at a retarded position when the engine is started, the overlap period during which the intake valve and the exhaust valve open at the same time is not appropriate, which may cause a start failure. End up. Therefore, there is a demand for assisting the camshaft appropriately to advance the camshaft in order to properly maintain the overlap period between the intake valve and the exhaust valve when the engine is started.
[0004]
As a technique for solving such problems, a torsion coil spring (advance spring) having one end engaged with a shoe housing (or a member that rotates integrally with the shoe housing) and the other end engaged with a vane rotor is provided. A valve timing adjusting device that assists the vane rotor toward the advance side with respect to the shoe housing is known.
[0005]
[Problems to be solved by the invention]
In a valve timing adjusting device equipped with a torsion coil spring, the place where the torsion coil spring is arranged is structurally important.
Conventionally, the torsion coil spring has been arranged in either one of the axial directions of the vane rotor.
That is, a torsion coil spring is accommodated in the front plate disposed on one (for example, front side) surface of the vane rotor, or a torsion coil spring is disposed in the gear disposed on the other (for example, rear side) surface of the vane rotor. Was stored.
[0006]
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, making it difficult to reduce the size of the valve timing adjusting device.
Therefore, it is conceivable to form a space in which the torsion coil spring is accommodated inside the vane rotor that requires a certain thickness.
[0007]
However, since the conventional vane rotor is formed of aluminum ( a material having a relatively low hardness ) , there is a concern that the vane rotor may be worn by the vibration of the torsion coil spring when the housing portion of the torsion coil spring is formed.
In order to eliminate this concern, a cylindrical plate made of iron or stainless steel to avoid interference must be inserted inside the housing of the torsion coil spring, and the torsion is made by the space for inserting the cylindrical plate. The storage part of the coil spring becomes large. Then, the intensity | strength of a vane rotor falls or it becomes necessary to enlarge the physique of a vane rotor for the countermeasure.
[0008]
Further, in the interior of the vane rotor, a plurality of oil passages for supplying and discharging hydraulic oil to and from the advance chamber and the retard chamber are formed, but in addition to that, when a storage portion of a torsion coil spring is formed inside the vane rotor, The strength of the vane rotor is reduced or the physique of the vane rotor has to be enlarged for the countermeasure. In addition, it is difficult to form the oil passage by avoiding the storage portion of the torsion coil spring, which causes an increase in cost.
[0009]
OBJECT OF THE INVENTION
The present invention has been made to solve the above-described problems, and an object thereof is to reduce the physique of a valve timing adjusting device equipped with a torsion coil spring.
[0010]
[Means for Solving the Problems]
[Means of Claim 1]
In the valve timing adjusting apparatus employing the first aspect, all of the coil portions of the torsion coil spring are accommodated in the coil accommodating portion formed inside the vane rotor. As a result, it is not necessary to provide a coil housing portion in a member (for example, a front plate or a gear) arranged in the axial direction of the vane rotor, and the axial direction of the valve timing adjusting device can be shortened.
[0011]
Meanwhile, the vane rotor is to be formed by the excellent iron wear resistance, inserting all of the coil portion directly in torsion coil spring in the coil receiving portion of the vane rotor, bugs vane rotor is worn by the vibration of the torsion coil spring is generated do not do. As a result, it is not necessary to insert a member (for example, a cylindrical plate) for preventing wear due to the interference of the spring into the inside of the coil housing portion, so there is no problem that the coil housing portion becomes large, and the strength of the vane rotor is reduced. And the problem that the physique of the vane rotor becomes large in order to compensate for this decrease in strength does not occur.
[0012]
[Means of claim 2]
In the valve timing adjusting apparatus adopting the means of claim 2, the coil housing portion of the vane rotor is used as a part of the oil passage communicating with the advance chamber or the retard chamber. For this reason, the amount of cutting of the vane rotor is reduced, and as a result, the strength of the vane rotor does not decrease, and the problem that the physique of the vane rotor increases to compensate for this strength reduction does not occur.
In addition, it is difficult to form an oil passage by avoiding the coil housing portion, but when the coil housing portion is used as an oil passage, the oil passage to avoid the coil housing portion is reduced. For this reason, it becomes easy to form an oil passage in the vane rotor, the manufacturing cost of the vane rotor can be suppressed, and as a result, the cost of the valve timing adjusting device can be suppressed.
