JPH01183306A - Method for machining bearing member and device thereof - Google Patents

Abstract

PURPOSE:To obtain the roundness of a bearing hole in a finally assembled condition by forming the bearing hole having a sectional shape constructed by an envelope the center of which is very slightly offset in a drilling process in due consideration of a strain generated in a bearing member. CONSTITUTION:A stage 4 is positioned by a horizontal positioning pin 18 and an up/down positioning block 20 and is pressed from an upside, in a cylinder head 2, the first drilling process of a bearing hole 6 is carried out by means of a bite 26. Next, a minute adjustment pin 10 the upper end of which is located lower than the upper end of the up/down positioning block 20 rises in a predetermined volume, the stage 4 and the cylinder block 2 are risen in a predetermined minute volume and a machined core A is relatively offset is a predetermined volume for the core of the bearing hole 6. Under this condition, the bite 26 is abutted to the inner circumference of a cylinder head 2 by rotation and retreat of a rotary shaft 28 due to drive of a motor so as to conduct the secondary drilling process to complete the process. The sectional shape of a bearing hole 6 constructed by the secondary process becomes the envelope of two circle the centers of which are minutely offset upward and downward.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a processing method and apparatus for forming a bearing hole in a bearing member.

(Prior art) When forming a bearing hole in a bearing member, it is important to ensure sufficient circularity of the bearing hole in order to function as a bearing member. When the bearing member is assembled to a member by tightening bolts or the like, the roundness obtained by the bearing member itself may also be reduced by the assembly.

Particularly, when bolts are tightened near a bearing hole for a camshaft, such as in a cylinder head, the strain caused by assembly cannot be ignored functionally.

For this reason, conventionally, the drilling of the bearing hole is generally performed by tightening bolts or the like to bring the bearing member into the same stress state as in the final assembled state.

Furthermore, Japanese Patent Application Laid-Open No. 62-28102 discloses a technique for creating the above-mentioned stress state by pressing a bearing member with a predetermined suppressing means.

(Issue 8 to be solved by the invention) However, when drilling the bearing member in the same stress state as the final assembled state, troublesome work such as bolt tightening and bolt removal is required. Otherwise, there is a risk that the bearing member will be damaged when pressed by the suppressing means.

The present invention has been made in view of these circumstances, and it is possible to improve the final state of the bearing member assembled to other members without applying a predetermined stress state to the bearing member during drilling. It is an object of the present invention to provide a method and apparatus for processing a bearing member that can sufficiently ensure the roundness of a bearing hole in an assembled state.

(Means for Solving the Problems) The bearing member processing method and apparatus according to the present invention take into consideration in advance the strain that will occur in the bearing member in the final assembled state, and the center of the bearing member will be slightly deviated during the drilling process. Few (
The above objective is achieved by forming a bearing hole having a cross-sectional shape consisting of envelope lines of two circles. That is, the method for processing a bearing member according to the present invention includes the steps of forming a bearing hole in a bearing member.
By shifting the position of the machining center by a predetermined minute amount to the bearing member and performing the drilling process twice,
This is characterized by forming two bearing holes. Further, the bearing member processing apparatus according to the present invention includes a mounting table on which the bearing member is placed, and a hole-drilling tool for processing a bearing hole in the horizontal direction by reciprocating in the direction of the processing center in the bearing member on the mounting table. and processing center adjustment that shifts the relative position of the processing center of the drilling tool and the bearing member on the mounting table by a predetermined minute amount in the vertical direction when the drilling tool moves forward and when it retreats. It is characterized by comprising means.

The above-mentioned "predetermined minute amount" means the amount by which the bearing hole can be made into a nearly perfect circle due to the strain that occurs in the bearing member in the final assembled state, and is defined as It should be set as appropriate.

The above-mentioned "machining center adjustment means" is a device that can shift the relative position of the machining core of the hole-drilling tool and the bearing member on the mounting table by a predetermined minute amount in the vertical direction. Furthermore, the structure for shifting is not limited to a specific structure.

