JP2007040209A - Valve timing changing device for internal combustion engine and its fixing bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce/avoid abnormal noises resulting from the position of a meshing portion 48 by setting the axial dimension of the meshing portion 48 between screw portions 38, 40 without being restricted by a grooved portion 46 while using a fixing bolt 10 for simplifying the construction of an oil path. <P>SOLUTION: The rotating angle of a cam shaft 12 is delayed/advanced depending on hydraulic pressure supplied into a housing 14 via a pair of hydraulic pressure passages 18, 29. The fixing bolt 10 coaxially fixes the housing 14 to one end of a cam shaft 12. The screw portions 38, 40 meshing with each other are formed on the outer peripheral face of the fixing bolt 10 and on the inner peripheral face of a bolt fitting hole 36 of the cam shaft 12, respectively. On the outer peripheral face of the fixing bolt 10, the grooved portion 46 is provided extending to the axial direction. The grooved portion 46 forms part 18D of the hydraulic pressure passage 18 and at least part thereof is overlapped with the screw portion 38 in the axial direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a valve timing changing device for an internal combustion engine, and more particularly to a valve timing changing device for fixing a housing to one end of a camshaft with a fixing bolt.

Patent Document 1 describes an example of a valve timing changing device that can change the valve timing of an intake valve and an exhaust valve of an internal combustion engine. This device delays the rotation angle of the camshaft relative to the rotation angle of the crankshaft according to the hydraulic pressure supplied into the housing by a pair of hydraulic passages. The housing is coaxially connected to one end of the camshaft by a fixing bolt. It is fixed to. The fixing bolt is fitted into a bolt fitting hole that is recessed at one end of the camshaft through the bolt through hole of the housing, and the fixing bolt and the inner peripheral surface of the bolt fitting hole are mutually connected. A meshing screw portion is formed. One of the pair of hydraulic passages includes a bolt internal oil passage formed in an axial direction through the inside of the fixing bolt, and the other includes an outer peripheral surface of the fixing bolt and an inner peripheral surface of the bolt through hole / fitting hole. An annular oil passage formed between the two is included.
No. 7-44724

  In the valve timing changing mechanism as described above, the oil passage configuration on the camshaft side can be simplified by forming a part of the hydraulic passage by using the fixing bolt, the bolt through hole and the fitting hole. While it is possible to reduce the size of the shaft and improve the rigidity and strength, there is a problem that is uniquely found that unpleasant noise is generated under predetermined operating conditions, for example, during idle operation immediately after engine startup. As a result of the analysis by the present applicants, the abnormal noise is caused by the barrel of the camshaft that is rotatably supported on the cylinder head side by the axial force of the fixing bolt, although the journal portion closest to the bolt is slight. It was found that this was a so-called stick-slip sound that was generated when the surface pressure of this portion locally increased. The deformation of the journal part greatly depends on the position of the engagement part of the screw part, particularly the position of the end part on the housing side of the engagement part, and the closer this position is to the journal part, the more abnormal noise is caused by the deformation of the journal part. I found out that it tends to occur. However, in the configuration in which the annular oil passage is provided between the outer periphery of the fixing bolt and the bolt fitting hole of the camshaft as in Patent Document 1, it is necessary to dispose the meshing portion at an axial position away from the annular oil passage. Since the flexibility of the layout of the screw part and its meshing part is low, it is very difficult to arrange the end part on the housing side of the meshing part at the axial position away from the journal part as described above. .

  The present invention has been made in view of such problems, and provides a novel valve timing changing device for an internal combustion engine that can achieve both simplification of the oil passage configuration and reduction of noise, and a fixing bolt thereof. This is the main purpose.

  The valve timing changing device for an internal combustion engine according to the present invention delays the rotation angle of the camshaft relative to the rotation angle of the crankshaft in accordance with the hydraulic pressure supplied into the housing by the pair of hydraulic passages. The bolt has a fixing bolt that passes through a bolt through hole formed in the housing so as to fit into a bolt fitting hole formed at one end of the camshaft and coaxially fixes the housing to one end of the camshaft. Screw portions that mesh with each other are formed on the outer peripheral surface of the fixing bolt and the inner peripheral surface of the bolt fitting hole. A groove portion extending in the axial direction is recessed in at least one of the outer peripheral surface of the fixing bolt and the inner peripheral surface of the bolt fitting hole, and this groove portion forms a part of the hydraulic passage, and At least a portion overlaps the screw portion in the axial direction.

