JP2011206885A - Boring tool and boring method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a valve seat press-fit hole and a valve guide press-fit hole to be simultaneously formed, allow an outer diameter of a blade for forming the valve seat press-fit hole to be expanded, and easily control a diameter of the valve seat press-fit hole.SOLUTION: At a cutting tool 33 for processing the valve seat press-fit hole in a boring tool 21, the blade 33a for processing the valve seat press-fit hole is formed at a tip, a taper hole 331 tapered from a tip side toward a base end side is formed, and an insertion hole 332 communicating with the taper hole 331 from the base end side is formed. A cutting tool 31 for processing the valve guide press-fit hole has a taper shaft 310 engaging with the taper hole 331 of the cutting tool 33 for processing the valve seat press-fit hole at the base end side and includes a bolt 40 screwed to the base end of the taper shaft 310 of the cutting tool 31 for processing the valve guide press-fit hole from the insertion hole 332 side of the cutting tool 33 for processing the valve seat press-fit hole.

Description

  The present invention relates to a drilling tool and a drilling method, and more specifically, a hole into which a valve seat and a valve guide of an engine cylinder head are press-fitted is simultaneously formed in the cylinder head as a workpiece. The present invention relates to a drilling tool and a drilling method.

  Conventionally, a valve guide that holds the shaft of an intake valve or an exhaust valve of a cylinder head of an engine and a valve seat that is a valve seat of the intake valve or the exhaust valve are press-fitted into the cylinder head. For this reason, in the cylinder head, a hole into which the valve seat is press-fitted (hereinafter referred to as a valve seat press-fitting hole) and a hole into which the valve guide is press-fitted (hereinafter referred to as a valve guide press-fitting hole) Is formed).

  Further, in the valve seat press-fitting hole, the outer diameter of the blade for forming the valve seat press-fitting hole in this dedicated drilling tool is the diameter of the valve seat press-fitting hole of the cylinder head as a product. However, by repeating the drilling with a dedicated drilling tool, the blade is worn, and the outer diameter of the blade in the dedicated drilling tool gradually decreases. As a result, the diameter of the valve seat press-fitting hole of the cylinder head, which is the product, gradually decreases, and the product quality cannot be maintained. Therefore, it is necessary to maintain the outer diameter of the blade in a dedicated drilling tool at a predetermined diameter.

Therefore, Patent Document 1 discloses an ultra-precision machining tool including a mandrel, a rigid cutting blade formed around the tip of the mandrel, and a conical screw fitted into the mandrel from the center of the mandrel tip. It is shown.
According to this ultraprecision machining tool, the diameter of the rigid cutting blade can be adjusted and maintained at a predetermined diameter by operating the conical screw from the tip of the mandrel and screwing the conical screw into the mandrel.

JP 2001-524882 A

  By the way, the diameter of the valve guide press-fitting hole is smaller than the diameter of the valve seat press-fitting hole. However, with a dedicated drilling tool, the valve seat press-fitting hole and the valve guide press-fitting hole are formed simultaneously. Specifically, the dedicated drilling tool includes a valve seat press-fitting hole cutting tool for forming a valve seat press-fitting hole in the cylinder head, and a valve guide press-fitting hole cutting tool for forming a valve guide press-fitting hole in the cylinder head. . The dedicated drilling tool provides a valve seat press-fitting hole and a valve guide press-fitting hole by providing a valve guide press-fitting hole cutting tool on the tip side facing the cylinder head of the valve seat press-fitting hole cutting tool. Can be formed simultaneously.

  That is, since the valve guide press-fitting hole cutting tool is provided on the tip side of the valve seat press-fitting hole cutting tool, the blade from the tip side like the conical screw of the ultraprecision machining tool disclosed in Patent Document 1 is provided. The structure which adjusts the outer diameter of cannot be provided.

Moreover, the valve seat press-fitting hole cutting tool and the valve guide press-fitting hole cutting tool are rotated together to cut the cylinder head, thereby simultaneously forming the valve seat press-fitting hole and the valve guide press-fitting hole.
However, the blade of the valve seat press-fitting hole cutting tool has a larger outer diameter than the blade of the valve guide press-fitting hole cutting tool, so even if the rotation speed is the same, the peripheral speed is large and the cutting amount is large and wears faster. . Therefore, in a dedicated drilling tool, it may be necessary to adjust only the outer diameter of the blade of the valve seat press-fitting hole cutting tool.

  The present invention enables the valve seat press-fitting hole and the valve guide press-fitting hole to be formed at the same time, and allows the outer diameter of the blade for forming the valve seat press-fitting hole to be expanded, thereby easily managing the diameter of the valve seat press-fitting hole. The purpose is to do.

