JPH06210559A - Centerless grinder for stepped workpiece and method of grinding the same - Google Patents

Abstract

PURPOSE:To grind a large diameter part so as to have a conical surface by improving a centerless grinder for a stepped workpiece so as to solve a problem of slippage caused by a difference in peripheral speed between the large diameter part and small diameter part, thereby it is possible to carry out precise grinding. CONSTITUTION:A grinding wheel 7 for grinding a large diameter part, and a grinding wheel 8 for grinding a small diameter part, are separately provided while a conditioning grind wheel 9 for the large diameter part, and a conditioning grinding wheel 10 for the small diameter part are separately provided. These four grinding wheels are rotated by independent drive mechanisms 11, 12, 13, 14 so that the their peripheral speeds can be controlled. The conditioning grinding wheel for the large diameter part can be eliminated in a certain case. Further, the grind wheel 7 for the large diameter part is moved simultaneously in two directions indicated by the arrows a' and b' to grind the large diameter part of the workpiece which therefore has a conical surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for centerless grinding a stepped workpiece having concentric large-diameter portions and small-diameter portions, and a centerless grinding method.

[0002]

2. Description of the Related Art FIG. 6 shows a conventional example of an apparatus for centerless grinding a stepped cylindrical workpiece 1, (A) is a schematic plan view and (B) is a front view. Since the workpiece 1 has a large-diameter portion and a small-diameter portion, the grinding wheel 2 and the adjusting grindstone 3 are provided with the large-diameter portion and the small-diameter portion, respectively. The work piece 1 is supported by a blade 4,
The large-diameter portion of the adjusting grindstone 3 and the large-diameter portion of the grinding grindstone 2 slide against the small-diameter portion of the workpiece 1 to perform centerless grinding of the small-diameter portion, and at the same time, the small-diameter portion of the adjusting grindstone 3 and the grinding stone. The small-diameter portion 2 slides on the large-diameter portion of the workpiece 1 to perform centerless grinding of the large-diameter portion.

[0003]

In the conventional centerless grinding apparatus described with reference to FIG. 6, a stepped integrated grinding wheel and a stepped integrated adjustment wheel are provided in accordance with the shape of the stepped workpiece. However, it is not possible to independently adjust the grinding wheel peripheral speed for grinding the large diameter portion of the workpiece and the grinding wheel peripheral speed for grinding the small diameter portion. For this reason, the difference in the diameter of the grindstone corresponding to the difference in diameter between the large diameter portion and the small diameter portion of the stepped workpiece causes a peripheral speed difference, which causes an unstable factor during grinding. In particular, since the adjusting grindstone is a member that controls the rotation speed of the workpiece, it is not preferable that slippage occurs between the workpiece and the adjusting grindstone because it adversely affects the processing accuracy. The present invention was made in view of the above circumstances,
An object of the present invention is to provide a technique capable of performing centerless grinding of a large-diameter portion and a small-diameter portion of a stepped workpiece at the same time with high accuracy.

[0004]

A structure of the present invention for achieving the above object will be described with reference to FIG. 1 corresponding to the first embodiment. A grinding wheel 7 for a large diameter portion and a small diameter portion will be described. The grinding wheel 8 for grinding is separately formed, and driven by the driving means 11 and 12, respectively, so that the peripheral speeds of the grinding wheels 7 and 8 can be controlled independently of each other.
Moreover, the adjusting grindstone 9 for the large diameter part and the adjusting grindstone 10 for the small diameter part
And the drive means 13, and
It is rotationally driven by 14, and each adjustment grindstone 9,10
Peripheral speed can be controlled independently. As mentioned above,
It is the basis of the present invention to divide each of the grinding wheel and the adjusting wheel into a part for the large diameter part and a part for the small diameter part, and control the peripheral speed independently, but as an application, for the small diameter part The adjusting whetstone can be omitted. Further, the end surface (a surface orthogonal to the axis or a surface similar to this) of the workpiece is ground by sending the divided large-diameter portion grinding wheel and / or the small-diameter portion grinding wheel in the radial direction. You can also

Further, by moving the large-diameter portion grinding grindstone and / or the small-diameter portion grinding grindstone in the axial direction and the radial direction, the third cylindrical surface other than the large-diameter portion and the small-diameter portion of the workpiece is to be moved. It is also possible to grind (not shown).

