JPH01309A - engine valve gear - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a valve train for an engine, and particularly relates to a valve train for an engine.
The present invention relates to a valve train for an engine in which a cam to be driven is appropriately used depending on the rotational speed of the engine. (Conventional branches/i) Conventionally, as this type of valve train, for example,
There is one that is disclosed in the May 860 publication. This valve train uses a low-speed cam that has a cam profile for 1 speed per cam and a high-speed cam that includes this low-speed cam in an engine that has two intake valves in each cylinder. The cam profile is formed with the right cam for high speed,
The low-speed cam is connected to the low-speed L1 rocker arm that transmits its movement to both intake valves, and the low-speed rocker arm has a ? A high speed rocker arm is provided which is in sliding contact with the general cam and transmits its movement to the low speed port 7-arm, and the low speed rocker arm and the high speed rocker arm are connected to the engine. The means for switching the opening/closing operation characteristics of the valve by setting the valve to an interlocking state or a non-interlocking state according to the rotational speed;

[It's not there. Since this actuating VJ change means is hydraulically operated, there is a hydraulic chamber formed in the 8-speed rocker arm, and this hydraulic chamber 1 IP,
The pressure in the hydraulic chamber is raised to high pressure by freely setting the GJ, and the blank seat protrudes toward the low-speed rocker arm on the side, and the high-speed and low-speed rocker arms are attached to the cam. The fitting hole of the plunger 17- formed in the Ll slider arm for low speed corresponds to the position of the plunger in contact with the base circle of When the pressure in the hydraulic chamber is low, the plunger X/- is pushed back toward the hydraulic chamber by a return spring and becomes a receiver. The above-mentioned high-speed vehicle arm and the rocker shaft 11 foot are connected to the oil pressure T and the oil passage inside the rocker shaft P71.
A lubricant passage is formed in which the lubricating oil flowing through the oil passage at υ is used as hydraulic oil and is supplied to the hydraulic chamber. It is connected to the oil passage in the left. Also, f, 1 supplied into the oil path of the rocker shear V71~
The pressure of the lubricating oil is regulated by the pressure adjusting means according to the engine speed. Then, the operation switching stage L is set to a non-interlocked state and the intake valve is driven by the low-speed cam, while in the high engine speed range f,
1) The supply oil pressure of the lubricating oil is made high and the above-mentioned operating means is switched to the interlocking side. (Problem to be solved by the invention J: 1) By the way, in the above-mentioned conventional moving device, the hydraulic chamber of the actuator 1 holding means is always connected to the oil passage inside the locker shirt 1. Since the hydraulic pressure in the oil passage is in communication with the hydraulic pressure chamber,
When the engine speed changes from a low speed range to a high speed range, or from a high speed range to a low speed range, the oil pressure in the oil passage changes from low pressure to high pressure or high pressure by the hydraulic adjustment means. The pressure is regulated to a low value from
"1i73e5 is activated in the interlocked state. At this time, the 1.
