JPS6026109A - Intake/exhaust valve driving device of internal- combustion engine - Google Patents

Abstract

PURPOSE:To prevent a cam from being forcibly swiveled by means of a valve spring by forming the cam so as to have flat cam faces on the captioned device adjusting, by means of the cam, an angle of a lever which is in contact with the back side of a rocker arm and changes a position of a fulcrum. CONSTITUTION:A valve 12 is opened and closed by means of a cam 11 through a rocker arm 16, while a position A of a fulcrum of said arm 16 is changed by a slant angle of a lever 17 with its one end supported by means of an oil pressure pivot 19 and the other end adjusted by means of a control cam 20. Said cam 20 is swiveled according to an engine operational condition by means of an oil pressure actuator and changes the lifting quantity of the valve 12. Formation of the control cam 20 into the shape of having the plural number of flat cam faces 20a, 20b, 20c, 20d, 20e prevents it from being forcibly swiveled due to reaction force received from a valve spring during lifting of the valve 12.

Description

[Detailed Description of the Invention] This invention relates to the opening/closing timing of intake and exhaust valves and valve rifts.
The present invention relates to an intake/exhaust valve drive device for an internal combustion engine that performs variable control according to operating conditions.

Various intake and exhaust valve drive devices have been proposed in the past, which variably control the opening/closing timing and valve lift of the intake and exhaust valves according to engine operating conditions so as to always optimize valve alignment and fresh air filling efficiency. However, one of the
US Pat. No. 3,413,965 shown in (9) is known.

This ffff1 movement device has one end in contact with the valve drive cam/, and the other end fitted and supported by the stem end of the intake and exhaust valve. By swinging the left and right sides of the rocker arm 3 while contacting the fulcrum with the cam 3, the lift of the cam 3 is caused by the lift of the intake and exhaust valve 3.
In particular, the lever 5 is rotatably supported at one end thereof, and its inclination is regulated by a control cam. The control cam t is rotationally driven in an appropriate phase according to engine operating conditions by a drive mechanism such as a hydraulic actuator, thereby variably controlling the opening/closing timing and lift amount of the intake/exhaust valve 2. That is, for example, if the amount by which the lever 3 is depressed by the control cam B is large, the free end of the lever δ and the rocker arm 3 will be close to each other in the base circle state of the valve drive cam, and therefore the opening of the intake and exhaust valves will be As the valve timing advances, the valve lift amount increases, and if the -pressing down lit by the small control cam 2 is small, the base circle state of the same L valve driving cam / is attemo L / bar, 5 (7) free end. Since the rocker arm 3 is spaced apart from the rocker arm 3, the opening timing of the intake and exhaust valves is delayed and the amount of frit is reduced.

However, in such a conventional intake/exhaust valve drive device, the control cam t'? :The control shaft 6α is rotated by a hydraulic actuator to control the lift. The periodically fluctuating load applied to the cam B acts on the hydraulic actuator to cause the oil in the hydraulic actuator to leak, forcing the control cam l to rotate. For this reason, there was a problem in that stable valve lift characteristics due to the valve drive cam could not be obtained, and output performance, high-speed drivability, etc. were impaired.

The present invention was made in view of the above-mentioned conventional problems, and includes forming at least two flat cam surfaces on the control cam so that the control cam rotates according to the operating state of the engine. The purpose of this is to prevent the lever from forcibly rotating the control cam.

For this reason, this invention has a valve drive cam that rotates in synchronization with engine rotation, and one end of which is in contact with this valve drive cam.
a rocker arm whose other end is connected to the valve stem; a lever which is disposed approximately along the back surface of the rocker arm and whose back surface is in fulcrum contact; a bracket supporting one end, a control cam having at least two flat cam surfaces, the valve of the bracket, and a control cam supporting the other end of the lever on the normally-acting cam side; Support gI
It is made up of 414 components, including a shaft I and an actuator that rotates this support shaft one rotation according to the operating conditions of the engine.

Below, the drawings for implementing the present invention will be described in detail.

FIG. 2 is a front view of one embodiment. In the same figure,
// is a valve drive cam synchronized with the engine rotation, /s is an intake and exhaust valve, 7.3 is a blade spring, /η is a cylinder head /j [fixed bracket, /l is a valve, actual operation] The lift of the cam is transferred to the intake and exhaust valves/2 by the erotic arm, 7
7G is a lever that supports the rocker arm/O's back lla as a fulcrum and also holds the rocker shaft/7.

