JP2017057742A - Valve timing control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve timing control device for an internal combustion engine capable of reducing flexural deformation of a cam shaft based on tension of a timing chain.SOLUTION: A valve timing control device for an internal combustion engine includes: a housing body 11 which synchronously rotates with a crank shaft on the basis of rotational force transmitted via a tooth part 18 of a sprocket 13; and a vane rotor 20 which is accommodated on an inner peripheral side of the housing body 11 so as to be relatively rotatable, and synchronously rotates with a cam shaft 2 fixed on the inner peripheral side. The valve timing control device changes a relative rotation phase of the cam shaft 2 to the crank shaft by selectively supplying and discharging fluid pressure to an advance actuation chamber Ad and a retard actuation chamber Re spaced among the respective shoes S1-S4 by the respective vanes V1-V4. The tooth part 18 is provided on a side of the cam shaft 2 with respect to a fixing part X of the cam shaft 2 and the vane rotor 20.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a valve timing control device for an internal combustion engine that controls the opening / closing timing of an intake valve or an exhaust valve of the internal combustion engine according to an operating state.

  As a conventional valve timing control device, for example, one described in Patent Document 1 below is known.

  That is, this valve timing control device is provided integrally with a disc-shaped sprocket that rotates synchronously with the crankshaft via a timing chain, and a bottomed cylindrical housing with a plurality of shoes protruding on the inner peripheral side, A vane rotor that is fastened to one end portion of the camshaft through a boss portion that is inserted and fitted into the sprocket, and a plurality of vanes project from the outer peripheral side, and the vane rotor is relatively disposed on the inner peripheral side of the housing. It is configured by being housed and arranged to be rotatable.

JP 2013-2327 A

  However, in the conventional valve timing control device, since the connecting portion of the vane rotor and the camshaft is provided on the camshaft side of the sprocket in the above configuration, the tension of the timing chain acts on the sprocket. Then, a rotational moment that tilts the housing and the vane rotor toward the camshaft side is generated.

  As a result, there has been a problem that the bending deformation of the camshaft is promoted by the rotational moment, leading to an increase in wear of the bearing portion that rotatably supports the camshaft.

  The present invention was devised in view of the actual situation of the conventional valve timing control device, and provides a valve timing control device for an internal combustion engine that can reduce the bending deformation of the camshaft based on the tension of the timing chain. It is aimed.

  According to the present invention, a substantially cylindrical housing main body having a plurality of shoes projecting on the inner peripheral side, and a plurality of vanes that divide the shoes into an advance working chamber and a retard working chamber on the outer peripheral side. And a vane member whose inner peripheral side is fixed to an end portion of the camshaft, and is extended to one end side in the axial direction of the housing body that is closer to the camshaft side than the fixing portion between the camshaft and the vane member. And a rotational force transmitting part for use in transmitting the rotational force of the crankshaft.

  According to the present invention, when the rotational force transmitting portion is arranged on one end side (camshaft side) in the axial direction from the fixed portion of the vane member and the camshaft, when the tension of the timing chain acts on the rotational force transmitting portion, As a result of a rotating moment that tilts the vane member toward the other end in the axial direction and the housing body toward the one end in the axial direction, the camshaft is deformed less due to the tension of the timing chain. can do.

1 is an exploded perspective view of a valve timing control device for an internal combustion engine according to the present invention. FIG. 2 is a longitudinal sectional view of a valve timing control device for an internal combustion engine shown in FIG. FIG. 2 is a front view of the valve timing control device shown in FIG. 1 with a front plate removed. It is a rear view of the valve timing control apparatus shown in FIG. It is a longitudinal cross-sectional view of the valve timing control apparatus of the internal combustion engine shown in FIG. FIG. 6 is a view corresponding to FIG. 5 showing a longitudinal section of a conventional valve timing control device for an internal combustion engine.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a valve timing control device for an internal combustion engine according to the present invention will be described with reference to the drawings. In the following embodiment, the apparatus is applied to an exhaust-side valve operating apparatus, as in the prior art. Further, for convenience of explanation, the left side of FIG.

