JP2587130B2 - Valve timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a valve opening / closing timing control device, and is used for, for example, a general valve gear of an internal combustion engine.

(Prior Art) The prior art relating to the present invention is described, for example, in Japanese Patent Application No. 1-61820 filed by the present applicant.

FIG. 4 is a sectional view of a prior art valve timing control apparatus 100.

The camshaft 120 is rotatably supported by the engine body 110. Oil passage 1 inside camshaft 120
30 are provided. A timing pulley 160 is fitted around the outer periphery of the camshaft 120 (left side in the figure), and the outer periphery of the timing pulley 160 has a groove 160a. Also, the camshaft 120 is covered so as to cover the timing pulley 160.
On the left end of the drawing, a damper case 150
Are arranged. The damper case 150 and the timing pulley 160 are engaged by respective labyrinth grooves 150a and 160b, thereby forming a viscous damper having a viscous fluid therein.

On the left side of the damper case 150 in the figure, a cover 180 is provided so as to cover the viscous damper means, and its outer peripheral portion is engaged with a part of the timing pulley 160. The viscous fluid sealed in the viscous damper means includes an oil seal 190 disposed between the cover 180 and the damper case 150, an O-ring 200 disposed between the cover 180 and the timing pulley 160, An oil seal 210 disposed between the damper case 150 and the timing pulley 160 prevents the oil from leaking.

A cylindrical groove 22 is provided between the inner peripheral portion of the damper case 150 and the outer peripheral portion of the cam shaft contact portion 160c of the timing pulley 160.
A piston means 220 having a groove 2 is provided.
A spring 230 that urges the piston means 220 to the left in the drawing is provided in the inside of 20a.

Helical spline 1 on the inner periphery of damper case 150
50b is formed and the piston means 220 is engaged with it.
A helical spline 220b is formed on the outer peripheral portion of. A helical spline 220c is formed on the inner periphery of the piston means 220, and a helical spline 160d is formed on the inner periphery of the camshaft contact portion 160c of the timing pulley 160 so as to mesh with the helical spline 220c.

A hydraulic chamber 240 is formed by the inner peripheral portion of the damper case 150, the top of the piston means 220, and the inner peripheral portion of the camshaft contact portion 160c of the timing pulley 160. The hydraulic chamber 240 communicates with the oil passage 130 in the camshaft 120.

A ring 250 and a bolt 260 are screwed to the camshaft 120 from the left side of the damper case 150 in the drawing to prevent the damper case 150 and the like from coming off from the camshaft 120.

In the above configuration, when the engine starts and the crankshaft (not shown) rotates, the rotation is transmitted to the timing pulley 160. During normal running, the rotational torque is applied to the timing pulley 160, the helical spline 160d of the timing pulley 160, and the helical spline 2 of the piston means 220.
Helical spline 150 of 20c, 220b, damper case 150
b, damper case 150, knock pin 140, camshaft 1
It is communicated as 20.

If it is desired to advance the valve opening / closing timing of an engine (not shown) from the state during the normal running, oil is supplied to the oil passage 130 to increase the volume of the hydraulic chamber 240. That is, the piston means 220 moves to the right in the figure overcoming the biasing force of the spring means 230 to the left in the figure. Then the piston means
The camshaft 120 integrated with the damper case 150 is formed by the helical spline 150b of the damper case 150 and the helical spline 160d of the timing pulley 160 that respectively engage with the helical splines 220b and 220c on the inner and outer circumferences of the 220.
Rotates relatively to the timing pulley 160 to advance the valve opening / closing timing of an engine (not shown).

When the valve opening / closing timing of the engine (not shown) is returned from this state, the supply of oil to the oil passage 130 is stopped, and the volume of the hydraulic chamber 240 is reduced. That is, the piston means 220 moves leftward in the figure due to the urging force of the spring means 230 leftward in the figure. Then, the piston means 22
The camshaft 120 integrated with the damper case 150 is formed by the helical spline 150b of the damper case 150 and the helical spline 160d of the timing pulley 160 which respectively engage with the helical splines 220b and 220c on the inner and outer circumferences of FIG.
Rotates relative to the timing pulley 160 to return the valve opening / closing timing of the engine (not shown).

