Valve timing control device for internal combustion engine

Abstract

To provide a valve timing control device capable of suppressing deterioration of efficiency of manufacturing work and assembling work to suppress cost increase in each work.SOLUTION: A housing body 2a includes four shoes 4a-4d projecting from an inner peripheral surface 2b to a radial inner side, and each of the shoes is formed to have a tapered surface shape in which a diameter of each tip surface 8a-8d on the radial inner side contracts from one end surface in a direction of a rotating shaft of the housing to the other end direction. A vane rotor 3 includes a plurality of vanes 10a-10d and a cylindrical rotor 9 formed integrally with the plurality of vanes. The rotor is provided so that an outer peripheral surface 9c thereof slides on the tip surface of each of the plurality of shoes, and is formed to have a tapered surface shape in which a diameter of the outer peripheral surface contracts from one end surface 9a in the direction of the rotating shaft to the other end surface 9b direction following each tip surface with the tapered surface shape of the plurality of shoes.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] A conventional valve timing control device for an internal combustion engine is disclosed in, for example, Patent Document 1 below.

[0003] This valve timing control device has a plurality of shoes integrally provided on the inner peripheral surface of a housing, and a vane rotor disposed within the housing so as to be relatively rotatable.

[0004] The housing is made of metal and is generally cylindrical, with a timing sprocket attached to its outer periphery, to which torque is transmitted from the crankshaft via a timing chain. The housing has openings at both ends in the direction of the rotational axis that are closed by a front plate and a rear plate. Each shoe protrudes radially inward from the inner circumferential surface of the housing, with each tip end surface arcuate along the circumferential direction of the housing and linear (vertical) along the direction of the rotational axis.

[0005] On the other hand, the vane rotor has a cylindrical rotor that is integrally formed from metal material and fastened with bolts to one end of the camshaft in the direction of the rotational axis, and a plurality of vanes that are provided on the outer surface of the rotor and separate a plurality of retard hydraulic chambers and advance hydraulic chambers between each of the shoes.

[0006] The rotor has an outer circumferential surface that is slidable against the tip surfaces of the shoes, and a cylindrical portion that is coupled to the camshaft is integrally formed on its inner circumferential surface on the rear plate side in the rotational axis direction. The rotor's outer circumferential surface is formed linearly along the rotational axis direction, just like the tip surfaces of the shoes, and a metal seal structure is formed between the rotor and the tip surfaces of the shoes with a small clearance, and no seal members are required. This seal-free structure, or the elimination of seal members, improves manufacturing and assembly operability, reduces costs, and increases the conversion angle of the vane rotor relative to the housing.

[0007] Each vane is provided at its tip with a seal member for sealing the gap between the vane and the inner peripheral surface of the housing. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-204726 Summary of the Invention [Problem to be solved by the invention]

[0009] In the conventional valve timing control device described in the publication, no seal is provided between the tip end surface of each shoe of the housing and the outer peripheral surface of the rotor of the vane rotor. However, if this seal is eliminated, there is a risk that the amount of oil leaking from the retard hydraulic chamber or advance hydraulic chamber, where the internal oil pressure is high during relative rotation control of the vane rotor, through the minute clearance will increase and into the adjacent hydraulic chamber, resulting in a deterioration in control performance.

[0010] Therefore, in order to reduce the amount of oil leakage, measures have been taken to make the clearance between the tip end surface of each shoe of the housing and the outer circumferential surface of the rotor as small as possible.

[0011] However, if the clearance between the tip surface of each shoe and the outer peripheral surface of the rotor is made as small as possible, the range of dimensional tolerance between the tip surface of each shoe and the outer peripheral surface of the rotor during manufacturing must be set to an extremely small range.

[0012] This makes it difficult to manufacture the housing and the vane rotor, which leads to a rise in manufacturing costs, and may also make it difficult to assemble the vane rotor to the housing.

