JP3885907B2 - Piston ring processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piston ring processing apparatus capable of processing an outer peripheral surface of a piston ring with high accuracy.
[0002]
[Prior art]
Conventionally, piston rings used for engines, etc., are formed by laminating a number of non-circular rings formed in a substantially heart shape, and after processing the inner and outer peripheral surfaces into a predetermined shape, the two outer peripheral portions are cut in the axial direction. When the diameter is reduced and the cut portion is brought into close contact, a method of manufacturing a piston ring whose outer peripheral surface is a perfect circle is generally adopted, and an apparatus for processing the inner and outer peripheral surfaces of a non-circular ring is, for example, Japanese Patent Application Laid-Open No. 54-21691, Japanese Patent Publication No. 6-75814, and the like.
[0003]
The machining apparatus described in the above-mentioned Japanese Patent Application Laid-Open No. 54-21691 is a tool support that can be displaced in the radial direction in accordance with the degree of the non-circular curve of the piston ring assembly and the piston ring assembly. And at least two or more electromechanical step drive means controlled by a computer and installed back and forth in the direction of operation of the piston ring via a work shaft. By controlling the step driving means by a computer while rotating the assembly, the inner and outer peripheral surfaces of the workpiece having a non-circular curve formed by a free curve can be simultaneously processed with high accuracy.
[0004]
On the other hand, in the numerically controlled lathe described in Japanese Patent Publication No. 6-75814, a cutting tool for cutting a workpiece is attached to a carriage that can be moved forward and backward in the direction of the workpiece by a linear motor. The outer periphery of the skirt of the workpiece, such as a piston, is cut by numerical control using a plurality of rotating members and a biasing device provided in the guide portion that supports the reciprocating movement of the carriage. Since the reaction force generated in the tool during the cutting process is supported by the rotating member and the biasing device, the carriage can be reciprocated in the absence of rattling or blurring. It has the effect of becoming possible.
[0005]
[Problems to be solved by the invention]
However, the conventional processing method has the following problems.
That is, the non-circular material a to be processed into the piston ring is cut in the axial direction at two locations on the outer peripheral surface to reduce the diameter so that the outer peripheral surface becomes a center circle when the cut portions are brought into close contact with each other. The shape of the tool c is as shown in FIG. 1 (a). When the inner and outer peripheral surfaces of the workpiece a are turned by a conventional method, the cutting edge of the tool c for each rotation angle of the rotating workpiece a. d is moved in the X-axis and U-axis directions by the stroke shown in FIG.
[0006]
For this reason, when the cutting edge d of the tool c reaches the starting point e of the recess b, the feed speed of the cutting edge d has been changed from “0” to the rotation center O direction so as to follow the recess b. As shown in FIG. 1, at this time, a large acceleration is generated in the tool support means to which the tool c is attached as shown in FIG.
After the cutting edge d of the tool c reaches the lowest part (rotation angle 0 °) of the recess b, the cutting edge d of the tool c is moved away from the rotation center O until reaching the end point f of the recess b. As shown in (c), the tool is moved suddenly. At this time as well, a large acceleration is generated in the tool support means to which the tool c is attached.
[0007]
As a result of this change in acceleration, vibration as shown by the curve A in FIG. 2 is generated in the tool support means for supporting each tool c, and the work support means for supporting the work a is shown in curve B in FIG. However, since the vibration waveforms (amplitude and frequency) of the tool support means for supporting the tool c and the work support means for supporting the work a are different, the difference between the waveforms (the hatched line in FIG. 2) has an influence on the machining accuracy of the workpiece a, and the machined surface becomes as shown in FIG.
[0008]
The present invention has been made in order to solve such a problem. By adopting a structure in which the vibration waveforms of the workpiece support means and the tool support means are substantially the same, a piston capable of high-precision machining is provided. An object of the present invention is to provide a ring processing apparatus.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a piston ring machining apparatus for machining an inner and outer peripheral surface of a work having an inner and outer peripheral surface formed of a non-circular curve.