  In the drilling tool of the present invention, a hole into which a valve seat and a valve guide of an intake valve or an exhaust valve of an engine cylinder head are press-fitted is simultaneously formed in the cylinder head (for example, a cylinder head 1 described later). Valve for forming a valve seat press-fitting hole (for example, a valve seat press-fitting hole 11 described later) into which the valve seat is press-fitted. A sheet press-fitting hole cutting tool (for example, a later-described valve seat press-fitting hole cutting tool 33) and a valve guide press-fitting hole (for example, a later-described valve guide press-fitting hole 13) into which the valve guide is pressed are formed in the workpiece. A valve guide press-fitting hole cutting blade (for example, a valve guide press-fitting hole cutting tool 31 described later), and the valve A blade for forming a valve press-fit hole is formed on a tip (for example, a valve seat press-fit hole 33a to be described later) for forming the valve seat press-fit hole at the tip, and becomes narrower from the tip side toward the base end side. A tapered hole (for example, a later-described tapered hole 331) and an insertion hole (for example, a later-described insertion hole 332) communicating with the tapered hole from the base end side are formed. A proximal shaft side has a taper shaft (for example, a taper shaft 310 to be described later) that engages with the taper hole of the valve seat press-fitting hole processing blade tool, and the valve seat press-fitting hole cutting tool has the taper shaft from the insertion hole side. A bolt (for example, a bolt 40 to be described later) is provided that is screwed with the proximal end of the taper shaft of the valve guide press-fitting hole cutting tool.

  According to this invention, a valve seat press-fitting hole for forming a valve seat into which a valve seat is press-fitted, and a valve guide press-fitting hole for forming a valve guide press-fitting hole into which a valve guide is press-fitted. Since the hole machining blade is provided, the valve seat press-fitting hole and the valve guide press-fitting hole can be formed simultaneously.

  Further, according to the present invention, the valve seat press-fitting hole cutting tool has a blade for forming a valve seat press-fitting hole at the distal end, a tapered hole that narrows from the distal end side toward the proximal end side, and from the proximal end side And an insertion hole communicating with the tapered hole. Further, the valve guide press-fitting hole cutting tool has a taper shaft that engages with the taper hole of the valve seat press-fitting hole cutting tool on the base end side. Then, a bolt that engages with the proximal end of the taper shaft of the valve guide press-fitting hole cutting tool from the insertion hole side of the valve seat press-fitting hole cutting tool is provided.

As a result, when the bolt is tightened, the taper shaft of the valve guide press-fitting hole cutting tool moves toward the proximal end side of the taper hole of the valve seat press-fitting hole cutting tool. Then, the outer diameter of the blade for forming the valve seat press-fitting hole formed at the tip of the valve seat press-fitting hole processing blade is expanded. That is, by managing the tightening torque of the bolt, it is possible to manage the outer diameter of the blade for forming the valve seat press-fitting hole.
Therefore, the valve seat press-fitting hole and the valve guide press-fitting hole can be formed simultaneously, the outer diameter of the blade for forming the valve seat press-fitting hole can be expanded, and the diameter of the valve seat press-fitting hole can be easily managed.

  Further, the bolt can be tightened in the insertion hole formed from the base end side of the blade for press-fitting the valve seat press-fitting hole. Accordingly, for example, an automatic diameter expansion mechanism can be obtained by connecting a bolt to a rotating device at the insertion hole, and managing and tightening the tightening torque of the bolt with the rotating device.

  The drilling method of the present invention is a drilling method for simultaneously forming a hole into which a valve seat and a valve guide of an intake valve or an exhaust valve of an engine cylinder head are press-fitted in the cylinder head as a workpiece, A valve seat press-fitting hole for forming the valve seat into which the valve seat is press-fitted, and a valve guide press-fitting hole for forming the valve guide press-fitting hole into which the valve guide is press-fitted. A blade for forming the valve seat press-fitting hole at the distal end, a tapered hole that narrows from the distal end toward the proximal end, and a proximal end An insertion hole communicating with the taper hole from the side, and the valve guide press-fitting hole cutting tool is provided on the base end side for processing the valve seat press-fitting hole. A bolt that has a taper shaft that engages with the taper hole of the tool, and that is screwed into a base end of the taper shaft of the valve guide press-fitting hole cutting tool from the insertion hole side of the valve seat press-fitting hole cutting tool; In the drilling tool provided, by tightening the bolt with a predetermined torque, the taper shaft of the valve guide press-fitting hole cutting tool is directed toward the proximal end side of the tapered hole of the valve seat press-fitting hole cutting tool. The outer diameter of the blade of the valve seat press-fitting hole cutting tool is maintained within a predetermined diameter tolerance.