-If the intake valve, which is in contact with the cam base of each cam and the arm, starts lifting when the intake valve is lifted, the plunge of the high-speed rocker arm will start to rise. Since the position and the 1V position of the low-speed rocker arm's IN coupling hole match, and the diameters of the pace leaks are the same, they smoothly transition to the interlocking state or throat interlocking state and no problems occur. If the start of the switching operation starts during the lift of the intake valve when the high-speed rocker arm and the low-speed rocker arm are in contact with a portion other than the cam base circle, there is a problem in that a problem occurs. In other words, the low-speed cam's valve lift curve is included in the high-speed cam's valve lift curve, so if the low-speed rocker arm and the high-speed rocker arm are not interlocked, Therefore, when transitioning from a non-interlocked state to an interlocked state, when the switching operation starts immediately after the high-speed rocker arm starts lifting 1m, the plunger is fully engaged. The engagement between the high-speed rocker arm and the low-speed rocker arm may become incomplete due to U not fitting into the hole, resulting in malfunction of one gate.Then, during the lift, the plunge V -/)-
When pushed back, the low-speed rocker arm separates from the high-speed rocker arm, causing the low-speed cam to make a hitting sound. In addition, if the switching operation starts in the middle of the lift from the interlocked state to the non-interlocked state, the low-speed rocker arm is disengaged from the high-speed rocker arm and the The present invention has been made in view of the above circumstances, and one of its first features is that the cam that drives the valves to be opened and closed is connected to the engine. The purpose of the present invention is to provide an engine valve operating system that can completely prevent malfunction of the engine and the occurrence of the knocking noise caused by it. (Means for resolving the problem η'f) In order to solve the above-mentioned problem, the present invention provides a high-speed camshaft with a ref. A low-speed rotary cam is formed between the cam and a low-speed cam, and this low-speed power 11 is provided with a low-speed rotary cam which is rotatably supported between the valve and the L1 cylinder V frame 1. Install the low-speed Ill [1JJ] on the side of the arm (, adjacent to this), and connect one end to the high-speed cam of the camshaft, so that the IZ!1JJ can be freely attached to the rocker shaft A-foot. A high-speed rocker arm 11 is provided which is pivotally supported, and this high-speed rocker
The low-speed rocker arms on the sides of each arm are equipped with an operation switching means that engages and disengages them according to the engine speed to switch the opening and closing operation of the valve. In the valve device, the cam lift curves of the low-speed cam and the high-speed cam are defined as follows: U (speed force t1) 1 to J until the maximum lift 1-Bl of the low-speed cam after the start;
At least the first half of the predetermined ll1j was made to match or be very close to each other. (Function) According to the present invention according to the above (14th generation), the operation switching means in the high speed range of the engine engages the low speed rocker arm 11 and the high speed Kawaguchi rocker arm to open and close the valve with the high speed cam. In the drive u1 low rotation range, the low-speed cam disengages the low-speed rocker arm and the high-speed rocker arm to reduce the opening/closing drive of the valve by reducing the low-speed cam.At this time, the low-speed cam and the high-speed cam The valve lift curves are very similar to each other and seem to coincide for a predetermined period at the beginning of the valve rift [・I?11], so within that predetermined period, the low speed rocker arm and the high speed rocker arm Even in the case of 10 and 1 when the operation is stopped, the relative movement t does not occur in them, or even if it does, it will be miserable and small.For this reason, during that predetermined period, the above-mentioned operation cutoff Ut'-1', 2
Even if the platform operation starts up, the switching operation will be performed smoothly and reliably, and malfunction will not occur. The low-speed rocker arm does not fall onto the low-speed cam. (Example) Below, 07 suitable examples of the present invention 71! An example will be explained in detail based on the attached drawings. Figures 1 to 4 show an embodiment in which the engine valve train of the present invention is applied to the intake valve side of a three-valve type engine, and Figure 1 shows a side cross-section of the overall configuration. FIG. 2 is a side sectional view of the main part thereof, and FIG. 3 is a plan view of the intake valve side. In the figure, J3 and U are IGI intake valves, and two intake valves 1 are provided per cylinder. Further, 2 is an exhaust valve, and one IJI air valve 2 is provided for each cylinder. 3 is a camshaft, and this camshaft 3 has three cams 4a-4b and 5 for driving intake valves and one cam 6 for driving exhaust valves per cylinder.
and C are provided. Three intake valve drive cams/la, 4b, and 5, the other two are low-speed cams 4 that control the low-speed cam profile.
a・ibC゛, the remaining one is the high speed cam 5, which has a cam profile for high speeds that has a larger riff 1 to darkness than the low speed cam, and the low speed cams 4a and 4b have a A high-speed cam 5 and a cam 6 for driving the exhaust pulse 1 are arranged between the two ends. Rocker shafts 7 and 8 are provided above the camshaft 3 on both sides of the camshaft 3, and on the rocker shaft 7 on the 1j1 air valve 2 side, a cam 6 for driving the JJI air valve of the cam I 3 is installed. A rocker arm 24 for driving the exhaust pulse 1 is movably provided between the exhaust valve 2 and the valve stem 2a of the exhaust valve 2. Also, add 1″ to the 1st horn j-shi+-nod 8 on the intake pulse 11 side!
