JP2000233349A - Flattening apparatus for machine part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce grinding force and restrain warp of a workpiece by forming a number of recessed grooves in the end face of a grinding wheel coming into contact with a workpiece, and setting the rotating speeds of two grinding wheels to a designated value or more. SOLUTION: A flattening apparatus has two grinding wheels (first and second grinding wheels) 2, 3 clamping a flat part of a ring-shaped workpiece 1, and a number of recessed grooves 4 are concentrically formed in the contact surface sides of the first and second grinding wheels 2, 3 with the workpice 1. While the workpiece 1 is rotated in the direction of an arrow E at a designated speed through a rotary support mechanism, the peripheral speeds of the first and second grinding wheels 2, 3 are set to a designated speed or more, and the first and the second grinding wheels 2, 3 are rotated at a high speed in the direction of an arrow F, thereby double-end flattening the workpiece 1 to restrain generation of residual warp remaining after flattening. Accordingly, grinding with good flat accuracy can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plane machining apparatus for machine parts, and more particularly to a plane machining apparatus for machine parts for grinding a plane of a ring-shaped workpiece such as an annular member.

[0002]

2. Description of the Related Art Conventionally, when grinding a plane portion of a ring-shaped workpiece such as an annular member, as shown in FIGS. 18 and 19, two grindstones (first and second) formed in a circular shape are used. The workpiece 102 is guided between the second grindstones 101a and 101b), and the workpiece 102 is supported and rotated by a rotation mechanism (not shown), while rotating the grindstones 101a and 101b in the direction of arrow a. The workpiece 10 is moved by the two grindstones 101a and 101b by infeed feeding in the direction b.
2 is pressed in the axial direction, whereby both planes of the workpiece 102 are simultaneously ground (double-sided plane grinding) (hereinafter, referred to as “first conventional technique”).

As another prior art, as shown in FIGS. 20 and 21, only two grinding wheels (a first grinding wheel 10 and a second grinding wheel 10) are provided in a plane area corresponding to a central angle α of a workpiece 102.
4a, 104b), the workpiece 102 is guided between three rolls 105a to 105c.
While rotating the workpiece 102 in the direction of arrow c while supporting the workpieces, the workpieces are rotated by the two infeed wheels in the same manner as described above while rotating the grindstones 104a and 104b in the direction of arrow d. The two planes of the workpiece 102 are simultaneously ground by clamping the workpiece 102 in the axial direction (partial double-sided surface grinding) (hereinafter, referred to as “second conventional technique”).

[0004]

However, in the above-mentioned first prior art, the width T is smaller than the outer diameter D, and the rigidity in the axial direction is small, like a rolling wheel of a rolling bearing. In the case of grinding the plane portion of the workpiece 102, there is a problem that even if sparking is performed for a long time, residual warpage occurs at the completion of the processing because the grinding force acts on the entire surface of the workpiece 102.

That is, as shown in FIG. 22A, a workpiece 102 having a warpage δ is moved to the first and second grindstones 1.
01a and 101b, the first and second grinding wheels 101 are fed by infeed in the direction of arrow b.
a and 101b come into contact with the workpiece 102,
As shown in (b), when the grinding force for pressing the workpiece 102 in the directions of the arrows e and h becomes equal to or greater than the threshold, the grinding by the first and second grindstones 101a and 101b is started.

However, in this case, even if the grinding proceeds and a predetermined grinding process is completed, as shown by a phantom line in FIG. 22 (c), spark-out occurs with the residual warpage amount δ ₀ due to elastic deformation. Is completed, and the grinding process is completed. Therefore, the workpiece 102 is moved to the first and second grinding wheels 101.
a and 101b, there is a problem that a residual warpage amount δ ₀ due to the elastic deformation occurs, and it is not possible to obtain a mechanical part having a desired plane accuracy.

[0007] That is, in FIG.
When n acts on the entire surface of the workpiece 102, the residual warpage amount δ
_{Although 0} should theoretically not be generated as “0”, the actual relationship between the grinding time and the grinding amount and the elastic modulus of the mechanical system and the workpiece are extremely smaller than the threshold value Fth. Therefore, the residual warpage δ ₀ does not become “0”, and in today's rolling wheels for ultra-precision bearings and the like, which require a high level of plane machining accuracy,
It has become necessary to further reduce the residual warpage amount δ ₀ .

