JPH07189622A - Valve timing adjusting device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a valve timing adjusting device for an internal combustion engine that is compact, has excellent durability, and has low noise. [Structure] A drive cylinder 14 rotatably fitted to a tip end of a cam shaft 12, and a gear 18 provided on the drive cylinder 14.
A timing adjusting motor 16 which has a drive gear 17 meshing with the gear 18 and is attached to the front end side of the cylinder head 11, an internal thread cylinder 25 screwed into the drive cylinder 14, and an internal thread cylinder 25. A rotation stopping means that is mounted between the cylinder head 11 and restrains the rotation of the female screw cylinder 25, an intermediate cylinder 36 that is rotatably connected to the tip of the female screw cylinder 25, and an inner circumference on the outer circumference of the intermediate cylinder 36. Is integrally connected to the distal end of the cam shaft 12 and a cylindrical pulley 35 that is screwed through a multi-thread screw 38 and is driven by the engine, and the outer circumference of the intermediate cylinder 36 has a reverse lead. The extension cylinder 31 is screwed through the multi-thread screw 37.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve timing adjusting device for an internal combustion engine capable of continuously changing the opening / closing timing of intake / exhaust valves by a motor.

[0002]

2. Description of the Related Art An internal combustion engine (hereinafter simply referred to as an engine) mounted on an automobile is required to flexibly cope with a very large rotation change and load change. From this point of view, the opening / closing timing of the intake / exhaust valve is changed according to the operating state of the vehicle so that stable and efficient output characteristics can always be obtained regardless of the load on the engine or the rotation speed of the engine. Such a structure is proposed in, for example, Japanese Patent Laid-Open No. 5-79306.

The valve timing adjusting device for an internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 5-79306 has a housing protruding from the end of a cylinder head, and a ball nut coaxial with the cam shaft is provided in the housing. A ball screw shaft, which is rotatably housed and screwed into this ball nut in a penetrating state, is arranged in a straight line with the cam shaft, and a phase changing member and a cam shaft rotatably connected to this ball screw shaft. The end of the ball screw shaft is connected via a multiple thread and the ball nut is rotated by an electric motor to displace the ball screw shaft together with the phase changing member in the direction opposite to the cam shaft. The cam shaft is forcibly rotated by a multi-thread screw.

[0004]

[Patent Document 1] Japanese Patent Application Laid-Open No. 5-79306
In the conventional valve timing adjusting device disclosed in Japanese Patent Publication, since the housing that houses the ball nut and the ball screw shaft and the electric motor need to be arranged in a protruding state at one end of the cylinder head, the overall length of the engine is long. It causes layout problems.

Further, since the ball screw shaft, the ball nut, and the like largely protrude from one end of the cylinder head, and a heavy electric motor is attached to the housing,
Some measures must be taken to increase the rigidity of the housing, and the bending force associated with the vibration of the engine acts on the phase changing member and the like, and the effect thereof impairs the smooth operation of the phase changing member. For this reason, it is necessary to form a relatively large amount of play in the part of the multiple thread between the phase changing member and the cam shaft, but this part of play causes abnormal noise due to torque fluctuations of the engine. , Becomes one of the causes of noise when the engine is operating.

Further, since the above-mentioned torque fluctuation of the engine acts on the ball screw shaft side from the cam shaft side through the phase changing member, the screwed state of the ball screw shaft and the ball nut deteriorates, and its durability is improved. There is a flaw that damages.

[0007]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a valve timing adjusting device for an internal combustion engine which is compact, excellent in durability and low in noise.

[0008]

A valve timing adjusting device for an internal combustion engine according to the present invention includes a drive cylinder rotatably fitted to a tip end portion of a camshaft, and a gear integrally provided on the drive cylinder. , A timing adjusting motor having a drive gear that meshes with this gear and attached to the side of the front end of the cylinder head, a female screw cylinder screwed into the drive cylinder, and between the female screw cylinder and the cylinder head. A rotation stopping means that is attached to restrain the rotation of the female screw cylinder, an intermediate cylinder that is rotatably connected to the distal end portion of the female screw cylinder, and an inner periphery of the intermediate cylinder that is screwed onto the outer periphery of the intermediate cylinder through a multiple thread screw. And a tubular pulley driven by an engine and integrally connected to the tip of the cam shaft, and having an outer circumference on the inner circumference of the intermediate cylinder via the multithread screw of the reverse lead and the multithread screw. Equipped with an extension tube to be screwed And it is characterized in and.

