Continuously variable valve opening duration device and engine equipped with the device

Abstract

The present invention relates to a continuously variable valve opening duration device and an engine provided with the device. The continuously variable valve opening duration device comprises: a camshaft, a cam unit, a guide bracket, an inner wheel, a wheel cover, a worm wheel, a control shaft and an upper bushing, wherein a cam is formed on the cam unit; the guide bracket comprises an upper guide boss; the inner wheel is configured to transmit the rotation of the camshaft to the cam unit; the inner wheel is rotatably inserted into the wheel cover, wherein a guide thread is formed on a part of the wheel cover, and the guide shaft is formed to be movably inserted into the upper guide boss; an internal thread combined with the guide thread is formed in the worm wheel, and an external thread is formed on the worm wheel; a control worm combined with the external thread is formed on the control shaft; and the upper bushing is mounted on the lower part of the upper guide boss to support the guide shaft.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] The present application claims priority to Korean Patent Application No. 10-2020-0069740 filed on Jun. 9, 2020, which is incorporated herein in its entirety for all purposes by this reference. Technical Field

[0003] The present invention relates to a continuously variable valve opening duration device and an engine provided with the device. More particularly, the present invention relates to such a continuously variable valve opening duration device and an engine provided with the device, which can change the valve opening duration according to the operating conditions of the engine with a simple structure. Background Art

[0004] The internal combustion engine generates power by burning the fuel in the combustion chamber in the air medium sucked into the combustion chamber. The intake valve is operated by the camshaft to suck air, and the air is sucked into the combustion chamber when the intake valve is open. In addition, the exhaust valve is operated by the camshaft, and the combustion gas is discharged from the combustion chamber when the exhaust valve is open.

[0005] The optimal operation of the intake valve and the exhaust valve depends on the engine speed. That is, the optimal lift or the optimal opening / closing timing of the valve depends on the engine speed. In order to obtain such an optimal valve operation depending on the engine speed, various studies have been conducted, such as the design of multiple cams and continuously variable valve lift (CVVL), which can change the valve lift according to the engine speed.

[0006] In order to obtain such an optimal valve operation depending on the engine speed, research has been conducted on a continuously variable valve timing (CVVT) device that enables different valve timing operations according to the engine speed. A general CVVT can change the valve timing with a fixed valve opening duration.

[0007] The information disclosed in the background section of the present invention is only intended to deepen the understanding of the general background technology of the present invention, and should not be regarded as acknowledging or suggesting in any form that the information constitutes the prior art already known to those skilled in the art. Summary of the invention

[0008] Various aspects of the present invention are directed to providing a continuously variable valve opening duration apparatus and an engine provided with the apparatus, which can change the opening duration of a valve according to an operating condition of the engine and reduce noise and vibration.

[0009] According to various exemplary embodiments of the present invention, a continuously variable valve opening duration device may include: a camshaft, a cam unit, a guide bracket, an inner wheel, a wheel cover, a worm wheel, a control shaft and an upper bushing, wherein the cam is formed on the cam unit, wherein the camshaft is inserted into the cam unit; the guide bracket includes an upper guide boss; the inner wheel is configured to transmit the rotation of the camshaft to the cam unit; the inner wheel is rotatably inserted into the wheel cover, wherein a guide thread is formed on a portion of the wheel cover, and the guide shaft is formed to be movably inserted into the upper guide boss; an internal thread combined with the guide thread is formed in the worm wheel, and an external thread is formed on the worm wheel; a control worm combined with the external thread is formed on the control shaft; and the upper bushing is installed at the lower part of the upper guide boss to support the guide shaft.

[0010] The continuously variable valve opening duration device may further include: a lower guide boss formed on the guide bracket; and a guide rod formed at the wheel cover and inserted into the lower guide boss to guide the movement of the wheel cover.

[0011] The continuously variable valve opening duration apparatus may further include a lower bushing installed on a lower portion of the lower guide boss to support the guide rod.

[0012] The center portion of the inner wheel may be offset from an imaginary line connecting the upper guide boss and the lower guide boss.

[0013] The continuously variable valve opening duration apparatus may further include an insert installed between the wheel house and the guide bracket.

[0014] The insert may be fixed to either the wheel housing or the guide bracket.

[0015] The insert may be made of a plastic material.

[0016] The insert may be formed in a "U" shape in cross section.

[0017] A control shaft hole supporting the control shaft may be formed at the guide bracket.