  According to the present invention, by providing a groove that forms a part of the hydraulic passage in the fixing bolt or the bolt fitting hole, the oil passage configuration on the camshaft side can be simplified, and the groove and the screw Is partially overlapped in the axial direction, so that the axial dimension of the screw portion can be set without being restricted by the groove portion. Generation of noise can be reduced and avoided, and both simplification of the oil passage configuration and reduction of abnormal noise can be achieved.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. 1 and 2 show a valve timing changing device according to a first embodiment of the present invention. Since the basic configuration of the valve timing changing device is known as described in the above-mentioned Japanese Utility Model Publication No. 7-44724, etc., only a brief description will be given here. The valve timing changing device includes a housing 14 that is a driven rotating body fixed to a front end of a camshaft 12 by a fixing bolt (cam bolt) 10 and a cam sprocket 16 that is a driving rotating body that is rotationally driven by a crankshaft via a chain. And have. A hydraulic actuator using a vane is built in the housing 14, and the hydraulic chamber in the housing 14 is passed through a pair of first hydraulic passages 18 (18A to 18F) and a second hydraulic passage 20 (20A to 20D). By changing the relative rotation angle between the cam sprocket 16 and the housing 14 in accordance with the hydraulic pressure supplied to the shafts 44 and 45, the rotation angle of the camshaft 12 relative to the rotation angle of the crankshaft is retarded, so Delay the valve timing of the valve. The hydraulic pressure supplied to the first and second hydraulic passages 18 and 20 is switched by a hydraulic control valve (not shown), and the operation of the hydraulic control valve is controlled by the engine control unit according to the engine operating conditions.

  The camshaft 12 is rotatably supported toward the cylinder head 24 by a plurality of journal portions including the first journal portion 22 on the most engine front side (left side in FIG. 1) Fr. The first journal portion 22 is rotatably supported by a bearing portion 27 formed on the cam bracket 26 and the cylinder head 24 that are fixed to the cylinder head 24. Further, the camshaft 12 is provided with a flange-like thrust bearing 28 projecting radially outward in order to prevent the camshaft 12 from moving in the axial direction immediately behind the first journal portion 22. .

  The fixing bolt 10 includes a head portion 30 and a shaft portion 32. The shaft portion 32 of the bolt 10 passes through a bolt through hole 34 formed through the housing 14 along the axis / axis direction 42 of the camshaft 12 and the housing 14, and is recessed at one end of the camshaft 12. By fitting in the bolt fitting hole 36, the housing 14 and the camshaft 12 are firmly fixed in a state where the housing 14 is sandwiched between the seating surface of the bolt head 30 and the front end surface of the camshaft 12. Fastened together. A male screw portion 38 that meshes with a female screw portion 40 formed on the inner peripheral surface of the bolt fitting hole 36 is formed on the outer peripheral surface on the tip end side of the bolt shaft portion 32.

  The cam sprocket 16 is disposed between the cylinder head 24 and the cam bracket 26 and the housing 14 in the axial direction, and the cam sprocket 16 projects from the front end surfaces of the cylinder head 24 and the cam bracket 26 toward the engine front Fr. It is rotatably supported on the outer periphery of the front end.

