JPS6371507A - Valve system - Google Patents

Abstract

PURPOSE:To execute high speed driving easily by pushing a valve against a valve seat by a belleville spring made of shape memory alloy which shows super elasticity at the temperature at the time of operation. CONSTITUTION:A belleville spring 1 made of shape memory alloy consisting of TiNi which shows super elasticity at the temperature at the time of operation is produced. The belleville spring 1 is arranged at a direct driving type valve system device through a circular spacer with a T shaped cross section, and a valve 3 is operated so as to be pushed against a valve seat 4. As natural oscillation of said belleville spring is extremely high, surging is not generated and inertia mass of the valve system becomes small. By this, high speed driving can be executed easily.

Description

[Detailed Description of the Invention] In a valve train for an internal combustion engine, a compression coil spring is usually used to push the valve against the valve seat. However, the characteristics of compression coil springs are not necessarily ideal for internal combustion engines, which are becoming increasingly faster. The weight added to the mass is also not small, and the mounting dimensions of the compression coil breakage are large compared to its stroke, resulting in a longer valve stem and a larger volume of the valve train.

In view of the above, an object of the present invention is to provide a valve train with a small dedicated volume that facilitates high-speed operation.

The structure of the present invention is to press the valve against the valve seat using a shape-memory alloy bellows spring that exhibits superelasticity at operating temperatures, and to prevent the force Δ from leaving when the cam pushes up the valve. In a valve train having this configuration, the natural frequency of the bellows spring is extremely high, so no surge occurs, and the inertial mass of the valve train is also small, making high-speed operation easier. Furthermore, since the superelastic alloy bellows spring has a large stroke compared to its mounting dimensions, the exclusive volume of the valve train is also reduced, contributing to the reduction in size and weight of the entire engine.

In addition to the disk-shaped ``Saraba t'' with its central part punched out as shown in the plan view in Fig. 1, there is also a ``Saraba t'' on the inside or outside of the disk as shown in Figs. 2 and 3. It also includes springs with tooth profiles or notches.

Figure 4 shows how the present invention is applied to a direct drive type valve train V (
In addition, Fig. 5 shows the cross section of the main parts of an example implemented in a swinger type valve train. Since the alloy spring has a zero-strike of more than 50% of its mounting dimensions, the exclusive volume of the valve train can be reduced. Furthermore, the valve shaft length can be shortened, and the weight of the bellows spring added to the inertial mass of the valve train is extremely small, which makes high-speed rotation easier while reducing the possibility of surging.

In addition, 2 in FIG. 5 is an annular base +1 with a T-shaped cross section sandwiched between the bellows springs, which is effective in preventing the tooth profiles from interfering with each other when the bellows spring with internal teeth shown in FIG. 2 is used.

In short, the present invention uses a bellows spring made of a superelastic alloy such as T1Ni that can withstand deformation (strain) of about 10 degrees of steel, and has a small inertial mass, making it easy to operate at high speed.

However, it provides a valve train system that occupies a small volume, and is highly effective in making internal combustion engines smaller, lighter, faster, and more powerful.

[Brief explanation of the drawing]

Fig. 1 is a plan view of a bell spring made of superelastic alloy, Fig. 2 is a plan view of a bell spring with internal teeth, Fig. 3 is a plan view of a bell spring with external teeth, and Fig. 4 is a plan view of a bell spring with external teeth. FIG. 5 is a vertical cross-sectional view of a main part of a direct drive type valve train/device, and FIG. 5 is a vertical cross-sectional view of a main part of a swing arm type valve train. In the figure, numeral 1 is a superelastic alloy spring, and 2 is an annular flat size with a T-shaped cross section.

Claims (1)

[Claims] A valve train that uses a shape-memory alloy bellows spring that exhibits superelasticity at operating temperatures to press the valve against the valve seat and prevent the cam and follower from separating when the cam pushes the valve up.