  According to this invention, a valve seat press-fitting hole for forming a valve seat into which a valve seat is press-fitted, and a valve guide press-fitting hole for forming a valve guide press-fitting hole into which a valve guide is press-fitted. Since the hole machining blade is provided, the valve seat press-fitting hole and the valve guide press-fitting hole can be formed simultaneously.

  Further, according to the present invention, the valve seat press-fitting hole cutting tool has a blade for forming a valve seat press-fitting hole at the distal end, a tapered hole that narrows from the distal end side toward the proximal end side, and from the proximal end side An insertion hole communicating with the taper hole, the valve guide press-fitting hole cutting tool has a taper shaft that engages with the taper hole of the valve seat press-fitting hole cutting tool on the base end side, and tapers from the insertion hole side. In a drilling tool equipped with a bolt that is screwed with the base end of the shaft, the taper shaft is moved toward the base end side of the taper hole by tightening the bolt with a predetermined torque, and a valve seat press-fitting hole cutting tool The outer diameter of the blade can be maintained within a predetermined diameter tolerance.

As a result, when the bolt is tightened with a predetermined torque, the taper shaft of the valve guide press-fitting hole cutting tool moves toward the proximal end side of the taper hole of the valve seat press-fitting hole cutting tool. The outer diameter of the blade for forming the valve seat press-fitting hole formed at the tip of the blade is expanded so as to have a predetermined diameter tolerance. That is, by tightening the bolt with a predetermined torque, the outer diameter of the blade for forming the valve seat press-fitting hole can be expanded to have a predetermined diameter tolerance.
Therefore, the valve seat press-fitting hole and the valve guide press-fitting hole can be formed simultaneously, the outer diameter of the blade for forming the valve seat press-fitting hole can be expanded, and the diameter of the valve seat press-fitting hole can be easily managed.

  Further, for example, a bolt is connected to a rotating device in the insertion hole, and the tightening torque of the bolt is managed and tightened by this rotating device. In this case, in the rotating device, data indicating the relationship between the tightening torque of the bolt and the diameter expansion amount of the blade for forming the valve seat press-fitting hole is stored, and automatic diameter expansion is performed by tightening the bolt based on this data. It is also possible to use a mechanism.

  According to the present invention, the valve seat press-fitting hole and the valve guide press-fitting hole can be formed at the same time, the outer diameter of the blade for forming the valve seat press-fitting hole can be expanded, and the diameter of the valve seat press-fitting hole can be easily made. Can be managed.

It is a top view of the state which showed the outline appearance composition of the cylinder head in which the valve seat press-fitting hole etc. were formed by processing of the drilling tool concerning one embodiment of the present invention, and the surface where a cylinder block is attached turned up . It is sectional drawing which shows schematic structure of the valve seat press-fitting hole, valve guide opening counterbore, and valve guide press-fitting hole which were formed in the cylinder head by the process of the drilling tool which concerns on one Embodiment of this invention. . It is a perspective view which shows schematic structure of the drilling tool which concerns on one Embodiment of this invention. It is a figure which shows schematic sectional structure of the BB 'direction shown in FIG. 3 of the drilling tool which concerns on one Embodiment of this invention. It is a figure explaining the procedure which forms a valve seat press-fitting hole, a valve guide opening counterbore, and a valve guide press-fitting hole in a cylinder head. (A) is a figure explaining the procedure which forms a valve guide opening counterbore using the valve guide opening counterbore hole cutting tool. (B) is a figure explaining the procedure which forms a valve seat press-fitting hole and a valve guide press-fitting hole using the drilling tool which concerns on one Embodiment of this invention. It is a fragmentary sectional view near the volt | bolt of the drilling tool which concerns on one Embodiment of this invention. It is a graph which shows the relationship between the diameter expansion amount for every thickness of the cutting tool for valve seat press-fitting hole processing, and tightening torque. It is a figure which shows schematic sectional structure of the drilling tool which is the 1st modification of one Embodiment of this invention. It is a schematic diagram of the automatic diameter expansion mechanism to which the drilling tool which is the 2nd modification of one Embodiment of this invention is applied. It is explanatory drawing of schematic structure of the drilling tool which is the 2nd modification of one Embodiment of this invention. It is a figure which shows schematic sectional structure of the BB 'direction shown in FIG. 10 of the drilling tool which is the 2nd modification of one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
FIG. 1 shows a schematic external configuration of a cylinder head 1 in which a valve seat press-fitting hole 11 and the like are formed by processing a drilling tool according to an embodiment of the present invention, and a surface on which a cylinder block is attached is turned up. It is a top view of a state.

  The cylinder head 1 has a valve seat press-fitting hole 11 into which a valve seat (not shown) of an intake valve or an exhaust valve is press-fitted and a suction valve or an exhaust in a central portion on a surface to which a cylinder block (not shown) is attached. A valve guide press-fitting hole 13 into which a valve guide (not shown) that slidably supports a valve stem (not shown) is press-fitted is formed, and a bolt hole 14 for attaching a cylinder block is formed around them. A water jacket 15 or the like that is a flow path for flowing the cooling water is formed.

