JPH11216648A - Grinding apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep the flatness and perpendicularity of a surface to be ground even when the axis of rotation of a grinding wheel is not sufficiently parallel to the axis of rotation of a machining head part by using a thin leaf spring as a flexible member. SOLUTION: A machining head part in a grinding apparatus comprises machining head 2, a holding member comprising a leaf spring 3 as a soft and flexible member, a sealing plate 4 and a nozzle holder 5, a leaf spring holder 7 to support these components, an air port 8 for suction and pressurization, and a bearing cover 9 containing a bearing. The leaf spring 3 is formed of a metallic plate, and very thin and flexible, and the thickness of the leaf spring 3 is 0.05 mm in this embodiment. Even when the axis of rotation of the machining head part is slightly inclined to that of the grinding part, the angle of inclination θ between the axis of rotation of the machining head part and the axis of rotation of the grinding part is absorbed by the leaf spring 3, and an end face of the nozzle 10 can be horizontally pressed against the grinding surface of a grinding wheel 11. Grinding can be achieved with excellent accuracy while keeping the flatness and perpendicularity of the nozzle end face.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for processing precision parts, and more particularly to a grinding apparatus suitable for grinding a nozzle end face of an electromagnetic fuel injection valve.

[0002]

2. Description of the Related Art An example of a conventional grinding apparatus for precision parts is disclosed in Japanese Patent Application Laid-Open No. Hei 6-320414. There is a method in which a workpiece is pressed against a polishing member by using a highly rigid plate (hereinafter referred to as a first conventional technique).

As an example for controlling the amount of processing, a displacement detecting section and a detector are arranged inside a processing head section as described in JP-A-9-57613, and a laser beam is emitted from the displacement detecting section. There is a method of measuring the distance between the displacement detection unit and the detector to detect the amount of displacement when the workpiece is machined (hereinafter referred to as a second conventional technique).

[0004]

In the first prior art described above, since the workpiece is pressed against the grinding wheel using a highly rigid plate, it cannot be pressed against the ground surface of the grinding wheel flexibly. However, when used on a workpiece that has a flatness or squareness on the surface to be ground from the beginning, the parallelism between the rotation axis of the grinding wheel and the rotation axis of the workpiece does not appear. The accuracy of the flatness and squareness of the member may be reduced.

In the second prior art, since the displacement detector and the detector are arranged inside the processing head, the processing head becomes large.

Further, in the second prior art, since a very thin wafer is used as a member to be processed, the position of the detector may be shifted even if the ground surface of the grinding wheel and the ground surface of the wafer are not parallel. Because there is almost no, the reflected light of the laser can be detected.

However, in the present invention, the nozzle of the electromagnetic fuel injection valve is used as a workpiece, and when the thickness of the wafer is compared with the height of the nozzle, the nozzle is much higher. Therefore, when a detector is used for the nozzle, if the degree of parallelism between the grinding surface of the grinding wheel and the end surface of the nozzle is different, the position of the detector is shifted, and detection is not possible even if laser light is reflected.

[0008]

In order to solve the above-mentioned problems, a grinding apparatus according to the present invention uses a thin leaf spring to press a ground surface of a workpiece to a ground surface of a grinding wheel. Even if the axis of rotation of the grinding wheel and the axis of rotation of the processing head are not sufficiently parallel, the surface to be ground can be pressed against the surface of the grinding wheel flexibly, and the flatness and squareness of the surface to be ground can be maintained. Is now available.

However, when the leaf spring is made thinner, the elastic force of the leaf spring becomes smaller, and the force for pressing the workpiece to the grinding surface of the grinding wheel also becomes smaller. Therefore,
By introducing the compressed air into the processing head, the reduced pressing force can be compensated. Therefore, by using the pressure of the compressed air, the pressure is uniformly applied to the leaf spring, and the workpiece can be pressed with a uniform pressing force against the grinding surface of the grinding wheel.

Further, since the pressure of the compressed air is used to press the surface to be ground against the grinding wheel, the leakage of the compressed air is prevented by using a sealing plate inside the leaf spring. Further, by controlling the pressure of the compressed air, the pressing force can be changed, and a grinding amount corresponding to the pressing force can be obtained.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view of a main part of a nozzle end surface grinding apparatus according to an embodiment of the present invention. The processing head unit 1 includes a processing head 2, a holding member 6 including a leaf spring 3 as a flexible member, a sealing plate 4, and a nozzle holder 5, a leaf spring retainer 7 for supporting them, and an air port for suction and pressurization. 8 and a bearing cover 9 containing a bearing. The processing head 2 is divided into upper and lower parts and connected by a bearing cover 9. Here, the leaf spring 3 may be made of any material as long as it is a flexible member such as a metal plate or a rubber plate.

The suction of the nozzle 10 and the introduction of compressed air for pressing the end face against the grinding surface of the grinding wheel 11 are performed through the air port 8. The processing head 1 is connected to a motor 12, and the processing head 2, the leaf spring 3, the sealing plate 4, the nozzle holder 5 and the leaf spring retainer 7 are rotated by the motor 12 at a constant speed (in this case, 150 rpm). Then, the nozzle 10 is sucked at the center of rotation of the processing head 1. Further, the machining head unit 1 and the motor 12 are mounted on a driving device 13 that moves linearly.
As a result, the processing head 1 linearly moves in the direction of the axis of rotation of the processing head 1.

