Valve timing control device for internal combustion engine

Abstract

Provided is a valve timing control device for an internal combustion engine, wherein the rigidity of a rotor is improved, and the degree of freedom of layout of radial oil passages is improved. A vane rotor (9) is provided with: a rotor (13) fixed to a camshaft (2) by means of a cam bolt (8); the four blades divide the action chamber in the shell into four lag angle oil pressure chambers and advance angle oil pressure chambers respectively; a second axial oil hole (21) formed inside the rotor in the direction of the rotational axis and communicating with a camshaft oil passage (19); the second radial oil path (23) is respectively communicated with the second axial oil hole and the four advance angle oil pressure chambers; the inner diameter (d) of the axial oil hole (21) is formed larger than the inner diameter (d1) of the camshaft oil passage, and the axial center position (P) of the axial oil hole (21) is disposed so as to be offset radially outward from the axial center position (P1) of the camshaft oil passage.

Description

Technical Field

[0001] The invention relates to a valve timing control device for an internal combustion engine. Background Art

[0002] The conventional valve timing control device described in the following patent document 1 comprises: a timing sprocket that transmits rotational force from a crankshaft; a cylindrical housing that is coupled to the timing sprocket; a vane rotor that is relatively rotatably disposed inside the housing; two retardation angle oil pressure chambers and an advance angle oil pressure chamber that are separated by the vane rotor into action chambers inside the housing; and a hydraulic circuit that controls the supply and discharge of control oil pressure from an oil pump to the retardation angle oil pressure chamber and the advance angle oil pressure chamber. The vane rotor is fixed to one end of the camshaft in the direction of the rotation axis by a cam bolt.

[0003] The oil pressure circuit comprises: a plurality of camshaft oil circuits for retardation and advancement, which are formed axially inside one end of the camshaft; a plurality of axial holes for retardation and advancement, which are formed along the internal axial direction of the vane rotor, and one end is connected to each of the camshaft oil circuits; a pair of retardation side oil circuits, which are bent into an L-shape inside the rotor, each having one end connected to the axial hole on the retardation side, and the other end connected to the two retardation oil pressure chambers; a pair of advance angle side oil circuits, which are formed radially inside the rotor, one end connected to the axial hole on the advance angle side, and the other end connected to the two advance angle oil pressure chambers.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: (Japan) Patent Publication No. 2019-194442 Summary of the invention

[0007] Technical problem to be solved by the invention

[0008] As described above, in the above-mentioned existing valve timing control device, the oil circuit on the retard angle side is bent into an L-shape inside the rotor, and the oil circuit on the advance angle side is formed into a straight line along the radial direction inside the rotor, but the inner diameter of the multiple axial holes of the rotor is formed to be the same size as the inner diameter of the camshaft oil circuit and the inner diameters of the retard angle side and advance angle side oil circuits and is fixed.

[0009] Therefore, the freedom of layout of each oil hole and each oil circuit is restricted. In particular, the layout of the retard angle side oil circuit and the advance angle side oil circuit cannot be freely changed due to the different structures of the valve timing control device and the different outer diameters of the cam bolt.

[0010] One object of the present invention is to provide a valve timing control device for an internal combustion engine, which can achieve freedom in the layout of the radial oil circuit by enlarging the inner diameter of the axial oil hole formed inside the rotor and offsetting the configuration radially outward of the rotor relative to the camshaft oil circuit.

[0011] Technical solutions to solve problems

[0012] As a preferred embodiment of the present invention, it is characterized by comprising: a housing to which the rotational force from the crankshaft is transmitted and which has an operating chamber inside; and a vane rotor which is relatively rotatably arranged inside the housing.

[0013] The vane rotor comprises: a rotor fixed to a camshaft by cam bolts; a plurality of vanes arranged on the rotor to divide the action chamber into a plurality of first oil pressure chambers and a second oil pressure chamber; a plurality of axial oil holes formed inside the rotor along the direction of the rotation axis of the rotor, respectively connected to a plurality of camshaft oil passages formed on the camshaft, the inner diameter of the axial oil hole being formed to be larger than the inner diameter of the camshaft oil passage, and the center position of the axial oil hole being offset radially outward relative to the camshaft oil passage; a first radial oil passage, respectively connected to the axial oil holes, one straight end opening to one of the first oil pressure chambers, and the other bent end opening to another of the first oil pressure chambers.

[0014] Effects of the Invention

[0015] According to the preferred aspect of the present invention, it is possible to ensure an appropriate communication state between the axial oil hole in the rotor and the camshaft oil passage, and to improve the degree of freedom in the layout of the first radial oil passage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a longitudinal sectional view showing an embodiment of a hydraulic circuit including a valve timing control device according to the present invention.

