JPH04107417U - Internal combustion engine valve timing control device - Google Patents

Abstract

(57) [Summary] [Purpose] Eliminate cylindrical gears to obtain highly accurate and responsive valve timing control, improve manufacturing efficiency and reduce costs, and reduce the overall size of the equipment. This improves the freedom of layout within the engine room. [Structure] In a device that changes the relative rotational phase between the camshaft 1 and the driven pulley 3 to vary the opening/closing timing of intake valves, etc., an arm 4 is attached to one end 1a of the camshaft.
On the other hand, actuating mechanisms 6 and 7 are provided on the end wall 11a of the driven pulley 3 to cause the piston 14 to reciprocate within the cylinder 13 by a drive mechanism, thereby rotating the arm 4 in forward and reverse directions.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This invention adjusts the opening and closing timing of the intake valve or exhaust valve of an internal combustion engine according to the operating state. The present invention relates to a valve timing control device that performs variable control according to the 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. 4,231,330 is known. There is.

0003 To give you an overview, it is located at the front end of the camshaft that controls the opening and closing of the intake and exhaust valves. has external teeth formed on the outer periphery. On the other hand, there is a support located outside the front end of the camshaft. The engine's rotational force is transmitted to the outer periphery of the held outer cylinder via the timing chain. It is equipped with a sprocket and internal teeth are formed on the inner periphery. And this Between the inner teeth of the camshaft and the outer teeth of the camshaft, there is at least one of the teeth on the inner and outer circumferences. A cylindrical gear with helical teeth on one side meshes with the other, and this cylindrical gear is used for engine operation. The camshaft is controlled by the hydraulic pressure of the hydraulic circuit and the spring force of the compression spring depending on the rotational state. By moving the camshaft in the axial direction, the camshaft is moved relative to the sprocket. It is designed to rotate to control 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 sprocket and The camshaft is formed on at least one of the inner and outer circumferences of the cylindrical gear. The helical teeth are used to achieve relative rotation, but these helical teeth are not suitable for the sprocket. In order to ensure good meshing accuracy with the internal teeth of the camshaft or the external teeth of the camshaft, Precise processing is required. As a result, the machining work of the helical teeth becomes complicated and the manufacturing process becomes difficult. This has led to a decline in business efficiency and a rise in manufacturing costs.

[0005] In addition, the camshaft can only be moved by moving the cylindrical gear in the axial direction. Since it is designed to rotate relative to the sprocket, the cylindrical gear and the inner and outer teeth Due to the meshing friction resistance of the valve, a delay in its axial movement is likely to occur, and the valve Responsiveness of timing control tends to deteriorate.

[0006] Moreover, the cylindrical gear extends in the axial direction of the camshaft, and the cylindrical gear extends in the axial direction of the camshaft. Since the valve timing control device has a large displacement, it is necessary to Requires storage space. As a result, internal combustion engines have been forced to become larger and This limits the freedom of layout within the room.

[0007]

[Means to solve the problem]

The present invention was devised in view of the above-mentioned conventional problems, and in particular, the camshaft An arm is provided at the end of the rotor, while a shaft is provided along the radial inner surface of the rotor. The piston is slidably housed in the cylinder, and one end is connected to the piston. Connect the other end of the connected rod to the end of the arm from a direction substantially perpendicular to the axis. and further provided with a drive mechanism that slides the piston according to the engine operating state. It is characterized by

[0008]

[Effect]

For example, in a low engine load range, the drive mechanism moves the piston to the lowest position of the cylinder. Press down until Therefore, the piston is connected via the connecting rod. Push the end of the drum and rotate it to the maximum in one direction. This causes the camshaft to rotate. It rotates in one direction relative to the rolling body to change the phase, for example to delay the closing timing of the intake valve. control on the opposite side.

[0009] On the other hand, when the engine shifts to a high load range, for example, the piston is moved by the drive mechanism. Push it up to the top position inside the cylinder. Therefore, the piston now connects Pull the end of the arm through the pulling rod to maximize rotation in the other direction. Therefore, the camshaft rotates relative to the other to change the phase, for example when the intake valve is closed. Control the period to advance.

0010

【Example】

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

[0011] Figures 1 to 3 show this idea applied to the intake valve side of an automobile's DOHC internal combustion engine. One embodiment is shown in which 1 is supported by a cam bearing 2 on the upper part of the cylinder head, and the intake valve is A camshaft that opens and closes the valve by a cam not shown, 3 is one end of the camshaft 1 A drive pulley is rotatably supported by 1a and attached to a crankshaft (not shown). Driven pulley is a rotating body to which rotational force is transmitted from the drive via the timing belt. An arm 4 is screwed onto one end 1a of the camshaft 1 from the axial direction. It is tightened and fixed with a mounting bolt 5. On the other hand, the inside of driven pulley 3 is provided with a pair of actuation mechanisms 6 and 7 for rotating the arm 4 in forward and reverse directions, The operating mechanisms 6 and 7 are driven by a drive mechanism according to the engine operating state. ing.