A Z-axis slide which is movable in the vertical direction (Z-axis direction) by the Z-axis drive means and is provided with an upper work support means and a lower work support means spaced apart in the vertical direction ;
A C-axis driving means for rotating the workpiece through the workpiece support means,
A tool for machining the outer peripheral surface of the workpiece, an outer peripheral machining means provided on the X-axis bracket so as to be movable in the X-axis direction orthogonal to the axis of the workpiece;
Not restrict movement of the Z-axis direction of the Z axis slide, and to restrain movement of the direction perpendicular to the Z-axis direction, between the connecting means for connecting between the Z-axis slide and the X-axis bracket It is composed.
[0010]
With the above structure, the acceleration is rapidly changed, the Z-axis slide side for supporting the workpiece, the vibration in the X-axis bracket periphery grinding means mounted with the tool occurs, the Z-axis slide and periphery grinding means Since the X-axis brackets are connected by connecting means, the vibration waveform of the Z-axis slide and the vibration waveform of the outer peripheral processing means are almost the same, and the displacement difference is very small. Can be improved.
[0011]
The invention of claim 2, wherein in order to achieve the above object, the connecting means, provided in parallel with the Z axis, and both ends and a guide rod which is fixed to the Z axis slide, slidably in the guide rod it is fitted inserted, and is a more configuration and guide bracket fixed to the X-axis bracket.
[0012]
With the above configuration, the Z-axis slide and the X-axis bracket of the outer peripheral machining means are connected without restricting the movement of the Z-axis slide, and the vibration waveform generated in the Z-axis slide and the waveform generated in the outer peripheral machining means are It can be almost the same.
[0013]
In order to achieve the above object, according to a third aspect of the present invention, the connecting means comprises a linear guide rail provided between the Z-axis slide and the X-axis bracket of the outer peripheral machining means.
[0014]
With the above configuration, the connecting means can be configured with a ready-made linear guide rail, so that it can be implemented easily and inexpensively.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of the present invention will be described in detail with reference to the drawings shown in FIG.
In these drawings, reference numeral 1 denotes a processing apparatus main body. A column 1b is installed on a bed 1a, and a Z-axis slide 2 that can be moved in a vertical movement direction (Z-axis direction) by a Z-axis driving means 3 is provided on the front side of the column 1b. Is provided.
The Z-axis slide 2 is supported on a guide rail 1c made of a ball-type linear guide installed in the Z-axis direction on the front surface of the column 1b, and a Z-axis motor 4 made of a servo motor installed on the top of the column 1b. Is moved up and down.
[0016]
That is, a screw shaft 5 made of a ball screw is connected to the rotary shaft 4a of the Z-axis motor 4 as shown in FIG. 6, and a nut member 5a fixed to the Z-axis slide 2 is screwed to the screw shaft 5. The Z-axis slide 4 can be moved up and down along the guide rail 1c by rotating it forward and backward with the screw shaft 5 by the Z-axis motor 4, and a wire is placed above the Z-axis slide 2. One end of the rope 6 such as a rope is bound.
The intermediate portion of the rope 6 is circumvented by the pulley 7 rotatably supported on the column 1b, and the other end of the rope 6 is provided with a counterweight 8 provided on the rear side of the column 1b. The Z-axis slide 2 can be moved up and down by a small-capacity Z-axis motor 4.
[0018]
The Z-axis slide 2 is provided with an upper work support means 10 and a lower work support means 11 that are spaced apart in the vertical direction.
As shown in FIG. 7, the upper work support means 10 is provided below the hydraulic cylinder 12 provided at the top of the Z-axis slide 2, and below the piston 12 a accommodated in the upper part of the hydraulic cylinder 12. It has an upper spindle 10a.
[0019]
The upper spindle 10a has a cylindrical shape, and is supported by a lower portion of the hydraulic cylinder 12 through a plurality of bearings 13 so as to be vertically movable and rotatable, and a ring 10b fitted to the outer peripheral portion of the upper spindle 10a. The lower surface side of the piston 12a is in contact with the upper surface of the hydraulic cylinder 12 through the thrust bearing 14, and the upper spindle 10a is pressurized downward through the piston 12a by supplying hydraulic pressure to the hydraulic chamber 12b of the hydraulic cylinder 12. It can be done.