[0017] Figure 2 It indicates the state where the vane rotor of the valve timing control device rotates relatively to the most retarded angle position. Figure 1 A-A line cross-sectional view.

[0018] Figure 3 It indicates that the blade rotor has rotated relatively to the most advanced angle position. Figure 1 BB line cross-sectional view.

[0019] Figure 4 It is a partial cross-sectional view showing the relationship between the second camshaft oil passage, the second axial oil hole, and the second radial oil passage in the present embodiment.

[0020] Figure 51 is a schematic diagram showing a connection state between the second camshaft oil passage, the second axial oil hole, and the second radial oil passage on the advance angle side in the present embodiment.

[0021] Figure 6 It means from Figure 5 The diagram shows the flow characteristics of oil flowing from the second camshaft oil passage into the second axial oil hole and the second radial oil passage.

[0022] Description of Reference Numerals

[0023] 1: timing sprocket; 2: camshaft; 2a: one end; 2c, 2d: first and second oil holes; 3: phase change mechanism; 4: hydraulic circuit; 6: housing; 8: cam bolt; 8a: head; 8b: shaft; 8c: external thread; 9: vane rotor; 10: front plate; 11a~11d: sliding shoe; 15a~15d: retardation angle oil pressure chamber; 16a~16d: advance angle oil pressure chamber; 13: rotor; 13a: bolt insertion hole; 14a~14d: vane; 15a~15d: retardation angle oil pressure chamber (first oil pressure chamber); 16a~16d: advance angle oil pressure chamber Chamber (second oil pressure chamber); 18: first camshaft oil circuit; 18a: one end; 18b: the other end; 19: second camshaft oil circuit; 19a: one end; 19b: the other end; 20: first axial oil hole; 21: second axial oil hole; 22: first radial oil circuit; 22a: long dimension path (one end); 22b: short dimension path (the other end); 23: second radial oil circuit; 23a: long dimension path (one end); 23b: short dimension path (the other end); 25: lag angle oil passage; 26: advance angle oil passage; 27: oil pump; 28: solenoid switching valve. DETAILED DESCRIPTION

[0024] Hereinafter, an embodiment of applying the valve timing control device of an internal combustion engine of the present invention to the exhaust valve side will be described based on the drawings. It should be noted that the internal combustion engine is, for example, an inline 4-cylinder engine, and has two intake valves and two exhaust valves provided in each cylinder.

[0025] Figure 1 is a longitudinal sectional view showing an embodiment of a hydraulic circuit including a valve timing control device of the present invention, Figure 2 The valve timing control device is in a state where the vane rotor is relatively rotated to the most retarded angle side. Figure 1 A-A line section view, Figure 3 This indicates that the vane rotor is relatively rotated to the most advanced angle side position. Figure 1 BB line cross-sectional view.

[0026] like Figures 1 to 3As shown, the valve timing control device includes: a timing sprocket (hereinafter referred to as a sprocket) 1, which is driven to rotate by the crankshaft of the internal combustion engine via a timing chain; a camshaft 2 on the intake side, which is arranged to be relatively rotatable relative to the sprocket 1; a phase change mechanism 3, which is arranged between the sprocket 1 and the camshaft 2 and changes the relative rotation phase of the sprocket 1 and the camshaft 2; and a hydraulic circuit 4, which activates the phase change mechanism 3.

[0027] The sprocket 1 is formed into a thick-walled disk shape by compressing and heating iron-based metal powder to form a sintered metal, and has a gear portion 1a around which a timing chain is wound on the outer periphery. In addition, the sprocket 1 has a support hole 1b formed in the center through which one end 2a of the camshaft 2 in the direction of the rotation axis can be rotatably inserted.

[0028] The sprocket 1 has four internal threaded holes formed at circumferentially evenly spaced positions on the outer periphery thereof for screwing four bolts (not shown). Figure 2 As shown, the sprocket 1 has a pin 1c protruding from a predetermined position on the inner surface opposite to the camshaft 2 in the rotation axis direction for positioning with the housing body 7 described later. The sprocket 1 is configured as a rear cover that closes the other end (rear end) opening of the housing body 7 described later.

[0029] The camshaft 2 is rotatably supported at the upper end of the cylinder head 01 via a plurality of cam carriers 02 , and a plurality of egg-shaped cams (not shown) for opening and closing the intake valves and the exhaust valves are integrally fixed to the outer circumference at predetermined positions in the axial direction.

