The disclosure of Japanese Patent Application No. 2007-151529 filed on Jun. 7, 2007 including the specification, drawings and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The invention relates generally to an electromagnetically-driven valve, and more specifically to an electromagnetically-driven valve that collectively opens or closes multiple valves provided in an internal combustion engine.
2. Description of the Related Art
For example, the specification of U.S. Pat. No. 6,467,441 describes art related to an existing electromagnetically-driven valve, more specifically, an electromagnetic actuator that actuates a valve of an internal combustion engine using electromagnetic force and elastic force of a spring in combination. The electromagnetic actuator described in the specification of U.S. Pat. No. 6,467,441 includes a valve that has a stem, and a pivot arm. The pivot arm has a first end portion that is pivotally supported by a support frame, and a second end portion that contacts a tip of the stem. Electromagnets each include a core and a coil wound around the core are, are arranged above and below the pivot arm.
The electromagnetic actuator further includes a torsion bar that is fitted to the first end portion of the pivot arm and that applies force to the valve to open the valve, and a spiral spring that is arranged around the outer periphery of the stem and that applies force to the valve to close the valve. The pivot arm is alternately attracted to the cores of the electromagnets arranged above and below the pivot arm on the basis of the elastic force of the torsion bar and the elastic force of the spiral spring.
Electromagnetically-driven valves that are structured in a fashion similar to that described above are described in Japanese Patent Application Publication No. 2007-23889 (JP-A-2007-23889), Japanese Patent Application Publication No. 2007-32436 (JP-A-2007-32436), the specification of German Patent Laid-Open Publication No. 10025491, the specification of U.S. Pat. No. 7,088,209, the specification of U.S. Pat. No. 6,571,823, and the specification of U.S. Pat. No. 6,481,396.
The electromagnetically-driven valve described in the specification of U.S. Pat. No. 6,467,441 is called a pivot-type electromagnetically-driven valve. The pivot-type electromagnetically-driven valve converts pivot motion of the pivot arm into linear motion, and transfers the linear motion to the valve. In this type of electromagnetically-driven valve, as the pivot arm pivots about the first end portion, a displacement in the direction that intersects with the direction in which the valve moves is caused at the second end portion of the pivot arm. In this case, if lubrication between the second end portion and the stem is inadequate, the valve is not driven smoothly. This may increase the amount of electric power that is consumed by the electromagnetically driven valve or shorten its useful life.
The invention provides an electromagnetically-driven valve in which a valve is driven smoothly.
An aspect of the invention relates to an electromagnetically-driven valve that includes: a first valve and a second valve that are provided in an internal combustion engine, and that are arranged side by side; a disk that pivots using applied electromagnetic force to reciprocate the first valve and the second valve in a predetermined direction; and a connection member that connects the first valve with the second valve. The connection member includes an input portion into which pivot motion of the disk is input. The pivot motion of the disk causes a displacement between the input portion and the disk relative in a direction that intersects with the predetermined direction. An oil passage is formed within the connection member, and allows oil to be supplied to the input portion.
In the thus structured electromagnetically-driven valve, it is possible to supply the oil to the input portion through the oil passage formed within the connection member. Thus, it is possible to reliably lubricate the input portion that is displaced relative to the disk, thereby smoothly driving the first valve and the second valve.
In the first aspect of the invention, the input portion may be a bearing that is arranged so as to contact the disk. In the thus structured electromagnetically-driven valve, it is possible to supply the oil to the bearing through the oil passage.
In the first aspect of the invention, the connection member may include an oil bath portion in which the oil that is supplied through the oil passage is stored and the bearing is disposed. In the thus structured electromagnetically-driven valve, it is possible to reliably supply the oil to the bearing.
In the first aspect of the invention, the bearing may include an outer race, and multiple rotating elements that are arranged inside of the outer race and that are aligned in a circumferential direction of the outer race. The outer race may have an outer periphery that contacts the disk, an inner periphery that contacts the rotating elements, and a hole that extends from the outer periphery to the inner periphery. In the thus structured electromagnetically-driven valve, it is possible to more reliably supply the oil to the rotating elements that are arranged inside the outer race.