Here, it is also effective to further include a backlash removing means for removing the play of the two sets of the multi-threaded screw, and it is also effective to extend the axial direction of the intermediate cylinder to the intermediate cylinder. You may make it further provide the communicating oil path which opens at both end surfaces.

[0010]

With the operation of the engine, the pulley is driven, and the rotation of the pulley is transmitted to the cam shaft integrated with the extension cylinder via the intermediate cylinder, and the cam shaft is driven in synchronization with the engine.

When the timing adjusting motor is operated to transmit the rotational force from the drive gear to the gear of the drive cylinder, the rotation of the female screw cylinder screwed with the drive cylinder is restricted by the rotation stopping means. It moves in a direction parallel to the axis of the cam shaft as the drive cylinder rotates. Since the intermediate cylinder is connected to the female threaded cylinder, this intermediate cylinder also moves in the direction parallel to the axis of the cam shaft, but multithreaded screws with opposite leads are formed on the inner circumference and the outer circumference of the intermediate cylinder. Therefore, the rotation phase of the pulley and the rotation phase of the cam shaft integrated with the extension cylinder are shifted as the intermediate cylinder moves. That is, the rotation phase of the cam shaft with respect to the engine is deviated by the operation of the timing adjusting motor, and the opening / closing timing of the intake / exhaust valve that is linked to the rotation of the cam shaft is changed.

On the other hand, since the timing adjusting motor is attached to the cylinder head side, the protrusion amount of the valve timing adjusting device from the cylinder head is reduced.

In the case of having the backlash removing means, as a result of the backlash removing means always urging the intermediate cylinder in one direction, the flanks of the multiple thread screw formed on the inner and outer circumferences of the intermediate cylinder have a cylindrical shape. The flanks of the multi-threaded screw formed on the pulley and the extension cylinder are in pressure contact with each other. Also,
With a communication oil passage that opens at both ends of the intermediate cylinder,
Lubricating oil is supplied to the inside of the device through the communication oil passage.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a valve timing adjusting device for an internal combustion engine according to the present invention will be described in detail with reference to FIGS.

A drive cylinder 14 having a spiral oil groove 13 formed on an inner peripheral surface thereof is fitted to a tip end portion of a cam shaft 12 rotatably held in a cylinder head 11 so as to be relatively rotatable.
A reduction bevel gear 18 that meshes with a drive bevel gear 17 of a timing adjusting motor 16 that is fixed to the tip of the cylinder head 11 via a bolt 15 is integrally formed at the base end of the drive cylinder 14. Has been formed.

The controller 19 for controlling the operation of the timing adjusting motor 16 includes a crankshaft angle sensor 20 for detecting the rotation speed of a crankshaft (not shown) and a water temperature sensor for detecting the cooling water temperature of the engine (not shown). 21, a boost pressure sensor 22 for detecting the load of the engine based on the negative pressure in the intake passage (not shown), a vehicle speed sensor 23 for detecting the running speed of the vehicle, and the like, which are stored in advance based on the operating state of the vehicle From camshaft 1
2 and the target phase of the crankshaft are read. The rotation amount of the drive bevel gear 17 is adjusted so that the camshaft 12 and the crankshaft match the target phase. Therefore, in this embodiment, the cam shaft angle sensor 60 (see FIG. 3) for detecting the rotational phase of the cam shaft 12 is assembled to the cam shaft 12, and the detection signal from the cam shaft angle sensor 60 is sent to the controller 19. It is supposed to be output.

The male screw portion 24 formed on the front end side of the drive barrel 14 has a female screw portion 26 formed on the front end portion of a female screw barrel 25 rotatably fitted to the drive barrel 14.
Are screwed together. At the base end of the female screw cylinder 25, two notches 27 are engraved in parallel with the axis of the cam shaft 12 at 180 degrees apart from each other, and each notch 27 is slidable. The detent pins 28 that engage with are fixed to the inside of the tip end portion of the cylinder head 11 via bolts 29, respectively.

Therefore, when the timing adjusting motor 16 is driven, the reduction bevel gear 18 rotates together with the drive cylinder 14 via the drive bevel gear 17. Here, since the female screw cylinder 25 that is screwed into the drive cylinder 14 is engaged with the detent pin 28 and cannot rotate, the direction parallel to the axis of the cam shaft 12 is accompanied by the rotation of the drive cylinder 14. It is designed to move back and forth (left and right in the figure). That is, the notch 27, the detent pin 28, and the like constitute the detent means in the present invention, but in short, as long as the female screw cylinder 25 does not rotate as the drive cylinder 14 rotates, Not limited to the embodiment, it is naturally possible to adopt other well-known detent means.

An oil hole 30 is formed in the central portion of the female screw cylinder 25 so as to communicate with the outer peripheral side of the female screw cylinder 25 and the male screw portion 24 side of the drive cylinder 14.

A base end portion of a cylindrical extension cylinder 31 is integrally fitted to the tip end of the cam shaft 12 via a bolt 32 screwed into the cam shaft 12, and the base end surface of the extension cylinder 31 is attached to the base end surface of the extension cylinder 31. The oil groove 33 communicating with the above-mentioned spiral oil groove 13 is engraved in the radial direction. A toothed belt (not shown) is wound around a toothed pulley 35, which surrounds the extension cylinder 31 and the tip end side of the female screw cylinder 25 with a boss portion 34, and the toothed pulley 35 is not shown via the toothed belt. It is designed to rotate synchronously with the crankshaft of the engine.

An intermediate cylinder 36 is interposed between the boss portion 34 of the toothed pulley 35 and the extension cylinder 31. Between the inner circumference of the intermediate cylinder 36 and the outer circumference of the extension cylinder 31, a multi-thread screw 37 that is screwed into each other is formed.
A multi-thread screw 38 is also formed between the outer circumference of the intermediate cylinder 36 and the inner circumference of the boss portion 34 so as to be screwed together. These two sets of multi-thread screws 37, 38 are leads that are opposite to each other. In this embodiment, the multi-thread screw 37 on the extension cylinder 31 side is set to the left thread, and the multi-thread screw 37 on the toothed pulley 35 side is set. The thread 38 is set to the right. Further, between the inner circumference of the rear end portion of the intermediate cylinder 36 and the outer circumference of the tip end portion of the female screw cylinder 25, the female screw cylinder 2
Angular ball bearings 39 that allow relative rotation of the intermediate cylinder 36 with respect to No. 5 are interposed, and are in a state of being connected to each other by retaining rings 40 and 41, respectively.

In this embodiment, the angular contact ball bearing 39 is integrated with the female screw cylinder 25 in a press-fitted state.
In the intermediate cylinder 36, a plurality of communication oil passages 42 that open on the front end surface side and the base end surface side of the intermediate cylinder 36 are provided with a plurality of communication oil passages 42.
It is formed parallel to the axis line of. Thereby, the intermediate cylinder 3
When 6 is displaced in the left-right direction in FIG. 1, the movement of the lubricating oil filling both sides of the intermediate cylinder 36 is smoothly performed through the communication oil passage 42, and the intermediate cylinder 36 is smoothly moved without resistance of the lubricating oil. It can be moved. In place of the communication oil passage 42, at least one of the threads of the multi-thread screws 37, 38 may be partially removed over its entire length, and this may be used as a communication oil passage to obtain the same effect. Obtainable.

An annular cover 43 having an outer peripheral portion integrally caulked at the tip of the boss portion 34 of the toothed pulley 35.
The distal end portion of the extension cylinder 31 is fitted in the inner peripheral portion of the above in a penetrating state, and the retaining ring 44 attached to the tip end of the extension cylinder 31 prevents the cover 43 from coming off. Also,
The tip surface of the cover 43 has a boss portion 3 of the toothed pulley 35.
A circular lid plate 45 that closes the inside of 4 is integrally screwed through a bolt 46.

Therefore, as described above, with the movement of the female screw cylinder 25 in the direction parallel to the axis of the cam shaft 12, the intermediate cylinder 3
6 also moves integrally with this in a direction parallel to the axis of the camshaft 12. At this time, since the intermediate cylinder 36 is screwed to the extension cylinder 31 and the boss portion 34 of the toothed pulley 35 by the two sets of multi-thread screws 37 and 38 whose leads are opposite to each other,
The relative phase between the extension cylinder 31 and the boss portion 34 of the toothed pulley 35 is shifted in correspondence with the leads of the multiple thread screws 37, 38. As a result, the rotational phase of the crank angle deviates from the rotational phase of the camshaft 12, and the opening / closing timing of the intake / exhaust valve (not shown) changes.

Although a stepping motor is used as the timing adjusting motor 16 in this embodiment,
A DC motor or the like can also be used. Also, the bevel gear 1
It is also possible to employ worms and worm wheels instead of 7,18. When a worm and a worm wheel are used, a non-reciprocal rotation state is naturally realized, so that the rotation phase of the drive cylinder 14, that is, the crankshaft and the camshaft 12, can be achieved without using a special lock mechanism. It is possible to maintain the rotation phase of the above in a state where the energization state to the timing adjustment motor 16 is cut off.

On the other hand, the tip end of the cylindrical holder 47 which surrounds the female screw cylinder 25 with a gap therebetween is provided with the toothed pulley 35 described above.
The base end of the boss portion 34 is integrally caulked. A seal ring 48 for sealing the inside of the cylinder head 11 is interposed between the outer periphery of the base end of the holder 47 and the tip of the cylinder head 11.

A coil-shaped compression spring 49 is interposed between the base end surface of the intermediate cylinder 36 and the holder 47, and the spring force of the compression spring 49 causes the boss portion 3 of the toothed pulley 35.
The play of the multi-thread screw 38 between 4 and the intermediate tube 36 is eliminated. Further, a disc spring-shaped compression spring 50 is also interposed between the cover 43 integrated with the toothed pulley 35 and the extension cylinder 31, and the spring force of the compression spring 50 causes the boss portion 34 of the toothed pulley 35. Multi-threaded screw 3 between the intermediate cylinder 36 and
In addition to the play of No. 8, the play of the multiple thread 37 between the extension cylinder 31 and the intermediate cylinder 36 is also removed.

As described above, in this embodiment, two compression springs are used as the backlash removing means, but in short, it is only necessary to have a structure capable of removing the play of the two sets of multi-thread screws 37, 38. The present invention is not limited to this example.

On the tip end side of the extension cylinder 31, there are radially formed oil holes 51 which communicate with a gap formed between the cover 43 and the tip end surface of the intermediate cylinder 36. Further, an oil passage 53 extending from the bolt hole 52 is formed at the tip of the cam shaft 12, and the oil passage 53 is formed at the center of the bolt 32 that integrally connects the extension cylinder 31 and the cam shaft 12. A communication oil passage 54 that communicates the passage 53 with the inside of the extension cylinder 31 is formed in a penetrating state. The oil passage 53 described above is provided with a connection oil passage 56 that connects the oil passage 53 and an annular oil groove 55 formed on the outer peripheral surface of the cam shaft 12, and the annular oil groove 55 is provided with an internal oil passage 55. A throttle ring 58, which is mounted on the open end of the oil passage 57 formed in the above and functions as an orifice, is connected. Further, an oil pump 59 driven by an engine is connected to the oil passage 57, and the lubricating oil discharged from the oil pump 59 is transferred from the oil passage 57 to the annular oil groove 55, the connecting oil passage 56, the oil passage 53, the communicating oil. Through the passage 54, the oil hole 51, and the communication oil passage 42,
It is supplied to the angular contact ball bearing 39, and is further supplied from the oil hole 30 between the drive cylinder 14 and the female screw cylinder 25, and via the oil groove 33 by the spiral oil groove 13 between the cam shaft 12 and the drive cylinder 14. The surplus lubricating oil is discharged to the cylinder head 11 side from the gap between the female screw cylinder 25 and the holder 47.

The torque fluctuation of the engine is transmitted from the toothed pulley 35 to the intermediate cylinder 36 side, and the intermediate cylinder has a compression spring 4
The portions of the multi-threaded screws 37, 38 are held in a play-free state by 9, 50, and the above torque fluctuation is absorbed by the elastic deformation of the compression springs 49, 50. Therefore, the generation of abnormal noise due to the torque fluctuation of the engine is suppressed.

In this embodiment, the crankshaft is rotated by the toothed pulley via the toothed belt, but when a chain is used, it is necessary to use a sprocket instead of the toothed pulley. is there.

[0032]

According to the valve timing adjusting device for an internal combustion engine of the present invention, the timing adjusting motor is provided at the front end of the cylinder head, and the drive cylinder driven by the timing adjusting motor is rotated at the tip of the camshaft. Since they are freely fitted, the length of the portion protruding from the front end of the cylinder head can be made significantly shorter than that of the conventional one, and the cylinder head can be made compact. In addition, since the rotating portion has a structure in which bending moments along these axes do not act, power transmission is extremely smooth and the durability of parts can be improved.

When a compression spring is attached between the cam shaft and the cylindrical pulley to remove the play of the multiple thread formed on the inner peripheral side and the outer peripheral side of the intermediate cylinder, The torque deformation of the engine can be absorbed by the elastic deformation and sliding frictional resistance of these compression springs.

Further, in the one having the communication oil passage penetrating the intermediate cylinder, since this communication oil passage functions as a passage for the lubricating oil for lubricating the inside of the apparatus, the intermediate cylinder is moved to change the valve timing. At this time, the lubricating oil interposed on the moving direction side of the intermediate cylinder can be released to the opposite side via the communication oil passage, and the valve timing switching responsiveness can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of a valve timing adjusting device for an internal combustion engine according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a cutaway view showing the shape of the right side surface of FIG.

[Explanation of symbols]

 11 Cylinder Head 12 Cam Shaft 13 Helical Oil Groove 14 Drive Tube 15 Bolt 16 Timing Adjustment Motor 17 Drive Bevel Gear 18 Reduction Bevel Gear 19 Controller 20 Crankshaft Angle Sensor 21 Water Temperature Sensor 22 Boost Pressure Sensor 23 Vehicle Speed Sensor 24 Male Thread 25 Female Thread Cylinder 26 Female screw part 27 Notch part 28 Detent pin 29 Bolt 30 Oil hole 31 Extension cylinder 32 Bolt 33 Oil groove 34 Boss part 35 Toothed pulley 36 Intermediate cylinder 37, 38 Multiple thread 39 Angular contact ball bearing 40, 41 Stop ring 42 communication oil passage 43 cover 44 retaining ring 45 cover plate 46 bolt 47 holder 48 seal ring 49, 50 compression spring 51 oil hole 52 bolt hole 53 oil passage 54 communication oil passage 55 annular oil groove 56 connection oil passage 57 oil passage 58 throttle Wheel 59 Oil pump 60 Cam shaft angle Capacitors

Claims (3)

[Claims] 1. A front end of a cylinder head, comprising: a drive cylinder rotatably fitted to a tip end portion of a cam shaft; a gear integrally provided on the drive cylinder; and a drive gear meshing with the gear. A timing adjusting motor that is attached to the side, an internal thread cylinder that is screwed into the drive cylinder, a detent means that is installed between the internal thread cylinder and the cylinder head, and that restrains rotation of the internal thread cylinder, An intermediate cylinder rotatably connected to the tip of the female screw cylinder; a cylindrical pulley whose inner circumference is screwed onto the outer circumference of the intermediate cylinder via a multiple thread screw and which is driven by an engine; Of the internal combustion engine, which is integrally connected to the tip of the intermediate cylinder, and has an extension cylinder whose outer circumference is screwed onto the inner circumference of the intermediate cylinder through the multi-thread screw of the reverse lead. Valve timing adjustment device. 2. The valve timing adjusting device for an internal combustion engine according to claim 1, further comprising backlash removing means for removing play of the two sets of multi-start screws. 3. A valve timing for an internal combustion engine according to claim 1 or 2, further comprising a communication oil passage extending along an axis of the intermediate cylinder and opening at both end surfaces of the intermediate cylinder. Adjustment device.