[0013]
[Means of claim 3]
In the valve timing adjusting device adopting the means of claim 3, an oil passage is provided in a punched plate in the shoe housing and the gear, and the oil passage is sandwiched between the shoe housing and the gear so as to be shut off from the outside. did. This oil passage is used as an oil passage for supplying hydraulic oil to a stopper pin that locks the shoe housing and the vane rotor, for example.
If an oil passage is to be formed on the gear side of the shoe housing, it is necessary to process a groove serving as an oil passage on the side surface of the hard gear, resulting in an increase in cost. However, since the oil passage can be formed by punching a plate by adopting the means of claim 3, the cost can be reduced as compared with the case where the groove of the oil passage is processed in the gear.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described using examples and modifications.
〔Example〕
An embodiment will be described with reference to FIGS. FIG. 1 is a sectional view along the axial direction of the valve timing adjusting device, and FIG. 2 is a view showing the inside of the shoe housing. The valve timing adjusting device shown in this embodiment is attached to the intake side camshaft of a DOHC engine in which an intake valve and an exhaust valve are driven by independent camshafts. Alternatively, it can be varied step by step. In this embodiment, the left side of FIG. 1 will be described as the front side and the right side as the rear side.
[0015]
The valve timing adjusting device includes a driving member A driven from a crankshaft via a timing chain (or a timing belt), and a driven member B that is driven by the driving member A and transmits the driving torque to the camshaft C. The driven member B rotates relative to the drive member A according to the configuration described later, and the camshaft C is changed to the advance side or the retard side.
[0016]
The drive 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 the crankshaft. Between the shoe housing 2 and the gear 3, 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 is interposed. These front plate 1, shoe housing 2, gear 3 and 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 this rotation direction is the advance direction. As shown in FIG. 2, a plurality of substantially fan-shaped recesses 6 (three in this embodiment) are formed inside the shoe housing 2.
[0017]
On the other hand, the driven member B includes a vane rotor 7 that rotates integrally with the camshaft C. The vane rotor 7 includes a positioning groove 9 that fits in a positioning pin 8 fixed to the camshaft C, and the positioning pin 8 and the positioning groove 9 fit into each other, whereby the vane rotor 7 with respect to the camshaft C is fitted. Positioning has been made. Further, the vane rotor 7 is fixed to the camshaft C by being pressed against the step portion 11 formed on the camshaft C by the nut 10 fastened to the camshaft C. A substantially ring-shaped spacer 10 a is interposed between the nut 10 and the vane rotor 7. The spacer 10 a is provided so as to transmit the fastening force of the nut 10 to the vane rotor 7.
[0018]
The vane rotor 7 includes a vane 12 that divides 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. It has been. The advance chamber 6 a and the retard chamber 6 b are hydraulic chambers surrounded by the front plate 1, the shoe housing 2, the plate 4, and the vane rotor 7, and are liquid-tight in each chamber by a seal member 12 a and the like disposed in the tip groove of the vane 12. Sex is maintained.
The advance chamber 6a is a hydraulic chamber for driving the vane 12 to the advance side by hydraulic pressure, and is formed in the recess 6 on the side opposite to the rotation direction of the vane 12, and conversely, the retard chamber. Reference numeral 6b denotes a hydraulic chamber for driving the vane 12 to the retard side by hydraulic pressure, and is formed in the recess 6 on the rotation direction side of the vane 12.
[0019]
The valve timing adjusting device is provided with hydraulic pressure difference generating means for supplying and discharging fluid (oil) to the advance chamber 6a and the retard chamber 6b to generate a hydraulic pressure difference between the advance chamber 6a and the retard chamber 6b. . This hydraulic pressure difference generating means is a means for rotating the vane rotor 7 relative to the shoe housing 2 by generating a hydraulic pressure difference between the advance chamber 6a and the retard chamber 6b.
