JP2010214498A - Inner surface grinding tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tool improving machining efficiency by simultaneously machining a plurality of regions to be worked when grinding their inner surfaces, and assuring machining accuracy of all worked regions. <P>SOLUTION: In an inner surface grinding tool 1 coaxially including a plurality of machining units 3, each machining unit 3 is equipped with: an external threaded member 13 rotatable by a servo motor 12 with a decelerator; and an internal threaded cylinder 14 advancing and retreating by rotation of the external threaded member 13. Slope grooves 16 axially inclined are provided symmetrically at an upper part and a lower part of the internal threaded cylinder 14. Engaging parts 18 of a pair of cutting tools 17 are engaged with the respective slope grooves 16, whereby the pair of cutting tools 17 radially expand and contract by advance/retreat of the internal threaded cylinder 14. Thus, the respective servo motors 12 with the decelerator are individually driven by remote control. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an internal grinding tool suitable for precision machining of a plurality of journal bearings of an engine, for example.

Conventionally, when grinding the inner surface of a workpiece, the cam member that expands the grindstone is used as an expansion screw when performing individual machining such as engine cylinder bores, etc. A technique (for example, refer to Patent Document 1) is known in which the blade diameter is controlled by screw feed driving with a scissors.
Further, for example, when processing a journal bearing portion that receives the crankshaft of an engine, an internal grinding tool for simultaneous multiple processing that simultaneously processes a plurality of processing portions may be used.

JP-A-6-190713

  However, in the conventional technique, there is no technique for individually controlling the blade diameter in the internal grinding tool for simultaneous multiple machining that simultaneously processes a plurality of holes. For example, when the diameter is uniformly controlled, There have been problems such as variations in diameter accuracy due to differences in rigidity, the effect of variations in the initial sharpness of the cutting tool, and the degree of progress of wear. Also, when processing journal bearings etc. for simultaneous multiple machining that does not have a general expansion / contraction mechanism, when the tool is inserted into or ejected from the center hole of the workpiece, it will be damaged by interference with the finished surface. In order to prevent this, since insertion and ejection are performed with the arbor center offset with respect to the work center, only one tool can be attached to each journal bearing portion, resulting in a problem of poor machining efficiency.

  Furthermore, the simultaneous machining of the journal bearing part increases the overall length of the processing part, which inevitably increases the overall length of the arbor, and with conventional tools, the cutting tool is laid out at a position facing the central axis of the arbor. Because it was difficult to do, balance processing was not possible. For this reason, the arbor receives a plurality of machining loads from one direction at the same time, and the arbor easily deforms due to the machining load, and there is a problem in that it is difficult to obtain the targeted accuracy.

  Therefore, the present invention provides a tool capable of improving machining efficiency by machining a plurality of machining parts such as journal bearing parts of a multi-cylinder engine at the same time, and at the same time guaranteeing machining accuracy of all the bearing parts. The purpose is to provide.

  In order to achieve the above object, the present invention provides an internal grinding tool having a plurality of machining units for simultaneously machining the inner surfaces of a plurality of locations of a workpiece. Can be scaled individually.

In this way, if the inner diameter of each cutting tool can be individually expanded / reduced, for example, when processing the journal bearing portion, the procedure of inserting / discharging the cutting tool with the inner diameter reduced is taken. This eliminates the need to insert and eject the center axis of the arbor by offsetting the center axis of the arbor as before, eliminating the need to insert and eject as before, and the degree of wear of the cutting tool In addition, if the inner diameter of each cutting tool is individually controlled in accordance with the rigidity of the processed part of the workpiece, variations in diameter accuracy can be prevented.

In the present invention, as the expansion / contraction mechanism, a female screw member that can be moved forward and backward by the rotation of the male screw member and an engaging portion of the blade that engages the slope portion of the female screw member are provided, and the inner diameter of the blade tool is increased by the rotation of the male screw member. It became possible to expand and contract freely.
At this time, two or more blades are provided at a uniform angle in the circumferential direction of the tool shaft in each processing unit, and each expansion / contraction mechanism is provided with a motor as a power source for rotating the male screw member for each processing unit. It is preferable that each motor is individually controlled by the control unit.

  By adopting such a structure, it is easy to arrange similar structures in series, and it can be compactly packed in the axial direction, and does not require a spring or an elastic body for the expansion / contraction mechanism. Are arranged symmetrically with respect to the central axis of the arbor, the rotation balance is good, and high-speed rotation is possible and the machining efficiency is improved. As a result, the processing accuracy is also improved.

