JP2004243437A - Lapping apparatus and lapping method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce local damage of a convex shoe and to reduce local clogging of a lapping film and separation of abrasive grains in the case of using the convex shoe. <P>SOLUTION: This lapping apparatus 1 includes: a lapping film 11; a convex shoe 71 formed to a circular-arc surface having a convex section, provided with a convex tip part for pressing the abrasive grain surface of the lapping film to a work W, and held through a rocking pin 72 to freely make oscillating floating movement; and a floating unit 30 forcing the convex shoe to make floating movement according to the rotation of the work. A contact point between the convex shoe and the lapping film and a contact point between the lapping film and the work are dispersed. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a lapping apparatus and a lapping method for performing a film lapping process (hereinafter simply referred to as a lapping process) on a work surface of a work using a lapping film with abrasive grains (hereinafter sometimes simply referred to as a film).
[0002]
[Prior art]
For example, when finishing a workpiece having an arc-shaped cross-sectional outer peripheral surface such as a cam lobe portion or a journal portion of a camshaft or a journal portion or a pin portion of a crankshaft, recently, a lapping film provided with abrasive grains on one surface is used. Has been wrapped.
[0003]
In this lapping process, the work surface of the work is covered with a wrapping film, the film is pressed from the back with a shoe, and the work is processed on the abrasive surface of the film while rotating the work while pressing the film against the work. The lapping processing device includes a mechanism that presses the shoe against the work via the film, a mechanism that drives the work to rotate, and an oscillation that applies oscillation along the axial direction of the work to at least one of the work and the wrapping film. It has a mechanism (for example, see Patent Document 1).
[0004]
The shoes are classified into a convex shoe and a concave shoe according to the shape of the tip, and the shoe disclosed in Patent Document 1 is formed in a circular arc surface having a convex cross section and presses the abrasive grain surface of the wrapping film against the work. It is a convex shoe provided with a convex tip. The convex shoe is fixed to the device side so as not to perform a rotational movement (hereinafter, also referred to as a floating movement of shaking the head).
[0005]
[Patent Document 1]
JP-A-7-237116 (see FIGS. 1 and 2)
[0006]
[Problems to be solved by the invention]
Since the convex shoe cannot perform a floating motion of shaking the head, the contact point between the convex shoe and the wrapping film and the contact point between the wrapping film and the work surface of the workpiece are the same during the lapping process.
[0007]
For this reason, there is a problem that the shoe pressing force is concentrated on one point of the convex shoe, and the shoe is locally damaged. Further, there is a problem that the shoe pressing force is concentrated on one point of the wrapping film, and clogging of the wrapping film and separation of abrasive grains are promoted.
[0008]
The present invention has been made in order to solve the problems associated with the above-described conventional technology. When a convex shoe is used, local damage to the convex shoe is reduced, and local clogging and polishing of the wrapping film are performed. An object of the present invention is to provide a lapping apparatus and a lapping method capable of reducing the separation of grains.
[0009]
[Means for Solving the Problems]
The object of the present invention is achieved by the following means.
[0010]
The present invention relates to a lapping apparatus for performing a lapping process on a processing surface of a rotating work,
A wrapping film in which abrasive grains are provided on one surface of a thin base material,
A convex shoe formed on a circular arc surface having a convex cross section and having a convex tip for pressing the abrasive grain surface of the wrapping film against the work and held via a support shaft so as to be freely rotatable,
Floating means for rotating the convex shoe in accordance with the rotation of the work,
A lapping apparatus, wherein a contact point between the convex shoe and the wrapping film and a contact point between the wrapping film and the work are dispersed.
[0011]
Further, the present invention is a lapping method for performing lapping by pressing the abrasive surface of the lapping film against the rotating work,
A convex shoe provided with a convex tip portion formed on an arc surface having a convex cross section and held via a support shaft so as to be freely rotatable is rotated according to the rotation of the work, and the convex shoe is rotated. And a contact point between the wrapping film and the workpiece, and a contact point between the wrapping film and the workpiece.