[0018] The continuously variable valve opening duration apparatus may further include a control shaft bearing installed on the control shaft hole to support rotation of the control shaft.

[0019] The continuously variable valve opening duration apparatus may further include a thrust bearing mounted on the upper guide boss to support the worm gear.

[0020] The continuously variable valve opening duration apparatus may further include a step surface, and the step surface preventing the wheel cover from rotating is formed at the guide bracket.

[0021] The continuously variable valve opening duration device may further include: a first sliding hole and a second sliding hole, a cam groove, a roller wheel and a roller cam, wherein the first sliding hole and the second sliding hole are respectively formed at the inner wheel; the cam groove is formed at the cam unit; the roller wheel is connected to the camshaft and can be rotatably inserted into the first sliding hole; the roller cam can be slidably inserted into the cam groove and can be rotatably inserted into the second sliding hole.

[0022] The roller cam may include: a roller cam body, a cam head, and a protrusion, wherein the roller cam body is slidably inserted into the cam groove; the cam head is rotatably inserted into the second sliding hole; and the protrusion is configured to prevent the roller cam from being removed.

[0023] The roller may include: a wheel body and a wheel head, the wheel body being slidably connected to the cam shaft; and the wheel head being rotatably inserted into the first sliding hole.

[0024] The continuously variable valve opening duration device may further include: a camshaft oil hole, a wheel body oil hole and an oil groove, wherein the camshaft oil hole is formed in the camshaft along the longitudinal direction of the camshaft; the wheel body oil hole is formed at the wheel body of the roller and is configured to be connected to the camshaft oil hole; the oil groove is formed at the wheel head of the roller and is configured to be connected to the wheel body oil hole.

[0025] The cam unit may include first and second cam portions respectively arranged corresponding to the cylinder and the adjacent cylinder, and the inner wheel may include first and second inner wheels respectively transmitting rotation of the camshaft to the first and second cam portions.

[0026] The first inner wheel and the second inner wheel are rotatably connected to each other.

[0027] The continuously variable valve opening duration apparatus further includes a first bearing and a second bearing which are internally arranged in the wheel housing and are configured to support the first inner wheel and the second inner wheel, respectively.

[0028] An engine according to various exemplary embodiments of the present invention may be provided with a continuously variable valve opening duration apparatus.

[0029] As described above, the continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention can change the opening duration of the valve according to the operating condition of the engine with a simple configuration.

[0030] In various exemplary embodiments of the present invention, the continuously variable valve opening duration apparatus is configured to prevent wear and enhance strength by applying a bushing between a wheel cover and a guide bracket.

[0031] The continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention prevents the wheel cover from rotating and reduces noise and vibration by applying an insert between the wheel cover and a guide bracket.

[0032] The continuously variable valve opening duration apparatus according to the exemplary embodiment of the present inventive concept may be downsized, so that the overall height of the valve mechanism may be reduced.

[0033] Since the continuously variable valve opening duration device can be applied to existing engines without much modification, productivity can be improved and production costs can be reduced.

[0034] Even if there are manufacturing errors in components, the continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention can reduce noise and vibration by applying the wheel body elastic portion.

[0035] The methods and apparatus of the present invention have other features and advantages that will be apparent from, or will be described in detail in, the accompanying drawings and subsequent detailed descriptions incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a perspective view of an engine provided with a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0037] Figure 2 is a side view of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0038] Figure 3 It is an exploded perspective view of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0039] Figure 4 It is a partial perspective view of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0040] Figure 5 For along Figure 1 Cross-sectional view obtained along line V-V.

[0041] Figure 6 It is a perspective view of a wheel cover applied to the continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0042] Figure 7 For along Figure 1 Cross-sectional view obtained along line VII-VII.

[0043] Figure 8 is a perspective view of a guide bracket applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0044] Fig. 9 It is a partial projection view of a guide bracket applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0045] Fig.10 A perspective view illustrating an inner wheel and a cam unit applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0046] Fig.11 An exploded perspective view illustrating an inner wheel and a cam unit applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0047] Fig.12 It is a perspective view of an inner wheel of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0048] Fig.13 is a sectional view of an inner wheel of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0049] Fig.14 , Fig.15 and Fig.16 A schematic diagram illustrating operation of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0050] Fig.17A and Fig. 17B Schematic diagram illustrating a cam groove of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0051] Fig.18A , Fig.18B and Fig.18C Graphs showing valve characteristics of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0052] It should be understood that the accompanying drawings are not drawn to scale, but are only appropriately simplified drawings for illustrating various features of the basic principles of the present invention. The specific design features of the present invention disclosed herein include, for example, specific dimensions, directions, positions and shapes that will be determined in part by the specific environment in which they are to be applied and used.

