JPS63170510A - Valve system for internal combustion engine - Google Patents

Abstract

PURPOSE:To avoid the operation delay by providing a heater on an oil passage between an oil gallery and a cam follower connection switching mechanism. CONSTITUTION:An oil passage 39 between an oil gallery 37 feeding the lubricating oil to various sections of an engine and a connection switching mechanism 10 switching the connection and disconnection of cam followere 7, 8, 9 is connected to an oil pressure feeding source 38 in common. A heater 47 is provided on the oil passage 39 between the oil gallery 37 and the connection switching mechanism 10. Accordingly, the operating oil is heated to improve its fluidity at a low temperature, and the operation delay can be avoided.

Description

Detailed Description of the Invention A0 Object of the Invention (1) Industrial Application Field The present invention provides a connection switching mechanism between a plurality of cam followers that switches connection and disconnection of the cam followers according to the action of hydraulic pressure. The present invention relates to a valve train for an internal combustion engine in which an oil gear for supplying lubricating oil to various parts of the engine and an oil passage connected to a connection switching mechanism are commonly connected to a hydraulic pressure supply source.

(2) Prior Art Conventionally, such a valve train has been developed, for example, in Japanese Patent Application Laid-Open No. 60-277.
It is known from the publication No. 17.

(3) Problems to be Solved by the Invention Incidentally, in such a valve train, since the connection switching mechanism is operated by hydraulic pressure, the fluidity of the hydraulic oil decreases during low temperature periods, causing the operation of the connection switching mechanism to decrease. There may be a delay.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a valve train for an internal combustion engine that can prevent a decrease in fluidity by warming hydraulic oil supplied to a connection switching mechanism. With the goal.

B1 Configuration of the Invention +1) Means for Solving the Problems According to the present invention, a heater is provided in the oil passage between the oil gear rally and the connection switching mechanism.

(2) Effect According to the above configuration, only the hydraulic oil supplied to the coupling switching mechanism is heated by the heater during low temperature periods, reducing energy consumption and reducing the fluidity of the coupling switching mechanism. Actuation delays can be avoided.

(3) Embodiment An embodiment of the present invention will be described below with reference to the drawings. In FIGS. 1, 2, and 3, a pair of intake valves 1a and lb provided in the engine body E are Camshaft 2 rotates from the crankshaft at a reduction ratio of 1/2
A low-speed cam 3.3 and a high-speed cam 5 are provided integrally with the camshaft 2, and a first cam follower is pivotally supported on a rocker shaft 6 parallel to the camshaft 2. 2nd and 30th Tsuka Arm? , 8.9 and the connection switching mechanism IO provided between each rocker arm 7 to 9 to open and close.

The camshaft 2 is rotatably arranged above the engine body E, and the cams 3.3 for both image speeds are connected to each intake valve 1a, lb.
The high-speed cam 5 is integrated into the camshaft 2 in response to
is integrated into the camshaft 2 between the two low-speed cams 3.3. Each of the low-speed cams 3.3 has a shape suitable for low-speed operation of the engine, and each has a high portion 3a that protrudes radially outward within a central angular range. The high-speed cam 5 has a shape suitable for high-speed operation of the engine, and has a high portion 5a having a larger protrusion and center angle range than the high portion 3a.

The rocker shaft 6 is fixedly arranged below the camshaft 2. This rocker shaft 6 has a first cam slipper 7a on its upper part that slides against one of the low-speed cams 3.
The 30th claw arm 9 has a cam slipper 9a on its upper part that slides on the other low-speed cam 3, and the 20th claw arm 8 has a cam slipper 8a on its upper part that slides on the high-speed cam 5. 6 are respectively pivoted adjacent to each other in the axial direction.

The first and 30th hook arms 7.9 have intake valves la, l.
b are interlocked and connected. That is, each intake valve 1a, lb
is biased in the valve-closing direction, that is, upward, by a valve spring 16-17 interposed between a flange 14-15 provided at its upper end and the engine body E, and the first and 20th lever arms Tappet screws 12.13 that abut the upper ends of the intake valves 1a, lb are hinged to the tips of 7.8 so as to be movable forward and backward.

The 20th lever arm 8 is biased by resilient biasing means 18 provided between it and the engine main body E in a direction in which its cam slipper 8a is always in sliding contact with the high-speed cam 5.

The spring biasing means 18 includes a bottomed cylindrical glue lid 19 whose closed end is in contact with the lower surface of the 20th hook arm 8, and the lifter 1.
9 and a lifter spring 20 interposed between the engine body E, and the lifter 19 is slidably fitted into a bottomed hole 21 provided at the side of the engine body.