[0012]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the lapping apparatus and the lapping method which concern on this invention, there exists an effect that the local damage of a convex shoe can be reduced, and the clogging of a lapping film and the peeling of abrasive grains can be reduced.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
(1st Embodiment)
FIG. 1 is a schematic configuration diagram showing a lapping device 1 according to a first embodiment of the present invention, and FIG. 2 shows a closed state of upper and lower arms 22 and 23 provided on the lapping device 1 so as to be openable and closable. FIG. 3 is a schematic sectional view showing the open state of the upper and lower arms 22 and 23, FIG. 4 is a configuration diagram conceptually showing a floating unit 30 of the lapping apparatus 1, and FIGS. () Is a diagram for explaining the operation of the convex shoe 71 capable of freely swinging the head. FIG. 6A is a perspective view showing an example of a camshaft 60 as a workpiece W to be wrapped, and FIG. 6B is a diagram provided for explaining each part of a cam lobe portion 61 of the camshaft 60. is there. For convenience of description, the axial direction of the camshaft 60 (left-right direction in FIG. 1) is defined as an X direction, and a horizontal direction orthogonal to the X direction (a direction orthogonal to the plane of FIG. 1) is defined as a Y direction. A vertical direction (vertical direction in FIG. 1) orthogonal to the X direction is defined as a Z direction.
[0015]
The lapping apparatus 1 according to the present embodiment will be briefly described with reference to FIGS. 1 to 4. The lapping film 11 is provided with abrasive grains on one surface of a non-stretchable and deformable thin base material. A convex shoe 71 held so as to allow the floating motion of pressing the abrasive grain surface against the work W and swinging the head, and a floating unit 30 (floating means for floating movement of the convex shoe 71 in accordance with the rotation of the work W). And a rotary drive unit 40 (corresponding to a rotary drive unit) that rotationally drives the work W, and an oscillator that imparts an oscillation along the axial direction of the work W to at least one of the work W and the wrapping film 11. Wrapping film on the processing surface 65 of the rotating workpiece W 1 to press the is subjected to lapping. The floating unit 30 includes a driving unit 31 connected to the convex shoe 71 and forcibly floating the convex shoe 71 (see FIG. 4).
[0016]
As the work W, as shown in FIG. 6A, a camshaft 60 can be cited, and the outer peripheral surface of the cam lobe portion 61 of the camshaft 60 becomes a processing surface 65 on which lapping is performed. As shown in FIG. 6 (B), the cam lobe portion 61 is continuous with a base portion d forming a base circle, a top portion a defining a cam lift, and both sides of the top portion a, and starts opening or closing a valve of the engine. It has a plurality of event parts b1 and b2 which start, and a plurality of ramp parts c1 and c2 which approach the event parts b1 and b2 from the base part d. The radius of curvature of the base portion d is constant, but the radius of curvature is very large because the event portions b1 and b2 are almost linear, and the radius of curvature of the top portion a is relatively small. The processing surface 65 of the cam lobe portion 61 has an arc shape of a non-circular cross section in which the radius from the rotation center to one portion is different from the radius to another portion.
[0017]
A plurality of pairs of the upper arm 22 and the lower arm 23 are arranged corresponding to the position of the cam lobe portion 61 (see FIG. 1).
[0018]
Hereinafter, the lapping apparatus 1 will be described in detail.
[0019]
Referring to FIG. 1, the rotary drive unit 40 includes a headstock 42 that rotatably supports a main shaft 41, a chuck 43 that is connected to a tip of the main shaft 41, and grips one end of a cam shaft 60, and a belt that is attached to the main shaft 41. A main shaft motor M <b> 1 is connected through the main shaft 44, and a tailstock 46 having a center 45 supporting the other end of the camshaft 60 is provided. The camshaft 60 is driven to rotate by the rotation of the main shaft motor M1 being transmitted via the belt 44 and the main shaft 41. By changing the rotation speed of the spindle motor M1, the work rotation speed Vw is set to a desired speed. A rotary encoder S1 (corresponding to a detecting unit) for detecting the rotational position of the workpiece W during machining is attached to the main shaft 41. The head stock 42 and the tail stock 46 are respectively provided on tables 47 and 48 slidable along the Y direction, and these tables 47 and 48 are arranged on a table 49 slidable along the X direction. ing. In order to set the camshaft 60 between the headstock 42 and the tailstock 46 and to move the camshaft 60 to the processing position, the tables 47, 48, and 49 are moved.
[0020]
The oscillation unit 50 has an eccentric rotator 51 abutting on the end face of the table 49 and an oscillation motor M2 for driving the eccentric rotator 51 to rotate. The oscillation unit 50 includes an elastic means 52 such as a spring for biasing the table 49 toward the eccentric rotator 51 in order to constantly contact the end face of the table 49 and the eccentric rotator 51. Is provided. By changing the rotation speed of the oscillation motor M2, the oscillation speed Vo is set to a desired speed (for example, 10 Hz). The amplitude of the oscillation is determined based on the amount of eccentricity of the eccentric rotator 51 with respect to the axis of the oscillation motor M2. The amount of eccentricity is about 1 mm, and the amplitude of the oscillation is about 2 mm. The amount of eccentricity of the eccentric rotator 51 can be adjusted by known means such as changing the number of inserted adjustment plates (not shown). A rotary encoder S2 that detects the rotational position of the eccentric rotator 51 is attached to the shaft of the eccentric rotator 51.