[0053] In the figures, like reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0054] Reference will now be made in detail to various embodiments of the present invention, examples of which are illustrated in the accompanying drawings and described below. Although the present invention will be described in conjunction with exemplary embodiments of the present invention, it should be understood that this specification is not intended to limit the present invention to those exemplary embodiments. In addition, the present invention is intended to cover not only the exemplary embodiments of the present invention, but also various alternative embodiments, modified embodiments, equivalent embodiments or other embodiments, which are included in the spirit and scope of the present invention as defined by the appended claims.

[0055] In the following detailed description, only certain exemplary embodiments of the present invention have been shown and described, simply by way of illustration.

[0056] As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

[0057] Components denoted by the same reference numerals throughout the specification represent the same constituent elements.

[0058] In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity.

[0059] Throughout the specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprising” or “including”, will be understood to imply the inclusion of stated elements but not the exclusion of any other elements.

[0060] Hereinafter, various exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0061] Figure 1 is a perspective view of an engine provided with a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention, Figure 2 is a side view of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0062] Figure 3 is an exploded perspective view of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention, Figure 4 It is a partial perspective view of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0063] Figure 5 For along Figure 1 The cross-sectional view obtained along the line V-V, Figure 6is a perspective view of a wheel cover applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention, Figure 7 For along Figure 1 Cross-sectional view obtained along line VII-VII.

[0064] refer to Figures 1 to 7 , an engine 1 according to various exemplary embodiments of the present invention includes a cylinder head 3 , an engine block 5 , and a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention mounted on the cylinder head 3 .

[0065] exist Figure 4 , cylinders 201, 202, 203, and 204 are formed at the engine, but are not limited thereto.

[0066] The continuously variable valve opening duration device according to various exemplary embodiments of the present invention may include: a camshaft 30, a cam unit 70, a guide bracket 130, an inner wheel 80, a wheel cover 90, a worm gear 50, a control shaft 102, and an upper bushing 170, wherein a cam 71 is formed on the cam unit 70 and the camshaft 30 is inserted into the cam unit 70; the guide bracket 130 is formed with an upper guide boss 131; the inner wheel 80 is configured to transmit the rotation of the camshaft 30 to the cam unit 70; and the inner wheel 80 is configured to transmit the rotation of the camshaft 30 to the cam unit 70. The wheel 80 is rotatably inserted into the wheel cover 90, a guide thread 92 is formed on the wheel cover 90, and a guide shaft 91 is formed to be movably inserted into the upper guide boss 131; an internal thread 52 configured to be combined with the guide thread 92 is formed in the worm wheel 50, and an external thread 54 is formed on the worm wheel 50; a control worm 104 configured to be combined with the external thread 54 is formed on the control shaft 102; the upper bushing 170 is installed at the lower part of the upper guide boss 131 to support the guide shaft 91.

[0067] Camshaft 30 may be an intake camshaft or an exhaust camshaft.

[0068] A control shaft hole 132 supporting the control shaft 102 is formed on the guide bracket 130 , and a control shaft bearing 160 is installed on the control shaft hole 132 to support the rotation of the control shaft 102 .

[0069] The thrust bearing 150 is installed on the guide boss 131 to support the worm wheel 50 , and as shown in the drawings, the thrust bearing 150 may be installed above and below the worm wheel 50 , respectively.

[0070] The worm cover 152 may be coupled to the guide bracket 130 to support the thrust bearing 150. For example, the worm cover 152 may be coupled to the guide bracket 130 by caulking.

[0071] refer to Figure 5, the internal thread 52 and the guide thread 92 of the worm wheel 50 may be trapezoidal threads. Therefore, the rotation of the control shaft 102 is transmitted to the worm wheel 50, so that the vertical movement of the wheel cover 90 can be smoothly controlled.

[0072] The thrust bearing 150 allows the worm wheel 50 to rotate smoothly, and the worm cover 152 fixes the position of the worm wheel 50 .

[0073] Therefore, the worm wheel 50 is installed at a fixed position of the guide bracket 130 , and the wheel cover 90 can smoothly move in the up and down directions of the drawing along with the rotation of the worm wheel 50 .