In the first aspect of the invention, the connection member may include a first fitting portion and a second fitting portion in which the first valve and the second valve are fitted, respectively. The oil passage may be formed so as to communicate with at least one of the first fitting portion and the second fitting portion. In the thus structured electromagnetically-driven valve, it is possible to supply the oil to at least one of the first fitting portion and the second fitting portion. Thus, it is possible to reliably lubricate at least one of the first fitting portion and the second fitting portion, thereby driving the first valve and the second valve more smoothly.
As described above, according to the invention, it is possible to provide the electromagnetically-driven valve in which the valve is driven more smoothly.
The foregoing and further features and advantages of the invention will become apparent from the following description of an example embodiment with reference to the accompanying drawings, wherein the same or corresponding portions will be denoted by the same reference numerals and wherein:
Hereafter, an embodiment of the invention will be described with reference to the accompanying drawings. Note that, the same or corresponding portions will be denoted by the same reference numerals in the drawings.
The type of an internal combustion engine in which the electromagnetically-driven valve 10 is provided is not particularly limited. For example, the electromagnetically-driven valve 10 may be provided in a diesel engine. The internal combustion engine may be a single-cylinder engine. The layout of the cylinders 200 is not particularly limited. The electromagnetically-driven valve 10 may be provided in, for example, a V engine, a horizontally opposed engine, or a W engine.
Each cylinder of the gasoline engine 60 is provided with intake valves 14p and 14q and exhaust valves 15p and 15q. At each cylinder, the intake valve 14p and the intake valve 14q are arranged side by side, and the exhaust valve 15p and the exhaust valve 15q are arranged side by side. The electromagnetically-driven valve 10 collectively opens or closes the intake valve 14p and the intake valve 14q of each cylinder of the gasoline engine 60. Similarly, the electromagnetically-driven valve 10 collectively opens or closes the exhaust valve 15p and the exhaust valve 15q of each cylinder of the gasoline engine 60.
The electromagnetically-driven valve 10 may be structured so as to collectively open or close three or more intake valves or exhaust valves.
As shown in
The intake valve 14p and the intake valve 14q include a stem 11p and a stem 11q, respectively. The stem 11p and the stem 11q extend in parallel to each other. The intake valve 14p and the intake valve 14q reciprocate in the direction in which the stems 11p and 11q extend (direction shown by arrows 101) in accordance with the pivot motion of the disk 21.
The intake valves 14p and 14q are provided in a cylinder head 18. Intake ports 16 are formed within the cylinder head 18. Valve seats 19 are provided at positions at which the intake ports 16 are communicated with a combustion chamber 17. The intake valve 14p and the intake valve 14q include bell portions 12 that are fitted to the tips of the stem lip and the stem 11q. In accordance with the reciprocation of the intake valves 14p and 14q, the bell portions 12 contact the valve seats 19 or move away from the valve seats 19, whereby the intake ports 16 close or open.
The electromagnetically-driven valve 10 includes a connection member 50. The connection member 50 connects the intake valve 14p and the intake valve 14q to each other, and transfers the pivot motion of the disk 21 that is caused by the electromagnetic force to the intake valves 14p and 14q. The connection member 50 connects the intake valves 14p and 14q to the disk 21.
In the embodiment of the invention, the connection member 50 is formed of a valve plate 31 and an intermediate stem 32. The valve plate 31 and the intermediate stem 32 are connected to each other. The valve plate 31 extends from the intake valve 14p toward the intake valve 14q. The valve plate 31 connects the intake valve 14p and the intake valve 14q with each other. The intermediate stem 32 connects the disk 21 and the valve plate 31 to each other. The intermediate stem 32 includes an input portion 32c to which the pivot motion of the disk 21 is transferred. The driving force generated by the electromagnetic force is transferred from the disk 21 to the valve plate 31 through the intermediate stem 32.