[0021]
Although there are various types of the wrapping film 11, in the present embodiment, the substrate is made of a material having high non-stretchability, for example, a polyester having a plate thickness of about 25 μm to 130 μm. A large number of abrasive grains (specifically, made of aluminum oxide, silicon carbide, diamond, or the like) having a particle size of about several μm to 200 μm are attached by an adhesive. The abrasive grains may be adhered to one surface of the base material over the entire surface, or a non-abrasive grain region having a predetermined width may be formed intermittently. The other surface of the base material is provided with a back coating for attaching a resistance material (not shown) made of rubber, synthetic resin, or the like, or, in some cases, a non-slip process to prevent the convex shoes 71 from slipping.
[0022]
Referring to FIGS. 2 and 3, wrapping film 11 is pulled out from supply reel 15, and is attached to a pair of first guide rollers R <b> 1 provided at the tip of upper arm 22 and to an inner position of upper arm 22. And a pair of fourth guide rollers R4 provided at the tip of the lower arm 23, and the like. It is wound on a take-up reel 16. The take-up reel 16 is connected to a motor M3. When the take-up reel 16 is rotated by operating the motor M <b> 3, the wrapping film 11 is sequentially fed from the supply reel 15. In order to detect the feeding amount of the wrapping film 11, a rotary encoder S3 for detecting the rotation amount is attached to the shaft of the take-up reel 16. A lock device (not shown) is provided near the supply reel 15 and the take-up reel 16, and a predetermined tension is applied to the entire film 11 by the operation of the lock device.
[0023]
The pair of upper arm 22 and lower arm 23 is rotatably provided via a support pin 24 such that the distal end on which the convex shoe 71 is disposed can be relatively opened and closed in the Z direction. One end of a hydraulic cylinder 25 operated by hydraulic pressure or pneumatic pressure is connected to the rear end of the upper arm 22 with a pin, and the front end of a piston rod 26 is connected to the rear end of the lower arm 23 with a pin. When the piston rod 26 is extended from the contracted state, the upper and lower arms 22 and 23 rotate around the support pin 24 in the direction in which the tip ends close, and enter the closed state shown in FIG. On the other hand, when the piston rod 26 is contracted from the extended state, the upper and lower arms 22 and 23 rotate in the direction in which the distal ends open, and enter the open state shown in FIG. The rotation of the upper and lower arms 22 and 23 is performed together with the wrapping film 11, and the convex shoe 71 abuts on the cam lobe portion 61 via the wrapping film 11 by the closing rotation, and the cam lobe portion 61 and the convex shoe 71 by the opening rotation. Release contact with.
[0024]
The convex shoe 71 has a convex tip portion formed on an arc surface having a convex cross section and pressing the abrasive surface of the wrapping film 11 against the work W. In the illustrated embodiment, the convex shoe 71 is configured to be able to freely move in a floating manner, and to be able to change the contact point that comes into contact with the processing surface 65 of the cam lobe portion 61 via the wrapping film 11. In this specification, the fact that the convex shoe 71 indirectly contacts the outer peripheral surface of the work W via the film 11 is abbreviated as “contact”.
[0025]
The convex shoe 71 is held by a shoe case 73 via a swing pin (corresponding to a support shaft) 72 so that the floating movement of swinging the head is free. The shoe case 73 is housed in the recess 27 formed at the tip of the upper and lower arms 22 and 23 so as to be able to move forward and backward with respect to the work W. The shoe case 73 moves while its outer surface is guided by the inner surface of the recess 27. A work clamp spring 74 composed of a compression coil spring is disposed on the back of the shoe case 73. The convex shoes 71 are pressed against the processing surface 65 via the wrapping film 11 by the elastic force of the work clamping spring 74 being urged. The upper and lower swing pins 72 are located on a line passing through the axis O of the camshaft 60 so that the shoe pressing force acts on the film 11 efficiently.
