JPH07314300A - Centerless grinding machine - Google Patents

Abstract

PURPOSE:To correctly grind only the width portion of a grinding wheel at a prescribed position of a shaft part, even in the case where the length of a work is different, by supporting the projection end of the work by a stopper which is shiftable in the work axis line direction and has a contact part which turns, following the turn of the work. CONSTITUTION:The relative interval between a grinding wheel 4 and an adjusting wheel is increased slightly larger than the axis diameter of an engine valve 3. In this state, the shaft part 3a of the engine valve 3 is installed on a plate 15 having a taper. Then, the grinding wheel 4 in revolution and the adjusting wheel are brought into contact with the outer peripheral surface of the shaft part 3a. In this contact, the engine valve 3 shifts to a stopper device 6 side by the thrust acting on the engine valve 3, and the end surface of a bevel part 3b comes in contact with a contact part 14. In this case, also the pressing member 23 of a valve pressing device 16 makes contact with the end surface of the shaft part 3a. Accordingly, the positioning of the engine valve 3 completes, and in this state, the necessary place of the shaft part 3a is ground by the grinding wheel 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a coreless machine used for grinding a shaft portion or a diameter-expanded portion of a work having an enlarged diameter portion (umbrella portion) at one end of the shaft portion, such as an engine valve. Regarding grinders.

[0002]

2. Description of the Related Art An engine valve is finished through various machining processes. Among the machining processes, there is a process for machining a shaft portion or the like with a centerless grinding machine.

FIG. 5 shows an essential part of a conventional centerless grinding machine. The shaft portion (103a) of the engine valve (103) is attached to the rotary shaft (102) of the first motor (101). The grinding wheel (104) for grinding and the adjusting wheel (108) are attached to the rotary shaft (107) of the second motor (106).
Are axially attached to each other, and the shaft portion (103a) of the engine valve (103) is sandwiched between the grinding wheel (104) and the adjusting wheel (108). The axis line of the rotating shaft (107) of the adjusting wheel (108) is slightly inclined so that the umbrella portion (103b) side of the engine valve (103) becomes higher, and the engine valve (103) has a thrust in the axial end direction. To be given. End (103c) of shaft (103a)
Is an axially movable positioning stopper (109)
Abutted against.

When both motors (101) and (106) are rotated in the same direction, the engine valve (103) is positioned by the stopper (109) for positioning.
By abutting with, the shaft is positioned in the axial direction, and the shaft portion (103a) is ground in this state.

[0005]

However, as described above, a thrust force is applied to the engine valve (103) in the axial end direction to bring the end portion (103d) of the shaft portion (103a) into contact with the stopper (109). Let
When the engine valve (103) is ground with the shaft end as a reference,
The following problems occur.

[0006] Generally, the engine valve (103) is formed by hot squeeze forging.
When 03) is molded, the total length tends to vary.

In order to accurately grind the shaft portion (103a) of the engine valve by a prescribed grinding allowance, a predetermined shaft portion (103a)
It is necessary to bring the outer peripheral surface of the grinding wheel (104) into contact with a predetermined portion of and grind by an amount corresponding to the width of the grinding wheel. At this time, when the engine valve (103) is positioned with reference to the end of the shaft portion (103a), the grinding wheel contact with the shaft portion due to the length of the engine valve (103) as shown by the phantom line in FIG. As the position changes, the grinding wheel (104) and adjustment wheel (10
5), or the position of the stopper (109) needs to be adjusted,
When trying to process a large number of engine valves, their productivity becomes extremely low. Also, using two grinding wheels,
When attempting to grind (103a) and the valve face (103d) at the same time, the shaft portion (103a) of the engine valve (103) has a grinding wheel.
Since it is supported in a cantilevered state by the (104) and the adjusting wheel (107), the engine valve (10
A large runout occurs in 3), and not only the valve face portion (103d) but also the machining accuracy of the shaft portion (103a) deteriorates.

The present invention has been made in order to solve the above-mentioned problems. Even if there are variations in the total length of the work, the required grinding allowance is accurately processed without moving the grinding wheel or the like. In addition, it is an object of the present invention to provide a centerless grinding machine capable of preventing runout of a work to be processed.