  The first hydraulic passage 18 is connected to one first hydraulic chamber 44 of the retard side / advance side hydraulic chamber defined in the housing 10 via the first to sixth partial oil passages 18A to 18F. The second hydraulic passage 20 is connected to the other second hydraulic chamber 45 of the retard side hydraulic chamber and the advance side hydraulic chamber via the seventh to tenth partial oil passages 20A to 20D. The first partial oil passage 18A and the seventh partial oil passage 20A are recessed in a port shape on the journal bearing surface 27 on the cam bracket 26 side. The second partial oil passage 18 </ b> B and the eighth partial oil passage 20 </ b> B are annular oil passages that are recessed over the entire circumference of the first journal portion 22 of the camshaft 12. It is connected to 18A and the seventh partial oil passage 20A. The third partial oil passage 18C is a radial oil passage that extends in the radial direction in the camshaft 12, and is connected to the second partial oil passage 18B at the radially outer end thereof. The fifth partial oil passage 18 </ b> E is an annular oil passage formed between the inner peripheral surface of the bolt through hole 34 and the outer peripheral surface of the bolt shaft portion 32. The fourth partial oil passage 18D is an axial oil passage extending in the axial direction 42 in the bolt fitting hole 36, and communicates the third partial oil passage 18C and the fifth partial oil passage 18E. A plurality of sixth partial oil passages 18F are formed in the housing 14, and the fifth partial oil passages 18E communicate with the first hydraulic chambers 44, respectively. A plurality (three in this embodiment) of tenth partial oil passages 20D formed in the housing 14 are disposed radially outward from the fifth partial oil passage (annular oil passage) 18E. Each is connected to the second hydraulic chamber 45. The plurality of ninth partial oil passages 20C extend along the axial direction 42 in the camshaft 12 and are arranged radially outward from the fourth partial oil passage 18D. The 10-part oil passage 20D is communicated. Reference numeral 50 denotes a pin hole into which the positioning pin is fitted.

  In this embodiment, a channel-shaped groove 46 extending in the axial direction 42 is recessed in the fixing bolt 10. Further, an auxiliary groove portion 47 extending in the circumferential direction is recessed in the outer peripheral surface of the fixing bolt 10 at an axial position facing the third partial oil passage 18C in the assembled state. The rear end of the groove 46 is connected.

  The fourth partial oil passage 18D is formed between the groove 46 including the auxiliary groove 47 and the inner peripheral surface of the bolt fitting hole 36 facing the groove 46. A part of the groove portion 46 overlaps and wraps in the axial direction with the male screw portion 38 (formation range), that is, in the axial direction with a meshing portion (range) 48 in which the male screw portion 38 and the female screw portion 40 mesh. Duplicate. That is, the groove portion 46 extends in the axial direction so as to reach the male screw portion 38. Accordingly, the end portion 49 on the housing 14 side of the meshing portion 48 is set at a position that is closer to the housing 14 than the bearing portion 27 and the first journal portion 22 that is rotatably supported by the bearing portion 27, and more specifically, Further, it is set in the vicinity of the front end of the camshaft 12, further forward of the engine Fr than the front end surfaces of the cylinder head 24 and the cam bracket 26.

  As described above, in this embodiment, since the hydraulic passages 18 and 20 are partially formed by using the fixing bolt 10 and the bolt through holes 34 and the fitting holes 36, they are formed in the camshaft 12. The oil passage configuration can be simplified, and the camshaft 12 can be reduced in size, strength and rigidity. And since the groove part 46 which forms part 18D of the 1st hydraulic path 18 is partially overlapped with the external thread part 38 in the axial direction, the freedom degree of the layout of a hydraulic path and a thread part improves. Specifically, the axial dimension of the male screw portion 38 can be set without being restricted by the groove portion 46. For this reason, the engagement portion 48 of the screw portions 38 and 40 is disposed closer to the housing 14 so as to shorten the fixing bolt 10 and the camshaft 12, and the abnormal noise caused by the axial position of the engagement portion 48 described above. Generation can be reduced or avoided. Thus, simplification of the oil passage configuration and reduction of noise can be achieved at a high level.

  3 and 4 show a valve timing changing apparatus according to a second embodiment of the present invention. Note that the same reference numerals are assigned to the same components as those in the first embodiment, and redundant description will be omitted as appropriate.

