JPS63195471A - Expander for piston ring - Google Patents

Abstract

PURPOSE:To eliminate a clearance in the sliding direction of a piston, by forming plural bending parts in a stripped material and providing at least one of the fold lines in the bending part to form a non-right angle with respect to the lengthwise direction while setting the height of a ring-shaped expander larger than that of the material. CONSTITUTION:An expander 1, which is constituted forming a stripped material W of spring steel or the like of thickness (t) into a ring shape, is formed into a corrugated shape over the total periphery by plural bending parts 2, providing a fold line l1 of the mutually opposed two bending parts 2-1 to form a non-right angle with respect to the lengthwise direction and a fold line l2 of the other bending parts 2-2 to form a right angle. Accordingly, the expander 1 is formed being folded into a horizontal doglegged shape in the sliding direction of a piston, setting the total height H' larger than the height H of the material W. And if the expander is inserted and fitted into a ring groove 4 of the piston 3 in the internal peripheral side of a second ring 5, the expander 1, having elasticity, is always placed in a tense condition in the ring groove 4, eliminating clearance in the sliding direction of the piston. In this way, the expander enables durability to be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an expander for a piston link that eliminates a gap between the expander and the ring groove in the sliding direction of the piston.

(Prior Art) Generally, in a two-stroke engine, an expander 101 that is effective in reducing the slap sound (hitting sound) of the piston 3 is installed in the second ring groove 4 of the piston 3, as shown in FIGS. 4 to 6. In many cases, it is interposed on the inner circumferential side of the link 5. FIG. 4 is a partially cutaway side view of the piston 3.
Figure 5 is an enlarged detailed view of part A in Figure 4, and Figure 6 is the ■■ in Figure 4.
It is a sectional view taken along the line -■.

As shown in the partial side view of FIG. 7 and the partial plan view of FIG. A plurality of bent portions 102 are formed and the whole is formed into a ring shape, and this is done by constantly urging the second ring 5 shown in FIGS. 4 to 6 radially outward. The slapping sound of the piston 3 is reduced by pressing it against a cylinder wall (not shown).

(Problem to be solved by the invention) However, in the conventional expander 101, each bent portion 102 is perpendicular to the length direction of the material, so its width is equal to the material width H. They matched, and the upper and lower end surfaces constituted straight surfaces. Therefore, the expander 101 is rigid in the width direction (up and down direction) and does not deform, and when it is assembled into the ring yt4 of the piston 3, the expander 101 and the ring groove 4 are connected as shown in FIG. A gap C inevitably existed between them in the sliding direction of the piston 3 (vertical direction in FIG. 5).

By the way, in the case of a two-stroke engine equipped with an expander having a high specific output, the above-mentioned condition is further reduced under disadvantageous conditions such as a decrease in the strength of the piston material due to an increase in heat load and an increase in inertia due to the expander's own weight due to high rotation. Due to the existence of the gap C between the expander 101 and the link groove 4, an impact force is applied in the piston sliding direction due to the expander's own weight.

As a result, in the worst case, if the temperature of the piston 3 is relatively high (generally on the ceiling side on the exhaust side), the piston 3 will move in the sliding direction (vertical direction in FIG. 9) as shown in FIG. Biting portions a and b occur in the piston, causing problems such as damage to the piston second land 3a, wear of the upper end surface of the expander 101, and breakage of the bent portion 102.

The present invention has been made in view of the above problems, and its purpose is to reduce the impact by eliminating the gap between the piston and the ring groove in the sliding direction, thereby increasing the durability of the piston and the piston. To provide expanders for piston links.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a piston ring expander in which a plurality of bent portions are formed in a strip-shaped material and the entire ring shape is formed, in which a polygonal line of the bent portions is provided. The expander includes one that is not perpendicular to the length direction of the material, and the height of the entire expander is higher than the height of the material.

(Function) Since the expander has elasticity and easily deforms not only in the radial direction but also in the sliding direction of the piston,
If this is incorporated into the ring groove of the piston and the ring groove is always tensioned in the vertical direction, the gap between the expander and the ring groove in the piston sliding direction can be eliminated, and the inertia caused by the expander's own weight can be eliminated. The force is absorbed by the elasticity of the expander in the sliding direction of the piston, thereby alleviating the impact force, thereby preventing a decrease in the durability of the piston and the expander due to the impact force.

(Example) An example of the present invention will be described below based on the accompanying drawings.