[0008] In the second prior art, the workpiece 102
Only the plane area corresponding to the central angle α is guided and ground between the first and second grindstones 104a and 104b. Therefore, unlike the first prior art, the grinding force acts only on the plane area. Apparently, the rigidity of the workpiece 102 in the axial direction increases. Therefore, it is possible to suppress the occurrence of the residual warpage amount δ _{0 with} respect to the workpiece 102, and it is considered that the planar accuracy can be improved as compared with the first related art. Further, since the grinding is performed with a part of the workpiece 102 being put out of the grindstone, it is considered that the mechanism for supporting and rotating the workpiece 102 can be performed with a relatively easy configuration.

However, in the second prior art, the rotation axes of the first to third rolls 105a to 105c are mounted parallel to the rotation axis of the workpiece 102, but in practice, the allowance error is The first and third rolls 105a to 105c are rotationally driven because the rotation shafts are not completely parallel to each other because they are mounted obliquely. ~ 3rd
A so-called skew force is generated between the rolls 105a to 105c and a force acts in the axial direction of the workpiece 102. In this case, the inclination of the shaft determines the direction of the force, and the magnitude is constant regardless of the amount of inclination. That is, the first to third rollers 1
Since the workpieces 0a to 10c rotate while slidingly contacting the workpiece 102, a frictional force is generated in the axial direction of the workpiece 1 and the rotation axes of the first to third rolls 105a to 105c are processed. Since the skew force is applied to the workpiece 102 in the axial direction because the skew force is applied to the workpiece 102, the force acts as a moment force on the workpiece 1. There is a problem that it adversely affects the planar processing accuracy.

As a measure for solving such a problem, it is conceivable to increase a plane area of the workpiece 102 guided between the first and second grindstones 104a and 104b. In this case, the plane area of the workpiece 102 on which the grinding force Fn acts increases, and a similar problem as the first related art newly arises.
That is, when the plane area increases, the area where the grinding force Fn acts increases. As a result, in the case of a mechanical component having a small rigidity such as an annular member, a residual warpage amount δ ₀ occurs and the planar accuracy of the mechanical component is reduced. A new point occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a plane machining apparatus for machine parts capable of obtaining machine parts such as annular members having desired plane accuracy. .

[0012]

SUMMARY OF THE INVENTION When a ring-shaped workpiece is sandwiched between two oppositely disposed grinding wheels, and the workpiece is subjected to double-sided surface grinding, the feed of the grinding wheel is performed. The relationship between the quantity x, the width dimension T of the workpiece, and the time t is generally as shown in FIG. In the drawing, the solid line indicates the relationship between the feed amount x of the grinding wheel and the time t, and the chain line indicates the relationship between the width T of the workpiece and the time t.

That is, when the grindstone approaches the workpiece at a predetermined grindstone feed speed, the grindstone contacts the workpiece at time t1 and starts grinding. Then, when the feed amount x of the grindstone increases, the grinding of the workpiece proceeds, so that the width dimension T of the workpiece decreases in proportion to the feed amount of the grindstone. Then, when the predetermined time t2 is reached, the feed of the grindstone is stopped to start spark-out, and thereafter, the width dimension T of the workpiece is set to the predetermined dimension T.
It approaches 1

If the deviation between the feed amount x of the grinding wheel and the width T of the workpiece is Δx, the grinding force per unit wheel width (hereinafter, referred to as a unit grinding force) fn is expressed by the following equation (1). You.

Fn = k · Δx (1) where k is the elastic modulus of the mechanical system and the workpiece.

On the other hand, as shown in FIG. 2, the grinding efficiency per unit wheel width (hereinafter, referred to as unit grinding efficiency Zw) is proportional to the unit grinding force fn.

That is, the unit grinding force fn reaches the threshold value fth at time t1 after the surface processing apparatus is driven and starts grinding, and thereafter the unit grinding force fn is increased in the direction of the arrow A in proportion to the increase in the unit grinding efficiency Zw. To increase. Next, at time t2 when the unit grinding force fn becomes the predetermined value f1, the feed of the grindstone is stopped and spark out is started. And the unit grinding force f
n decreases in the direction of arrow B in proportion to the decrease in the unit grinding efficiency Zw, and the unit grinding force fn returns close to the threshold value fth at the start of grinding. In other words, the unit grinding force fn starts the grinding at the threshold value fth, starts the spark-out after the grinding by the in-feed feed ends, and ends the spark-out when the unit grinding force fn returns close to the threshold value fth. Then, the grinding process is completed.

