JPH0775905A - Cutting tool - Google Patents

Abstract

PURPOSE:To easily recover machining precision by mounting a coupling member, engaged with a slider to be slidden, inside a tool mainframe. CONSTITUTION:A tool mainframe 11 being rotated around an axial line O is given feeding toward the axial line O to form chamfers on the inner and outer peripheries of an opening in a valve hole with cutting edge tips 5A, 5B fixed to the tool mainframe 11. The tool mainframe 11 is somewhat moved backward as it is rotated and then a slide shaft is extruded to move forward a coupling member 8, so that a slider 16 is slided along a generating line to slide a cutting edge tip 5C and a tapered face is formed between the chamfers formed on the inner and outer peripheries of the opening in the valve hole. A hole making tool is moved forward and inserted into the valve hole to finish the valve hole itself. Cutting load applied to the cutting edge tip 5C during forming the tapered face is accepted by a cartridge via the slider 16.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool most suitable for machining valve holes in a cylinder head of an engine.

[0002]

2. Description of the Related Art In such a valve hole of a cylinder head, since the valve frequently hits the periphery of the opening of the hole, a hard member such as a sintered alloy is fitted to this portion for durability. I am trying to get it. Therefore, as a cutting tool for processing the valve hole, a tool including a hole processing tool such as a gun reamer for finishing the hole itself and a cutting edge tip for processing the peripheral edge of the opening is used. Moreover, the opening is often formed in a tapered surface shape in accordance with the shape of the valve head, so that the cutting edge tip is attached to the rotation axis of the cutting tool so that cutting of such a surface is possible. It is desirable that it be slidably mounted in a diagonal direction.

FIGS. 7 to 10 show an example of a conventional cutting tool used for machining such a valve hole. In these figures, the tool main body 1 has a substantially conical shape, is attached to a spindle end of a machine tool or the like via an adapter (not shown), is rotated around its axis O, and is used for cutting. Further, the axis O is attached to the tip of the tool body 1.
Bush 2 is installed along the
By inserting the shank of a hole drilling tool (not shown) such as the above-mentioned gun reamer and advancing the hole drilling tool while rotating together with the tool body 1, it is possible to finish the hole itself. The advance of the hole drilling tool is performed by a shaft 4 coaxially inserted into a slide shaft 3 described later. Furthermore, three cutting edge chips 5 ... Are provided on the outer periphery of the tip of the tool body 1,
The peripheral edges of the opening of the valve hole are processed by these cutting blade tips 5.

Here, among these cutting edge chips 5, ...
The two cutting blade tips 5A and 5B are directly fixed to the tool body 1, while the remaining one cutting blade tip 5C is slidably mounted as described above. That is, as shown in FIG. 10B, the T-groove 6 is formed in the tool body 1 along the direction of the generatrix of the conical shape of the tool body 1, that is, in the direction oblique to the axis O. A slider 7 is slidably fitted in the groove 6 and the cutting edge tip 5 is inserted.
C is detachably fixed to the slider 7. On the other hand, a charging hole 1a is formed inside the tool body 1 along the axis O, and the coupling member 8 attached to the tip of the slide shaft 3 is inserted into the charging hole 1a. ing. The coupling member 8 is fitted into the charging hole 1a via a key 9, so that the tool body 1 and the coupling member 8 can rotate integrally around the axis O and the slide shaft 3 can be rotated. By moving back and forth, the charging hole 1a can be moved back and forth.

Further, the T groove 6 of the tool body 1 and the charging hole 1a are communicated with each other through an elongated hole 6a which is opened at the bottom surface of the T groove 6. A connecting pin 10 is attached to the slider 7 so as to project into the charging hole 1a through the elongated hole 6a, and the tip of the connecting pin 10 is attached to the coupling member 8.
The slider 7 and the coupling member 8 are connected by being inserted into the oblique hole 8a formed in the. Then, by moving the coupling member 8 forward and backward through the slide shaft 3, the slider 7 slides along the T groove 6 so that the cutting blade tip 5C slides in a direction oblique to the axis O. There is.