In an internal grinding tool equipped with multiple machining units, the inner and outer diameters of each cutting tool can be individually expanded and contracted by the expansion and contraction mechanism of each processing unit, thereby simplifying the procedure for inserting and ejecting the workpiece into the processing hole. At the same time, the inner diameter of each cutting tool can be individually controlled according to the state of each cutting tool, and variations in diameter accuracy can be prevented.
In addition, as the structure of the expansion / contraction mechanism, a rotatable male screw member or a female screw member having a slope portion is provided so that the inner diameter of the cutting tool can be expanded / contracted by the rotation of the male screw member, and the cutting tool of the processing unit is attached to the tool shaft. If two or more blades are provided at equal angles in the circumferential direction, and each expansion / contraction mechanism is provided with a motor as a power source for the rotation of the male screw member for each processing unit, similar structures are arranged in series. It is easy, and it can be packed compactly in the axial direction and well balanced in the rotational direction. As a result, it is easy to improve the rotation balance, and the processing efficiency and processing accuracy are improved.

External view of internal grinding tool with 5 sets of machining units Explanatory drawing for explaining the enlargement / reduction mechanism of the machining unit Vertical section of processing unit FIG. 4 is an operation diagram of the expansion / contraction mechanism, where (a) is a state diagram in which the cutting tool diameter is reduced, and (b) is a state diagram in which the cutting tool diameter is expanded. Operation diagram of the entire internal grinding tool, (a) is a state diagram during standby, (b) is a state diagram during machining Explanatory drawing of the entire grinding machine to which the internal grinding tool is mounted Explanatory drawing of the state which processes five journal bearing parts of a 4-cylinder engine

Embodiments of the present invention will be described with reference to the accompanying drawings.
Here, FIG. 1 is an external view of an internal grinding tool provided with five sets of machining units, FIG. 2 is an explanatory diagram for explaining an enlargement / reduction mechanism of the machining unit, FIG. 3 is a longitudinal sectional view of the machining unit portion, and FIG. (A) is a state diagram in which the cutting tool diameter is reduced, (b) is a state diagram in which the cutting tool diameter is expanded, FIG. 5 is an operation diagram of the entire internal grinding tool, and (a) is a state diagram during standby. (B) is a state diagram at the time of processing, FIG. 6 is an explanatory diagram of the entire grinding apparatus to which the internal grinding tool is mounted, and FIG. 7 is an explanatory diagram of a state in which five journal bearing portions of a four-cylinder engine are processed. .

  The internal grinding tool according to the present invention can efficiently process a plurality of processing parts such as a journal bearing part of a multi-cylinder engine at the same time in each processing unit, and the processing accuracy of all the bearing parts. It is configured as a tool that improves the quality, and is characterized in that the expansion and contraction of each cutting tool of a plurality of processing units can be controlled separately.

That is, the internal grinding tool 1 as an arbor includes five sets of coaxial processing units 3 incorporated in a cylindrical case 2 as shown in FIGS. 1 to 3, for example, as shown in FIG. In a four-cylinder engine composed of a simple cylinder block W ₁ and a lower block W _2, it is possible to simultaneously process five semicircular journal bearing portions j in a state where the cylinder block W ₁ and the lower block W ₂ are fastened. Has been.

  As shown in FIG. 6, the outline of the configuration of the entire grinding apparatus to which the present internal grinding tool 1 is applied is shown in FIG. 6 for the spindle motor 4 for rotationally driving the internal grinding tool 1 in grinding and the cutting tools of the machining unit 3. A control unit 5 for controlling expansion / contraction is provided. The control unit 5 includes an NC controller 7, a control unit 6 for individually controlling the expansion diameters of the five blades, and a motor 12 of the machining unit 3 described later. Are provided with a non-contact power supply unit 8 and a non-contact communication unit 9 for individually controlling non-contact driving.

  The control unit 5 controls only the motor 12 of the processing unit 3 when adjusting the extension amount of the cutting tool of the processing unit 3 individually in order to align the machining finish dimensions, etc. At the time of inserting / discharging 1 or cutting, all the motors 12 of all the processing units 3 are controlled simultaneously.

  As shown in FIGS. 2 and 3, the processing unit 3 includes a servo motor 12 with a speed reducer held by a motor bracket 11 fixed to the inner surface side of the case 2, and a male screw member that is rotationally driven by the motor 12. 13 and a female screw cylinder 14 as a female screw member that meshes with the screw portion of the male screw member 13 and can be moved forward and backward in the axial direction by the rotation of the male screw member 13. A window 15 through which the bracket 11 can be inserted is formed long in the axial direction, and a dovetail groove as a slope portion that engages with an engaging portion 18 of a blade 17 described below at the upper and lower portions of the female screw cylinder 14. The slope groove portion 16 of the mold is formed in a vertically symmetrical position. In the present embodiment, the slope of the slope groove is inclined slightly lower from the left to the right as shown in FIG.