[0030] In addition, if Figure 1 As shown, the camshaft 2 has a bolt insertion hole 2b formed inside one end 2a along the rotation axis direction. The bolt insertion hole 2b has an internal threaded hole for screwing into the external threaded portion 8c of the cam bolt 8 described later. In addition, the camshaft 2 has a first oil hole 2c on the retard angle side and a second oil hole 2d on the advance angle side radially relative to the rotation axis at one end 2a. The first oil hole 2c and the second oil hole 2d are arranged at a predetermined interval in the rotation axis direction of the camshaft 2. In addition, as Figure 1~Figure 3 As shown, two first camshaft oil passages 18, 18 on the retard angle side and two second camshaft oil passages 19, 19 on the advance angle side are provided in parallel in the axial direction inside one end portion 2a of the camshaft 2.

[0031] like Figure 2 As shown, the two first camshaft oil passages 18, 18 are arranged at symmetrical positions with the bolt insertion hole 2b as the central axis, and each end 18a, 18a opens to the first oil hole 2c, and each other end 18b, 18b opens to a pair of first axial oil holes 20, 20 on the lag angle side described later. Figure 3As shown, the two second camshaft oil passages 19, 19 are also provided at symmetrical positions with the bolt insertion hole 2b as the central axis, and each one end 19a, 19a opens to the second oil hole 2d, and each other end 19b, 19b opens to a pair of second axial oil holes 21, 22 on the advance angle side described later. In addition, the first and second oil holes 2c, 2d and the first and second camshaft oil passages 18, 19 constitute a part of the hydraulic circuit 4.

[0032] like Figures 1 to 3 As shown, the phase change mechanism 3 comprises: a housing 6, which is combined with the sprocket 1 and has an operating chamber inside; a vane rotor 9, which is relatively rotatably accommodated in the housing 6 and is fixed to one end 2a of the camshaft 2 from the rotating axis direction via a cam bolt 8; retard angle oil pressure chambers 15a, 15b, 15c, 15d as the first oil pressure chambers and advance angle oil pressure chambers 16a, 16b, 16c, 16d as the second oil pressure chambers, which divide the operating chambers of the housing 6 into multiple (four in this embodiment) by the vane rotor 9.

[0033] The housing 6 comprises: a housing body 7 formed of sintered metal into a cylindrical shape similarly to the sprocket 1; a front plate 10 formed by stamping to close the front end opening of the housing body 7; and the sprocket 1 as a rear cover to close the rear end opening.

[0034] The housing body 7 is provided with a plurality of (four in this embodiment) first to fourth sliding shoes 11a, 11b, 11c, 11d at substantially equal intervals in the circumferential direction on the inner circumferential surface. Bolt insertion holes 12a to 12d are formed in the interior of each of the sliding shoes 11a to 11d along the rotation axis direction of the housing body 7.

[0035] The first to fourth shoes 11 a to 11 d protrude from the inner peripheral surface of the case body 7 in the rotation axis direction, and are each formed in a substantially trapezoidal shape in side view.

[0036] The case body 7 has a lightening groove 7a formed at a position corresponding to the first shoe 11a on the outer peripheral surface thereof. The lightening groove 7a is used for positioning the case body 7 with the sprocket 1 and the front plate 10 in order to reduce the weight of the case body 7 and balance the overall weight.

[0037] Furthermore, the case body 7 is provided with a pin hole 7 b in which a pin 1 c used for positioning with the sprocket 1 is fitted, on the outer surface of the first shoe 11 a on the sprocket 1 side.

[0038] like Figure 1As shown in FIG. 1 , the cam bolt 8 is composed of a head 8a on the front plate 10 side, a shaft 8b extending from the head 8a to the cam shaft 2 side, and an external threaded portion 8c formed on the front end side of the shaft 8b and screwed into the internal threaded hole 2c of the cam shaft 2. In addition, the head 8a of the cam bolt 8 has a flange portion 8d for seating integrally with the root of the shaft 8b. The shaft 8b of the cam bolt 8 is formed to have a larger outer diameter than the shaft of the cam bolt in the prior art described in the above-mentioned publication. When tightened, the seating surface of the flange portion 8d on the shaft 8b side is seated on the hole edge of the bolt insertion hole 13a of the vane rotor 9 described later.

[0039] The front plate 10 is formed into a disc shape by, for example, stamping an iron-based metal plate. The front plate 10 has a large diameter through hole 10a formed in the center and four bolt insertion holes (not shown) formed at substantially equal intervals in the circumferential direction of the outer periphery for inserting four bolts 5 .

[0040] The housing body 7 , the front plate 10 and the sprocket 1 are fastened together by four bolts 5 .

