JP3682877B2 - Lapping device and lapping method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a lapping apparatus and a lapping process method for film lapping (hereinafter simply referred to as lapping) on a work surface of a workpiece by a lapping film with abrasive grains (hereinafter also simply referred to as film).
[0002]
[Prior art]
For example, when finishing a workpiece having an arc-shaped outer peripheral surface such as a cam lobe portion or journal portion of a camshaft or a journal portion or pin portion of a crankshaft, a lapping film recently provided with abrasive grains on one side Wrapping process.
[0003]
In this lapping process, the work surface of the work is covered with a wrapping film, the film is pressed with a shoe from the back, and the work is processed on the abrasive surface of the film while rotating the work while the film is pressed against the work. In addition to a mechanism that presses a shoe against a workpiece through a film, the lapping machine is a mechanism that rotates the workpiece, and an oscillation that imparts oscillation along the axial direction of the workpiece to at least one of the workpiece and the wrapping film. It has a mechanism (for example, refer to Patent Document 1).
[0004]
The shoe is classified into a convex shoe and a concave shoe from the shape of its tip, and the shoe shown in Patent Document 1 is formed on an arc surface having a convex cross section and presses the abrasive surface of the wrapping film against the workpiece. A convex shoe having a convex tip. This convex shoe is fixed to the apparatus side so that it cannot perform a rotational movement (hereinafter also referred to as a floating movement that shakes the head).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-237116 (see FIGS. 1 and 2)
[0006]
[Problems to be solved by the invention]
Since the convex shoe cannot perform a floating motion that swings its 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 in the lapping process.
[0007]
For this reason, there is a problem that the shoe pressing force concentrates on one point of the convex shoe, and the shoe is locally damaged. Furthermore, 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 peeling of the abrasive grains are promoted.
[0008]
The present invention has been made to solve the problems associated with the prior art described above, and when a convex shoe is used, local damage to the convex shoe is reduced and local clogging or grinding of the wrapping film is reduced. It is an object of the present invention to provide a lapping apparatus and a lapping process method that can reduce particle peeling.
[0009]
[Means for Solving the Problems]
The object of the present invention is achieved by the following means.
[0010]
The present invention is a lapping apparatus for lapping a machining surface of a rotating workpiece,
A wrapping film in which abrasive grains are provided on one surface of a thin substrate;
A convex shoe that is formed on a circular arc surface having a convex cross section and has a convex tip portion that presses the abrasive grain surface of the wrapping film against the workpiece and is held via a support shaft so as to be freely rotatable;
Floating means for rotating the convex shoe according to the rotation of the workpiece,
The lapping apparatus is characterized in that the contact points between the convex shoe and the wrapping film and the contact points between the wrapping film and the workpiece are dispersed.
[0011]
Further, the present invention is a lapping method for performing lapping by pressing the abrasive surface of the lapping film against a rotating workpiece,
A convex shoe provided with a convex tip formed on a circular 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 workpiece, and the convex shoe And a contact point between the wrapping film and the workpiece, and a contact point between the wrapping film and the workpiece is dispersed.
[0012]
【The invention's effect】
According to the lapping apparatus and lapping method of the present invention, it is possible to reduce the local damage of the convex shoe and to reduce clogging of the wrapping film and peeling of the abrasive grains.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0014]
(First embodiment)
FIG. 1 is a schematic configuration diagram illustrating a lapping apparatus 1 according to a first embodiment of the present invention, and FIG. 2 illustrates a closed state of upper and lower arms 22 and 23 provided in the lapping apparatus 1 so as to be openable and closable. 3 is a schematic cross-sectional view showing an open state of the upper and lower arms 22 and 23, FIG. 4 is a block diagram conceptually showing the floating unit 30 of the lapping apparatus 1, and FIGS. ) Is a diagram for explaining the operation of the convex shoe 71 that allows a floating motion to swing the head. 6A is a perspective view showing an example of the camshaft 60 as the workpiece W to be lapped, and FIG. 6B is a diagram for explaining each part in the cam lobe portion 61 of the camshaft 60. is there. For convenience of explanation, the axial direction of the camshaft 60 (left-right direction in FIG. 1) is defined as the X direction, and the horizontal direction orthogonal to the X direction (direction orthogonal to the paper surface in FIG. 1) is defined as the Y direction. The vertical direction (vertical direction in FIG. 1) perpendicular to the X direction is defined as the Z direction.