[0006]

According to the above construction, the peripheral speeds of the grinding wheel and the adjusting wheel for the large-diameter portion and the grinding wheel and the adjusting wheel for the small-diameter portion can be independently controlled. Centerless grinding can be performed by appropriately adjusting the peripheral speed of the grindstone as desired. Therefore, in FIG.
It is possible to eliminate the peripheral speed difference, which was an instability factor in the conventional centerless grinding machine described above, and to perform high-precision centerless grinding of the large diameter part and the small diameter part of the stepped workpiece at the same time. You can

[0007]

1 shows an embodiment of a centerless grinding apparatus according to the present invention, (A) is a plan view and (B) is a front view. The stepped work piece 1 is supported from below by a blade 4, as shown in FIG. The grinding wheel 7 for centerless grinding of the large diameter portion of the workpiece 1 and the adjusting wheel 9 have a structure in which they are rotationally driven independently of each other by drive mechanisms 11 and 13 as shown in FIG. It is possible to adjust the peripheral speed to any desired value. Further, the grinding wheel 8 for centerless grinding the small diameter portion of the stepped workpiece 1 and the adjusting wheel 10 are
It has a structure in which it is independently driven to rotate by the drive mechanisms 12 and 14, respectively, and can be adjusted to any desired peripheral speed. The large-diameter portion adjusting grindstone 9 and the small-diameter portion adjusting grindstone 10 can be cut and fed as indicated by reciprocating arrows a and b, respectively. Instead of the structure in which the adjusting grindstones 9 and 10 can be cut and fed as described above, the grindstone 7 for the large diameter portion and the grinding stone 8 for the small diameter portion can be cut and fed as indicated by the reciprocating arrows a'and b ', respectively. It may be a different structure. According to the centerless grinding apparatus of the present embodiment configured as described above, the peripheral speeds of the pair of grinding wheels 7 and the adjusting wheel 9 are appropriate for centerless grinding of the large diameter portion of the workpiece 1. While adjusting the peripheral speed to perform centerless grinding of the large diameter portion under appropriate conditions, in parallel with this, the peripheral speeds of the pair of grinding wheels 8 and the adjusting wheel 10 respectively correspond to those of the workpiece 1. It is possible to perform centerless grinding of the small diameter portion under appropriate conditions by adjusting the peripheral speed to be appropriate for centerless grinding of the small diameter portion. By center-grinding the large-diameter portion and the small-diameter portion at the optimum peripheral speeds as described above, both the large-diameter portion and the small-diameter portion can be highly accurately centerless-ground. That is, the instability factor due to the difference in peripheral speed of the grindstone between the large diameter portion and the small diameter portion as described in the conventional apparatus shown in FIG. 2 is eliminated, and the large diameter portion and the small diameter portion of the stepped workpiece are eliminated. It is possible to perform centerless grinding with high precision at the same time as the part.

In the present embodiment shown in FIG. 1, the adjusting grindstone 10 and the grinding grindstone 8 for the small diameter portion can be reciprocated in the axial direction as indicated by reciprocating arrows c and d. According to this structure, when the centerless grinding machine is maintained, the grindstones 8 and 10 for the small diameter portion can be separated from the grindstones 7 and 9 for the large diameter portion, so that the grindstone replacement work can be easily performed. You can As can be easily understood from this action and effect, even if the grindstones 9 and 7 for the large diameter portion can be moved as shown by the reciprocating arrows c ′ and d ′, the same effect (the grindstone can be easily replaced) can be obtained. can get. The movement of each grindstone in the axial direction (reciprocating arrows c, c ′, d, d ′) in FIG. 1 is based on consideration of exchanging the grindstone. Further, the grindstone is moved in the axial direction (traverse). Advanced grinding work such as grinding a conical surface is also possible. This will be described later with reference to FIGS. Further, as described above, when the grindstone is configured to be movable in the axial direction, the center-shaped workpiece having a large diameter portion and a small diameter portion to be centerless ground is separated. It is suitable for non-grinding.

