JPH0212253Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a hydraulic lash adjuster that automatically absorbs changes in the valve gap between the cam and the intake/exhaust valves and always maintains a zero gap. This invention relates to a lubricating oil supply device for an engine.

(Prior art) Conventionally, this type of lubricating oil supply device uses a hydraulic latch adjuster, a so-called hydraulic tappet, between a cam and an intake/exhaust valve, as described in Japanese Patent Application Laid-Open No. 56-83508. There is a known device that automatically absorbs changes in the valve gap to maintain a zero gap at all times and prevent the occurrence of seating noise.

This lubricating oil supply device includes a discharge side of an oil pump that sucks lubricating oil from the oil pan,
A pressure regulator is interposed between the oil pan and the lubricating oil main line to keep the lubricating oil supply pressure constant.

However, during cold periods such as winter, the viscosity of the lubricating oil increases during warm-up of the engine (cold time), and even if the pressure regulator mentioned above opens, the high viscosity lubricating oil remains. Because the oil cannot be sufficiently drained from the regulator to the oil pan, a so-called pump-up phenomenon occurs in which the main line for supplying lubricating oil reaches a high pressure higher than the set pressure.As a result, the reserve chamber of the hydraulic latch adjuster becomes under high pressure, causing the check valve to close. There is a problem in that when the ball is pushed open, lubricating oil in the reserve chamber flows into the pressure chamber, pushing down the cylinder and opening the intake/exhaust valves when they are not opening. This is particularly noticeable when the engine is started, and there has been a problem in that the opening and closing timings of the intake and exhaust valves are shifted when the engine is cold.

(Purpose of the invention) This invention maintains the proper opening/closing timing of the intake and exhaust valves without causing the hydraulic lash adjuster to malfunction, even when the viscosity of the lubricating oil increases, especially when it is cold. The purpose of the present invention is to provide a lubricating oil supply device for an engine equipped with a hydraulic lash adjuster.

(Structure of the invention) This invention is an engine lubricating oil supply device configured to automatically adjust the clearance between a cam and an intake/exhaust valve using a hydraulic lash adjuster. A first pressure regulator that adjusts the pressure is provided in the lubricating oil supply device connected to the discharge side of the oil pump, and a lubricating oil supply passage downstream of the first pressure regulator is provided. , and at the entrance of the lubricating oil passage for the hydraulic lash adjuster located downstream of the branching point to the crank system lubricating oil passage, the opening pressure is lower than that of the first pressure regulator, and a relief passage is provided. The present invention is characterized in that it is a lubricating oil supply device for an engine equipped with a hydraulic latch adjuster, which is provided with a second pressure regulator that opens into the crank chamber.

(Effect of the invention) According to this invention, since the above-mentioned second pressure regulator is provided, the pressure in the main lubricating oil supply line is reduced due to the increase in the viscosity of the lubricating oil when the engine is cold. Even if the pressure becomes higher than the set pressure of the first pressure regulator, the second pressure regulator suppresses the increase in circuit pressure after the regulator to prevent malfunction of the hydraulic lash adjuster. As a result, the opening and closing timing of the intake and exhaust valves can be maintained appropriately.

Moreover, the relief passage of the second pressure regulator mentioned above opens into the crank chamber, which is not affected by oil pressure changes due to the viscosity of the lubricating oil, so the pressure can be adjusted to a constant absolute value and the engine cools down. It is possible to reliably prevent the pressure of the hydraulic lash adjuster from increasing due to high viscosity during temporary periods.

In addition, since the above-mentioned second pressure regulator is installed downstream of the branch point to the crank system lubricating oil path, when the second pressure regulator operates, there is no damage to the crank system. Sufficient lubricating oil can be supplied by the set pressure of the first pressure regulator (or higher pressure when cold), and wear due to lack of oil film can be prevented.

(Example) An example of this invention will be described in detail below based on the drawings.

The drawing shows a lubricating oil supply system for an engine with a hydraulic latch adjuster. In FIG. It is a valve for

This exhaust valve 1 is formed so that its stem 4 moves up and down along a stem guide 5, and the upper part of the stem 4 is led out into a tappet fitting chamber 6 in the cylinder head 2, and is divided into a stem head 7. A spring retainer 9 (so-called spring receiver) is fitted through the collet 8, and a valve spring consisting of a double coil spring is installed between the lower surface of the spring retainer 9 and the spring seat 6a of the tapepet fitting chamber 6. 10 is attached.

A camshaft 13 is rotatably mounted horizontally above the above-mentioned tappet fitting chamber 6 using a cylinder head rib 11 and a bearing 12 screwed onto this rib 11. A cam 14 is integrally formed.

A hydraulic latch adjuster 15 is interposed in the tappet fitting chamber 6 between this cam 14 and the above-mentioned exhaust valve 1.
The structure is such that changes in the clearance between the lash adjuster and the cam 14, so-called tappet clearance, are automatically absorbed to maintain zero clearance at all times.