(Function) As shown in the above structure, the method for processing a bearing member according to the present invention includes drilling the bearing member at least twice while shifting the position of the processing core by a predetermined minute amount.
Since one bearing hole is formed, the direction and amount of shift in the position of the machining center and the number of drilling operations are determined depending on the direction and degree of strain that occurs in the bearing member in the final assembled state. By setting , a substantially perfect circular bearing hole will be formed in the bearing member in the final assembled state. Further, the bearing member processing device according to the present invention changes the relative position of the processing core of the drilling tool and the bearing member on the mounting body in the vertical direction when the drilling tool moves forward and when it retreats. Since the bearing member is shifted by a predetermined minute amount, the assembly angle of the bearing member to the mounting table is set depending on the direction of the strain that will occur in the bearing member in the final assembled state, and the angle at which the bearing member is attached to the mounting table is set depending on the degree of the strain. By setting the amount of relative position shift, a substantially perfect circular bearing hole will be formed in the bearing member in the final assembled state.

(Effects of the Invention) Therefore, according to the present invention, the final assembly in which the bearing member is assembled to other members can be achieved without applying a predetermined stress state to the bearing member during drilling process as in the past. It is possible to ensure sufficient roundness of the bearing hole in the attached state, which eliminates the need for troublesome work such as tightening and removing bolts during drilling. The risk of damage can also be avoided.

(Examples) Examples of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of a bearing member processing apparatus according to the present invention.

This processing device includes a mounting table 4 on which a cylinder head 2, which is a bearing member, is placed, and a cylinder head 2 on this mounting table 4.
A boring bar 8 is a drilling tool for horizontally machining a bearing hole 6 for a camshaft by reciprocating in the direction of the machining core A, and when this boring bar 8 moves forward and retreats, A fine adjustment pin l is a processing center adjusting means for vertically shifting the relative position of the processing center A of the boring bar 8 and the cylinder head 2 on the mounting table 4 by a predetermined minute amount.
It is equipped with O.

There are a total of seven bearing holes 6 for the camshaft in the cylinder head 2, and these are already formed into hole shapes, albeit with rough accuracy, at the time of machining with the boring bar 8. This cylinder head 2 is mounted on a mounting table 4.
The core of each bearing hole 6 is positioned parallel to the processing core A of the boring bar 8 by the plurality of positioning pins 12 .

The mounting table 4 consists of a mounting plate 14 and the positioning pin 12 provided on its upper surface, and is positioned in the horizontal and vertical directions by a horizontal positioning pin 18 and a vertical positioning block 20 fixedly installed on the fixed table 1B. ,
This makes it possible to perform the above positioning with respect to the cylinder head 2. Horizontal positioning pin 1
8 performs positioning by fitting with the positioning bush 14a of the mounting plate 14, and the vertical positioning block 20 performs positioning by coming into contact with the lower surface of the mounting plate 14.

The cylinder head 2 is clamped to the mounting plate 14 by a clamping means (not shown), and the mounting plate 14 is pressed from above by a pressing pin (not shown). Also, vibrations and the like are prevented from occurring on the mounting table 4.

The boring bar 8 includes a bar body 22 extending in the horizontal direction, and a support portion 24 that fixedly supports the base end of the bar body 22.
and seven cutting tools 2B attached at predetermined intervals on the same generatrix on the outer circumferential surface of the bar body 22, and while the bar body 22 rotates, the machining core (i.e., the bar body 22
When reciprocating in direction A), the seven bearing holes 6 of the cylinder head 2 are polled using seven bits 2B. The bar body 22 is rotated by a motor driving force transmitted through a support portion 24 connected to an output shaft 28 of a motor (not shown).

Further, the reciprocating movement of the bar body 22 is made by other driving means (not shown). The tip of the bar body 22 is adapted to fit into the cylindrical member 30 via a key 32 during drilling, thereby rotating the cylindrical member 30 together with the bar body 22.

The fine adjustment pin 1O has the illustrated position and a position in which the upper end surface protrudes a predetermined minute amount (for example, 50 μm when the inner diameter of the bearing hole 6 is φ43.5 am) above the upper end face of the vertical positioning block 20. The mounting table 1B is vertically movable so that the mounting table 4 and the cylinder 2 placed thereon can be moved to the boring bar 8.
It can be shifted upward by a predetermined minute amount from the position shown in the figure.

