JPH068021A - Machining of sheet surface of cylinder head and valve guide hole - Google Patents

Abstract

PURPOSE:To provide roundness of a valve sheet surface and concentricity of the valve sheet surface and a valve guide hole with high precision. CONSTITUTION:A valve guide hole 7 of a cylinder head 5 is reamed, and in the state where a reamer 31 is inserted into the valve guide hole 7, a valve surface 6 is cut and processed. Additionally, before the aforementioned valve guide hole 7 is reamed, the valve sheet surface 6 is roughly processed, and after the aforementioned reaming, in the state where the reamer 31 is inserted into the valve guide hole 7, the aforementioned valve sheet surface 6 is finished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for processing a seat surface and a valve guide hole of a cylinder head used in an engine of an automobile or the like.

[0002]

2. Description of the Related Art Generally, in a cylinder head of an engine, high machining accuracy is required for the roundness of the valve seat surface and the concentricity of the valve seat surface and the valve guide hole. This is to prevent energy loss due to gas leakage or the like when a valve provided slidably in the valve guide hole closes the valve seat surface so that no gap is created.

Conventionally, in order to finish the valve seat surface and the valve guide hole with high precision, for example, as shown in FIG.
It was processed with the device shown in. In this processing apparatus, a valve seat surface processing cutting blade 2 and relief surface processing cutting blades 3a and 3b are respectively provided on the outer peripheral portion of the tip of the rotary shaft 1 in three equal parts. The rotary shaft 1 is rotated by a drive mechanism (not shown) and reciprocates in the axial direction. Further, a reamer 4 is spline-coupled with the central hole 1a of the rotary shaft 1 so as to rotate integrally therewith, so that the reamer 4 can reciprocate in the axial direction separately from the rotary shaft 1. Has become.

In order to machine the valve seat surface 6, the relief surfaces 8 and 9 and the valve guide hole 7 of the cylinder head 5 shown in FIG. 7 with the above-mentioned machining device, the rotary shaft 1 is rotated and moved forward to the left in FIG. By doing so, each cutting blade 2, 3a,
At 3b, the valve seat surface 6 and its relief surfaces 8 and 9 are cut at the same time. In this way, when the valve seat surface 6 is finished, the rotary shaft 1 is retracted, and this time the reamer 4 is rotated and advanced to process the valve guide hole 7.

[0005]

However, when the valve seat surface 6 is cut as described above, a large load is applied to the cutting blades 2, 3a, 3b and the rotary shaft 1 bends, so that the valve seat surface is bent. 6 was formed eccentrically from the normal position, and the roundness was poor. Further, since the valve guide hole 7 is reamed separately from the valve seat surface 6, it is difficult to obtain a highly accurate concentricity between the two. In view of the above problems, the present invention provides a method for machining a seat surface of a cylinder head and a valve guide hole, which can finish the roundness of the seat surface and the concentricity of the seat surface and the valve guide hole with high accuracy. With the goal.

[0006]

In order to achieve the above-mentioned object, the present invention cuts a valve seat surface of a cylinder head and a relief surface of the valve seat surface by a cutting blade attached to a rotary shaft, In a method of machining a valve seat surface of a cylinder head and a valve guide hole for reaming with a reamer provided with a guide hole at the center of a rotary shaft, the valve guide hole is reamed and the reamer is left inserted into the valve guide hole. In this state, the valve seat surface is cut. Also, if the valve seat surface is rough processed before reaming the valve guide hole,
The time for finishing the valve seat surface that guides the reamer can be shortened.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is an overall view of a processing apparatus for processing a valve seat surface and a valve guide hole of a cylinder head by the method according to the present invention. In FIG. 1, reference numeral 11 denotes a rotary drive shaft, which is rotatably disposed on a cylindrical portion 13 of a processing table 12 capable of indexing and feeding on the bed 10 via a bearing 14. A stopper receiving portion 15 is screwed to the tip end surface of the rotary drive shaft 11, and
It is covered with a lid 16. Further, a pulley 17 that is driven in forward and reverse directions by a drive mechanism (not shown) is mounted on the rear end of the rotary drive shaft 11 so that the rotary drive shaft 11 and the pulley 17 rotate integrally via a key 18. Has become. In addition, a through hole 19 is formed in an intermediate portion of the rotary drive shaft 11 in a direction perpendicular to an axis line, and a rear end side of the rotary shaft 20 is exposed.