Therefore, assuming that the deviation between the feed amount x of the grindstone at the time t1 and the width T of the workpiece, that is, the initial deviation is Δx ₀ , the threshold value fth is expressed by equation (2).

[0019] _{fth = k · Δx 0 ... (} 2) residual warpage [delta] ₀ From these is represented by the initial deviation [Delta] x _0, in order to suppress the residual warp amount [delta] ₀ is the initial deviation Δ
It is necessary to decrease x ₀ , that is, the threshold value fth. In other words, believed to suppress the residual warp amount [delta] _0, it is necessary to start the grinding with a small unit grinding power.

As a result of intensive studies by the present inventors, it has been found that by increasing the peripheral speed of the grinding wheel, grinding can be started with a small unit grinding force.

Further, the width of the grinding wheel is W, and the grinding force of the entire width of the grinding wheel (hereinafter, this grinding force is referred to as "total grinding force") is Fn.
In this case, the total grinding force Fn is represented by Expression (3).

Fn = W · fn (3) Accordingly, the threshold value Fth can be reduced by reducing the grindstone width W. However, there is a limit in reducing the width W of the grinding wheel in consideration of the so-called grinding burn and the falling off of the grinding wheel.

Therefore, in the present invention, by providing a large number of grooves on the surface of at least one of the two grindstones, an effect equivalent to reducing the grindstone width W is provided.

That is, the apparatus for flattening mechanical parts according to the present invention guides a workpiece between two grindstones arranged opposite to each other, and rotates the two grindstones and the workpiece. In a plane machining apparatus for mechanical parts, which grinds a plane of the workpiece by squeezing the workpiece with the two grindstones, the machining of at least one grindstone of the two grindstones is performed. Many concave grooves are formed on the end face in contact with the object,
In addition, the rotation speed of the two whetstones is set to a predetermined value or more.

On the other hand, considering the simplicity of the configuration of the rotary drive mechanism for the workpiece, like the second prior art described above,
It is desirable that only a plane area (predetermined area) corresponding to the center angle α of the grindstone is guided between the grindstones, and a region other than the predetermined area is arranged outside the grindstone for grinding.

However, if the predetermined region inserted between the grinding wheels is too small or too large, the workpiece cannot be ground uniformly, and the plane accuracy cannot be improved. Therefore, it is preferable to perform a so-called partial double-sided surface grinding by guiding only the plane region corresponding to the predetermined range in which the center angle α of the workpiece is in the vicinity of 180 ° between the two grinding wheels.

Therefore, the present invention provides the above-mentioned planar processing apparatus, wherein the central angle α of the workpiece is within a predetermined range (preferably α = 180 ° ± Δα (Δα
Is characterized in that a plane area corresponding to an allowable predetermined angle) is guided between the two grinding wheels and ground.

In this case, the rotating mechanism for supporting and rotating the workpiece is generally composed of three supporting and rotating parts, but the influence of the moment force on the surface of the workpiece is avoided. To do so, of the three support / rotation units,
And a driven rotating part, and a driven rotating part.
A rotatable member supporting portion that supports the respective rotating members of the driving rotating portion and the driven rotating portion is rotatable, and a rotation axis of the rotating member supporting portion has a predetermined shift amount with respect to a rotation axis of the rotating member. It is preferable that the support / rotation unit is configured.

Further, instead of making the rotator support portion rotatable, the rotator support portion may be made of an elastic body such as a leaf spring.

Further, the rotation mechanism may be constituted by two rotation drive units and one fixed member.

[0031]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 3 is a plan view of a principal part showing a first embodiment of a flat machining apparatus for machine parts according to the present invention, and FIG. 4 is a sectional view taken along the line CC of FIG.

That is, the planar processing apparatus has two grindstones (first and second grindstones 2 and 3) for pressing the planar portion of the ring-shaped workpiece 1, and includes the first and second grindstones. On the contact surface side of the grinding stones 2 and 3 with the workpiece 1 (hereinafter, this contact surface side is referred to as “contact end surface”), a number of concave grooves 4 are formed concentrically.