  FIG. 2 shows a valve seat press-fitting hole 11, a valve guide opening counterbore 12, and a valve guide press-fitting hole 13 formed in the cylinder head 1 by machining a drilling tool according to an embodiment of the present invention. It is sectional drawing which shows schematic structure.

The cylinder head 1 is processed by the drilling tool according to the embodiment of the present invention from the surface of the cylinder head 1 toward the inside around the line XX ′ in FIG. 2 (upper in FIG. 2). The valve seat press-fitting hole 11, the valve guide opening counterbore 12, and the valve guide press-fitting hole 13 are formed concentrically in that order.
In the cylinder head 1, an intake or exhaust port 10 is formed between the valve seat press-fitting hole 11 and the valve guide opening counterbore 12. For this reason, as shown in FIG. 2, the depth of the valve guide opening counterbore 12 is not uniform and varies depending on the shape of the intake or exhaust port 10.

FIG. 3 is a perspective view showing a schematic configuration of the drilling tool 21 according to one embodiment of the present invention.
Hereinafter, a processing object of the drilling tool 21, that is, an object on which the valve seat press-fitting hole 11 (see FIG. 2) and the valve guide press-fitting hole 13 (see FIG. 2) are formed is referred to as a workpiece. In the present embodiment, the cylinder head 1 (see FIG. 2) serves as a workpiece. In this embodiment, the valve guide opening counterbore 12 (see FIG. 2) is attached to the cylinder head 1 by a valve guide opening counterbore hole cutting tool 32 (see FIG. 5A) different from the drilling tool 21. It is formed.

  In order from the left end in FIG. 3, the drilling tool 21 and the valve seat press-fitting hole are sequentially formed so that the drilling tool 21 can rotate around the axis indicated by the line AA ′ in FIG. 3. The cutting tool 33 is concentrically provided, and has a bolt 40 (see FIG. 4) that connects the valve guide press-fitting hole cutting tool 31 and the valve seat press-fitting hole cutting tool 33.

A plurality of valve guide press-fitting hole processing blades 31a are formed uniformly on the valve guide press-fitting hole processing blade 31 in a radial direction from the shaft. The length in the radial direction from the shaft to each valve guide press-fitting hole processing blade 31a is substantially the same as the radius of the valve guide press-fitting hole 13 and the length in the axial direction of the valve guide press-fitting hole 31a is The depth substantially coincides with the depth of the valve guide press-fitting hole 13 (see FIG. 2).
Accordingly, the valve guide press-fitting hole cutting blade 31 formed with such a plurality of valve guide press-fitting hole processing blades 31a is rotated about the axis while being inserted into the workpiece, so that the valve guide press-fitting hole 13 is rotated. Is formed in the workpiece.
The cross-sectional configuration of the valve guide press-fitting hole machining blade 31 will be described later.

In the valve seat press-fitting hole cutting tool 33, a plurality of valve seat press-fitting hole cutting blades 33a are formed uniformly at the tip (end in the direction of arrow F shown in FIG. 3) radially from the shaft. The length in the radial direction from the shaft to each valve seat press-fitting hole processing blade 33a is substantially equal to the radius of the valve seat press-fitting hole 11 (see FIG. 2). The length in the direction substantially coincides with the depth of the valve seat press-fitting hole 11.
Therefore, the valve seat press-fitting hole cutting tool 33 in which such a plurality of valve seat press-fitting hole processing blades 33a are formed is rotated around the axis while being inserted into the workpiece, so that the valve seat press-fitting hole 11 is obtained. Is formed in the workpiece.

Further, the outer diameter of the valve seat press-fitting hole processing blade 33a is larger than the outer diameter of the valve guide press-fitting hole processing blade 31a because the diameter of the valve seat press-fitting hole 11 is larger than the diameter of the valve guide press-fitting hole 13.
Therefore, the valve seat press-fitting hole processing blade 33a and the valve guide press-fitting hole processing blade 31a are used for drilling at the same rotational speed, but the valve seat press-fitting hole cutting blade 33a has a higher peripheral speed and is cut. The amount is large and wears faster.
The sectional configuration of the valve seat press-fitting hole cutting tool 33 will be described later.

Next, the cross-sectional configuration of the drilling tool 21 will be described.
FIG. 4 is a diagram showing a schematic cross-sectional configuration in the BB ′ direction shown in FIG. 3 of the drilling tool 21 according to one embodiment of the present invention.
The valve guide press-fitting hole cutting tool 31 is a rod-like body extending around the axis indicated by the line AA ′ in FIG. 4, and has a taper shaft 310 formed on the base end side (in the direction of arrow T shown in FIG. 4). And a blade portion 311 formed with a valve guide press-fitting hole processing blade 31a formed on the tip side (in the direction of arrow F shown in FIG. 4) from the taper shaft 310.