[0041] The blade rotor 9 is formed integrally by, for example, compressing and sintering metal powder. Figure 1~Figure 3 As shown, the vane rotor 9 comprises: a rotor 13, which is directly fixed to one end portion 2a of the camshaft 2 by a cam bolt 8; a plurality of (four in the present embodiment) first to fourth vanes 14a to 14d, which are integrally provided on the outer peripheral surface of the rotor 13 and extend radially at positions equally spaced at approximately 90° in the circumferential direction.

[0042] The rotor 13 has a bolt insertion hole 13a formed at a central position in the direction of the rotation axis through which the shaft portion 8b of the cam bolt 8 is inserted, and a circular fitting groove 13b is formed at the center of the rear end surface on the sprocket 1 side, into which the front end portion of the one end portion 2a of the cam shaft 2 is fitted. In addition, the rotor 13 has a cylindrical portion 13c on the front end surface on the front plate 10 side that is inserted into the above-mentioned insertion hole 10a and protrudes forward. In addition, as shown in FIG. Figure 1 As shown in FIG. 1 , a disc spring 36 for urging the vane rotor 9 in the rotation direction toward the advanced angle side is provided between the front plate 10 and the cylindrical portion 13 c.

[0043] like Figure 2 and Figure 3 As shown in FIG. 1 , the first to fourth vanes 14a to 14d are integrally provided on the outer periphery of the rotor 13 and are disposed between the slide shoes 11a to 11d. The vanes 14a to 14d divide the operating chamber in the housing 6 into four retarded angle oil pressure chambers 15a to 15d as first oil pressure chambers and four advanced angle oil pressure chambers 16a to 16d as second oil pressure chambers by the relative relationship with the slide shoes 11a to 11d.

[0044] Furthermore, one first blade 14a of the four blades 14a to 14d is formed wide in the circumferential direction, but the other three second to fourth blades 14b to 14d are formed thin and have substantially the same circumferential width. Thus, the weight of the entire blade rotor 9 is balanced.

[0045] In addition, sealing members 17a that slide and seal on the inner peripheral surface of the housing body 7 are respectively fitted and fixed in the sealing grooves formed on the outer surfaces of the respective front end portions of the respective blades 14a to 14d. On the other hand, sealing members 17b that slide and seal on the outer peripheral surface of the rotor 13 are respectively fitted and fixed in the sealing grooves formed on the inner peripheral surfaces of the front ends of the respective sliding shoes 11a to 11d.

[0046] like Figure 2 As shown in FIG. 1 , when the vane rotor 9 rotates relatively in the counterclockwise direction in the figure, the side surface 14e of the first vane 14a contacts the opposite side surface of the fourth shoe 11d to limit the rotation position on the maximum lag angle side. Figure 3 As shown in FIG. 1 , when the vane rotor 9 rotates relatively clockwise in the figure, the other side surface 14f of the first vane 14a contacts the opposite side surface of the first shoe 11a to limit the rotation position on the most advanced angle side. In addition, the first vane 14a and the first and fourth shoes 11a and 11d function as mechanical stoppers that limit the most retarded angle position and the most advanced angle position of the vane rotor 9.

[0047] At this time, the two side surfaces of the other three second to fourth vanes 14b to 14d are not in contact with the opposite side surfaces of the respective slide shoes 11a to 11d which are opposite in the circumferential direction, but are in a separated state. Therefore, the contact accuracy of the first vane 14a with the first and fourth slide shoes 11a and 11d is improved, and the supply speed of the oil pressure to the respective retard angle oil pressure chambers 15a to 15d and the respective advance angle oil pressure chambers 16a to 16d is increased, and the forward and reverse rotation responsiveness of the vane rotor 9 is improved.

[0048] Moreover, if Figures 1 to 3 As shown, the rotor 13 has two first axial oil holes 20, 20 on the retard angle side and second axial oil holes 21, 22 on the advance angle side formed linearly in the rotation axis direction of the rotor 13. In addition, the rotor 13 has first radial oil passages 22, 22 connecting the first axial oil holes 20, 20 with the respective retard angle oil pressure chambers 15a to 15d, and second radial oil passages 23, 23 connecting the second axial oil holes 21, 21 with the respective advance angle oil pressure chambers 16a to 16d formed therein.

[0049] The two first axial oil holes 20, 20 are provided at symmetrical positions with respect to the bolt insertion hole 13a of the cam bolt 8 as the center, and each one end portion is communicated with the other end portion 18b of the first camshaft oil passage 18, and each other end portion is communicated with each first radial oil passage 22, 22. The two second axial oil holes 21, 21 are also provided at symmetrical positions with respect to the bolt insertion hole 13a as the center, and each one end portion is communicated with the other end portion 19b of the second camshaft oil passage 19, and each other end portion is communicated with each second radial oil passage 23, 23.

