JPH0450432Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a balance weight structure for a rotary piston engine.

(Prior Art) Conventionally, in a rotary piston engine in which a rotor attached to an eccentric shaft rotates planetarily within a casing, a balance weight is provided on the eccentric shaft to eliminate deviation of the center of gravity from the center of rotation of the rotor. is being carried out (for example, in 1987-
(Refer to Publication No. 32516).

Further, a sprocket for driving a chain for driving engine auxiliary equipment is attached to the eccentric shaft, and rubber is baked and fixed on both sides of the sprocket, so that the teeth generated when the chain comes into contact with the sprocket are fixed. It is designed to prevent the occurrence of hitting sounds.

(Problem that the invention aims to solve) By the way, the eccentric shaft of a rotary piston engine is an output shaft that receives the explosive force acting on the rotor at the rotor bearing eccentric to the center of rotation and extracts it as rotational force. Therefore, there is a problem in that torque fluctuations occur on the eccentric shaft, and the torque fluctuations are transmitted to the engine auxiliary equipment via the sprocket fixed to the eccentric shaft.

Therefore, it may be possible to attach a damper weight to the eccentric shaft to alleviate torque fluctuations, but the vibration frequency of a rotary piston engine is extremely low, and the damper weight has a large weight (approximately
(approximately 1.5 kg), which not only increases the total weight of the engine but also requires a large space within the limited engine room, which is disadvantageous in terms of weight and space.

The present invention has been devised in view of these points, and it is an object of the present invention to provide a balance weight structure for a rotary piston engine that can suppress torque fluctuations without being disadvantageous in terms of weight or space.

(Means for Solving the Problems) In order to achieve the above object, the present invention has a sprocket fixed to an eccentric shaft of a rotary piston engine for driving an engine accessory drive chain.
A rubber-like elastic body for preventing chain rattling noise is fixed to at least the side surface of the sprocket where the chain contacts, and a balance weight rotates on the eccentric shaft to correct the deviation between the center of rotation of the eccentric shaft and the center of gravity. The balance weight and the sprocket are elastically connected via the rubber-like elastic body.

(Function) The rotatable balance weight and the rubber-like elastic body for preventing rattling of the sprocket are combined together to function as a dynamic damper and absorb torque fluctuations of the eccentric shaft.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

In FIG. 1, reference numeral 1 denotes an eccentric shaft of a rotary piston engine, on which a sprocket 3 for driving a chain 2 for driving an engine accessory (for example, an oil pump) is fixedly installed.

A substantially semicircular balance weight 4 is disposed adjacent to the sprocket 3 on the eccentric shaft 1 via a cylindrical sleeve 5 so as to be rotatable in the circumferential direction.

That is, as shown in FIGS. 2 and 3, the sleeve 5 and the balance weight 4 are attached to the eccentric shaft 1 via the key 6, and the key 6 is loosely fitted into the key groove 4a of the balance weight 4. The balance weight 4 is allowed to rotate by ±3 degrees in the circumferential direction relative to the sleeve 5 fixed to the shaft 1. 5a is a keyhole formed in the sleeve 5.

On both sides of the sprocket 3, rubber-like elastic bodies 7 and 8 for preventing chain rattle are fixed by adhesive or baking to at least the portions where the chain 2 comes into contact. Of the rubber-like elastic bodies 7 and 8, the elastic body 8 on the balance weight 4 side is also fixed to the balance weight 4, and the balance weight 4 is elastically coupled to the sprocket 3 via the rubber-like elastic body 8. There is. Thereby, the distance between the sprocket 3 and the balance weight 4 can be reduced.

In addition, in Fig. 2, 9 is the front rotor,
10 is a rear rotor, and the balance weight 4 is for the front rotor 9.

If configured as above, balance weight 4
can rotate in the circumferential direction, and the balance weight 4
It is elastically connected to the sprocket 3 fixedly attached to the eccentric shaft 1 via the rubber-like elastic body 8, and since the sprocket 3 is fixed to the eccentric shaft 1, the vibration of the eccentric shaft 1 is suppressed. Sprocket 3
However, the balance weight 4 and the rubber-like elastic body 8 function as a dynamic damper to absorb and alleviate torque fluctuations of the eccentric shaft 1.

Also, the rotation of the balance weight 4 is controlled by the key groove 4.
Since only a certain range is allowed by a and the key 6, a force exceeding a certain level does not act on the rubber-like elastic body 8, and even if the rubber-like elastic body 8 is separated due to deterioration, the balance weight 4 is prohibited from freely rotating in the circumferential direction.

(Effects of the invention) As described above, the present invention allows a dynamic damper to be constructed using a balance weight and a rubber-like elastic body for preventing chain rattling noise. , torque fluctuations can be suppressed without incurring disadvantages in terms of space.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a cross-sectional view showing the balance weight structure of a rotary piston engine, FIG. 2 is an explanatory diagram of the rotation of the balance weight, and FIG. 3 is a perspective view of the sleeve. 1... Eccentric shaft, 2... Chain, 3... Sprocket, 4... Balance weight, 8... Rubber-like elastic body.

Claims (1)

[Scope of utility model registration request] A sprocket for driving a chain for driving engine auxiliary equipment is fixed to the eccentric shaft of the rotary piston engine, and a rubber-like elastic body for preventing chain rattling noise is fixed to the side surface of the sprocket at least at the part where the chain comes into contact with the sprocket. A balance weight is rotatably attached to the eccentric shaft to correct a deviation between the center of rotation of the eccentric shaft and the center of gravity, and the balance weight and the sprocket are elastically coupled via the rubber-like elastic body. Balance weight structure of rotary piston engine.