[0026]
As shown in FIG. 4, the floating unit 30 has a link mechanism 33 indicated by a two-dot chain line, one end of which is pin-connected to the convex shoe 71 and the other end of which is pin-connected to the operating rod 32 which is movable forward and backward. And a motor M4 for moving the operating rod 32 forward and backward. In order to convert the rotation operation of the motor M4 into an advance / retreat operation of the operation rod 32, an operation conversion mechanism (not shown) such as a rack and pinion mechanism is disposed between the motor M4 and the operation rod 32. When the motor M4 rotates and the operating rod 32 moves forward and backward, the link mechanism 33 operates accordingly, and the convex shoe 71 is forcibly floated around the swing pin 72. In order to detect the floating position of the convex shoe 71, a sensor S4 for detecting the advance / retreat position of the operating rod 32 is provided. The sensor S4 includes a non-contact sensor such as an optical sensor, a contact sensor such as a limit switch, and the like. The drive means 31 which is connected to the convex shoe 71 and forcibly floats the convex shoe 71 is constituted by the operating rod 32, the link mechanism 33 and the motor M4 described above. When the convex shoe 71 is forcibly floated, the convex shoe 71 is constantly pressed toward the cam lobe portion 61, and the state in which the abrasive surface of the wrapping film 11 is pressed against the processing surface 65 is maintained. . In addition, the position of the convex shoe 71 shown in FIG.
[0027]
The combination of the directions in which the upper and lower convex shoes 71 move in a floating manner can be arbitrarily determined. For example, when the upper convex shoe 71 performs a floating movement in the clockwise direction around the swing pin 72 from the initial position as an example, the lower convex shoe 71 moves clockwise about the swing pin 72 from the initial position. Floating motion may be performed in the clockwise direction, or floating motion may be performed in the counterclockwise direction. However, the floating movement of the convex shoe 71 is performed according to the rotation of the work W. Specifically, the contact points between the convex shoe 71 and the wrapping film 11 and the contact points between the wrapping film 11 and the workpiece W are changed according to the rotational position of the workpiece W during processing. There are 71 floating movements.
[0028]
With reference to FIGS. 5 (A) and 5 (B), the operation of the convex shoe 71 capable of freely swinging the head while floating will be described. FIG. 5A conceptually shows a state in which the convex shoe 71 performs a maximum floating movement in the clockwise direction around the swing pin 72 from the initial position, and FIG. A state in which the shoe 71 makes a maximum floating movement in the counterclockwise direction around the swing pin 72 from the initial position is conceptually shown. In addition, the code | symbol 12 in a figure has shown the abrasive grain of the wrapping film 11. FIG.
[0029]
As shown in FIG. 5A, when the convex shoe 71 performs the maximum floating movement in the clockwise direction, the pressed convex shoe 71 and the rear surface of the wrapping film 11 are pressed against each other at the contact point A1, and the wrapping film 11 The abrasive surface and the workpiece W are in pressure contact with each other at a contact point A2. On the other hand, as shown in FIG. 5B, when the convex shoe 71 makes a maximum floating movement in the counterclockwise direction, there is no slippage between the convex shoe 71 and the wrapping film 11, so that the pressed convex shoe 71 is pressed. 71 and the back surface of the wrapping film 11 are pressed against each other at a contact point B1, and the abrasive surface of the wrapping film 11 and the work W are pressed against each other at a contact point B2.
[0030]
Therefore, the contact points between the convex shoes 71 and the wrapping film 11 are dispersed in the range of the contact points A1 to B1. Further, the contact points between the wrapping film 11 and the work W are dispersed in the range of the contact points A2 to B2. If this range is represented by an angle θ centered on the swing pin 72, θ = 2α when the respective swing angles in the clockwise direction and the counterclockwise direction from the initial position of the convex shoe 71 are α. .
[0031]
As described above, since the contact points between the convex shoes 71 and the wrapping film 11 are dispersed within a certain range during the lapping process, the shoe pressing force is not concentrated on one point of the convex shoes 71, so that the convex shoes 71 are not concentrated. The damage of is not severe locally. Furthermore, since the contact point between the wrapping film 11 and the work W is dispersed within a certain range, the shoe pressing force does not concentrate on one point of the wrapping film 11, so that the clogging of the wrapping film 11 and the abrasive grains 12 are prevented. Exfoliation is not promoted locally.
[0032]
FIG. 7 is a schematic block diagram showing a control system of the lapping apparatus 1 according to the present invention.
[0033]
Referring to FIG. 7, rotary encoders S1, S2, S3 and sensor S4 are connected to controller 100 (corresponding to control means) mainly composed of a CPU and a memory, and determine the rotational position of cam lobe section 61 during machining. , A detection signal relating to the advance / retreat position of the operating rod 32 that determines the floating position of the convex shoe 71 is input to the controller 100. A detection signal related to the rotation speed of the spindle motor M1 that determines the work rotation speed Vw and a detection signal related to the rotation speed of the oscillation motor M2 that determines the oscillation speed Vo are also input to the controller 100. The controller 100 controls the floating movement of the convex shoe 71 in accordance with the rotational position of the cam lobe section 61 detected by the rotary encoder S1.