  The taper shaft 310 is formed with a taper dimension conforming to the Morse taper standardized as the shape of the shank of the drill, and from the distal end side (the direction of arrow F shown in FIG. 4) to the proximal end side (the direction of arrow T shown in FIG. 4). ) Is formed to become narrower. Further, a screw hole 310 a that is screwed into the neck portion 40 b of the bolt 40 is formed at the proximal end of the taper shaft 310.

  The valve seat press-fitting hole cutting tool 33 extends around the axis indicated by the line AA ′ in FIG. 4, and a valve seat press-fitting hole cutting blade 33a is formed on the tip side (in the direction of arrow F in FIG. 4). In the main body 330, a tapered hole 331 that narrows from the distal end side (in the direction of arrow F shown in FIG. 4) toward the proximal end side (in the direction of the arrow T shown in FIG. 4), and a tapered hole 331 from the proximal end side. An insertion hole 332 extending toward the center and a communication hole 333 that connects the taper hole 331 and the insertion hole 332 are formed.

  The tapered hole 331 is formed with a taper dimension that conforms to the Morse taper standardized as the shape of the drill shank, and engages with the tapered shaft 310 of the valve guide press-fitting hole cutting tool 31. The valve guide press-fitting hole cutting tool 31 is fixed to the valve seat press-fitting hole cutting tool 33 by the taper shaft 310 engaging with the taper hole 331.

The insertion hole 332 is formed with a diameter larger than the outer diameter of the head 40 a of the bolt 40. The communication hole 333 is formed with a diameter smaller than the outer diameter of the head portion 40a of the bolt 40, and is formed with a diameter larger than the outer diameter of the neck portion 40b of the bolt 40. The axial length is shorter than the length of the neck portion 40b. Is formed.
That is, the bolt 40 has a head portion 40a locked to the bottom portion 332a of the insertion hole 332, a neck portion 40b penetrating the communication hole 333 and protruding into the tapered hole 331, and a part of the protruding neck portion 40b is a valve guide. The screw hole 310a of the press-fitting hole processing blade 31 is screwed.

Next, a procedure for drilling the cylinder head 1 with the drilling tool 21 will be described.
FIG. 5 is a diagram illustrating a procedure for forming the valve seat press-fitting hole 11, the valve guide opening counterbore 12, and the valve guide press-fitting hole 13 in the cylinder head 1. FIG. 5A is a view for explaining the procedure for forming the valve guide opening counterbore 12 using the valve guide opening counterbore hole cutting tool 32. FIG. 5B is a diagram illustrating a procedure for forming the valve seat press-fitting hole 11 and the valve guide press-fitting hole 13 using the drilling tool 21 according to the embodiment of the present invention.

First, the valve guide opening counterbore hole cutting tool 32 is attached to a spindle shaft rotated by a predetermined machine tool (not shown). In this case, the axis of the valve guide opening counterbore hole cutting tool 32 (axis along line AA ′ in FIG. 5A) is made to coincide with the spindle axis.
Next, as shown in FIG. 5A, the valve guide opening counterbore hole cutting tool 32 is rotated by the spindle shaft, and the valve guide opening counterbore hole cutting tool 32 is inserted into the cylinder head 1. Then, the valve guide opening counterbore 12 is formed in the cylinder head 1. Thereafter, the valve guide opening counterbore hole cutting tool 32 is pulled out from the cylinder head 1.

Next, the drilling tool 21 is attached to a spindle shaft that is rotated by a predetermined processing device (not shown). In this case, the axis of the drilling tool 21 (the axis along the line AA ′ in FIG. 5B) is made to coincide with the spindle axis.
Next, as shown in FIG. 5B, the drilling tool 21 is rotated by the spindle shaft, and the valve guide press-fitting hole cutting tool 31 and the valve seat press-fitting hole cutting tool 33 of the drilling tool 21 are moved. , Inserted into the cylinder head 1. Then, the valve seat press-fitting hole 11 and the valve guide press-fitting hole 13 are formed. Thereafter, the drilling tool 21 is pulled out from the cylinder head 1.

  When the drilling of the cylinder head 1 is repeated according to the above procedure, the valve seat press-fitting of the valve seat press-fitting hole cutting tool 33 having a larger outer diameter than the valve guide press-fitting hole 31a of the valve guide press-fitting hole 31. Since the hole machining blade 33a is worn first, the outer diameter of the valve seat press-fitting hole machining blade 33a is expanded.