In this plane machining apparatus, the workpiece 1 is rotated in the direction of arrow E at a predetermined speed via a rotation support mechanism (not shown), while the peripheral speed of the first and second grindstones 2 and 3 is reduced. The first and second grindstones 2 and 3 are rotated at a high speed in a direction indicated by an arrow F at a predetermined speed (for example, 100 m / sec) or more, whereby the workpiece 1 is subjected to double-sided surface grinding. The generation of the residual warpage amount δ ₀ that can remain later is minimized.

Hereinafter, the reason why the peripheral speed is set to be equal to or higher than the predetermined speed as described above, and that a large number of grooves 4 are provided on the contact end surfaces of the first and second grinding wheels 2 and 3 will be described in detail.

(1) The reason why the peripheral speed is set to be equal to or higher than the predetermined speed If the deviation between the feed amount x of the grindstones 2 and 3 and the width dimension T of the workpiece is Δx, the unit grinding force fn is calculated by the equation It is represented by (1).

Fn = k · Δx (1) where k is the elastic modulus of the mechanical system and the workpiece.

Further, the relationship between the threshold value fth for starting the grinding and the initial deviation Δx ₀ is also expressed by the equation (2) as described above.

Fth = k · Δx ₀ (2) Since the unit grinding force fn returns to the threshold value fth when the spark out is completed, the residual warpage δ ₀ is not the initial deviation Δx ₀ itself, but Is considered to have a correlation.

That is, the smaller the initial deviation Δx _{0, the} earlier the start of the grinding process, and therefore the smaller the warpage amount δ of the workpiece 1 before the grinding process, and as a result, the residual warpage amount δ after the spark-out is completed. ₀ also becomes smaller. And
Since the elastic coefficient k is a constant uniquely determined by the mechanical system, the material of the workpiece 1, etc., it is considered that the threshold fth should be reduced as much as possible according to the equation (2) in order to reduce the initial deviation Δx _0. Can be

FIG. 5 is a characteristic diagram showing the relationship between the unit grinding efficiency Zw and the unit grinding force fn using the peripheral speed V of the grinding wheel as a parameter. The unit grinding force fn when the unit grinding efficiency Zw is "0" is a threshold value. fth. In the figure, □ is peripheral speed 100
m / sec, ● indicates a peripheral speed of 130 m / sec, ○ indicates a peripheral speed of 150
m / sec, ▲: peripheral speed 175 m / sec, △: peripheral speed 204
The case of m / sec is shown.

As is apparent from FIG. 5, the threshold value fth decreases as the peripheral speed V increases.

Therefore, by setting the peripheral speed V of the grindstones 2 and 3 to a predetermined speed or more, for example, a high-speed rotation region of 100 m / sec or more, the threshold value fth becomes small,
Therefore, the initial deviation Δx ₀ can be set to a small value equal to or smaller than a predetermined value, whereby the occurrence of the residual warpage amount δ ₀ can be suppressed and the planar accuracy of the workpiece 1 can be improved.

For the above reasons, in this embodiment, the peripheral speed of the grindstones 2 and 3 is set to a predetermined speed (for example, 100 m / sec).
Set as above.

(2) The reason why a large number of concave grooves 4 are formed on the contact end surfaces of the first and second grinding wheels 2, 3 As described above, by increasing the peripheral speed V of the grinding wheels 2, 3, the unit grinding force fn is increased. However, in order to suppress the occurrence of the residual warpage amount δ ₀ , it is necessary to further reduce the overall threshold value Fth in consideration of the grinding wheel width W of the grinding wheels 2 and 3.

That is, the total grinding force Fn of the grindstone is represented by the product of the grindstone width W and the unit grinding force fn, as shown in Expression (3).

Fn = W · fn (3) On the other hand, as is apparent from FIG. 5, the unit grinding efficiency Zw
Is represented by Expression (4).

Zw = λ · (fn−fth) (4) That is, from the equation (4), the unit grinding efficiency Zw is “0”.
In this case, the unit grinding force fn becomes equal to the threshold value fth. Therefore, the overall threshold value Fth at the time of the threshold value fth is expressed by the following equation (5).