[0034]
The change control of the floating movement of the convex shoe 71 is performed by controlling the contact point between the convex shoe 71 and the wrapping film 11 and the contact between the wrapping film 11 and the cam lobe 61 according to the rotational position of the cam lobe 61 during processing. This is done by controlling the operation of the driving means 31 of the floating unit 30 so as to change the point.
[0035]
Specifically, the controller 100 moves the operating rod 32 forward and backward in accordance with the rotational position of the cam lobe portion 61 during processing, operates the link mechanism 33 accordingly, and moves the convex shoe 71 around the swing pin 72. Then, a control signal for controlling the rotation of the motor M4 is output to the motor M4 so as to perform the floating motion. Thereby, the contact points between the convex shoes 71 and the wrapping film 11 are dispersed within a certain range (for example, the range of the contact points A1 to B1 shown in FIG. 5), and further, the wrapping film 11 and the work W Are dispersed within a certain range (for example, contact points A2 to B2 shown in FIG. 5).
[0036]
Next, the operation of the present embodiment will be described.
[0037]
First, the cam shaft 60 is supported between the head stock 42 and the tail stock 46, and the upper and lower arms 22 and 23 are moved to the position of the cam lobe 61. At this time, the fluid pressure cylinder 25 has contracted the piston rod 26, and holds the upper arm 22 and the lower arm 23 in the open position. Thereafter, the fluid pressure cylinder 25 is operated to extend the piston rod 26, and the upper and lower arms 22, 23 are rotated in the closing direction. By this closing rotation, the wrapping film 11 is set on the processing surface 65 of the cam lobe portion 61.
[0038]
While the upper and lower arms 22, 23 are being opened and rotated, the motor M3 is operated to rotate the take-up reel 16. The lapping film 11 moves by a predetermined amount, and a new abrasive grain surface is set on the processing surface 65. Thereafter, when the lock device provided near the supply reel 15 is locked and the take-up reel 16 is rotated, a predetermined tension is applied to the wrapping film 11. Next, when the lock device near the take-up reel 16 is locked, the wrapping film 11 is provided with tension and without slack.
[0039]
When the camshaft 60 is clamped, the resilient force of the work clamping spring 74 is applied to the convex shoe 71 to be pressed toward the cam lobe portion 61, and the abrasive surface of the wrapping film 11 is pressed against the processing surface 65.
[0040]
Then, when the rotation unit 50 is operated to rotate the camshaft 60 around the axis while operating the oscillation unit 50 to apply the oscillation along the axial direction to the camshaft 60, the shoe holding the convex shoe 71 is obtained. While the case 73 advances and retreats in accordance with the rotation of the cam lobe portion 61 in the concave portion 27, the processing surface 65 of the cam lobe portion 61 is wrapped.
[0041]
During this processing, the rotary encoder S1 detects the rotational position of the cam lobe part 61, and the controller 100 controls the floating movement of the convex shoe 71 according to the detected rotational position of the cam lobe part 61. That is, the controller 100 controls the operation of the motor M4, moves the operating rod 32 forward and backward, activates the link mechanism 33 accordingly, and causes the convex shoe 71 to perform floating movement around the swing pin 72.
[0042]
Thereby, the contact points between the convex shoes 71 and the wrapping film 11 are dispersed within a certain range, and further, the contact points between the wrapping film 11 and the work W are dispersed within a certain range.
[0043]
During the lapping process, the camshaft 60 is rotated forward a predetermined number of times (for example, five times), and then reversely rotated the same number of times. By changing the rotation direction, the clogging of the wrapping film 11 is eliminated and the performance is maintained.
[0044]
As described above, since the contact points between the convex shoes 71 and the wrapping film 11 are dispersed within a certain range during the lapping process, the shoe pressing force is not concentrated on one point of the convex shoes 71, so that the convex shoes 71 are not concentrated. Local damage can be reduced.
[0045]
Furthermore, since the contact point between the wrapping film 11 and the work W is dispersed within a certain range, the shoe pressing force does not concentrate on one point of the wrapping film 11, so that the wrapping film 11 can be locally clogged or grinded. The separation of the grains 12 can be reduced. This means that when paying attention to the work amount of the wrapping film 11, the work surface is dispersed, so that the work amount increases. Therefore, as a result of the work amount of the wrapping film 11 being increased, it is possible to improve the finished surface roughness of the processed surface 65 and shorten the processing time.
