JPH06246608A - Method and device for centerless grinding - Google Patents

Abstract

PURPOSE:To improve the production efficiency while high circularity of a work is secured by controlling the work supporting condition and the direction of grinding-cutting. CONSTITUTION:In the centerless grinding, the maximum circularity of a work W is secured by setting the angle GAMMA between the line connecting the axis OC of a regulating wheel C and the axis O of the work W and the horizontal line passing the axis O of the work W to the center-height corresponding angle which is approximately equal to the optimum value of the center height angle in a geometrical manner. In addition, the center height angle GAMMA remains unchanged even when the axes OG, OC approach the side of the work W according to the decrease of wear of the outer diameter of the grinding wheel G and the regulating wheel C by setting the axis O of the work to be approximately equal to the axis OG of the grinding wheel (where, the center height 0), and as a result, the adjustment of the center height can be dispensed with, and the axis O of the work is maintained at a constant height.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centerless grinding method and an apparatus therefor, and more particularly, to controlling a workpiece supporting state and a grinding cutting direction to maintain a high roundness of a workpiece while abrading a grindstone. The present invention relates to a centerless grinding technique that simplifies the adjustment work of the constituent devices.

[0002]

2. Description of the Related Art In a centerless grinding machine, a workpiece (hereinafter referred to as "workpiece") W generally has an axis O which is an axis O _G of a grinding wheel _G (strictly speaking, an axis). It is supported on the receiving plate (blade) B so as to be higher than the horizontal line connecting the center O _G and the axis O _c of the adjusting wheel C by a predetermined dimension h, that is, with the center height h, and in this state, the grinding wheel G or The adjusting wheel C is cut into the work W side, and the outer peripheral surface of the work W is ground.

By the way, the roundness of the workpiece W to be ground is determined by the center height angle γ produced by setting the center height h.
(Represented by the equation below with reference to FIG. 9),

[0004] γ = π-φ = β + α ( although, [pi: pi (rad) phi: angle linear OO _c is relative linear OO _G beta: linear OO _G makes with the straight line O _G O _c Angle α: angle formed by the straight line OO _c with respect to the straight line O _G O _c )

It is already known that the optimum value γ _{0 of the} height γ of the center of elevation is generally in the vicinity of 7 °. That is, the optimum height angle γ ₀ is strictly determined by taking into consideration various conditions such as the outer diameter dimension of the workpiece W to be actually ground, but in any case, when it is set near 7 °. It has been theoretically and experimentally proved that the highest roundness can be secured.

[0006]

However, the above-mentioned conventional work supporting structure has the following problems.

That is, as shown by the chain double-dashed line in FIG. 9, when the outer diameters of the grinding wheel G and the adjusting wheel C are worn down and become small, the initial position of the shaft center O _G or O _c becomes Inevitably, the work W side is approached and O _G ′ or O _c
It becomes ´.

In this case, if the work W has the same outer diameter, the relative positional relationship between the work W and the receiving plate B is constant, so that the angle β or α is β ′ as shown in the figure. , Α ′ and increase, and as a result, the sum of these, the height angle γ, also increases, and the height angle γ deviates from the above-described optimum height angle γ ₀ and increases,
If this is the case, the desired maximum roundness cannot be obtained.
The changes in the angles β and α, that is, the center of elevation angle γ also occur due to the cutting operation during the grinding process, but it can be considered that this change is within the allowable range for obtaining the maximum roundness.

Therefore, in order to maintain this maximum roundness, it is necessary to maintain the above-mentioned optimum height angle γ ₀ , and for that purpose, the height h must be adjusted. For example, when the initial outer diameter of the grinding wheel G is 400 mm, the initial outer diameter of the adjusting wheel C is 300 mm, and the outer diameter of the work W is 20 mm, the optimum value of the center angle γ is 7 ° (= the optimum center angle γ _In order to obtain ₀ ), the core height h is set to 11.088 mm. Then, the grinding wheel G and the adjusting wheel C are worn out,
When the outer diameters of the respective cores are reduced to 300 mm and 250 mm, the above-mentioned core height angle γ becomes 8.685 °, and in order to maintain this core height angle γ at the optimum value of 7 ° again, the core height h
Needs to be adjusted to 8.94 mm.

However, in the conventional work W support structure described above, when actually adjusting the core height h, the height of the receiving plate B is adjusted.
The heights of the carry-in device and the carry-out device need to be adjusted according to the height of the receiving plate B. The adjustment work is extremely complicated, troublesome and difficult, and the automation and labor saving of the grinding work are significantly hindered, making it difficult to efficiently and stably supply a highly accurate product.

