JPH04107415U - Internal combustion engine valve timing control device - Google Patents

Abstract

(57) [Summary] [Purpose] The relative rotational position between the camshaft and sprocket is controlled in three stages, and the intermediate relative rotational position is reliably regulated to stabilize valve timing according to engine operating conditions. and can be controlled with high precision. [Structure] In a device that converts the relative rotation between a camshaft 1 and a sprocket 3 using a phase conversion means 4, a cylinder hole is provided in which a piston 24 is slidably housed in the outer circumference of a holding member 5 connected to the camshaft 1. 23, and a regulating hole 25 is provided in the inner peripheral part of the sprocket body 8, into which the tip of the piston 24 enters from the cylinder hole 23,
The piston 24 is configured to be moved forward or backward within the regulating hole 25 by an actuating mechanism 26 depending on the operating state of the engine.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention variable controls the opening and closing timing of the intake and exhaust valves of an internal combustion engine according to the operating conditions. This invention relates to a valve timing control device that controls valve timing.

0002

[Conventional technology]

Various conventional valve timing control devices of this type have been provided. As an example, the one described in U.S. Patent No. 4,535,731 is known. There is.

0003 To give you an overview, the camshaft that controls the opening and closing of the intake and exhaust valves is located at the front end. External teeth are formed on the outer periphery of the On the other hand, the camshaft is supported on the outside of the front end. The outer cylinder has a sprocket on its outer periphery that transmits the rotational force of the engine via the timing chain. It is equipped with a rocket and internal teeth are formed on the inner periphery. And of this At least one of the teeth on the inner and outer peripheries is located between the teeth and the outer teeth of the camshaft. A cylindrical gear formed with helical teeth meshes with the other side, and this cylindrical gear is Depending on the situation, the axial direction of the camshaft is adjusted by the hydraulic pressure of the hydraulic circuit and the spring force of the compression spring. By moving the camshaft in the direction, the camshaft can be rotated relative to the sprocket. This controls the opening and closing timing of the intake and exhaust valves.

0004

[Problem that the idea aims to solve]

However, in the conventional valve timing control device, the hydraulic pressure in the pressure chamber , a high oil Pressure control and conversely moving the cylindrical gear in the other direction using the spring force of the compression spring. There is only a two-step ON-OFF switching control with low oil pressure control for the purpose of operation. death Therefore, the relative rotational position between the camshaft and sprocket is also the maximum forward and reverse rotational position. Since there are only two locations, valve timing can be controlled accurately according to engine operating conditions. Can not.

[0005] Therefore, the hydraulic pressure in the pressure chamber is controlled to stop the cylindrical gear at an arbitrary intermediate position. , It is also considered that the valve timing can be controlled in three stages by this, The characteristics of lubricating oil (control oil), such as viscosity, change depending on changes in temperature and engine speed. Therefore, it is extremely difficult to keep the oil pressure constant. others Therefore, it becomes difficult to reliably control the movement position of the cylindrical gear in the intermediate position, and the valve tie This may lead to instability of timing control.

[0006]

[Means to solve the problem]

This invention was devised in view of the above-mentioned conventional situation, and the driving force is transmitted from the engine. a rotating body that rotates, and a camshaft that opens and closes a valve by the rotational force from the rotating body. is relatively rotated by the phase conversion means according to the engine operating state to open and close the valve. In a valve timing control device that controls timing, the camshaft has an internal A cylinder hole is provided in which the locking piston is slidably housed, while the The tip of the piston extends into a position facing the cylinder hole on the inner circumference of the body. A regulating hole is provided to allow the piston to move backward, and the piston is further regulated from the cylinder hole. It is characterized by the provision of an operating mechanism that moves the engine forward and backward in accordance with the operating state of the engine. are doing.

[0007]

[Effect]

When the engine operating condition is in a low load range, the camshaft is turned into a rotating body by the phase conversion means. For example, when the camshaft is rotated to the maximum in one direction, the camshaft is It is held in a rotational position that delays the timing. On the other hand, when moving to a high load range, phase conversion The maximum relative rotation of the camshaft in the other direction is performed by a means to adjust the closing timing of the intake valve. is held in a rotating position that accelerates the rotation. In this case, the locking piston is It is completely housed within the cylinder hole and does not extend into the regulating hole.

[0008] When the engine operating state shifts to a medium load range, for example, the piston A force is applied in the advancing direction by the operating mechanism. Therefore, the phase conversion means As mentioned above, the camshaft rotates relative to the rotating body in a predetermined direction, and the cylinder When the hole and the regulation hole match, the tip of the piston advances into the regulation hole. to intervene. This locks the relative rotation between the camshaft and the rotating body. The camshaft is stably and reliably held at a substantially intermediate relative rotational position.