In FIG. 4, the connection switching mechanism 10 connects the first and second
A first connecting pin 22 that can connect between the 0th and 30th lever arms 7.8, a second connecting pin 23 that can connect between the 2nd and 30th lever arms 8.9, and the first and second connecting pins 22.23.
and a return spring 25 that urges the stopper 24 and each of the connecting pins 22 and 23 toward the disconnection side.

A first guide hole 26 is formed in the tenth hook arm 7 in parallel with the rocker shaft 6, and has a stepped portion 27 in the middle that is open to the twentieth hook arm 8 side and faces the open end side. The first connecting pin 22 is slid into the first guide hole 26, and the closed end of the first guide hole 26 and the first connecting pin 22 are slidably connected to each other.
A hydraulic chamber 28 is defined therebetween. In addition, the stepped portion 27 is configured such that when one end of the first connecting pin 22 comes into contact with the first connecting pin 22, the stepped portion 27
The other end of the guide hole 26 is provided in the middle of the first guide hole 26 such that the other end thereof is located at a position corresponding to between the first and twentieth hook arms 7.8. Further, an oil passage 29 communicating with the hydraulic chamber 28 is bored in the tenth lever arm 7, and a hydraulic pressure supply passage 32 is provided in the rocker shaft 6. The oil passage 29 and the oil pressure supply passage 32 are connected to a communication hole 3 bored in the side wall of the rocker shaft 6.
0, the tenth lever arm 7 is always in communication regardless of the swinging state of the tenth lever arm 7.

A guide hole 33 having the same diameter corresponding to the first guide hole 26 is bored in the 20th lever arm 8 in parallel with the rocker shaft 6 between its both sides, and the guide hole 33 has a length extending over its entire length. The second connecting bin 23 having a diameter of 100 mm is slid together.

The 30th hook arm 9 has the 20th hook? A second guide hole 34 that opens on the −48 side is bored parallel to the rocker shaft 6 in correspondence with the guide hole 33.
4 is set to be the same diameter as the guide hole 33. This second
A disk-shaped stopper 24 is slid into the guide hole 34 , and a small-diameter shaft portion 35 coaxially connected to the stopper 24 is connected to the guide hole 3 bored at the closed end of the second guide hole 34 .
6 is movably inserted. Moreover, a return spring 25 is interposed between the closed end of the second guide hole 34 and the stopper 24 surrounding the shaft portion 35, and this return spring 25 allows
The first two abutted against each other. The second connection pins 22, 23 and the stopper 24 are urged toward the connection release side, that is, toward the hydraulic chamber 28 side.

When high hydraulic pressure is not supplied to the hydraulic chamber 28, the first
．． The second connecting pin 22.23 and the stopper 24 are moved toward the disconnection side by the spring force of the return spring 26, and in this state, the contact surfaces of the first and second connecting pins 22.23 are The abutment surfaces of the second connecting pin 23 and the 7th pawl 24 are located at positions corresponding to between the second and 30th hook arms 8.9, and each rocker arm 7-9 are not connected.

Furthermore, when high hydraulic pressure is supplied to the hydraulic chamber 28, the first. The second connecting pin 22,23 and the stopper 24 move in a direction away from the hydraulic chamber 28 against the spring force of the return spring 26, and the first connecting pin 22 slides into the guide hole 33, and the second connecting pin 22 slides into the second guide hole 34, and each rocker arm 7
~9 are concatenated.

The connection switching mechanism 10 and an oil gear rally 37 for supplying lubricating oil to various parts of the engine are commonly connected to a hydraulic pressure supply source 38. That is, an oil passage 39 communicating with the oil pressure supply passage 32
is connected to a hydraulic pressure supply source 38, and an oil gear rally 37 is branched from this oil path 39. Moreover, in the middle of the oil passage 39 from the connection point of the oil gear rally 37 to the hydraulic pressure supply passage 32, a check valve 40 and an accumulator 4 are arranged in order from the upstream side.
1 and a switching valve 42 are provided.

The check valve 40 allows only the flow of hydraulic oil from the hydraulic pressure supply source 38 toward the connection switching mechanism IO side, and the accumulator 41 is used to suppress fluctuations in the oil pressure supplied to the connection switching mechanism 10. It is configured to adjust the volume of the pressure accumulation chamber 43 by sliding the piston 45 so that the hydraulic pressure of the pressure accumulation chamber 43 communicating with the oil passage 39 and the spring force of the spring 44 are balanced. Ru. Furthermore, the switching valve 42 switches between a state in which the hydraulic pressure from the hydraulic pressure supply tA38 is supplied to the hydraulic pressure supply path 32 and a state in which the hydraulic pressure in the oil path 39 is released to the oil tank 46.