[0015]
The lapping apparatus 1 of this embodiment will be outlined with reference to FIGS. 1 to 4. A lapping film 11 in which abrasive grains are provided on one surface of a non-stretchable and deformable thin substrate, and the lapping film 11. A convex shoe 71 that is pressed against the workpiece W and swings freely so that it can freely move, and a floating unit 30 that floats the convex shoe 71 in accordance with the rotation of the workpiece W. And an oscillating unit 40 that oscillates along the axial direction of the workpiece W to at least one of the workpiece W and the wrapping film 11. A 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 driving means 31 connected to the convex shoe 71 and forcibly moving the convex shoe 71 (see FIG. 4).
[0016]
As shown in FIG. 6A, the workpiece W can include a camshaft 60, and the outer peripheral surface of the cam lobe portion 61 in the camshaft 60 becomes a processing surface 65 on which lapping is performed. As shown in FIG. 6B, the cam lobe portion 61 is continuous with the base portion d forming the base circle, the top portion a that defines the cam lift, and both sides of the top portion a, and starts or closes the valve of the engine. The event parts b1 and b2 to be started are provided with a plurality of parts of the lamp parts c1 and c2 that approach the event parts b1 and b2 from the base part d. Although the base portion d has a constant curvature radius, the event portions b1 and b2 are substantially linear, so the curvature radius is very large, and the top portion a has a relatively small curvature radius. The machining surface 65 of the cam lobe portion 61 has an arc shape with a non-circular cross section in which the radius from the rotation center to one portion is different from the radius to the other portion.
[0017]
Corresponding to the position of the cam lobe 61, a plurality of pairs of upper and lower arms 22 and 23 are arranged (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 head stock 42 that rotatably supports a main shaft 41, a chuck 43 that is connected to the tip of the main shaft 41 and grips one end of a camshaft 60, and a belt attached to the main shaft 41. And a tail stock 46 including a center 45 that supports the other end of the camshaft 60. The camshaft 60 is rotationally driven by the rotation of the main shaft motor M1 being transmitted through 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 detection means) for detecting the rotational position of the workpiece W during machining is attached to the main shaft 41. Each of the head stock 42 and the tail stock 46 is provided on tables 47 and 48 that are slidable along the Y direction, and these tables 47 and 48 are arranged on a table 49 that is slidable along the X direction. ing. In order to set the camshaft 60 between the headstock 42 and the tailstock 46, or to move the camshaft 60 to the processing position, the respective tables 47, 48, 49 are moved.
[0020]
The oscillation unit 50 includes an eccentric rotator 51 that contacts the end surface of the table 49, and an oscillation motor M <b> 2 that rotationally drives the eccentric rotator 51. The oscillation unit 50 includes an elastic means 52 such as a spring for biasing a resilient force that presses the table 49 toward the eccentric rotator 51 so that the end surface of the table 49 and the eccentric rotator 51 are always in contact with each other. 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 oscillation amplitude is determined based on the amount of eccentricity of the eccentric rotating body 51 with respect to the axis of the oscillation motor M2. The amount of eccentricity is about 1 mm, and the amplitude of oscillation is about 2 mm. The eccentric amount of the eccentric rotating body 51 can be adjusted by known means such as changing the number of inserted adjustment plates (not shown). A rotary encoder S <b> 2 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 this embodiment, the base material is made of a highly non-stretchable material, 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, etc.) having a particle diameter of several μm to 200 μm are attached by an adhesive. The abrasive grains may be bonded to the entire surface of the base material, or may be formed by intermittently forming non-abrasive grain regions having a predetermined width. On the other surface of the base material, a back coating for attaching a resistance material (not shown) made of rubber, synthetic resin or the like, or a non-slip process is applied to the convex shoe 71 in some cases.