0012 The arm 4 is attached to one end 1a of the camshaft with a spacer 8 by a mounting bolt 5. A substantially disk-shaped base 9 is fixed via the camshaft 1 at both ends of the base 9. It includes protrusions 10, 10 provided along the diameter direction.

[0013] The driven pulley 3 includes a pulley body 11 in the shape of a covered cylinder and having gears on the outer periphery. , a disc-shaped cover portion fixed to the outer end side of the pulley body 11 with bolts not shown. It consists of 12. The pulley main body 11 has a central hole in a disc-shaped end wall 11a. The camshaft is rotatably supported by one end 1a of the camshaft via a cylindrical portion 11b provided on the periphery. ing.

[0014] As shown in FIGS. 2 and 3, the actuation mechanisms 6 and 7 are located inside the end wall 11a. A pair of cylinders 13 arranged in parallel in an offset state with the axis of the arm 4 sandwiched between the planes, 13, and pistons 14, 1 slidably provided in the cylinders 13, 13, respectively. 4, a connecting rod 15 connecting the pistons 14, 14 and the arm 4, 15. The cylinders 13, 13 have inner surfaces of the heads 13a, 13a. Pressure receiving chambers 16, 16 are formed between the pistons 14, 14 and the crown surfaces 14a, 14a. At the same time, the maximum downward movement of the pistons 14, 14 is applied to the lower inner periphery of the cylinder walls 13b, 13b. Annular step protrusions 13c, 13c are provided for regulating.

[0015] The connecting rods 15, 15 have one end at the lower end of the pistons 14, 14. Pistons 18, 18 supported by brackets 17, 17 in the Support pins 19, 1 are connected to each other, and the other ends are provided on the protrusions 10, 10 of the arm 4. 9, and are rotatably connected to each other.

[0016] The drive mechanism is formed by folding the lower portions of the pistons 14, 14 and the cylinder walls 13b, 13b. It is loaded between the curved lower ends 13d and 13d, and urges the pistons 14, 14 upward. Supplies and discharges hydraulic pressure to and from the compression springs 20, 20 and the pressure receiving chambers 16, 16. A hydraulic circuit 21 is provided. The compression springs 20, 20 are connected to the pressure receiving chamber 16. , 16 is a spring force that moves the pistons 14, 14 upward when the pressure is low and no hydraulic pressure is supplied to the pistons 14, 16. is set to .

[0017] The hydraulic circuit 21 is branched from the oil main gallery 22 as shown in FIG. a longitudinal passage 23 formed in the diametrical direction of the cam bearing 2 and the camshaft 1; A longitudinal passage 23 is formed continuously in the axial direction of the camshaft 1 and the mounting bolt 5. The axial passage 24 communicates with the mounting bolt 5, the spacer 8, and the inside of the cylinder 13 wall. Communication passages 25, 25 are formed in and communicate the axial passage 24 and the pressure receiving chambers 16, 16. It has Also, at the upstream end of the vertical passage 23, pressure is supplied from the oil pump 26. The supplied hydraulic oil is supplied and stopped by the output signal from the electronic controller 27. A three-way type solenoid valve 28 is provided. The electronic controller 27 is not shown in the figure. Based on the output signals from the crank angle sensor, air flow meter, etc. The solenoid valve 28 is turned on and off by detecting the operating state of the valve. In addition, solenoid valve 28 A drain is provided for discharging the hydraulic oil in the pressure receiving chambers 16, 16 to the outside via the hydraulic circuit 21. A passageway 29 is provided.

[0018] The operation of this embodiment will be explained below.

[0019] First, for example, in a low engine load range, the solenoid valve is activated by a signal from the electronic controller 27. 28 is turned off and becomes de-energized, and the oil main gallery 22 and the vertical passage 23, while allowing the vertical passage 23 and the drain passage 29 to communicate with each other. Therefore, the pressure inside the pressure receiving chambers 16, 16 becomes low, and the compression springs 20, 20 At the same time as the force pushes up the pistons 14, 14, the hydraulic oil in the pressure receiving chambers 16, 16 is released. The water flows backward through each passage 23, 24, 25 and is quickly discharged to the outside from the drain passage 29. It will be done. Therefore, each piston 14, 14 has a crown surface 14a, 1 as shown in FIG. 4a moves upward to the maximum raised position where it hits the inner surface of the cylinder heads 13a, 13a. Then, connect the entire arm 4 to the clock via the connecting rods 15, 15 as shown in the figure. direction. Therefore, the camshaft 1 is connected to the driven pulley 3. By relatively rotating clockwise, the closing timing of the intake valve is controlled to the delayed side.