That is, the hydraulic lash adjuster 15
includes a body 17 whose upper end is always in contact with the circumferential surface of the cam 14 and which moves up and down within the sliding hole 16 as the cam 14 rotates; and a sliding guide 1 within this body 17.
8, a cylinder 19 whose lower end is always in contact with the aforementioned stem head 7, a plunger 20 interposed within the cylinder 19, a check ball gauge 21 on the lower surface of this plunger 20, and the aforementioned cylinder. 19, the plunger spring 22 stretched between the reserve chamber 23 and the pressure chamber 2
A check valve ball 25 that opens and closes the bottom opening of the plunger 20 as appropriate depending on the pressure difference between the lubrication passages 2 and
The above-mentioned reserve chamber 23 and pressure chamber 24 are always filled with lubricating oil supplied from 6 and 27, and the above-mentioned change in tappet clearance is automatically absorbed to maintain zero clearance at all times. .

Although the exhaust side is illustrated in Fig. 1,
The intake side is also configured in the same way.

Next, the configuration of the lubricating oil supply hydraulic circuit from the oil pan 28 to the hydraulic lash adjuster 15 will be described based on FIG. 2.

A lubricating oil supply main line 30 is connected to the discharge side of the oil pump 29, and this main line 30 has
The first part adjusts the pressure of lubricating oil supplied to the engine.
A pressure regulator 31 is provided.

Further, an oil passage 33 (crank system lubrication oil passage) that supplies lubricating oil to the crankshaft 32 in the cylinder block is branched from the above-mentioned main stream line 30, and a branch point 34 to this crank system lubrication oil passage is branched. A second pressure regulator 35 is connected to the side and to the inlet side of the lubrication passage 26 for the hydraulic lash adjuster.

The second pressure regulator 35 has a valve opening pressure set to a lower pressure than the first pressure regulator 31, for example, the valve opening pressure of the first pressure regulator 31. to about 4Kg/cm ² and the opening pressure of the second pressure regulator 35 to about 3Kg/cm2.
Each is set to Kg/cm ² .

And the above-mentioned second pressure regulator 35
The specific structure of is shown in FIG.

That is, a back pressure chamber 37 is formed in the main flow line 30 through the primary port 36, a spring 38 and a valve 39 are interposed in this back pressure chamber 37, and the valve 39 is constantly pressed against the valve seat 40 by the spring 38. However, when the primary port 36 is closed by the valve 39 and the lubricating oil pressure in the main line 30 becomes greater than the force of the spring 38, the valve 39 is closed against the spring 38.
9 opens the valve to the left in Fig. 3, and the primary port 3
6 is communicated with the secondary port 41, and the back pressure chamber 37
A drain passage 42, which is in constant communication with the oil pan 28, and the above-mentioned secondary port 41 are merged in a relief passage 43, and this return fluid is returned to the above-mentioned oil pan 28.

In other words, this second pressure regulator 35
The relief passage 43 opens into the crank chamber where the oil pressure does not change due to the viscosity of the lubricating oil, and can be adjusted to a constant absolute pressure value.

The operation of the lubricating oil supply system for an engine with a hydraulic lash adjuster configured as described above will be explained below.

When the engine is started when the engine is cold, the oil pump 29 rotates in conjunction with this, sucks up the lubricating oil A in the oil pan 28 through the strainer 44, and releases it from the outlet of the oil pump 29 into the above-mentioned main stream. Discharge to line 30, each element 33, 26, 27
and is supplied to each lubricated part via the oil passage 45.

When the pressure in the above-mentioned main stream line 30 becomes higher than the set pressure of the first pressure regulator 31, the regulator 31 opens, but the lubricating oil has a high viscosity because it is cold. , the oil is not sufficiently discharged from the regulator 31 to the oil pan 28, and the pressure in the main line 30 becomes equal to or higher than the set pressure value of the first pressure regulator 31.

However, downstream of the first pressure regulator 31, more specifically, further downstream of the branch point 34 downstream of the first pressure regulator 31, there is a second pressure regulator with a low pressure setting.
Since the pressure regulator 35 is connected, the high viscosity lubricating oil flowing through the main line 30 in the direction of arrow a in FIG.
8 to the left to communicate between the primary port 36 and the secondary port 41 at a predetermined opening corresponding to the set pressure of the spring 38.
The relief fluid from 6, 41 flows back to the oil pan 28 through the relief passage 43 as shown by arrow b in FIG.
Since lubricating oil at a predetermined pressure set by the regulator 35 is supplied to the downstream side of the hydraulic lash adjuster 15, no high pressure is applied to the reserve chamber 23 of the hydraulic lash adjuster 15. Star 1
5 does not malfunction, so it can follow the movement of the cam 14 and maintain zero clearance, and as a result,
The opening and closing timing of intake and exhaust valves can be maintained appropriately.