A fixed shaft 10 c whose upper end is fixed to the upper surface of the hydraulic cylinder 12 is provided at the center of the hydraulic cylinder 12.
The lower end side of the fixed shaft 10c passes through the piston 12a and reaches the center of the upper spindle 10a. The upper spindle 10a is urged upward via a bearing 14 on a spring seat 10d provided at the lower end. A plurality of compression springs 10e are provided.
[0020]
An upper clamp head 10f for clamping the workpiece 16 between lower clamp heads 11f provided on the lower workpiece support means 11 is provided at the lower portion of the upper spindle 10a, and an outer peripheral portion of the upper spindle 10a is The driven gear 18b of the gear train 18a constituting the C-axis drive means 18 is keyed.
As shown in FIG. 6, the C-axis driving means 18 has a C-axis motor 19 made of a servo motor at the top of the column 1b. The C-axis motor 19 is connected to the input shaft 20a of the speed reducer 20. .
The input shaft 20a is provided with a flywheel 20b that stabilizes rotation so as not to cause uneven rotation of the workpiece 16 during processing. The output shaft 20c of the speed reducer 20 is the upper end of a drive shaft 18c that is a spline shaft. The drive shaft 18c can be rotated forward and backward by the C-axis motor 19 via the speed reducer 20.
[0021]
The drive shaft 18c is rotatably supported in the vertical direction so as to be parallel to the axis of the workpiece 16, and the gear trains 18a provided in the upper workpiece support means 10 and the lower workpiece support means 11 respectively at the intermediate portion and the lower end portion. The drive gear 18d is spline engaged.
These drive gears 18d are engaged with driven gears 18b provided on the outer peripheral portion of the upper spindle 10a and the outer peripheral portion of the lower spindle 11a via an intermediate gear 18e, and the drive shaft 18c and the gear train 18a are connected by the C-axis motor 19. Thus, the upper spindle 10a and the lower spindle 11a can be synchronously rotated in the same direction.
[0022]
The lower spindle 11a is also formed in a cylindrical shape like the upper spindle 10a, and is rotatably supported on the Z-axis slide 2 side via a bearing 21, and the Z-axis slide 2 and the lower spindle 11a A thrust bearing 22 is interposed between the driven gear 18b keyed to the outer periphery.
A lower clamp head 11f that clamps the workpiece 16 between the upper clamp head 10f attached to the upper spindle 10a is provided above the lower spindle 11a.
[0023]
When the upper spindle 10a and the lower spindle 11a are driven to rotate synchronously by the C-axis motor 19, rotation unevenness occurs in the upper and lower spindles 10a and 11a due to the spline of the drive shaft 18c and the backlash of the gear train 18a. Deviation occurs.
In order to prevent this, at the time of machining the workpiece 16, the plate 11g of the lower spindle 11a can be fixed by a lock means (not shown) such as Loctite with the backlash of the upper and lower gear trains removed.
[0024]
On the other hand, an outer peripheral processing means 24 for processing the outer peripheral surface of the workpiece 16 is provided at a substantially intermediate portion of the column 1b, and an inner peripheral surface processing means for processing the inner peripheral surface of the work 16 simultaneously with the outer peripheral surface on the bed 1a. 25 is installed.
As shown in FIG. 8, a cylindrical guide member 24a is horizontally fixed to an X-axis bracket 24e fixed to the vertical surface of the column 1b by a fixing tool 24f.
A tool support member 24c is supported in the guide member 24a through a ball spline 24b so as to be movable in the X-axis direction.
[0025]
A tool 26 for cutting the outer peripheral surface of the workpiece 16 is detachably attached to the end portion of the tool support member 24c on the workpiece 16 side via a tool attachment member 24d, and on the opposite side of the tool support member 24c. A nut member 27a is fixed to the end, and one end side of a screw shaft 27 made of a ball screw is screwed into the nut member 27a.