Lever/7 is a bar stem (110 end is a hydraulic pivot)
/ P (Fulcrum support piece slips from C, valve drive cam 11
The 1Il end is abutted and supported by the control cam 20.

This hydraulic pivot has a bottomed outer cylinder part /9a and an inner pouch part /9
b, and a high pressure chamber /9c is formed between them. Inside the high pressure chamber 79c, there is a coil spring/reel d1.
Check valve/ri e1 check valve/'9. '! ;/Supporting spring/f1 check valve/9. and 7 blink/9
A housing/9Q is provided to support f. There is an oil reservoir in the inner cylinder part/9b/'? h is formed, communicating hole /9
Connects to hyperbaric chamber/9c' at i. The oil reservoir /n is connected to a communication hole /ηα, which will be described later, via a communication hole /9j.

The above control cam 20 has six substantially flat cam surfaces θa, 20b, 20c, 20d, :lOa in the figure.
, 2Of f, and the lift amount can be changed in stages.

Control Pnom-0 has support 111.2 i plus key: t/
It is fixed from the VC, and the hollow part of the support shaft is a force-lubricated blade/θ path 21b. This passage, 7/b
1 and 22 are connected to the external σ)-A/' supply source, and are connected to the oil reservoir 79h of the hydraulic pressure hole 74τ punt/9 through the communication hole /ηα. With other brackets for saving in ./ll,
Bottom, 7' racket/μC from 23Vc (fixed
ing.

Figure 3 shows the hydraulic actuator control system 4. ￥i:/i Chi, upper QQ support a:), / σ
) 4 Vcf; l-1fLtl U day A12, (-σ) vane job is fixed in housing 3/α. -Also, the supporting axis/σ-no other M? M [f mali'al It-angle-cessor 3.2 is installed. σ) The rotation angle sensor 3 unit is attached to the insulator 3:2e'a:: butt seat C1 to the no. The flange 32c1 fixed to the end of the spindle/this brush 32c'l
It consists of screws 3.2d etc. that are fixed to the support 4iIi]/. The f78i+ valve system shown in FIG. 2 is arranged between the hydraulic actuator 3/ and the rotation angle sensor 3.2.

, 31 is an electrohydraulic switching valve, the A and :B boats of this are hydraulic actuators, and the two suction/discharge ports 3/c.

Connects to J/d, P boat connects to oil pump, Rin boat connects to oil pan, ? It leads to t. , 37 is a check valve installed in the middle of the oil supply pipe, 3 is an accumulator connected between the check valve 37 and the P boat, and A9. lO is a relief valve. In addition, 〃/ is the output of the three rotation angle sensors (Q, engine throttle opening speed per revolution, water temperature,
This is a control circuit that sends a control current to the electromagnetic hydraulic switching valve 31J- according to output signals such as intake air amount and intake negative pressure.

Next, the effect will be explained.

Now, in Fig. 2, the C1 control cam 0 is the cam with the largest lift, 20a, and the valve drive cam of lever/7 is the cam 20a.
In the state where the lever /7 is in contact with the side smoke, the lever /7 is pushed down toward the valve drive cam // side. For this reason,
Rocker arm/back side of l/lever with fulcrum contact at 2σ/
The lower surface of 7/7cL (, lowers, and these fulcrum contact points A move toward the valve drive cam side, so the valve drive cam//
As the rocker arm 2 swings due to the lift, it is transmitted to the intake and exhaust valves, resulting in a valve lift characteristic of 4ffe as shown by curve X in Figure 4, the valve lift is large, and the valve lift rises quickly. The fall is delayed.

On the other hand, fit! I (m) When the cam 0 rotates and comes into contact with the lever /7 with the cam face OB with a small lift, the valve drive cam // side end of the lever /7 rises and the lower surface of the lever /7 comes into contact with the lever /7. 7α also retreats upward.

For this reason, the fulcrum contact point moves to the side opposite to the pulp drive cam // side, and as shown by curve Y in Figure 4, the amount of bar A/buri 7 is small, the rise of the lift is slow, and the fall of the lift is slow. becomes faster.

In this way, the valve lift can be changed in stages by turning the control force 0.