From the above, in reality, there is no prior art that adopts such an adjusting method, and, after all, the heart height h is fixedly kept constant and a certain degree of change (increase) in the heart height angle γ. However, in reality, a grinding method that increases production efficiency even if the roundness is sacrificed to some extent has been adopted.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to ensure a high roundness of a work by controlling a work supporting state and a grinding cutting direction. It is an object of the present invention to provide a centerless grinding method and an apparatus therefor capable of improving production efficiency.

[0013]

In order to achieve the above object, the centerless grinding method of the present invention is such that the work center plate is placed on the work receiving plate so that the center axis of the work is substantially level with that of the grinding wheel. The angle between the straight line connecting the axis of the adjusting wheel and the axis of the work and the horizontal line passing through the axis of the work is geometrically approximately equal to the angle of the height of the heart. , Arrange the adjustment car, and adjust this adjustment car or grinding wheel,
It is characterized in that the shaft center is cut so as to approach in the axial direction of the work, and the cylindrical surface or the end surface of the work is ground.

Further, the centerless grinding apparatus of the present invention executes the above grinding method, and the axis of the work supported on the supporting surface of the receiving plate is substantially the same as the axis of the grinding wheel. The adjusting wheel is set so that it has a height, and the angle between the straight line connecting the axis of the adjusting wheel and the axis of the workpiece and the horizontal line passing through the axis of the workpiece is geometrically almost equal to the center height angle. The adjusting wheel and the grinding wheel are set so as to have a high corresponding angle, and the axes of the adjusting wheel and the grinding wheel are provided so as to be linearly movable relative to each other in the axial direction of the workpiece.

[0015]

[Operation] During centerless grinding, the angle between the straight line connecting the axis of the adjusting wheel and the axis of the work and the horizontal line passing through the axis of the work is geometrically approximately equal to the height Angle) to maintain the substantial center-of-height angle at an optimum value and to secure the highest roundness of the workpiece to be ground.

In addition to this, the outer diameter of the grinding wheel and the adjusting wheel can be reduced by supporting the shaft center of the workpiece so as to be substantially at the same height as the shaft center of the grinding wheel and setting the core height to zero. Even if the initial positions of these shaft centers approach the work side due to wear due to wear over time, there is no change to the optimum value of the above-mentioned core height corresponding angle (substantial core height angle), and as a result, The center of the workpiece is always maintained at a constant height without the need for center height adjustment.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 A centerless grinding machine according to the present invention is shown in FIG. 1. In this centerless grinding machine, a work W has a grinding wheel G, an adjusting wheel C and a receiving plate B.
And a grinding wheel G and an adjusting wheel C are driven to rotate in the direction of the arrow, and the cylindrical outer peripheral surface of the workpiece W is ground.
Further, the work supporting structure as specifically shown in FIG. 2 is provided. 1 is an apparatus bed, 2 is a grinding wheel platform provided on the apparatus bed 1 for rotatably supporting a grinding wheel G, and 3 is a slide base provided on the apparatus bed 1 so as to be reciprocally movable in an arrow direction, Reference numeral 4 denotes a feed screw device for the slide base 3, 5 denotes an adjustment chassis which is provided on the slide base 3 and rotatably supports the adjustment car C, and 6 denotes a receiving plate base which supports the receiving plate B. .

In the above work supporting structure, the receiving plate B
Is set and arranged so that the axis O of the work W supported on the support surface Ba thereof is substantially the same height as the axis O _G of the grinding wheel G (center height h≈0). More specifically, the axis O of the workpiece W
And a straight line OO _G connecting the axis O _G of the grinding wheel G is made horizontal, and the grinding wheel G is movable to the work W side along the horizontal line OO _G. Further, the height of the supporting surface Ba of the receiving plate B can be appropriately adjusted according to the outer diameter dimension of the work W to be supported by adjusting the height of the receiving plate base 6.

In the adjusting wheel C, an angle Γ formed by a straight line OO _c connecting the axis O _{c of} the adjusting wheel C and the axis O of the work W and a horizontal line (extension line of OO _G ) passing through the axis O of the work W is formed. Is geometrically set to a height corresponding angle to the height γ (see FIG. 9). More specifically, the reciprocating direction of the slide base 3 for supporting the adjusting chassis 6 clogging regulating wheel C (see arrow) is parallel to the straight line OO _c, the driving motor 4a of the feed screw device 4 Due to the rotation of the feed screw 4b by the
It is supposed to be able to reciprocate in the _c direction.