[0046]
The camshaft 60 has a large number of cam lobes 61, and lapping is performed on these cam lobes 61 all at once. When the lapping process is completed, the hydraulic cylinder 25 is operated to contract the piston rod 26, and the upper and lower arms 22, 23 are rotated in the opening direction, so that the camshaft 60 can be taken out. After taking out the camshaft 60, if another camshaft 60 is set, the same lapping process can be started.
[0047]
As described above, according to the lapping apparatus 1 of the above-described first embodiment, the wrapping film 11 and the convex formed on the arcuate surface having a convex cross-section and pressing the abrasive grain surface of the wrapping film 11 against the workpiece W. And a floating unit 30 for rotating the convex shoe 71 in accordance with the rotation of the workpiece W. Since the contact points between the convex shoes 71 and the wrapping film 11 and the contact points between the wrapping film 11 and the work W are dispersed, when the convex shoes 71 are used, This has the effect of reducing excessive damage and reducing local clogging of the wrapping film 11 and peeling of the abrasive grains 12. In addition, by reducing local clogging of the wrapping film 11 and peeling of abrasive grains, the work amount of the wrapping film 11 is increased, thereby improving the finished surface roughness of the processing surface 65 and shortening the processing time. Can be achieved.
[0048]
The floating unit 30 includes a driving unit 31 connected to the convex shoe 71 for forcibly rotating the convex shoe 71, and a rotation driving unit 40 for driving the work W to rotate, and detecting a rotation position of the work W. The contact point between the convex shoe 71 and the wrapping film 11 and the contact point between the wrapping film 11 and the work W are changed according to the rotary encoder S1 to be rotated and the rotational position of the work W during processing. Since the controller 100 for controlling the operation of the driving means 31 is further provided, in addition to the above-described effects, the range in which the contact points are dispersed can be arbitrarily and easily set.
[0049]
Further, since the wrapping film 11 is non-stretchable and deformable, the work W can be subjected to a suitable lapping process.
[0050]
The lapping apparatus 1 according to the present embodiment is a lapping method in which the lapping process is performed by pressing the abrasive surface of the lapping film 11 against the rotating workpiece W, and the lapping process is performed in a convex shape formed on an arc surface having a convex cross section. The convex shoe 71 having the tip end and held via the swing pin 72 so as to be freely rotatable is rotated in accordance with the rotation of the work W, and the contact between the convex shoe 71 and the wrapping film 11 is made. This embodies a lapping method for dispersing points and contact points between the wrapping film 11 and the work W. As described above, when the convex shoes 71 are used, local damage to the convex shoes 71 is performed. And the effect of reducing local clogging of the wrapping film 11 and peeling of the abrasive grains 12 can be reduced. It is possible to shorten the machining time while.
[0051]
(Second embodiment)
FIG. 8 is a configuration diagram conceptually showing a floating unit 130 according to the second embodiment of the present invention, and FIGS. 9A to 9D are diagrams for explaining the operation of the floating unit 130. Note that the same reference numerals are given to members common to the first embodiment, and description thereof will be omitted. FIG. 9 shows the movement of only the upper convex shoe 71.
[0052]
The floating unit 30 of the first embodiment includes a driving unit 31 for forcibly floating the convex shoe 71, and is suitably applied to the case where the lapping process is performed by changing the rotation direction of the work W in both forward and reverse directions. Is done. On the other hand, the floating unit 130 according to the second embodiment is suitably applied to a case where the workpiece W is rotated only in one direction to perform the lapping. This will be described below.
[0053]
Similarly to the first embodiment, the lapping apparatus according to the second embodiment also includes a convex tip portion formed on a circular arc surface having a convex cross section and pressing the abrasive grain surface of the wrapping film 11 against the workpiece W. It has a convex shoe 71 held via a swing pin 72 so that a floating motion of shaking the head is free, and a floating unit 130 for floating the convex shoe 71 in accordance with the rotation of the work W.
[0054]
As shown in FIG. 8, the floating unit 130 includes a pair of spring members 75 and 76 for urging the convex shoes 71 from both sides along the direction in which the convex shoes 71 move in a floating manner. The force applied to the convex shoe 71 by the pair of spring members 75 and 76 acts to cause the convex shoe 71 to perform a floating motion in a direction opposite to the rotation direction of the work W. That is, assuming that the rotation direction of the work W is the clockwise direction indicated by the arrow r, the force applied by the pair of spring members 75 and 76 to the convex shoe 71 causes the upper convex shoe 71 to turn leftward in the drawing. To move the lower convex shoe 71 to the right in the drawing.