On the other hand, the grinding wheel 11 is connected to a motor 12 to constitute a grinding section 15, and the grinding wheel 11 is rotated by the motor 12 at a constant rotation speed (in this case, implemented at 90 rpm).
Then, the processing head unit 1 and the grinding unit 15 are arranged in a state where their respective rotation axes are offset in the rotation axis direction,
The linear movement of the driving device 13 brings the end face of the nozzle 10 into contact with the grinding surface of the grinding wheel 11.

Next, the step of grinding the nozzle end surface will be described. First, the processing head unit 1 that sucks and holds the nozzle 10 is linearly moved by the driving device 13 to a position where the end surface of the nozzle 10 contacts the grinding surface of the grinding wheel 11. When the end surface of the nozzle 10 comes into contact with the grinding surface of the grinding wheel 11, compressed air is introduced through the air port 8 to apply a pressure corresponding to a target grinding amount to the leaf spring 3 from the inside of the processing head 1.

The term "pressure with respect to the target grinding amount" as used herein means "to rotate the processing head 1 and the grinding wheel 11 during a certain period of time to grind the nozzle 10 by the target grinding amount.
The pressure of the compressed air required to press the end face of the nozzle 10 against the grinding surface of the grinding wheel 11 ”.

Then, the processing head 1 is passed through the air port 8.
While pressing with pressure against the target grinding amount from inside the
The end face of the nozzle 10 is ground by rotating the processing head unit 1 and the grinding wheel 11 at a constant rotation speed for a predetermined time. The combination of the rotation relations at the time of grinding is as follows: when only the processing head unit 1 rotates, when only the grinding unit 15 rotates, when both the processing head unit 1 and the grinding unit 15 rotate, the processing head unit 1 There are various cases such as a case where the grinding wheel 11 is rotated while rotating, and the present invention can be applied to any combination.

After the grinding is completed by rotating for a certain period of time, the nozzle 10 is sucked again through the air port 8, and the driving device 13 moves the nozzle 10 to the original position, thereby completing the grinding. Next, a description will be given with reference to FIG. FIG. 2 is a schematic cross-sectional view of a main part showing a working state in the cross-sectional view of FIG.

As described above, the leaf spring 3 is very thin and flexible, and the thickness of the leaf spring 3 was set to 0.05 mm this time.
Therefore, even if the rotation axis of the processing head unit 1 and the rotation axis of the grinding unit 15 are slightly inclined as shown in FIG. It can absorb and press the end face of the nozzle 10 horizontally against the grinding surface of the grinding wheel 11.

However, since the pressing force of the leaf spring 3 is reduced by making the leaf spring 3 thinner, compressed air is introduced from the air port 8 to apply pressure to the leaf spring 3. Since the sealing plate 4 is attached to the leaf spring 3 so that no compressed air leaks, a uniform pressure is applied to the leaf spring 3 by the compressed air, and the uniform pressure causes the end face of the nozzle 10 to be ground. The grindstone 11 is pressed against the ground surface with a constant force.

Next, a description will be given with reference to FIG. FIG. 3 is a graph showing a relationship between the grinding amount (μm) of the nozzle end face and the pressure (kg / cm ² ) of the compressed air when the predetermined time is set to 15 seconds at the pressure with respect to the target grinding amount. As shown in the figure, there is a proportional relationship between the grinding amount of the nozzle end face and the pressure of the compressed air. Not only when the processing time is 15 seconds as in this case, but also when the processing time is different Is obtained. Therefore, the processing head 1 and the grinding wheel 11
The grinding amount of the nozzle 10 can be controlled by controlling the pressure of the compressed air while keeping the rotation speed and the processing time of the nozzle constant.

[0021]

According to the present invention, the flatness and the squareness of the nozzle end surface are maintained by using a leaf spring and compressed air when pressing the nozzle end surface of the electromagnetic fuel injection valve against the grinding surface of the grinding wheel. The effect of high-precision grinding can be obtained.

Further, by controlling the pressure of the compressed air, the grinding amount of the nozzle end surface can be easily controlled.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a main part of a grinding device shown as an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view of a main part showing a working state in the cross-sectional view of FIG.

FIG. 3 is a graph showing a relationship between a grinding amount of a nozzle end face and a pressure of compressed air.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Processing head part, 3 ... Leaf spring, 4 ... Sealing plate, 8 ... Air port, 10 ... Workpiece (nozzle), 11 ... Grinding stone, θ ...
The angle between the processing head part rotation axis and the grinding wheel rotation axis.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takuya Sawada 2520 Odaiba, Hitachinaka-city, Ibaraki Pref.

Claims (4)

[Claims] 1. A workpiece is placed on a grinding wheel and covered with a processing head, and compressed air is introduced into the processing head to press the workpiece, and at least either the grinding wheel or the workpiece is rotated. An apparatus for grinding a workpiece by means of a grinding device, wherein a tip end of the processing head and the workpiece are air-tightly connected by a flexible member. 2. The grinding device according to claim 1, wherein a leaf spring is used as the flexible member. 3. The grinding device according to claim 1, wherein a rubber plate is used as a sealing plate for airtightness. 4. The grinding apparatus according to claim 1, wherein the amount of grinding of the workpiece is controlled by changing the pressure of the compressed air.