The valve plate 31 and the intermediate stem 32 of the connection member 50 need not be separate members. The valve plate 31 and the intermediate stem 32 may be integrally formed.
The electromagnetically-driven valve 10 includes guide members 41 that guide the stems 11p and 11q so that the stems 11p and 11q slide in their axial direction. The electromagnetically-driven valve 10 includes a guide member 42 that guides the connection member 50 so that the connection member 50 slides in its axial direction. The guide member 42 guides the intermediate stem 32 of the connection member 50. The guide members 41 and the guide member 42 are made of metal, for example, stainless, so that these guide members endure high-speed slide over the stems. With this structure, the connection member 50 together with the intake valves 14p and 14q reciprocates in the direction indicated by the arrows 101.
Lower springs 43, which serve as first spring members, are supported on the peripheries of the stems 11p and 11q by lower retainers 44 having a brimmed shape. The lower springs 43 are formed of coil springs. The lower springs 43 apply elastic forces for moving the stems 11p and 11q upward to the intake valves 14p and 14q.
A support base 48 is fixed onto the top face of the cylinder head 18. The support base 48 supports the electromagnets 51m and 51n. The electromagnet 51m is arranged above the disk 21, and the electromagnet 51n is arranged below the disk 21.
The electromagnet 51m and the electromagnet 51n are the same in shape. The shape of the electromagnet 51n will be described below. The electromagnet 51n includes a coil 53 and a core 52. The coil 53 is wound around the core 52.
The core 52 is made of magnetic material. In the embodiment of the invention, the core 52 is formed of multiple electromagnetic steel plates that are stacked on top of each other. The core 52 may be made of magnetic material other than electromagnetic steel plates, for example, a green compact made of magnetic power. The coil 53 of the electromagnet 51m and the coil 53 of the electromagnet 51n may be made of a continuous single coil wire, or made of separate coil wires.
The support base 48 supports the disk 21. The disk 21 is made of magnetic material. The disk 21 is formed of a bulk material to maintain a sufficient level of strength. The disk 21 includes a support portion 23 and a connection portion 22. The central axis 25 is defined in the support portion 23. The disk 21 extends from the support portion 23 toward the connection portion 22 in the direction that intersects with the intermediate stem 32.
A through-hole 24 is formed in the support portion 23. A torsion bar 30, which serves as a second spring member, is press-fitted into the through-hole 24. The torsion bar 30 extends in the axial direction of the central axis 25. The support portion 23 is pivotally supported by the support base 48 via the torsion bar 30.
The torsion bar 30 applies elastic force for causing the disk 21 to pivot counterclockwise about the central axis 25 to the disk 21. That is, the torsion bar 30 applies elastic force for moving the stems 11p and 11q downward to the intake valves 14p and 14q via the valve plate 31. When the electromagnetic force is not applied to the disk 21, the disk 21 is kept at the middle portion between the valve open position and the valve closed position due to the elastic forces of the lower springs 43 and the torsion bar 30. Contact between the input portion 32c and the connection portion 22 is maintained by the elastic forces of the lower springs 43 and the torsion bar 30.
When an electric current is supplied to the coil 53 of the electromagnet 51m, a magnetic flux flow is formed so as to pass through the core 52 of the electromagnet 51m and the disk 21. Thus, the electromagnet 51m generates electromagnetic force that attracts the disk 21 to the electromagnet 51m. When an electric current is supplied to the coil 53 of the electromagnet 51n, a magnetic flux flow is formed so as to pass through the core 52 of the electromagnet 51n and the disk 21. Thus, the electromagnet 51n generates electromagnetic force that attracts the disk 21 to the electromagnet 51n.