The center-height corresponding angle Γ is determined in consideration of various conditions such as the outer diameter of the workpiece W to be actually ground, as in the case of the center-height angle γ. Is the optimum value.

In the centerless grinding machine having the work supporting structure as described above, the grindstone wheel G and the adjusting wheel C are rotationally driven in the arrow direction at predetermined speeds by the driving source (not shown), and the feed is performed. The adjusting wheel C is cut in the work W direction along the straight line OO _c by the screw device 4, and the outer peripheral surface of the cylinder of the work W is ground.

In this case, the relative positional relationship between the grinding wheel G, the workpiece W and the adjusting wheel C, that is, the center-height corresponding angle Γ is always maintained at the optimum value (the optimum center-height corresponding angle) during grinding, and the grinding is performed. The highest roundness of the work W is obtained.

Further, since the center height h of the work W is set to substantially zero, the outer diameter dimensions of the grinding wheel G and the adjusting wheel C become smaller due to wear over time, and these shaft centers O _G , Even if the initial position of O _c approaches the work O side (see O _G ′ and O _c ′ in FIG. 2), the optimum value of the above-mentioned center-height corresponding angle Γ (substantial center-height angle γ) is set. Has not changed at all.

Therefore, there is no need to adjust the center height according to the change in the outer diameter of the grinding wheel G and the adjusting wheel C, and the axis O of the work W can be always maintained at a constant height. As long as the model number of W is not changed, the loading / unloading height of the loading / unloading device (not shown) for the work W need not be changed and corrected, and the centerless grinding machine can be fully automated.

Although the adjusting wheel C is cut in the illustrated example, the present invention has a structure in which the grinding wheel G is cut, such as the grinding wheel G, the work W and the adjusting wheel C.
Of course, it can be applied to other structures having different relative movement relations.

Embodiment 2 This embodiment is shown in FIGS. 3 and 4, and is provided with an adjusting wheel support structure capable of adjusting the above-mentioned center-height corresponding angle Γ, and on the adjusting wheel stand 5 provided on the slide base 3, An elevating table 20 for rotatably supporting the adjusting vehicle C is provided so as to be able to ascend and descend.

The lifting table 20 is linked to a feed screw device 21 installed downward on the adjusting chassis 5.
The rotation of the feed screw 21b driven by the drive motor 21a of the feed screw unit 21, the elevation frame 20, that regulating wheel C is perpendicular to the moving direction of the adjusting chassis 5 (the direction parallel to the reference direction of the straight line OO _c) It is supported so that it can move in any direction. Although not shown, the drive motor 21a
Instead of this, a structure may be adopted in which an operating handle is continuously provided on the upper end portion of the feed screw 21b and the movement adjustment of the lifting platform 20 is manually performed.

Therefore, in FIG. 4, the center-height corresponding angle Γ is shown from its reference value ((reference direction of the straight line OO _c ) to, for example, a two-dot chain line in accordance with various conditions such as the outer diameter dimension of the work W. As described above, fine adjustment to Γ _A (<Γ) or Γ _B (> Γ) may be performed by appropriately moving the adjustment carriage 5 and the lift 20 so that the center of the adjustment car C is O. _CA, so that the move to the O _CB (although, OO _c = O
O _CA = OO _CB ).

Thus, with the center height corresponding angle Γ set to the optimum value (for example, Γ _A ) for the target work W, the adjusting screw C is moved parallel to the straight line OO _c by the feed screw device 4. Is cut in the direction, and the outer peripheral surface of the cylinder of the work W is ground.

In this case, the optimum center-of-height corresponding angle Γ _A will slightly change according to the cutting operation of the adjusting vehicle C.
For example, in FIG. 4, when the axial _center O _cA of the adjusting wheel C moves to O _cA ′, the optimum center-height corresponding angle Γ _A is decreased by ΔΓ _A, but this change amount is as shown in FIG. It is much smaller than the amount of change in the device and well within the allowable range for obtaining the maximum roundness. This also applies to the case where the axial center O _CB of the adjusting vehicle C moves to O _CB 'and the optimum center-height corresponding angle Γ _B increases by ΔΓ _B.

On the other hand, when the outer diameter of the adjusting wheel C becomes smaller due to wear over time and the initial position of the axis O _cA of the adjusting wheel C moves to, for example, the above O _cA ′, the lift table 20 is used. It is possible to easily set the optimum height-correspondence angle Γ _A again by moving a small distance downward. Other configurations and operations are similar to those of the first embodiment.