  That is, as shown in FIGS. 1 and 2, the valve timing control device 1 includes a sprocket 13 that is rotationally driven by the rotational force of a crankshaft (not shown), and a cam that is provided to be rotatable relative to the sprocket 13. It is interposed between the shaft 2 and the operation is controlled through a predetermined hydraulic supply / exhaust means 5 to convert the relative rotational phases of the both 1 and 2.

  Specifically, the housing 10 is provided integrally with the sprocket 13 and has four first to fourth shoes S1 to S4 projecting on the inner peripheral side, and is relatively rotatable on the inner peripheral side of the housing 10. And a vane rotor 20 that is a vane member that is provided with four first to fourth vanes V1 to V4 projecting on the outer peripheral side. A pair of retarded working chambers (hereinafter abbreviated as “retarded chambers”) Re and advanced working chambers (hereinafter referred to as “retarded chambers”) are provided between the circumferential directions of the shoes S1 to S4 by the vanes V1 to V4. And abbreviated as “advance angle chamber.”) The operation is controlled by selectively supplying hydraulic pressure to the operation chambers Ad, Re from the hydraulic supply / discharge means 5.

  At this time, between the housing 10 and the vane rotor 20, as shown in FIGS. 2 and 4, one end 30 a on the front end side is located on the housing 10 (an inner protrusion 13 a of the sprocket 13 described later), A torsion spring 30 that is a torsion coil spring that biases the vane rotor 20 toward the advance side is provided by fixing the other end 30b on the rear end side to the vane rotor 20 (latching groove 21c described later). Then, immediately before the stop of the engine in which the hydraulic pressure does not act on any of the working chambers Ad and Re due to the urging force of the torsion spring 30, the rotational force in the retarding direction (so-called alternating) transmitted through the camshaft 2 is transmitted. The vane rotor 20 is biased to the advance side against the torque.

  The camshaft 2 is rotatably supported via a bearing portion 3 provided on a cylinder head (not shown), and an exhaust valve (not shown) is connected to a cam cam (not shown) provided at a predetermined position on the outer peripheral portion. Open. The camshaft 2 is provided with a rotor connecting portion 2a that faces the inner peripheral side of a cylindrical portion 17 to be described later and serves for connection with the vane rotor 20 at the front end, and the interior of the rotor connecting portion 2a. In the axial direction, a female screw portion 2b to which a cam bolt 4 used for fastening the vane rotor 20 is screwed is formed.

  The housing 10 has a cylindrical housing body 11 having openings at both ends in the axial direction, a front plate 12 that closes the outer end side opening of the housing body 11, and an inner end side opening of the housing body 11. The sprocket 13 constituting the rear plate is fixed together by a plurality of (four in this embodiment) bolts 14.

  The housing body 11 is integrally formed of a sintered metal material, and the first to fourth shoes S1 to S4 are integrally projected inward at substantially equal positions in the circumferential direction on the inner circumferential side. ing. Each of the first to fourth shoes S1 to S4 has a substantially trapezoidal shape in plan view, and the bolts 14 are inserted in the direction of the internal axis on the base end side to be fastened and fixed to the sprocket 13 together. Bolt insertion holes 11a are formed so as to penetrate therethrough, and substantially prismatic seal members 15 are fitted in seal grooves that are recessed along the axial direction at the respective tip portions.

  The front plate 12 has a disk shape made of a predetermined metal material, and a rotor insertion hole 12a through which a front end portion of a rotor body 21 (described later) is inserted is formed substantially at the center. Four bolt insertion holes 12b for penetrating and fixing to the sprocket 13 when the bolts 14 are inserted are formed at positions corresponding to the bolt insertion holes 11a.

  The sprocket 13 as the rear plate is integrally formed of sintered metal, is provided in a flat shape at the front end portion, and is provided with an end wall 16 that is used to fix the housing body 11 and the front plate 12 together. A hollow cylindrical portion 17 extending in the axial direction from the rear end surface of the sprocket 13 and a radially protruding outer periphery of the rear end portion of the cylindrical portion 17 are engaged with a timing chain (not shown). And a plurality of tooth portions 18 serving as a rotational force transmitting portion that serves to transmit the rotational force of the crankshaft by being wound.