In order to perform the above-described valve hole machining with the cutting tool having such a construction, a hole machining tool such as a gun reamer is attached to the bush 2 and the bush 4 is pulled toward the base end side of the tool body 1. Then, the tool body 1 is rotated on that, and the feed is given in the direction of the axis O. First, the opening portion of the valve hole is chamfered by the two cutting blade tips 5A and 5B. Then, the tool body 1 is slightly retracted, and then the coupling member 8 is advanced by the slide shaft 3 while rotating the tool body 1, and the cutting blade tip 5C is slid through the connecting pin 10 and the slider 7. Thus, the tapered surface as described above is formed on the periphery of the opening of the valve hole. Thereafter, the hole machining tool is advanced by the shaft 4 while the tool body 1 is rotated, and the inside of the valve hole (valve guide hole) is finished.

[0007]

By the way, in the cutting tool having the above construction, when the tapered surface is formed at the peripheral edge of the opening portion of the valve hole as described above, the cutting load acting on the cutting edge tip 5C is applied to the slider 7 Since it is received by the wall surface of the T-groove 6 of the tool body 1 (especially the wall surface facing the tool rotation direction) through the tool, the wall surface of the T-groove 6 is worn or worn by such a cutting load during long-term use. Deformation will occur. Further, the wall surface is worn even when the slider 7 slides in the T groove 6. Then, such wear causes rattling of the slider 7, which may impair the processing accuracy of the cutting blade tip 5C. Specifically, the slider 7 does not slide straight, and the restraining force from the main body is lost at the worn portion to cause rattling or vibration, and the tapered surface does not become an accurate conical surface. In addition, the life of the cutting edge will be shortened.

When such wear occurs in the cutting tool having the above construction, the T groove 6 is widened and corrected by polishing or the like to form a new wall surface and the new T groove 6 is formed. By remanufacturing the slider 7 having the size and shape according to the above, the tool body 1 and the like are reused. However, if such measures are taken,
Since it is necessary to correct the T-groove 6 and re-manufacture the slider 7 each time wear occurs, it is inevitable that the work becomes complicated, and the size and shape of the slider 7 change every time it is re-manufactured. You will have to redesign it as well. Therefore, reusing the tool body 1 may result in an uneconomical situation.

Further, in the cutting tool having the above structure, the slider 7 is inserted into the T-groove 6, and the slider 7 has a sliding direction due to the seven surfaces of the T-groove 6 having a "convex" cross section. However, it is not easy to process and shape all seven surfaces with high accuracy, and high processing accuracy is required. The accuracy of the surface of
From there, wear progresses at a stretch, which promotes rattling of the slider 7 and shortens the tool life. Furthermore, in the T-groove 6 having such a “convex” cross-section, the intersection line between the seven surfaces is
It is necessary to provide a recess (seed) for avoiding interference with the slider 7, but this allows the slider 7 and the T
A slight gap is created between the groove 6 and the groove 6. There is also a problem that wear is further promoted by the intrusion of fine chips and the like generated during cutting into this gap.

[0010]

The present invention has been made to solve the above problems, and the cutting tool according to claim 1 has a substantially conical tool body rotated about an axis. A concave groove is formed along the conical generatrix, and a cartridge having a mounting hole extending along the direction of the generatrix is detachably mounted in the concave groove, and a cutting blade tip is attached to the tip of the mounting hole. The slider provided is slidably mounted along the direction of the generatrix and fitted so that the rotation around the generatrix is constrained, and inside the tool body is rotatable integrally with the tool body, and It is characterized in that a coupling member is provided which is movable back and forth along the axis and which engages with the slider and slides the slider.