Fth = W · fth (5) Accordingly, in order to reduce the overall reference value Fth, the grinding wheel width W
Need to be narrower. However, there is a limit in reducing the grindstone width W due to the necessity of processing various types of mechanical parts.

Therefore, a large number of grooves 4 are provided in the grindstones 1 and 2 to secure the contact between the workpiece 1 and the grindstones 2 and 3.
The same operation and effect as when the grinding wheel width W is reduced are provided.

As described above, in the first embodiment, the first
And the peripheral speed V of the second grindstones 2 and 3 is set to a predetermined speed or higher to rotate at high speed, and since a large number of concave grooves 4 are formed in the contact end surfaces of the grindstones 2 and 3, the residual warpage amount δ ₀
Generation can be suppressed as much as possible, and grinding with good plane accuracy can be performed.

FIG. 6 is a plan view of a main part of a second embodiment of the flattening apparatus according to the present invention, and FIG.
It is sectional drawing.

That is, in the second embodiment, a plane area corresponding to a predetermined range where the central angle α of the workpiece 1 is near 180 ° is guided between the first and second grinding wheels 5 and 6. , As in the first embodiment, the first and second grindstones 5,
While the peripheral speed V of the workpiece 6 is being rotated at a high speed at a predetermined speed (100 m / sec) or more, partial double-sided surface grinding of the workpiece 1 is performed.

The first grindstone 5 is formed of an elastic grindstone having a large number of grooves 7 formed on the contact end face, and the second grindstone 6 is formed of a contact endface similar to the first embodiment. Is formed of a normal grinding wheel having a large number of concave grooves 8 formed therein.

Hereinafter, the reason why the plane area in which the central angle α of the workpiece 1 corresponds to a predetermined range in the vicinity of 180 ° is guided between the first and second grindstones 5 and 6, The reason for using an elastic grindstone will be described.

(1) The plane area in which the center angle α of the workpiece corresponds to a predetermined range near 180 ° is defined by the first and second grinding wheels 5,
Reason for guiding between workpieces 6 A part of workpiece 1 is guided between grinding wheels, and the other part is taken out of the grinding wheel, compared to double-sided surface grinding, in which the entire surface of workpiece 1 is ground while being pressed between both grinding wheels. Partial double-sided surface grinding that performs surface grinding has the advantage that it is easy to rotate and support the workpiece,
It is considered that the capability of correcting the residual warpage amount δ _{0 on} the plane is reduced due to the partial double-head grinding.

[0057] In FIG. 8, the angle between the predetermined point and the origin 0 on the circumference theta, the phase [psi, when the amplitude and A _n, the deviation [Delta] Z _n from flatness, represented by formula (6) You.

[0058]

(Equation 1)

Here, A ₀ is the workpiece 1 at the origin 0
Shows the amount of deviation from the average value of the warp in the circumferential direction.

In the above equation (6), n = 1 indicates a tilt component Z ₁ at both ends P and Q of the plane of the workpiece 1, and the workpiece 1 is rotated by 180 ° as shown in FIG. flat ends P, the portion corresponding to the Q during the appears addressed to each one as the maximum value and the minimum value of the slope component Z _1. Then, such inclination component Z ₁ is readily removed by grinding by the first and second grinding 5,6.

On the other hand, when n = 2, as shown in FIG. 9 (b), the maximum value and the minimum value correspond to the ends P and Q of the plane one time each while the workpiece 1 rotates 90 °. Therefore, it is considered that the warpage amount component is approximately represented. That is, the warpage amount component ΔZ ₂ is approximated by Expression (7).

ΔZ ₂ = A ₂ · sin (2θ + ψ ₂ ) (7) By the way, in FIG. 6, the posture of the workpiece 1 is the first position.
And the central angle α of the workpiece 1 guided by the second grindstones 5 and 6. That is, when no external force acts on the workpiece 1, the posture in the y-axis direction is regulated by the points R1 and R2, and the posture in the x-axis direction is the point R3 (the grinding wheels 5 and 6 connecting the points R1 and R2). In this state, the workpiece 1 is ground by infeed while rotating the grindstone in this state.