  In the second embodiment, a channel-shaped groove 46A extending in the axial direction is recessed in the inner peripheral surface of the bolt fitting hole 36 of the camshaft 12. The fourth partial oil passage 18D is formed between the groove 46A and the outer peripheral surface of the fixing bolt 10 facing the groove 46A. A part of the groove portion 46A overlaps with the female screw portion 40, that is, overlaps with a meshing portion 48 in which the male screw portion 38 and the female screw portion 40 mesh with each other in the axial direction. That is, the groove portion 46 </ b> A extends in the axial direction so as to reach the female screw portion 40. Accordingly, the end portion 49 of the meshing portion 48 on the housing 14 side is disposed closer to the housing 14 than the bearing portion 27 and the first journal portion 22 rotatably supported by the bearing portion 27, and more specifically, the cylinder head 24. In addition, it is set near the front end of the camshaft 12 in front of the engine further than the front end surface of the cam bracket 26.

  According to the second embodiment, as in the first embodiment, in addition to being able to achieve both simplification of the oil passage configuration and reduction of abnormal noise, the fixing bolt 10 can be compared with the first embodiment. Since it is not necessary to form a groove, the manufacture thereof is easy, and the strength and rigidity of the bolt can be easily ensured.

  The characteristic technical idea of the present invention that can be understood from the above description will be described with reference to the above-described embodiment. However, the present invention is not limited to the configuration of the embodiment given the reference numerals, and includes various modifications and changes without departing from the spirit thereof. For example, a plurality of grooves may be provided. Moreover, you may make it provide a groove part in both the outer peripheral surface of a fixed volt | bolt, and the internal peripheral surface of a bolt fitting hole.

  (1) In a valve timing changing device for an internal combustion engine that delays the rotation angle of the camshaft 12 with respect to the rotation angle of the crankshaft according to the hydraulic pressure supplied into the housing 14 by the pair of hydraulic passages 18 and 20, the housing 14 A fixing bolt 10 that passes through a bolt through hole 34 formed in the cam shaft 12 and fits into a bolt fitting hole 36 formed at one end of the camshaft 12, and fixes the housing 14 coaxially to one end of the camshaft 12. Have On the outer peripheral surface of the fixing bolt 10 and the inner peripheral surface of the bolt fitting hole 36, threaded portions 38 and 40 that mesh with each other are formed. A groove 46 (46A) extending in the axial direction is provided in at least one of the outer peripheral surface of the fixing bolt 10 and the inner peripheral surface of the bolt fitting hole 36. The groove 46 (46A) forms a part 18D of the hydraulic passage, and at least a part thereof overlaps the screw parts 38 and 40 in the axial direction.

  Since the groove 46 (46A) that forms a part 18D of the hydraulic passage is recessed in the fixing bolt 10 and the bolt fitting hole 36, the oil passage configuration on the camshaft 12 side can be simplified. The camshaft 12 can be reduced in size, strength and rigidity, and the groove 46 is partially overlapped with the screw portions 38 and 40 in the axial direction, so that the degree of freedom in layout is improved. Specifically, the axial dimensions of the screw portions 38 and 40 can be set without being restricted by the groove portion 46. For this reason, by arranging the meshing portion 48 of the screw portions 38 and 40 closer to the housing 14, it is possible to reduce / avoid the above-described abnormal noise caused by the position of the meshing portion 48. Thus, simplification of the oil passage configuration and reduction of noise can be achieved at a high level.

  (2) The camshaft 12 is rotatably supported by the bearing portion 27 on the cylinder head 24 side by a plurality of journal portions, and the end portion 49 on the housing 14 side of the meshing portion 48 of the screw portions 38 and 40 is the most housing. It is located closer to the housing 14 than the journal portion 22 on the 14 side. For this reason, even if the camshaft 12 is deformed into a barrel shape at the meshing portion 48 due to the bolt axial force at the time of assembly, it is possible to effectively reduce / avoid the generation of abnormal noise due to this deformation, so-called stick-slip noise. it can.

  (3) Preferably, one first hydraulic passage 18 has a first section (fifth partial oil passage) 18E formed between the inner periphery of the bolt through hole 34 and the outer periphery of the fixing bolt 10. A second section (third partial oil passage) 18C extending in the radial direction in the camshaft 12 is formed between the groove 46 (46A) and its opposing surface, and the first section 18E and the second section are formed. And a third section (fourth partial oil passage) 18D that communicates with the section 18C, and has a simple oil passage configuration that also uses the bolt through hole 34.