[0074] A lower guide boss 133 is formed at the guide bracket 130, and a guide rod 94 inserted into the lower guide boss 133 is formed at the wheel cover 90 to guide the movement of the wheel cover 90. The guide rod 94 guides the movement of the wheel cover 90 and prevents the wheel cover 90 from vibrating.

[0075] A lower bushing 172 supporting the guide rod 94 may be installed on a lower portion of the lower guide boss 133 .

[0076] Bushings 170 and 172 are applied between the wheel cover 90 and the guide bracket 130 to prevent shaking or vibration and wear of the wheel cover 90 and to enhance strength. For example, the wheel cover 90 and the guide bracket 130 are formed of aluminum material, and the upper bushing 170 and the lower bushing 172 are formed of steel material to stably support the movement of the wheel cover 90 and reduce the thickness of the upper guide boss 131 and the lower guide boss 133.

[0077] The center portion B of the inner wheel 80 may be offset from an imaginary line A connecting the upper guide boss 131 and the lower guide boss 133 .

[0078] The camshaft 30 and the control shaft 102 may be mounted on the virtual vertical line S. Therefore, when combined with the cam cover with bolts, tool interference may be prevented.

[0079] Here, the phase of the virtual vertical line S does not mean that it is on a completely vertical line, but is a real vertical line (substantially vertical) phase, which means a configuration configured to minimize interference when working by a tool.

[0080] The center portion B of the inner wheel 80 deviates (Δ) from the imaginary line A connecting the upper guide boss 131 and the lower guide boss 133, so that the camshaft 30 and the control shaft 102 can be installed on the virtual vertical line S even if a slight inclination is provided to the valve opening duration device.

[0081] In an exemplary embodiment of the present invention, the imaginary line A is aligned along the central axis of the upper guide boss 131 and the central axis of the lower guide boss 133 .

[0082] The continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention may further include an insert 180 located between the wheel cover 90 and the guide bracket 130 .

[0083] The insert 180 may be fixed to the wheel housing 90 or the guide bracket 130 .

[0084] For example, the fixing hole 98 may be formed at the wheel cover 90, the insertion protrusion 182 may be formed at the inner side of the insert 180, and the insertion protrusion 182 may be coupled to the fixing hole 98. Conversely, a hole is formed in the guide bracket 130, and the insertion protrusion 184 is formed at the outer side of the insert 180, so that the insert 180 can be coupled to the guide bracket 130.

[0085] In addition, the insert 180 may be connected to one of the wheel cover 90 and the guide bracket 130 by bolts, fitting, or may be bonded and fixed.

[0086] The insert 180 may be formed of a plastic material. When the wheel cover 90 and the guide bracket 130 made of a metal material contact each other, noise and vibration may be generated. However, the insert 180 made of a plastic material is located between the wheel cover 90 and the guide bracket 130 to play a vibration reduction role, thereby suppressing noise and vibration. For example, the insert 180 may be formed of a wear-resistant engineering plastic such as PA66, but is not limited thereto.

[0087] The cross section of the insert 180 is formed in a “U” shape. Therefore, the insert 180 surrounds the wheel cover 90 and prevents the insert 180 from being separated, and the wheel cover 90 can be prevented from rotating around the upper guide boss 131 and the lower guide boss 133.

[0088] The wheel cover 90 has an upper stopper 95 and a lower stopper 96 that contact the guide bracket 130 to restrict movement of the wheel cover 90 .

[0089] Figure 8 is a perspective view of a guide bracket applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0090] refer to Figure 8 A step surface 134 that prevents the wheel cover 90 from rotating is formed at the guide bracket 130 .

[0091] In the guide bracket 130, an upper guide boss 131 and a lower guide boss 133 are formed so that the wheel cover 90 rotates during operation of the instrument, which may cause uneven wear.

[0092] According to various exemplary embodiments of the present invention, a stepped surface 134 is formed on the guide bracket 130 , particularly, on a boss, for coupling with a bolt on a side surface, thereby reducing the number of components and preventing the wheel cover 90 from rotating.

[0093] Fig. 9 It is a partial projection view of a guide bracket applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0094] refer to Fig. 9 A bracket oil hole 136 that supplies lubricating oil to the worm gear 50 may be formed in the guide bracket 130 .