  In particular, in the sprocket 13, as shown in FIG. 2, the tooth portions 18 are arranged so as to be biased toward the rear end side of a boss portion 21 a to be described later of the vane rotor 20. However, the rear end side (the camshaft 2 side) of the fixing portion X between the rotor main body 21 and the camshaft 2 described later facing the camshaft 2 side through the rotor insertion hole 19 penetratingly formed in the central portion of the end wall 16. ).

  With this configuration, the cylindrical portion 17 is also extended to the camshaft 2 side, and a boss portion 21a (described later) of the vane rotor 20 and the camshaft 2 connected to the inner peripheral side of the boss portion 21a. The front end side and the torsion spring 30 disposed in a substantially wound shape on the outer peripheral side of the boss portion 21 a are accommodated on the inner peripheral side of the cylindrical portion 17.

  Further, the inner peripheral side of each tooth portion 18 is formed so as to partially protrude in the inner peripheral side of each tooth portion 18 at a position corresponding to each bolt insertion hole 11a. An inner peripheral protrusion 13a is formed so as to protrude, and in the direction of the inner axis of the inner peripheral protrusion 13a, the male threaded portion of each bolt 14 is screwed so that the housing main body 11 and the front plate 12 are in contact with each other. A female screw hole 13b is provided for co-fastening.

  The vane rotor 20 is integrally formed of a predetermined metal material, and is provided in a substantially cylindrical shape at the center, and is provided with a rotor main body 21 for connection with the camshaft 2 and the hydraulic supply / discharge means 5, and the rotor The first to fourth vanes V <b> 1 to V <b> 4 mainly projecting radially from the outer peripheral side of the main body 21 and serving to separate the retard chamber Re and the advance chamber Ad.

  As shown in FIG. 3, the rotor main body 21 is configured so that the outer diameter thereof is in sliding contact with the seal member 15 fitted to the distal end portion of each of the shoes S1 to S4, and each of the vanes V1 to V4. On both sides, retard angle side oil holes 23 that can communicate with the respective retard angle chambers Re and advance angle side oil holes 24 that can communicate with the respective advance angle chambers Ad are formed penetrating along the radial direction. .

  Further, as shown in FIG. 2, the rear end side of the rotor main body 21 is formed in a slightly stepped diameter shape, and is inserted into the rotor insertion hole 19 so that the inner periphery of the sprocket 13 (tubular portion 17). It is comprised as the boss | hub part 21a used for the latching fixation of the torsion spring 30 by the side. As shown in FIGS. 2 and 4, a fitting recess 21b into which the rotor connecting portion 2a of the camshaft 2 is fitted is formed in the central portion of the boss portion 21a, and an opening of the fitting recess 21b is formed. A locking groove 21c that locks the other end 30b of the torsion spring 30 is formed in the end edge in a radial direction.

  As shown in FIGS. 1 and 3, the vanes V1 to V4 are disposed between the shoes S1 to S4, and are substantially disposed in seal grooves recessed along the axial direction at the distal ends. A rectangular columnar seal member 22 is fitted, and the seal member 22 is in sliding contact with the inner peripheral surface of the housing body 11, so that the space formed between the shoes S1 to S4 is a pair of the pairs. The hydraulic chambers Ad and Re are separated.

  Of the vanes V1 to V4, only the first vane V1 is set to have a larger circumferential width than the other vanes V2 to V4, and abuts against the adjacent shoes S1 and S4 during the maximum relative rotation of the vane rotor 20. As a result, further rotation of the vane rotor 20 is restricted. Further, a well-known lock mechanism 40 for accommodating the phase of the vane rotor 20 when the engine is stopped, which will be described later, is accommodated and disposed inside the first vane V1.

  The lock mechanism 40 is slidably accommodated in a pin accommodation hole 43 formed so as to penetrate the first vane V1 in the inner axial direction, and engages with an engagement hole 44 formed in the sprocket 13 to engage the vane rotor. A substantially cylindrical lock pin 41 that restricts relative movement between the housing 20 and the housing 10 and a spring that is interposed between the lock pin 41 and the front plate 12 and biases the lock pin 41 toward the sprocket 13. 42.