[0050] In addition, if Figure 2 and Figure 3 As shown, each of the first radial oil passages 22, 22 and each of the second radial oil passages 23, 23 are bent into an L shape, and each of the outer ends of the long passages 22a, 22a and the short passages 22b, 22b of the first radial oil passages 22, 22 is communicated with the four retarded angle oil pressure chambers 15a to 15d, and the vicinity of the junction of the long passages 22a, 22a and the short passages 22b, 22b is communicated with the first axial oil holes 20, 20. The second radial oil passages 23, 23 are also each of the outer ends of the long passages 23a, 23a and the short passages 23b, 23b is communicated with the four advanced angle oil pressure chambers 16a to 16d, and the vicinity of the junction of the long passages 23a, 23a and the short passages 23b, 23b is communicated with the second axial oil holes 21, 21.

[0051] Figure 4 is a partial cross-sectional view showing the relationship between the second camshaft oil passage, the second axial oil hole, and the second radial oil passage in this embodiment, Figure 5 Schematic diagram showing the connection between the second camshaft oil passage, the second axial oil hole, and the second radial oil passage on the advance angle side in this embodiment. Figure 4 and Figure 5 The relationship between the second camshaft oil passage and the second axial oil hole and the second radial oil passage is described, but since the relationship between the first camshaft oil passage and the first axial oil hole and the first radial oil passage is the same, the first and second axial oil holes 20-21 described as the relationship between the first camshaft oil passage and the first axial oil hole and the first radial oil passage are as follows: Figure 1 and Figure 4 , Figure 5 As shown, the inner diameters d of the first and second axial oil holes 20-21 are the same and are formed uniformly in the axial direction. In addition, the inner diameters d of the first and second axial oil holes 20-21 are formed larger than the inner diameters d1 of the first and second camshaft oil passages 18-19, and are formed larger than the inner diameters d2 of the first and second radial oil passages 22-23. In addition, the inner diameters d2 of the first and second radial oil passages 22-23 are formed larger than the inner diameters d1 of the first and second camshaft oil passages 18-19.

[0052] like Figure 4As shown, the axial center positions P of the first and second axial oil holes 20~21 are offset toward the radial outside of the rotor 13 relative to the axial center positions P1 of the first and second camshaft oil passages 18~19, and the parts 21a, 21a on the side of the bolt insertion hole 13a in the inner circumferential surface of the first and second axial oil holes 20~21 are in a state of roughly overlapping (inscribed in) with the corresponding parts of the inner circumferential surface of each camshaft oil passage 18~19.

[0053] Furthermore, the axial center positions P2 of the long passages 22 a and 23 a of the first and second radial oil passages 22 and 23 are slightly offset radially outward from the axial center positions P of the first and second axial oil holes 21 and 21 .

[0054] like Figures 1 to 3 As shown, the hydraulic circuit 4 selectively supplies or discharges hydraulic oil (hydraulic pressure) to or from the respective retard angle and advance angle hydraulic chambers 15 a to 15 d and 16 a to 16 d via the first radial oil passages 22 and the second radial oil passages 23 and 23 .

[0055] That is, the hydraulic circuit 4 has the above-mentioned first and second radial oil passages 22-23, the first and second axial oil holes 21-22 and the first and second camshaft oil passages 18-19, and the retarded angle oil passage 25 and the advanced angle oil passage 26 connected to the first and second camshaft oil passages 18-19 via the first and second oil holes 2c and 2d. In addition, the hydraulic circuit 4 has: an oil pump 27 as a fluid pressure supply source, which selectively supplies working oil to each of the retarded angle and advanced angle oil passages 25 and 26; and an electromagnetic switching valve 28, which switches the flow passages for supply and discharge relative to the retarded angle oil passage 25 and the advanced angle oil passage 26 according to the operating state of the internal combustion engine.

[0056] The oil pump 27 is a general oil pump such as a trochoid pump that is driven to rotate by the crankshaft of the internal combustion engine. The oil pump 27 supplies the lubricating oil sucked from the suction passage 27b to the main oil gallery (M / G) and the electromagnetic switching valve 28 from the discharge passage 27b via the filter 29. In addition, a relief valve 30 is provided on the downstream side of the discharge passage 27b to prevent the discharge pressure from becoming too high.