The other end side of the screw shaft 27 is connected to an X-axis motor 29 made of a servo motor attached to the column 1b via a bracket 28, and the screw shaft 27 is rotated forward and backward by the X-axis motor 29. As a result, the tool 26 can be moved in the contact / separation direction of the workpiece 16.
[0026]
And, between the X-axis bracket 24e and the Z-axis slide 2, by constraining the vibration on the outer peripheral machining means 24 side and the vibration on the Z-axis slide 2 side, a vibration waveform on the outer peripheral machining means 24 side, A connecting means 30 is provided to make the vibration waveform on the Z-axis slide 2 side substantially the same.
[0027]
As shown in FIGS. 8 and 9, the connecting means 30 has a guide bracket 30a fixed to the distal end side of the X-axis bracket 24e, and guides in a guide hole 30b formed in the guide bracket 30a. The collar 30c is inserted so as to be slidable in the vertical direction.
The upper and lower ends of the guide rod 30c are firmly fixed to a fixing bracket 30e fixed to the Z-axis slide 2 via a fixing tool 30d. Even if the guide rail 1c and the guide rod 30c for guiding the slide 2 are thermally displaced, the vertical movement of the Z-axis slide 2 is not hindered.
[0028]
In addition, 30f in FIG. 9 shows the bellows-like boot which covers so that chips etc. may not adhere to the guide rod 30c.
[0029]
On the other hand, as shown in FIGS. 10 to 12, the inner peripheral processing means 25 for processing the inner peripheral surface of the workpiece 16 is composed of a roller type linear guide laid on the bed 1a in the U-axis direction parallel to the X-axis. A U-axis slide 25 a supported on the guide rail 31 is provided.
The upper part of the U-axis slide 25a is covered with a roof-shaped cover 25c so that chips are easily discharged, and the U-axis slide 25a is placed between the lower part of the U-axis slide 25a and the upper surface of the bed 1a. A U-axis motor 32 composed of a linear servomotor that drives in the direction is installed.
[0030]
The front end side of the U-axis slide 25a reaches the lower part of the lower spindle 11a, and the lower end of a boring bar 25b provided substantially perpendicular to the front end is fixed.
The upper end side of the boring bar 25b reaches the workpiece 16 through the lower spindle 11a, and a tool 33 for cutting the inner periphery of the workpiece 16 is detachably attached to the upper end portion.
[0031]
In FIG. 11, 34 is a U-axis origin detecting means for detecting the origin position of the U-axis slide 25a, and 35 is a slide position detecting means such as a linear scale for detecting the position of the U-axis slide 25a. The detected signal is input to an NC device (not shown) that performs NC control on the Z-axis motor 4, the C-axis motor 19, the X-axis motor 29, the U-axis motor 32, and the like.
[0032]
Next, the operation of machining the workpiece 16 such as a piston ring by the machining apparatus configured as described above will be described.
As shown in FIG. 1A, the workpiece 16 such as a piston ring has different non-circular curved shapes on the outer periphery and the inner periphery, and therefore it is necessary to separately control the outer periphery processing means 24 and the inner periphery processing means 25 by NC control. There is.
[0033]
Since the workpiece 16 is rotated by the C-axis motor 19 and the inner and outer circumferences of the workpiece 16 are simultaneously processed, the X-axis motor 29, the U-axis motor 32, and the Z-axis motor 4 are synchronized with the rotation of the C-axis motor 10. It is necessary to control, and in a normal machining cycle, it takes time to process the movement data, and machining is difficult.
Therefore, in this embodiment, machining is performed by selecting high-speed cycle machining of the NC function or DNC operation.
[0034]
When machining with NC function high-speed cycle machining, register the data converted into the travel per basic processing time and the number of repetitions of that cycle in the NC high-speed machining data area and header section, and use the machining main program. Perform high-speed cycle machining.
