JPH0569333A - Manufacture of grinding wheel - Google Patents

Abstract

PURPOSE:To prevent the eccentric fitting of a grinding wheel to a bracket to improve grinding accuracy of a workpiece. CONSTITUTION:Through holes 11, into which bolts threadely engaged with a bracket integrated with a motor rotation shaft can be inserted without play, are drilled first in a base metal 8, and then the outer-diameter dimension, a fitting hole 12, and a grinding part 8a of the based metal are worked in prescribed dimensions with the through holes 11 as reference. This causes the inevitable conformity of both center lines of the bracket and a grinding wheel 9 when the grinding wheel 9 after manufacturing is fixed to the bracket, thereby eliminating deflection of a centerline during rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a grinding wheel used for grinding an engine valve with a grinding machine.

[0002]

2. Description of the Prior Art Poppet type engine valves are usually
After being molded into a valve original product by a pressing process, a heat treatment process, etc., it is finished into a finished product through various machining processes. Among the above-mentioned machining steps, there is a step of removing burrs, black skin, and the like generated in the umbrella portion by the pressing step and processing the umbrella portion to a predetermined size. This processing has traditionally been performed by lathes, but with lathes, the number of workpieces that can be cut with a single cutting tool is limited, and frequent changes of cutting tools do not improve productivity. Since it has various problems such as its high surface roughness and relatively large chips coming out, and its treatment is troublesome, grinding has recently been performed using a grinder, that is, a grinding wheel.

FIG. 3 schematically shows a grinding wheel and an engine valve used for grinding the umbrella portion. (1) is a bracket mounted on a rotary shaft of a motor (not shown) and integrally rotated. , (2) is a grinding wheel having a substantially disc shape.

The grinding wheel (2) is provided with a curved grinding portion (2a) for grinding the umbrella back portion (4a) of the engine valve (4) on one side surface side of the outer peripheral end of the base metal (3), Moreover, CBN is added to this grinding part (2a).
(Cubic boron nitride) Abrasive grains (G) are fixed by plating or the like.

In the grinding wheel (2), a large-diameter mounting hole (2b) formed in the center is fitted into the support shaft (1a) of the bracket (1), and then the mounting hole (2b) is surrounded. By bolting the bolts (5) inserted through the plurality of through holes (2c) that are drilled toward the plurality of female screw holes that are drilled in the annular flange portion (1b) of the bracket (1), It is fixed integrally.

The engine valve (4) has a shaft (4a) whose upper and lower rollers are gripped by a gripping device (not shown).
The umbrella back part (4b) is ground by being supported so as to rotate in the same direction as (2), and by feeding the grinding wheel (2) to the right.

When the back surface of the umbrella (4b) is ground on a certain number of workpieces, the grinding of the valve face portion (4c) and the margin portion (4d) is carried out by a grinding wheel (not shown) for that purpose. Are sequentially mounted by attaching the brackets to the bracket (1).

In such a grinding process, since the grinding accuracy of the engine valve (4) after processing is largely influenced by the manufacturing accuracy of the grinding wheel (2), it is necessary to increase the dimensional accuracy of each part.

[0009] In particular, since the grinding wheel using CBN abrasive grains has a large number of workable works, there is a possibility that a large number of defective products will be produced if working is performed in a state where the dimensions of each part have an error. ..

In the conventional grinding wheel (2), first, the outer diameter dimension of the base metal (3), the grinding portion (2a), and the mounting hole (2b) are first machined into specified dimensions, and then a plurality of through holes ( 2c) is drilled, and finally, CBN abrasive grains (G) are fixed to the grinding portion (2a) by plating or the like.

[0011]

When the outer diameter and the mounting hole (2b) of the base metal (3) are processed first and fixed to the flange portion (1b) of the bracket (1) as in the above-mentioned conventional case. If a plurality of through holes (2c) that will serve as reference holes for
In order to facilitate its attachment / detachment and replacement, the fit between the mounting hole (2b) and the support shaft (1a) is a loose fit.
If a slight error occurs in the size of the through hole (2c) or the machining position, the grinding wheel (2) may be attached to the bracket (1) in an eccentric state.

In this case, since the grinding wheel (2) rotates with a runout, the roundness or the like of the machining surface of the umbrella portion is distorted, and the valve seat (not shown) of the valve face portion (4c). The engine's performance will be adversely affected, for example, the seating ability for the

The present invention has been made to solve the above-mentioned problems, and prevents the bracket from being mounted in an eccentric state, thereby improving the grinding accuracy of a workpiece. It is intended to provide a manufacturing method of.

[0014]

In order to achieve the above object, the method of the present invention is to screw a bracket integral with a rotating shaft of a motor at a position separated from a center of a base having a substantially disk shape by a predetermined dimension. After forming a plurality of through holes through which the mating bolts can be inserted without rattling, with reference to the through holes,
It is characterized in that the outer diameter of the base metal and the grinding portion for grinding the work are processed into specified dimensions, and the abrasive grains are fixed to the outer peripheral surface of the base metal including the grinding portion.

