JPH0744439Y2 - Hole chamfering grindstone device such as the injection hole of the valve body - Google Patents

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial field of application) The present invention is directed to a grindstone for chamfering the periphery of a hole such as an injection port of a valve body which is a component of a fuel injection valve of an automobile engine. Regarding the device.

(Prior Art) A fuel injection valve of an automobile engine is configured, for example, as shown in FIG. In FIG. 3, there is a solenoid coil 3 energized in a pulsed manner by an input from a wiring connector 2 in a housing 1, and this coil 3 is arranged so that a needle valve 5 can reciprocate in a valve body 4. . Reference numeral 6 is an injection port of the valve body 4.
In this fuel injection valve, fuel is pressurized and flows as shown by the arrow.
The needle valve 5 slides by injecting power to the solenoid coil 3 in response to an input signal, and fuel is injected from the injection port 6.

By the way, considering the contact relationship with the needle valve 5 around the injection port 6, so that the fuel injection amount becomes a predetermined air-fuel ratio,
It is necessary to finish it precisely, and at that time, as shown in FIG. 4, the intersection (peripheral portion) 7 between the injection port 6 and the valve seat 8 is a portion that needs to be chamfered so as not to be an edge.

Conventionally, this chamfering process is performed as shown in FIG. That is, the rod-shaped grindstone 8 rotated by a motor (not shown) is covered with a protective cover 9, the conical portion 10 at the tip is used as an exposed grindstone, and the work (valve body) 4 is pressed against the work pressing plate 11 so that the surface of the peripheral portion 7 is covered. It is what you take.
At this time, if the diameter d'of the grindstone protection cover 9 is referred to as 4 mm, the diameter D of the guide hole (see FIG. 4) 12 of the work 4 is 3.98 (0 to -0.02) mm, which is slightly smaller than these. The workpiece 4 and the grindstone 8 are aligned with each other by fitting, and chamfering is performed with good precision.

(Problems to be solved by the invention) However, since the conventional hole chamfering grindstone device performs chamfering using the guide hole of the valve body (work) as a guide of the grindstone, the grindstone protection cover 9 and the guide hole At the time of relative rotation with 12, the abrasive grains on the tip chamfer penetrate into the rotation gap,
There is a problem that the valve guide hole 12 is damaged and the product reliability is deteriorated due to deterioration of sliding guide with the needle valve.

Conventionally, therefore, it has been necessary to clean the grindstone by machining 2-3 times, which causes problems such as reduced productivity and increased cost in maintenance.

This invention, therefore, provides a hole chamfering whetstone device for a valve body nozzle or the like that does not reduce the reliability of a workpiece as a product and does not reduce the productivity.
The purpose is to solve the above problems.

[Means for Solving the Problem] (Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention has a motor, a tip that is rotated by the motor, is formed in a conical portion, and has a diameter smaller than that of the work guide hole. A rod-shaped grindstone and a work pressing plate having a counterbore surface through which the grindstone penetrates from the motor side to press the work on the other side, and the work is rotated by rotating the press grindstone on the counterbore surface of the pressing plate. It is designed to chamfer the hole.

(Operation) The workpiece is brought into contact with the counterbore surface of the plate and is pushed out so as to protrude from the plate and fit into the non-rotating grindstone, and the grindstone is moved forward until the tip portion hits. As a result, the center of the grindstone comes out, so it is rotated there to perform chamfering. Since the rod-shaped part of the grindstone has a small diameter, it forms a large gap with the guide hole of the work, and therefore,
The abrasion powder and abrasive grains of the grindstone will not clog the gap.

(Embodiment) An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

First, the overall configuration will be described with reference to FIG. The same parts as those of the conventional one are designated by the same reference numerals. A slide unit 14 and a work pressing plate 11 are fixed on a table 13.
An air motor 15 is slidably mounted on the guide of the slide unit 14, and the motor 15 can be moved left and right against the spring 17 by the rotation of the bolt 16 or by its urging force.