[0009]

According to the present invention, the above problems can be solved as follows. (1) On the base, a grinding wheel for shaft grinding that rotates at a high speed and an adjusting wheel that rotates at a lower speed than the grinding wheel and can move relative to the grinding wheel are provided, and adjustment is made with these grinding wheels. In a centerless grinding machine in which a shaft portion of a work is sandwiched between outer peripheral surfaces facing each other with a wheel, the outer peripheral surface is ground, and one end side is projected from the grind wheel by the grinding wheel and the adjusting wheel. A thrust force is applied to the held work by the thrust applying means in the projecting direction of the work,
The protruding end of the work is supported by a stopper device that is movable in the work axis direction and that has a contact portion that rotates following the rotation of the work.

(2) In the above item (1), it is assumed that the thrust applying means inclines the axis of the adjusting wheel downward toward the projecting direction of the work.

(3) In the above item (1), the axis of the adjusting wheel is inclined upward toward the projecting direction of the work so that the work car faces the opposite side of the projecting direction. In a centerless grinding machine for applying a thrust, a biasing means having a biasing force larger than the thrust to the work is provided on the side opposite to the projecting direction of the work.

(4) In the above items (1) to (3), an additional grinding wheel for grinding the outer peripheral surface of the projecting end of the work is provided on the base.

(5) In the above items (1) to (4), the abutting portion of the stopper device for positioning is supported by the spherical bearing on the main body of the stopper device.

[0014]

[Operation] The work whose one end side is projected and the shaft portion is sandwiched between the outer peripheral surfaces of the grinding wheel and the adjusting wheel is moved by the thrust applying means.
A thrust force is applied in the projecting direction of the work, and the projecting end is
Since the work is supported by the stopper device that rotates following the rotation direction of the work, the work is ground with the protruding end as a reference. Therefore, even if the length of the shaft portion of the work varies, a predetermined portion of the shaft portion is ground by an amount corresponding to the width of the grinding wheel. Further, since the work is supported in a two-sided holding state, there is no fear of causing runout when grinding the protruding end.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the centerless grinding machine of the present invention will be described below with reference to the accompanying drawings. As shown in FIGS. 1 and 2, the centerless grinding machine of the present invention is a grinding wheel (4) that rotates with a shaft portion (3a) of an engine valve (3), which is a work, being sandwiched between outer peripheral surfaces. And a stopper device that abuts against the adjusting wheel (5) and the end surface of the engine valve (3) on the umbrella portion (3b) side.
(6) and the end face of the shaft part (3a), and the engine valve (3)
The main part is a pressing device (16) for pressing the stopper device (6) side.

The grinding wheel (4) is rotated at high speed in the clockwise direction when viewed from the X direction (FIG. 2) by a motor (not shown) installed on the base (1), and the adjusting wheel (5) is also A motor (not shown) rotates in the same direction at a lower speed than the grinding wheel (4). The adjusting wheel (5) is movable relative to the grinding wheel (4).

The axis of the adjusting wheel (5) is slightly tilted leftward in the drawing from the horizontal state, and the grinding wheel (4) and the adjusting wheel are adjusted.
During rotation of (5), the shaft portion (3a) is ground while applying thrust to the engine valve (3) in the axial direction on the stopper device (6) side. During this grinding, the lower end of the shaft part (3a) of the engine valve (3) has a tapered blade (1
5), and the upper part holds the work (not shown)
By this, jumping out is prevented.

As shown in detail in FIG. 3, the stopper device (6) includes a motor (7) mounted on a support base (2) mounted on the base (1) and an output shaft of the motor (7). The bevel gear mechanism (9) connected to (8) and the block (11) which is moved on the support base (2) in the X direction, that is, the axial direction of the valve by the rotation of the output shaft (10) of the bevel gear mechanism (9). ), A bearing block (12) fixed on the block (11), and a stopper rotatably supported by the bearing block (12).
It comprises a (loader head) (13) and an abutting portion (14) spherically supported by the tip of the stopper (13).