Rocker arms 9, 10, and 11 for three intake valves ψ and 11 are movably arranged. The two rocker arms installed on both sides are low-speed rocker arms 9 and 10; The low-speed cams 4a and 4b are in contact with each other, and the other moving end 7-no1 parts 9b and 10b are connected to the valve stems 1a and 1a of the intake valve 1 via a hydraulic lash V star 13. A hook is provided extending substantially linearly between the low-speed cams 4a and 4b and the intake valve 1 from the side beams. In addition, each of the low speed rocker arms 9 and 10 are formed symmetrically. The rocker arm provided between i''L and the like is a high-speed rocker arm 11, and this high-speed Kawaguchi rocker arm 11 has an arm portion 11a at the moving end on one side of the camshaft 3 as a slipper. Cam by 14!+
It is slidingly in contact with the high speed cam 5 of 1113. In addition, as shown in FIG.
1 and 1 according to the engine rotation speed to switch the opening/closing operation characteristics of the intake pulses 11 and 1.
I change means 15 is provided. This operation switching means 15 is a high-speed rocker art t111.
Hydraulic pressure integrally formed in the arm portion 11b on the valve side of the
All, 16, and 1QGJ slidably in this hydraulic chamber 1G.
When the pressure inside the hydraulic chamber 16 becomes high, the plunger 17 projects laterally toward the low-speed rocker arms 9 and 10, and the high-speed rocker arms 11 and low-speed rocker arms 9 and 10 are activated. Both cams 4a and 4
(corresponding to the position of the plunger 17 when it is in contact with the base slide of b. The fitting hole 18 of the plunge 1 no. 17 and the fitting hole 18 of the plunge 1 no.
- A receiver 20 that pushes the plunger 17 back toward the hydraulic chamber 1G side by a return spring 19. As shown in FIG. 2, the hydraulic chamber 1G is communicated with an oil passage 8a in the rocker seat 8 through an oil supply passage 21 formed in the rocker arm 11 for high speed. The lubricating oil that is force-fed into the oil passage 8a through the oil supply passage 21 into the hydraulic chamber 16 is supplied as hydraulic oil. In addition, the oil passage 8a in the locker ship p71-8 is connected to the oil passage 111d''1 in the A-il pan 26 as shown in the fifth [1].
The oil is pumped and supplied by the oil pump 27, and this oil passage (3) of the V-lift 8
A solenoid valve 28 is provided in the return passage from I to the delta oil pan 26 to adjust the pressure within the blood path 8a. Note that the oil pump 27 is rotatably driven by the engine crankshaft, and
For this reason, the discharge pressure of the tenon rises to high pressure when the engine is running at high speeds of 0"l, and at low speeds, the discharge pressure decreases and becomes low pressure, but the pressure inside the oil passage 8a is reduced by the solenoid valve 2ε3. By controlling the opening of 1
At low speed n5, where the engine rotation speed is below the set rotation speed, the engine leans steadily, and when the engine rotation speed is higher than the set rotation speed, at 9 speed, the ζ:I pressure is set at 11. It is designed so that you can lean on it. By the way, the aforementioned low-speed cam 48φ4b and high-speed cam 5 have their own cam riffs]・Song I! i! As shown in FIG. 4, the (valve opening/closing operation characteristics) are set to match or be very similar for at least a predetermined period T in the first half of the period from the start of the volume valve to the maximum lift. In Fig. 4, (a) shows the Jj lift curve of the high-speed cam 5, and (b) shows the cam lift curve 1- of the low-speed cam 4a and 4b.