Here, the control cam 2o is rotated by a hydraulic actuator 3/. That is, the above control circuit q
/ emits an output current set based on the output of the rotation angle sensor 32 and other signals corresponding to the engine operating state.

This current operates the electrohydraulic switching valve 3 μm, and
Connect any of the B boats to the gP boat, and connect the hydraulic pressure discharged from the oil pump 3.5 straddle accumulator, J'g to the hydraulic actuator, ? / vane 31
b'a? Rotation side a1 in either direction. Therefore, the pivot, I! / rotates in the same way to control the lift with zero control force. As a result of this operation, the target valve lift I/mVc is achieved via the lever 77, and the brush 3.2
By contacting one of the terminals 32b and 32b, the output of the rotation angle sensor 32 is input to the control circuit l/, and the electrohydraulic switching valve, ? Feed dock control is performed to maintain η in a neutral state.

Therefore, after controlling the target lift, the hydraulic actuator, ? The oil supply to / is stopped and the control cam,
Even if the lever/7 stably contacts the cam direction 20b of the valve 20 and the valve lift amount becomes large, the valve lift amount can be maintained in a constant state.

Note that the switching valve 31 is of the ABT connection type, and in the neutral state, the P boat is closed and the discharge pressure of the oil pump 35 is controlled by the check valve or ? J to accumulator 3g via 7
The pressure accumulated in the accumulator 3g is regulated by the relief valve 3. Then, the accumulated hydraulic pressure of 2" can be used as hydraulic oil for the hydraulic actuator 3/ in the next control 1 @ operation, so the discharge amount of the oil pump 3S is small and small, making the oil pump 3J more compact. is also possible.

1. The responsiveness of hydraulic actuator 3/ when starting the engine should also be improved.

FIGS. 5(α) and (6) show other embodiments. A small hole Og is formed in the control cam 20, and oil is introduced between the control cam 20 and the coil support shaft 2/, so that lubrication can be achieved. This allows multi-cylinder engines with four or more cylinders to use ill! The driving force of the cam 20 can be reduced. This is because in a multi-cylinder engine, at least one cylinder's intake and exhaust valves are replaced by IJ valves, and the valve springs are damaged. Since the reaction force is acting on the control cam, the 200 rotation of the control cam is unstable, but due to the elastic force exerted by the coil spring 1oVcF8 due to the operation of the hydraulic actuator 3, the valve lift is stopped. When entering the f17I
This is because it can be rotated by 77 degrees. Note that one end of the lever/7 on the lever stem side is attached to a bracket/l instead of the hydraulic pin.
/ Can be used with the Asyastopo sword/tora screwed together,
By adjusting the threading of this adjustment bolt, the valve clearance can be adjusted.

6 and 7 show a front view and a plan view 7 of yet another embodiment of the invention. , 3/ turns to the spindle 2/! @] The first gear is inserted into the eye, and each end of three coil springs is locked to the first gear, 3/, and the same control j cam: lO. j,? .

This is a snap ring that restricts the axial movement of the sat control boom 7, 20 and the first gear 5/. 5.5 is the first
A second gear that meshes with gear 5/, this second gear, 5.5
is fixed to the support shaft 5z. This support shaft 5t is rotatably supported by a racket/l, a racket 22, etc. The end of the support shaft 3z is connected to the rotating shaft of a stepping motor 6r as an actuator for the camshaft O through a connector 5qyt.
The drive is controlled by a pulse current output from.

According to this, when the stepping motor 6 is operated and the second gear 63 is rotated counterclockwise in FIG. 6, the first gear j/ is rotated in the direction 6F. A clockwise rotational force is applied to the coil springs 3' and 2, causing the control ω]1 camco ON0♀+j to rotate in the 1 direction VC. If the intake and exhaust valves / and 2 are lifted, the reaction force of the valve spring /3 acts on the control cam 20 with the force /<-/7, so ib! I won't tell you 2061 times 4 times. However, when the valve lift stops and the Ronca arm/2 comes to the base circle of the Kutsudobu drive cam, the reaction force of the valve spring/3 becomes extremely small, and the control surface cam: l.

rotates in one direction.

As a result, the stepping motor JJ has the second gears J, 5,
Through the first gear j II f, there is a coil spring, enough to store 5 K Ill'ill power/1. Compared to the case where the control blade is directly driven, it requires a much smaller driving force and is economical. Also in this embodiment 1, the control force of the bar 77 is low.

