JPH1071514A - Cylinder head machining method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the accuracy in the concentricity of the inner and outer diameter of a valve guide and the valve guide and a valve seat face while performing these machining operations at a low cost. SOLUTION: A finishing machined valve guide 5 is press fitted into a cylinder head 1, and the centers of the valve guide 5 are measured at several portions in the axial direction of the valve guide 5, and the eccentricity quantity of the valve guide 5 to the reference center line of the valve guide is calculated from the measured values, and the posture of the cylinder head 1 or a valve seat cutting tool 9 is corrected according to the eccentricity quantity to align the center lines of the valve guide 5 and the valve seat cutting tool 9 with each other, and a seat ring 6 is cut by the valve seat cutting tool 9 for forming a valve seat face 6a.

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 cylinder head for cutting a seat ring mounted on a cylinder head of an automobile engine.

[0002]

2. Description of the Related Art Intake and exhaust valves used in engines are
It is supported by a valve guide fixed to the cylinder head. The valve section at the tip of the intake / exhaust valve closes the combustion chamber by pressing against the valve seat surface formed on the seat ring. These valve guides and seat rings are required to have high processing accuracy because the combustion chamber must be completely closed during the compression stroke and the combustion / expansion stroke.

Referring to FIG. 5, a method of processing a valve guide and a seat ring will be described. As shown in the figure, a cylindrical valve guide 51 and an annular seat ring 52 are fixed to each cylinder of the cylinder head 50 before machining, corresponding to intake and exhaust valves. In this state,
The cylinder head 50 is placed on a processing table (not shown), and is positioned and fixed by fitting positioning pins 54 into two positioning holes 53 provided at predetermined positions of the cylinder head 50.

On the other hand, in the cutting machine 55, a finishing reamer 57 for finishing the inner peripheral surface of the valve guide 51 is attached to the center of the machining head 56, and the valve seat surface 52a is attached to the seat ring 52. A cutting tool 58 for a sheet surface to be processed is mounted. The cutting machine 55 is provided with a plurality of finishing reamers 57 and seat surface cutting tools 58 in accordance with the number of valves of the cylinder head 50.

At the time of cutting, first, the finishing reamer 57 is rotated and advanced with respect to the cylinder head 50 positioned and fixed on the working table, and the finishing reamer 57 finishes the inner peripheral surface of the valve guide 51. Process. Next, the finishing reamer 57 is retracted and the cutting tool 58 is advanced while rotating.
The valve seat surface 52a is formed by the seat surface cutting tool 58 and finishing is performed. Further, the finishing reamer 57 and the sheet surface bit 58 are provided with the cylinder head 5.
Since the same number of valves as the number of zero valves are mounted on the cutting machine 55, each valve of each cylinder is simultaneously machined with respect to the cylinder head 50.

[0006]

In the above-mentioned processing method,
Since the cylinder head is positioned and fixed by fitting a positioning pin into the positioning hole, if the processing accuracy of the positioning pin or the positioning hole is low, the cylinder head is deviated from its reference position. Positioned. Each cylinder is also positioned so as to be deviated from its reference line, and the positioning accuracy varies. In this state, the valves of the respective cylinders of the cylinder head are simultaneously processed, so that the processing reference lines of the valve guides and valve seat surfaces of the respective valves deviate from the reference lines. If the processing reference line deviates from the reference line, a load is applied to the finishing reamer and the sheet surface bite during processing,
There is a problem that it is difficult to finish the inner peripheral surface of the valve guide and the seat surface of the valve seat with high accuracy.

The cutting machine used in the above-mentioned machining method has a finishing reamer and a cutting tool for a sheet surface. However, a cutting machine equipped with both of them has a complicated structure and is very expensive. is there. In particular, the configuration relating to the finishing reamer is complicated. Moreover, since it is a dedicated machine for each model, it is extremely difficult to divert it to other machines. Therefore, there is a problem that costs for processing equipment and processing tools are high.