In processing, a cylindrical workpiece 16 is formed by laminating a plurality of piston rings with the same phase, and clamped in the vertical direction by a hand carrier jig (not shown), and the processing apparatus main body is kept in that state. 1 and set between the clamp heads 10f and 11f of the upper spindle 10a and the lower spindle 11a.
[0035]
In this state, hydraulic pressure is supplied to the hydraulic chamber 12b of the hydraulic cylinder 12, and the upper spindle 10a is lowered together with the piston 12a. Is clamped so that the center line of the upper and lower spindles 10a and 11a coincides with the center.
[0036]
Next, when the phase of the workpiece 16 is indexed in this state, the upper and lower spindles 10a and 11a are rotated synchronously by the C-axis motor 19 via the C-axis driving means 18, and the workpiece 16 is rotated at, for example, 300 rpm, and the outer periphery machining is performed. The tool 26 provided in the means 24 cuts the outer peripheral surface of the work 16 from, for example, the lower end side of the work 16, and simultaneously cuts the inner peripheral surface of the work 16 from the lower end side by the tool 33 of the inner peripheral processing means 25.
[0037]
Further, since the inner and outer peripheral surfaces of the work 16 are formed by different free curves, the X and Y motors 29 and 32 are separately NC controlled in synchronization with the rotation of the C-axis to control the inner and outer peripheral surfaces of the work 16. While machining, the Z-axis slide 2 is lowered by the Z-axis motor 4 as the machining progresses, and the inner and outer circumferences are cut over the entire length of the workpiece 16.
[0038]
On the other hand, the workpiece 16 has a non-circular shape having a concave portion on the outer peripheral portion, and the tool support member 24c that supports the tool 26 whose speed is zero at the lowest portion of the concave portion is until reaching the highest portion of the concave portion. Although it is suddenly moved in the X-axis direction, a large acceleration is generated at this time, and vibration is generated on the Z-axis slide 2 side that supports the workpiece 16 and the X-axis bracket 24e of the outer peripheral machining means 24 that supports the tool 26. .
[0039]
However, since the Z-axis slide 2 and the X-axis bracket 24e are connected to each other by the connecting means 30 that does not restrict the vertical movement of the Z-axis slide 2, vibration waveforms generated in the Z-axis slide 2 ((( The curve A) in (a) and the vibration waveform generated by the X-axis bracket 24e (curve B in (a) in FIG. 13) are substantially the same, and the displacement difference between both vibration waveforms is very small.
As a result, the machining accuracy of the outer peripheral surface of the workpiece 16 is as shown in FIG. 13 (b), and in particular, the machining accuracy until it is substantially half a circle from the lowest part of the concave portion is as shown in FIG. Compared to a significant improvement.
[0040]
In the above embodiment, the connecting means 30 is composed of the guide rod 30c fixed at both ends to the Z-axis slide 2 side and the guide bracket 30a fixed to the X-axis bracket 24e side. May be.
[Brief description of the drawings]
FIG. 1A is an explanatory diagram of a state in which the outer periphery of a material is processed.
(B) Stroke diagram showing tool movement.
(C) A diagram showing a processing speed.
(D) A diagram showing acceleration generated in the tool support means during machining.
2A is a waveform diagram of vibrations generated in a conventional piston ring processing machine. FIG.
(B) It is explanatory drawing which shows the process surface of the workpiece | work processed with the conventional piston ring processing machine.
FIG. 3 is a front view of the piston ring processing apparatus according to the embodiment of the present invention.
FIG. 4 is a side view of the piston ring processing apparatus according to the embodiment of the present invention.
FIG. 5 is an enlarged view of a main part of the piston ring processing apparatus according to the embodiment of the present invention.
FIG. 6 is a cross-sectional view of the C-axis and Z-axis driving means of the piston ring machining apparatus according to the embodiment of the present invention.
FIG. 7 is a cross-sectional view of the workpiece support means of the piston ring machining apparatus according to the embodiment of the present invention.
