JP2516410Y2 - Synthetic resin cover mounting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a mounting device for a synthetic resin cover used for a cover of an internal combustion engine.

(Prior Art) In an internal combustion engine, particularly an internal combustion engine for a vehicle, a cylinder head cover, a belt cover, or the like is made of synthetic resin for the purpose of weight reduction and cost reduction. However, generally, synthetic resin has rigidity higher than that of metal. Since it is low, if the synthetic resin product is bolted to the engine body which is a metal product as it is, the tightening force cannot be endured, and the flange portion where the bolting is carried out is cracked.

Therefore, as in Japanese Utility Model Laid-Open No. 55-64458, a metal collar, which is slightly smaller than the wall thickness of the flange, is fitted into a through hole that is a hole through which the bolt is passed, and this collar bears a part of the tightening force of the bolt. The entire tightening force is not applied to the flange.

(Problems to be solved by the invention) However, recently, in vehicles, the number of air-conditioning facilities and devices arranged in the engine room has increased, ventilation in the engine room has deteriorated, and the temperature has risen. Vibration is getting stronger. The coefficient of thermal expansion of the constituent parts of the synthetic resin cover varies depending on the temperature rise in the engine room. In other words, the degree of expansion of the synthetic resin differs between the flange part that is tightened with bolts and has no freedom of movement, and the cover side wall part that has relatively freedom, and the degree of freedom with the flange part where vibration of the engine is also fixed. Since it behaves differently from a cover side wall with a sine, the stresses of expansion and vibration are intricately entangled in a complicated manner and are almost perpendicular, so concentrate on the connection part that is the connection part of the cover side wall of the flange part. It acts and causes cracks in the connection.

The occurrence of such cracks is prominent at a large initial stress (the size of the crack is determined by the distance from the gate, the flow direction of the molten resin, the state of merging of the molten resin, etc.).

(Means for Solving the Problem) The present invention provides a synthetic resin cover mounting device in which a flange portion having a through hole is formed at a lower end of a side wall portion, and a bolt is inserted into the through hole to fasten it. A recess is formed in the connecting portion of the flange portion with the side wall portion.

(Function) The expansion of the synthetic resin due to heat increases on the side wall of the cover and tends to move toward the top of the cover, but the expansion is small at the flange because it is fixed to the engine by bolts. Further, the side wall of the cover, particularly the vicinity of the top, shakes in the left-right direction due to the vibration, but the flange performs the same vibration as the engine. Due to the expansion and vibration, the movement of the cover side wall gives a stress to the fixed flange portion, but the recess formed in the connecting portion of the flange portion with the cover side wall causes the stress from the cover side wall to form the shape of the recess. And disperse along the line to suppress the clutch that tends to develop at the connection.

(Example) A rocker cover, which is one of synthetic resin covers, is a box type made of synthetic resin such as polypropylene or nylon as shown in Figs.
A plurality of flange portions 2 are provided at intervals on the periphery of the cover side wall portion 1 which is the surrounding wall, and a connecting portion 3 is formed at a connecting portion of the flange portion 2 with the side wall portion 1. A through hole 4 for inserting a bolt is formed in each flange portion 2, and a metal collar 5 having a height substantially equal to the wall thickness of the flange portion 2 is fitted in the through hole 4. And flange 2
A concave portion 6 is formed in the connecting portion 3 with the side wall portion 1.
The concave portion 6 has a configuration in which it is gradually dug into a U shape from both sides of the flange portion 2, the through hole 4 and the cover side wall portion 1. Then, the rocker cover is arranged at a predetermined position of the engine body, each flange portion 2 is provided with a washer 7, the bolts 8 of the metal collar 5 are respectively inserted, and screwed into the screw hole of the engine body through the packing 9 to make the compression tight. Let

As another embodiment, as shown in FIG. 3, recesses 14 are formed at all the connection portions 13 of the flange portion 12 with the cover side wall portion 11.

The cross-sectional shape of the recess is not limited to the U shape, but may be a V shape.

(Advantages of the Invention) As described above, the present invention provides a synthetic resin cover mounting device in which a flange portion having a through hole is formed at a lower end of a side wall portion, and a bolt is inserted into the through hole to fasten. Since the concave part is formed in the connection part of the flange part with the side wall part, even if complicated stress due to thermal expansion of the synthetic resin and vibration of the engine is applied to the connection part, the stress is dispersed in the concave part and no cracks occur. A synthetic resin cover can be used.

[Brief description of drawings]

FIG. 1 is a sectional view of a mounting portion of a synthetic resin cover, FIG. 2 is a perspective view of the mounting portion, and FIG. 3 is a perspective view of a mounting portion in another embodiment. 1 ... Cover side wall part, 2 ... Flange part 3 ... Connection part, 6 ... Recessed part

Claims (1)

(57) [Scope of utility model registration request] 1. A mounting device for a synthetic resin cover, wherein a flange portion having a through hole is formed at a lower end of the side wall portion, and a bolt is inserted into the through hole to fasten the flange portion. An attachment device for a synthetic resin cover, characterized in that a recess is formed in the portion.