[0057] The electromagnetic switching valve 28 is a two-position three-way proportional valve, and the other ends of the retard angle oil passage 25 and the advance angle oil passage 26 are connected to two supply and discharge ports formed in the valve body (not shown). In addition, the electromagnetic switching valve 28 moves the spool valve body provided in the valve body to slide freely in the axial direction in the valve body in the front-rear direction by the control current (pulse current) output from the control unit (not shown). As a result, the discharge passage 27b of the oil pump 27 is connected to one of the retard angle oil passage 25 and the advance angle oil passage 26. At the same time, the discharge passage 31 is connected to the other of the retard angle oil passage 25 and the advance angle oil passage 26.

[0058] The computer inside the control unit receives information signals from various sensors such as a crank angle sensor (not shown) (for detecting the engine speed), an air flow meter, an engine water temperature sensor, an engine temperature sensor, a throttle opening sensor, and a cam angle sensor for detecting the current rotation phase of the camshaft 2, and detects the current engine operation state. In addition, the control unit outputs a control current to each coil of the electromagnetic switching valve 28 to control the movement position of the slide valve body and performs switching control on each oil passage 25, 26.

[0059] In addition, if Figure 2 As shown, there is a rotation position ( Figure 2 position) of the locking mechanism 32.

[0060] The locking mechanism 32 mainly includes: a locking hole, which is formed by a locking hole constituting part (not shown) fixed in a fixing hole provided on the inner circumference of the inner side surface of the sprocket 1; a pin receiving hole 33, which is provided in the inner axial direction of the first blade 14a; a locking pin 34, which can be slidably provided in the pin receiving hole 33 and inserted into or pulled out of the locking hole; a release passage (not shown) that allows the locking pin 34 to withdraw from the locking hole 32 and release the lock; and a coil spring that applies force to the locking pin 34 in the direction of the locking hole 32.

[0061] The lock hole provided on the inner side surface of the sprocket 1 is disposed on the fourth shoe 11d side on the retarded angle side. The pin receiving hole 33 is formed through the first vane 14a in the direction of the rotation axis of the rotor 13 .

[0062] The release passage is formed at one side of the first vane 14a, and the lock pin 34 is moved backward by applying oil pressure from one of the retarded angle oil pressure chambers 15a or the advanced angle oil pressure chambers 16d against the spring force of the coil spring. That is, the lock pin 34 receives the operating oil pressure supplied to the retarded angle oil pressure chamber 15a or the advanced angle oil pressure chamber 16d from the release passage, thereby being pulled out from the lock hole and releasing the lock on the vane rotor 9.

[0063] [Function of this embodiment]

[0064] Next, the operation of the valve timing control device in this embodiment will be described.

[0065] When the ignition switch is turned off, the output of the control current from the control unit to the electromagnetic switching valve 28 stops, and the driving of the oil pump 27 stops. Therefore, the slide valve of the electromagnetic switching valve 28 is held in the original position by the spring force, and the supply of oil pressure to each retard angle oil pressure chamber 15a to 15d and each advance angle oil pressure chamber 16a to 16d is stopped. In addition, during the period before the internal combustion engine is completely stopped, the vane rotor 9 rotates relative to the housing 6 toward the most advanced angle side by the alternating torque (negative torque) acting on the camshaft 2 and the torque of the disc spring 36.

[0066] On the other hand, as the supply of oil pressure to the retarded angle oil pressure chamber 15a stops, the oil pressure in the retracting direction does not act on the lock pin 34, so the front end is inserted into the lock hole at the most advanced angle position under the spring force of the coil spring. Figure 3 As shown, one side surface 14f of the first vane 14a of the vane rotor 9 abuts against the opposite side surface of the first shoe 11a and is restricted to a relative rotation position on the most advanced angle side.

[0067] Thereafter, when the ignition switch is turned on to restart the internal combustion engine, the opening and closing timing of the exhaust valve during cranking becomes the most advanced angle side, thereby stabilizing the starting and improving the startability.

[0068] Thereafter, when the operating state of the internal combustion engine changes, the spool of the electromagnetic switching valve 28 communicates the discharge passage 27 b with the advance angle oil passage 26 and communicates the retard angle oil passage 25 with the drain passage 31 by a control current output from the control unit.

[0069] Therefore, the hydraulic oil (oil pressure) discharged from the oil pump 27 is supplied from the advance angle oil passage 26 to the advance angle oil pressure chambers 16a to 16d through the second oil hole 2d, each second camshaft oil passage 19, each second axial oil hole 21, and each second radial oil passage 23. Furthermore, the hydraulic oil (oil pressure) flowing into one advance angle oil pressure chamber 16d flows into the pressure receiving portion of the lock pin 34 through the release passage, and acts in the direction of moving the lock pin 34 backward. Therefore, the lock pin 34 retreats against the elastic force of the spring, and the front end portion is pulled out of the lock hole to release the lock of the vane rotor 9 relative to the housing 6. As a result, the vane rotor 9 is ensured to rotate freely.

