JPH04342810A - Oil feed device for hydraulically driven variable valve timing device - Google Patents

Abstract

PURPOSE:To cool lubricant oil by providing a lubricant oil feed passage led to a variable valve timing device, in the vicinity of a wall surface upon which running air impinges. CONSTITUTION:A variable valve timing mechanism 20 is disposed between an air-intake cam shaft and a timing pulley 20, and changes the valve timing by hydraulically changing the phases of the cam shaft and the crankshaft. A solenoid control valve 56 is incorporated for the directional control of lubricant oil so as to control the direction of hydraulic pressure applied upon the variable valve timing mechanism 20. A lubricant oil passage led to the solenoid control valve 56 is provided in the vicinity of an engine wall surface 10 in front of a vehicle. The stream (a) of lubricant oil fed to a hydraulic drive mechanism is cooled by running air as shown by A.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for supplying hydraulic oil to a hydraulic drive mechanism for changing valve timing in a hydraulically driven variable valve timing system for an internal combustion engine.

0002

[Prior Art] A hydraulic drive mechanism in which a hydraulic drive mechanism for controlling the relative phase between the camshaft and the crankshaft is provided between the camshaft and a power transmission member that transmits the rotation of the crankshaft to the camshaft. Variable valve timing devices are known. For example, JP-A-62-19
In the 1636 publication, helical teeth (splines) are installed between the camshaft and the timing pulley connected to the timing pulley on the crankshaft by a timing belt.
A ring gear is provided on the inner and outer peripheries, and this ring gear is engaged with a timing pulley and a camshaft, and this ring gear is moved by hydraulic pressure in a direction parallel to the axis of the camshaft. As the ring gear moves, the timing pulley and camshaft are rotated relative to each other via the helical spline, making it possible to vary the valve timing.

0003

In order to change the valve timing, a hydraulic oil, for example a lubricating oil for lubricating an internal combustion engine, is supplied to the hydraulic drive mechanism. That is, lubricating oil is supplied from the oil pan to the hydraulic drive mechanism by the oil pump. However, since the lubricating oil is not forcibly cooled, the temperature of the lubricating oil flowing into the hydraulic mechanism tends to rise, and the high temperature of the lubricating oil reduces the viscosity of the lubricating oil, causing the lubricating oil in control valves, etc. There is a problem that the amount of leakage increases and the responsiveness deteriorates. It is of course possible to install an independent lubricant cooling system in the engine body for the lubricant supply passage in order to lower the temperature of the lubricant, but this is disadvantageous in terms of both cost and installation space. Not even. An object of the present invention is to provide a configuration that can effectively reduce the temperature of hydraulic oil supplied to a hydraulic drive mechanism without using a special cooling device.

0004

[Means for Solving the Problems] According to the present invention, a hydraulic drive mechanism for controlling the relative phase between the camshaft and the crankshaft is connected to the camshaft and a power source for transmitting the rotation of the crankshaft to the camshaft. An internal combustion engine characterized in that, in a hydraulically driven variable valve timing device provided between a transmission member and a hydraulically driven variable valve timing device, a passage for supplying hydraulic oil for driving hydraulic pressure to a hydraulic drive mechanism is provided near an outer wall on the front side of the engine. A refueling system for a hydraulically driven variable valve timing device is provided.

[0005]

[Operation] Since the hydraulic pressure for the hydraulic drive mechanism passes through the supply passage near the outer wall on the front side of the engine, it is cooled by the running wind and the temperature of the hydraulic oil is lowered. Therefore,
Leakage of lubricating oil during valve timing control is reduced,
Responsiveness can be improved.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, 10 schematically indicates a cylinder head of a DOHC type internal combustion engine, and 12 schematically indicates a camshaft cover. In this case, the internal combustion engine is placed horizontally. Therefore, the wind from the vehicle hits the engine body from the side as shown by arrow A. Reference numeral 14 indicates a timing pulley for driving the intake camshaft, and reference numeral 16 indicates a timing pulley for driving the exhaust camshaft.
4 and 16 are wound around a timing pulley on a crankshaft (not shown) via a timing belt 18. Although not shown, the timing pulleys 14 and 16 and the timing belt 18 are covered by a timing belt cover. A variable valve timing mechanism 20 is provided between the intake camshaft timing pulley 14 and the intake camshaft. This variable valve timing mechanism 20 will be explained in detail with reference to FIG. 2. The timing pulley 14 is rotatably fitted to one end of an intake cam driving camshaft 22. A cup-shaped member 24 is rotatably fitted to the timing pulley 14 at its outer circumferential portion 24A, and a center boss portion 24B of the cup-shaped member 24 is fitted to a small diameter portion at the end of the camshaft 22, and the cup is connected to the timing pulley 14 by a bolt 28. The shaped member 24 is integrally connected to the camshaft 22. The ring gear 30 is disposed between the cup-shaped member 24 and the central boss portion 32 of the timing pulley 14. As is well known, the ring gear 30 has helical teeth 30 - 1 and 30 - 2 formed on its outer and inner peripheries, and the outer helical teeth 30 - 1 are helical teeth formed on the inner periphery of the cup-shaped member 24 . The helical teeth 30-2 on the inner circumference are engaged with the shaped teeth 34.
meshes with helical teeth 40 formed on the boss portion 32 of the timing pulley. Therefore, by moving the ring gear 30 in a direction parallel to the axis of the camshaft, the relative rotational angular position between the timing pulley 14 and the cup-shaped member 24, that is, the camshaft 22, is changed.
Valve timing can be changed.