[0055]
In order to apply such a force to the convex shoe 71, the pair of spring members 75 and 76 have different spring constants. When the spring members 75 and 76 are formed of, for example, tension coil springs, the relationship that the spring constant of the spring member 75> the spring constant of the spring member 76 may be satisfied. May satisfy the relationship that the spring constant of the spring member 75 <the spring constant of the spring member 76.
[0056]
Also in the second embodiment, when the rotation unit 50 is operated to rotate the camshaft 60 around the axis while operating the oscillation unit 50 to apply the oscillation along the axial direction to the camshaft 60, the convexity is obtained. While the shoe case 73 holding the shoe 71 advances and retreats in the recess 27 following the rotation of the cam lobe portion 61, the processing surface 65 of the cam lobe portion 61 is lapping-processed.
[0057]
During this processing, as shown in FIGS. 9A to 9D, the work W rotates only in the clockwise direction indicated by the arrow r. Further, the force applied to the convex shoe 71 by the pair of spring members 75 and 76 acts so as to cause the convex shoe 71 to perform floating movement in a direction opposite to the rotation direction of the work W.
[0058]
With the rotation of the work W, the convex shoe 71 performs a floating movement toward the right in the drawing (FIGS. 9A to 9C). Then, when the processing portion moves from the top portion a having a relatively small radius of curvature to the substantially linear event portions b1 and b2, the convex shoe 71 floats to the left in the drawing by the action of the spring member 75. (FIG. 9D).
[0059]
Thereby, the contact points between the convex shoes 71 and the wrapping film 11 are dispersed within a certain range, and further, the contact points between the wrapping film 11 and the work W are dispersed within a certain range.
[0060]
As described above, even in the second embodiment, during the lapping process, the contact point between the convex shoe 71 and the wrapping film 11 is dispersed within a certain range, so that the shoe pressing force of the convex shoe 71 is reduced. Since it does not concentrate on one point, local damage of the convex shoe 71 can be reduced.
[0061]
Furthermore, since the contact point between the wrapping film 11 and the work W is dispersed within a certain range, the shoe pressing force does not concentrate on one point of the wrapping film 11, so that the wrapping film 11 can be locally clogged or grinded. The separation of the grains 12 can be reduced. In addition, as a result of the work amount of the wrapping film 11 being increased, it is possible to improve the finished surface roughness of the processed surface 65 and shorten the processing time.
[0062]
As described above, according to the lapping apparatus of the second embodiment, the wrapping film 11 and the convex end portion formed on the arcuate surface having a convex cross section and pressing the abrasive grain surface of the wrapping film 11 against the workpiece W. And a floating unit 130 that rotates the convex shoe 71 in accordance with the rotation of the workpiece W, the convex shoe 71 being held via a swing pin 72 so as to be freely rotatable, and Since the contact points between the wrapping film 11 and the wrapping film 11 and the contact points between the wrapping film 11 and the work W are dispersed, when the convex shoes 71 are used, local damage of the convex shoes 71 is prevented. This has the effect of reducing local clogging of the wrapping film 11 and peeling off of the abrasive grains 12. Further, by reducing the local clogging of the wrapping film 11 and the peeling of the abrasive grains 12, the work amount of the wrapping film 11 is increased, so that the finished surface roughness of the processed surface 65 is improved and the processing time is reduced. Shortening can be achieved.
[0063]
Further, the floating unit 130 includes a pair of spring members 75 and 76 for urging the resilient force to the convex shoes 71 from both sides along the direction in which the convex shoes 71 rotate. The force applied to the convex shoe 71 acts to rotate the convex shoe 71 in a direction opposite to the rotational direction of the work W, so that the work W is rotated only in one direction and wrapped. It is suitable for application when processing is performed.
[0064]
Further, since the pair of spring members 75 and 76 have different spring constants, a force that causes the convex shoe 71 to float in the direction opposite to the rotation direction of the work W is easily applied to the convex shoe 71. Can be granted.
[0065]
(Modification example)
Although the case where the processing surface 65 of the work W has an arc shape with a non-circular cross section as in the case of the cam lobe portion 61 of the cam shaft 60 has been described, the present invention is not limited to this case. For example, it goes without saying that the present invention can be applied to various other works W having a processing surface having a cylindrical cross section, such as a pin portion and a journal portion of a crankshaft.
[0066]
In the first embodiment, since the convex shoe 71 can be forcibly floated by the driving means 31 of the floating unit 30, the floating motion of the convex shoe 71 can be finely adjusted according to the rotational position of the workpiece W during processing. Can be controlled. For example, in the illustrated cam lobe portion 61, since it is required to finish the surface roughness of the top portion a and the event portions b1 and b2 with high accuracy, the position where the top portion a and the event portions b1 and b2 are processed. It is also possible to adopt a control in which the convex shoe 71 moves in a floating manner only while the work W is rotating. As described above, the convex shoe may be caused to float while the workpiece W makes one rotation, or the floating shoe may be caused to float only within an arbitrary rotation angle range while the workpiece W makes one rotation.