[0013] The present invention was devised in consideration of the above-mentioned conventional technical problems, and has as its object to provide a valve timing control device that can set the range of dimensional tolerance between the tip surfaces of each shoe of the housing and the outer peripheral surface of the rotor of the vane rotor as small as possible, while suppressing a decrease in the efficiency of the manufacturing and assembly operations and suppressing an increase in the costs of each of these operations. [Means for solving the problem]

[0014] In one aspect of the present invention, the housing has a plurality of shoes protruding radially inward from the inner peripheral surface, and the radially inner tip surfaces of the plurality of shoes are formed in an arc shape along the circumferential direction of the housing, and the entire tip surfaces are formed in a tapered shape that decreases in diameter from one end of the housing in the rotational axis direction to the other end, The vane rotor has a plurality of vanes, each of whose tip surfaces is slidably mounted on the inner peripheral surface of the housing and which form working chambers between itself and the plurality of shoes, and a cylindrical rotor which is formed integrally with the plurality of vanes and fixed to the camshaft, and is characterized in that the rotor has an outer peripheral surface which is slidably mounted on the tip surfaces of the plurality of shoes, and the outer peripheral surface is formed in a tapered shape which reduces in diameter from one end of the rotational axis direction to the other end, following the tapered tip surfaces of the plurality of shoes. [Effects of the Invention]

[0015] According to the present invention, the range of dimensional tolerance between the tip surface of each shoe of the housing and the outer peripheral surface of the rotor of the vane rotor can be set as small as possible, while suppressing a decrease in the efficiency of manufacturing and assembly operations and suppressing an increase in the costs of each operation. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a configuration diagram showing a first embodiment of a valve timing control device according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Figure 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 4] 10A and 10B are schematic diagrams showing the process of assembling a vane rotor into the housing used in this embodiment, in which FIG. 10A shows a state in which the vane rotor is about to be lowered from an upper position into the housing, and FIG. 10B is an explanatory diagram showing the vane rotor housed inside the housing. [Figure 5] FIG. 3 is a configuration diagram showing a second embodiment of a valve timing control device according to the present invention. [Figure 6] FIG. 6 is a cross-sectional view taken along line CC in FIG. 5. [Figure 7] FIG. 6 is a cross-sectional view taken along line DD in FIG. 5. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a valve timing control device for an internal combustion engine according to the present invention is applied to, for example, an intake valve side will be described below with reference to the drawings. [First embodiment] Fig. 1 is a configuration diagram showing a first embodiment of a valve timing control device according to the present invention, Fig. 2 is a cross-sectional view taken along line AA in Fig. 1, and Fig. 3 is a cross-sectional view taken along line BB in Fig. 1. Note that Figs. 1 to 3 only show the configuration of a housing used in the first embodiment and a vane rotor housed and disposed inside the housing.

[0018] First, a brief description of the basic configuration of a valve timing control device will be given. This valve timing control device includes a sprocket, which is a driving rotor that is rotated by the engine crankshaft via a timing chain, a camshaft on the intake valve side that is rotatable relative to the sprocket, a phase change mechanism that is disposed between the sprocket and the camshaft and changes the relative rotation phase between them, and a hydraulic circuit that operates the phase change mechanism.

[0019] As shown in Figure 1, the sprocket 1 has an annular sprocket body 1a and a gear portion 1b, which is integrally formed on the outer periphery of one end of the sprocket body 1a in the axial direction and around which a timing chain is wound. The sprocket body 1a is integrally formed from high-hardness steel and serves as a rear plate that closes the rear-end opening of a housing body 2a (described later). A support hole 1c is formed through the center of the sprocket body 1a to rotatably support the outer periphery of a vane rotor 3 (described later). Multiple (four in this embodiment) female threaded holes 1d are formed through the outer periphery of the sprocket body 1a at predetermined circumferential positions.

[0020] The camshaft on the intake valve side is rotatably supported by the cylinder head via a cam bearing, and multiple drive cams that open and close the multiple intake valves, which are engine valves, are fixed integrally to its outer circumferential surface in the axial direction.

[0021] As shown in Figures 1 to 3, the phase change mechanism comprises a housing 2 integrally bolted to the sprocket 1, a vane rotor 3 fixed to the intake side camshaft with a cam bolt and accommodated inside the housing 2 so as to be able to rotate relative to the sprocket 1, and a plurality of (four in this embodiment) retard hydraulic chambers 5a to 5d and advance hydraulic chambers 6a to 6d which are working chambers separated by the vane rotor 3 and a plurality of (four in this embodiment) shoes 4a to 4d which are integrally formed on the inner surface of the housing main body 2a of the housing 2.

[0022] The housing 2 has a housing body 2a formed into a cylindrical shape from sintered metal material obtained by compressing and sintering metal powder, a front plate (not shown) that closes the front end opening of the housing body 2a in the direction of the rotation axis, and the sprocket body 1a as a rear plate that closes the rear end opening of the housing body 2a.

