HEATING DEVICE AND MANUFACTURING METHOD THEREOF

Abstract

A heating device includes: a plate-shaped heating substrate; and a hollow rod material an end face of which is joined to one surface of the heating substrate, and the heating substrate includes a lateral surface portion and a concave surface portion in the vicinity of a joint with the hollow rod material. The lateral surface portion forms a same plane surface with an outer peripheral surface of the hollow rod material, and the concave surface portion connects to the lateral surface portion. Moreover, an edge of a joint interface of the heating substrate and the hollow rod material is located between the lateral surface portion of the heating substrate and the outer peripheral surface of the hollow rod material.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The above and further objects, features and advantages of the invention will more fully appear in the detailed description of embodiments of the invention, when the same is read in conjunction with the drawings, in which:

FIG. 1 is a schematic longitudinal sectional view showing an embodiment of a heating device according to the present invention;

FIG. 2A is a schematic longitudinal sectional view showing another embodiment of the heating device according to the present invention;

FIG. 2B is an enlarged view of a part of FIG. 2A;

FIG. 3 is a schematic longitudinal sectional view showing a heating device of a comparative example; and

FIG. 4 is a schematic longitudinal sectional view showing a heating device of another comparative example.

Claims

1. A heating device, comprising: a plate-shaped heating substrate; anda hollow rod material an end face of which is joined to one surface of the heating substrate, whereinthe heating substrate includes a lateral surface portion and a concave surface portion in the vicinity of a joint with the hollow rod material, the lateral surface portion forming a same plane surface with an outer peripheral surface of the hollow rod material, the concave surface portion connecting to the lateral surface portion, andan edge of a joint interface of the heating substrate and the hollow rod material is located between the lateral surface portion of the heating substrate and the outer peripheral surface of the hollow rod material.

2. The heating device according to claim 1, wherein a curvature radius R of the concave surface portion is 1 to 10 mm.

3. The heating device according to claim 1, wherein the concave surface portion has an elliptic arc shape in a section including a central axis line of the hollow rod material.

4. The heating device according to claim 1, wherein the concave surface portion has a center line average roughness Ra of not more than 0.8 μm.

5. A method of manufacturing a heating device, comprising the steps of: joining an end face of a hollow rod material to one surface of a heating substrate; andgrinding a concave surface portion formed in the heating substrate in the vicinity of a joint of the heating substrate and the hollow rod material, whereinthe grinding is performed under conditions where grain size and feed speed of a grinding wheel are No. 325 or more and 0.2 mm/min or less, respectively.