FIG. 2 shows an improved example of the above embodiment, which is an example in which the small diameter cylindrical surface of the valve stem 31a of the internal combustion engine valve 31 and the large diameter conical surface of the valve face 31b are simultaneously machined. While rotating the grinding wheel 8'for a small diameter portion at a fixed position, the adjusting wheel 10 'is cut and fed in the direction of the arrow b, and the small diameter cylindrical surface of the valve stem 31a is centerless ground. Then, the large-diameter portion grinding wheel 7'is provided with a traverse in the axial direction (arrow Y) and a notch in the radial direction (arrow X) at the same time. The large-diameter portion grinding wheel 7'finishes the valve face 31b into a conical surface while moving in the sum E of moments of the Y-direction component and the X-direction component. In this case, by keeping the moving speed in the arrow Y direction (axial direction) and the moving speed in the arrow X direction (radial direction) constant, the combined moving direction (arrow E) can be linearized. ,
By appropriately setting the ratio of the moving speeds in the X and Y directions, the apex angle 2θ of the conical surface of the valve face can be adjusted as desired.

Although not shown, as a further application example of the improved example of FIG. 2, by variably controlling the moving speed in the X direction and the moving speed in the Y direction in association with each other, for example, a paraboloid of revolution, A rotating surface such as a spheroid or a spherical surface (a curved surface obtained as a locus obtained by rotating a plane curve around an axis on the plane) can be ground. FIG. 3 shows a valve grinder constructed by applying the device of the present invention. 7'shown with spots is a large-diameter portion grinding wheel, 8'is a small-diameter portion grinding wheel, and 10'is an adjusting whetstone, each of which is a constituent part described with reference to FIG. Adjusting whetstone 10 '
Is a component member corresponding to the adjusting grindstone 10 for the small diameter part in the embodiment of FIG. 1, and in this example (FIG. 3), the adjusting grindstone for the large diameter part (reference numeral 9 in FIG. 1) is omitted. is there. When carrying out the present invention, in order to increase the versatility of the grinding machine, a large-diameter portion adjusting grindstone may be added to the configuration of FIG.

In the valve grinder of FIG. 3, the small-diameter portion grinding wheel 8'is rotated at a fixed position by the small-diameter portion grinding wheel rotary drive motor 20. The adjusting grindstone 10 'is rotated by an adjusting grindstone rotation drive motor 21 and can be moved in the radial direction (X-axis direction) by the adjusting grindstone cutting motor 22. In this example, the adjusting grindstone 10 'is replaced with the adjusting grindstone traverse motor 27.
It is configured so that it can be moved in the axial direction (Y-axis direction). In addition, similarly for the large-diameter portion grinding wheel 7 ',
It is rotated by the large-diameter portion grinding wheel rotation drive motor 17, and is rotated in the axial direction (Y-axis direction) by the large-diameter portion grinding wheel traverse motor 18 and by the large-diameter portion grinding wheel cutting motor 19 in the radial direction (X It can be moved in the axial direction).
In the figure, 16 is a single-stone dresser for the adjusting grindstone, and 23 is a manual handle for the adjusting grindstone. Further, reference numeral 15 in the drawing denotes a rotary dresser for a grinding wheel, 24 denotes a rotary dressing motor, 2
Reference numeral 5 is a tooling cutting motor, and 26 is a tooling traverse motor. FIG. 4 shows a different embodiment of the centerless grinding apparatus for stepped workpieces according to the present invention. FIG. 4A shows the large-diameter portion, the small-diameter portion and the end surface of the workpiece shown in FIG. FIG. 3B is a plan view showing a state where the cylindrical surface other than the large diameter portion and the small diameter portion is ground. FIG. 5 shows the workpiece in the above embodiment,
FIG. 5 is a side view showing a target shape of a multi-stage shaft-shaped member having a large diameter portion φ ₂ , a small diameter portion φ ₁ , a flange portion, and a cylindrical surface φ ₃ other than the large diameter portion and the small diameter portion. The multi-stage shaft 41, which is the above-mentioned object, is a member that must finish the following five types of surfaces with high accuracy. (A) Small-diameter part cylindrical surface with diameter dimension φ ₁ (3 places) (b) Large-diameter part cylindrical surface with diameter size φ ₂ (2 places) (c) End face i and end face j of flange-shaped part (diameter ψ ₄ ).
(2 places in total) (d) Cylindrical surface of diameter dimension φ ₃ other than the above large diameter portion and small diameter portion, other than the above, ψ ₁ , ψ ₂ , ψ ₃ , and ψ ₄ , normal general tolerance is allowed. It Such a multi-stage shaft 41 (Fig. 5)
The apparatus of the embodiment shown in FIG. 5 configured to finish the grinding is essentially the same as the configuration shown in FIG. 1, and the grinding wheels are a grinding wheel for a large diameter portion 7 ″ and a grinding wheel for a small diameter portion 8 ″. It is divided into two parts, and the rotation is controlled independently, and the feed is controlled independently in the X and Y directions. The adjusting grindstones are the large-diameter part adjusting grindstone 9 ″ and the small-diameter part adjusting grindstone. It is divided into a grindstone 10 ″, and rotation control and feed control can be performed independently of each other. In this example, both of the adjusting grindstones 9 ″ and 10 ″ are always rotationally driven at the same rotation speed, and at the same speed, the X axis Drives by cutting feed in the direction.