Accordingly, an object of the present invention is to improve the accuracy of the concentricity of the inner and outer diameters of the valve guide, improve the accuracy of the concentricity between the valve guide and the valve seat surface, and perform these processes at low cost. An object of the present invention is to provide a method of processing a cylinder head.

[0009]

According to a first aspect of the present invention, there is provided a cylinder head having a seat ring provided on a cylinder head, wherein a valve seat surface concentric with a valve guide is formed using a valve seat cutting tool. First, the center of the valve guide is measured at a plurality of positions in the axial direction of the valve guide, and the inclination angle of the valve guide is calculated from these measured values. Corrected the attitude of the head or the valve seat cutting tool so that the center lines of the valve guide and the valve seat cutting tool coincided with each other, and further, the center lines of the valve guide and the valve seat cutting tool coincided with each other In this state, a cutting process for forming a valve seat surface on the seat ring is performed by the valve seat cutting tool.

According to a second aspect of the present invention, there is provided a method of processing a cylinder head, wherein a valve seat surface concentric with a valve guide is formed on a seat ring provided on the cylinder head. Equipped with a measurement unit for detecting the center of the valve guide and a valve seat cutting tool for cutting the seat ring, and the angle and position of the workpiece can be changed according to the numerical signal from the measurement unit. The cylinder head is supported by a certain work supporting device, and then the center of the valve guide is measured at a plurality of positions in the axial direction of the valve guide by a measuring unit, and the inclination angle of the valve guide is calculated from these measured values. In accordance with the numerical signal based on the tilt angle, the angle and angle of the cylinder head are By correcting the position, the respective center lines of the valve guide and the valve seat cutting tool are aligned with each other, and in the state where the respective center lines of the valve guide and the valve seat cutting tool are aligned, the valve seat cutting tool is used. A cutting process is performed on the seat ring to form a valve seat surface.

According to a third aspect of the present invention, in the method for processing a cylinder head according to the first or second aspect, the valve guide press-fitted into the cylinder head is subjected to finish processing in advance.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 1 indicates a cylinder head. The cylinder head 1 is supported by a work support device 2 that adjusts the support posture of the cylinder head 1 and positions the cylinder head 1. The work supporting device 2
This NC machine is capable of operating on four axes, the θ1 axis, the θ2 axis, the X axis, and the Y axis, and includes an θ1 axis driving unit, a θ2 axis driving unit, an X axis driving unit, and a Y axis driving unit. In FIG. 1, the θ1-axis driving unit, the θ2-axis driving unit, the X-axis driving unit, and the Y-axis driving unit are denoted by reference numerals 20, 21, 22, and 23, respectively.

The θ1 axis driving means 20 is a cylinder head 1
Are arranged along the longitudinal direction of the cylinder head 1.
Is rotated in the θ1 direction in the figure. The θ2 axis driving means 21
The cylinder head 1 is disposed below the cylinder head 1 and rotates in the θ2 direction in the figure. Y-axis driving means 23
Is disposed below the θ2-axis driving means 21 and θ1
The shaft driving means 20, the θ2-axis driving means 21, and the cylinder head 1 are moved in the Y direction in the figure. The X-axis driving means 23
It is arranged below the Y-axis driving means 22, and moves the θ1-axis driving means 20, the θ2-axis driving means 21, the Y-axis driving means 22, and the cylinder head 1 in the X direction in the figure.

As shown in FIGS. 2 (a) and 2 (b), a plurality of cylindrical valve guides 5 for supporting the intake and exhaust valves are respectively press-fitted into the cylinder head 1, and the valve of the intake and exhaust valves is provided. A plurality of annular seat rings 6 whose parts are pressed against each other are mounted. The valve guide 5 is preliminarily finished on its inner peripheral surface, and is finished in a size in consideration of a deformation amount due to press-fitting.