[0023] The housing body 2a is integrally provided with the four shoes 4a to 4d at approximately equidistant positions in the circumferential direction of its inner peripheral surface, protruding inward of the housing body 2a, i.e., toward the rotation axis center. As shown in Figure 1, each of the shoes 4a to 4d is formed in an approximately trapezoidal shape when viewed from the front, and a bolt insertion hole 7 is formed inside each shoe 4a to 4d in the direction of the rotation axis of the housing 2.

[0024] The first to fourth shoes 4a to 4d are arranged so that their respective tip surfaces 8a to 8d can slide on the outer peripheral surface 9c of a rotor 9 (described later) of the vane rotor 3. Each of the tip surfaces 8a to 8d is formed in an arc shape along the circumferential direction of the housing body 2a, and is tapered so that its diameter decreases from one end surface on the front plate side to the other end surface on the sprocket body 1a side. That is, as shown in Figure 2, the taper angle θ of each of the tip surfaces 8a to 8d is set at an angle of approximately 5° with respect to a horizontal reference line P in the direction of the rotation axis, and the entire shoe 4a to 4d is formed in a truncated cone shape.

[0025] The front plate (not shown) is formed into a disk shape by press-molding, for example, an iron-based metal plate, and the outer periphery of the inner periphery abuts on one end face of the housing body 2a in the rotational axis direction, while one end face of the vane rotor 3 in the rotational axis direction can slide against the inner periphery of the inner periphery via a small gap, thereby providing a metal seal function.

[0026] The housing body 2a, the front plate, and the sprocket body 1a (rear plate) are fastened together by four bolts (not shown) inserted into the bolt insertion holes 7 of the front plate and each shoe 4a to 4d, and fastened into the female threaded hole 1d of the sprocket body 1a.

[0027] The vane rotor 3 is integrally formed from a sintered metal material obtained by compressing and sintering metal powder, and as shown in Figures 1 to 3, has a rotor 9 fixed to one end of the camshaft by a cam bolt, and four first to fourth vanes 10a to 10d provided radially outward from the outer peripheral surface 9c of the rotor 9 at positions equidistantly spaced approximately 90° apart in the circumferential direction.

[0028] The rotor 9 is formed in a roughly cylindrical shape that is long in the direction of the rotation axis, and one end face 9a in the direction of the rotation axis is arranged so that it can slide on the inner surface of the front plate, while the other end face 9b on the sprocket 1 side is integrally provided with a support part 11, which is a stepped, small-diameter cylindrical part that extends in the direction of the camshaft.

[0029] Furthermore, a relatively large-diameter fitting hole 12 is formed through the rotor 9 from one end face 9a in the axial direction of the interior of the support part 11. A passage component (described later) is fitted into the fitting hole 12. An annular fitting groove 12a is formed in the bottom wall of the fitting hole 12 on the support part 11 side, into which the shaft of a cam bolt is fitted.

[0030] The outer peripheral surface of the support portion 11 is bearing-fitted into the support hole 1c of the sprocket body 1a, and supports the entire sprocket 1 so that it can rotate.

[0031] 2 and 3, the rotor 9 has an outer circumferential surface 9c between one end face 9a and the other end face 9b in the rotation axis direction, which is formed as a tapered surface with a diameter that decreases from the one end face 9a side toward the other end face 9b side. That is, the outer circumferential surface 9c has a taper angle θ1 from the one end face 9a to the other end face 9b, which is set to the same approximately 5° following the taper angle θ of each of the tip faces 8a to 8d of each of the shoes 4a to 4d, and is formed in the same truncated cone shape.

[0032] As shown in FIG. 1, each vane 10a to 10d is disposed between each shoe 4a to 4d, and each has a sealing member 13a to 13d provided on its arc-shaped tip surface to seal between the vane 10a to 10d and the inner peripheral surface 2b of the housing main body 2a.

[0033] When the vane rotor 3 rotates relatively toward the advance side (rotates clockwise in FIG. 1), one side of the first vane 10a abuts against the side of the opposing first shoe 10a, restricting the rotation position on the maximum advance side. When the vane rotor 3 rotates relatively toward the retard side (rotates counterclockwise in FIG. 1), the other side of the first vane 10a abuts against the side of the opposing fourth shoe 10d, restricting the rotation position on the maximum retard side.