[0022]
With reference to FIGS. 2 and 3, the wrapping film 11 is pulled out from the supply reel 15 and attached to a pair of first guide rollers R <b> 1 provided at the tip of the upper arm 22 and an inner position of the upper arm 22. The second guide roller R2, the third guide roller R3 attached to the inner position of the lower arm 23, the pair of fourth guide rollers R4 provided at the tip of the lower arm 23, etc. It is wound on a take-up reel 16. A motor M3 is connected to the take-up reel 16. When the motor M3 is operated and the take-up reel 16 is rotated, the wrapping film 11 is sequentially fed out from the supply reel 15. In order to detect the feed 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 in the vicinity of 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 paired upper arm 22 and lower arm 23 are rotatably provided via a support pin 24 so that the tip portion where the convex shoe 71 is disposed can be opened and closed relatively in the Z direction. One end of a fluid pressure cylinder 25 that is operated by hydraulic pressure or air pressure is pin-connected to the rear end portion of the upper arm 22, and the tip of a piston rod 26 is pin-connected to the rear end portion of the lower arm 23. When the piston rod 26 is extended from the contracted state, the upper and lower arms 22 and 23 are pivoted about the support pins 24 in the direction in which the tip ends are closed, and are in 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 are rotated in the direction in which the distal ends are opened, and are in the open state shown in FIG. The upper and lower arms 22, 23 are rotated together with the wrapping film 11, and the convex shoe 71 comes into contact with 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 that is formed on an arc surface having a convex cross section and presses the abrasive grain surface of the wrapping film 11 against the workpiece W. In the illustrated embodiment, the convex shoe 71 is configured to be capable of floating movement and to change the contact point that contacts the processing surface 65 of the cam lobe portion 61 via the wrapping film 11. In the present specification, the indirect contact of the convex shoe 71 with the outer peripheral surface of the workpiece W via the film 11 is abbreviated as “contact”.
[0025]
The convex shoe 71 is held by the shoe case 73 via a swinging pin (corresponding to a support shaft) 72 so that the floating motion of swinging the neck is free. The shoe case 73 is housed in a recess 27 formed at the tip of the upper and lower arms 22 and 23 so as to be movable forward and backward with respect to the workpiece W. The shoe case 73 moves while its outer surface is guided by the inner surface of the recess 27. A work clamping spring 74 made of a compression coil spring is disposed on the back surface of the shoe case 73. The convex shoe 71 is pressed against the processing surface 65 via the wrapping film 11 by the elastic force of the work clamping spring 74. The upper and lower swing pins 72 are positioned 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 includes a link mechanism 33 schematically shown by a two-dot chain line in which one end is pin-connected to the convex shoe 71 and the other end is pin-connected to an operation rod 32 that is movable forward and backward. And a motor M4 that moves the operating rod 32 forward and backward. In order to convert the rotation operation of the motor M4 into the 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 advancing / retreating 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 actuating rod 32, the link mechanism 33, and the motor M4 described above constitute the driving means 31 that is connected to the convex shoe 71 and forcibly moves the convex shoe 71 in a floating manner. When the convex shoe 71 is forcibly moved in a floating motion, the convex shoe 71 is always pressed against the cam lobe portion 61 and the abrasive grain surface of the wrapping film 11 is pressed against the processing surface 65. . Further, the position of the convex shoe 71 shown in FIG.
[0027]
The combination of the directions in which each of the upper and lower convex shoes 71 performs a floating movement can be arbitrarily determined. For example, when the upper convex shoe 71 floats clockwise from the initial position around the swing pin 72 as an example, the lower convex shoe 71 rotates from the initial position around the swing pin 72 as a center. Floating motion may be performed in the rotating direction, or floating motion may be performed in the counterclockwise direction. However, the floating movement of the convex shoe 71 is made according to the rotation of the workpiece W. Specifically, the convex shoe is changed so that the contact point between the convex shoe 71 and the wrapping film 11 and the contact point 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 that allows the floating motion to swing the head will be described. FIG. 5 (A) conceptually shows a state when the convex shoe 71 has made a maximum floating movement clockwise from the initial position around the swing pin 72, and FIG. The state when the shoe 71 has made the maximum floating movement counterclockwise around the swing pin 72 from the initial position is conceptually shown. In addition, the code | symbol 12 in the figure has shown the abrasive grain of the wrapping film 11. FIG.
[0029]
As shown in FIG. 5A, when the convex shoe 71 has a maximum floating motion in the clockwise direction, the pressed convex shoe 71 and the back surface of the wrapping film 11 are pressed against each other at the contact point A1, and the wrapping film 11 The abrasive grain surface and the workpiece W are in pressure contact at the contact point A2. On the other hand, as shown in FIG. 5 (B), when the convex shoe 71 performs the maximum floating movement in the counterclockwise direction, there is no slip between the convex shoe 71 and the wrapping film 11, so that the convex shoe pressed is pressed. 71 and the back surface of the wrapping film 11 are in pressure contact at the contact point B1, and the abrasive grain surface of the wrapping film 11 and the workpiece W are in pressure contact at the contact point B2.