An NC machine having a machining head 7 is disposed at a position substantially facing the valve guide 5 and the seat ring 6. A measurement unit 8 for detecting the center of the valve guide 5 or a valve seat cutting tool 9 for cutting the seat ring 6 can be attached to the machining head 7. At the tip of the measurement unit 8, a probe 8a that can be inserted into and removed from the hole of the valve guide 5 is provided. The controller 10 is connected to the measuring unit 8 for calculating the amount of deviation of the valve guide from the reference center line based on the measurement value measured by the tracing stylus 8a.
The amount of deviation includes an inclination angle and a position shift with respect to the reference center line. Further, in the present embodiment, when measuring the center of the valve guide, the center line of the valve guide is used as a reference, but the reference of the valve guide may be provided other than the center line of the valve guide.

At the tip of the valve seat cutting tool 9,
Seat bite 9a forming valve seat surface 6a
And chamfering cutting tools 9b and 9c for chamfering the front and rear sides of the valve seat surface 6a.

Next, the valve seat surface 6 is attached to the seat ring 6.
The procedure for forming a will be described. First, the finished valve guide 5 is press-fitted into the cylinder head 1 corresponding to the intake / exhaust valve. The seat rings 6 are also attached to the cylinder head 1 corresponding to the intake and exhaust valves. The cylinder head 1 to which the valve guide 5 and the seat ring 6 are attached is supported by the work supporting device 2. The work support device 2 positions the cylinder head 1 at a predetermined reference position, and temporarily fixes and holds the cylinder head 1 at that position.

As shown in FIG. 2A, the measuring unit 8
Is mounted on the processing head 7, the measuring unit 8 is moved on the reference center line of the valve guide 5 to be measured. After the measurement unit 8 moves on the reference center line, the measurement unit 8 is advanced to move the tracing stylus 8a to the valve guide 5.
And measures the center of the valve guide 5 near the entrance of the hole. The processing head 7 advances the measuring unit 8 further, and measures the center of the valve guide 5 near the outlet of the hole by the measuring unit 8 again. These measurements are
Output to the controller 10. The controller 10
The center line of the valve guide 5 is calculated based on the plurality of measured values, and the center line is compared with the reference center line of the valve guide 5 to calculate the amount of deviation from the reference center line. This measurement operation is performed for the valve guides 5 of all the intake and exhaust valves, and the deviation amount data for each valve is stored in the memory in the controller 10.

After the measurement of all the intake and exhaust valves is completed, FIG.
As shown in (b), the valve seat cutting tool 9 is mounted on the processing head 7. After the mounting is completed, the valve seat cutting tool 9 is moved on the reference center line of the valve guide 5 corresponding to the seat ring 6 for processing the valve seat surface 6a. On the other hand, the controller 10 outputs the deviation amount data for each valve to the work supporting device 2. The work supporting device 2 is configured to perform the θ1-axis operation based on the deviation amount data so that the center line of the valve guide 5 corresponding to the seat ring 6 on which the valve seat surface 6a is to be processed coincides with its reference center line. , Θ2 axis, X axis and Y axis are driven to correct the angle and position of the cylinder head 1.

After the correction of the angle and the position of the cylinder head 1, the valve seat cutting tool 9 is sent out toward the seat ring 6 while rotating, and the seat surface cutting tool 9 is rotated.
The valve seat surface 6a is formed by cutting the seat ring 6 by a. As shown in FIG. 3, at the same time when the valve seat surface 6a is formed, the front and rear of the valve seat surface 6a are chamfered (6b, 6c) by the chamfering tools 9b, 9c. The correction of the angle and the position of the cylinder head 1 and the cutting of the seat ring 6 are performed on the valve guides 5 of all the intake and exhaust valves. In FIG. 3,
Reference numeral 15 indicates a valve.

Therefore, since the valve guide 5 which has been subjected to finishing in advance is press-fitted into the cylinder head 1, there is no need to perform finishing after press-fitting, and the inner peripheral surface of the valve guide 5 can be finished with high precision. Further, after the center line of the valve guide 5 is corrected to the reference center line, the valve seat surface 6a is formed on the seat ring 6, so that the center line between the valve guide 5 and the valve seat surface 6a can be coaxial. .