[0020]
An example of this means is shown in FIG. This hydraulic pressure difference generating means includes an oil pump 13 driven by a crankshaft, a switching valve 14 for supplying oil pumped by the oil pump 13 to the advance chamber 6a or the retard chamber 6b, and this switch valve 14 An electromagnetic actuator 15 for switching driving, a switching valve 16 for simultaneously draining the advance chamber 6a when the retarding chamber 6b is drained, an electromagnetic actuator 17 for switching and driving the switching valve 16, the two electromagnetic actuators 15, An electronic control unit (ECU not shown) that controls the motor 17 is configured. The ECU controls the electromagnetic actuators 15 and 17 in accordance with the engine operating state such as the crank angle, the engine rotation speed, the accelerator opening, and the like detected by various sensors, so that the hydraulic pressure corresponding to the engine operating state is set. It is generated in the advance chamber 6a and the retard chamber 6b.
[0021]
On the other hand, one of the vanes 12 is used to fix the rotation position of the vane rotor 7 at a predetermined intermediate phase (for example, a position rotated from the most retarded position to the 10 ° advance side) when the engine is started. A stopper pin 20 is attached.
The lock structure of the shoe housing 2 and the vane rotor 7 by the stopper pin 20 will be described with reference to the schematic explanatory view of the lock structure shown in FIG. 3 in addition to FIGS.
[0022]
The stopper pin 20 is inserted into an insertion hole formed in the vane 12, and is fixed by a stopper ring 21 so as not to protrude more than a predetermined amount. A biasing force toward the front side is applied to the stopper ring 21 by a compression coil spring 22. Then, the vane rotor 7 is locked to the shoe housing 2 in a state where the head (front end) of the stopper pin 20 is fitted in the stopper hole 23a in the ring-shaped stopper bush 23 fixed to the front plate 1. Is done.
[0023]
The front surface of the stopper pin 20 communicates with the retard chamber 6b through a groove (not shown) formed in the front plate 1, and the stopper pin 20 is unlocked (rear side) by the hydraulic pressure of the retard chamber 6b. ).
A flange-like 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. The oil chamber (front oil chamber) 25 on the front side of the flange portion 24 is provided so as to communicate with the retard chamber 6b in the unlocked state, and the stopper pin 20 is locked by the hydraulic pressure of the retard chamber 6b. Energize to the release side (rear side).
[0024]
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 through a lateral hole 27 formed in the vane 12, and the stopper pin 20 is driven by the hydraulic pressure of the advance chamber 6a. Is urged toward the lock side (front side).
Further, the rear oil chamber 26 is provided so as to be able to communicate with the advance chamber 6 a through an oblique hole 28 formed in the vane rotor 7 and a long hole 29 formed in the plate 4. As shown in FIG. 3, the long hole 29 formed in the plate 4 allows the advance chamber 6 a and the rear oil chamber 26 to pass through the oblique hole 28 when the vane 12 (stopper pin 20) is rotated to the advance side. However, when the stopper pin 20 is rotated to the most retarded angle side, the communication with the oblique hole 28 is blocked.
[0025]
The long hole 29 is an oil passage formed simultaneously when the plate 4 is punched from a thin plate, and the long hole 29 (punching oil passage) is sandwiched between the shoe housing 2 and the gear 3 and externally (atmosphere). ).
[0026]
As shown in FIG. 1, the lock mechanism is provided 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 is fitted in the stopper hole 23a. ing. The atmosphere communicating means of this embodiment is an atmosphere opening hole 31 formed in the gear 3, and the spring chamber 30 is cut off from the atmosphere at the position where the lock is released, and the stopper pin 20 is dumped.
[0027]
An outline of the operation of this locking mechanism will be described. When a stop instruction is given to the engine, the retard chamber 6b is drained by the action of an ECU (not shown), the hydraulic pressure is supplied to the advance chamber 6a, and the vane rotor 7 rotates to the advance side. When the vane rotor 7 rotates to the advance side from the locked position, the hydraulic pressure is supplied to the rear oil chamber 26 through the long hole 29 and the lateral hole 27 as shown in FIG. Then, the force that pushes the stopper pin 20 to the front side together with the compression coil spring 22 increases, and the stopper pin 20 comes into contact with the front plate 1. In this state, the engine stops.
[0028]
When the engine is started, the advance chamber 6a and the retard chamber 6b are both drained by the action of the ECU. When the drive member A is driven to the advance side by the crankshaft, the load of the camshaft C is applied to the driven member B, so the shoe housing 2 rotates to the advance side, and the vane rotor is relatively moved. 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. To do. That is, the engine can be started with the intake-side camshaft locked to a predetermined intermediate phase.