[0095] In various exemplary embodiments of the present invention, the control shaft bearing 160 and the worm cover 152 form a single chamber, and oil is supplied to the worm wheel 50 through the bracket oil hole 136. It is possible to minimize oil pressure loss and provide oil suitable for each portion.

[0096] Fig.10 2 is a perspective view showing an inner wheel and a cam unit applied to a continuously variable valve opening duration device according to various exemplary embodiments of the present invention, Fig.11 An exploded perspective view illustrating an inner wheel and a cam unit applied to a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0097] refer to Figures 1 to 11 , a first sliding hole 86 and a second sliding hole 88 are formed at the inner wheel 80 , and a cam groove 74 is formed at the cam unit 70 .

[0098] The continuously variable valve opening duration device further includes: a roller wheel 60 and a roller cam 82 , wherein the roller wheel 60 is connected to the camshaft 30 and is rotatably inserted into the first sliding hole 86 ; the roller cam 82 is slidably inserted into the cam groove 74 and is rotatably inserted into the second sliding hole 88 .

[0099] The roller cam 82 includes a roller cam body 82 a slidably inserted into the cam groove 74 and a cam head 82 b rotatably inserted into the second sliding hole 88 .

[0100] A protrusion 82 c is formed at the roller cam 82 for preventing the roller cam 82 from being separated from the inner wheel 80 in the longitudinal direction of the cam shaft 30 .

[0101] The roller 60 includes a wheel body 62 and a wheel head 64 . The wheel body 62 is slidably connected to the cam shaft 30 . The wheel head 64 is rotatably inserted into the first sliding hole 86 . The wheel body 62 and the wheel head 64 may be integrally formed.

[0102] A camshaft hole 34 is formed at the camshaft 30 , the wheel body 62 of the roller wheel 60 is movably inserted into the camshaft hole 34 , and the wheel head 64 is rotatably inserted into the first slide hole 86 .

[0103] The camshaft oil hole 32 is formed in the camshaft 30 along the longitudinal direction of the camshaft 30, the wheel body oil hole 66 communicating with the camshaft oil hole 32 is formed at the wheel body 62 of the roller 60, and the oil groove 68 (refer to Fig.14 ) is formed at the wheel head 64 of the roller 60.

[0104] The lubricant supplied to the camshaft oil hole 32 may be supplied to the inner wheel 80 through the wheel body oil hole 66 , the communication hole 69 , and the oil groove 68 .

[0105] Fig.12 is a perspective view of an inner wheel of a continuously variable valve opening duration device according to various exemplary embodiments of the present invention, Fig.13 is a sectional view of an inner wheel of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0106] refer to Figure 2 , Fig.12 and Fig.13 The cam unit 70 includes a first cam portion 70a and a second cam portion 70b respectively arranged corresponding to the cylinder and the adjacent cylinder (for example, the first cylinder 201 and the adjacent second cylinder 202), and the inner wheel 80 includes a first inner wheel 80a and a second inner wheel 80b respectively transmitting the rotation of the camshaft 30 to the first cam portion 70a and the second cam portion 70b.

[0107] The continuously variable valve opening duration device further includes a first bearing 140 and a second bearing 141 which are internally arranged in the wheel housing 90 for supporting the first inner wheel 80a and the second inner wheel 80b.

[0108] The first bearing 140 and the second bearing 141 may be needle bearings, the first inner wheel 80a and the second inner wheel 80b are disposed internally in one wheel cover 90, and the first bearing 140 and the second bearing 141 may rotatably support the first inner wheel 80a and the second inner wheel 80b.

[0109] Since the first inner wheel 80a and the second inner wheel 80b can be internally arranged in one wheel cover 90, the number of components can be reduced, so that productivity and manufacturing economy can be improved.

[0110] The first inner wheel 80a and the second inner wheel 80b in the wheel cover 90 may be rotatably connected to each other. For example, the first inner wheel connecting portion 84 and the second inner wheel connecting portion 85 are formed at the first inner wheel 80a and the second inner wheel 80b, respectively, and the first inner wheel connecting portion 84 and the second inner wheel connecting portion 85 are connected to each other.

[0111] In the drawings, the first inner wheel connecting portion 84 and the second inner wheel connecting portion 85 are formed in convex and concave shapes, but are not limited thereto. The first inner wheel 80a and the second inner wheel 80b are rotatably connected to each other through a variable connection structure.

[0112] In the case where the first inner wheel 80a and the second inner wheel 80b are connected, looseness or vibration caused by manufacturing tolerances of bearings, inner wheels, lifters, etc. can be reduced.

