JP2008215109A - Valve spring and valve device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve spring and a valve device capable of realizing effective suppression of surging by simple structure. <P>SOLUTION: The valve device (2) is equipped with a valve stem (3), a retainer (4) disposed on one end side of the valve stem (3) and fixed thereto, and a valve spring seat (5) disposed opposing the retainer (4). The valve spring (1) is sandwiched between the retainer (4) and the valve spring seat (5). The valve spring (1) is mounted so that during a full lift, adjacent windings (1a) come in close contact with each other. The winding (1a) is coated by rubber. The wire diameter of the winding (1a) is ensured with a diameter (thickness) for enduring repeated contact of the adjacent windings (1a) considering that the adjacent windings (1a) repeatedly come into contact with each other. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement of a valve spring incorporated in a valve device constituting an intake / exhaust mechanism of an internal combustion engine.

  Conventionally, a coil spring is generally used as a valve spring for energizing an intake / exhaust valve of a piston internal combustion engine. This coil spring generates surging according to the natural frequency of the valve spring during high-speed rotation of the engine, and this surging may cause abnormal movement such as jump or bounce of the valve.

  As a valve spring for avoiding such surging, there is a proposal of Patent Document 1. In Patent Document 1, a valve that is driven back and forth via a cam and a valve spring that has a base end supported by a spring seat and is connected to the valve at the other end to bias the valve in the valve closing direction are provided on the way. In the valve spring of the internal combustion engine in which the winding is formed at a different predetermined pitch from the densely wound portion having a predetermined pitch with which adjacent windings can closely contact each other from the spring seat side of the valve spring to a predetermined position; A valve spring is disclosed that is formed in the winding of the tightly wound portion and includes a plane that is substantially orthogonal to the axial direction of the valve spring.

  Such a valve spring contacts and separates by surging, and the plane of the densely wound portion that is substantially perpendicular to the axial direction of the valve spring pushes away the oil remaining in the vicinity of the spring seat of the cylinder head, and the windings of the closely wound portion collide with each other. In addition to energy, the plane formed on the winding receives a damping force due to the oil that pushes away, so it is possible to reliably suppress surging by suppressing the resonance amplitude of the valve spring, and tight winding during steady engine operation Since the part is in close contact with the adjacent winding and does not push the oil, the driving resistance of the valve system is not increased, and the thermal efficiency of the engine can be ensured.

  Patent Document 1 also discloses a configuration in which oil is always retained on the spring seat side of the valve spring and at least a part of the tightly wound portion of the valve spring is immersed in the retained oil. Has been. In the valve spring having such a configuration, since the tightly wound portion is always immersed in oil, the resonance amplitude can be surely attenuated by the immersed oil when surging occurs, and the reliability of suppression of surging can be improved. It is disclosed that it is possible.

JP-A-8-177422

  In the valve spring disclosed in Patent Literature 1, surging due to damping force is expected to be suppressed by oil that displaces a plane formed on the winding in addition to energy with which the windings of the closely wound portions collide with each other. However, in order to increase the effect of suppressing surging by the damping force by the oil, a dipping means capable of dipping at least a part of the closely wound portion in the accumulated oil is provided. That is, in order to obtain a high surging suppression effect, not only the pitch of the valve spring itself but also a complicated process for forming the dipping means is required.

  Therefore, an object of the present invention is to provide a valve spring and a valve device that can effectively suppress surging with a simple configuration.

  In order to solve such a problem, a valve spring of the present invention is a valve spring that is sandwiched between a retainer disposed on one end side of a valve stem and a valve spring seat disposed to face the retainer. Thus, adjacent windings are in contact with each other during operation (claim 1). The valve spring is sandwiched between a retainer disposed on one end side of the valve stem and a valve spring seat disposed to face the retainer. The contact is made over the entire length (claim 2). In such a valve spring, adjacent windings come into contact each time the expansion and contraction operation is performed once, and amplification of the amplitude of vibration generated in the spring is suppressed. In particular, when the valve is lifted, the spring sandwiched between the valve spring seat and the retainer is compressed. It can be avoided.

  Such a valve spring can be configured such that adjacent windings are in contact with each other over the entire length of the spring when the valve is fully lifted (Claim 3).

  Further, in such a valve spring, the winding wire may be coated (claim 4). For example, by coating the winding forming the valve spring with rubber or the like, it is possible to reduce excessive impact when the windings come into contact with each other. Moreover, the bouncing of the windings at the time of windings contacting can also be suppressed. This further suppresses surging.

  By combining such a valve spring with a valve stem, a valve spring seat, a retainer or the like, the valve device of the present invention can be configured (claim 5).