The cam lift curves (a) and (b) have slightly different valve opening timings, but the low speed cams 4a and 4b start lifting immediately after the low speed cams 4a and 4b start lifting. Until just before maximum lift - C correction 1
- be consistent over a long period of time. The reason why the +1 period is 5 degrees is that in order to avoid improving the intake air filling efficiency at high engine speeds, the A- I took a long burlap period (there is a C because it is good, but
Within the practical rotational speed range of one engine, the difference in valve lift l-1 makes a difference by 1j more than the difference in valve lift I and timing, so in this embodiment, more emphasis is placed on valve lift. Therefore, in the engine valve train constructed in this way, 1
In the n speed rotation range of the engine, the pressure of the lubricant 81 oil that is pumped into the oil passage 8a of the rocker shaft 11 shaft 8 is made high pressure, and this lubricating oil 1 [8 oil 1] passes through the oil supply passage 21 as hydraulic oil to the high-speed locker. The oil 13-'416 of the arm 11 is supplied. Then, the blanks 17 fit into the fitting holes 18 of the low-speed rocker arms 9 and 10, and the high-speed rocker)
The gnome 11 engages with the low-speed rocker arms 9 and 10, and they become a single unit, resulting in 3! I! The dynamic state becomes fp4, and the intake valve 1 is driven to open and close by the high-speed cam 5. - #j, when the engine is running at low speed, the rocker shield 1771
The pressure of the lubricating oil force-fed to the oil passage 8a in -8 is reduced to a low pressure, and therefore the pressure in the hydraulic chamber 16 is also reduced. The plunge tz -17 is the return spring 19 of the receiver 20, and the hydraulic pressure 'i! pushed back into 16,
As a result, the high-speed rocker arm 11 is disengaged from the low-speed rocker arms 9 and 10, so that they are in a non-interlocked state, and the two intake valves 1 are driven to open and close by the low-speed cams 4a and 4b. At this time, for low speed []]
The gear arms 9 and 10 and the high-speed rocker arm 11 are in sliding contact with the low-speed cams 4a and 4b and the high-speed cam 5, respectively. However, in this embodiment, the cam lift curves of the high-speed cam 5 and the low-speed cams 4a and 4b are matched from valve rif 1 to the start side, so the valve lift curves are matched ( During this period, the low-speed rocker arms 9 and 10 and the high-speed rocker arm 11 move in exactly the same way, and no relative movement occurs between them. A relative movement will occur between the low-speed rocker arms 9 and 10 and the high-speed rocker arm 11. On the other hand, the pressure of the lubricating oil supplied to the oil passage 8a in the rockership p]].8, that is, the pressure chamber 1G The pressure inside the cam @3
Regardless of the rotational position of the low-speed rocker arms 9 and 10 and the high-speed rocker arms 1''1, regardless of whether the low-speed rocker arms 9 and 10 and the high-speed rocker arms 1''1 are lifted or not, the low-speed rotation will depend on the engine speed. In the low speed range, the pressure is regulated to a low pressure that disables the actuating 8th stage 15, and to a high pressure that makes the tenon actuator 1 moss means 15 interlocked in the high rotation range, so the low speed rocker arms 9 and 10 and high speed rocker arm 1
During the lift with 1, the cutting 11 operation of the operating cutting stage 15 may start. However, as mentioned above, the valve lift curves of the low-speed cams 4a and 4b and the high-speed cam 5 on the lift start side are matched for a predetermined period of time, so while the valve lift curves are matched, Even if the switching operation of the operation switching means 15 is activated, the low-speed Kawaguchi Tsuka arm 9, 10, 8
There is no relative movement in the continuous rocker arm 11, so plunge 1? Since the axes of -17 and the fitting hole 18 are aligned, switching from the non-interlocking state to the interlocking state and switching from the interlocking state to the J-to-interlocking state are both performed smoothly and reliably. For this reason, immediately after the start of the lift of the intake valve 1, there is a malfunction between the speed rocker arms 11 and the speed rocker arms 9 and 10, both in the interlocked state and in the non-interlocked state. In addition, even if a non-coupled state occurs immediately after the start of the lift, the low-speed lever arm 910 will not move over the low-speed cams 4a and 4b. This will prevent the ball from falling, and the occurrence of blows due to this can be prevented as much as 1 + J.
In addition, deterioration in the durability of the operating cutter stage 15W can be prevented as much as possible. The graph in Figure 6 shows the hydraulic pressure supplied in the hydraulic chamber 1G of the ON actuator when switching from the interlocking state to the interlocking state.
