JP3000533U - Model engine cylinder - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to facilitate replacement of the cylinder liner and prevent distortion of the cylinder and cylinder liner. [Structure] A screw portion 2 is engraved near the top dead center of a cylinder body 1 and a cylinder liner 3 having a screw portion 4 on an upper outer periphery is screwed and fixed to the screw portion 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to improvement of a cylinder of a model engine used for a model airplane or the like.

[0002]

[Prior art]

 In a conventional model engine, a cylinder liner made of dissimilar metal, mainly iron or copper alloy, is press-fitted or shrink-fitted into a cylinder body made of aluminum casting, and then the inner surface of the cylinder liner is ground and the inner surface is plated. It is hardened and finished by such means.

[0003]

[Problems to be solved by the device]

 Since the cylinder described in the prior art is integrally molded by press-fitting or shrink-fitting the cylinder liner, even if the cylinder liner wears, it is not possible to replace only the cylinder liner. Since it is a dissimilar metal such as aluminum casting, iron, or copper alloy, the expansion rate due to temperature rise is different.Therefore, the temperature rise due to operation causes the cylinder and cylinder liner to expand separately, causing internal distortion and This hindered the smooth lifting and lowering movement of the car and was a problem.

Further, since the cylinder and the cylinder liner are integrated as described above, it is difficult to perform plating or surface hardening on the inner surface of the cylinder liner, which is a problem in that it takes time to produce.

The present invention has been made to solve such problems, and makes it easy to replace the cylinder liner by making the cylinder liner a screw type, and the cylinder liner has different expansion coefficients. The purpose is to provide a cylinder for a model engine in which the lower part of the model is free and a relief is provided to prevent distortion.

[0006]

[Means for Solving the Problems]

 The cylinder of the model engine of the present invention is one in which a screw portion 2 is engraved near the top dead center of the cylinder body 1, and a cylinder liner 3 provided with a screw portion 4 on the upper outer periphery is screwed and fixed to the screw portion 2. Is.

The length of the cylinder liner 3 is made longer than the length of the cylinder chamber of the cylinder body 1 so that there is a clearance m between the lower collar portion 3 a and the lower end of the cylinder body 1, and the cylinder body 1 is provided with a cylinder. The liner 3 is fixed. Further, groove holes 3b are provided at several places on the outer circumference of the lower flange portion 3a so that the jig can be held.

[0008]

[Action]

 According to this invention, the threaded portion 4 of the cylinder liner 3 is screwed into the threaded portion 2 near the top dead center of the cylinder body 1 so as to tighten the inner upper end of the cylinder and the upper end of the cylinder liner without a gap, and the lower portion of the cylinder liner. The clearance m is fixed between the flange portion 3a and the lower end of the cylinder body 1 and fixed.

[0009]

【Example】

 1 to 4, reference numeral 1 denotes a cylinder body made of aluminum casting, on which a cylinder head 4 is integrally formed, and a female screw portion 2 is formed near the top dead center of the cylinder chamber.

Reference numeral 3 is a cylinder liner made of iron or copper alloy, etc. formed in the lower flange portion 3a. The length L from the upper end to the flange portion 3a is made longer than the length L ₁ of the cylinder chamber, and A male screw part 4 is engraved near the top dead center of the upper periphery, and when the cylinder liner 3 is screwed into the cylinder body 1, there is a clearance m between the upper surface of the lower collar part 3a and the lower surface of the cylinder body 1. It is installed by tightening and fixing. Grooves 3b are provided on all sides of the lower flange 3a of the cylinder liner 3 in order to be gripped by a jig.

Before the cylinder liner 3 is assembled to the cylinder body 1, only the cylinder liner 3 is plated or surface-hardened.

In the embodiment, 5 is a cylinder head cover, 6 is an intake port, 7 is an intake valve, 8 is a piston, and 9 is a piston rod.

Since the present invention has the above-mentioned structure, the male screw portion 4 of the cylinder liner 3 is screwed into the female screw portion 2 of the cylinder body 1, and the groove 3b of the lower collar portion 3a of the cylinder liner 3 is properly grasped. Grasp it with a tool and tighten it until the upper end of the cylinder liner 3 comes into contact with the upper end of the cylinder chamber 1 against the inner end of the cylinder chamber to eliminate the gap and prevent the output from lowering. It is possible to prevent distortion by allowing the cylinder and cylinder liner to extend and contract freely without interfering with each other by tightening and fixing with a slight clearance m between the bottom and the bottom.

[0014]

[Effect of device]

 According to the present invention, the cylinder liner is screwed into the cylinder body, so that if the cylinder liner is worn due to use, only the cylinder liner can be easily replaced with a new one. In particular, in an engine with a single cylinder and cylinder head, if the cylinder liner becomes worn, the entire cylinder and cylinder head must conventionally be replaced. Running costs can be reduced because only the liner needs to be replaced.

Even if the cylinder body and the cylinder liner are made of different metals and have different thermal expansion coefficients, the cylinder liner is screwed near the top dead center and the lower part is free, and a clearance is provided between the cylinder body and the liner. Therefore, when the temperature rises during operation, the cylinder and cylinder liner can extend downward without interfering with each other and will not cause strain. Therefore, the vertical movement of the piston can be smoothly performed.

Furthermore, since only the liner can be plated or surface hardened before the cylinder liner is assembled to the cylinder body, the production is easy.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view of a cylinder of a model engine of the present invention.

FIG. 2 is a perspective view of a cylinder liner.

FIG. 3 is a plan view of the same.

FIG. 4 is a cross-sectional view of a model engine equipped with the cylinder of the present invention.

[Explanation of symbols]

 1 Cylinder body 2 Screw part 3 Cylinder liner 3a Lower collar part 3b Groove hole 4 Screw part

Claims (3)

[Scope of utility model registration request] 1. A cylinder liner (3) having a threaded portion (2) engraved near the top dead center of the cylinder body (1) and having a threaded portion (4) on the outer periphery of the upper portion of the cylinder main body (1). A model engine cylinder that is fixed by screwing. 2. The length of the cylinder liner (3) is made longer than the length of the cylinder chamber of the cylinder body (1), and the clearance (m) is provided between the lower flange portion (3a) and the lower end of the cylinder body (1). The model engine cylinder according to claim 1, wherein the cylinder is fixed. 3. The cylinder of a model engine according to claim 2, wherein the lower flange portion (3a) of the cylinder liner (3) is provided with slots (3b) at several positions.