Embodiment 3 This embodiment is shown in FIG. 5 and FIG. 6, and the cutting operation of the adjusting vehicle C in the direction of the straight line OO _c is automatically controlled by a numerical controller or the like.

A slide base 3 for supporting the adjusting chassis 5.
But with is movable in the horizontal direction, that the work W in the axial O and the grinding wheel axis connecting the O _G straight line OO _G in a direction parallel to G (X axis direction), on the adjusting chassis 5, adjusted An elevating table 20 that rotatably supports the vehicle C is provided so as to be able to elevate.

As in the second embodiment, the lifting table 20 is linked to the feed screw device 21 installed downward on the adjusting chassis 5, and the drive motor 2 of the feed screw device 21 is linked.
By the rotation of the feed screw 21b by the drive of 1a, the lifting platform 20, that is, the adjustment car C is supported so as to be movable and adjustable in a direction perpendicular to the moving direction of the adjustment car platform 5, that is, in the vertical direction (Y-axis direction). .

The drive motors 4a, 21a of the two feed screw devices 4, 21 are concretely servomotors, and like other constituent devices such as the drive sources of the grinding wheel G and the adjusting wheel C, a CNC not shown. Is electrically connected to the device,
The relative movement amount (movement speed) of the adjusting vehicle C in the X-axis and Y-axis directions is drive-controlled at a constant movement ratio.

That is, the CNC device synchronously controls the moving amount (moving speed) of the adjusting chassis 5 in the horizontal X-axis direction and the moving amount (moving speed) of the elevating table 20 in the vertical Y-axis direction. C is a straight line with an optimum center height corresponding angle Γ, that is, its axis O _c is along the straight line OO _c.
It will be cut in the direction.

On the other hand, the outer diameter of the regulating wheel C is decreased by temporal wear, the initial position of the axis O _c is, when it comes to moving for example the O _c 'as shown in FIG. 6 , The adjustment carriage 5 and the lift 2 so that the movement ratio of the adjustment vehicle C in the X-axis and Y-axis directions is kept constant and does not change.
Move 0 respectively. Other configurations and operations are similar to those of the first embodiment.

Example 4 This example is shown in FIG. 7, the mechanical basic structure is exactly the same as that of Example 3, and the center height corresponding angle Γ can be adjusted by the CNC device as in Example 2. It is a thing.

That is, in this example, the center height corresponding angle Γ is set to, for example, Γ depending on various conditions such as the outer diameter of the work W.
_To make a fine adjustment to _C (> Γ), change the setting of the program of the above CNC device to adjust the adjustment chassis 5 and the lift 2
0 is appropriately moved by a minute distance, and the axis O of the adjusting vehicle C is set to the axis O _CC as desired.

However, thereafter, according to these new setting conditions, the moving amount (moving speed) of the adjusting chassis 5 in the horizontal X-axis direction and the moving amount (moving speed) of the lifting platform 20 in the vertical Y-axis direction.
Is controlled synchronously, and the adjusting car C has an optimal center height corresponding angle Γ _C
With this, the work is linearly cut in the W direction.

When the outer diameter of the adjusting wheel C becomes smaller due to wear over time and the initial position of the axis O _cC of the adjusting wheel C moves to the above-mentioned O _cC ′, for example, the third embodiment will be described. Similarly, the adjustment carriage 5 and the lifting platform 20 may be moved so that the movement ratios of the adjustment vehicle C in the X-axis and Y-axis directions are kept constant and do not change. Other configurations and operations are similar to those of the first embodiment.

The above-described first to fourth embodiments are merely for showing preferable embodiments of the present invention, and the present invention is not limited to these, and various design changes can be made. For example, as concrete structures of the respective constituent devices such as the grinding wheel G, the adjusting wheel C, and the receiving plate B, conventionally well-known structures other than the illustrated example can be adopted according to the purpose and application.

[0044]

As described in detail above, according to the present invention,
It is possible to provide at low cost a grinding technique having a simple structure, which has the following excellent effects and can improve the production efficiency while ensuring a high roundness of the work.

That is, an angle formed by a straight line connecting the axis of the adjusting wheel and the axis of the work and a horizontal line passing through the axis of the work is geometrically approximately equal to the height angle of the heart (angle corresponding to the height of the heart).
Since the adjustment wheel or grinding wheel is cut so as to approach the work direction in the state set so that it is possible to maintain the substantial center-of-height angle at the optimum value at all times, The highest roundness is ensured and high-precision products are stably supplied.

