JPS6136722Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a camshaft, particularly a camshaft that integrally has a gear for driving a cam, a lubricating oil pump, etc.

In general, the above-mentioned camshafts are either formed by casting or forging, depending on the required strength or for reasons such as productivity and cost.

In a cast camshaft, the cam surface can easily be hardened to the desired hardness by hardening the raw material or by cold hardening the raw material after casting, but with an integrally formed cast gear, the pump There is not enough strength to drive the

On the other hand, a forged camshaft, in contrast to a cast camshaft, has the problem that although it can provide sufficient strength as a gear, it is difficult to obtain the hardness required for the cam surface.

Since the cast camshaft has better productivity and is cheaper than the forged camshaft,
Originally, it would be desirable to prepare a cast camshaft and assemble a gear made of steel or other material to it, but if the gear is to be set in the center of the camshaft, splines or It is difficult to fix the gear to the shaft with a key, etc., and if we place emphasis on productivity and cost, the gear must be a cast gear integral with a cast camshaft, and the strength required for the gear is Currently, designs are designed to compensate for this by using other means other than the material, such as increasing the size.

In addition, similar to the above, the idea of providing a split gear with a forged tooth ring part on a cast shaft was based on the Jikkosho era.
Seen in Publication No. 35-2110. In other words, when installing a gear in the middle of a wheel that is integrally formed by casting wheels with large diameters at both ends, the part with a complicated shape and structure, that is, the cast steel ring part, is made into a split mold and integrated with bolts. In addition, a transmission split gear for an electric train is formed by welding and integrating a cast gear ring part which has a counterweight part on the outer circumferential surface of the ring part and is integrally formed with the ring part. Since the gear parts are welded, and the axle and the collar parts are joined by keys, the structure is complicated and assembly, including alignment, is difficult.

The present invention was devised in view of the above, and its gist is to drill a screw hole or bolt hole perpendicular to the axis of the cast camshaft in the part where the gear is assembled, and to drill a bolt hole parallel to the axis. to 2
A semi-cylindrical recess formed on the inner periphery of the divided steel gear part is aligned with the gear setting part of the camshaft, and a bolt hole facing the axis of the gear part and a screw hole or bolt of the camshaft are fitted. The gear portion is fixed to the shaft by inserting a bolt into the hole.

An embodiment of the present invention will be described below with reference to the drawings. Reference numeral 10 denotes a cast camshaft, each of which is integrally equipped with a plurality of cams 11 or bearings (not shown).

A portion 12 of the camshaft to which a gear portion 20, which will be described later, is assembled is machined to ensure surface accuracy. Further, a screw hole 13 is bored in the gear assembly portion 12 in a direction perpendicular to the axis L.

Reference numeral 20 denotes a gear part made of steel, which consists of an upper gear part 21 and a lower gear part 22, which are divided into upper and lower halves along a plane passing through the axis L (the dividing plane is indicated by S in the figure). Semi-cylindrical recesses 23 and 24 centered on the axis L are provided on the inner periphery of the upper and lower gears 21 and 22, respectively, and the recesses 23 and 24 as well as the dividing surface S The parts are machined to ensure accuracy. Therefore, when the gear part 20 is configured by the gear upper part 21 and the gear lower part 22, the dividing surfaces S are in close contact with each other and the recesses 23, 2
4, a hollow portion 25 corresponding to the gear assembly portion 12 of the camshaft 10 is formed.

Furthermore, the upper and lower gear portions 21 and 22 are provided with bolt holes 26 and 27, each having a two-stage diameter, which are perpendicular to the dividing surface S and directed toward the axis L.

After preparing the camshaft 10 and gear part 20 as described above, a gear upper part 21 and a recess 2 in the lower part 22 are installed in the gear assembly part 12 of the camshaft 10.
3 and 24, and then the upper and lower gears 21 and 2
If the bolts 31 and 32 are inserted into the bolt holes 26 and 27 of 2 and screwed into the screw hole 13 of the camshaft 10, the dividing surface S and the recesses 23 and 24 will come into close contact with each other as described above, and the camshaft 10 and the gear part 20 will be integrated. be converted into

Note that even if the cam surface 14 or the tooth surface 28 is processed prior to assembling the gear portion 20,
Either method may be used, even if the processing is performed after assembly.

In addition, a bolt hole is drilled in place of the screw hole 13 of the camshaft 10, and a long bolt is inserted through the bolt hole 26 of the gear upper part 21, the bolt hole and the bolt hole 27 of the gear lower part 22, and a nut is attached. It can also be tightened.

The camshaft of the present invention has a screw hole or bolt hole perpendicular to the axis of the cast camshaft in the part where the gear is assembled, and a screw hole or bolt hole is formed on the inner periphery of the forged gear part which is divided into two parts parallel to the axis. The semi-cylindrical recessed portion is aligned with the gear set portion of the camshaft, and a bolt is inserted into a bolt hole facing the axis formed in the gear portion and a screw hole or bolt hole of the camshaft, and the gear portion is attached to the camshaft. Since the gear of the cast camshaft shaft is fixed to the part where the gear is assembled, the concave part of the forged gear part, which is divided into two parts parallel to the axis, is aligned with the part where the gear of the cast camshaft shaft is to be assembled, and the bolt hole drilled in the gear part and the camshaft shaft are fixed to each other. By inserting a bolt into a screw hole or bolt hole and fixing the gear part to the shaft, the hardness required for the cam surface and the strength required for the gear part can be adjusted arbitrarily by selecting the material and processing method. For example, sufficient strength can be obtained as a gear for a lubricating oil pump. Further, a screw hole or a bolt hole perpendicular to the axis of the camshaft is drilled in the part of the camshaft where the gear is to be assembled, and the semi-cylindrical recess of the two-part milled gear part is aligned with the gear set part. , A camshaft with a gear that is easy to assemble and align, and is highly accurate, by inserting bolts into a bolt hole drilled in the gear part and a screw hole or bolt hole of the camshaft to fix the gear part to the camshaft. There is an effect that can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a partially longitudinal sectional front view showing an example of a camshaft embodying the present invention, and FIG. 2 is a sectional view taken along the line AA in FIG. 1 showing a gear portion. 10; Camshaft, 11; Cam, 12; Gear assembly part, 13; Screw hole, 20; Gear part, 2
1; gear upper part, 22; gear lower part, 23, 24; recessed part, 26, 27; bolt hole, 31, 32; bolt, S; dividing surface.

Claims (1)

[Scope of utility model registration request] A screw hole or a bolt hole perpendicular to the axis of the cast camshaft is drilled in the part where the gear is assembled, and a semi-cylindrical shape is formed on the inner periphery of the forged gear part which is divided into two parts parallel to the axis. aligning the concave portion with the gear setting portion of the camshaft;
A camshaft in which the gear part is fixed to the shaft by inserting bolts into a bolt hole facing the axis of the gear part and a screw hole or bolt hole of the camshaft.