JPS59229258A - Core for hollow cam shaft consisting of cast iron - Google Patents

Abstract

PURPOSE:To form a cam shaft having a large hollow part and to reduce the weight thereof by projecting radially branch cores from a core body and disposing longitudinally plural pieces of such branch cores. CONSTITUTION:Branch cores 5 are so formed as to project radially from the lateral circumferential surface 7 of a core body 6 and plural pieces of such cores 5 are disposed to the longitudinal direction of the core body 6, thereby constituting a core 4. Since the cores 5 are used as a core print in the stage of casting a hollow cam shaft 8 consisting of a cast iron by using such core 4, the supporting of the core 4 is easy and the venting of the gas is also made easy by the cores 5. Open holes 13 formed by the cores 5 after casting of the cam shaft 9 is used for stripping sand from the core 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a core for a cast iron hollow camshaft.

Conventionally, as a method of providing a hollow part in a cast iron camshaft,
A method of perforating this by drilling or a method of using pipe casting are generally used. However, the drilling method, as shown in Figure 1,
Since the drill hole 2 formed in the camshaft 1 is long, the drill used is also long, and the center of the drill, which is held in a cantilevered manner, is likely to shift. Therefore, if the diameter of the drill is increased, there is a risk of drilling the side peripheral surface 3 of the camshaft 1 depending on the size of the deviation of the drill center, making it impossible to drill a large drill hole 2. In addition, in the pipe casting method, the wall thickness of the pipe is added to the minimum wall thickness of the camshaft determined by the strength, sprue, etc., so that it is not possible to form a large hollow part. On the other hand, a method of forming a hollow part in a cast iron camshaft using a core with a large diameter has not been carried out due to problems in supporting the core.

The present invention aims to provide a core for cast iron hollow camshafts that solves the above-mentioned problems, and is characterized by having a plurality of branch cores protruding in the radial direction from the core body in the longitudinal direction. This is because it was placed in

The present invention will be explained below based on illustrated embodiments.

2 and 3 show one embodiment of the present invention, in which 4 is a core and 5 is a branch core. The branch core 5 is formed to protrude in the radial direction from the side peripheral surface 7 of the core body 6. The core 4 is formed by arranging a plurality of the branch cores 5 in the longitudinal direction of the core body 6. FIG. 3 shows a cast iron hollow camshaft 8 formed using the core 4. In the figure, 9 is a shaft, 10 is a cam, 11 is a journal, 12 is a hollow part, and 13 is an open hole. be.

The hollow portion 12 is formed by removing sand from the core body 6, and the open hole 13 is formed by removing sand from the branch core 5.

When the cast iron hollow camshaft 8 is cast using the core 4 having the above structure, the branch core 5 is used as a core, making it easy to support the core. Further, the branch core 5 also facilitates removal of the gas. After casting the above camshaft 8, the branch core 5
The open hole 13 formed by this is used for removing sand from the core 4.

If a cast iron hollow camshaft is cast using the core according to the present invention, the core can be easily supported, so a core with a large diameter can be used. As a result, a large hollow portion can be provided in the camshaft, and the weight of the camshaft can be significantly reduced.

In addition, after removing sand from the core, the branch core portion becomes an open hole, so it can be used as an MB stopper when tightening a pulley port to the engine oil passage and camshaft end.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a conventional cast iron hollow camshaft, Fig. 2 is a front view showing a core for a cast iron hollow camshaft according to an embodiment of the present invention, and Fig. 3 is a front view showing a core for a cast iron hollow camshaft according to an embodiment of the present invention. FIG. 2 is a front view showing a cast iron hollow camshaft. 4... Core, 5... Branch core,
6... Core body, 8... Cast iron hollow camshaft.

Claims (1)

[Claims] A core for a cast iron hollow camshaft, characterized in that a plurality of branch cores protruding radially from a core body are arranged in the longitudinal direction.