Here, the above-mentioned second pressure regulator 3
Since the relief passage 43 of No. 5 opens into the crank chamber where the oil pressure does not change due to the viscosity of the lubricating oil,
It can be adjusted to a constant absolute pressure value, and it is possible to reliably prevent the hydraulic lash adjuster 15, so-called HLA, from increasing in pressure due to high viscosity when the engine is cold.

In addition, the above-mentioned second pressure regulator 3
5 is provided on the downstream side of the branch point 34 to the crank system lubricating oil path, that is, the oil path 33, so when the second pressure regulator 35 is operated, the first pressure regulator 35 is connected to the crank system. Since sufficient lubricating oil can be supplied by the set pressure of the generator 31 (or a higher pressure when it is cold), it is possible to prevent wear due to lack of oil film in the crank system.

FIG. 4 shows another embodiment, in which the camshaft 13
A dedicated oil passage 45' for supplying lubricating oil to the bearings 12, 12, . The above-mentioned hydraulic lash adjuster lubrication passage 26,
27, and the aforementioned second pressure regulator 35 is connected to the entrance side of this passage 26, and only the part downstream of the connection position of the regulator 35 is configured to be controlled by the set pressure of the regulator 35. There is.

With this configuration, the hydraulic latch adjuster 15 can follow the movement of the cam 14 and maintain a zero clearance without any malfunction as described above, and in addition, the hydraulic latch adjuster 15 can maintain zero clearance by following the movement of the cam 14. ..., etc., the second pressure regulator 3
It is possible to supply lubricating oil at a pressure higher than the set pressure of 5.

In short, even if the pressure in the main lubricating oil supply line becomes higher than the set pressure of the first pressure regulator 31 due to the increased viscosity of the lubricating oil when the engine is cold, the second pressure regulator 31 The shear regulator 35 can suppress the increase in circuit pressure, which has the effect of preventing the hydraulic lash adjuster 15 from malfunctioning and always maintaining the proper opening/closing timing of the exhaust valve 1. .

Moreover, the second pressure regulator 3 mentioned above
Since the relief passage 43 of No. 5 opens into the crank chamber where the oil pressure does not change due to the viscosity of the lubricating oil,
The absolute pressure can be adjusted to a constant value, and it is possible to reliably prevent the hydraulic lash adjuster 15 from increasing in pressure due to the high viscosity of the oil when the engine is cold.

In addition, the second pressure regulator 3 described above
5 is provided on the downstream side of the branch point 34 to the crank system lubricating oil path, so when the second pressure regulator 35 is operated, the first pressure regulator 31 is connected to the crank system. Sufficient lubricating oil can be supplied at the set pressure (or higher pressure when cold), which has the effect of preventing wear due to lack of oil film in the crank system.

In the correspondence between the configuration of this invention and the embodiment described above, the lubricating oil supply passage of this invention is the main flow line 30 and the lash adjuster dedicated passage 46 of the embodiment.
Similarly, the crank system lubricating oil passage corresponds to the oil passage 33, but this invention is not limited to the configuration of the above-described embodiment.

In the above embodiment, the hydraulic lash adjuster 15 is provided between the exhaust valve 1 and the cam 14, but it goes without saying that this may also be applied to the intake valve.

[Brief explanation of the drawing]

The drawings show one embodiment of this invention, in which Fig. 1 is a sectional view of a lubricating oil supply system for an engine with a hydraulic latch adjuster, Fig. 2 is a hydraulic circuit diagram of the lubricating oil supply system, and Fig. 3 is a sectional view of a lubricating oil supply system for an engine with a hydraulic latch adjuster. 2 is a sectional view of the pressure regulator, and FIG. 4 is a hydraulic circuit diagram showing another embodiment of the lubricating oil supply device. DESCRIPTION OF SYMBOLS 1...Exhaust valve (intake valve), 14...Cam, 15...Hydraulic type latch adjuster, 26...Lubricating passage for hydraulic type latch adjuster, 29...Oil pump, 3
0... Mainstream line, 31... First pressure regulator, 33... Oil path (crank system lubricating oil path), 34
... Branch point, 35... Second pressure regulator,
43...Relief passage, 46...Lush adjuster exclusive passage.

Claims (1)

[Scope of Claim for Utility Model Registration] An engine lubricating oil supply device configured to automatically adjust the clearance between a cam and intake/exhaust valves using a hydraulic latch adjuster, A first pressure regulator for adjusting pressure is provided in a lubricating oil supply passage connected to the discharge side of the oil pump, and in a lubricating oil supply passage downstream of this first pressure regulator, In addition, at the entrance of the lubricating oil passage for the hydraulic latch adjuster on the downstream side of the branch point to the crank system lubricating oil passage, the opening pressure is lower than that of the first pressure regulator, and the relief passage is connected to the crank system. A lubricating oil supply device for an engine with a hydraulic latch adjuster, which is equipped with a second pressure regulator that opens into a chamber.