A cutting tool according to a second aspect of the present invention is the cutting tool according to the first aspect, wherein the mounting hole includes a first hole portion having a circular cross section having a central axis parallel to the generatrix, and the first hole portion. Second circular cross section having a central axis parallel and eccentric to the central axis
And a portion which is inserted into the mounting hole of the slider is formed in an eccentric multi-stage cylindrical shape that is in close contact with the inner circumferences of the first hole portion and the second hole portion. To do. Furthermore, the cutting tool according to claim 3 is the cutting tool according to claim 1.
Alternatively, in the cutting tool of No. 2, the cartridge is provided with a preload mechanism for pressing a portion fitted into the mounting hole of the slider against an inner peripheral surface of the mounting hole.

[0012]

In the cutting tool having the above construction, since the slider is slidably mounted in the groove through the cartridge, the cutting load and the abrasion due to the sliding of the slider do not directly occur in the tool body. Will occur in. Therefore, it is possible to easily restore the processing accuracy of the cutting edge tip mounted on the slider simply by replacing the cartridge. Further, by forming the mounting hole of this cartridge from the first hole portion and the second hole portion having a circular cross section as described above, and forming the slider into a multi-stage cylindrical shape, the mounting hole and the slider can be easily and highly molded. In addition to the accuracy, the slider can be prevented from rattling by firmly pressing the rotation of the slider due to the cutting load and the like. Further, since the columnar slider is fitted into the hole having a circular cross section, it is not necessary to provide a hollow as in the conventional case, and it is possible to prevent chips or the like from being caught. Furthermore, by providing the cartridge with the preload mechanism, the slider can be more firmly held in the cartridge, and the occurrence of rattling can be prevented more effectively.

[0013]

1 to 6 show an embodiment of the present invention. Since this embodiment is similar in basic structure to the conventional cutting tool shown in FIGS. 7 to 10,
The common parts are given the same reference numerals to simplify the description. The slide shaft 3 is not shown in these figures. In this embodiment, instead of the T-groove 6 formed in the tool body 1 of the conventional cutting tool, a cross section as shown in FIGS. 4 and 5 is formed on the conical tool body 11 along the direction of its generatrix. The rectangular groove 12 is formed,
A cartridge 13 having a substantially rectangular parallelepiped outer shape is detachably mounted in the groove 12 with a fixing screw 14. Then, in the cartridge 13, the cartridge 13
In the mounted state, the mounting hole 15 is arranged so as to be along the bus line direction.
And a slider 16 having a cutting edge tip 5C at its tip is fitted and inserted into the mounting hole 15.

Here, the mounting hole 15 is formed in the tool main body 11
The first hole portion 15A located on the inner peripheral side and the second hole portion 15B located on the outer peripheral side. These first and second hole portions 15A and 15B are each formed in a circular shape with their respective cross-sections having center axes C1 and C2 parallel to the generatrix, and the inner diameter of the first hole portion 15A is larger than that of the first hole portion 15A. It is larger than the second hole portion 15B, and the length in the generatrix direction is the second
The hole 15B is set to be longer than the first hole 15A. And these 1st and 2nd hole part 1
In 5A and 15B, the central axis C ₂ of the second hole is the inner peripheral side and the base end side of the tool body 11 (the upper right side in FIG. 1, FIG. 4 and FIG. 5) with respect to the central axis C ₁ of the first hole. In the bottom),
That is, it is formed so as to be eccentric so as to be located on the bottom surface 12A side of the concave groove 12, whereby the tool body 1 on the inner peripheral surface of each of the first and second hole portions 15A and 15B.
The inner peripheral side portion and the base end side portion of 1 are set to be substantially flush with each other.

