JPH0564405U - Valve spring mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a valve spring mechanism capable of preventing an excess or deficiency of a spring load due to a change in an engine speed, and preventing a friction loss at the time of operating a valve and an increase in fuel consumption. [Structure] An intake / exhaust valve 1 of an engine is interposed between a spring retainer 4 and a seat plate 9 mounted on a spring seat 8 of a cylinder head of the engine to urge the valve 1 in a closing direction. A valve spring mechanism including a valve spring (7), wherein a set length of the valve spring (7) determined by a distance between a seat plate (9) and a spring retainer (4) when the valve is closed is variable according to an engine speed. Is the valve spring 7 in the high rotation range
By setting so that the spring load of is larger than the spring load in the low rotation range, it is possible to obtain the optimum spring load without excess or deficiency corresponding to each rotation range.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a valve spring mechanism provided in an intake / exhaust valve of an engine.

[0002]

[Prior Art]

 A conventional valve spring mechanism will be described with reference to FIG. 3. An intake / exhaust valve (hereinafter simply referred to as a valve) 1 is vertically slidably inserted into a valve guide 3 mounted on an upper deck 2 of a cylinder. A spring retainer 4 is fixed to the upper end of the valve 1, and a spring seat 5 is formed on the upper surface of the upper deck 2 facing the spring retainer 4. A valve spring 7 is interposed between the spring retainer 4 and the spring washer 6 mounted on the spring seat 5, and normally urges the valve 1 in the closing direction. In such a conventional valve spring mechanism, the set length of the valve spring 7, that is, the length of the valve spring 7 in the closed state of the valve 1 is always constant, and the closing load of the valve 1 is always constant. ..

[0003]

[Problems to be solved by the device]

 By the way, in such a valve spring mechanism, it is a normal practice to set the closing load by the valve spring 7 to a high load in order to prevent irregular movements such as jumps and bounces due to inertia of the valve train associated with high engine speed. It is being appreciated. However, when the load is set to a high load in this way, the load becomes excessive when the engine is running at low speed, and friction loss increases when the valve 1 operates, which has the drawback of increasing fuel consumption. Was.

[0004]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention is interposed between a spring retainer provided in an intake / exhaust valve of an engine and a seat plate attached to a spring seat of a cylinder head of the engine to attach the valve in a closing direction. A valve spring mechanism provided with a biasing valve spring, wherein a set length of the valve spring, which is determined by a distance between the seat plate and the spring retainer when the valve is closed, is variable according to an engine speed. Composed.

[0005]

[Action]

 In the valve spring mechanism of the present invention, the set length of the valve spring is variable according to the engine speed, and the set length is set to be shorter in the high engine speed range than in the low engine speed range. The load can be set to the minimum load that does not cause irregular motion such as jump or bounce due to the inertia of the valve train, depending on each rotation range.

[0006]

【Example】

 Next, an embodiment of the present invention will be described with reference to FIGS. In the drawing, the same members as those in the above-mentioned conventional example are designated by the same reference numerals and detailed description thereof will be omitted. In this embodiment, a movable seat plate 9 that supports a lower portion of the spring washer 6 of the valve spring 7 is attached to the spring seat 8 of the valve spring 7. A hydraulic chamber 10 is formed between the movable seat plate 9 and the bottom of the spring seat 8 as shown in FIG. 2, and the hydraulic chamber 10 is connected to a hydraulic source (not shown) via a hydraulic passage 11. Has been. A hydraulic valve 12 is provided in the middle of the hydraulic passage 11. The hydraulic valve 12 blocks the communication between the hydraulic chamber 10 and the hydraulic source, and the pressure oil in the hydraulic chamber 10 flows through the branch passage 13. And a second position that allows communication between the hydraulic chamber 10 and the hydraulic source and that prevents the pressure oil in the hydraulic chamber 10 from being released to the outside via the branch passage 13. It is possible to switch to.

The operation of the above-described embodiment will be described. First, the hydraulic valve 12 is located at the first position in the low engine speed region. In this position, the communication between the hydraulic chamber 10 and the hydraulic source is cut off, and the pressure oil in the hydraulic chamber 10 is released to the outside through the branch passage 13. Therefore, as shown in FIG. The movable seat plate 9 that supports the lower part of the spring washer 6 of the spring 7 comes into contact with the spring seat 8, and the set length S1 of the valve spring 7 becomes the maximum length. On the other hand, in the high engine speed range, the hydraulic valve 12 is located at the second position, pressure oil is introduced into the hydraulic chamber 10 from the hydraulic source, and the movable seat plate 9 is lifted from the spring seat 8 as shown in FIG. As a result, the set length S2 of the valve spring 7 becomes shorter than the set length S1 in the low rotation range.

That is, in this embodiment, the spring load of the valve spring 7 becomes larger than the spring load in the low rotation range in the high rotation range of the engine, and these loads are jumped by the inertia of the valve train in each rotation range. By setting the minimum load that does not cause irregular movements such as bounce, optimal load without excess or deficiency according to each rotation range can be obtained, and friction loss increases when the valve 1 operates and fuel consumption accompanying it increases. It can prevent the increase.

[0009]

[Effect of the device]

 With the valve spring mechanism of the present invention, the spring load of the valve spring can be set to the minimum load that does not cause irregular movements such as jumps and bounces due to the inertia of the valve operating system, depending on each rotation range. Since the optimum load can be obtained without any excess or deficiency, there is an advantage that it is possible to prevent an increase in friction loss during valve operation and an accompanying increase in fuel consumption.

[Brief description of drawings]

FIG. 1 is a front view of a valve spring mechanism according to an embodiment of the present invention.

FIG. 2 is a front view similar to FIG. 1 showing different operating states.

FIG. 3 is a front view of a conventional valve spring mechanism.

[Explanation of symbols]

 1 valve 2 upper deck 4 spring retainer 7 valve spring 8 spring seat 9 movable seat plate 10 hydraulic chamber

Claims (1)

[Scope of utility model registration request] 1. A valve spring, which is interposed between a spring retainer provided in an intake / exhaust valve of an engine and a seat plate attached to a spring seat of a cylinder head of the engine to urge the valve in a closing direction. A valve spring mechanism provided, wherein a set length of the valve spring, which is determined by a distance between the seat plate and the spring retainer when the valve is closed, is variable according to an engine speed. Valve spring mechanism that enables.