  That is, when the positions of the lock pin 41 and the engagement hole 44 coincide with each other, the front end portion of the lock pin 41 is pushed into the engagement hole 44 by the urging force of the spring 42, and the relative rotation between the housing 10 and the vane rotor 20 is performed. Is regulated (locked). On the other hand, a communication groove 45 that communicates the retard chamber Re and the engagement hole 44 is formed in the inner side surface of the first vane V1 (the end surface facing the sprocket 13). When the hydraulic pressure acts on the distal end side of the lock pin 41 in the engagement hole 44, the lock pin 41 is pushed away by the hydraulic pressure, and the lock is released.

  As shown in FIG. 2, the hydraulic supply / discharge means 5 selectively supplies hydraulic pressure to the working chambers Ad and Re, or discharges hydraulic oil in the working chambers Ad and Re. The retard angle side oil passages 51 connected to the respective retard angle side oil holes 23, the advance angle side oil passages 52 connected to the respective advance angle side oil holes 24, and a known solenoid valve 55. An oil pump 53 that is a hydraulic pressure source that supplies hydraulic pressure to the oil passages 51 and 52 on one side, and a drain passage that is connected to the other oil passages 51 and 52 that are not connected to the oil pump 53 via the electromagnetic valve 55. 54.

  The retard angle side oil passage 51 and the advance angle side oil passage 52 are connected to the retard angle side oil hole 23 and the advance angle side oil hole 24 via a passage constituting member 56 connected to the inner peripheral surface 21d of the front end portion of the vane rotor 20. It is configured to communicate. Specifically, the retard angle side oil passage 51 is formed between the retard angle side connection passage 56 a provided along the internal axial direction of the passage constituting member 56 and the axial direction between the vane rotor 20 and the passage constituting member 56. The retarding angle side oil holes 23 communicate with each other through the communicating chamber 57. On the other hand, the advance side oil passage 52 includes an advance side connection passage 56 b provided in parallel with the retard side connection passage 56 a along the internal axis direction of the passage component member 56, and a distal end portion of the passage component member 56. The advance angle side oil holes 24 communicate with each other through an annular groove 56c provided on the outer peripheral side.

  A plurality of annular groove portions 56d are formed on the outer periphery of the passage constituting member 56, and an annular seal member 58 is fitted into the groove portion 56d, and the seal member 58 is an inner peripheral surface 21d of the front end portion of the vane rotor 20. The space between the communication chamber 57 and the annular groove 56c is sealed.

  The electromagnetic valve 55 is a two-way switching valve, and the oil passages 51 and 52 are controlled by a control signal from an electronic control unit (ECU) (not shown) output based on detection results of various on-vehicle sensors. The connection between the oil pump 53 and the drain passage 54 is selectively switched.

  The characteristic operation of the valve timing control apparatus for an internal combustion engine according to the present invention will be described below with reference to FIGS.

  As shown in FIG. 6, the conventional valve timing control device 100 for an internal combustion engine is configured such that the tooth portion 103 a of the sprocket 103 is positioned on the front end side of the fixed portion Y between the vane rotor 104 and the camshaft 101. Therefore, when the tension Fc of the timing chain (not shown) acts on the sprocket 103, a rotational moment that tilts both the housing 102 and the vane rotor 104 toward the front end side (the opposite camshaft 101 side), that is, the housing 102 is moved to the front end side. A rotational moment M1 ′ that causes the vane rotor 104 to tilt toward the front end side is generated.

  As a result, there has been a problem that the bending deformation of the camshaft 101 is promoted by the both rotational moments M1 'and M2', leading to an increase in wear of the bearing portion 105 that rotatably supports the camshaft 101.

  Further, although the camshaft 2 is bent and deformed by the rotational moments M1 ′ and M2 ′, the vane rotor 104 is inclined, but the passage component member 106 is inclined by being attached to an engine chain case (not shown). Therefore, the sealing performance of the sealing member 107 provided on the outer periphery of the passage constituting member 106 may be deteriorated.

  On the other hand, in the valve timing control apparatus for an internal combustion engine according to the present embodiment, as shown in FIG. 5, each tooth portion 18 of the sprocket 13 is rear end of the fixed portion X between the vane rotor 20 and the camshaft 2. Therefore, when the tension Fc of the timing chain (not shown) acts on each tooth portion 18, the rotational moment that causes the vane rotor 20 to tilt to the front end side as in the conventional case. While M2 is generated, a rotational moment M1 that tilts the housing body 11 toward the rear end side is generated.