[0113] Two cams 71 and 72 may be formed in pairs on the first cam portion 70 a and the second cam portion 70 b , and a cam cover connecting portion 76 is formed between the pair of cams 71 and 72 of each of the first cam portion 70 a and the second cam portion 70 b .

[0114] Cams 71 and 72 rotate and open valve 200 .

[0115] Fig.14 , Fig.15 and Fig.16 A schematic diagram illustrating operation of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0116] like Fig.14 As shown, when the rotation centers of the camshaft 30 and the cam unit 70 coincide, the cams 71 and 72 rotate at the same phase angle as the camshaft 30 .

[0117] According to the operating state of the engine, the ECU (Engine Control Unit or Electronic Control Unit) sends a control signal to the control portion 100, which then controls the motor 106 to rotate the control shaft 102 (see Figure 2 ).

[0118] refer to Figure 5 , Fig.15 and Fig.16 The control worm 104 coupled with the external thread 54 rotates the worm wheel 50 , and since the internal thread 52 formed at the worm wheel 50 is coupled with the guide thread 130 , the worm wheel 50 moves along the guide thread 130 .

[0119] That is, the worm wheel 50 is rotated by the rotation of the control shaft 102 , and the relative position of the wheel cover 90 with respect to the camshaft 30 is changed.

[0120] When the position of the wheel cover 90 moves up and down relative to the rotation center portion of the cam shaft 30, the relative rotation speeds of the cams 71 and 72 relative to the rotation speed of the cam shaft 30 change.

[0121] When the roller wheel (i.e., sliding pin) 60 rotates together with the camshaft 30, the pin body 62 is slidable in the camshaft hole 34, the pin head 64 is rotatable in the first sliding hole 86, and the roller cam 82 is rotatable in the second sliding hole 88 and slidable in the cam groove 74. Therefore, the relative rotation speed of the cams 71 and 72 relative to the rotation speed of the camshaft 30 changes.

[0122] Fig.17A and Fig. 17B Schematic diagram showing a cam slot of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention, Fig.18A , Fig.18B and Fig.18C Graphs showing valve characteristics of a continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention.

[0123] like Fig.17A and Fig. 17B As shown, the cam groove 74 may be formed to lag behind the position of the cam 71 or 72 (refer to Fig.17A ), or the cam groove 74 may be formed to be earlier than the position of the cam 71 or 72 (refer to Fig. 17B ), or the cam groove 74 can be formed to be in the same phase as the cam 71 or 72. With the above scheme, different valve characteristics can be achieved.

[0124] Although the maximum lift of the valve 200 is constant, the rotation speed of the cams 71 and 72 relative to the rotation speed of the camshaft 30 changes according to the relative position of the wheel cover 90, thereby changing the closing and opening time of the valve 200. That is, the opening duration of the valve 200 changes.

[0125] According to the relative position of the cam groove 74, the installation angle of the valve 200, etc., the opening and closing time of the valve can be changed at the same time, such as Fig.18A shown.

[0126] When the opening time of the valve 200 is constant, the closing time of the valve 200 can be delayed or advanced, such as Fig.18B shown.

[0127] When the closing time of the valve 200 is constant, the opening time of the valve 200 can be delayed or advanced, such as Fig.18C shown.

[0128] As described above, the continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention can realize various valve opening durations with a simple configuration.

[0129] The continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention may be downsized, so that the overall height of the valve train may be reduced.

[0130] Since the continuously variable valve opening duration device can be applied to an existing engine without much modification, productivity can be improved and production costs can be reduced.

[0131] The continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention may reduce the number of components and reduce vibration and noise by applying a worm gear.

[0132] In various exemplary embodiments of the present invention, the continuously variable valve opening duration apparatus is configured to prevent wear and enhance strength by applying a bushing between a wheel cover and a guide bracket.

[0133] The continuously variable valve opening duration apparatus according to various exemplary embodiments of the present invention prevents the wheel cover from rotating and reduces noise and vibration by applying an insert between the wheel cover and a guide bracket.

[0134] For convenience of explanation and precise definition of the appended claims, the terms "up", "down", "inside", "outside", "above", "below", "upward", "downward", "front", "back", "inside", "outside", "inward", "outward", "inner", "external", "inside", "outside", "inner", "outer", "forward" and "rearward" are used to describe the features of the exemplary embodiments with reference to the positions of such features as shown in the drawings. It should be further understood that the term "connect" or its derivatives refer to both direct and indirect connections.