On the other hand, according to the structure of the mounting hole 15 as described above, the portion of the slider 16 which is fitted into the mounting hole 15 is a first cylindrical portion 16A which is fitted into the first hole portion 15A.
And a second columnar portion 16B fitted and inserted into the second hole portion 15B, and is formed in a multi-stage columnar shape.
The second cylindrical portions 16A and 16B are formed such that the central axes thereof are eccentric according to the eccentric amounts of the central axes C ₁ and C ₂ . By inserting the slider 16 into the mounting hole 15 of the cartridge 13, the slider 16 can be rotated about the central axis C ₁ in the second hole portion 15B.
When the second is restrained by the engagement between the cylindrical portion 16B, the central axis C ₂ around the pivot in the opposite first hole 15A and the first cylindrical portion 16
Since the slider 16 is constrained by the fitting with A, the rotation of the slider 16 around the bus bar is constrained as a result, and only the sliding along the direction of the bus bar is allowed.

Between the first and second cylindrical portions 16A and 16B of the slider 16 and the first and second hole portions 15A and 15B of the mounting hole 15, thin-walled cylindrical bushes 17 and 17 are provided, respectively. Is installed. Therefore, the first
The outer diameters of the second columnar portions 16A and 16B are set so that the outer peripheral surfaces thereof are in close contact with the inner peripheral surfaces of the first and second hole portions 15A and 15B with the bush 17 interposed therebetween. Further, the side surface 13A of the cartridge 13 that faces the tip end side of the tool body 11 when mounted on the tool body 11
At the four corners of the tightening screw 18 ...
Is screwed on. The tips of the tightening screws 18 are brought into contact with the outer peripheral surfaces of the bushes 17, 17, and the first and second cylindrical portions 16A of the slider 16 are tightened by tightening the tightening screws 18. ，
16B is pressed against the inner peripheral portion of the tool body 11 of the mounting hole 15 via the bushes 17, 17.
That is, in this embodiment, the preload mechanism is constituted by these tightening screws 18 ...

Further, the side surface 1 is provided on the cartridge 13.
An insertion hole 13C that penetrates from 3A toward the side surface 13B located on the bottom surface 12A side of the concave groove 12 in the mounted state of the cartridge 13 and communicates with the mounting hole 15 is formed. On the other hand, the second cylindrical portion 16B of the slider 16 is formed with an elongated hole 16C penetrating in the diametrical direction thereof and extending in the central axis C ₂ direction. The elongated hole 16C fits the slider 16 into the cartridge 13. It is set so as to communicate with the insertion hole 13C in the inserted state. The fixing screw 14 is screwed to the tool body 11 through the insertion hole 13C and the elongated hole 16C, whereby the slider 16 is slidable and the cartridge 1 is inserted.
3 is fixed to the tool body 11.

Further, the second cylindrical portion 16 of the slider 16
A fitting hole 16D is formed in B in a direction orthogonal to the central axis C ₂ thereof and obliquely intersecting the axis O of the tool body 11 toward the inner peripheral side and the base end side of the tool body 11. . The side surface 13B of the cartridge 13 is provided with the fitting hole 16D.
The elongated hole 13D is formed so as to face the concave groove 1D.
2 is communicated with an elongated hole 6a of a tool main body 11 which connects the insertion hole 1a into which the coupling member 8 is inserted.
Then, these elongated holes 13D, 6 are provided in the fitting hole 16D.
the connecting pin 10 so as to project into the charging hole 1a through a.
Is inserted, and the connecting pin 10 is inserted into the oblique hole 8a of the coupling member 8 so that the slider 1
6 and the coupling member 8 are connected. A screw 19 for fixing the fitted connecting pin 10 is tightened from the rear end of the slider 16.