In this manner, the valve opening / closing timing can be continuously controlled by the amount of oil supplied to the hydraulic chamber 240.

The camshaft 120 receives a fluctuating torque from a spring engaged with a valve (not shown) during operation of the engine.
The fluctuating torque is transmitted to the helical splines 150b, 220b, 220c, and 160d via the damper case 150, causing a hitting sound due to the back crash of the helical splines 150b, 220b, 220c, and 160d, and the negative of the fluctuating torque. The component tends to move the piston means 220 rightward in the figure. Then, since the labyrinth groove 150a formed in the damper case 150 integrated with the camshaft 120 and the labyrinth groove 160b formed in the timing pulley 160 rotate relative to each other, the viscous fluid sealed in the viscous damper means 170 (for example, A large shear force acts on the silicon oil) to absorb the fluctuating torque.

(Problems to be Solved by the Invention) In the above-mentioned prior art, when it is desired to advance the valve opening / closing timing of the engine, when hydraulic pressure is supplied to the hydraulic chamber 240 via the oil passage 130, the piston means returns. The camshaft moves rightward in the figure against the spring, whereby the camshaft rotates relative to the timing pulley via the helical spline, and the valve opening / closing timing of the engine can be advanced. However, at this time, if the piston means is fully moved rightward in the drawing, the following problem may occur. That is, when the piston means fully moves to the right, the bottom 270 of the skirt of the piston comes into close contact with the wall 160e of the timing pulley. Then, from the hydraulic chamber 240, the helical spline 150b of the damper case 150 and the helical spline 220b of the piston means 220
The oil which has entered the gap between the seal member 210 and the damper case reaches the seal member 210 through the gap S between the timing pulley and the damper case. In such a state, the sealing member 21
Unexpectedly high hydraulic pressure is applied to zero, which may cause problems such as breakage of the seal member 210 and poor durability. Also, because there is no oil escape part, oil to be returned to the drain side stays,
There was a problem that the response at the time of operation OFF was reduced.

Therefore, according to the present invention, even if the piston means is fully moved to the right and the bottom 270 of the skirt of the piston comes into close contact with the wall 160e of the timing pulley, the helical spline 150b of the damper case 150 and the piston The oil that has entered the gap between the helical spline 220b of the means 220 flows out of the flow path formed at the bottom of the skirt portion of the piston into the vacant space behind the piston means to prevent stagnation of the oil, It is intended to prevent damage.

[Configuration of the invention]

(Means for Solving the Problems) Therefore, the present invention provides a timing pulley rotatably provided around a camshaft, and a damper fixed to a tip of the camshaft and forming a space between the timing pulley and the damper. A case, a piston having a skirt for transmitting a driving force from the timing pulley to the camshaft via a damper case, a passage for sucking and discharging oil in a hydraulic chamber at one end of the piston, and another end of the piston A spring housed in a skirt of a piston arranged to bias the piston toward the initial position in the empty room, and a seal arranged between the timing pulley and the damper case on the empty room side An oil recovery passage for discharging oil flowing into the empty chamber from the hydraulic chamber;
It comprises a skirt outer peripheral side provided at the bottom of the skirt on the side close to the seal and a flow path communicating with the space inside the skirt, and this is a means for solving the problem.

(Effect) Even if the piston means provided in the valve timing control device is fully moved rightward and the bottom of the skirt portion of the piston comes into close contact with the wall of the timing pulley, the helical of the damper case is removed from the hydraulic chamber. Oil that has entered the gap between the spline and the helical spline of the piston means flows out behind the piston means from a flow path formed at the bottom of the skirt portion of the piston. This can prevent breakage of the seal member and increase the durability of the seal member.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a valve timing control apparatus of the present invention,
FIG. 2 is a front view of the bottom surface of the skirt portion of the piston, and FIG. 3 is a view taken in the direction of arrow B in FIG.