[0034] The first vane 10a has a retaining hole 14 formed therethrough, in which a lock pin of a locking mechanism is slidably held in the internal axial direction.

[0035] Each of the retard hydraulic chambers 5a to 5d and each of the advance hydraulic chambers 6a to 6d are connected to the hydraulic circuit via four retard side oil holes 15 and four advance side oil holes 16 that are formed in a roughly radial pattern inside the rotor 9.

[0036] The hydraulic circuit basically selectively supplies or discharges hydraulic oil (hydraulic pressure) to each of the retard and advance hydraulic chambers 5a-5d, 6a-6d, and as shown in Figure 1, it includes a retard oil passage that supplies or discharges hydraulic pressure to each of the retard hydraulic chambers 5a-5d via each of the retard-side oil holes 15, an advance oil passage that supplies or discharges hydraulic pressure to each of the advance hydraulic chambers 6a-6d via each of the advance-side oil holes 16, an oil pump that selectively supplies hydraulic oil to each of the oil passages, and an electromagnetic switching valve that switches the flow path of the retard oil passage and the advance oil passage depending on the engine operating state. Note that a portion of the hydraulic circuit supplies hydraulic pressure to unlock a lock mechanism (described later), and an ECU (not shown) controls the relative supply and discharge of hydraulic pressure to each of the retard and advance hydraulic chambers 5a-5d, 6a-6d.

[0037] A locking mechanism is also provided to hold the vane rotor 3 at an intermediate rotational position between the most advanced rotational position and the most retarded rotational position relative to the housing 2. The locking mechanism is a well-known structure, and therefore a detailed description thereof will be omitted.

[0038] The passage component (not shown) has a cylindrical tip that is inserted into fitting hole 12, and is formed therein with a plurality of corresponding communication passages that connect the retard oil passage with each of the retard-side oil holes 15 and the advance oil passage with each of the advance-side oil holes 16. [Effects of this embodiment] The operation of this embodiment will be described below with reference to FIG.

[0039] 4A and 4B are schematic diagrams showing the process of assembling a vane rotor into the housing body used in this embodiment, where (a) shows the vane rotor being lowered from an upper position into the housing, and (b) is an explanatory diagram showing the vane rotor housed inside the housing. Note that Fig. 4 shows an application to a general valve timing control device in which the outer diameter of the housing 2 is set to approximately 10 cm and the axial width is set to approximately 2.5 cm. As mentioned above, the taper angles θ and θ1 of the tip surfaces 8a to 8d of the shoes 4a to 4d and the outer peripheral surface 9c of the rotor 9 are set to approximately 5°.

[0040] First, as shown in Fig. 4(a), the housing 2 is placed and fixed on the upper surface of a base (not shown), and the rotor 9 of the vane rotor 3 is inserted from above between the tip surfaces 8a-8d of the shoes 4a-4d of the housing body 2a, with the other end surface 9b on the small diameter side facing downward. In this state, the radial distance L between the opening edge on the large diameter side of the tip surfaces 8a-8d of the shoes 4a-4d and the hole edge on the other end surface 9b on the small diameter side of the rotor 9 is relatively large, approximately 2.2 mm. At this time, the vanes 10a-10d already have seal members 13a-13d housed and held in the seal grooves formed in their tip surfaces.

[0041] Therefore, in this embodiment, a larger clearance can be ensured when inserting the vane rotor into a conventional housing, which are formed linearly. This is because the tip surfaces 8a to 8d and the outer peripheral surface 9c of the rotor 9 are each formed into a tapered surface.

[0042] Thereafter, as shown in Figure 4(b), when the entire rotor 9 of the vane rotor 3 is fully inserted between the shoes 4a-4d of the housing body 2a, a clearance C is formed between the tip end surfaces 8a-8d of the shoes 4a-4d and the outer peripheral surface 9c of the rotor 9. The width W of this clearance C is approximately 0.05 mm. The width W of this minute clearance C is approximately the same as that of the conventional one, and a sufficient sealing function is exerted between the retard hydraulic chambers 5a-5d and the adjacent advance hydraulic chambers 6a-6d during hydraulic control.