FIG. 4 shows a second embodiment, and this embodiment will be described. In the figure, a cylinder head 1 is
While adjusting the support angle of the cylinder head 1,
It is supported by a work support device 25 for positioning. The work supporting device 25 is an NC machine capable of operating in two axes, the θ1 axis and the θ2 axis, and includes an arm 26 that supports the cylinder head 1, a θ1 axis driving unit 27, and a θ2 axis driving unit 28. The θ1-axis driving unit 27 and the θ2-axis driving unit 28 use a motor (not shown) as a driving source.

The θ1-axis driving means 27 is a cylinder head 1
, And rotates the cylinder head 1 in the θ1 direction in the figure. θ2 axis driving means 28
Is disposed below the arm 26 and rotates the cylinder head 1 in the θ2 direction in the figure.

In FIG. 4, the machining head 30 is attached to a tip arm 32 of a machining center 31 that can be numerically controlled. The machining center 31 has an X-axis and a Y-axis.
This is an NC machine capable of three-axis operation of an axis and a Z-axis, and includes an X-axis driving unit 33, a Y-axis driving unit 34, and a Z-axis driving unit 35.

The X-axis driving means 33 includes a slide rail 33a extending in the direction of arrow X in the figure, a movable table 33b moving on the slide rail 33a, and a driving means (not shown) for moving the movable table 33a. It is composed of The Y-axis driving unit 34 is also configured similarly to the X-axis driving unit 33 along the arrow Y direction in the drawing.
The Z-axis driving means 35 is also in a direction perpendicular to the paper surface (Z direction).
Along with the X-axis driving means 33.

A movable table 33b of the X-axis driving means 33 is provided with a Y-axis driving means 34 movable in a direction orthogonal to the moving direction of the X-axis driving means 33.
The movable table 34a of the Y-axis drive unit 34 is provided with a Z-axis drive unit 35 that can move in directions perpendicular to the respective movement directions of the X-axis drive unit 33 and the Y-axis drive unit 34.

Next, the procedure for forming the valve seat surface 6a on the seat ring 6 will be described. Since the procedure is substantially the same as that of the first embodiment, the differences will be described. First, a center line is calculated for the valve guide 5, and the center line is compared with a reference center line of the valve guide 5 to calculate an amount of deviation from the reference center line, that is, an angle shift and a position shift.

The angular deviation from the reference center line is determined by the θ1 axis driving means 27 and the θ2 axis driving
The correction is made by rotating the cylinder head 1 in the θ1 direction and the θ2 direction according to 8. The positional deviation from the reference center line is determined by the X-axis driving unit 33, the Y-axis driving unit 34, and the Z-axis driving unit 35 of the machining center 31.
The correction is made by moving the cylinder head 1 in the X, Y, and Z directions, respectively.

After the correction of the angle and the position of the cylinder head 1 is completed, that is, after the center line of the valve guide 5 coincides with its reference center line, the seat ring 6 is cut by the seat surface cutting tool 9a to cut the valve seat surface. 6a is formed. The above-described calculation of the deviation amount and the cutting process are individually executed for all the intake and exhaust valves in accordance with a predetermined order.

[0030]

As described above, according to the first aspect of the invention, the finished valve guide is pressed into the cylinder head, and the center of the valve guide is measured at a plurality of positions in the axial direction of the valve guide. The deviation of the valve guide with respect to the reference center line of the valve guide is calculated from these measured values, and the attitude of the cylinder head or the valve seat cutting tool is corrected according to the deviation to thereby adjust the valve guide and the valve seat. Since the center lines of the cutting tool are aligned with each other and the center lines of the valve guide and the valve seat cutting tool are aligned with each other, the seat ring is cut by the valve seat cutting tool. And a valve seat surface concentric with the seat ring. Accordingly, the concentricity of the inner and outer diameters of the valve guide can be maintained with high accuracy, and the inner peripheral surface of the valve guide can also maintain a highly accurate finish. Further, after the center line of the valve guide is corrected to the reference center line, the valve seat surface is finished, so that the valve seat surface can be finished with high accuracy.