In FIG. 1, 1 is a timing pulley, 2 is a damper case, 3 is a piston means, 4 is a knock pin, 5 is a fixing bolt, 6 is a return spring, 7 is a camshaft, 8 is a labyrinth groove, 9 is an oil passage, 11 Is a hydraulic chamber, and 12 is a seal member. These constitute a valve opening / closing timing control device having the same structure as a conventional valve opening / closing timing control device. Since the overall structure and operation of the valve timing control device are the same as those of the conventional valve timing control device described above, detailed description thereof will be omitted.

In FIG. 1, the timing pulley 1,
An empty space 20 is formed behind the piston means by the three members of the damper case 2 and the piston means 3 as in the conventional valve timing control apparatus. The vacant space 20 is communicated with an oil discharge passage via a passage 21, and the oil leaking into the vacant space 20 is drained from here. A notch 32 as a flow path as shown in FIG. 2 is formed in the bottom 31 of the piston skirt as the piston means. Further, a seal member 12 is disposed between the damper case 2 and the timing pulley 1.

In the valve opening / closing timing control device having the above configuration, when hydraulic pressure is supplied to the hydraulic chamber 11 through the oil passage 9 in order to advance the valve opening / closing timing of the engine, the piston means moves rightward in the drawing by the hydraulic pressure. At this time, when the piston means is fully moved rightward and the bottom 31 of the skirt of the piston comes into close contact with the wall 1e of the timing pulley, the helical spline of the damper case and the helical spline of the piston means are moved from the hydraulic chamber. The oil that has entered the gap tries to reach the seal member 12 through the gap S between the timing pulley and the damper case as it is. However, there is a notch at the bottom of the piston skirt as a piston means.
Is formed, the oil that has entered the gap between the helical spline of the damper case 2 and the helical spline of the piston means 3 flows out through the notch 32 into the vacant space 20 behind the piston means. It does not reach the member. Thereby, the high-pressure oil pressure for operating the piston means reaches the seal member, and does not damage the seal member or reduce the durability of the seal member. In this embodiment, an example in which a notch is provided at the bottom of the piston as a flow path has been described. However, any flow path may be used as long as it has a function of allowing oil to flow out.

〔The invention's effect〕

According to the present invention, the oil that has entered the gap between the helical spline of the damper case and the helical spline of the piston means from the hydraulic chamber flows out of the flow path formed at the bottom of the skirt portion of the piston into the empty chamber behind the piston means. Accordingly, it is possible to prevent the accumulation of oil and prevent the seal member from being damaged by the high-pressure hydraulic pressure and from deteriorating the durability of the seal member.

[Brief description of the drawings]

1 is a sectional view of a valve timing control apparatus according to an embodiment of the present invention, FIG. 2 is a front view of a bottom surface of a skirt portion of a piston,
FIG. 3 is a view taken in the direction of arrow B in FIG. 2, and FIG. 4 is a sectional view of a conventional valve timing control apparatus. Description of main parts in the drawing 1 timing pulley 2 damper case 3 piston means 4 knock pin 5 fixing bolt 6 return spring 7 camshaft 8 labyrinth groove 9 …… Oil passage, 11… Hydraulic chamber 12 …… Seal member, 20 …… Vacancy 21 …… Path 31 …… Bottom part of piston skirt part 32 …… Flow path

Continuing from the front page (72) Inventor Junichi Kano 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. ) Inventor Nobuyuki Murakami 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (56) References JP-A-2-241914 (JP, A) JP-A-2-227507 (JP, A)

Claims (1)

(57) [Claims] A timing pulley rotatably provided around a camshaft; a damper case fixed to a tip of the camshaft to form a space between the timing pulley; and a damper case from the timing pulley. A piston having a skirt for transmitting a driving force to a camshaft via a piston, a passage for sucking and discharging oil in a hydraulic chamber at one end of the piston, and moving the piston to an initial position in an empty chamber at the other end of the piston A spring housed in a skirt of a piston arranged to urge the seal, a seal arranged between the timing pulley and the damper case on the vacant chamber side, An oil recovery passage for discharging the inflowing oil, a skirt outer peripheral side provided inside the skirt bottom near the seal and an inside of the skirt. Flow path and valve timing control apparatus comprising a communicating space.