[0070] On the other hand, the working oil in each retardation angle oil pressure chamber 15a~15d flows from each first radial oil passage 22, from the first axial oil hole 20 and the first camshaft oil passage 18 into the retardation angle oil passage 25, and is discharged from the drain passage 31 to the oil pan 35 through the electromagnetic switching valve 28.

[0071] Therefore, the pressure in each of the retarded angle oil pressure chambers 15a to 15d becomes low, while the pressure in each of the advanced angle oil pressure chambers 16a to 16d becomes high. Figure 3As shown, the vane rotor 9 is maintained at a relative rotation position in the clockwise direction (advanced angle side), and one side surface 14f of the first vane 14a abuts against the opposite side surface of the first shoe 11a, and is restricted and maintained at the rotation position on the most advanced angle side.

[0072] As a result, the valve overlap between the intake valve and the exhaust valve disappears, and blowback of the combustion gas is suppressed, so that a good combustion state can be obtained, and the fuel consumption rate can be improved and the rotation of the internal combustion engine can be stabilized.

[0073] When the operating state of the internal combustion engine further changes, the spool of the electromagnetic switching valve 28 communicates the discharge passage 27 b with the advance angle oil passage 26 and communicates the retard angle oil passage 25 with the drain passage 31 by the control current output from the control unit.

[0074] Therefore, the working oil discharged from the discharge passage 27b of the oil pump 27 to the retard angle oil passage 25 flows from the first oil hole 2c into the first camshaft oil passage 18, and from there flows into the first axial oil hole 20 and the first radial oil passage 22, and is quickly supplied to each retard angle oil pressure chamber 15a~15d.

[0075] In addition, the working oil in each advanced angle oil pressure chamber 16a~16d is discharged from each second radial oil passage 23 through each second axial oil hole 21, the second camshaft oil passage 19, the second oil hole 2d, the advanced angle oil passage 26 and the electromagnetic switching valve 28 from the drain passage 31 to the oil pan 35.

[0076] Therefore, the pressure in each of the advanced angle oil pressure chambers 16a to 16d becomes low, while the pressure in each of the retarded angle oil pressure chambers 15a to 15d becomes high. Figure 2 As shown, the vane rotor 9 rotates relatively in the counterclockwise direction (retardation angle side) and the other side surface 14e of the first vane 14a contacts the opposite side surface of the first shoe 11d, and is restricted to be maintained at the rotation position on the most retarded angle side. As a result, the valve overlap between the intake valve and the exhaust valve becomes larger, and the internal combustion engine can achieve higher output, etc.

[0077] Furthermore, in the present embodiment, the inner diameters d of the first and second axial oil holes 20 and 21 are formed larger than the inner diameters d1 of the corresponding first and second camshaft oil passages 18 and 19, respectively, and the opening ends of the other ends 18b and 19b of the camshaft oil passages 18 and 19 are arranged within the opening range of the opposite opening ends of the axial oil holes 20 and 21. As a result, the opening ends of the other ends 18b and 19b of the camshaft oil passages 18 and 19 do not deviate in the radial direction at the opening ends of the axial oil holes 20 and 21, and the appropriate communication state can be always maintained. As a result, the flow resistance of the oil flowing from the camshaft oil passages 18 and 19 to the axial oil holes 20 and 21 can be suppressed, and the smooth flow can be ensured.

[0078] Furthermore, by arranging the first and second axial oil holes 20 and 21 to be offset by a predetermined amount α to the radially outer side of the rotor 13, the distance between each axial oil hole 20 and 21 and the first and second radial oil passages 22 and 23 can be increased relative to the inner peripheral surface of the bolt insertion hole 13a formed through the center of the rotor 13. That is, by arranging the first and second axial oil holes 20 and 21 to be offset to the radially outer side, the distances L and L1 between each axial oil hole 20 and 21 and the first and second radial oil passages 22 and 23 can be sufficiently separated relative to the bolt insertion hole 13a.

[0079] Therefore, the wall thickness between each axial oil hole 20, 21, each radial oil passage 22, 23 and the bolt insertion hole 13a can be made larger. As a result, the reduction in the rigidity of the rotor 13 can be suppressed, and the sealing area between the bolt insertion hole 13a and each opening of each axial oil hole 20, 21 and radial oil passage 22, 23 can be made larger, so the sealing performance between the two is good. As a result, the oil in each axial oil hole 20, 21 and each radial oil passage 22, 23 can be suppressed from leaking into the bolt insertion hole 13a.