[0067]
Further, as the driving means 31 included in the floating means 30, the form using the operating rod 32, the link mechanism 33, the motor M4 and the like has been exemplified, but the present invention is not limited to this, and can be appropriately modified. For example, the convex shoe 71 may be forcibly floated using a hydraulic cylinder or the like that is operated by hydraulic pressure or pneumatic pressure. Further, the driving means 31 may be separately and independently connected to each of a plurality of (two upper and lower in the illustrated example) convex shoes 71.
[0068]
Further, in the second embodiment, a form in which a coil spring is used as the pair of spring members 75 and 76 included in the floating means 30 is exemplified, but the present invention is not limited to this, and can be appropriately modified. A spring member such as a leaf spring, a disc spring, or a rubber material having elasticity may be used as long as the force that causes the convex shoe 71 to perform a floating motion in a direction opposite to the rotation direction of the work W acts on the convex shoe 71. May be used.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a lapping apparatus according to a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view showing a closed state of upper and lower arms provided in the lapping apparatus so as to be openable and closable.
FIG. 3 is a schematic sectional view showing an open state of upper and lower arms.
FIG. 4 is a configuration diagram conceptually showing a floating unit of the lapping apparatus.
FIGS. 5 (A) and 5 (B) are views for explaining the action of a convex shoe capable of freely floating movement of shaking the head.
FIG. 6A is a perspective view showing an example of a camshaft as a workpiece to be wrapped, and FIG. 6B is a view provided for explaining each part of a cam lobe portion of the camshaft.
FIG. 7 is a schematic block diagram showing a control system of the lapping apparatus according to the present invention.
FIG. 8 is a configuration diagram conceptually showing a floating unit according to a second embodiment of the present invention.
FIGS. 9A to 9D are views for explaining the operation of the floating unit.
[Explanation of symbols]
1. Lapping machine
11 ... Wrapping film
30, 130 ... Floating unit (floating means)
31 ... Drive means
40 ... Rotary drive unit (rotary drive means)
50 ... oscillation unit
60 ... Camshaft (work)
61 ... Cam lobe part
71 ... convex shoe
72 ... swing pin (support shaft)
73 ... Shoe case
74 spring for work clamp
75, 76: A pair of spring members
100 ... controller (control means)
M1 ... Spindle motor
M2: Motor for oscillation
M4: Motor
S1: Rotary encoder (detection means)
S2, S3 ... Rotary encoder
S4 ... Sensor
W… Work

Claims (6)

In a lapping machine that performs lapping on the machining surface of a rotating workpiece,
A wrapping film in which abrasive grains are provided on one surface of a thin base material,
A convex shoe formed on a circular arc surface having a convex cross section and having a convex tip for pressing the abrasive grain surface of the wrapping film against the work and held via a support shaft so as to be freely rotatable,
Floating means for rotating the convex shoe in accordance with the rotation of the work,
A lapping apparatus wherein a contact point between the convex shoe and the wrapping film and a contact point between the wrapping film and the work are dispersed. The floating means includes a driving means connected to the convex shoe and forcibly rotating the convex shoe,
Rotation driving means for rotating the work,
Detecting means for detecting the rotational position of the work,
The operation of the driving unit is controlled so as to change a contact point between the convex shoe and the wrapping film and a contact point between the wrapping film and the work according to a rotational position of the work during processing. The lapping apparatus according to claim 1, further comprising a control unit that performs the wrapping processing. The floating means includes a pair of spring members for biasing the convex shoe from both sides along the direction in which the convex shoe rotates.
The force applied by the pair of spring members to the convex shoe acts to rotate the convex shoe in a direction opposite to a rotation direction of the workpiece. The wrapping processing device as described. The lapping apparatus according to claim 3, wherein the pair of spring members have different spring constants. The lapping apparatus according to claim 1, wherein the wrapping film is non-stretchable and deformable. A lapping method for applying a lapping process by pressing an abrasive surface of a lapping film against a rotating work,
A convex shoe having a convex tip formed in an arcuate surface with a convex cross section and held via a support shaft so as to be freely rotatable is rotated according to the rotation of the work, and the convex shoe is rotated. A contact point between the wrapping film and the workpiece, and a contact point between the wrapping film and the workpiece.

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