[0030]
Therefore, the contact points between the convex shoe 71 and the wrapping film 11 are dispersed in the range of the contact points A1 to B1. Furthermore, the contact points between the wrapping film 11 and the workpiece W are dispersed in the range of the contact points A2 to B2. When this range is expressed by an angle θ with the swing pin 72 as the center, θ = 2α when the swinging angles in the clockwise direction and the counterclockwise direction from the initial position of the convex shoe 71 are α. .
[0031]
In this way, 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 is not concentrated on one point of the convex shoe 71. Damage is not severe locally. Furthermore, since the contact point between the wrapping film 11 and the workpiece W is dispersed within a certain range, the shoe pressing force is not concentrated on one point of the wrapping film 11. Peeling 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, the rotary encoders S1, S2, S3 and the sensor S4 are connected to a controller 100 (corresponding to a control means) mainly composed of a CPU and a memory, and the rotational position of the cam lobe 61 during processing The detection signals relating to the advance / retreat position of the actuating rod 32 that determines the floating position of the convex shoe 71 are respectively input to the controller 100. A detection signal related to the rotation speed of the spindle motor M1 that determines the workpiece rotation speed Vw and 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 convex shoe 71 to perform a floating motion according to the rotational position of the cam lobe portion 61 detected by the rotary encoder S1.
[0034]
The change control of the floating motion of the convex shoe 71 is performed according to the contact position between the convex shoe 71 and the wrapping film 11 and the contact between the wrapping film 11 and the cam lob portion 61 according to the rotational position of the cam lobe portion 61 during processing. This is done by controlling the operation of the drive means 31 of the floating unit 30 to change the point.
[0035]
Specifically, the controller 100 moves the operating rod 32 forward and backward according to the rotational position of the cam lobe portion 61 during processing, operates the link mechanism 33 accordingly, and the convex shoe 71 is centered on 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. As a result, the contact points between the convex shoe 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 workpiece W are dispersed. Are dispersed within a certain range (for example, contact point A2 to contact point B2 shown in FIG. 5).
[0036]
Next, the operation of this 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 contracts 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 rotate in a direction to close the upper and lower arms 22 and 23. 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 and 23 are opened and rotated, the motor M3 is operated to rotate the take-up reel 16. The wrapping film 11 moves by a predetermined amount, and a new abrasive grain surface is set on the processed surface 65. Thereafter, when a lock device provided in the vicinity of 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 locking device in the vicinity of the take-up reel 16 is locked, the wrapping film 11 is given a tension and is not loosened.
[0039]
When the camshaft 60 is clamped, the elastic force of the work clamping spring 74 is urged to press the convex shoe 71 toward the cam lobe 61, and the abrasive grain surface of the wrapping film 11 is pressed against the processing surface 65.
[0040]
Then, when the oscillation unit 50 is operated to give the camshaft 60 oscillation along the axial direction, and the rotation drive unit 40 is operated to rotate the camshaft 60 about the axis, the shoe holding the convex shoe 71 is held. The processing surface 65 of the cam lobe 61 is lapped while the case 73 moves forward and backward in the recess 27 following the rotation of the cam lobe 61.
[0041]
During this processing, the rotary encoder S1 detects the rotational position of the cam lobe portion 61, and the controller 100 controls the convex shoe 71 to perform a floating motion in accordance with the detected rotational position of the cam lobe portion 61. That is, the controller 100 controls the operation of the motor M4, moves the operating rod 32 forward and backward, operates the link mechanism 33 accordingly, and causes the convex shoe 71 to perform a floating motion around the swing pin 72.
[0042]
Thereby, the contact point between the convex shoe 71 and the wrapping film 11 is dispersed within a certain range, and further, the contact point between the wrapping film 11 and the workpiece W is dispersed within a certain range.
[0043]
During the lapping process, the camshaft 60 is rotated forward by a set number of times (for example, 5 times) and then reversely rotated by the same set number of times. By changing the rotation direction, clogging of the wrapping film 11 is eliminated and the performance is maintained.