[0043] The inventors of the present application conducted an experiment to compare the amount of oil leakage between the hydraulic chambers 5a-5d and 6a-6d during control between a conventional control device and the control device of this embodiment. In this experiment, the conditions used were, for example, oil with a viscosity of 5W-30, a temperature environment of 80°C, and the oil supply rate at the inlet to each hydraulic chamber was 3 L / min.

[0044] The results of this experiment showed that the conventional device had an average oil leakage rate of approximately 0.47 L / min, while the device of this embodiment had an average leakage rate of approximately 0.50 L / min, meaning that the device of this embodiment had an average leakage rate of approximately 0.03 L / min more. However, this increase in leakage rate does not affect the control accuracy of the valve timing control device and is within the acceptable range for the control device.

[0045] As described above, in this embodiment, by forming the tip surfaces 8a to 8d of the shoes 4a to 4d of the housing body 2a and the outer peripheral surface 9c of the rotor 9 into a tapered shape, it is possible to set the range of dimensional tolerance between the tip surfaces 8a to 8d of the shoes 4a to 4d and the outer peripheral surface 9c of the rotor 9 as small as possible, and to facilitate the manufacturing and assembly work of the vane rotor 3 with respect to the housing 2. As a result, it is possible to prevent a decrease in the efficiency of the manufacturing and assembly work and to prevent an increase in the cost of each work.

[0046] Furthermore, the assembly work of the vane rotor 3 to the housing 2 can be performed with the precision of existing assembly equipment, which also contributes to suppressing cost increases.

[0047] Furthermore, in this embodiment, as described above, during assembly, the outer peripheral surface 9c of the rotor 9 of the vane rotor 3 automatically conforms to the tip surfaces 8a to 8d of the shoes 4a to 4d of the housing 2, thereby improving centering performance.

[0048] Furthermore, as described above, the vane rotor 3 is formed by sinter molding, and the tapered outer peripheral surface 9c of the rotor 9 is formed as a draft taper during sinter molding, which makes the sinter molding operation easier. Second Embodiment Figures 5 to 7 show a second embodiment of a valve timing control device according to the present invention. The basic configuration is the same as that of the first embodiment, but in this embodiment, the inner surface 2b of the housing body 2a and the tip surfaces of each of the vanes 10a to 10d of the vane rotor 3 are formed into tapered surfaces.

[0049] FIG. 5 is a configuration diagram of a valve timing control device according to a second embodiment, FIG. 6 is a cross-sectional view taken along line CC in FIG. 5, and FIG. 7 is a cross-sectional view taken along line DD in FIG.

[0050] That is, the tip surfaces 8a to 8d of the shoes 4a to 4d of the housing body 2a and the outer peripheral surface 9c of the rotor 9 of the vane rotor 3 have a taper angle θ (θ1) set to approximately 5°, as in the first embodiment, as shown in Figure 6.

[0051] 7, the inner peripheral surface 2b of the housing body 2a is tapered so that the diameter decreases from one end face 2c of the housing body 2a to the other end face 2d in the direction of the rotational axis. On the other hand, the tip faces 10e to 10h of the vanes 10a to 10d of the vane rotor 3 do not include a seal member and are tapered so that the diameter decreases from one end face 9a to the other end face 9b of the rotor 9 in the direction of the rotational axis.

[0052] That is, the inner peripheral surface 2b of the housing body 2a and the tip surfaces 10e to 10h of the vanes 10a to 10d have tapered angles θ and θ1 in the diameter reduction direction that are set at an angle of approximately 5° relative to a horizontal reference line P1 in the direction of the rotation axis.

[0053] 4(a), when the vane rotor 3 is inserted into the housing body 2a from above, the radial distance L between the large-diameter opening edge of each of the tip surfaces 8a-8d of each of the shoes 4a-4d and the hole edge of the other end surface 9b of the rotor 9 on the small-diameter side is relatively large, approximately 2.2 mm, as in the first embodiment. In this state, the radial distance between the large-diameter opening edge of the inner circumferential surface 2b of the housing body 2 and the small-diameter end edge of each of the tip surfaces 10e-10h of each of the vanes 10a-10d is also relatively large, approximately 2.2 mm.