A PTC heater 4 is provided in the pressure storage chamber 43 of the accumulator 41.
7 is installed, and this heater 47 constitutes an electrical closed circuit with a switch 48 and a power source 49.

Next, the operation of this embodiment will be explained. When the engine is operating at low speed, the switching valve 42 transfers the oil pressure in the oil passage 39 to the oil tank 46.
Therefore, in the connection switching mechanism 10, the first. The second connecting pins 22, 23 and the stopper 24 are in the disconnected position as shown in the fourth figure, and the rocker arms 7-9 are not connected.

In this disconnected state, due to the rotational movement of the camshaft 2, the first and 30th lever arms 7°9 swing in response to sliding contact with the low-speed cams 3, 3, and both intake valves 1a, lb are in low-speed The opening and closing operations are performed with timing and lift amount depending on the shape of the cams 3,3.

At this time, the 20th hook arm 8 swings in response to sliding contact with the high-speed cam 5, but the swinging action has no effect on the first and 30th hook arms 57.9.

During high-speed operation of the engine, relatively high-pressure hydraulic oil is supplied from the hydraulic pressure supply source 38 to the hydraulic chamber 28 by switching the switching valve 42 . Therefore, the first connecting pin 22 slides into the guide hole 33, and the second connecting pin 23 slides into the second connecting pin 23.
Each of the rocker arms 7 to 9 is connected by sliding in the guide hole 34. At this time, since the amount of swing of the 20th hook arm 8 slidingly in contact with the high speed cam 5 is the largest, the first and 30th hook arms 7.9 swing together with the 20th hook arm 8,
Both intake valves 1a and lb are opened and closed at timings and riffs +-m according to the shape of the high-speed cam 5.

By the way, by turning on the switch 48 during the low temperature period, the heater 47 is energized and the hydraulic oil flowing through the oil passage 39 is heated. Therefore, the fluidity of the hydraulic oil does not decrease during the switching operation of the connection switching mechanism 10, and prompt operation of the connection switching mechanism 10 is achieved. Moreover, since the heater 47 only needs to heat the hydraulic oil supplied to the connection switching mechanism 10, excluding the oil flowing to the oil gear gallery 37, the heating capacity is relatively small, and the power consumption is correspondingly small. I'm done. In addition, Hi-Yu 47,
Since it is a PTC heater whose power consumption decreases as the temperature rises, power consumption is further reduced.

As another embodiment of the present invention, a heater 47' may be provided in the oil passage 39 on the downstream side of the switching valve 42, as shown by the chain line in FIG.
There is no need to heat the hydraulic oil flowing through the heater 47.
It is possible to further reduce the heat capacity of ', that is, the power consumption.

Further, the rocker shaft 6 may be made of a double structure with a heat insulating material or the like in order to prevent vibrations from moving the heated hydraulic oil up and down.

C1 Effects of the Invention As described above, according to the present invention, since a heater is provided in the oil path between the oil gear rally and the connection switching mechanism, it is possible to minimize energy consumption and prevent deterioration of fluidity of hydraulic oil in low temperature periods. This makes it possible to avoid delays in the operation of the connection switching mechanism.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a longitudinal side view, which is a sectional view taken along line I-1 in FIG. 2, FIG. 2 is a plan view of FIG. 1, and FIG. Sectional view along the mm line in Figure 2, No. 4
The figure is a large-scale sectional view taken along the line IV--IV in FIG. ? , 8.9...rocker arm as a cam follower,
lO...Connection switching mechanism, 37...Oil gear rally,
38... Hydraulic supply source, 39... Oil path, 42... Switching valve, 47... Heater

Claims (3)

[Claims] (1) A connection switching mechanism is provided between a plurality of cam followers to connect and disconnect the cam followers according to the action of hydraulic pressure, and an oil gallery for supplying lubricating oil to each part of the engine and a connection switching mechanism are provided. A valve train for an internal combustion engine in which continuous oil passages are commonly connected to a hydraulic pressure supply source, characterized in that a heater is provided in the oil passage between an oil gallery and a connection switching mechanism. . (2) The valve train for an internal combustion engine according to claim (1), wherein the heater is a PTC heater. (3) A switching valve is interposed in the oil passage between the oil gallery and the connection switching mechanism to switch between a state in which the connection switching mechanism is communicated with a hydraulic pressure supply source and a state in which hydraulic pressure in the oil passage is released. A valve operating system for an internal combustion engine according to claim 1 or 2, wherein the heater is interposed between the switching valve and the connection switching mechanism.