[0044]
In this way, 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 is not concentrated on one point of the convex shoe 71. The local damage can be reduced.
[0045]
Furthermore, since the contact point between the wrapping film 11 and the workpiece W is dispersed within a certain range, the shoe pressing force is not concentrated on one point of the wrapping film 11, so that the wrapping film 11 is locally clogged or ground. The peeling of the grains 12 can be reduced. This means that when the work amount of the wrapping film 11 is focused, the work surface is dispersed and thus the work amount is increased. Therefore, as a result of increasing the work amount of the wrapping film 11, 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 number of cam lobe portions 61, and lapping is performed on these cam lobe portions 61 all at once. When the lapping process is completed, the fluid pressure cylinder 25 is operated to contract the piston rod 26, and the upper and lower arms 22 and 23 are rotated in the opening direction, so that the camshaft 60 can be taken out. If another camshaft 60 is set after the camshaft 60 is taken out, the same lapping process can be started.
[0047]
As described above, according to the lapping apparatus 1 of the first embodiment described above, the wrapping film 11 and the convexity that presses the abrasive grain surface of the wrapping film 11 formed on the circular arc surface having a convex cross section against the workpiece W. A convex shoe 71 that is provided with a pin tip and is held via a swing pin 72 so as to be freely rotatable, and a floating unit 30 that rotates the convex shoe 71 in accordance with the rotation of the workpiece W. Since 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 dispersed, when the convex shoe 71 is used, It is effective in reducing local damage and reducing clogging of the wrapping film 11 and peeling of the abrasive grains 12. In addition, the amount of work of the wrapping film 11 is increased through reducing local clogging of the wrapping film 11 and peeling of abrasive grains. As a result, the finished surface roughness of the processed surface 65 is improved and the processing time is shortened. Can be achieved.
[0048]
The floating unit 30 includes a driving unit 31 that is connected to the convex shoe 71 and forcibly rotates the convex shoe 71, detects the rotational position of the workpiece W, and the rotational drive unit 40 that rotationally drives the workpiece 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 workpiece W are changed according to the rotary encoder S1 to be rotated and the rotational position of the workpiece W during processing. Since the controller 100 for controlling the operation of the driving unit 31 is further provided, in addition to the above-described effects, there is an effect that 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, a suitable wrapping process can be performed on the workpiece W.
[0050]
Further, the lapping apparatus 1 of the present embodiment is a lapping process method for performing lapping by pressing the abrasive grain surface of the lapping film 11 against a rotating workpiece W, and a convex shape formed on a circular arc surface having a convex cross section. A convex shoe 71 having a front end portion and held via a swing pin 72 so as to be freely rotated is rotated according to the rotation of the work W, and the contact between the convex shoe 71 and the wrapping film 11 is achieved. The present invention embodies a lapping method for dispersing points and contact points between the wrapping film 11 and the workpiece W. As described above, when the convex shoe 71 is used, local damage to the convex shoe 71 is caused. As well as the effect of reducing local clogging of the wrapping film 11 and peeling of the abrasive grains 12, and improving the finished surface roughness of the processed surface 65. It is possible to shorten the machining time while.
[0051]
(Second Embodiment)
FIG. 8 is a configuration diagram conceptually showing the 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. In addition, the same code | symbol is attached | subjected to the member which is common in 1st Embodiment, and the description is abbreviate | omitted. In FIG. 9, only the movement of the upper convex shoe 71 is shown.
[0052]
The floating unit 30 of the first embodiment includes a driving unit 31 that forcibly causes the convex shoe 71 to perform a floating movement, and is suitably applied when lapping is performed by changing the rotation direction of the workpiece W in both forward and reverse directions. Is done. On the other hand, the floating unit 130 according to the second embodiment is preferably applied when the workpiece W is rotated only in one direction to perform lapping. This will be described below.
[0053]
Similarly to the first embodiment, the lapping apparatus according to the second embodiment includes a convex tip portion that is formed on a circular arc surface having a convex cross section and presses the abrasive grain surface of the wrapping film 11 against the workpiece W. It has a convex shoe 71 that is held via a swing pin 72 so that a floating motion that swings the head is free, and a floating unit 130 that causes the convex shoe 71 to perform a floating motion in accordance with the rotation of the workpiece W.