[0135] The foregoing descriptions of specific exemplary embodiments of the present invention are for the purpose of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise embodiments disclosed, and it is apparent that various modifications and variations may be made in accordance with the foregoing teachings. The exemplary embodiments are selected and described in order to explain the specific principles of the present invention and their practical applications, so that other persons skilled in the art can implement and utilize the various exemplary embodiments of the present invention and their various alternatives and modifications. The scope of the present invention is intended to be limited by the appended claims and their equivalents.

Claims

1. A valve opening duration control device, include: Camshaft; a cam unit on which a cam is formed and into which the cam shaft is inserted; a guide bracket including an upper guide boss; an inner wheel configured to transmit the rotation of the camshaft to the cam unit; a wheel cover into which the inner wheel is rotatably inserted, wherein a guide thread is formed on a portion of the wheel cover, and the wheel cover includes a guide shaft that is movably inserted into the upper guide boss; a worm wheel, in which an internal thread combined with the guide thread is formed, and on which an external thread is formed; a control shaft including a control worm coupled to the external thread; an upper bushing mounted on a lower portion of the upper guide boss to support the guide shaft; a thrust bearing mounted on the upper guide boss to support the worm gear; a first sliding hole and a second sliding hole, which are respectively formed at the inner wheel; a cam groove formed at the cam unit; a roller slidably connected to the cam shaft and rotatably inserted into the first sliding hole; and A roller cam is slidably inserted into the cam groove and rotatably inserted into the second slide hole.

2. The valve opening duration control device according to claim 1, in, The guide bracket further includes a lower guide boss; The wheel cover includes a guide rod inserted into the lower guide boss to guide movement of the wheel cover. 3 . The valve opening duration control device according to claim 2 , further comprising a lower bushing installed on a lower portion of the lower guide boss to support the guide rod.

4. The valve opening duration control device according to claim 2, in, A central portion of the inner wheel is aligned to be offset from an imaginary line connecting the upper guide boss and the lower guide boss. 5 . The valve opening duration control device according to claim 1 , further comprising an insert installed between the wheel cover and the guide bracket.

6. The valve opening duration control device according to claim 5, in, The insert is fixed to one of the wheel housing and the guide bracket.

7. The valve opening duration control device according to claim 5, in, The insert is made of plastic material.

8. The valve opening duration control device according to claim 5, in, The cross section of the insert is formed in a "U" shape.

9. The valve opening duration control device according to claim 1, in, A control shaft hole supporting the control shaft is formed at the guide bracket. 10 . The valve opening duration control device according to claim 9 , further comprising a control shaft bearing installed on the control shaft hole to rotatably support the control shaft. 11 . The valve opening duration control device of claim 1 , further comprising a step surface formed at the guide bracket to prevent the wheel cover from rotating.

12. The valve opening duration control device according to claim 1, in, The roller cam comprises: a roller cam body that can be slidably inserted into the cam groove; a cam head rotatably inserted into the second sliding hole; and A protrusion is formed in the longitudinal direction of the cam shaft and is configured to prevent the roller cam from being removed from the inner wheel.

13. The valve opening duration control device according to claim 12, in, The roller comprises: a wheel body slidably connected to the camshaft; and The wheel head is rotatably inserted into the first sliding hole.

14. The valve opening duration control device according to claim 13, further comprising: include: a camshaft oil hole formed in the camshaft along a longitudinal direction of the camshaft; a wheel body oil hole formed at the wheel body of the roller wheel and in fluid communication with the camshaft oil hole; as well as An oil groove is formed at the wheel head of the roller and is in fluid communication with the wheel body oil hole.

15. The valve opening duration control device according to claim 1, in, The cam unit includes a first cam portion and a second cam portion respectively installed corresponding to the cylinder and an adjacent cylinder; The inner wheels include a first inner wheel and a second inner wheel that transmit the rotation of the cam shaft to the first cam portion and the second cam portion, respectively.

16. The valve opening duration control device according to claim 15, in, The first inner wheel and the second inner wheel are rotatably connected to each other. 17 . The valve opening duration control device according to claim 15 , further comprising a first bearing and a second bearing, the first bearing and the second bearing being internally mounted in the wheel cover and supporting the first inner wheel and the second inner wheel, respectively.

18. An engine equipped with the valve opening duration control device according to claim 1.

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