FIG. 10 shows that the central angle α of the workpiece 1 is 120 °.
11 shows a case where the workpiece 1 is ground by the first and second grindstones 5 and 6, and FIG.
The case where the workpiece 1 is set to 80 ° and the workpiece 1 is ground by the first and second grindstones 5 and 6 is shown. FIG.
FIGS. 2 (a) to 12 (f) are diagrams schematically showing a state of grinding while the workpiece 1 makes one rotation when the central angle α is set to 120 °, and FIG. a) to FIG.
(F) is a view schematically showing a state of grinding while the workpiece 1 makes one rotation when the central angle α is set to 180 °. Then, points R1, R2 and R4 for determining the attitude of the workpiece 1 as the workpiece 1 rotates.
Moves and is ground as shown by the hatched portions in FIGS. 12 and 13.

As is apparent from FIGS. 12 and 13, when the central angle α is 180 °, the central angle α is 120 °.
Large area of the shaded portion in comparison with the case, and thus it can be seen that the amplitude A ₂ is reduced early. From this point of view, in the second embodiment, a plane area corresponding to a predetermined range in which the central angle α of the workpiece 1 is near 180 ° is guided between the first and second grinding wheels 5 and 6. It was decided to.

(2) Reason why the first grindstone 5 is constituted by an elastic grindstone As described above, when the workpiece 1 is guided between the grindstones 5 and 6 by the central angle α (≒ 180 °), the grinding is performed. In order to perform a desired warp correction on the workpiece 1, it is important to uniformly apply a grinding force in the plane of the points R1 to R4 of the grindstones 5 and 6.

Therefore, in the second embodiment, the first grindstone 5 is formed of an elastic grindstone so as to escape the so-called contact with the workpiece 1, and the grinding force is uniformly applied to the second grindstone 6 side. In this case, the warpage amount δ is reduced to correct the flatness accuracy of the first grindstone 5 side in accordance with the flatness accuracy of the second grindstone 6 at the time of spark-out. In the second embodiment, since the first and second grindstones 5 and 6 need to have the same grindstone area to balance them, the elastic grindstone (first grindstone 5) also has a large number of grooves. 7 ... provided.

FIG. 14 shows a state in which a rotation and support mechanism for rotating and supporting the workpiece 1 is attached in the second embodiment.

That is, the present rotation / support mechanism comprises one drive rotation unit 30a and two driven rotation units (first and second driven rotation units 30b and 30c).
a and the first driven rotation unit 30b are located outside the first and second grinding wheels 5 and 6, and the second driven rotation unit 30c is
And at substantially equal intervals on the outer periphery of the workpiece 1 so as to be located between the second grindstones 5 and 6.

The rotation drive unit 30a is, specifically, an arrow H
A driving roller (rotating body) 10a that slides on the workpiece 1 while rotating in the direction, a driving roller supporting section (rotating body supporting section) 11a that supports the driving roller 10a, the driving roller supporting section 11a, and the driving unit. A drive roller joint 12a for connecting the roller 10a; a drive motor 13a for rotating the drive roller 10a;
3a and a flexible coupling 14a for connecting the first drive roller 10a.

The drive roller support portion 11a includes a housing portion 15a, a plurality of rolling elements 16a, and a drive roller support body 17a.
7a are rotatable via the rolling elements 16a, and the center thereof has an offset amount ΔT in the rotation direction of the workpiece 1 with respect to the rotation axis of the driving roller 10a. It is provided shifted.

Further, the first and second driven rotating parts 30b,
30c have the same configuration.

The first and second driven rotating parts 30b, 30c
Specifically, a first or second driven roller 10b, 10c that is in sliding contact with the workpiece 1, and a first or second driven roller that supports the first or second driven roller 10b, 10c A first or second driven roller joint 12b for connecting the supporting portions 11b, 11c and the first or second driven roller supporting portions 11b, 11c and the first or second driven roller 10b, 11b; 12c, and the first and second driven rotation units 30b and 30c rotate in the arrow I direction or the arrow J direction following the rotation of the workpiece 1 rotating via the drive rotation unit 30a. .

Further, the first and second driven roller supporting portions 11b and 11c are provided with housing portions 15b and 15c.
, A plurality of rolling elements 16b,..., 16c, and driven roller support bodies 17b, 17c.