  According to the valve spring of the present invention, the adjacent windings are brought into contact with each other, so that the valve spring is brought into contact with each other every time the expansion and contraction operation is performed, and the vibration generated in the spring is prevented. Amplification of the amplitude amount is suppressed, and surging can be suppressed.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1A and FIG. 1B are explanatory views showing a schematic configuration of a valve device 2 incorporating the valve spring 1 of this embodiment. FIG. 1A shows the valve device 2 in a closed state, and FIG. 1B shows the valve device 2 in an open state (full lift state).

  The valve device 2 includes a valve stem 3, a retainer 4 fixed on one end side of the valve stem 3, and a valve spring seat 5 disposed so as to face the retainer 4. A valve spring 1 is held between the retainer 4 and the valve spring seat 5. As a result, the valve spring 1 exerts a biasing force that moves the valve stem 3 in the valve closing direction. A valve lifter 6 is mounted on the upper end portion of the valve stem 3, and the cam 7 is disposed on the upper surface thereof.

  Here, the valve spring 1 is mounted so that the adjacent windings 1a1 and 1a2, 1a2 and 1a3,..., 1a6 and 1a7 are in contact with each other at the time of full lift shown in FIG. That is, the valve spring 1 expands and contracts depending on the position of the cam 7, but the adjacent windings have their full length when the retainer 4 is pushed down and is compressed between the retainer 4 and the valve spring seat 5. It is comprised so that it may contact over. In the valve spring 1, the wire diameter, interval, and total length of the winding 1a are defined so that such a state can be realized. Further, such a winding 1a is coated with rubber. In addition, when determining the wire diameter of the winding 1a, the diameter (thickness) which can endure repeated contact is ensured considering the adjacent winding 1a contacting repeatedly.

  Next, the operation of the valve device 2 configured as described above will be described. When the engine is operating, the bus unit 2 repeatedly displays the valve closed state shown in FIG. 1A and the valve open state (full lift state) shown in FIG. When the state of the valve spring 1 is changed between a valve open state and a valve closed state, the windings 1a come into contact with each other. In particular, the valve spring 1 at the time of full lift is in a state of being sandwiched between the retainer 4 and the valve spring seat 5 so that the windings 1a are in close contact with each other. Although it is considered that the valve spring 1 is vibrated due to various factors during its operation, the vibration is suppressed by the close contact between the windings 1a every time the valve spring 1 is in a full lift state. Surging generated in the coil spring 1 is caused by the resonance of the natural frequency of the coil spring 1 caused by various factors that act from the outside. However, the valve spring 1 of the present embodiment is subjected to the vibration extinction action every time in the full lift state, and the vibration is suppressed each time. As a result, the vibration generated in the valve spring 1 is prevented from reaching the natural frequency of the valve spring 1. Thereby, generation | occurrence | production of the surging in the valve spring 1 is suppressed.

  In the valve spring 1 in which surging is suppressed by such an action, the windings 1a are in contact with each other, but since the coating treatment with rubber is performed, the impact when the windings 1a are in contact with each other is reduced. Further, it is possible to suppress the amplification of vibration of the valve spring 1 caused by an external action due to the rubber coating process. This also suppresses the vibration of the valve spring 1 from reaching the frequency at which surging occurs, and is a countermeasure against surging.

  The above-described embodiments are merely examples for carrying out the present invention, and the present invention is not limited thereto. Various modifications of these embodiments are within the scope of the present invention. It is apparent from the above description that various other embodiments are possible within the scope. For example, the winding 1a can have a rectangular cross section. Thereby, the windings can be brought into surface contact.

It is explanatory drawing which showed schematic structure of the valve apparatus incorporating the valve spring of an Example, (a) shows the valve closing state of a valve apparatus, (b) shows the valve opening state (full lift state) of the valve apparatus. FIG.

Explanation of symbols

1 Valve Spring 1a Winding 2 Valve Device 3 Valve Stem 4 Retainer 5 Valve Spring Seat 6 Valve Lifter 7 Cam

Claims (5)

A valve spring sandwiched between a retainer disposed on one end side of the valve stem and a valve spring seat disposed to face the retainer;
A valve spring characterized in that adjacent windings come into contact with each other during operation. A valve spring sandwiched between a retainer disposed on one end side of the valve stem and a valve spring seat disposed to face the retainer;
A valve spring characterized in that adjacent windings contact each other over the entire length of the spring during valve lift. A valve spring sandwiched between a retainer disposed on one end side of the valve stem and a valve spring seat disposed to face the retainer;
A valve spring characterized in that adjacent windings contact over the entire length of the spring during valve full lift. The valve spring according to any one of claims 1 to 3,
A valve spring characterized in that the winding is coated. A valve device comprising the valve spring according to any one of claims 1 to 4.

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