JPH0417799Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a spacer expander for a combination oil ring used in an internal combustion engine.

[Conventional technology]

A combination oil ring usually has one side rail arranged on the upper and lower surfaces of one spacer expander, and the side rails are brought into sliding contact with the inner wall of the cylinder by the spacer expander to scrape up and scrape down lubricating oil. This is to ensure that an appropriate oil film is always formed on the cylinder inner wall to minimize wear on the piston ring and cylinder.

There are several types of spacer expanders, but one that is already known is that the outer top piece and the inner bottom piece are spaced apart in the radial direction and arranged alternately in the circumferential direction, and that there is an intermediate portion between them. There is a circumferential corrugated spacer expander connected in pieces.

[Problem that the invention attempts to solve]

Therefore, when trying to expand the abutment of the spacer expander and insert it into the ring groove of the piston, abutting the abutment of the spacer expander within the ring groove, and then assembling the side rails, one of the abutments of the spacer expander There may be cases where one crosses over the other and the abutments overlap.

When assembled to the piston in such a state, tension cannot be applied to the side rail and the spacer expander does not function.

The present invention aims to prevent such problems and improve the spacer expander so that it can be properly assembled to the piston.

[Means for solving problems]

The structure of the present invention that achieves the above-mentioned problems is a circumferentially corrugated structure in which outer top pieces and inner bottom pieces are arranged radially apart and alternately in the circumferential direction, and are connected by an intermediate piece. In the spacer expander,
A guide rod is inserted through the through-hole provided in the intermediate piece and placed across the abutment, and a heat-shrinkable tube made of heat-resistant resin for locking is covered at or near the tip of one side of the guide rod. It is characterized by shrinkage and fixation.

[Effect]

The guide rod, which is attached to the spacer expander while straddling the abutment, is prevented from moving in the circumferential direction of the through hole by the locking heat shrink tube being locked to the spacer expander. Ru. When the spacer expander is assembled into the piston ring groove and the abutment of the spacer expander is expanded, the through hole in the middle piece of the spacer expander slides along the guide rod, and the abutment is always guided by the guide rod. It spreads. After the piston ring is inserted into the groove, when the abutment of the spacer expander is closed, the through hole in the middle piece of the spacer expander slides along the guide rod, as described above, and the abutment is always guided by the guide rod. , the spacer expander returns to its original state with the abutments closed without the abutments overlapping.

〔Example〕

Figure 1 is a perspective view showing the vicinity of the abutment of the spacer expander with the guide rod attached, showing the abutment closed, and Figure 2 is a cross-sectional view of the ring groove portion of the piston incorporating the spacer expander and side rail. It is.

A spacer expander 1 includes a plurality of outer top pieces 2 and inner bottom pieces 3 extending in the circumferential direction, which are spaced apart in the radial direction and arranged alternately in the circumferential direction, and an intermediate piece 4 extending in the radial direction between them. It consists of circumferentially corrugated strips connected by . Each intermediate piece 4 is provided with an elongated through hole 6 that serves as an oil return hole.

The guide rod 7 is a curved round rod with a circular cross section and approximately the same curvature as the spacer expander 1;
Most are made of steel wire, which has elasticity at high temperatures, but any material such as resin may be used as long as it has heat resistance of 200°C or higher. Further, the cross-sectional shape is not limited to a circular shape, and the more preferably the cross-sectional shape is curved with a curvature close to that of the spacer expander 1.

When installing the spacer expander 1 in the ring groove 10 of the piston 9 as shown in FIG. 2, the guide rod 7 is inserted into the spacer expander 1.
The guide rod 7 is inserted into the through hole 6 provided in the middle piece 4 of the guide rod 7, and a heat-shrink tube 8 made of a heat-resistant resin for locking made of fluororesin or the like is covered near the tip of one side of the guide rod 7, and the tube 8 is straddled across the abutment 5. Attach it to the spacer expander 1 in a loose state. Then, the locking heat-shrinkable tube 8 is heated to shrink and fix the locking heat-shrinkable tube 8 to the guide rod 7. Therefore, the guide rod 7 is prevented from moving in the circumferential direction through the through hole 6 by the locking heat shrink tube 8 being locked to the spacer expander 1. Note that the mounting position of the heat-shrinkable tube 8 is not limited to the above example, and may be fixed to the tip of the guide rod 7 or its vicinity. In this case, the heat shrink tube 8 is fixed to the guide rod 7 part between the inner bottom pieces 3 in the illustrated example, but of course it is fixed to the guide rod 7 part of the inner bottom piece 3. You may.

Therefore, if the guide rod 7 is attached to the spacer expander 1 as described above before assembling it to the piston 9, when assembling the spacer expander 1 to the piston ring groove 10, the abutment 5 of the spacer expander 1 can be When expanded, the through hole 6 of the intermediate piece 4 of the spacer expander 1 is connected to the guide rod 7.
, and the abutment 5 is always guided by the guide rod 7 and widened. and piston ring groove 10
When the abutment 5 of the spacer expander 1 is closed after being attached to the spacer expander 1, the through hole 6 of the intermediate piece 4 of the spacer expander 1 slides along the guide rod 7, and the abutment 5 is always connected to the guide rod 7. , the spacer expander 1 returns to its original state with the abutment closed without the abutment 5 overlapping.

In FIG. 2, reference numeral 11 indicates side rails disposed on the upper and lower surfaces of the spacer expander 1;
is a cylinder.

[Effect of idea]

As explained above, according to the present invention, in the circumferential wave type spacer expander, the guide rod is inserted through the through hole provided in the intermediate piece and is disposed astride the abutment, and the guide rod By covering the end of one side of the spacer expander or its vicinity with a heat-shrink tube made of heat-resistant resin for locking and shrinking and fixing it, one side of the abutment of the spacer expander can climb over the other when assembling the spacer expander into the piston ring groove. It is possible to reliably prevent the abutments from overlapping. In addition, since the work of covering the locking heat-shrinkable tube and shrinking and fixing it can be easily performed, productivity is increased.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG.
The figure is a sectional view of a ring groove portion of a piston incorporating a spacer expander and a side rail. 1 is a spacer expander, 2 is an outer top piece,
3 is an inner bottom piece, 4 is an intermediate piece, 5 is an abutment, 6 is a through hole, 7 is a guide rod, 8 is a heat shrink tube for locking, 9 is a piston, and 10 is a ring groove.

Claims (1)

[Scope of utility model registration request] In a circumferential wave type spacer expander in which outer top pieces and inner bottom pieces are arranged radially apart and alternately in the circumferential direction and are connected by an intermediate piece, the guide rod is connected to the intermediate piece. The guide rod is inserted through a through-hole provided in the piece and placed across the abutment, and a heat-shrinkable tube made of heat-resistant resin for locking is placed on or near the tip of one side of the guide rod to shrink and secure it. Features a structure that prevents spacer expanders from overlapping.