First, as shown in FIG. 4 (A), while the adjusting grindstones 9 "and 10" are rotated, the cutting feed is performed as shown by arrows A and B, and the cylindrical surface of the three small diameter portions φ ₁ is used for the small diameter portion. The grinding wheel 8 ″ is used to perform centerless grinding on the cylindrical surfaces of the _two large diameter portions φ ₂ at the large diameter portion grinding wheel 7 ″. At this time, the position of the stopper St is set so that the gap dimension t between the stopper St and the end surface j of the flange-shaped portion becomes equal to the dimension t entered in the target shape of FIG. In the figure, the hatching applied to the left end surface of the stopper St represents a cemented carbide tip attached for wear resistance.

As described above, while the large diameter portion φ ₂ and the small diameter portion φ ₁ are centerless ground, the small diameter portion grinding wheel 8 ″ is NC.
The end surface i of the flange portion is ground while being fed to a predetermined position in the Y-axis direction by control as indicated by arrow D. Thereby, the thickness dimension T and the position dimension t of the flange-shaped portion shown in FIG. 4B can be controlled with high accuracy.

After the grinding of the large-diameter portion φ ₂ and the small-diameter portion φ ₁ , the large-diameter portion grinding wheel 7 ″ is retracted (separated from the workpiece) as shown in FIG. Move the grindstone 8 ″ as shown by the arrow D ′ to a position not facing the small diameter portion φ ₁ and at a position facing the cylindrical surface having the diameter dimension φ ₃ , and feed it by cutting in the radial direction as indicated by the arrow A ′. ,
Centerless grinding is performed on the cylindrical surface other than the large diameter portion and the small diameter portion. In this way, the product having the target shape and the target accuracy shown in FIG. 5 can be finished.

[0015]

As described above, when the method of the present invention is carried out using the apparatus of the present invention, the large diameter portion and the small diameter portion of the stepped workpiece are centerless at the optimum peripheral speeds. Since grinding is possible, it is possible to perform highly accurate perfect circular finishing by the circular forming action peculiar to centerless grinding without causing the problem of slippage due to the peripheral speed difference between the large diameter portion and the small diameter portion. Then, the large-diameter portion of the stepped workpiece can be finished as a cylindrical surface, or as a conical surface or a rotating surface.

Further, as an application thereof, the cylindrical surface and the end surface other than the large diameter portion and the small diameter portion can be finished with high precision.

[Brief description of drawings]

FIG. 1 is a plan view and a front view showing an embodiment of a centerless grinding apparatus according to the present invention.

FIG. 2 is an explanatory view showing an embodiment different from the above and when grinding a stem and a face of a valve for an internal combustion engine.

FIG. 3 is a plan view of a valve grinder constructed by applying a centerless grinding device according to the present invention.

FIG. 4 is an embodiment of a centerless grinding apparatus for stepped workpieces according to the present invention, which is different from the above, in which (A) grinds the large diameter portion, the small diameter portion and the end surface of the workpiece shown in FIG. FIG. 6B is a plan view showing a state where the cylindrical surface other than the large diameter portion and the small diameter portion is ground.