The swivel shaft 20 is rotatably disposed at the tip end side of the center hole 11a of the rotary drive shaft 11 via a bearing 11b. As shown in FIG. 2, the orbiting shaft 20 is provided with a through hole 20a having an axis B which is eccentric from the axis A of the rotary drive shaft 11 by a distance e. Further, as shown in FIG. 3, a pair of stopper portions 21a and 21b are fixed to the outer peripheral portion of the tip end of the swivel shaft 20. These stopper portions 21a and 21b are brought into contact with the stopper receiving portion 15 of the rotary drive shaft 11 to make contact with the rotary shaft 20.
Is rotated 180 degrees forward and backward.

Further, the tip end surface of the rotary shaft 20 is shown in FIG.
The quill 22 is fixed as shown in FIG. A guide bush 23 is fixed to the front end portion of the quill 22, and a hole 22a having the same diameter as the through hole 20a is formed in the rear end surface thereof.
3a is in communication with the escape hole 22b. Also,
As shown in FIG. 3, the quill 22 is provided with a valve seat surface cutting blade 24 and relief surface cutting blades 25 and 26 at equal intervals, as shown in FIG. Further, the rear end of the swivel shaft 20 is a helical spline shaft 27 as shown in FIG.

At the rear end side of the central hole 11a of the rotary drive shaft 11, a sliding member 28 is arranged so as to be reciprocally movable in the axial direction by a feeding mechanism (not shown). A helical spline nut 29 that is screwed into the helical spline shaft 27 is fixed to the tip of the sliding member 28. When the sliding member 28 is moved leftward in FIG. 1, the turning shaft 20 moves counterclockwise in FIG. 3 through the nut 29 and the shaft 27 until the stopper portion 21a abuts on the stopper receiving portion 15. If the stopper portion 21b is rotated to the right in FIG.
It is designed to rotate 180 degrees in the clockwise direction until it comes into contact with 5. The sliding member 28 has a groove 28a.
Is formed, and the key 28b fixed to the rotary drive shaft 11 is positioned in the groove 28a, so that both are integrally rotated.

Reference numeral 30 denotes a feeding shaft, which is the hole 2 of the quill 22.
2a, the through hole 20a of the swivel shaft 20, and the center hole 28c of the sliding member 28 are slidably disposed, and can be reciprocated in the axial direction by a feeding mechanism (not shown). A reamer 31 is screwed to the tip of the feeding shaft 30, and the reamer 31 is slidably arranged in a center hole 23a of a guide bush 23 provided on the quill 22. The axis C of the reamer 31 is the quill 22.
The axis E is eccentric from the axis B, and the rotation position of the rotation shaft 20 can match the axis A of the rotary drive shaft 11. Further, a groove 32 is provided on the outer peripheral portion of the delivery shaft 30 on the tip side.
The key 20b screwed to the tip of the revolving shaft 20 is located in the groove 32, so that both can rotate integrally.

Next, a method of processing the valve seat surface 6 and the valve guide hole 7 of the cylinder head 5 shown in FIG. Prior to this processing, the processing table 12 is centered so that the axis A of the rotary drive shaft 11 coincides with the center of the guide hole 7. First, both relief surfaces 8 and 9 adjacent to the valve seat surface 6 are processed. In this processing, the sliding member 28 is moved leftward in FIG. The swivel shaft 20 swivels the stopper portion 21a shown in FIG. 5 counterclockwise through the nut 29 and the shaft 27 to rotate as shown in FIG. In this position, the axis C of the reamer 31 is located on the side opposite to the axis A of the rotary drive shaft 11 with respect to the axis B of the quill, and the flank cutting blades 25, 26 are Are located on a concentric circle centered on the axis A of the cylinder head 5 and face the relief surfaces 8 and 9 of the cylinder head 5, respectively.

Therefore, the rotary drive shaft 1 is provided via the pulley 17.
When the quill 22 is driven to rotate, the quill 22 passes through the key 28b, the sliding member 28, the nut 29, and the shaft 27, as shown in FIG.
It rotates counterclockwise around the axis A. As a result, the flank cutting blades 25, 26 always rotate at positions facing the flanks 8, 9 of the cylinder head 5. Then, when the working table 12 is advanced in this state, the cutting blades 25 and 26 cut the flanks 8 and 9 of the cylinder head 5.