[0029]
The valve timing adjusting device is provided with a torsion coil spring (advance assist spring) 32 that urges the driven member B toward the advance side with respect to the drive member A. The torsion coil spring 32 is for facilitating the rotation of the vane rotor 7 from the lock position to the advance side when the engine is stopped.
One end of the torsion coil spring 32 engages with the shoe housing 2 or a member that rotates integrally with the shoe housing 2, and the other end engages with the vane rotor 7. In this embodiment, one end of the torsion coil spring 32 is The gear 3 is inserted into and engaged with an insertion hole 3a formed in the gear 3.
[0030]
The other end of the torsion coil spring 32 is directly engaged with the vane rotor 7 as described above, and is inserted into the insertion hole 7a formed in the vane rotor 7 and engaged therewith.
All of the coil portions in the torsion coil spring 32 are accommodated in a coil accommodating portion 33 formed in the vane rotor 7. The vane rotor 7 is formed of iron having excellent wear resistance , 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 cylindrical plate or the like) for avoiding interference around the coil portion, and the coil storage portion 33 is prevented from being enlarged.
[0031]
On the other hand, the advance chamber 6 a communicates with the advance oil passage 34 a in the camshaft C through the advance oil passage 34 formed in the vane rotor 7, and the retard chamber 6 b is also in the vane rotor 7. The retarded oil passage 35a communicates with the retarded oil passage 35a in the camshaft C via the formed retarded oil passage 35, and the advance oil passage 34a and the retarded oil passage 35a in the camshaft C generate the above-described hydraulic pressure difference. It communicates with the 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 6 a is supplied and discharged through the coil storage portion 33.
As described above, by using the coil housing portion 33 as a part of the advance oil passage 34, only the retard oil passage 35 is required to avoid the coil housing portion 33. For this reason, it becomes easy to form an oil path in the vane rotor 7, and the manufacturing cost of the vane rotor 7 can be suppressed.
[0032]
In the valve timing adjusting apparatus shown in this embodiment, the coil housing portion 33 is formed in the vane rotor 7 that requires a predetermined axial thickness in order to generate the advance angle torque and the retard angle torque, and the coil in the torsion coil spring 32 is formed therein. Since all of the parts are housed, it is not necessary to provide the coil housing part 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 in which the torsion coil spring 32 has been accommodated can be thinned, and as a result, the valve timing adjusting device can be shortened in the axial direction.
[0033]
In addition, since the vane rotor 7 is formed of iron having excellent wear resistance, even if the coil portion is directly inserted into the coil housing portion 33, there is no problem that the vane rotor 7 is worn due to vibration of the torsion coil spring 32. This eliminates the need to insert a member (for example, a cylindrical plate or the like) for preventing wear due to the interference of the spring into the coil housing portion 33, so that there is no problem that the coil housing portion 33 becomes large, and the vane rotor 7 There is no problem that the strength is lowered or the physique of the vane rotor 7 is enlarged to compensate for the strength reduction.
[0034]
Further, in the valve timing adjusting device of this embodiment, the coil storage portion 33 is used as a part of the advance oil passage 34. For this reason, the amount of cutting of the vane rotor 7 is reduced, and as a result, the strength of the vane rotor 7 is reduced, and the problem that the physique of the vane rotor 7 is enlarged to compensate for the strength reduction does not occur. In addition, it is difficult to form an oil passage by avoiding the coil housing portion 33, but by using the coil housing portion 33 as the advance oil passage 34, the oil passage avoiding the coil housing portion 33 is retarded oil. Only road 35 is sufficient. For this reason, it becomes easy to form an oil passage in the vane rotor 7, the manufacturing cost of the vane rotor 7 can be suppressed, and as a result, the cost of the valve timing adjusting device can be suppressed.
[0035]
On the other hand, in the valve timing adjusting device of this embodiment, a part of the oil passage for communicating the advance chamber 6a and the rear oil chamber 26 when the vane rotor 7 has a predetermined phase or more is formed in the plate 4 as a long hole 29. . When it is going to form this long hole 29 in the gear 3, since it is necessary to process the groove | channel corresponding to the long hole 29 in the side surface of the hard gear 3, cost will become high. However, since the long hole 29 of this embodiment is punched at the same time when the plate 4 is punched, it can be formed at a low cost. Thereby, the cost of the valve timing adjusting device can be suppressed.