The cutting tool 17 is assembled integrally with the cutting tool holder 20 so as to be slidable up and down with respect to the cutting tool holder 20, and an Arihozo type engaging portion 18 provided integrally inside the cutting tool 17 is provided. As described above, it is fitted into the dovetail-shaped slope groove portion 16 and engaged therewith. In addition, a grinding wheel is attached to the top surface of the blade 17, and such a blade 17 is disposed in the upper and lower slope grooves 16 of the female screw cylinder 14.
In the present embodiment, a pair of the slope groove portion 16 and the cutting tool 17 are provided at symmetrical positions around the tool axis, but two or more blades may be provided at equal angles in the circumferential direction of the tool axis.
Therefore, in this embodiment, as shown in FIG. 4A, when the female screw cylinder 14 is moved to the left in the drawing by the rotation of the motor 12, the engaging portion 18 that engages the slope groove portion 16 having a low inclination is used. When the pair of upper and lower cutting tools 17 is reduced toward the inside in the radial direction and the female thread cylinder 14 is moved to the right in the drawing as shown in FIG. 4B, the pair of upper and lower cutting tools 17 are directed toward the outside in the radial direction. Has been extended. That is, the expansion / contraction mechanism is constituted by the male screw member 13, the female screw cylinder 14, the slope groove portion 16, the engaging portion 18, and the like.

  A spring 21 for absorbing backlash between the slope groove portion 16 and the engaging portion 18 is provided between the blade holder 20 and the blade 17.

In the internal grinding tool 1 as described above, when machining the journal bearing part of the four-cylinder engine as shown in FIG. 7, the cutting tool 17 of each machining unit 3 of the grinding tool 1 is fully retracted and stored (see FIG. in 5 (a)), inserted into the journal bearing portion j is formed by the fastening of the cylinder block W ₁ and lower block W _2.

  When the insertion is completed, all the cutting tools 17 are driven by driving all the motors 12 with speed reducers by the signals from the control unit 5 to rotate the male screw members 13 of all the processing units 3 and retreating the female screw cylinders 14. Is extended outwardly in the radial direction (FIG. 5B). At this time, since the windows 15 on both the left and right sides of the female screw cylinder 14 are opened with an axial length sufficient to absorb this slide stroke, the female screw cylinder 14 interferes with the motor bracket 11. There is no.

  Then, the spindle motor 4 is driven to perform cutting, but each processing unit 3 can perform balance processing because of the symmetrical tool 17, and the internal grinding tool 1 can be flexibly reduced due to processing load and rotated. Since the balance is not easily distorted, high-speed rotation is possible, and as a result, machining time can be shortened.

  In addition, when the finished diameter changes due to tool wear, variation in rigidity of the workpiece processing part, etc., the amount of expansion of the blade 17 of the individual processing unit 3 can be controlled. The finished diameter can be made uniform, for example, by combining the function of measuring the finished diameter after expansion and feeding back to the individual target expanded diameter.

  When the machining is completed, all the motors 12 with speed reducers are driven by signals from the control unit 5 to rotate the male screw member 13 and advance the female screw cylinder 14 to slide each blade 17 inward in the radial direction. In the contracted state (FIG. 5A), the workpiece is discharged.

  According to the above procedure, variation in the diameter accuracy of the plurality of machining holes can be suppressed, and the work efficiency is extremely good because the work is efficiently inserted and ejected.

In addition, this invention is not limited to the above embodiments. What has the same practical configuration as the matters described in the claims of the present invention and exhibits the same operational effects belongs to the technical scope of the present invention.
For example, the type of workpiece is an example.

  When machining the inner surface of multiple parts of a workpiece simultaneously with multiple cutting tools, the extended diameter of each cutting tool can be individually controlled, so that the finishing accuracy can be made uniform and the work can be performed efficiently. For example, the journal bearing part of an engine It is extremely effective for the processing.

DESCRIPTION OF SYMBOLS 1 ... Internal grinding tool, 3 ... Processing unit, 5 ... Control unit, 12 ... Motor with speed reducer, 13 ... Male screw member, 14 ... Female screw cylinder, 16 ... Slope groove part, 17 ... Cutting tool, 18 ... Engagement part.

Claims (4)

An internal grinding tool provided with a plurality of machining units for simultaneously machining the inner surfaces of a plurality of locations of a workpiece, wherein each of the machining units has an inner diameter of each cutting tool individually expandable / reducible by a respective expansion / contraction mechanism. An internal grinding tool characterized by that. The expansion / contraction mechanism includes a female screw member that is movable back and forth by the rotation of the male screw member, and an engagement portion of the blade that engages with the slope portion of the female screw member, and the inner diameter of the blade tool can be expanded and contracted by the rotation of the male screw member. The internal grinding tool according to claim 1. The internal grinding tool according to claim 2, wherein the cutting tool of the processing unit is provided with two or more blades at an equal angle in a circumferential direction of the tool shaft. The said expansion / contraction mechanism is provided with the motor used as the motive power source of the rotation of the said male screw member for every process unit, and each motor is individually controllable by the control unit. 3. An internal grinding tool according to 3.