The first and second driven roller supporting bodies 17b and 17c are rotatable via rolling elements 16b and 16c, and the driven roller supporting bodies 17b and 17c are rotatable.
b and 17c have first and second driven rollers 10b and 10c such that their centers have an offset amount ΔT on the opposite side to the offset direction of the rotation drive unit 30a, that is, on the opposite side to the rotation direction of the workpiece 1. Is deviated from

As described above, the supporting / rotating mechanism is constituted by one rotation driving unit 30a and two rotation driven units 30b and 30c, and the driving roller supporting body 17a and the driven roller supporting bodies 17b and 17c are rotated. And the driving roller supporting body 17a and the driven roller supporting body 17b,
The center axis of the driving roller 10a and the driven roller 10
The reason for shifting the rotation axes b and 10c by the offset amount ΔT and setting the offset direction to the opposite direction between the driving roller 10a and the driven rollers 10b and 10c is as follows.

When the workpiece 1 is driven to rotate while supporting the outer peripheral surface of the workpiece 1 with rollers, three rollers are generally used. [Problems to be Solved by the Invention]
Since the rollers 10a to 10c rotate while sliding on the workpiece 1, frictional force is generated in the axial direction of the workpiece 1, and the rollers 10a to 10c and the rollers 1a to 10c are rotated.
The direction in which the force acts is determined by the state of contact with the roller, and the magnitude of the force is determined by the pressing force of the roller against the workpiece and the coefficient of friction. As described above, in the case of the three-roller type supporting / rotating mechanism, it is considered that a frictional force always occurs to the workpiece. And the driving roller 10a
Since acts as a moment force on the workpiece 1, it is necessary to avoid the generation of such moment force as much as possible.

Therefore, in the present supporting / rotating mechanism, one rotation driving section 30a and two rotation driven sections 30b and 30c are provided to enable each of the roller supporting bodies 17a to 17c to rotate, 10a and driven rollers 10b, 10
The rotation of the first and second driven roller support bodies 17b, 17c is delayed with respect to the rotation of the drive roller support body 17a by setting the directions of deviation of the offset amount ΔT with respect to c to be opposite to each other. Rollers and driven rollers 10a-1
The pressing force and frictional force of the workpiece 1 at 0 c are reduced, and the in-plane moment force of the workpiece 1 is suppressed.

FIG. 15 is a plan view of a principal part showing a first modification of the supporting / rotating mechanism. The first modification also has one driving rotating part 31a and two driven rotating parts 31b and 31c. The workpiece 1 is rotationally driven while supporting the outer periphery of the workpiece 1.

That is, the drive rotation unit 31a is connected to the drive roller 10a and the drive motor 13a via the flexible coupling 14a to drive the drive roller 10a to rotate, and to drive the first and second driven rotation units 31a.
b and 31c rotate following the rotation of the workpiece 1 rotating via the drive roller 10a, and support the outer periphery of the workpiece 1.

FIG. 16 is a side view showing the details of the second driven rotating portion 31c, as viewed from the arrow K in FIG.

The first driven rotating portion 31b has the same configuration as the second driven rotating portion 31c, and the driving rotating portion 31a has the same configuration as that of the second driven rotating portion 31c except for an offset direction described later. The configuration is as follows.

The second driven rotating portion 31c is, specifically,
Second driven roller 20c that supports the outer periphery of workpiece 1
And a pair of leaf springs 18c, 18c supporting the second driven roller 20c, and brackets 20c, 20c to which the leaf springs 18c, 18c are fixed via screws 19c, 19c.
And the plate springs 18c, 1 via screws 22c, 22c.
8c is fixed to the fixing member 21c so that the intersection C on the extension of the pair of leaf springs 18c, 18c, that is, the virtual center C has an offset amount ΔS with respect to the rotation axis of the second driven roller 20c. It is built in.

In the second modification, the driving roller 20a and the driven rollers 20b and 20c are formed by a pair of leaf springs 18a to 18a.
Since the periphery of the virtual center C of FIG. 8c can be elastically rotated, the pressing force of the drive roller 20a and the driven rollers 20b and 20c against the workpiece 1 is reduced, as in the support and rotation mechanism of FIG. It is possible to avoid a moment force that can act on the surface of the workpiece 1.