The ring gear 30 has a U-shaped cross section, and has an annular groove 44 formed therein, and a spring 46 between the bottom surface of the annular groove 44 and the hub portion of the timing pulley 14.
is arranged, and this spring 46 moves the ring gear 30 toward the left side in the figure, so that the bottom surface of the ring gear 30 is aligned with the cup-shaped member 24.
It is biased so that it moves to the position where it hits the opposite bottom surface of the. When the ring gear 30 is in this position, the valve timing is at the normal timing, and by moving the ring gear 30 to the right in the figure against the spring 46, the valve timing is changed from the normal timing. A hydraulic chamber 48 is provided between the opposing surfaces of the ring gear 30 and the cup-shaped member 24.
is formed, and the ring gear 3 is activated by the hydraulic pressure in the hydraulic chamber 48.
0 said movements can be induced.

The ring gear 30 has an inner circumferential surface 30a in close contact with the opposing outer circumferential surface of the boss portion 32 of the timing pulley 14, an outer circumferential surface 30b in close contact with the opposing inner circumferential surface of the cup-shaped member 24, and these contact surfaces The hydraulic chamber 48 is being sealed.

Next, the configuration of the hydraulic system to the hydraulic chamber 48 will be explained. A lubricating oil passage 50 is formed in the camshaft 22, and lubricating oil is introduced and discharged through this passage 50. The passage 50 is connected to an electromagnetic control valve 56 via a passage 52 formed in the cylinder head 10. The electromagnetic control valve 56 is attached to the front side wall of the cylinder head 10, as shown in FIG. The electromagnetic control valve 56 is the valve body 6
0, a cylindrical sliding valve 62 inside the valve body 60, and an electromagnetic actuator 64.The electromagnetic actuator 64 is connected to a control circuit 67, and the actuator 64 is driven according to the engine operating conditions. It is possible to obtain valve timing according to the The control valve 56 is a three-port valve that includes an annular common port 68, an annular first switching port 70, and a second axial switching port 72, and when the actuator 64 is turned on, the state, the common port 68 is communicated with the annular first switching port 70 via the annular groove 74,
Lubricating oil from the first switching port 70 passes through the common port 68 and is introduced into the hydraulic chamber 48 through the passages 52, 50 as indicated by the solid arrow X, the ring gear 30 is moved against the spring 46, and the valve timing is adjusted. The normal value will be changed. When the actuator 64 is turned off, the state shown in the lower part of FIG. 2 is assumed, and the common port 68 is connected to the annular groove 7.
4. It communicates with the second switching port 72 through the center hole 76, and the hydraulic pressure from the hydraulic chamber 48 flows through the passage 50 as indicated by the broken line arrow Y.
, 52 through the common port 68, the groove 74, and the center hole 76, and is discharged from the second switching port 72, and the ring gear 30 is pushed back by the spring 46, and the valve timing is set to the normal value.