[0080] In addition, by disposing the axial oil holes 20 and 21 offset to the radial outer side of the rotor 13, the degree of freedom in the layout of the radial oil passages 22 and 23 is increased. That is, as described above, by separating the axial oil holes 20 and 21 from the bolt insertion holes 13a, the degree of freedom in the layout such as the formation angle of the radial oil passages 22 and 23 is increased. Therefore, the versatility for various valve timing control devices is improved.

[0081] Figure 6 is a perspective representation from Figure 5 The diagram shows the flow characteristics of oil flowing from the second camshaft oil passage into the second axial oil hole and the second radial oil passage.

[0082] As described above, the axial center positions P of the axial oil holes 20 and 21 are offset by a predetermined amount α relative to the axial center positions P1 of the camshaft oil passages 18 and 19. Figure 6 As shown, a swirling flow is easily generated in the oil (in a plurality of lines) flowing from the camshaft oil passages 18 , 19 into the radial oil passages 22 , 23 through the axial oil holes 20 , 21 .

[0083] That is, according to the experiment of the inventor of the present application, when the pressure of the oil O flowing into each camshaft oil passage 18, 19 is set to 400 kPa and the flow rate thereof is set to 13 L / min, a spiral swirling flow is generated inside each axial oil hole 20, 21 due to the offset arrangement, and the oil O that becomes the swirling flow flows into each radial oil passage 22, 23. In the long passages 22a, 23a of each radial oil passage 22, 23, the pressure of the oil O becomes 323 kPa and the flow rate becomes 7.6 L / min due to the flow resistance generated by the swirling flow, and in the short passages 22b, 23b, the pressure becomes 357 kPa and the flow rate becomes 5.4 L / min due to the flow resistance generated by the swirling flow. Therefore, the pressure difference between the long passages 22a, 23a and the short passages 22b, 23b is 34 kPa and the flow rate difference is 2.2 L / min, and there is no large difference due to the pressure difference and flow rate difference, and they are substantially equal.

[0084] Therefore, the amount of oil per unit time for the four retarded angle oil pressure chambers 15a to 15d and the four advanced angle oil pressure chambers 16a to 16d can be well-balancedly supplied to any oil pressure chamber from each radial oil passage 22, 23. As a result, since substantially equal oil pressure acts on each vane 14a to 14d, the action responsiveness of the relative conversion angle between the housing 6 and the vane rotor 9 is improved.

[0085] In addition, as described above, since the oil pressure can be quickly supplied to the retarded angle oil pressure chamber 15a and the advanced angle oil pressure chamber 16d, the supply speed of the lock release oil pressure acting on the lock pin 34 of the lock mechanism 32 becomes faster. As a result, the lock release speed of the lock pin 34 becomes faster. Therefore, in the present embodiment in which the switching speed of the conversion angle of the vane rotor 9 becomes faster with the operation change of the internal combustion engine, the first and second camshaft oil passages, the first and second axial oil holes, and the first and second radial oil passages on both the retarded angle side and the advanced angle side are described, but, for example, it is also possible to set only the first on the retarded angle side or the second on the advanced angle side.

Claims

1. A valve timing control device for an internal combustion engine, characterized in that: A housing and a blade rotor are provided. The housing is transmitted with the rotational force from the crankshaft and has an operating chamber inside. The vane rotor is relatively rotatably arranged inside the housing, and comprises: a rotor fixed to the camshaft by a cam bolt; a plurality of vanes provided on the rotor to divide the action chamber into a plurality of first oil pressure chambers and a second oil pressure chamber; a plurality of axial oil holes formed inside the rotor along the rotation axis direction of the rotor, respectively connected to a plurality of camshaft oil passages formed on the camshaft, the inner diameter of the axial oil hole is formed to be larger than the inner diameter of the camshaft oil passage, and the axial position of the axial oil hole is offset radially outward relative to the camshaft oil passage; a first radial oil passage, which is respectively connected to each of the axial oil holes, one straight end opens to one of the first oil pressure chambers, and the other bent end opens to the other first oil pressure chambers.

2. The valve timing control device for an internal combustion engine according to claim 1, characterized in that: The inner diameter of each of the axial oil holes is formed larger than the inner diameter of each of the first radial oil passages, and the axial center position of each of the first radial oil passages is offset toward the radial outside of the rotor relative to the axial center of each of the axial oil holes.

3. The valve timing control device for an internal combustion engine according to claim 2, characterized in that: One circular end portion of the axial oil hole and one circular end portion of the camshaft oil passage opening into the axial oil hole are arranged such that hole edges thereof are inscribed inwardly of the rotor in the radial direction.

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