FIG. 1(a) is a partial side view of a strip material W made of spring steel or the like having a height H1 and a thickness t, and the strip material W is formed into a ring shape as a whole (see FIG. 6). As shown in Fig. 1(b), the expander l according to the present invention is formed with a plurality of bent parts 2, which are formed in a wave shape over the entire circumference (Figs. 6 and 8). (see figure), and the bending line 1. of the two opposing bending portions 2-1.2-1. ．． look.

S is inclined at a non-perpendicular angle to the length direction of the material W.
The bending lines 2 of the other bent portions 2-2-- are perpendicular to the length direction of the material W. Therefore,
As shown in FIG. 1(b), the expander 1 as a whole is bent in the piston sliding direction (in the vertical direction in the figure) into a horizontal square shape at the bent portion 2-1 and 2-1. , and its overall width H' is higher than the width H of the material W (H'
〉H) Since the expander 1 is bent in the piston sliding direction as described above, it has elasticity not only in the radial direction but also in the piston sliding direction, and can be deformed in the same piston sliding direction. It acts as a spring.

If such an expander l is fitted to the inner peripheral side of the second ring 5 in the ring groove 4 of the piston 3 as shown in the partial sectional view of FIG. 2, the expander l will move in the sliding direction of the piston 3 ( Since it has elasticity also in the vertical direction (in Fig. 2), it is always tensioned in the vertical direction within the ring groove 4, and there is a gap between the expander l and the ring groove 4 in the piston sliding direction (vertical direction). disappears. By eliminating this gap, the expander 1 no longer shakes during the operation of the piston 3, and the inertia force based on the own weight of the expander 1 is absorbed by the elasticity of the expander 1 itself in the direction of the piston sliding force.
The impact force accompanying this inertial force is alleviated, and damage to the piston 3 and wear and tear of the expander 1 are avoided, thereby improving the durability of the piston 3 and expander 1. It goes without saying that the expander 1 fulfills its original function of ejecting the second ring 5 radially outward to reduce the slap sound of the piston 3.

FIG. 3 shows an expander 11 according to a modified embodiment of the present invention.
As shown in the side view, the expander 11 has a bent portion 12.
Looking at the line of ...1. Love 2. As a result, the expander 11 is formed into a wavy shape in the piston sliding direction (vertical direction in FIG. 3), and its overall width H' is higher than the material @H (H'>H), and has elasticity also in the piston sliding direction.

Accordingly, the above-mentioned method is also provided by Woodworking Kiss Spander 11.

It is possible to obtain the same effect as that obtained in the first embodiment.

It should be noted that the expander according to the present invention may have any shape other than those shown in the above embodiments, but the key is to have appropriate elasticity and tension in the piston sliding direction from the viewpoint of balance with inertia force. It satisfies the following requirements: it has a curvature that creates a contact point that is effective in preventing the ring groove from digging into the ceiling side in the exhaust direction, there is no vertical directionality, and it is easy to assemble into the ring groove. All you need is something to do.

(Effects of the Invention) As is clear from the above description, according to the present invention, since the expander has elasticity also in the piston sliding direction, it is possible to eliminate the gap between the expander and the ring groove in the piston sliding direction. This has the effect of absorbing the inertia force due to the expander's own weight by the expander's elasticity in the sliding direction of the piston, mitigating the impact force, and preventing the durability of the piston and expander from decreasing due to this impact force. .

[Brief explanation of the drawing]

FIG. 1(a) is a stock drawing, FIG. 1(b) is a side view of the expander according to the present invention, FIG. 2 is a cross-sectional view of the piston ring groove showing the expander according to the present invention installed, and FIG. The figures are a side view of an expander according to a modified embodiment of the present invention, FIG. 4 is a partially cutaway side view of a piston incorporating a conventional expander, FIG. 5 is an enlarged detailed view of section A in FIG. 4, and FIG. is a sectional view taken along the line VI-Vl in Fig. 4, and Fig. 7
The figure is a partial side view of a conventional expander, FIG. 8 is a partial plan view of the same expander, and FIG. 9 is a sectional view of a piston ring groove showing a damaged state of the piston. l, 11...Expander, 2,12...Bending portion, H...Material height, H'...Expander height,
Sentence 89 Sentence 2... Broken line, W... Material.

Claims (1)

[Claims] In a piston ring expander that is formed into a ring shape by forming a plurality of bent portions on a strip-shaped material, the overall height is A piston ring expander characterized by being configured such that the height is higher than the material height.