FIG. 17 is a plan view showing a main part of a second modification of the support / rotation mechanism. The second modification is the first modification in which the first and second grindstones 5 and 6 are provided with a first And the second drive roller 2
3a and 23b, and the second driven rotary unit 30 of FIG.
c is provided with a shoe (fixing member) 24 at a position corresponding to the two-stage pulley 2.
5 are fitted. The first and second drive rollers 23a and 23b and the drive motor 26 are connected via first and second belts 27 and 28, and the rotation of the first and second drive rollers 23a and 23b. The workpiece 1 is rotated by the driving.

In the second modified example, even if the first and second drive rollers 23a and 23b press the workpiece 1, the pressing force is applied to the shoe 24 side. The pressing force can be reduced.
In addition, the force acting in the axial direction of the second drive rollers 23a and 23b can be reduced, and the generation of a moment force acting in the plane of the workpiece 1 can be avoided. In addition, since one location on the outer periphery is supported by the shoe 24 as a fixing member instead of the roller, the configuration of the rotation mechanism can be simplified.

Further, in the second modification, the first and second
By forming the shoe 24 disposed inside the grindstones 5 and 6 into a flat plate shape, the flat portion can be easily ground even when the workpiece 1 is thin.

[0087]

As described above in detail, the flattening apparatus for machine parts of a machine part according to the present invention has a two-sided arrangement.
A work piece is guided between two whetstones, and the work piece is sandwiched between the two whetstones while rotating the two whetstones and the work piece to grind the plane of the work piece. In the planar machining apparatus for a mechanical part, a number of grooves are formed on an end surface of at least one of the two grinding stones that contacts the workpiece, and the rotation speed of the two grinding stones is a predetermined value. With the above setting, the grinding force can be reduced, the amount of warpage of the workpiece is suppressed, and the planar accuracy of the workpiece, which is a machine component, can be improved.

[Brief description of the drawings]

FIG. 1 is a characteristic diagram showing a relationship between a feed amount of a grindstone, a width dimension of a workpiece, and a grinding time.

FIG. 2 is a characteristic diagram showing a relationship between unit grinding power and unit grinding power.

FIG. 3 is a plan view of a main part showing one embodiment (first embodiment) of the flattening apparatus for machine parts according to the present invention.

FIG. 4 is a sectional view taken along the line CC of FIG. 3;

FIG. 5 is an experimental data diagram showing a relationship between a unit grinding ability and a unit grinding force.

FIG. 6 is a plan view of a principal part showing a second embodiment of the planar machining apparatus for machine parts according to the present invention.

FIG. 7 is a sectional view taken along line GG of FIG. 6;

FIG. 8 is a diagram for explaining planar accuracy of a workpiece.

FIG. 9 is a diagram for explaining processing components of a workpiece.

FIG. 10 is a diagram showing a state in which the workpiece is guided between the first and second grinding wheels so that the central angle α of the workpiece is 120 °.

FIG. 11 is a view showing a state in which the workpiece is guided between the first and second grinding wheels so that the central angle α of the workpiece is 180 °.

FIG. 12 is a diagram schematically showing a state in which grinding is performed in the state of FIG. 10;

FIG. 13 is a view schematically showing a state in which grinding is performed in the state of FIG. 11;

FIG. 14 is a plan view of an essential part showing an example of a rotation drive mechanism for a workpiece in the second embodiment.

FIG. 15 is a view showing a first modification of the rotation drive mechanism.

16 is a view as viewed in the direction of the arrow K in FIG.

FIG. 17 is a view showing a second modification of the rotation drive mechanism.

FIG. 18 is a plan view of a main part showing a first conventional technique.

FIG. 19 is a sectional view taken along line XX of FIG. 18;

FIG. 20 is a main part plan view showing a second conventional technique.

FIG. 21 is a sectional view taken along line YY of FIG. 20;

FIG. 22 is a diagram for explaining a problem of the first related art.

[Explanation of symbols]

 Reference Signs List 1 annular member (machine component) 2 first grindstone 3 second grindstone 4 concave groove 5 first grindstone 6 second grindstone

Claims (1)

[Claims] 1. A work piece is guided between two grindstones disposed opposite to each other, and the work piece is rotated by the two grindstones while rotating the two grindstones and the workpiece. In a planar machining apparatus for a mechanical component that grinds a plane of the workpiece by pinching, a number of grooves are formed on an end surface of at least one of the two grindstones that is in contact with the workpiece. And said 2
A flat machining apparatus for a machine part, wherein the rotation speed of the whetstones is set to a predetermined value or more.