The cutting tool having such a structure is also applicable to the tool body 1
A bushing tool such as a gun reamer is attached to the bush 2 at the tip of the tool 1, and the bushing 2 is attached to the spindle end of a machine tool through an adapter or the like, and is used for cutting around the valve hole and its opening. That is, first, with the hole drilling tool pulled in toward the base end side, the tool body 11 is rotated around its axis O while being fed in the direction of the axis O, so that the cutting edge tip 5A fixed to the tool body 11, 5B forms chamfers on the inner peripheral side and the outer peripheral side of the opening of the valve hole. And
After the chamfer is formed in this way, the tool body 11 is slightly retracted while the tool body 11 is being rotated, and then a slide shaft (not shown) is projected to cause the coupling member 8 to rotate.
By moving the slider 16 in the generatrix direction through the connecting pin 10 to slide the cutting blade tip 5C, and between the chamfer formed on the inner peripheral side and the outer peripheral side of the opening of the valve hole. Form a tapered surface. Then, while the tool body 11 is still rotating, the hole machining tool such as the gun reamer is advanced by the shaft in the slide shaft and inserted into the valve hole, and the valve hole itself is finished.

In the cutting tool having the above construction, however, the cutting load acting on the cutting edge tip 5C when forming the tapered surface is received by the cartridge 13 via the slider 16. Therefore, the cutting load causes wear and deformation in the cartridge 13, and the concave groove 12, that is, the tool body 11 is not worn or deformed. Further, wear caused by sliding the slider 16 does not occur in the cartridge 13 and damages the tool body 11. Since this cartridge 13 is detachably attached to the tool body 11 with one fixing screw 14,
When wear or deformation occurs, it can be replaced with a new one, so that the machining accuracy and the like can be recovered very easily. Moreover, it is sufficient to replace the member with the same standard as the member before replacement, and it is not necessary to redesign the member each time abrasion occurs, which is extremely economical. This also applies when replacing the slider 16.

Further, the slider 16 and the cartridge 13
The parts that come into close contact with the mounting holes 15 of the first and second cylindrical parts 16A and 16B and the first and second hole parts 15 respectively.
It is composed of A and 15B, and both are formed to have a circular cross section. Therefore, compared to the conventional cutting tool that inserts a slider into a T-shaped groove with a "convex" cross section. Molding is easy, and high molding accuracy can be obtained. Further, in the slider 13, the outer peripheral surfaces of the first and second columnar portions 16A and 16B and the inner peripheral surfaces of the first and second hole portions 15A and 15B of the mounting hole 15 are in close contact with each other, whereby the cartridge Since the slider 16 is firmly held, the rattling of the slider 16 can be reliably prevented by suppressing the rotation of the slider 16 due to the cutting load, and the machining accuracy can be further improved.

Furthermore, the first and second columnar portions 15A and 15B of the slider 16 are the first and second hole portions 15A and 15B of the circular cross section of the mounting hole 15 of the cartridge 13.
Since the cartridge 13 is fitted into the mounting hole 15 and is attached to the mounting hole 15, it is not necessary to provide a slack in the mounting hole 15 side or the like.
There is no gap between the cartridge 5 and the cartridge 13. For this reason, it becomes possible to prolong the life of the tool without the fine chips being caught in such a gap to promote wear. In addition to this, in the present embodiment, the first and second cylindrical portions 15 of the slider 16 are
A, 15B and the first and second hole portions 15A of the mounting hole 15,
Since the bushes 17 and 17 are interposed between the bushes 15B and 15B, it is possible to more reliably prevent the cutting chips and the like from being caught.

On the other hand, in this embodiment, the cartridge 13 is provided with the tightening screws 18 as a preloading mechanism, and by tightening these tightening screws 18, the slider 16 is pressed through the bushes 17, 17. Then, it is pressed against the inner peripheral surface of the mounting hole 15. Therefore, according to the present embodiment, the slider 16 can be more firmly held in the cartridge 13, and in combination with the above effect, rattling of the slider 13 can be prevented more reliably, and higher processing accuracy can be achieved. Can be obtained. In this embodiment, the tightening screw 1 is used as the preload mechanism in this way.
8 is used, but the slider 16 may be pressed by a disc spring or the like as long as the slider 16 can be pressed against the inner peripheral surface of the mounting hole 15.