[0054]
As shown in FIG. 8, the floating unit 130 includes a pair of spring members 75 and 76 that urge elastic force to the convex shoe 71 from both sides along the direction in which the convex shoe 71 moves. 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 a floating motion in a direction opposite to the rotation direction of the workpiece W. That is, assuming that the direction of rotation of the workpiece W is the clockwise direction indicated by the arrow r, the force applied to the convex shoe 71 by the pair of spring members 75 and 76 directs the upper convex shoe 71 leftward in the figure. Thus, the lower convex shoe 71 acts to move in the right direction in the figure.
[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. In the case where the spring members 75 and 76 are constituted by, for example, a tension coil spring, it is only necessary to satisfy the relationship of the spring constant of the spring member 75> the spring constant of the spring member 76. When the spring members 75 and 76 are constituted by compression coil springs May satisfy the relationship of the spring constant of the spring member 75 <the spring constant of the spring member 76.
[0056]
Also in the second embodiment, when the oscillation unit 50 is operated to apply oscillation along the axial direction to the camshaft 60 and the rotation drive unit 40 is operated to rotate the camshaft 60 about the axis, the convexity The processing surface 65 of the cam lobe portion 61 is lapped while the shoe case 73 holding the shoe 71 moves forward and backward in the recess 27 following the rotation of the cam lobe portion 61.
[0057]
During this processing, as shown in FIGS. 9A to 9D, the workpiece W is rotated 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 to cause the convex shoe 71 to perform a floating motion in a direction opposite to the rotation direction of the workpiece W.
[0058]
As the workpiece W rotates, the convex shoe 71 performs a floating motion in the right direction in the drawing (FIGS. 9A to 9C). When the processing part moves from the top part a having a relatively small radius of curvature to the substantially linear event parts b1 and b2, the convex shoe 71 moves in the left direction in the figure by the action of the spring member 75. (FIG. 9D).
[0059]
Thereby, the contact point between the convex shoe 71 and the wrapping film 11 is dispersed within a certain range, and further, the contact point between the wrapping film 11 and the workpiece W is 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 is reduced. Since it does not concentrate on one point, the local damage of the convex shoe 71 can be reduced.
[0061]
Furthermore, since the contact point between the wrapping film 11 and the workpiece W is dispersed within a certain range, the shoe pressing force is not concentrated on one point of the wrapping film 11, so that the wrapping film 11 is locally clogged or ground. The peeling of the grains 12 can be reduced. Further, as a result of increasing the work amount of the wrapping film 11, 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 tip portion that is formed on the circular arc surface having a convex cross section and presses the abrasive grain surface of the wrapping film 11 against the workpiece W. A convex shoe 71 that is held via a swing pin 72 so as to be freely rotatable, and a floating unit 130 that rotates the convex shoe 71 in accordance with the rotation of the workpiece W. Since the contact points between 71 and the wrapping film 11 and the contact points between the wrapping film 11 and the workpiece W are dispersed, when the convex shoe 71 is used, local damage to the convex shoe 71 is caused. While reducing, local clogging of the wrapping film 11 and peeling of the abrasive grains 12 can be reduced. Further, the amount of work of the wrapping film 11 is increased through reducing local clogging of the wrapping film 11 and peeling of the abrasive grains 12, thereby improving the finished surface roughness of the processed surface 65 and reducing the processing time. It becomes possible to shorten.
[0063]
In addition, the floating unit 130 includes a pair of spring members 75 and 76 that bias the elastic force to the convex shoe 71 from both sides along the direction in which the convex shoe 71 rotates. The force applied to the convex shoe 71 acts to rotate the convex shoe 71 in the direction opposite to the rotation direction of the workpiece W, so that the workpiece W is rotated only in one direction for wrapping. It is suitable for application when processing.
[0064]
Further, since the pair of spring members 75 and 76 have different spring constants, a force that causes the convex shoe 71 to perform a floating movement in a direction opposite to the rotation direction of the workpiece W can be easily applied to the convex shoe 71. Can be granted.
[0065]
(Modification example)
Although the case where the machining surface 65 of the workpiece W has an arc shape with a non-circular cross section is shown like the cam lobe portion 61 of the camshaft 60, the present invention is not limited to this case. For example, it is needless to say that the present invention can be applied to other various workpieces W having a machining surface having a cylindrical cross section, such as a pin portion or a journal portion of a crankshaft.