[0009] In addition, if the engine operating state shifts to a lower load range or a higher load range, The piston quickly moves back from the regulation hole into the cylinder hole by the actuating mechanism, and the camshaft Allows relative rotation between the shaft and rotating body.

0010

【Example】

Figure 1 shows the valve timing control device of the present invention applied to the intake valve of a DOHC internal combustion engine. An example of application to the side is shown.

[0011] 1 in the figure is supported by a cam bearing 2a on the upper part of the cylinder head 2, and a A camshaft having a cam that opens and closes the intake valve; 3 is the camshaft 1; It is located on the one end 1a side and is driven from a crankshaft (not shown) via a timing chain. Sprocket is a rotating body through which power is transmitted, 4 is camshaft 1 and sprocket The camshaft 1 is a phase conversion means for converting forward and reverse relative rotation with respect to the camshaft 1. A cylindrical holding member 5 is screwed from the axial direction to a flange portion 1b at one end portion 1a. It is tightened and fixed with a bolt 6. This holding member 5 is attached to the camshaft 1 It has an annular portion 5a on one end of the side to which the flange portion 1b fits, and has an outer ring portion 5a. Helical tooth-shaped external teeth 5b are formed on the peripheral surface.

0012 The sprocket 3 is a cylindrical sprocket whose front end 8a is closed with a disc-shaped cover 7. The sprocket body 8 is provided at the outer end of the sprocket body 8 on the camshaft 1 side. and a toothed portion 9 around which the timing chain is wound. The sp The rocket body 8 has an inner circumferential surface of a rear end portion 8b on the side of the tooth portions 9 on the outer circumferential surface of the annular portion 5a. It is slidably supported, and internal teeth 8c are provided on the inner circumferential surface on the front end 8a side. There is.

[0013] The phase changing means 4 is interposed between the sprocket body 8 and the holding member 5. A cylindrical gear 10 and a gear drive machine that moves the cylindrical gear 10 in the axial direction of a camshaft. It is equipped with a structure 11. The cylindrical gear 10 is a long gear cut from a direction perpendicular to the axis. Consisting of front and rear gear components 10a and 10b that are formed separately, both gear components 10a and 10b are drawn to each other via a connecting pin 12 and a spring 13. The inner teeth 8c and the outer teeth 5b are elastically connected to each other on the inner and outer peripheries. Internal teeth 14 and external teeth 15, both of which mesh with each other, are formed with helical teeth. Also, this tube The front end edge of the front gear component 10a of the shaped gear 10 has a regulating ring on the inner surface of the cover 7. The movement in the maximum forward direction (to the left in the figure) is restricted by hitting the ring part 16; The rear end edge of the rear gear component 10b abuts against the inner end surface of the annular portion 5a, and the maximum rearward direction Movement in the right direction (in the figure) is restricted.

[0014] The gear drive mechanism 11 is formed between the front gear component 10a and the cover 7. A first hydraulic circuit 18 that supplies and discharges hydraulic pressure to and from the pressure chamber 17, and a rear gear configuration. A compression spring is elastically loaded between the portion 10b and the annular portion 5a and urges the cylindrical gear 10 forward. It mainly consists of a puller 19.

[0015] The first hydraulic circuit 18 branches from the oil main gallery 20 and connects to the cylinder. vertical direction formed in the head 2, the inside of the cam bearing 2a, and the radial direction of the camshaft 1 A passage 18a is bored in the direction of the internal central axis of the camshaft 1 and the mounting bolt 6. Along the axial passage 18b, the head side of the mounting bolt 6, and the radial direction of the holding member 5. The radial direction is formed continuously and connects the axial passage 18b and the pressure chamber 17. and a hole 18c. Further, a three-way type nozzle is provided at the upstream end of the vertical passage 18a. 1 solenoid valve 21 is provided, and this first solenoid valve 21 is connected to a crank angle sensor (not shown). The operating status of the engine is determined based on the output signals from each sensor such as the sensor and air flow meter. ON (energized) - OFF (de-energized) by the computer unit 22 that detects controlled.

[0016] The camshaft 1 is disposed between the holding member 5 and the sprocket body 8. A regulating means is provided for regulating an intermediate rotational position when rotating relative to the sprocket 3. There is.

[0017] As shown in FIGS. 2 to 4, this regulating means is located at the outer peripheral end of the annular portion 5a of the holding member 5. A cylinder hole 23 bored along the radial direction, and a cylinder hole 23 that can be freely slid into the cylinder hole 23. The locking piston 24 housed in the inner periphery of the rear end 8b of the sprocket body 8 A regulating hole 25 bored at a position substantially facing the cylinder hole 23 and the piston 2 4 and an actuating mechanism 26 that moves the engine forward and backward according to the engine operating state.