The tip of the output shaft (10) is screwed into the block (11), and when the output shaft (10) is rotated by the rotation of the motor (7), the block (11), that is, the contact portion (14). Moves to a position suitable for valve grinding by the screw feeding action, and comes into contact with the end surface of the umbrella portion (3b) of the engine valve (3) which is given a thrust to the left. As shown in FIG. 4, the contact portion (14) is a stopper.
A spherical bearing is provided by (13), and the end surface of the contact part (14) is
Although it is substantially perpendicular to the axis of the workpiece, it is tiltable within a predetermined angle range with respect to the axis of the valve.

On the axial side of the engine valve (3), that is, on the opposite side of the stopper device (6), there is provided a valve pressing device (16) for applying an auxiliary thrust to the engine valve (3).
This valve pressing device (16) is a support base (2) on the base (1).
Attached to the motor (17) and its motor output shaft (18)
Bevel gear mechanism (19) and bevel gear mechanism (1
Fine movement block (21) screwed to the output shaft (20) of 9), and an elongated pressing member (23) attached to the shaft at the tip of the fine movement block (21) so as to be constantly pressed by the spring (22). It consists of When the motor (17) rotates, the fine motion block
(21), that is, the pressing member (23) moves in the valve axial direction and contacts the end face of the valve shaft portion (3a), and the engine valve (3) is always spring (22) to the stopper device (6) side. ) It is designed to be pressed by the load.

Next, the procedure for grinding the shaft portion (3a) of the engine valve (3) by the centerless grinding machine of the present embodiment having the above construction will be described.

With the relative distance between the grinding wheel (4) and the adjusting wheel set slightly larger than the shaft diameter of the engine valve (3), the shaft portion (3a) of the engine valve (3) is provided with a tapered blade. When the grinding wheel (4) and the adjusting wheel (5) that rotate together after being placed on (15) are brought into contact with the outer peripheral surface of the shaft portion (3a), the engine valve (3) causes the thrust force to act on it. By stopper device
It moves to the (6) side, and the end surface of the umbrella portion (3b) comes into pressure contact with the contact portion (14). At this time, the pressing member (23) of the valve pressing device (16) also contacts the end surface of the shaft portion (3a).

With this, the positioning of the engine valve (3) is completed, and in this state, the required portion of the shaft portion (3a) is the grinding wheel.
It is ground by (4).

After the grinding, the engine valve (3) slightly expands the relative distance between the grinding wheel (4) and the adjusting wheel (5).
The work is discharged by a work supply / discharge device (not shown).

Thus, when grinding the engine valve (3), the end surface of the umbrella portion (3b) is brought into contact with the contact portion (14),
When the engine valve (3) is positioned with reference to the end face of (3b), the end of the grinding wheel (4) on the stopper device (6) side will always be the engine regardless of the length of the engine valve (3). The shaft portion (3a) of the valve (3) comes into contact with a certain position on the side of the umbrella portion (3b), and the shaft portion (3a) ahead of this portion contacts the grinding wheel (4).
Therefore, it is not necessary to correct the position of the grinding wheel (4), the adjusting wheel (5) or the stopper according to the length of the engine valve (3) as in the conventional case.

When the length of the engine valve (3) is longer than the specified dimension, the end portion side of the shaft portion (3a) is not ground, but this portion will be cut in a later step, so this is especially true. No problem.

Next, an embodiment in which not only the shaft portion (3a) of the engine valve (3) but also the valve face portion (3c) of the umbrella portion (3b) is simultaneously ground will be described. At this time, as shown by the phantom lines in FIGS. 1 and 2, an additional grinding wheel (24) for grinding the valve face portion (3c) may be added to the above-described embodiment.

This additional grinding wheel (24) is also rotatable by a motor (not shown), and X and Y on the base (1).
It is provided so that it can move in any direction.

In the conventional centerless grinding machine, the engine valve
Since (3) is supported in a cantilevered state, the valve face part
When attempting to grind (3c) with the additional grinding wheel (24), the load acting during grinding causes eccentricity in the engine valve (3), impairing the roundness of the valve face (3c), and Can not be ground.

On the other hand, like the present embodiment, the valve face portion (3c) is added to the additional grinding wheel (while supporting the end face of the umbrella portion (3b) of the engine valve (3) by the stopper device (6). If the grinding is performed by 24), the engine valve (3) will be ground in the both-supported state, so that the valve face portion (3c) can be accurately finished.