[0054] Therefore, when the vane rotor 3 is subsequently lowered and fully inserted inside the inner circumferential surface 2b of the housing body 2 and between the shoes 4a-4d, as in the case shown in FIG. 4(b), a clearance C is formed between the tip surfaces 8a-8d of the shoes 4a-4d and the outer circumferential surface 9c of the rotor 9, and a clearance C1 is also formed between the inner circumferential surface 2b of the housing body 2 and the tip surfaces 10e-10h of the vanes 10a-10d. Each of these clearances C and C1 has a width W of approximately 0.05 mm. Because the width W of these minute clearances C and C1 is sufficiently small, a sealing function is exerted between the retard hydraulic chambers 5a-5d and the adjacent advance hydraulic chambers 6a-6d during hydraulic control, and the amount of oil leakage can be sufficiently reduced.

[0055] As described above, in the second embodiment, in addition to the tip surfaces 8a to 8d of each shoe 4a to 4d and the outer peripheral surface 9c of the rotor 9 being tapered, the inner peripheral surface 2b of the housing main body 2 and the tip surfaces 10e to 10h of each vane 10a to 10d are also formed into tapered surfaces.

[0056] Therefore, even if the dimensional tolerances of the respective parts are reduced, the work of assembling the vane rotor 3 into the housing body 2 becomes easier.

[0057] Furthermore, the housing body 2a and the vane rotor 3 are each formed by sintering, and the tapered inner peripheral surface 2c of the housing body 2a, the tip surfaces 8a-8d of each of the shoes 4a-4d, and the tapered outer peripheral surface 9c of the rotor 9 and the tip surfaces 10e-10h of each of the vanes 10a-10d are formed as draft tapers during sintering. This further improves the sintering workability of the housing body 2a and the vane rotor 3. [Explanation of symbols]

[0058] 1...sprocket, 1a...sprocket body, 2...housing, 2a...housing body, 2b...inner peripheral surface, 3...vane rotor, 4a to 4d...shoe, 5a to 5d...retard hydraulic chamber, 6a to 6d...advance hydraulic chamber, 8a to 8d...shoe tip surface, 9...rotor, 9a...one end surface, 9b...other end surface, 9c...outer peripheral surface, 10a to 10d...vane, 10e to 10h...vane tip surface, 13a to 13d...sealing member.

Claims

1. a cylindrical housing to which rotational force from a crankshaft is transmitted and which has an opening at an end in the rotational axis direction; and a vane rotor housed and disposed within the housing so as to be rotatable relative to the housing; The housing has a plurality of shoes protruding radially inward from an inner circumferential surface thereof, The plurality of shoes each have a radially inner tip end surface formed in an arc shape along the circumferential direction of the housing, and each tip end surface is formed as a tapered surface whose diameter decreases from one end toward the other end in the direction of the rotation axis of the housing, the vane rotor includes a plurality of vanes, each of whose tip end surfaces is slidably mounted on an inner peripheral surface of the housing and which form working chambers between the vanes and the plurality of shoes; and a cylindrical rotor which is integral with the plurality of vanes and fixed to a camshaft, a rotor having an outer peripheral surface that slides against the tip surfaces of the plurality of shoes, the outer peripheral surface being formed into a tapered surface shape that reduces in diameter from one end in the rotational axis direction to the other end in accordance with the tapered tip surfaces of the plurality of shoes.

2. 2. A valve timing control device for an internal combustion engine according to claim 1, The inner peripheral surface of the housing is formed into a tapered surface whose diameter decreases from one end to the other end in the rotation axis direction, a tip end surface of each of the plurality of vanes formed in a tapered shape that reduces in diameter from one end in the rotational axis direction to the other end in accordance with the tapered inner peripheral surface of the housing;

3. 2. A valve timing control device for an internal combustion engine according to claim 1, The valve timing control device for an internal combustion engine, wherein the vane rotor is formed by sinter molding, and the tapered outer peripheral surface of the rotor is formed as a draft taper during sinter molding.

4. 2. A valve timing control device for an internal combustion engine according to claim 1, 10. A valve timing control device for an internal combustion engine, wherein no sealing member is provided on the tip end surface of each of said shoes.

5. 3. A valve timing control device for an internal combustion engine according to claim 2, a vane rotor provided on the housing and a vane rotor provided on the vane rotor; a vane timing control device for an internal combustion engine, the valve timing control device being characterized in that the housing and the vane rotor are each formed by sintering, and the tapered inner peripheral surface of the housing and the leading end surfaces of each shoe, as well as the tapered outer peripheral surface of the vane rotor and the leading end surfaces of each vane, are formed as draft tapers during sintering.

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