  (4) More preferably, the other second hydraulic passage 20 is formed in the housing 14, and is a fourth section (tenth partial oil path) disposed radially outward from the first section 18E. 20D and the fifth section (the ninth partial oil passage) which is connected to the fourth section 20D, is formed on the camshaft 12, and is arranged radially outward from the third section 18D. ) 20C. According to such an oil passage configuration, there is no need to form an oil passage extending in the axial direction inside the bolt as in the above-mentioned Japanese Utility Model Publication No. 7-77424, so that the bolt can be simplified and improved in strength and rigidity. Can be planned. That is, the present invention is particularly effective for a valve timing control device including such hydraulic passages 18 and 20.

1 is a cross-sectional view showing a valve timing changing device for an internal combustion engine according to a first embodiment of the present invention. Sectional drawing in alignment with the AA of FIG. Sectional drawing which shows the valve timing change apparatus of the internal combustion engine which concerns on 2nd Example of this invention. Sectional drawing which follows the BB line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Fixing bolt 12 ... Camshaft 14 ... Housing 18 ... 1st hydraulic path 18C ... 3rd partial oil path (2nd area)
18D ... Fourth partial oil passage (third section)
18E ... Fifth partial oil passage (first section)
20 ... Second hydraulic passage 20C ... Ninth partial oil passage (fifth section)
20D ... 10th partial oil passage (fourth section)
DESCRIPTION OF SYMBOLS 22 ... 1st journal part 24 ... Cylinder head 26 ... Cam bracket 27 ... Bearing part 34 ... Bolt through-hole 36 ... Bolt fitting hole 38 ... Male screw part 40 ... Female screw part 46, 46A ... Groove part 48 ... Meshing part

Claims (5)

In the internal combustion engine valve timing changing device for delaying the rotation angle of the camshaft relative to the rotation angle of the crankshaft according to the hydraulic pressure supplied into the housing by the pair of hydraulic passages,
A bolt that penetrates the bolt through hole formed in the housing and fits into a bolt fitting hole formed at one end of the camshaft, and has a fixing bolt that coaxially fixes the housing to one end of the camshaft;
The outer peripheral surface of the fixing bolt and the inner peripheral surface of the bolt fitting hole are formed with threaded portions that mesh with each other.
And, at least one of the outer peripheral surface of the fixing bolt and the inner peripheral surface of the bolt fitting hole has a groove extending in the axial direction, and this groove forms a part of the hydraulic passage, And the valve timing change apparatus of the internal combustion engine characterized by at least one part overlapping with the said thread part in an axial direction. The camshaft is rotatably supported by a bearing portion on the cylinder head side by a plurality of journal portions,
2. The valve timing changing device for an internal combustion engine according to claim 1, wherein an end portion on the housing side of the meshing portion of the screw portion is located closer to the housing than the journal portion on the most housing side.   One of the pair of hydraulic passages includes a first section formed between an inner periphery of the bolt through hole and an outer periphery of the fixing bolt, a second section extending radially in the camshaft, and the groove portion. The internal combustion engine valve according to claim 1, further comprising: a third section that is formed between the first section and the opposite face and communicates the first section and the second section. Timing change device.   The other of the pair of hydraulic passages is formed in the housing and is connected to the fourth section, which is disposed radially outward from the first section, and to the fourth section. The valve timing changing device for an internal combustion engine according to claim 3, further comprising a fifth section that is formed and is arranged radially outward from the third section. Bolt penetration formed in the housing and applied to the valve timing changing device of the internal combustion engine for delaying the rotation angle of the camshaft relative to the rotation angle of the crankshaft according to the hydraulic pressure supplied into the housing by a pair of hydraulic passages In the fixing bolt that penetrates the hole and fits into a bolt fitting hole formed at one end of the camshaft, and coaxially fixes the housing to one end of the camshaft,
On the outer peripheral surface of the fixing bolt, a male screw portion that meshes with a female screw portion formed on the inner peripheral surface of the bolt fitting hole is formed, and a groove portion that extends in the axial direction is formed.
The groove portion forms a part of the hydraulic passage, and at least a portion thereof overlaps with the male screw portion in the axial direction.

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