FIG. 5 is a workpiece in the above embodiment, which is a multi-stage shaft shape having a large diameter portion φ ₂ , a small diameter portion φ ₁ , a flange portion, and a cylindrical surface φ ₃ other than the large diameter portion and the small diameter portion. It is a side view which shows the processing target shape of a member.

6A and 6B are a plan view and a front view showing a conventional example of a centerless grinding apparatus for a stepped workpiece.

[Explanation of symbols]

1 ... Workpiece, 2 ... Conventional stepped grinding wheel, 3 ... Conventional stepped adjustment wheel, 4 ... Blade, 5, 6 ... Drive mechanism, 7, 7 ', 7 "... Large diameter Grinding wheel for parts, 8,
8 ′, 8 ″ ... Grinding wheel for small diameter part, 9, 9 ″ ... Adjusting grindstone for large diameter part 10, 10 ″ ... Adjusting grindstone for small diameter part, 1
0 '... adjusting grindstone, 11 ... drive mechanism of grinding wheel for large diameter part,
12 ... Drive mechanism for grinding wheel for small diameter part, 13 ... Drive mechanism for adjusting wheel for large diameter part, 14 ... Drive mechanism for adjusting wheel for small diameter part, 31 ... Valve for internal combustion engine, 31a ... Valve stem, 31b ... Valve face.

Claims (18)