FIG. 8 is a cross-sectional view of the outer periphery processing means of the piston ring processing apparatus according to the embodiment of the present invention.
FIG. 9 is a front view of the outer periphery processing means of the piston ring processing apparatus according to the embodiment of the present invention.
FIG. 10 is a plan view of the inner periphery machining means of the machining apparatus according to the embodiment of the present invention.
FIG. 11 is a side view of the inner periphery machining means of the machining apparatus according to the embodiment of the present invention.
12 is an arrow view from the direction D in FIG. 11;
13A is a waveform diagram of vibrations generated in the piston ring processing machine according to the embodiment of the present invention. FIG.
(B) It is explanatory drawing which shows the process surface of the workpiece | work processed with the piston ring processing machine which becomes embodiment of this invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Processing apparatus main body 1a ... Bed 1b ... Column 1c ... Guide rail 2 ... Z-axis slide 3 ... Z-axis drive means 4 ... Z-axis motor 4a ... Rotating shaft 5 ... Screw shaft 5a ... Nut member 6 ... Strip 7 ... Pulley 8 ... Counterweight 10 ... Upper work 10a ... Upper spindle 10b ... Ring 10c ... Fixed shaft 10d ... Spring seat 10e ... Compression spring 10f ... Upper clamp head 11 ... Lower work support means 11a ... Lower spindle 11f ... Lower clamp head 11g ... Plate DESCRIPTION OF SYMBOLS 12 ... Hydraulic cylinder 12a ... Piston 13 ... Bearing 14 ... Thrust bearing 16 ... Workpiece 18 ... C-axis drive means 18a ... Gear train 18b ... Driven gear 18c ... Drive shaft 18d ... Drive gear 18e ... Intermediate gear 19 ... C-axis motor 20 ... Reducer 20a ... Input shaft 20b ... Fly wheel 20c ... Output shaft 22 ... Thrust bearing 24 ... Peripheral machining means 24a ... guide member 24b ... ball spline 24c ... tool support member 24d ... tool mounting member 24e ... X-axis bracket 25 ... inner surface machining means 25a ... U-axis slide 25b ... boring bar 25c ... cover 27 ... screw shaft 27a ... nut Member 28 ... Bracket 29 ... X-axis motor 30 ... Connecting means 30a ... Guide bracket 30b ... Guide hole 30c ... Guide rod 30d ... Fixing tool 30e ... Fixed bracket 30f ... Boot 31 ... Guide rail 32 ... U-axis motor 33 ... Tool 34 ... U-axis origin detection means 35 ... slide position detection means

Claims (3)

In the piston ring processing apparatus for processing the inner and outer peripheral surfaces of the work 16 in which the inner and outer peripheral surfaces are formed by non-circular curves,
A Z-axis slide 2 which is movable in the vertical direction (Z-axis direction) by the Z-axis drive means 3 and is provided with an upper work support means 10 and a lower work support means 11 apart from each other in the vertical direction ;
A C-axis driving unit 18 for rotating the workpiece 16 via the workpiece support means 10, 11,
An outer periphery processing means 24 provided on an X-axis bracket 24e, which is capable of moving a tool 26 for processing the outer peripheral surface of the workpiece 16 in an X-axis direction perpendicular to the axis of the workpiece 16;
A connection that connects the Z-axis slide 2 and the X-axis bracket 24e so as not to restrict the movement of the Z-axis slide 2 in the Z-axis direction and to restrict the movement in the direction perpendicular to the Z-axis direction. Means 30 and
Piston ring machining apparatus characterized by comprising a. The connecting means 30, provided parallel to the Z axis and two ends and a guide lever 30e which is fixed to the Z-axis slide 2, is slidably inserted in the guide rod 30e, and the X-axis bracket 24e The piston ring processing device according to claim 1, comprising a guide bracket 30 a fixed to the guide bracket. The connecting means 30, piston ring machining system for a linear arrangement the guide rail and formed by claim 1, wherein provided between the Z-axis slide 2 and the X-axis bracket 24e.

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