[0036]
[Modification]
In the above embodiment, the coil storage portion 33 is used as a part of the advance oil passage 34 communicating with the advance chamber 6a. However, the retard oil that communicates the coil storage portion 33 with the retard chamber 6b. It may be used as a part of the path 35. In this case, as in the case where the coil storage portion 33 is used as the advance oil passage 34, the oil passage that avoids the coil storage portion 33 is only the advance oil passage 34, and it is easy to form an oil passage in the vane rotor 7. Thus, the manufacturing cost of the vane rotor 7 can be suppressed. In addition, although it is somewhat difficult to form an oil passage in the vane rotor 7, the coil storage portion 33 is not used as the advance oil passage 34 and the advance oil passage 34, and the advance oil is avoided by avoiding the coil storage portion 33. The passage 34 and the advance oil passage 34 may be formed.
[0037]
In the above embodiment, an example in which the coil storage portion 33 is formed on the side of the gear 3 in the vane rotor 7 has been shown, but it may be formed on the side opposite to the gear 3.
In the above-described embodiment, 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 is shown. The present invention may be applied to an apparatus.
In the above embodiment, the example in which the present invention is applied to the valve timing adjusting device attached to the intake-side camshaft C is shown. However, the present invention is applied to the valve timing adjusting device attached to the exhaust-side camshaft C. May be. In such a case, you may provide so that the vane rotor 7 may be locked to the most advanced angle side with a locking mechanism.
[0038]
In the above embodiment, the stopper pin 20 is moved in the front direction and fitted in the stopper hole 23a. However, the stopper pin 20 is moved in the rear direction and fitted in the stopper hole 23a. Alternatively, the stopper pin 20 may be moved so as to be fitted in the stopper hole 23a in the radial direction.
Moreover, although the example which accommodated the stopper pin 20 in the vane rotor 7 side was shown, the stopper pin 20 may be accommodated in the shoe housing 2 side, and the vane rotor 7 may be locked.
[0039]
In the above embodiment, an example in which three recesses 6 are formed in the shoe housing 2 and three vanes 12 are provided on the outer peripheral portion of the vane rotor 7 is shown. However, the number of recesses 6 and the number of vanes 12 are structurally different. Any number of recesses 6 and vanes 12 may be used as long as the number is one or more. 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. Four vanes 12 may be provided.
[0040]
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 be configured to rotate together 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 view showing the inside of a shoe housing.
FIG. 3 is a schematic explanatory diagram of a lock structure.
[Explanation of symbols]
C Camshaft (driven shaft)
2 Shoe housing 3 Gear 4 Plate 6 Recess 6a Advance chamber 6b Delay chamber 7 Vane rotor 12 Vane 29 Long hole (punching oil passage)
32 Torsion coil spring 33 Coil storage part 34 Advance oil path (oil path using coil storage part)

Claims (3)

A valve timing adjusting device provided in a driving force transmission system that transmits a driving force from a driving shaft of an internal combustion engine to a driven shaft that opens and closes a valve, and causes a phase difference in the rotation of the driven shaft with respect to the rotation of the driving shaft Because
This valve timing adjustment device
A shoe housing that rotates with one of the drive shaft or the driven shaft;
A vane rotor including a vane that rotates together with the other of the drive shaft or the driven shaft and divides a recess formed in the shoe housing into an advance chamber and a retard chamber;
A torsion coil spring that biases the vane rotor toward the advance side or the retard side with respect to the shoe housing;
The vane rotor is made of iron with excellent wear resistance,
Wherein all of the coil portions in the torsion coil spring, the valve timing control apparatus, characterized in that that will be accommodated in the coil receiving portion formed in the interior of the vane rotor. In the valve timing adjusting device according to claim 1,
The said valve | bulb accommodating part is utilized as a part of oil path connected with the said advance chamber or the retard chamber, The valve timing adjustment apparatus characterized by the above-mentioned. In the valve timing adjusting device according to claim 1 or 2,
On one surface in the axial direction of the shoe housing, a gear for driving the shoe housing is fixed with a plate interposed therebetween,
An oil passage is formed in the plate by punching, and the punching oil passage is sandwiched between the shoe housing and the gear and blocked from the outside.

Images