Next, a procedure for expanding the outer diameter of the valve seat press-fitting hole-forming blade 33a in the drilling tool 21 will be described.
FIG. 6 is a partial cross-sectional view of the vicinity of the bolt 40 of the drilling tool 21 according to one embodiment of the present invention.
First, the bolt 40 is tightened with a predetermined torque. Then, the taper shaft 310 of the valve guide press-fitting hole cutting blade 31 moves toward the base end side (direction of arrow T shown in FIG. 6) of the taper hole 331 of the valve seat press-fitting hole cutting tool 33, and the valve seat press-fitting hole. The outer diameter of the valve seat press-fitting hole processing blade 33a formed at the tip of the processing blade 33 is expanded so as to maintain a predetermined diameter tolerance.

Here, the predetermined torque is calculated from the thickness value (mm) of the valve seat press-fitting hole processing blade 33 and the value (mm) of the diameter expansion amount of the outer diameter of the valve seat press-fitting hole cutting blade 33a. The tightening torque value (N · m).
FIG. 7 is a graph showing the relationship between the amount of diameter expansion and the tightening torque for each thickness of the valve seat press-fitting hole cutting tool.

In FIG. 7, the vertical axis represents the diameter expansion amount, and the horizontal axis represents the tightening torque. In the graph line, the triangle indicates the thickness t1, the rhombus indicates the thickness t2, the square indicates the thickness t3, and the circle indicates the thickness t4. The thicknesses are t1, t2, t3, t4 in this order. The thickness value increases.
As shown in FIG. 7, the larger the tightening torque, the larger the diameter expansion amount. That is, the predetermined torque increases as the diameter expansion amount increases as the wear amount of the valve seat press-fitting hole processing blade 33a (see FIG. 6) increases.
The amount of wear of the valve seat press-fitting hole processing blade 33a can be calculated from the number of drilling operations. That is, the wear amount of the valve seat press-fitting hole machining blade 33a when the predetermined number of holes are drilled is measured in advance, and this measured value is multiplied by the ratio between the actual number of holes drilled and the predetermined number of times. By doing so, the amount of wear at the actual number of drilling operations can be calculated. Then, the calculated wear amount can be used as the diameter expansion amount, and a predetermined torque can be calculated based on the graph shown in FIG.

  The predetermined diameter tolerance is defined as the standard tool tolerance obtained by subtracting the safety amount from the upper limit tool tolerance which is the upper limit of the outer diameter of the valve seat press-fitting hole machining blade 33a. The value obtained by subtracting the correction value. The predetermined diameter tolerance is set within a range in which an upper limit value and a lower limit value are determined.

Next, a drilling tool 21A that is a first modification of the drilling tool 21 of the present embodiment will be described.
FIG. 8 is a diagram showing a schematic cross-sectional configuration of a drilling tool 21A that is a first modification of the embodiment of the present invention.
The drilling tool 21A is different from the drilling tool 21 in that a bolt shaft 310b is formed on a tapered shaft 310A of a valve guide press-fitting hole cutting tool 31A, and a nut 45 is screwed into the bolt shaft 310b.

  The bolt shaft 310b extends from the base end (in the direction of arrow T shown in FIG. 8) of the taper shaft 310A, and penetrates the communication hole 333 of the valve seat press-fitting hole cutting tool 33.

The nut 45 is locked to the bottom portion 332a of the insertion hole 332 of the valve seat press-fitting hole processing blade 33, and is screwed with the bolt shaft 310b of the valve guide press-fitting hole cutting tool 31A.
The nut 45 has a nut main body 45a formed with an outer diameter larger than the inner diameter of the communication hole 333, and a nut screw hole 45b formed on the distal end side (in the direction of arrow F shown in FIG. 8) of the nut main body 45a and screwed into the bolt shaft 310b. And a tightening hole 45c formed on the base end side of the nut main body 45a (in the direction of arrow T shown in FIG. 8).
For example, the inner shape of the fastening hole 45c is a hexagonal shape. The fastening hole 45c is engaged with, for example, a rotary shaft (not shown) formed in a hexagonal shape.

Next, a procedure for expanding the outer diameter of the valve seat press-fitting hole processing blade 33a in the hole drilling tool 21A will be described.
First, a rotating shaft (not shown) is inserted from the base end side (in the direction of arrow T shown in FIG. 8) of the insertion hole 332 and engaged with the tightening hole 45 c of the nut 45. Then, the nut 45 is tightened with a predetermined torque. Then, the taper shaft 310A of the valve guide press-fitting hole cutting tool 31A moves toward the base end side (direction of arrow T shown in FIG. 8) of the taper hole 331 of the valve seat press-fitting hole cutting tool 33, and the valve seat press-fitting hole. The outer diameter of the valve seat press-fitting hole processing blade 33a formed at the tip of the processing blade 33 is expanded so as to maintain a predetermined diameter tolerance.