[0018] The cylinder hole 23 has a substantially elliptical long groove 27 in the upper end on the lower end side in the circumferential direction. The inner diameter is set slightly larger than the outer diameter of the piston 24. In addition, the depth dimension is set slightly deeper than the length of the piston 24. . The long groove 27 has the same length in the left and right directions in the circumferential direction around the cylinder hole 23. In addition to being extended, its width is set slightly larger than the outer diameter of the piston 24. It is.

[0019] The piston 24 has a cylindrical shape, and the circumferential edges of the upper and lower ends are chamfered in an R shape. At the same time, its length extends across both the cylinder hole 23 and the regulation hole 25 at the time of maximum advancement. The length is set to fit. Further, the regulation hole 25 is connected to the cylinder hole 23. They are set to the same inner diameter.

[0020] The actuation mechanism 26 includes a plunger slidably housed in the regulation hole 25. 28 , and a pressure receiving chamber 29 formed between the lower end of the cylinder hole 23 and the piston 24 A second hydraulic circuit 30 is provided for supplying and discharging hydraulic pressure to and from.

[0021] The outer diameter of the plunger 28 is set to be approximately the same as the outer diameter of the piston 24. In addition, its length is set shorter than the length of the regulation hole 25. Also this program The plunger 28 has a compression spring loaded between the bottom surface and the bottom surface of the regulation hole 25. The front end surface 28a is biased in the direction of the long groove 27 by the spring force of 31, and the front end surface 28a It is always in contact with 24a. The compression spring 31 has a low pressure inside the pressure receiving chamber 29. When the pressure is applied, the piston 24 is pushed through the plunger 28 and completely inserted into the cylinder hole 23. The spring force is set to the extent that it can be stored in the

[0022] The second hydraulic circuit 30 is formed approximately parallel to the first hydraulic circuit 18, and has an oil main. branched from the engine gallery 20 to the cylinder head 2, the inside of the cam bearing 2a, and the camshaft. A longitudinal passage 30a formed along the inner diameter direction of the camshaft 1 and a longitudinal passage 30a formed along the inner diameter direction of the camshaft 1 It is formed continuously in the internal axial direction and inside the annular portion 5a, and is further bent in the radial direction. It has a communication passage 30b that communicates the vertical passage 30a and the pressure receiving chamber 29. Ma In addition, at the upstream end of the vertical passage 30a, there is an ON connection from the computer unit 22. A three-way type second solenoid valve 32 that is controlled by the -OFF signal is provided.

[0023] Note that the first and second solenoid valves 21 and 32 are equipped with oil in the pressure chamber 17 and the pressure receiving chamber 29. Drain passages 33a and 33b discharge pressure to the outside via each hydraulic circuit 18 and 30. It is provided. In addition, the upper wall of the regulating hole 25 is provided to prevent leakage into the regulating hole 25. A discharge hole 3 for discharging oil to the outside to lubricate the tooth portion 9 and the timing chain. 4 is provided.

[0024] The operation of this embodiment will be explained below.

[0025] First, in the engine low load range, the computer is connected to the first solenoid valve 21 and the second solenoid valve 32. An OFF signal (de-energized) is output from the unit 22, and each hydraulic circuit 18, 30 is activated. The supply of hydraulic pressure to the pressure chamber 17 and the pressure receiving chamber 29 is stopped. therefore , the cylindrical gear 10 is maintained at the leftmost position shown in FIG. 1 by the spring force of the compression spring 19. , and the camshaft 1 is at such a relative rotational position with respect to the sprocket 3, that is, the intake It is held in a rotational position that delays the closing of the valve.

[0026] On the other hand, as shown in FIG. 28 is pushed out by the spring force of the compression spring 31, and the front end fits into the long groove 27. While doing so, the piston 24 is pressed with the front end surface 28a. Therefore, the piston 24 It is held in the retracted position completely housed within the cylinder hole 23.

[0027] Also, when the load range changes from low to high, an ON signal is output to the first solenoid valve 21. The OFF signal remains output to the second solenoid valve 32. Therefore, The hydraulic oil pressure-fed from the oil pump 34 does not flow into the second hydraulic circuit 30, but instead flows into the first hydraulic circuit 30. Only the hydraulic circuit 18 flows in and is supplied to the pressure chamber 17, and the internal pressure of the pressure chamber 17 increases. On the other hand, the inside of the pressure receiving chamber 29 maintains a low pressure state. Therefore, the pressure inside the pressure chamber 17 As it rises, the entire cylindrical gear 10 resists the spring force of the compression spring 19 and moves backward to the maximum. Moving. Therefore, the camshaft 1 and the holding member 5 are moved together as shown in FIG. Rotate the intake bar to its maximum relative to the proket 3 in the clockwise direction (direction of the arrow) in the figure. It is held in a position that delays the closing timing of the valve.