Further, in this embodiment, the mounting hole 15 of the cartridge 13 is eccentric, and the first and second hole portions 15 having a circular cross section are provided.
The first and second parts are formed by A and 15B and are eccentric to the slider 16 fitted in the mounting hole 15.
The sliders 16 are slidable in the generatrix direction of the tool body 11 and their rotations are restrained by forming the cylindrical portions 16A and 16B, and the slider 16 is inserted via the cartridge 13 into the tool body. If it is attached to 11, it is not always necessary to adopt such a configuration.
For example, the cross section of the mounting hole may be formed in a polygonal shape such as a regular hexagon, and the cross section of the slider may be shaped to fit into this. Further, the mounting hole and the slider may have a circular cross section, and a key may be fitted between them to restrain rotation of the slider. Furthermore, if the mounting hole and the slider are formed to have elliptical or elliptical cross sections, the slider can be reliably restrained from rotating while maintaining the ease of molding as in the above embodiment.

[0025]

As described above, according to the present invention, the cutting load acting from the cutting edge tip through the slider and the wear and deformation due to sliding of the slider are interposed between the slider and the tool body. This occurs in the cartridge, and the machining accuracy can be easily restored by replacing the cartridge, and the standard of this cartridge does not change each time the cartridge is replaced, which is economical. Further, by forming the mounting hole of the cartridge from the eccentric first hole portion and the second hole portion having a circular cross section, and by making the slider an eccentric multi-stage cylindrical shape, the mounting hole and the slider can be easily and highly molded. The accuracy is ensured, the slider is firmly held to prevent rattling, and it is not necessary to provide a sunk portion, so that wear due to cutting chips can be prevented. Furthermore, by providing the cartridge with a preload mechanism, the slider can be held more firmly.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a front view of the embodiment shown in FIG.

FIG. 3 is a plan view of a cartridge 13 and a slider 16 of the embodiment shown in FIG.

4 is a sectional view taken along line XX in FIG.

5 is a sectional view taken along line YY in FIG.

FIG. 6 is a perspective view schematically showing the embodiment shown in FIG.

FIG. 7 is a cross-sectional view showing a conventional cutting tool.

FIG. 8 is a ZZ sectional view in FIG.

9 is a front view of the conventional example shown in FIG.

FIG. 10 schematically shows the conventional example shown in FIG.
It is a perspective view of the slider 7 and (b) a perspective view of the tool main body 1.

[Explanation of symbols]

 5A, 5B, 5C Cutting blade tip 8 Coupling member 10 Connecting pin 11 Tool body 12 Recessed groove 13 Cartridge 15 Mounting hole 15A First hole portion 15B Second hole portion 16 Slider 16A First cylindrical portion 16B Second cylindrical portion 17 Bushing 18 Tightening screw (preload mechanism) O Axis of tool body 11

Claims (3)

[Claims] 1. A substantially conical tool body rotated about an axis is formed with a groove along a generatrix of the cone, and a mounting hole extending in the direction of the generatrix is provided in the groove. A cartridge having a cutting blade tip at its tip is slidable in the direction of the above-mentioned busbar, and its rotation around the busbar is restrained and fitted into this mounting hole. At the same time, inside the tool body, there is provided a coupling member that is rotatable integrally with the tool body and is movable back and forth along the axis to engage with the slider and slide the slider. A cutting tool characterized by being included. 2. The mounting hole comprises a first hole portion having a circular cross section having a central axis parallel to the generatrix and a second hole having a circular cross section having a central axis parallel and eccentric to the central axis of the first hole portion. And a portion of the slider that is inserted into the mounting hole is formed in an eccentric multi-stage cylindrical shape that closely contacts the inner circumferences of the first hole portion and the second hole portion. The cutting tool according to claim 1, wherein: 3. The cartridge is provided with a preload mechanism for pressing a portion of the slider, which is fitted into the mounting hole, against an inner peripheral surface of the mounting hole. The cutting tool according to 2.