), and the graphs in Figure 7 show the characteristics of the supplied hydraulic pressure in the OFrFr operating hydraulic chamber 1G when switching from the linked state to the non-a-controlled state, but as shown by the solid line in these graphs, , when switching to interlocking state, solenoid valve 2
8, the hydraulic pressure inside the rocker shaft 8 and the hydraulic chamber 1G is quickly reduced to the set pressure on the high pressure side by the so-called water hammer effect.
On the other hand, when switching to the No. 1 linked state, the pressure in the hydraulic chamber 16 can be quickly increased to the low pressure side by instantly widening the opening of the solenoid valve 28. The pressure can be raised to a low pressure below the set pressure value P1. Accordingly, the moving speed of plunge t・-17 is r,! (It is possible to prevent switching operation failure by 1 = Vc': 5.) In addition, in this way, high pressures higher than the set pressure value 22 and set pressure 1a can be prevented.
If the paper pressure becomes less than P 1 for a short period of time, there is no possibility that the lubricity of the valve O1 end portion will be affected.・[Effects] To summarize, according to the present invention, the cam lift curves of the low-speed cam and the high-speed cam are determined from the start of the lift of the low-speed cam until the maximum lift of the low-speed cam. Since the coincidence bt, , < is made extremely close at least for the predetermined period of the previous <r, it is possible that relative movement will occur between the high-speed rocker arm and the low-speed rocker arm during the predetermined period 191 above. There is no relative movement, and if any relative movement occurs, it will be extremely small. Therefore, even if the rim operation of the high-speed rocker arm and the low-speed rocker arm starts to operate in conjunction or in a non-coupled manner immediately after the valve starts opening, the cutting process can be performed smoothly and reliably. U: Malfunction of the f-stage can be prevented as much as possible. Also, if the high-speed rocker arm and the low-speed rocker arm become uncoupled immediately after the valve starts opening, the low-speed rocker arm will fall onto the low-speed cam. This not only prevents the occurrence of stroke Δ due to this, but also increases the durability of the valve train and improves its reliability.

[Brief explanation of the drawing]

Figures 1 to 3 show an embodiment in which the engine valve train of the present invention is applied to the intake valve side of a three-valve type engine, and Figure 1 t shows the overall configuration of the present invention.
IrIfT surface view, Figure 2 is the main part opening view in Figure 1,
Fig. 3 is a plan view of the intake valve side, Fig. 4 is an example of the valve riff 1 to curve of each of the low-speed cam and high-speed cam adopted in the present invention, and Fig. 5 is a plan view of the intake valve side. A diagram showing an example of a lubricating oil pumping device, Figure 6 is a graph showing an example of the f+ characteristic of the oil pressure supplied to the hydraulic chamber when switching to the IP operating state, and Figure 7 is a diagram showing an example of the f+ characteristic of the oil pressure supplied to the hydraulic chamber when switching to the IP operating state. It is a graph figure which shows an example of 1X f'l of the oil pressure supplied to the hydraulic pressure chamber at the time. 1...(Intake) valve 3...Camshaft 4a, 4b...Low speed cam 5...High speed cam 8...Rocker shifter 9・10...Low speed rocker arm 11...High speed rocker arm 15...
・Operation cut-off H-f-stage patent applicant Mazda Co., Ltd. agent
Person Patent Attorney - Color I Same Patent Attorney Matsumoto Kamagari Figure 1 Figure 2 Figure 3 ja Figure 4 1 S1

Claims (1)

[Claims] A high-speed cam and a low-speed cam with different lift amounts are formed on the camshaft, and the low-speed cam is provided with a low-speed rocker arm that spans between the valve and is swingably supported on the rocker shaft. A high-speed rocker arm is provided adjacent to the low-speed rocker arm on the side thereof, and is pivotably supported on the rocker shaft with one end in contact with the high-speed cam of the camshaft. In an engine valve train, a high-speed rocker arm and a low-speed rocker arm on the side thereof are provided with operation switching means for engaging and disengaging them according to the engine speed to switch the opening/closing operation characteristics of the valve. , the cam lift curves of the low-speed cam and the high-speed cam are made to match or be very similar for at least a predetermined period in the first half from the start of lift of the low-speed cam to the maximum lift of the low-speed cam. An engine valve train characterized by: