JP2007239692A - Valve timing adjusting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve timing adjusting device having improved assembling work efficiency while reducing an individual difference in opening/closing timing between valves. <P>SOLUTION: The valve timing adjusting device 1 comprises a driven shaft for driving the opening/closing of at least one of an intake valve and an exhaust valve of an internal combustion engine, a housing member 5 to be rotated with one of the driven shaft and a driving shaft of the internal combustion engine, and a rotor member 3 coaxially stored in the housing member 5 so as to be rotated with the other (a cam shaft 2) of the driven shaft and the driving shaft in such a manner as rotational displacement relative to the housing member 5 in a predetermined angle range. The other (the cam shaft 2) of the driven shaft and the driving shaft and the housing member 5 have positioning parts (a positioning pin 22 and a positioning groove 57), respectively, which engage each other to restrict the range of relative rotational displacement between the driven shaft and the driving shaft. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a valve timing adjusting device that adjusts the opening / closing timing of at least one of an intake valve and an exhaust valve of an internal combustion engine for a vehicle or the like in accordance with an operation state.

  An intake valve for supplying an air-fuel mixture serving as a fuel to an internal combustion engine for vehicles or the like and an exhaust valve for discharging combustion gas are opened and closed according to the operation stroke of the internal combustion engine. In order to improve fuel consumption and suppress exhaust gas, valve timing adjusting devices that adjust the opening / closing timing of these valves in accordance with the operating conditions of the internal combustion engine have come to be attached. This device was originally applied to an intake valve, but recently, it is often applied to an exhaust valve. The valve timing adjusting device mainly includes a housing member and a rotor member that adjust timing by relative rotational displacement, one of which rotates with a cam and a camshaft that drive the valve to open and close, and the other is a drive for an internal combustion engine. Generally, it is configured to rotate together when driven from a shaft. Further, the relative rotational displacement, that is, phase adjustment between the housing member and the rotor member is often controlled by a hydraulic mechanism.

  The applicant of the present application discloses an example of this type of valve timing adjusting device in Patent Document 1. The device of Patent Document 1 includes a housing member, a vane rotor member, and a torsion coil spring, and the torsion coil spring is configured to urge the vane rotor member in a specific rotation direction with respect to the housing member. Further, according to the detailed description of the embodiment, the housing member is formed of a shoe housing and a sprocket portion, and the gear train on the outer peripheral side of the sprocket portion is driven from the crankshaft by a chain or the like. On the other hand, the vane rotor member is coaxially coupled with the camshaft inserted through the sprocket portion and rotates integrally. A positioning pin is provided at the tip of the camshaft, and a reference hole is provided in the vane rotor member so as to be assembled in phase with each other in the rotational direction. Furthermore, the vane provided in the vane rotor member is accommodated in the accommodation chamber in the shoe housing, and is configured to relatively rotate and displace in the accommodation chamber by hydraulic operation.

In the device of Patent Document 1, the rotational movement of the crankshaft is transmitted to the sprocket portion via a chain or the like, is transmitted to the camshaft via the shoe housing and the vane, the cam is driven, and the intake valve or the exhaust valve is operated. Open and close. At this time, the vane is relatively rotated and displaced in the housing of the shoe housing, so that the phase adjustment between the housing member and the vane rotor member is performed, and finally the phase adjustment between the crankshaft and the camshaft is performed. The opening / closing timing is adjusted.
JP 2005-325758 A

  By the way, in the apparatus of Patent Document 1, since many components are interposed in the transmission path from the crankshaft that is the drive shaft to the camshaft that is the driven shaft, there is a tolerance of component dimensions and an assembly dimension tolerance at the time of assembly. There was a large stacking tolerance due to the overlap. When assembling, the positioning pin at the tip of the camshaft is fastened with the reference hole of the vane rotor member fitted, but both are fastened from the viewpoint of dimensional accuracy restrictions and workability. It was necessary to provide clearance. Due to these causes, there has been a problem that an error occurs in the phase between the crankshaft and the camshaft and varies from product to product, and the valve opening / closing timing varies and affects the performance of the internal combustion engine. Further, when the positioning pin is fitted into the reference hole, since it cannot be visually confirmed, the operation is difficult, and it takes time and effort to assemble.

  The present invention has been made in view of the above-described background, and provides a valve timing adjusting device that reduces individual differences in valve opening / closing timing and improves assembly workability.

  A valve timing adjusting device according to the present invention includes a driven shaft that opens and closes at least one of an intake valve and an exhaust valve of an internal combustion engine, a housing member that rotates together with one of the driven shaft and the drive shaft of the internal combustion engine, and the housing A valve timing adjustment device comprising: a rotor member that is coaxially accommodated in a member, rotates with the other of the driven shaft and the drive shaft, and is rotatable relative to the housing member within a predetermined angular range, The driven shaft and the other of the drive shaft and the housing member each have a positioning portion that defines a range of relative rotational displacement between the driven shaft and the drive shaft by engaging with each other. .

  The present invention improves the accuracy of the product by reducing the number of intervening parts so that the phase alignment and assembling of the driven shaft and the drive shaft, which has been conventionally performed with a large number of parts intervening, can be performed. The main objective is to improve assembly workability and contribute to reducing manufacturing costs. In order to simplify the following description, it is assumed that the housing member that rotates with one of the driven shaft and the drive shaft rotates with the drive shaft. Then, the rotor member rotates with the other driven shaft.

  The housing member is a member that rotates together with the drive shaft, and may be directly connected to the drive shaft and directly driven, or may be indirectly driven via a transmission mechanism. The rotor member is a member that is accommodated coaxially in the housing member and rotates with the driven shaft, and is capable of relative rotational displacement with the housing member within a predetermined angle range. The angle or phase of the relative rotational displacement between the two can be controlled by, for example, a hydraulic mechanism. The driven shaft is generally called a camshaft and is provided with a cam for driving the valve. The driven shaft may be directly coupled to the rotor member or indirectly coupled. The two positioning portions are provided on the driven shaft and the housing member, respectively, and can be formed so as to define a range of relative rotational displacement by engaging with each other.

  In the valve timing adjusting device of the present invention configured as described above, the phase alignment between the drive shaft and the driven shaft at the time of assembly can be performed by engaging the two positioning portions. In other words, phase adjustment can be performed directly between the housing member that rotates with the drive shaft and the driven shaft. In contrast, conventionally, the rotor member is fixed to a specific phase with respect to the housing member, and the phase is adjusted between the rotor member and the driven shaft by the positioning pin and the reference hole. In other words, phase adjustment is performed indirectly between the housing member and the driven shaft with the rotor member interposed. Therefore, in the present invention, the number of parts to be interposed can be reduced, and the accuracy of phase alignment can be improved.

  Next, a specific structure of the positioning part will be described. One of the positioning portions of each of the driven shaft and the other of the drive shaft and the housing member is a positioning pin erected in the radial direction, and the remaining one is notched in the circumferential direction. It may be a positioning groove that is formed and into which the positioning pin is movably inserted. Further, it is preferable that a reference relative rotational displacement between the driven shaft and the drive shaft is defined when the positioning pin comes into contact with one end surface of the positioning groove.

  For example, one of the positioning portions can be a positioning pin standing radially outward on the outer periphery of the driven shaft, and the other can be a positioning groove formed by cutting the housing member in the circumferential direction. . And it can comprise so that a positioning pin can be inserted in a positioning groove | channel and it can move to the circumferential direction. Conversely, a positioning pin can be erected inward in the radial direction from the housing member, and a part of the driven shaft can be cut to form a circumferential positioning groove.

  At this time, a range of relative rotational displacement between the driven shaft and the drive shaft is defined within a range in which the positioning pin moves in the positioning groove. Further, since the rotational positional relationship is stabilized when the positioning pin comes into contact with one end surface of the positioning groove, it is preferable to set this as the reference state. That is, at the time of assembly, it is preferable that the positioning pin is brought into contact with the end surface, and the rotor member is coupled to the driven shaft in a state where the rotor member is arranged at the reference phase with respect to the housing member. During operation, the positioning pin moves in the positioning groove along with the relative rotational displacement of the rotor member. Therefore, it is preferable that the other end face of the positioning groove is wider than the displacement range of the rotor member so as not to obstruct the displacement of the rotor member.

  The housing member includes a housing main body portion that accommodates the rotor member, and a shaft support portion that supports the other of the driven shaft and the drive shaft, has the positioning portion, and rotates integrally with the housing main body portion. Or may consist of The shaft support portion may have a sprocket that is connected to the one of the driven shaft and the drive shaft via a transmission chain.

  The housing member may be formed by two parts of the housing main body part and the shaft support part in consideration of restrictions on parts production or convenience of assembling workability. Alternatively, a sprocket may be provided on the shaft support portion and connected via a drive shaft and a transmission chain, so that the drive shaft may be driven away from the driven shaft. In this aspect, conventionally, the phase is aligned with the driven shaft from the shaft support portion through the housing main body portion and the rotor member. In the present invention, direct phase alignment between the shaft support portion and the driven shaft can be performed, and the intervention of the two components can be omitted, and the effect of improving accuracy becomes remarkable.

  The rotor member and the driven shaft and the other of the drive shaft are continuously screwed to each other to provide a fastening bolt for coaxially coupling the rotor member and the other, and the fastening bolt and the rotor member The friction coefficient is larger than the friction coefficient between the rotor member and the other, and the fastening bolt is screwed in a state where the positioning pin is in contact with the one end surface of the positioning groove. Also good.

  A fastening bolt can be used as a member for coupling the rotor member and the driven shaft. Furthermore, by setting the magnitude relationship of the friction coefficient as described above, the fastening bolt is first firmly screwed together with the rotor member at the time of assembly and then rotates together, and then both are united so that the driven shaft is not loosened. Screwed onto. When the magnitude relationship of the friction coefficient is reversed, the rotor member and the driven shaft are screwed together while the fastening bolt and the rotor member are loosened, which may cause a phase error during operation. Regarding the friction coefficient, for example, the magnitude relation can be surely satisfied by managing the surface roughness of the wave contact surface or using a friction coefficient stabilizer. Furthermore, it is preferable that the rotor member is arranged at a reference phase with respect to the housing member so that the fastening bolt is screwed in a state where the positioning pin is in contact with one end surface of the positioning groove.

  According to the aspect using the fastening bolt as described above, the assembling work is performed by first inserting the positioning pin into the positioning groove having a wide phase adjustment range, then abutting on one end surface, and finally attaching the fastening bolt. The procedure of tightening may be performed. The operation of abutting the positioning pins is simple and can be performed in phase with ease, and visual confirmation is easy. On the other hand, in the conventional assembling work, it is difficult to visually check when the positioning pin is fitted into the reference hole, and it is difficult to manage the clearance, which is complicated and takes time. According to the present invention, the assembling accuracy can be improved, and the workability can be greatly improved so that the assembling work can be easily performed in a short time.

  In the valve timing adjusting device according to the present invention, the other of the driven shaft and the drive shaft and the housing member each have a positioning portion and are engaged with each other to define the range of relative rotational displacement. The number of parts that intervene during phase alignment with the drive shaft has been reduced, the assembly accuracy has been improved, and individual differences in valve opening and closing timing have been reduced.

  In addition, by using a positioning pin and a positioning groove as the positioning part and screwing the rotor member and the driven shaft with a fastening bolt, not only the assembly accuracy but also the assembly workability could be greatly improved. .

  The best mode for carrying out the present invention will be described with reference to FIGS. 1A and 1B are diagrams schematically illustrating a valve timing adjusting apparatus according to an embodiment of the present invention, in which FIG. 1A is a front view seen from an axial direction, and FIG. 1B is a side view partially showing a cross section. The valve timing adjusting apparatus 1 according to the embodiment adjusts the opening / closing timing of an intake valve of an internal combustion engine, and includes a camshaft 2, a rotor member 3, a fastening bolt 4, and a housing member 5.

  The camshaft 2 corresponds to a driven shaft and is a shaft member that extends to the left in FIG. 1B. A cam (not shown) is provided on the left to drive the intake valve to open and close. 2A and 2B are views showing the shape of the camshaft 2, wherein FIG. 2A is a front view seen from the axial direction, and FIG. 2B is a side view. A screw hole 21 is provided in the right axial center of the camshaft 2 in the drawing, and a positioning pin 22 is erected radially outward at a position slightly in the center from the right end.

  The rotor member 3 is a member that rotates together with the camshaft 2, and as shown in FIG. 1B, a cylindrical bushing vane 36 is press-fitted into the rotor vane 31 from the right side in the drawing. A through screw hole 32 is formed in the axial center of the rotor vane 31, and a fitting hole 33 into which the camshaft 2 is fitted is provided on the left side in the drawing. A vane is provided on the outer periphery of the rotor vane 31 so that the relative rotational displacement with respect to the housing member 5 can be adjusted within the phase adjustment range. A through hole 37 is provided in the axial center of the bushing vane 36.

  The fastening bolt 4 is a bolt composed of a head portion 41 and a screw portion 42. After passing through the through hole 37 of the bushing vane 36 from the right in the drawing, the through screw hole 32 of the rotor vane 31 and the screw of the camshaft 2 Screwed into the hole 21. In the assembled state of FIG. 1 (B), the camshaft 2 and the rotor member 3 are integrally coupled coaxially by the fastening bolts 4 and rotate integrally. The friction coefficient at the contact surface X between the fastening bolt 4 and the bushing vane 36 is set to be larger than the friction coefficient at the contact surface Y between the rotor vane 31 and the camshaft 2.

  The housing member 5 is a substantially cylindrical member that rotates together with a drive shaft (not shown), and is formed by connecting a housing body 51 and a shaft support 54 in the axial direction by three bolts 6. The housing main body 51 has an accommodating chamber therein, accommodates the vane so as to be capable of relative rotational displacement, and is configured to slide inside the bushing vane 36. The shaft support portion 54 has a sprocket 55 on the outer peripheral side, and is driven to rotate from a drive shaft via a transmission chain. A shaft support tube 56 is provided on the inner peripheral side of the shaft support portion 54 and rotatably supports the camshaft 2. A part of the shaft support tube 56 in the circumferential direction is notched to form a positioning groove 57. It should be noted that the angle range AL that is notched is larger than the phase adjustment range of the rotor vane 31.

  As shown in FIG. 1, the positioning pin 57 is arranged to engage with the positioning groove 57, and the positioning pin 22 can be relatively rotated and displaced within the angular range AL of the positioning groove 57. A lower end surface 58 of the positioning groove 57 in the figure is a reference surface, and assembly with the fastening bolt 4 is performed with the positioning pin 22 in contact with the end surface 58.

  Next, an assembling method, operation, and effect of the valve timing adjusting device 1 of the embodiment will be described. In the assembling work, the positioning pin 22 is brought into contact with the end surface 58, and the rotor vane 31 is arranged so as to be one end of the range of relative rotational displacement (phase adjustment range), and the fastening bolt 4 is tightened. That is, the phase alignment is performed directly between the shaft support portion 54 and the camshaft 2, and other members are not involved. After the assembly, the rotor vane 31 and the camshaft 2 are integrated, and can be displaced relative to the housing member 5 by rotation. At this time, the positioning pin 22 is also displaced counterclockwise in FIG. 1A. However, the positioning pin 22 does not contact the end surface 59 on the opposite side of the positioning groove 57 due to the restriction of the phase adjustment range of the rotor vane 31. Absent.

  Meanwhile, a conventional apparatus will be described with reference to FIG. 3A and 3B are diagrams for explaining a conventional valve timing adjusting device 9, wherein FIG. 3A is a side view for explaining a configuration and an assembling method, and FIG. 3B is a diagram for explaining positioning pin errors. In the conventional device 9, as shown in FIG. 3A, the positioning pin 92 is erected in the axial direction at the tip of the camshaft 2, and is fitted into a reference hole 94 provided in the rotor vane 31, so that the phase Was supposed to match. That is, the phase alignment is performed indirectly with the housing main body 51 and the rotor vane 31 interposed between the shaft support portion 54 and the camshaft 2.

  Therefore, according to this invention, the housing main-body part 51 and the rotor vane 31 which interpose at the time of phase alignment can be abbreviate | omitted, and the influence of component dimensional tolerance and assembly tolerance can be reduced.

  Further, regarding the assembly workability, in the apparatus 1 of the embodiment, when the positioning pin 22 is brought into contact with the end surface 58, it is only necessary to rotate the camshaft 2 which is not yet tightened, and visual confirmation can be performed. Is very good. However, it is difficult for the conventional apparatus 9 to visually check the fitting state of the positioning pins 92. Also. In order to manage the clearance, as shown in FIG. 3 (B), it is necessary to bring the positioning pin 92 close to the fixed direction in the reference hole 94. There is a possibility that it may occur, and the work itself is difficult and complicated. Therefore, the assembly workability has also been improved significantly.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which illustrates typically the valve timing adjustment apparatus of the Example of this invention, (A) is the front view seen from the axial direction, (B) is a side view which shows a cross section partially. It is a figure which shows the shape of the cam shaft in the Example of FIG. 1, (A) is the front view seen from the axial direction, (B) is a side view. It is a figure explaining the conventional valve timing adjustment apparatus, (A) is a side view explaining a structure and an assembling method, (B) is a figure explaining the error of a positioning pin.

Explanation of symbols

1: Valve timing adjusting device 2: Cam shaft (driven shaft) 21: Screw hole 22: Positioning pin 3: Rotor member 31: Rotor vane 36: Bushing vane 4: Fastening bolt 5: Housing member 51: Housing main body 54: Shaft support Part
57: Positioning groove 58: End surface 6: Bolt 9: Conventional valve timing adjusting device 92: Positioning pin 94: Reference hole AL: Angle range X, Y: Contact surface

Claims (6)

A driven shaft that opens and closes at least one of an intake valve and an exhaust valve of the internal combustion engine, a housing member that rotates together with one of the driven shaft and the drive shaft of the internal combustion engine, and is coaxially accommodated in the housing member A valve timing adjusting device comprising: a rotor member that rotates together with the other of the driven shaft and the drive shaft and is capable of relative rotational displacement in a predetermined angle range;
The other of the driven shaft and the drive shaft and the housing member each have a positioning portion that defines a range of relative rotational displacement between the driven shaft and the drive shaft by engaging with each other. Valve timing adjustment device.   One of the positioning portions of each of the driven shaft and the other of the drive shaft and the housing member is a positioning pin erected in the radial direction, and the remaining one is notched in the circumferential direction. The valve timing adjusting device according to claim 1, wherein the valve timing adjusting device is a positioning groove that is formed and into which the positioning pin is movably inserted.   3. The valve timing adjusting device according to claim 2, wherein a reference relative rotational displacement between the driven shaft and the drive shaft is defined when the positioning pin comes into contact with one end surface of the positioning groove.   The housing member includes a housing main body portion that accommodates the rotor member, and a shaft support portion that supports the other of the driven shaft and the drive shaft, has the positioning portion, and rotates integrally with the housing main body portion. The valve timing adjusting device according to claim 1, comprising:   The valve timing adjusting device according to claim 4, wherein the shaft support portion has a sprocket connected to the one of the driven shaft and the drive shaft via a transmission chain.   The rotor member and the driven shaft and the other of the drive shaft are continuously screwed to each other to provide a fastening bolt for coaxially coupling the rotor member and the other, and the fastening bolt and the rotor member The friction coefficient is larger than the friction coefficient between the rotor member and the other, and the fastening bolt is screwed in a state where the positioning pin is in contact with the one end surface of the positioning groove. The valve timing adjustment apparatus of -5.

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