[0028] Here, while the piston 24 is being pressed by the plunger 28, the tip surface 24a and the front The end surface 28a moves in sliding contact with the rotation of the holding member 5.

[0029] Furthermore, the engine operating state will shift from the low load range or high load range to the medium load range. In this case, while an ON or OFF signal is output to the first solenoid valve 21, An ON signal is output to the second solenoid valve 32. Therefore, the oil is pumped from the oil pump 34. The hydraulic oil is supplied into the pressure receiving chamber 29 through the second hydraulic circuit 30, and the hydraulic fluid is supplied into the pressure receiving chamber 29 through the second hydraulic circuit 30. As the pressure inside 29 increases, the piston 24 and and push up the plunger 28. For this reason, camshaft 1 and sprocket 3 When the cylinder hole 23 and the regulating hole 25 match during relative rotation, the piston 24 Move the plunger 28 forward as shown in FIG. 4 and hit the bottom of the regulation hole 25. Push up until the tip 24a of the piston 24 is in the regulating hole 25. to intervene. Therefore, free relative rotation between the holding member 5 and the sprocket body 8 is regulated. The camshaft 1 is held securely in the intermediate relative rotation position. As a result, medium negative It is possible to obtain stable and reliable valve timing control in loading areas, etc. .

[0030] In addition, if the operating state shifts to a lower load range or a higher load range, An OFF signal is output to the second solenoid valve 32, and the supply of pressure oil to the pressure receiving chamber 29 is stopped. At the same time, the pressure oil in the pressure receiving chamber 29 flows back through the second hydraulic circuit 30 and drains. It is immediately discharged from the air passageway to the outside. Therefore, the piston 24 is a compression spring. The camshaft is quickly moved backward into the cylinder hole 23 by the spring force of the camshaft 31. 1 and sprocket 3 can be smoothly rotated relative to each other.

[0031] Note that when the second solenoid valve 32 is in the OFF state, the spring force of the compression spring 31 Since the plunger 28 is pressing the piston 24, there is friction between the two 24 and 28. Resistance is occurring. Therefore, the camshaft 1 Sudden forward and reverse rotations due to negative rotational torque fluctuations are sufficiently suppressed by the frictional resistance, Loud hitting noise between each tooth due to backlash of the cylindrical gear 10 due to the torque fluctuation etc. are prevented. In addition, if the piston 24 is inserted into the regulation hole 25, The piston 24 ensures the forward and reverse rotation of the camshaft 1 due to the torque fluctuation. Needless to say, it is regulated by

[0032] The present invention is not limited to the configuration of the above embodiment, but the phase conversion means is formed into a cylindrical shape. It may also be possible to use a clutch mechanism or the like instead of gears, and the actuation mechanism 2 The piston 24 and plunger 28 of 6 are operated by hydraulic pressure instead of the spring force of the compression spring 31. It is also possible to restrict movement. In addition, this device can be used not only for intake valves but also for exhaust valves. It is also possible to apply it to air valves or both intake and exhaust valves.

[0033]

[Effect of the idea]

As is clear from the above explanation, according to the present invention, the piston can be adjusted according to the engine operating condition. The camshaft is then moved from the cylinder hole to the regulation hole via the operating mechanism. Since the relative rotational position of the camshaft and the rotating body is restricted, Not only can the relative rotational position be controlled in three stages, but the intermediate relative rotational position can be reliably controlled. It becomes possible to regulate the As a result, valve timing can be adapted to engine operating conditions. can be controlled stably and with high precision.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a valve timing control device according to the present invention.

FIG. 2 is an action explanatory diagram showing a cross section taken along line AA in FIG. 1;

FIG. 3 is another action explanatory diagram showing a cross section taken along line A-A in FIG. 1;

FIG. 4 is a still different explanatory diagram showing a cross section taken along line AA in FIG. 1;

[Explanation of symbols]

1...Camshaft, 3...Sprocket (rotating body), 4...
Phase conversion means, 5... holding member, 8... sprocket body,
23...Cylinder hole, 24...Piston, 25...Regulation hole,
26...Operating mechanism.

Claims (1)

[Scope of utility model registration request] [Claim 1] A rotating body to which driving force is transmitted from an engine;
In a valve timing control device that controls the opening and closing timing of the valve by relatively rotating the camshaft that opens and closes the valve by the rotational force from the rotary body according to the engine operating state using a phase conversion means, the camshaft , a cylinder hole is provided inside to slidably accommodate a locking piston, and a regulating hole through which the tip of the piston advances or retreats is provided at a position facing the cylinder hole on the inner circumference of the rotating body. A valve timing control device for an internal combustion engine, further comprising an actuation mechanism for moving the piston forward and backward from the cylinder hole to the regulating hole according to engine operating conditions.