Next, the valve seat surface 6 is roughly processed. In this processing, the processing table 12 is once retracted and the sliding member 28 is moved to the right side in FIG. The swivel axis 20 is shown in FIG.
The stopper 21b shown in FIG.
As shown in FIG. In this state, the axis A of the rotary drive shaft 11 and the axis C of the reamer 31 coincide with each other, and the valve seat surface processing cutting blade 24 faces the valve seat surface 6. Therefore, as described above, when the rotary drive shaft 11 is rotationally driven, the quill 22 rotates counterclockwise about the shaft center A in FIG. When the processing table 12 is moved leftward in FIG. 1, the valve seat surface processing cutting blade 24 cuts the valve seat surface 6. Due to the machining of the relief surfaces 8 and 9 in this cutting process, the flash generated on the valve seat surface 6 side is removed.

Subsequently, the valve guide hole 7 is processed. In this machining, the machining table 12 is slightly retracted again, but since the axis C of the reamer 31 has already coincided with the axis A of the valve guide hole 7 in the rough machining of the valve seat surface 6, the sliding member 28 Is left as is. Then, as described above, while the reamer 31 is rotated about the axis A, the feeding shaft 30 is moved forward to cut the inner peripheral surface of the valve guide hole 7.

Finally, the valve seat surface 6 is finished. This finishing process is performed with the reamer 31 being inserted into the valve guide hole 7. The cutting edge of the reamer 31 does not perform cutting except for the chamfered portion at the tip. Therefore, if the chamfered portion is projected from the valve guide hole 7 as shown by the chain double-dashed line in FIG. By itself acting as a guide, the quill 32 and the payout shaft 30 are prevented from bending during cutting. Therefore, if the valve seat surface 6 is cut by the valve seat surface processing cutting blade 24 as described above, not only the roundness of the valve seat surface 6 but also the valve seat surface 6 and the valve guide hole 7 are not rounded. The core can also be finished with high precision. In the above-mentioned embodiment, the valve seat surface 6 and the valve guide hole 7 are processed separately, but this processing can be performed simultaneously.

[0017]

As is apparent from the above description, according to the method for machining the valve guide surface and the valve guide hole of the cylinder head according to the present invention, the valve guide hole is reamed and the reamer is formed in this valve guide hole. With it inserted,
Since the valve seat surface is finished, the roundness of the valve seat surface is improved and the concentricity between the valve seat surface and the valve guide hole is improved. Further, by roughing the valve seat surface before the reaming of the valve guide hole, the valve seat surface, which uses the reamer as a guide, can be finished in a short time with a small cutting resistance.

[Brief description of drawings]

FIG. 1 is a front sectional view of a processing apparatus according to this embodiment.

FIG. 2 is a partial cross-sectional view of FIG. 1 showing a processed state of a relief surface.

FIG. 3 is a side view of FIG.

FIG. 4 is a partial cross-sectional view of FIG. 1 showing a processed state of a valve seat surface.

FIG. 5 is a side view of FIG.

FIG. 6 is a partial cross-sectional view of a processing apparatus according to a conventional example.

FIG. 7 is a cross-sectional view in the vicinity of a valve seat surface of a cylinder head.

[Explanation of symbols]

5 ... Cylinder head, 6 ... Valve seat surface, 7 ... Valve guide hole, 8, 9 ... Relief surface, 11 ... Rotation drive shaft, 20
… Swivel axis, 22… quill, 24,25,26… cutting blade,
30 ... Delivery shaft, 31 ... Reamer.

Claims (2)

[Claims] 1. A valve seat surface of a cylinder head and a relief surface of the valve seat surface are cut by a cutting blade attached to a rotary shaft, and reamed with a reamer having a valve guide hole provided at the center of the rotary shaft. In the method of machining the valve seat surface and valve guide hole of the cylinder head,
A method of machining a seat surface of a cylinder head and a valve guide hole, wherein the valve guide hole is reamed, and the valve seat surface is cut while the reamer is inserted into the valve guide hole. 2. A valve seat surface of a cylinder head and a relief surface of the valve seat surface are cut by a cutting blade attached to a rotary shaft, and reamed by a reamer having a valve guide hole provided at the center of the rotary shaft. In the method of machining the valve seat surface and valve guide hole of the cylinder head,
After rough machining the valve seat surface, the valve guide hole is reamed, and the valve seat surface is finished while the reamer is inserted into the valve guide hole. How to machine valve guide holes.