  Thus, in the valve timing control device for the internal combustion engine according to the present embodiment, the tooth portions 18 of the sprocket 13 are arranged on the rear end side of the fixed portion X between the vane rotor 20 and the camshaft 2. The camshaft 2 based on the timing chain tension Fc as a result of the rotational moment M1 related to the housing body 11 based on the tension Fc of the timing chain and the rotation moment M2 related to the camshaft 2 acting to cancel each other. Can be reduced.

  In the present embodiment, in particular, the teeth 18 are arranged at the rear end of the sprocket 13, whereby the tension Fc of the timing chain is effectively supported by the bearing 3. As a result, both the moments M1 and M2 themselves based on the tension Fc of the timing chain can be reduced as much as possible, and the bending deformation of the camshaft 2 can be further reduced.

  Furthermore, it becomes possible to accommodate and arrange the torsion spring 30 on the inner peripheral side of the cylindrical portion 17 extending toward the camshaft 2 side by the rear end side arrangement of the respective tooth portions 18. The peripheral wall of the portion 17 can function as a guide for the torsion spring 30. Accordingly, there is an advantage that the degree of freedom in designing the torsion spring 30 can be improved, for example, the urging force of the torsion spring 30 can be further increased.

  In addition, in the present embodiment, since each tooth portion 18 extends to the rear end side from the boss portion 21a of the vane rotor 20, the disposition of the locking groove 21c of the torsion spring 30 in the boss portion 21a is free. The degree of freedom in designing the torsion spring 30 can be improved.

  Further, as described above, the bending deformation of the camshaft 2 is suppressed, so that the inclination of the vane rotor 20 is suppressed. As a result, the sealing performance of the seal member 58 provided on the outer periphery of the passage constituting member 56 is deteriorated. It is also possible to suppress leakage of hydraulic oil from the communication chamber 57 and the like.

  The present invention is not limited to the configuration of the above-described embodiment. For example, the specific configuration of the vane rotor 20, the lock mechanism 40, the hydraulic supply / discharge unit 5, and the like that are not directly related to the features of the present invention is included. The specific axial position of each tooth portion 18 related to the feature can be freely changed according to the specification and cost of the application target as long as the above-described effects of the present invention can be obtained. Is possible.

2 ... Camshaft 11 ... Housing body 18 ... Tooth part (rotational force transmission part)
20 ... Vane rotor (vane member)
S1-S4 ... Shoes V1-V4 ... Vane Ad ... Advance chamber (advance chamber)
Re ... retarding chamber (retarding chamber)
X: Fixed part

Claims (6)

A substantially cylindrical housing body with a plurality of shoes projecting on the inner peripheral side;
A vane member having a plurality of vanes that are separated into an advance working chamber and a retard working chamber between the shoes on the outer peripheral side, and an inner peripheral side fixed to an end of the camshaft;
A rotational force transmitting portion that extends toward one end in the axial direction of the housing body that is closer to the camshaft than the fixed portion between the camshaft and the vane member, and serves to transmit the rotational force of the crankshaft;
A valve timing control apparatus for an internal combustion engine, comprising:   2. The valve of the internal combustion engine according to claim 1, wherein a biasing member that biases the vane member toward one side in a rotational direction with respect to the housing main body is disposed on one axial end side of the housing main body. Timing control device.   The valve timing control device for an internal combustion engine according to claim 2, wherein the rotational force transmitting portion is formed in a substantially cylindrical shape and is provided so as to surround the urging member.   The vane member has a boss portion into which one end portion of the camshaft is fitted on one end side in the axial direction, and one end portion of the biasing member is fixed to the boss portion. Item 4. The valve timing control device for an internal combustion engine according to Item 3.   5. The internal combustion engine according to claim 4, wherein the biasing member is constituted by a torsion coil spring having one end portion locked to the boss portion and the other end portion locked to the housing body. Valve timing control device.   6. The valve timing control device for an internal combustion engine according to claim 5, wherein the rotational force transmitting portion extends to one end side in the axial direction from the boss portion.

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