The disk 21 is attracted alternately to the electromagnet 51m and the electromagnet 51n by the electromagnetic force generated by the electromagnet 51m and the elastic force of the lower spring 43, and the electromagnetic force generated by the electromagnet 51n and the elastic force of the torsion bar 30. As a result, the disk 21 pivots about the central axis 25. When the disk 21 is attracted to the electromagnet 51m, the stems 11p and 11q move upward, and the intake valves 14p and 14q are brought to the valve closed positions. When the disk 21 is attracted to the electromagnet 51n, the steps 11p and 11q move downward, and the intake valves 14p and 14q are brought to the valve open positions.
When the disk 21 pivots about the support portion 23, the connection portion 22 pivots about the central axis 25 while making an arc-shaped trail. More specifically, when the disk 21 pivots from the position, at which the disk 21 is fully pivoted so that the valve is closed, toward the intermediate position, the connection portion 22 moves downward while moving in the direction in which the connection portion 22 moves away from the central axis 25 when viewed from above. When the disk 21 crosses the intermediate position and pivots toward the position, at which the disk is fully pivoted so that the valve is open, the connection portion 22 moves downward while moving in the direction in which the connection portion 22 comes closer to the central axis 25 when viewed from above. The connection member 50 together with the intake valves 14p and 14q reciprocates in the direction indicated by the arrows 101 while being supported by the guide member 42.
Therefore, the pivot motion of the disk 21 causes a displacement between the disk 21 and the connection member 50 in the direction that intersects with the direction in which the intake valves 14p and 14q reciprocate. In the embodiment of the invention, the needle bearing 81 rotates in the forward direction and the reverse direction while contacting the disk 21, whereby the relative displacement is absorbed.
The connection member 50 has an oil passage 66. The oil passage 66 is formed within the connection member 50 and opens near the needle bearing 81. The oil flows through the oil passage 66 and is supplied to the needle bearing 81.
The connection member 50 includes a pan-shaped oil bath portion 61. The needle bearing 81 is arranged in the oil bath portion 61. The oil passage 66 leads to the oil bath portion 61. The oil that is supplied through the oil passage 66 is stored in the oil bath portion 61. The needle bearing 81 is partially immersed in the oil that is stored in the oil bath portion 61. The oil that is stored in the oil bath portion 61 is raised by the rotation of the needle bearing 81, and supplied to the portion at which the needle bearing 81 and the disk 21 contact each other. In this way, it is possible to reliably lubricate and cool the needle bearing 81.
The valve plate 31 is slidably fitted in the oil introduction chamber 73. The valve plate 31 together with the intake valves 14p and 14q reciprocates while moving within the oil introduction chamber 73. An O-ring 72, which serves as a seal member, is arranged between the valve plate 31 and the inner wall of the oil introduction chamber 73. With this structure, it is possible to supply the oil into the oil passage 66 while preventing leakage of oil from the oil introduction chamber 73.
As shown in
In the embodiment of the invention, the distance between the hole 36 and the hole 37 is determined based on the distance between the intake valve 14p and the intake valve 14q. However, it is difficult to accurately match the distance between the holes 36 and 37 with the distance between the intake valves 14p and 14q due to variation in the processing accuracy of the components and assembly error. Therefore, clearances are formed between the inner wall of the hole 36 and the stem 11p and between the inner wall of the hole 37 and the stem 11q. In this case, in accordance with the reciprocation of the intake valve 14p and the intake valve 14q, the inner wall of the hole 36 and the stem 11p, and the inner wall of the hole 37 and the stem 11q grind against each other, which may generate metal powder. However, if the oil is supplied to the fitting portions 34 and 35 through the oil passage 66, it is possible to appropriately lubricate the fitting portions.
In the embodiment of the invention, clearances are formed in the fitting portion 34 and the fitting portion 35. Alternatively, a clearance may be formed in one of the fitting portion 34 and the fitting portion 35. In this case, the oil passage 66 is formed so as to lead only to the fitting portion in which a clearance is formed. The fitting portions 34 and 35 are not limited to the ones described above. For example, shaft portions may be provided to the valve plate 31, and the shaft portions may be fitted in holes formed in the stems 11p and 11q.