In FIG. 1, the flow of hydraulic pressure is schematically shown by broken line arrows, and the lubricating oil from the oil pan is sent upward from the hydraulic pump (not shown) to the electromagnetic control valve 5 as shown by arrow a.
6 is introduced into the first switching port 70 of No.6. In Figure 3,
A hydraulic passage 80 is formed vertically in the cylinder head 10, lubricating oil from the hydraulic pump is introduced into the passage 80 from the cylinder block side, and horizontal passages 82, 84
is introduced into the annular first switching port 70 of the control valve 56. Reference numeral 94 in FIG. 3 indicates a mounting hole for the control valve 56;
When the control valve 56 is attached, the passage 84 communicates with the switching port 70. When the electromagnetic control valve 56 is turned on, hydraulic pressure is taken out from the common port 68 in FIG. 2 in the horizontal direction as indicated by arrow b in FIG. That is, in FIG. 3, a passageway 86 is drilled into the cylinder head 10 in alignment with the annular common port 68 of the control valve. The hydraulic pressure taken out to the passage 86 passes through a substantially horizontal passage 88 shown in FIG.
arrow c) in Figure 4, passing through passage 90 in Figure 4 (arrow d in Figure 1
), from the passage 52 (arrow e in Figure 1), the camshaft 22
The ring gear 30 is introduced into the hydraulic chamber 48 through a passage 50 therein, and the ring gear 30 is driven against the spring 46 to switch the valve timing. When returning the valve timing to the normal position, the control valve 56 is turned off and the hydraulic chamber 48 is turned off.
Hydraulic pressure is released in the direction opposite to the passages 50, 52, 90, 88, and 86, enters the electromagnetic control valve 56 through the common port 68, and is released from the port 72 as indicated by arrow f in FIG. That is, as shown in FIG.
4, the port 72 is connected to the cylinder head 10.
It opens into a space 98 inside, and lubricating oil is discharged toward the oil pan as indicated by arrow f.

According to an embodiment of the present invention, as shown in FIG. 1, lubricating oil is supplied to the electromagnetic control valve 56 at the side wall of the horizontally mounted engine, which is the surface directly exposed to the engine running air. That is, the passages 80 and 82 constituting the supply passage for lubricating oil to the electromagnetic control valve 56 are provided near the side wall 100 facing the front of the vehicle, which is directly exposed to the traveling wind in the cylinder head. Therefore, the temperature of the lubricating oil to the control valve 56 can be maintained low and the viscosity can be maintained appropriately low, which reduces the leakage of lubricating oil from the seal surfaces 30a and 30b of the piston and improves control responsiveness. can be increased.

In FIGS. 3 and 4, the lubricating oil passages 80, 88, etc. to the variable valve timing mechanism pass near the cooling water jackets 102, 102' of the engine body, so they may be cooled from there. can. In the case of the embodiment, lubricating oil does not flow through the control valve 56 under normal conditions, and the lubricating oil is introduced to the hydraulic chamber 48 only when switching the valve timing, so the lubricating oil does not flow into the control valve 56 before control. The lubricating oil is stored in the passages 80 and 82, and since there is no flow, the temperature of the lubricating oil can be efficiently lowered by the wind. During control, this stored lubricating oil whose temperature has dropped is introduced into the hydraulic chamber 48 via the control valve 56. Therefore, high control responsiveness can be obtained.

[0013]

According to the present invention, the temperature of the lubricating oil to the hydraulic mechanism is lowered by providing the passage for supplying the lubricating oil to the hydraulic drive mechanism close to the outer wall surface on the front side of the vehicle. Responsiveness can be improved by preventing the fluidity of the hydraulic oil from increasing too much and by reducing the leakage of lubricating oil during valve timing switching.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an internal combustion engine equipped with a variable valve timing mechanism, and the flow of hydraulic oil to a hydraulic mechanism for variable valve timing is indicated by broken lines.

FIG. 2 shows a cross-sectional view of the variable valve timing mechanism, and shows the flow of hydraulic pressure in each state of the control valve using solid lines and broken lines.

FIG. 3 is a sectional view taken along line III-III in FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV in FIG. 1;

[Explanation of symbols]

10...Cylinder head 14...Intake camshaft timing pulley 20...Variable valve timing mechanism 22...Intake camshaft 30...Ring gear 46...Spring 48...Hydraulic chambers 50, 52...Lubricating oil passage 56...Solenoid control valve 64...Actuator 68... Common port 70...first switching port 72...second switching port

Claims (1)

[Claims] Claim 1: A hydraulic drive in which a hydraulic drive mechanism for controlling the relative phase between the camshaft and the crankshaft is provided between the camshaft and a power transmission member that transmits rotation of the crankshaft to the camshaft. 1. A refueling device for a hydraulically driven variable valve timing device, characterized in that a passage for supplying hydraulic oil for driving hydraulic pressure to a hydraulic drive mechanism is provided near an outer wall on the front side of an engine.