[0020] Note that the camshaft 1 has positive and negative forces due to the spring force of the valve spring, etc. If a sudden rotational torque fluctuation occurs, the pistons 14, 14 will move to the stepped portion 13. c, 13c and the hydraulic pressure in the pressure receiving chambers 16, 16 reliably regulate vertical movement. Therefore, sudden forward and reverse rotation of the camshaft 1 is suppressed.

[0021] On the other hand, when the engine operating state shifts from a low load range to a high load range, the electronic control The solenoid valve 28 is turned on by the signal from the oil main gallery 22. and the vertical passage 23 are communicated with each other. Therefore, the oil pumped from the oil pump 26 is The hydraulic oil passes through the vertical passage 23, the axial passage 24, and the communication passages 25, 25 to each pressure receiving area. It is supplied into the chambers 16, 16, and increases the internal pressure of each pressure receiving chamber 16, 16. others As shown in FIG. Resisting the spring force, the lower end edge of the cylinder wall 13b, 13b has a stepped portion 13c, 13c. Each connecting rod 15, The protrusions 10, 10 are pushed from opposite directions via the pins 15, and the entire arm 4 is Rotate counterclockwise as shown. Therefore, the camshaft 1 is - rotates counterclockwise relative to the intake valve 3 to control the closing timing of the intake valve to the advance side. Ru.

[0022] Also, here, similar to the above, positive and negative rotational torque fluctuations occur on the camshaft 1. Even if the pistons 14, 14 are connected to the inner surfaces of the heads 13a, 13a and the compression spring 20, , 20, the vertical movement is restricted by the spring force of the camshaft 1, so that the forward and reverse rotation of the camshaft 1 is prevented. suppressed.

[0023] Further, the arm 4 is provided in the diametrical direction of the camshaft 1, and each operating mechanism 6, 7 is also provided along the end wall 11a, so when using a cylindrical gear as in the past, In comparison, the axial length of the device can be made sufficiently short.

[0024] Moreover, the actuation mechanism 6, 7 is made up of a single unit consisting of cylinders 13, 13 and pistons 14, 14. Due to its simple structure, the elimination of cylindrical gears also simplifies the entire device. As a result, manufacturing efficiency can be improved and manufacturing costs can be reduced.

[0025] Furthermore, since the sliding resistance between the cylinders 13, 13 and the pistons 14, 14 is small, The relative rotation of the camshaft 1 is quickly changed in response to changes in engine operating conditions. be able to.

[0026] It should be noted that the present invention is not limited to the above embodiments, and for example, the piston 14, 14 is not compressed by the compression springs 20, 20, but by providing a separate hydraulic circuit and using hydraulic pressure. It is also possible to make the device reciprocate, and the device can also be used as an exhaust valve or an intake/exhaust valve. It is also possible to provide both valves.

[0027]

[Effect of the idea]

As is clear from the above explanation, according to the present invention, the camshaft and the rotating body Rather than using a conventional cylindrical gear to rotate, the piston inside the cylinder is controlled via a drive mechanism. Since this is done by reciprocating the Not only can accurate and responsive valve timing control be obtained, but especially Since no helical teeth are required, the structure is simplified, improving manufacturing efficiency and reducing costs. can be achieved.

[0028] Furthermore, the length of the device in the axial direction can be made as short as possible, and the overall size can be reduced. child As a result, the degree of freedom in the layout within the engine room of an internal combustion engine equipped with this device is increased. improves.

[0029] Furthermore, the camshaft is relatively rotated by movement of a piston in a cylinder. This structure further simplifies the structure and improves durability.

[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 a view taken along arrow A in FIG. 1 showing the operation of this embodiment.

FIG. 3 is a view taken along arrow A in FIG. 1 showing another effect of this embodiment.

[Explanation of symbols]

1...Camshaft, 3...Driven pulley (rotating body), 4
... Arm, 6, 7... Operating mechanism, 13... Cylinder, 14...
Piston, 15... Connecting rod, 20... Compression spring (drive mechanism), 21... Hydraulic circuit (drive mechanism).

Claims (1)

[Scope of utility model registration request] 1. A valve timing control device that variably controls the opening and closing timing of a valve by rotating a rotating body to which the driving force of an engine is transmitted and a camshaft relative to each other in forward and reverse directions, the end portion of the camshaft is provided with an arm, and in a cylinder provided along the radially inner surface of the rotating body,
The piston is slidably housed, and the other end of the connecting rod, whose one end is connected to the piston, is connected to the end of the arm from a direction substantially perpendicular to the axis, and the piston is slidably accommodated depending on the engine operating state. 1. A valve timing control device for an internal combustion engine, comprising a drive mechanism for moving the valve timing.