The motor 15 holds the grindstone 8 by a clamper 18.

As shown in FIG. 2, the work pressing plate 11 has a hole 20 through which the grindstone 8 penetrates from the motor side, and a counterbore surface 19 is provided on the counter motor side. The center of the hole 20 and the spot facing surface 19 is on the center line 0-0 of the grindstone 8, and the circumference of the spot facing surface 19 has the same diameter as the anti-injection surface of the work 4, that is, the pressing surface.

The grindstone 8 has a rod-shaped portion covered with a protective cover 9, and the grindstone portion is exposed only at the tip conical portion 10. Further, the diameter d provided with the rod-shaped protective cover 9 is a guide hole for the work 4.
The diameter is smaller than the diameter D of 12. If the diameter D of the work guide hole 12 is 4 mm as in the above example, the diameter d is preferably 3.5 mm.

Next, the operation of the above embodiment will be described. The motor 15 holds the grindstone 8 having the above-mentioned configuration by the clamper 18. Motor 15
Has not yet rotated in this state. And the whetstone 8
Is pushed out from the pressing plate 11. Hold the work 4 by hand as shown in FIG. 1 and press it so that the counterbore surface 19 of the plate 11 is aligned. Then, loosen the bolt 16 to remove the motor 1
5. The clamper 18 and the grindstone 8 are moved to the work 4 side by the urging force of the spring 17. And the tip cone part 10 of the grindstone 8
Touches the peripheral edge portion 7 of the nozzle 6 of the work 4. This state can be determined by, for example, whether the tip of the grindstone 8 can be seen from the nozzle 6. By doing so, the whetstone 8 and the work 4 are aligned on the center line 0-0,
Misalignment can be prevented. Then, when the motor 15 is rotated,
By the rotation of the grindstone 8, the tip conical portion 10 chamfers the peripheral edge portion 7, and a predetermined chamfering process can be performed.

Even if abrasive grains are generated during the chamfering process, the gap between the grindstone 8 and the work guide hole 12 is as large as 0.25 mm, so that they do not get caught between the two that are relatively rotating. Therefore, the needle guide hole 12 of the work 4 is not damaged, and the reliability of the work product is not deteriorated. Therefore, cleaning as a maintenance of the grindstone is not necessary so much, so that the productivity can be improved and the product cost can be reduced.

[Advantage of the Invention] As described above, according to the present invention, the chamfering grindstone of the hole of the work such as the injection hole of the valve body can be processed without damaging the work guide hole. It is possible to reduce the manufacturing cost and to prevent the cost increase of the work product.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially cutaway overall front view showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of an essential part of FIG. 1, and FIG. 3 is a valve as a work. FIG. 4 is a cross-sectional view of a fuel injection valve including a body as a component, FIG. 4 is an enlarged cross-sectional view of an injection port portion of a valve body, and FIG. 1 ... Housing 2 ... Wiring connector 3 ... Solenoid coil 4 ... Valve body (work) 5 ... Needle valve 6 ... Injection port 7 ... Chamfered part (peripheral part) 8 ... Whetstone 9 ... Protective cover 10 ... Conical tip 11 ... Work pressing Plate 12 ... Guide hole 13 ... Table 14 ... Slide unit 15 ... Air motor 16 ... Bolt 17 ... Spring 18 ... Clamper 19 ... Counterbore 20 ... Hole

Claims (1)

[Scope of utility model registration request] 1. A motor, a rod-shaped grindstone which is rotated by the motor and has a tip formed in a conical portion and having a diameter smaller than that of a work guide hole, and the grindstone penetrates from the motor side to press the work to the other side. Equipped with a work pressing plate having a counterbore surface to be chamfered, and a chamfering grindstone for a nozzle hole of a valve body or the like, in which a work is chamfered by rotating a pressing grindstone against the counterbore surface of the pressing plate. apparatus.