According to the second aspect of the present invention, the machining center for processing the cylinder head is equipped with a measuring unit for detecting the center of the valve guide and a valve seat cutting tool for cutting the seat ring.
The cylinder head is supported by a work supporting device whose angle and position can be changed, and the finished valve guide is pressed into the cylinder head, and the center of the valve guide is measured by a measuring unit at a plurality of positions in the axial direction of the valve guide. Each of them is measured, the deviation of the valve guide from the reference center line is calculated from these measured values, and the angle and position of the cylinder head are corrected by the work supporting device in accordance with the numerical signal based on the deviation, thereby obtaining the valve guide and the valve guide. Since the center lines of the valve seat cutting tool are aligned with each other and the center lines of the valve guide and the valve seat cutting tool are aligned, the seat ring is cut by the valve seat cutting tool. A valve seat surface concentric with the valve guide is formed on the seat ring. Therefore, by utilizing the machining center, it is possible to reduce the cost of the processing equipment, and it is possible to divert it to other models, thereby improving versatility.

According to the third aspect of the present invention, since the valve guide press-fitted into the cylinder head is finished, it is not necessary to finish the inner peripheral surface of the valve guide after press-fitting the cylinder guide. In the process of forming the valve seat surface, the finishing reamer on the inner peripheral surface of the valve guide can be eliminated from the cutting machine, thereby reducing the cost of machining equipment and machining tools, and working the finishing reamer. Since a process is not required, productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a front view of a work supporting device according to a first embodiment of the present invention.

FIGS. 2A and 2B are enlarged views of a valve mounting portion and a measurement unit. FIG.
(B) is an explanatory view showing the formation of the valve seat surface.

FIG. 3 is an enlarged cross-sectional view of a seat ring near a valve seat surface.

FIG. 4 is a plan view of a work support device and a machining center, showing a second embodiment of the present invention.

FIG. 5 is a schematic view for explaining a conventional method for processing a valve guide and a seat ring.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder head 2,25 Work support device 5 Valve guide 6 Seat ring 6a Valve seat surface 7,30 Processing head 8 Measurement unit 9 Valve seat cutting tool 10 Controller 20,27 θ1 axis driving means 21,28 θ2 axis driving means 22, 33 X-axis driving means 23, 34 Y-axis driving means 31 Machining center 35 Z-axis driving means

Claims (3)

[Claims] 1. A method of machining a cylinder head, wherein a valve seat surface concentric with a valve guide is formed on a seat ring provided on the cylinder head by using a valve seat cutting tool. The valve guide is measured at a plurality of positions in the axial direction of the valve guide, and the inclination angle of the valve guide is calculated from the measured values, and the posture of the cylinder head or the valve seat cutting tool is corrected according to the inclination angle. Then, the respective center lines of the valve guide and the valve seat cutting tool are matched with each other, and the respective center lines of the valve guide and the valve seat cutting tool are aligned with each other. A cutting process for forming the valve seat surface on the seat ring. Processing method of de. 2. A method for processing a cylinder head, wherein a valve seat surface concentric with a valve guide is formed on a seat ring provided on the cylinder head, wherein a machining center for processing the cylinder head includes: A work supporting device equipped with a measurement unit for detecting the center and a valve seat cutting tool for cutting the seat ring, and capable of changing the angle and position of the work according to a numerical signal from the measurement unit. The cylinder head is supported by the measurement unit, and the center of the valve guide is measured at a plurality of points in the axial direction of the valve guide by the measurement unit, and an inclination angle is calculated from the measured values. According to the work supporting device, correct the angle and position of the cylinder head. The respective center lines of the valve guide and the valve seat cutting tool are aligned with each other, and the respective center lines of the valve guide and the valve seat cutting tool are aligned with each other. A machining method for a cylinder head, comprising performing a cutting process for forming the valve seat surface on a seat ring. 3. The method according to claim 1, wherein the valve guide press-fitted into the cylinder head is subjected to finishing.