% 27 Stably supported by Iflo, even if the reaction force of the valve spring/3 becomes high, the valve lift +
jjj1 work can be executed in a stable state.

Figure 8 shows some examples of wavy parts on the surface of one piece of cams 0. The wavy part that forms h7 and comes into contact with it. i? Kara”j
Y , support @ , 2 / Fixedly installed? show. In this case, the three coil springs are mounted on the support shaft so that the cam 20 can slide and rotate in the axial direction. In addition, each wavy city Oh,
:1 When O-i is engaged, control + flυ bim, 2
Each cam of C-;lOa, ,! Ob, Ko (:lC
, 'IOd, :lOs, :lOf are in a position where the lever/7Vc stably contacts. 1 It takes (g formation VC'1-resistance force stored during valve lift ft 7C coil spring, 5-resilient force, /<
/l・Even if a person suddenly opens the frit while it is in a resting state, due to the frictional engagement of the wavy portion, 20h, :)Oi, the ftllJ value L and O will reach the target surface by its elastic force. It is possible to prevent over-stitching. -4
- In other words, place at least 2 or more substantially flat cams on the upper side of the city 1r, 0) VC7J11, color 2
In the same way as 0j, the control cam 2 can be moved more stably and stepwise by frictionally engaging the wavy surfaces oh and oi.
0 rotation control can be performed.

Figure 9 shows the main drive wheel 2/ and the support shaft 2/ fixed to the support shaft.
II, 01c, Benototo Z8 with 2 driven vehicles fixed to
Figure 10 shows a cog belt GL suspended between the cog wheels I-, 4, II fixed to the spindle 5J and the cog wheel 66 fixed to the spindle co/. , and Fig. 11 shows the flange O' fixed to the support shaft 5z.
Main drive vehicle t7 with Ia and driven vehicle 6♂ fixed to support shaft 2/
A flat belt is suspended between the two. Even in these three embodiments, it is possible to obtain the same functions and effects as those described for the embodiments shown in FIGS. 7 and 8.

As explained above, according to this invention, the control cam [
Flat cam curve 4't that stably contacts the lever without applying C rotational force! j 7) Since the support 1111 of the city IT wholesale cam is a hydraulic actuator and the kiln is configured to be rotated by the actuator with the motor 4, it receives the reaction force of the vanotobusbring during valve lift. This prevents the control cam from rotating under force, and the lift characteristics of the valve and drive cam are accurately transmitted to the intake and exhaust valves. :ri': 0; Preventing the increase of 5y in higher harmoex, high-speed performance? A λ effect such as being able to maintain a stable Fl can be obtained. .

Simple diagram of iQ i9J 1st F\i is a cross-sectional view of the conventional intake/exhaust diopter device;
Figure 2 is a sectional view showing an embodiment of the intake/HP air valve and drive device according to the present invention, Figure 31 is a hydraulic control system diagram of a hydraulic actuator, and Figure 4 & , Fig. 5 Crt) is the improved Kaname i56 No. 11 "
Figure 1n1 and Figure 5 (6) are the same plan views, Figure 6 is the e; The plan view, FIG. 9, FIG. 10, and semi-H diagram are plan views of other partially improved main parts.

//...valve drive cam, /no...intake and exhaust valve, 7.3
...Valve spring, /q...Bracket, /F...Rocker arm, /7...Lever, /R...Hydraulic pivot, 20...Hou J + Wholesale cam, 2/...Support axis, 3/.../li If, γri-y-yuta, r
7 Kuchiyu x -p), ll'...t! ;IJ
m++ lLJ road 5.5g...; (Chipping mode 6
, (actuator) 1° Fig. 1 Fig. 2 Fig. 4 Fig. 5 (a) (b) Fig. 6 Fig. 7 Fig. 8 Fig. 48- Fig. 9 Fig. 10 Fig. 11

Claims (1)

[Claims] a valve drive cam that rotates in synchronization with the rotation of the engine; a rocker arm that -i is in pressure contact with the valve drive cam and whose other end is linked to the valve stem; The bracket that supports the rocker arm on the valve stem side of the lever has at least two substantially flat cam surfaces, and the In the drive cam mK, a control cam that supports the other end of the lever, a support shaft that supports this control cam, and this support shaft are rotated according to engine operating conditions. 1. An intake and exhaust valve drive device for an internal combustion engine, comprising an actuator.