Further, since the shaft center of the work is supported so as to be substantially at the same height as the shaft center of the grinding wheel, and the center height is set to almost zero, the outer diameter dimensions of the grinding wheel and the adjusting wheel change with time. Even if the initial positions of these shaft centers come closer to the work side due to wear due to mechanical abrasion, the optimum value of the above-mentioned center-height corresponding angle, that is, the substantial center-height angle does not change. As a result, it is not necessary to adjust the center height corresponding to the reduction in the outer diameter of the grinding wheel / adjustment wheel as in the conventional case, and the work axis is always maintained at a constant height.

Therefore, it is not necessary to adjust the height of the receiving plate for adjusting the core height and the height of the work loading device and the work unloading device associated with this adjustment, and automation of the grinding work and labor saving can be realized. As a result, in combination with the above effect, it becomes possible to supply a highly accurate product more efficiently and stably, which is advantageous in energy saving measures.

[Brief description of drawings]

FIG. 1 is a schematic front view showing a centerless grinding machine that is Embodiment 1 of the present invention.

FIG. 2 is a front view showing a work supporting structure of a concentric grinder.

FIG. 3 is a schematic front view showing a centerless grinding machine that is Embodiment 2 of the present invention.

FIG. 4 is a front view showing a work support structure of a concentric grinder.

FIG. 5 is a schematic front view showing a centerless grinding machine that is Embodiment 3 of the present invention.

FIG. 6 is a front view showing a work support structure of a concentric grinder.

FIG. 7 is a front view showing a work supporting structure of a centerless grinding machine that is Embodiment 4 of the present invention.

FIG. 8 is a schematic front view showing a conventional centerless grinding machine.

FIG. 9 is a front view showing the work supporting structure of the concentric grinder.

[Explanation of sign]

W Work G Grinding wheel C Adjusting wheel B Support plate Ba Support surface of receiving plate O Work axis O _G Axis of grinding wheel O _c Adjuster axis h Center height γ Center height angle Γ Center height corresponding angle 1 Equipment bed 2 Grindstone chassis 3 Slide base 4 Feed screw device for slide base 5 Adjusting chassis 6 Support plate stand 20 Lifting table 21 Feed screw device for lifting table

Claims (6)

[Claims] 1. A centerless grinding method in which a workpiece is supported between a grinding wheel, an adjusting wheel and a receiving plate, and a cylindrical surface or an end surface of the grinding wheel is ground, and the axis of the workpiece is substantially the same height as the axis of the grinding wheel. The work is supported on the backing plate so that the angle between the straight line connecting the axis of the adjusting wheel and the axis of the workpiece and the horizontal line passing through the axis of the workpiece is geometric. The adjusting wheel is placed so that the angle corresponding to the height of the center is approximately equal to the angle of height, and the adjusting wheel or grinding wheel is cut so that its axis approaches the axis of the workpiece. A centerless grinding method characterized in that a cylindrical surface or an end surface of an object is ground. 2. A centerless grinding apparatus in which a workpiece is supported between a grinding wheel, an adjusting wheel and a receiving plate, and its cylindrical surface or end face is ground, wherein the receiving plate is supported on the supporting surface. Is set and arranged so that the shaft center of the wheel is almost at the same height as the shaft center of the grinding wheel, and the adjusting wheel has a straight line connecting the shaft center and the shaft center of the workpiece and a horizontal line passing through the shaft center of the workpiece. The angle is set so that it is geometrically equivalent to the height corresponding to the height, and the axes of the adjusting wheel and the grinding wheel can move linearly relative to the axis of the workpiece. A centerless grinding device characterized in that it is provided in. 3. The centerless grinding apparatus according to claim 2, further comprising an adjusting wheel support structure capable of adjusting the angle corresponding to the center height. 4. An adjustment chassis is provided on the apparatus bed so as to be linearly movable along the reference value of the angle corresponding to the center of height, and the adjustment car is provided on the adjustment chassis with respect to the moving direction of the adjustment chassis. And is supported so as to be vertically movable and adjustable.
The centerless grinding device described in 1. 5. An adjustment chassis is provided on a device bed so as to be movable in the horizontal direction, and the adjustment car is provided on the adjustment chassis so as to be movable in the vertical direction. The centerless grinding apparatus according to claim 2, wherein the relative movement amount is controlled to a predetermined movement ratio, and the adjusting wheel is linearly movable at the center height corresponding angle. 6. The centerless grinding apparatus according to claim 3, comprising the configuration of claim 5, wherein the center height corresponding angle can be adjusted by adjusting the movement ratio.