[Claims] 1. A grinding wheel for a large diameter portion having a rotation driving means capable of arbitrarily controlling the peripheral speed, and a grinding stone for a small diameter portion having a rotation driving means capable of arbitrarily controlling the peripheral speed, A large-diameter portion adjusting grindstone having a rotation driving means capable of arbitrarily controlling the peripheral speed, and a small-diameter portion adjusting grindstone having a rotation driving means capable of arbitrarily controlling the peripheral speed are provided. Further, the centerless grinding apparatus for stepped workpieces is characterized in that the four rotary driving means have a structure capable of controlling the peripheral speed independently of each other. 2. At least one of the large-diameter portion grinding wheel and the small-diameter portion grinding wheel has a structure that can be moved in the axial direction of the grinding stone, and the large-diameter portion grinding wheel and The centerless grinding device for stepped workpieces according to claim 1, wherein at least one of the grinding wheels for the small diameter portion has a structure that can be moved in the radial direction. 3. The movement in the axial direction and the movement in the radial direction can be interlocked with each other, and the ratio between the movement speed in the axial direction and the movement speed in the radial direction is kept constant. 3. A centerless stepped work piece according to claim 2, characterized in that either one of the large-diameter portion grinding wheel and the small-diameter portion grinding wheel can be moved along a straight line. Grinding equipment. 4. The structure is such that the ratio of the moving speed in the axial direction to the moving speed in the radial direction can be adjusted to an arbitrary constant value. By adjusting this ratio, a grinding wheel for a large diameter portion and a small diameter The centerless grinding device for stepped workpieces according to claim 3, wherein at least one of the part grinding wheels can be moved along a desired horizontal straight line. 5. The structure is such that the moving speed in the axial direction and the moving speed in the radial direction can be arbitrarily adjusted, whereby at least one of the large-diameter portion grinding wheel and the small-diameter portion grinding wheel is provided. The centerless grinding device for a stepped work piece according to claim 2, wherein the centerless grinding device is capable of moving along a desired horizontal curve. 6. The small-diameter portion grinding wheel is a shaft position fixing structure that is rotationally driven at a fixed position and does not move in either the axial direction or the radial direction. Centerless grinding device for the stepped work described. 7. A large-diameter portion grinding wheel equipped with a rotational drive means capable of controlling the peripheral speed, a small-diameter portion grinding wheel equipped with a rotational drive means capable of controlling the peripheral speed, and a peripheral speed controllable. Stepped machining, characterized by comprising: an adjusting grindstone for a small diameter portion provided with a rotation driving means, and the three rotation driving means having a structure capable of controlling the peripheral speed independently of each other. Centerless grinding machine for objects. 8. A structure in which at least one of the large-diameter portion grinding wheel and the small-diameter portion grinding wheel is movable in the axial direction, and the small-diameter portion grinding wheel is movable in the radial direction. The centerless grinding apparatus for a stepped workpiece according to claim 7, wherein the centerless grinding apparatus has a structure. 9. A large-diameter portion having a structure capable of interlocking the movement in the axial direction and the movement in the radial direction, maintaining a constant ratio of the moving speed in the axial direction to the moving speed in the radial direction. 9. A centerless grinding apparatus for a stepped work piece according to claim 8, wherein the grinding wheel for use in a vehicle can be moved along a straight line. 10. The structure is such that the ratio of the moving speed in the axial direction to the moving speed in the radial direction can be adjusted to an arbitrary constant value, and a grinding wheel for a large diameter portion is desired by adjusting the ratio. The centerless grinding apparatus for a stepped workpiece according to claim 9, wherein the centerless grinding apparatus is capable of moving along a straight line in the direction. 11. The structure is such that the moving speed in the axial direction and the moving speed in the radial direction can be arbitrarily adjusted, whereby the grinding wheel for a large diameter portion can be moved along a desired curve. 9. The method according to claim 8, wherein
Centerless grinding machine for stepped workpieces described in. 12. The small-diameter portion grinding wheel is rotationally driven at a fixed position, and has a shaft position fixing structure that does not move in the axial direction or the radial direction, according to claim 10 or 11. Centerless grinding device for the stepped work described. 13. A method of centerless grinding a workpiece provided with a small diameter portion having a cylindrical surface and a large diameter portion having a conical surface, wherein a cylinder of the small diameter portion is formed by a grinding stone for a small diameter portion and an adjusting grindstone. Along with grinding the surface, centerless grinding of the conical surface of the large diameter portion while simultaneously moving the large-diameter portion grinding wheel in both the axial direction and the radial direction, the stepped workpiece Centerless grinding method. 14. The small-diameter portion grinding wheel is used for grinding the large-diameter portion conical surface while the small-diameter portion grinding wheel is not moved in the radial direction or the axial direction while the conical surface of the large-diameter portion is ground. The centerless grinding method for a stepped workpiece according to claim 13, wherein the position of the rotary shaft of the grinding wheel is fixed. 15. A method for centerless grinding of a workpiece provided with a small diameter portion having a cylindrical surface and a large diameter portion having a rotating surface, wherein a cylindrical surface of the small diameter portion is provided by a grinding stone for a small diameter portion and an adjusting grindstone. While grinding, while simultaneously moving the large-diameter portion grinding wheel in both the axial direction and the radial direction, by controlling the axial movement speed and the radial movement speed of the large-diameter portion grinding wheel, A centerless grinding method for a stepped workpiece, characterized in that the large-diameter portion grinding wheel is moved along a desired curve. 16. The small-diameter portion grinding wheel is used for grinding the large-diameter portion rotating surface while the small-diameter portion grinding wheel is not moved in the radial direction or the axial direction. The centerless grinding method for a stepped workpiece according to claim 13, wherein the position of the rotary shaft of the grinding wheel is fixed. 17. A work piece provided with a large diameter portion having a cylindrical surface and a small diameter portion having a cylindrical surface, and provided with a flange-shaped portion having a larger cross-sectional area than the large diameter portion. In the method of centerless grinding, while adjusting the grinding wheel while rotating and feeding in the radial direction, the grinding wheel for the large diameter portion makes the cylindrical surface of the large diameter portion, and the grinding wheel for the small diameter portion makes the cylindrical surface of the small diameter portion. And grinding the cylindrical surfaces of the large diameter part and the small diameter part,
At least one of the large-diameter portion grinding wheel and the small-diameter portion grinding wheel is moved in a direction parallel to the axis of the workpiece to grind the end face of the flange-shaped portion. Centerless grinding method for attached workpieces. 18. At least one of a grinding wheel for a large diameter portion and a grinding wheel for a small diameter portion after finishing the grinding of the cylindrical surface of the large diameter portion and the small diameter portion and the grinding of the end surface of the flange-shaped portion. Is moved in the axial direction to bring the workpiece closer to the workpiece in the radial direction from a position not facing the ground cylindrical surface, and the cylindrical surface other than the large diameter portion and the small diameter portion is ground. The method for centerless grinding of a stepped work piece according to claim 17.