[0015]

According to the method of the present invention, a plurality of through holes, through which a bolt screwed to a bracket integral with a rotating shaft of a motor can be inserted without rattling, are first formed in the base metal, and then the through holes are formed. As a reference, in order to process the outer diameter of the base metal and the grinding portion to the specified dimensions, when the grindstone after manufacturing is fixed to the bracket with the bolts that insert the through holes, the center of the bracket and the grindstone The axes are inevitably aligned and do not cause runout during rotation.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. It should be noted that the same members as those of the above-described conventional example will be described with the same reference numerals. In FIG. 2, the bracket (1)
Is fixed to a tapered rotating shaft (6) of a motor (not shown) with a nut (7), and its supporting shaft (1a) has a grinding wheel manufactured by a method described later, that is, a disk-shaped base. Money
An engine valve (4) having curved surface-shaped grinding portions (8a), (8a) that are line-symmetrical with respect to a line that divides the plate thickness of the base metal (8) into two equal parts, on both outer peripheral edges of (8). ) Umbrella back part (4b) Grinding wheel
(9) is fitted and the pressing plate abutted against the front surface of the grinding wheel (9)
A plurality of bolts (5) for inserting the (10) and the base metal (8) are screwed toward the female screw hole (1c) of the flange portion (1b), so that the grinding wheel (9) has its center. It is mounted with its axis aligned with the central axis of the bracket (1).

Next, a manufacturing procedure of the grinding wheel (9) will be described with reference to FIG. 1 (A) to 1 (D) sequentially show the manufacturing process of the grinding wheel (9). First, as shown in FIG. 1 (A),
A disk-shaped base metal whose outer diameter is slightly larger than the outer diameter of the grinding wheel to be manufactured from a plate material of carbon steel with the required thickness (8)
To produce.

Then, as shown in FIG. 1 (B), the base metal (8)
The bracket (1) is located at a predetermined distance from the center of the bracket.
Through hole (11) with a hole diameter that is aligned with the female screw hole (1c) of the flange part (1b) and that allows the fixing bolt (5) to be inserted without play.
Are drilled at regular intervals (6 in the example).

Then, the base metal (8) shown in FIG.
To a jig that can be held on the chuck of a lathe (all not shown),
After bolting using the through hole (11), attach the jig to the chuck of the lathe and rotate the base metal (8) to support the bracket (1) at the center as shown in FIG. 1 (C). A mounting hole (12) having a size that can be fitted to the shaft (1a) is formed, and the outer diameter dimension and the grinding portions (8a) at both outer peripheral edge portions are each machined to a prescribed dimension.

Finally, the curved grinding part (8) of the base metal (8)
If CBN abrasive grains (G) are fixed to the entire outer peripheral surface including a) by plating or the like, the grinding wheel as shown in FIG. 1 (D) and FIG.
(9) is obtained.

As described above, the bracket (8) is attached to the base metal (8).
When the through hole (11) for fixing to the flange portion (1b) of (1) is first drilled and the mounting hole (12) and the outer peripheral surface are machined to the specified dimensions with reference to the through hole (11), Grinding wheel after manufacturing (9)
As shown in Fig. 2, attach the bracket with the bolt (5).
When fixed to the flange portion (1b) of (1), the bracket (1) and the grinding wheel (9) are accurately positioned, and the bracket (1) or the rotary shaft (6) of the motor and the grinding wheel (9) The central axes of the two will necessarily be aligned.

Therefore, there is no fear that the grinding wheel (9) will rotate due to runout, and the accuracy of grinding the engine valve (4) can be improved. In addition, in the above embodiment, the mounting hole (12) for fitting the support shaft (1a) of the bracket (1) is formed at the center of the base metal (8), but the support shaft (1a) And the thickness of the flange (1b) is adjusted to the front end face of the bracket (1).
If the grinding wheel (9) is increased to a position flush with (the right end surface in FIG. 2) and the grinding wheel (9) is bolted to the front end surface, the step of processing the mounting hole (12) can be omitted.

Also, a through hole (11) through which the bolt (5) is inserted.
May be a stepped hole as in the conventional example, and in this case, the holding plate (10) can be eliminated. The method of the embodiment is a grinding wheel for grinding the umbrella back portion (4b) of the engine valve (4).
In the case of manufacturing (9), the valve face portion (4c) having a tapered outer peripheral surface and the grinding wheel for grinding and the margin portion (4d) having a substantially outer peripheral surface for a grinding wheel as described above are also used. It can be manufactured in the same manner as.

Of course, the present invention is not limited to a grinding wheel for engine valve grinding.

[0025]

According to the present invention, the base metal is first provided with a through hole for mounting on the bracket, and the outer diameter dimension and the like are machined with reference to the through hole, so that the bracket is mounted eccentrically to the bracket. There is no fear that the grinding wheel will run out, and the grinding accuracy of the workpiece can be improved.

[Brief description of drawings]

FIG. 1 is a front view showing an embodiment of the present invention in process order.

FIG. 2 is a vertical cross-sectional view showing an example of mounting on a bracket of a grindstone wheel which is also manufactured.

FIG. 3 is a vertical cross-sectional view of a main part showing an example of attachment to a bracket of a grinding wheel manufactured by a conventional method.

[Explanation of symbols]

(1) Bracket (1a) Support shaft (1b) Flange part (1c) Female screw hole (4) Engine valve (workpiece) (4a) Shaft part (4b) Umbrella back part (4c) Valve face part (4d) Margin part ( 5) Bolt (6) Rotating shaft (7) Nut (8) Base metal (8a) Grinding part (9) Grinding wheel (10) Holding plate (11) Through hole (12) Mounting hole (G) CBN abrasive grain

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B24D 18/00 7234-3C

Claims (1)

[Claims] 1. A plurality of through holes, through which a bolt screwed into a bracket integral with a rotation shaft of a motor can be inserted without play, at a position spaced apart from a center of a base metal having a substantially disk shape by a predetermined amount. After that, with reference to the through-hole, the outer diameter of the base metal and the grinding portion for workpiece grinding are processed into specified dimensions, and abrasive grains are fixed to the outer peripheral surface of the base metal including the grinding portion. Manufacturing method of grinding wheel.