Next, an automatic diameter expansion mechanism 100 to which a drilling tool 21B that is a second modification of the drilling tool 21 of the present embodiment is applied will be described.
FIG. 9 is a schematic diagram of an automatic diameter expansion mechanism 100 to which a drilling tool 21B that is a second modification of the embodiment of the present invention is applied.
The automatic diameter expansion mechanism 100 includes a drilling tool 21B and a processing device 50 to which the drilling tool 21B is connected.

  The machining apparatus 50 includes a machining motor 51 that rotationally drives the drilling tool 21B, a diameter expansion motor 52 that expands the diameter of the valve seat press-fitting hole machining blade 33a of the drilling tool 21B, and a drilling. A motor shaft 53 that is connected to the worm 41b of the processing tool 21B and applies the rotational force obtained from the diameter expansion motor 52 by a bolt 40A, a detection unit 54 that detects the rotational torque of the motor shaft 53, a processing motor 51, and a diameter expansion. And a controller 55 connected to the motor 52 and the detection unit 54 for controlling them.

  The control device 55 stores data relating to the amount of wear of the valve seat press-fitting hole processing blade 33a of the valve seat press-fitting hole processing blade 33A according to the number of times the drilling process is performed by the drilling tool 21B. Further, the control device 55 stores data relating to the rotational torque value of the motor shaft 53 in accordance with the wear amount of the valve seat press-fitting hole processing blade 33a. The control device 55 can also store the number of rotations of the motor shaft 53 according to the amount of wear of the valve seat press-fitting hole processing blade 33a. In this case, the detection unit 54 detects the rotation speed of the motor shaft 53.

  FIG. 10 is an explanatory diagram of a schematic configuration of a drilling tool 21B which is a second modification of the embodiment of the present invention. FIG. 11 is a diagram showing a schematic cross-sectional configuration in the BB ′ direction shown in FIG. 10 of a drilling tool 21B which is a second modification of the embodiment of the present invention.

  In the drilling tool 21B, a worm wheel 41a is formed on the head of the bolt 40A, and a worm hole 334 that accommodates a worm 41b that engages with the worm wheel 41a is formed. And different.

  The worm wheel 41a and the worm 41b of the bolt 40A constitute a worm gear. Further, the motor shaft 53 of the processing device 50 is connected to the head of the worm 41b. As a result, the motor shaft 53 rotates around the rotation axis (CC ′ line shown in FIG. 11), so that the bolt 40A is the rotation axis of the drilling tool 21B (AA ′ line shown in FIG. 11). Rotate around.

The worm hole 334 is a motor that extends in a direction orthogonal to the rotation axis of the drilling tool 21B (AA ′ line in FIG. 11) in the main body 330A of the valve seat press-fitting drilling tool 33A of the drilling tool 21B. The shaft 53 is formed around the rotation axis (CC ′ line shown in FIG. 11). In addition, a worm 41b is disposed at the approximate center of the worm hole 334. The drilling tool 21B is rotationally balanced with the worm 41b disposed in the worm hole 334.
The rotating shaft (CC ′ line shown in FIG. 11) of the motor shaft 53 is connected to the radius of the inner diameter of the worm wheel 41a from the rotating shaft (AA ′ line shown in FIG. 11) of the drilling tool 21B. It is separated by a distance including the radius of the outer shape of 41b.

Thereby, the automatic diameter expansion mechanism 100 operates as follows.
The control device 55 controls the machining motor 51 to determine the center of the worm hole 334 of the drilling tool 21B when it is determined that the number of drilling operations performed by the drilling tool 21B has reached a predetermined number. Is aligned with the rotation axis of the motor shaft 53 (CC ′ line shown in FIG. 11).
Next, the control device 55 calculates the wear amount of the valve seat press-fitting hole processing blade 33a corresponding to the predetermined number of times. Further, the control device 55 calculates and stores in advance the rotational torque value of the motor shaft 53 corresponding to the calculated wear amount.

  Next, the control device 55 brings the tip of the motor shaft 53 close to the head of the worm 41b and connects it. Then, the control device 55 rotates the motor shaft 53 by the diameter expansion motor 52 and tightens the bolt 40A. Then, when the control device 55 determines that the rotation torque of the motor shaft 53 detected by the detection unit 54 has reached the rotation torque value calculated and stored in advance, the rotation drive of the diameter expansion motor 52 is stopped. Then, the taper shaft 310 of the valve guide press-fitting hole cutting tool 31 moves toward the base end side (the direction of arrow T shown in FIG. 11) of the taper hole 331 of the valve seat press-fitting hole cutting tool 33A. The outer diameter of the valve seat press-fitting hole processing blade 33a formed at the tip of the processing blade 33A is expanded so as to maintain a predetermined diameter tolerance.

According to this embodiment, there are the following effects.
For cutting a valve guide press-fitting hole for forming a valve seat press-fitting hole 13 for forming a valve seat press-fitting hole 13 for forming a valve seat and a valve guide press-fitting hole 13 for press-fitting a valve guide. Therefore, the valve seat press-fitting hole 11 and the valve guide press-fitting hole 13 can be formed simultaneously.

Further, when the bolt 40 is tightened with a predetermined torque, the taper shaft 310 of the valve guide press-fitting hole machining blade 31 moves toward the proximal end side of the taper hole 331 of the valve seat press-fitting hole cutting tool 33, and the valve seat press-fitting is performed. The valve seat press-fitting hole processing blade 33a formed at the tip of the hole processing blade 33 is expanded so that the outer diameter has a predetermined diameter tolerance. That is, by managing the tightening torque of the bolt 40, the outer diameter of the valve seat press-fitting hole 33a can be managed. More specifically, by tightening the bolt 40 with a predetermined torque, the outer diameter of the valve seat press-fitting hole processing blade 33a can be expanded to have a predetermined diameter tolerance.
Therefore, the valve seat press-fitting hole and the valve guide press-fitting hole can be formed simultaneously, the outer diameter of the blade for forming the valve seat press-fitting hole can be expanded, and the diameter of the valve seat press-fitting hole can be easily managed.

  Moreover, if the 2nd modification of this embodiment is applied, the bolt 40A will be rotated by the processing apparatus 50 via the worm 41b, and the tightening torque of the bolt 40A will be managed and tightened. In this case, the control device 55 of the processing device 50 stores data indicating the relationship between the tightening torque of the bolt 40A and the diameter expansion amount of the valve seat press-fitting hole processing blade 33a, and tightening the bolt 40A based on this data, It is also possible to provide an automatic diameter expansion mechanism 100 that can automatically maintain the outer diameter of the valve seat press-fitting hole machining blade 33a at a predetermined diameter tolerance.

  It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.

DESCRIPTION OF SYMBOLS 1 Cylinder head 11 Valve seat press-fitting hole 13 Valve guide press-fitting hole 21 Drilling tool 31 Valve guide press-fitting drilling tool 310 Tapered shaft 33 Valve seat press-fitting drilling tool 33a Valve seat press-fitting drilling tool 331 Taper hole 332 Insertion Hole 40 bolt

Claims (2)

A drilling tool that simultaneously forms a hole into which a valve seat and a valve guide of an intake valve or an exhaust valve of a cylinder head of an engine are press-fitted in the cylinder head as a workpiece,
A valve seat press-fitting hole forming tool for forming a valve seat press-fitting hole into which the valve seat is press-fitted, and
A valve guide press-fitting hole into which the valve guide is press-fitted, and a valve guide press-fitting hole machining blade for forming the workpiece,
The valve seat press-fitting hole cutting tool has a blade for forming the valve seat press-fitting hole at the distal end, a tapered hole that narrows from the distal end side toward the proximal end side, and communicates with the tapered hole from the proximal end side An insertion hole to be formed,
The valve guide press-fitting hole cutting tool has a taper shaft that engages the taper hole of the valve seat press-fitting hole cutting tool on the base end side,
A drilling tool comprising a bolt that is screwed to a base end of the taper shaft of the valve guide press-fitting hole cutting tool from the insertion hole side of the valve seat press-fitting hole cutting tool. A drilling method for simultaneously forming a hole into which a valve seat and a valve guide of an intake valve or an exhaust valve of a cylinder head of an engine are press-fitted in the cylinder head as a workpiece,
A valve seat press-fitting hole forming tool for forming a valve seat press-fitting hole into which the valve seat is press-fitted, and
A valve guide press-fitting hole into which the valve guide is press-fitted, and a valve guide press-fitting hole machining blade for forming the workpiece,
The valve seat press-fitting hole cutting tool has a blade for forming the valve seat press-fitting hole at the distal end, a tapered hole that narrows from the distal end side toward the proximal end side, and communicates with the tapered hole from the proximal end side An insertion hole to be formed,
The valve guide press-fitting hole cutting tool has a taper shaft that engages the taper hole of the valve seat press-fitting hole cutting tool on the base end side,
In a drilling tool comprising a bolt that is screwed with a base end of the taper shaft of the valve guide press-fitting hole cutting tool from the insertion hole side of the valve seat press-fitting hole cutting tool,
By tightening the bolt with a predetermined torque, the taper shaft of the valve guide press-fitting hole cutting tool is moved toward the proximal end side of the taper hole of the valve seat press-fitting hole cutting tool, and the valve seat press-fitting is performed. A drilling method for maintaining an outer diameter of the blade of a drilling tool within a predetermined diameter tolerance.

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