The additional grinding wheel (24) may be pivotally mounted on the rotary shaft of the grinding wheel (4), and the two grinding wheels (24) (4) may be rotated by one motor.

The present invention can also be applied to a centerless grinding machine in which thrust is applied to the engine valve (3) on the side opposite to the stopper device (6). At this time, the spring constant of the spring (22) in the valve pressing device (16) may be made larger than the above thrust. This allows the engine valve
Since the end surface of the umbrella portion (3b) of (3) comes into pressure contact with the contact portion (14), the same operational effect as the above-described embodiment can be obtained.

[0033]

According to the present invention, the following effects can be obtained. (a) Since the work is positioned with reference to the projecting end face of the work, even if the work has different lengths, the predetermined position of the shaft portion can be accurately ground by the width of the grinding wheel. Therefore, it is not necessary to adjust the position of the grinding wheel, the adjusting wheel, or the stopper device each time.

(B) According to the invention described in claim 3, the conventional centerless grinding machine can be used as it is, and the same effect as (a) can be obtained.

(C) According to the invention described in claim 4, the projecting end of the work supported in a double-supported state can be ground with high precision simultaneously with the shaft portion.

(D) According to the fifth aspect of the invention, even if the projecting end of the work is not flat, the abutting portion can always come into contact with the projecting end surface of the work and rotate, and the work can be biased. There is no risk of generating loads.

[Brief description of drawings]

FIG. 1 is a side view showing an embodiment of a centerless grinding machine of the present invention.

FIG. 2 is a plan view showing an enlarged main part of the same.

FIG. 3 is an enlarged cross-sectional view of a main part of a stopper device.

FIG. 4 is an enlarged cross-sectional view of a contact portion of a stopper.

FIG. 5 is a plan view showing a main part of a conventional centerless grinding machine.

[Explanation of symbols]

 (1) Base (2) Support base (3) Engine valve (work) (3a) Shaft part (3b) Umbrella part (protruding end) (3c) Valve face part (4) Grinding wheel (5) Adjusting wheel (giving thrust) Means) (6) Stopper device (7) Motor (8) Output shaft (9) Bevel gear mechanism (10) Output shaft (11) Block (12) Bearing block (13) Stopper (14) Contact part (15) Tapered Blade (16) Valve pressing device (biasing means) (17) Motor (18) Motor output shaft (19) Bevel gear mechanism (20) Output shaft (21) Fine block (22) Spring (23) Addition of pressing member (24) Grinding wheel

Claims (5)

[Claims] 1. A grinding wheel for rotating a shaft portion that rotates at a high speed, and an adjusting wheel that rotates at a lower speed than the grinding wheel and is movable relative to the grinding wheel are provided on a base. In a centerless grinding machine configured to grind the outer peripheral surface of the work by sandwiching the shaft portion of the work between the outer peripheral surfaces facing each other of the adjusting wheel and the adjusting wheel, one end side is ground by the grinding wheel and the adjusting wheel. A thrust force is applied to the work that is further projected and sandwiched by the thrust applying means, and the projecting end of the work is movable in the work axis direction and is rotated by the rotation of the work. A centerless grinding machine characterized by being supported by a stopper device having a contact portion. 2. The thrust applying means controls the axis line of the adjusting vehicle to be a work line.
The centerless grinding machine according to claim 1, wherein the centerless grinding machine is inclined downward in a protruding direction of the blade. 3. A core adapted to impart a thrust force directed to the opposite side of the projecting direction to the work by inclining the axis of the adjusting wheel upward toward the projecting direction of the work. 2. The centerless grinding according to claim 1, wherein a biasing means having a biasing force larger than the thrust to the work is provided on the side opposite to the work protruding direction in the no-grinding machine. Board. 4. The centerless grinding according to claim 1, wherein an additional grinding wheel for grinding the outer peripheral surface of the protruding end of the work is provided on the base. Board. 5. An abutting portion of a positioning stopper device,
The centerless grinding machine according to any one of claims 1 to 4, which is supported by a spherical bearing with respect to the main body of the stopper device.