The electromagnetically-driven valve 10 according to the embodiment of the invention includes: the intake valve 14p and the intake valve 14q that are provided in the gasoline engine 60, which is an internal combustion engine, that are arranged side by side, and that serve as the first valve and the second valve, respectively; the disk 21 that pivots using supplied electromagnetic force and that reciprocates the intake valve 14p and the intake valve 14q in the predetermined direction (direction indicated by the arrows 101); and the connection member 50 that connects the intake valve 14p with the intake valve 14q. The connection member 50 includes the needle bearing 81 that serves as the input portion into which the pivot motion of the disk 21 is input. The pivot motion of the disk 21 causes a displacement between the needle bearing 81 and the disk 21 in the direction that intersects with the predetermined direction. The oil passage 66 is formed in the connection member 50 and supplies the oil to the needle bearing 81.
In the thus structured electromagnetically-driven valve 10 according to the embodiment of the invention, the needle bearing 81 is reliably lubricated with the oil that is supplied through the oil passage 66. Thus, it is possible to reduce the friction in the needle bearing 81, thereby smoothly reciprocating the intake valves 14p and 14q. As a result, it is possible to reduce the amount of electric power consumed by the electromagnetically-driven valve 10 and prolong its useful life.
An example of the method for supplying the oil to the needle bearing 81 is to form the oil passage within the disk 21. However, as described above, when the intake valves 14p and 14q are driven, a magnetic flux flow is formed in the disk 21. Therefore, formation of the oil passage in the disk 21 interrupts the magnetic flux flow. As a result, the magnetic characteristics of the disk 21 may be impaired. In addition, the disk 21 repeatedly contacts the cores 52 of the electromagnets 51m and 51n. Therefore, it is not preferable to form the oil passage in the disk 21 from the viewpoint of ensuring sufficient strength. In contrast, according to the embodiment of the invention, the oil passage 66 is formed in the connection member 50. Therefore, reduction in the magnetic characteristics and the strength of the disk 21 are avoided.
Hereafter, various modifications of the electromagnetically-driven valve 10 according to the embodiment of the invention will be described. The structure that is common between the modifications and the embodiment will not be described below.
With the structure in which at least one hole 86 that extends through the outer race 82 is formed, it is possible to reliably supply the oil to the needle pins 84. Thus, it is possible to more reliably lubricate the needle bearing 81.
The upper disk 21x and the lower disk 21y are arranged with a predetermined space left therebetween. The support portion 23 of the upper disk 21x and the support portion 23 of the lower disk 21y have a central axis 25x and a central axis 25y, respectively. The upper disk 21x and the lower disk 21y are pivotable about the central axis 25x and the central axis 25y, respectively. The electromagnet 51 is placed between the upper disk 21x and the lower disk 21y.
Each of the connection portions 22 of the upper disk 21x and the lower disk 21y includes a pin 91. Oblong holes 92 are formed in the intermediate stem 32 and serve as input portions. When the pins 91 are fitted in the oblong holes 92, the upper disk 21x and the lower disk 21y are coupled to the intermediate stem 32. When the intake valves 14p and 14q are driven, the pins 91 reciprocate within the oblong holes 92 in the longitudinal direction of the oblong holes 92. Thus, it is possible to absorb a relative displacement between the upper disk 21x/lower disk 21y and the connection member 50 in the direction that intersects with the direction in which the intake valves 14p and 14q reciprocate.
The oil passage 66 is formed within the connection member 50 so as to open at the inner walls of the oblong holes 92. With this structure, it is possible to reliably supply the oil through the oil passage 66 to the portions at which the inner walls of the oblong holes 92 and the pins 91 slide over each other.
The thus structured electromagnetically-driven valve produces mostly the same advantageous effects as those in the embodiment of the invention.
Thus, the embodiment of the invention that has been disclosed in the specification are to be considered in all respects as illustrative and not restrictive. The technical scope of the invention is defined by claims, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Number | Date | Country | Kind |
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2007-151529 | Jun 2007 | JP | national |