[0066]
In the first embodiment, since the convex shoe 71 can be forcibly made to float by the driving means 31 of the floating unit 30, the floating motion of the convex shoe 71 is finely adjusted according to the rotational position of the workpiece W during processing. Can be controlled. For example, in the illustrated cam lobe part 61, it is required to finish the surface roughness of the top part a and the event parts b1 and b2 with high precision, so that the top part a and the event parts b1 and b2 are processed. It is also possible to employ a control that causes the convex shoe 71 to perform a floating movement only while the workpiece W is rotating. Thus, the convex shoe may move in a floating manner while the workpiece W makes one revolution, or the convex shoe may make a floating motion only in an arbitrary rotation angle range while the workpiece W makes one revolution.
[0067]
Moreover, although the form which used the action | operation rod 32, the link mechanism 33, the motor M4, etc. was illustrated as the drive means 31 contained in the floating means 30, it is not limited to this, It can change suitably. For example, the convex shoe 71 may be forcibly floated using a fluid pressure cylinder operated by hydraulic pressure or pneumatic pressure. In addition, the driving means 31 may be connected to each of a plurality of (two in the illustrated example) upper and lower convex shoes 71 independently.
[0068]
Moreover, in 2nd Embodiment, although the form which used a coil spring was illustrated as a pair of spring members 75 and 76 contained in the floating means 30, it is not limited to this, It can change suitably. A spring member such as a leaf spring, a disc spring, or an elastic rubber material may be used as long as the force that causes the convex shoe 71 to float in the direction opposite to the rotation direction of the workpiece W acts on the convex shoe 71. It 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 a lapping apparatus so as to be freely opened and closed.
FIG. 3 is a schematic cross-sectional view showing an open state of upper and lower arms.
FIG. 4 is a configuration diagram conceptually showing a floating unit of a lapping apparatus.
FIGS. 5 (A) and 5 (B) are diagrams for explaining the operation of a convex shoe that can freely swing and swing its head.
6A is a perspective view showing an example of a camshaft as a workpiece to be lapped, and FIG. 6B is a diagram for explaining each part in 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 block diagram conceptually showing a floating unit according to a second embodiment of the present invention.
FIGS. 9A to 9D are diagrams for explaining the operation of the floating unit.
[Explanation of symbols]
1 ... Lapping device
11 ... Wrapping film
30, 130 ... Floating unit (floating means)
31 ... Driving means
40: Rotation drive unit (rotation drive means)
50 ... Oscillation unit
60 ... Camshaft (work)
61 ... Cam lobe
71 ... Convex shoe
72 ... Oscillating pin (support shaft)
73 ... Shoe case
74 ... Work clamp spring
75, 76 ... A pair of spring members
100: Controller (control means)
M1 ... Spindle motor
M2 ... Oscillation motor
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 work surface of a rotating workpiece,
A wrapping film in which abrasive grains are provided on one surface of a thin substrate;
A convex shoe that is formed on a circular arc surface having a convex cross section and has a convex tip portion that presses the abrasive grain surface of the wrapping film against the workpiece and is held via a support shaft so as to be freely rotatable;
Floating means for rotating the convex shoe according to the rotation of the workpiece,
A lapping apparatus for dispersing a contact point between the convex shoe and the wrapping film and a contact point between the wrapping film and the workpiece. The floating means includes drive means connected to the convex shoe and forcibly rotating the convex shoe,
A rotation driving means for rotating the workpiece;
Detecting means for detecting the rotational position of the workpiece;
The operation of the driving means is controlled so as to change the contact point between the convex shoe and the wrapping film and the contact point between the wrapping film and the workpiece according to the rotational position of the workpiece during processing. The lapping apparatus according to claim 1, further comprising a control unit that performs the control. The floating means includes a pair of spring members that urge elastic force to the convex shoe from both sides along the direction in which the convex shoe rotates.
2. The force applied to the convex shoe by the pair of spring members acts to cause the convex shoe to rotate in a direction opposite to the rotation direction of the workpiece. The lapping apparatus 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 lapping film is non-stretchable and deformable. A wrapping method for performing wrapping by pressing the abrasive surface of a wrapping film against a rotating workpiece,
A convex shoe provided with a convex tip formed on a circular 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 workpiece, and the convex shoe And a contact point between the wrapping film and the workpiece, and a contact point between the wrapping film and the workpiece is dispersed.

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