FIG. 2 is a plan view taken along the line ■--■ in FIG. 1.

The fine adjustment pins 1O and the vertical positioning blocks 22 are provided at four locations corresponding to the four corners of the mounting table 4, and the left and right positioning pins 18 are provided at two of these locations located diagonally. A lifter pin 34 is provided on the boring bar 8 side of each fine adjustment pin IO. The lifter pin 34 has substantially the same structure as the fine adjustment pin IO, and is designed to move up and down, but when raised, it assumes a position protruding above the fine adjustment pin 10 by a predetermined amount.

3 and 4 are sectional views taken along the lines ■--■ and ■--■ in FIG. 2.

As shown in FIG. 3, the lifter pin 34 has a pin body 36
, a contact head 38 attached to the upper end of this pin body 3B, a ring-shaped liner 40 for adjusting the height of the upper end surface of this contact head 38, and a contact head 38 attached to the upper end of the pin body 3B. The lower end of the pin body 3B consists of a double cylindrical member 44.
The slider 48 is engaged with a hook-shaped groove 48a of a slider 48 that slides within the slider 8 in a direction perpendicular to the paper surface.

As shown in FIG. 4, the slider 48
As the shaft 50 passing through the cylindrical member 4B reciprocates in its axial direction, it slides within the cylindrical member 4B. The groove portion 48a of the slider 48 is formed to be inclined upward to the right as shown in the figure, so when the slider 48 slides to the left, the lid pin 34 rises within the sleeve 52, and when it slides to the right, It will descend.

Like the lifter pin 34, the fine adjustment pin 1G also includes a pin body 54, a contact head 56, a liner 58, and a bolt (not shown), and the lower end of the pin body 54 has a double cylindrical member 60. It engages with the groove 66a of the slider 8B that slides therein together with the shaft 84. However, the pin body 54 has a shorter axis than the pin body 36, and a stopper ring 68 is fixed near its lower end.
The upper surface abuts against the lower end surface of the sleeve 70 to prevent it from rising any further. Therefore, by appropriately selecting the thickness of the liner 58, when the stopper ring B8 comes into contact with the sleeve 70, the upper end surface of the contact head 5B will be at a position higher than the upper end surface of the vertical positioning block 20 by a predetermined minute amount. It becomes possible to do so. Further, the slope of the groove portion 86a of the slider 66 is
It is formed more slowly than that of . As a result, even if the sliders 66 and 48 are slid at the same speed, the vertical movement speed of the fine AIi pin 10 is smaller than that of the lifter pin 36, making fine adjustment easier.

Next, the operation of this embodiment will be explained.

As shown in FIG. 1, the mounting table 4 on which the cylinder head 2 is mounted and clamped is positioned by the horizontal positioning pin 18 and the vertical positioning block 20, and the pressing pin (
(not shown) from above, the cylinder head 2 becomes ready for drilling the bearing hole 6.

Next, the boring bar 8 is moved from the right to the left in the figure (i.e., the machining center A
Move forward in the direction (towards the left). Then, the boring bar 8 is stopped at a position where the tip of the bar body 22 passes through the seven bearing holes 6 and is inserted into the cylindrical member 30, and each bite 26 reaches near the right end of each bearing hole 6. do. During this forward movement, the cylinder head 2 is raised upward by a predetermined amount together with the mounting table 4 in order to prevent the cutting edge of the cutting tool 26 from interfering with the bearing hole 6. This elevation is achieved by the slider 48 sliding to the left by a predetermined amount in FIG. 4, thereby raising the lifter pin 34 by a predetermined amount. When the advance of the boring bar 8 is completed, the slider 48 slides to the right by a predetermined amount, the lifter bin 34 descends to its original position, and as shown in FIG. It descends to a position where it abuts the vertical positioning pin 20. As a result, the machining center A of the boring bar 8 is brought into a state where it substantially coincides with the center of the bearing hole 6 of the cylinder head 2, and preparation for the first drilling process is completed.

The first drilling process was performed using the motor-driven output/force shaft 2.
8 and the output shaft 28 moves forward, the cutting tool 2
6 is brought into contact with the inner circumferential surface of the bearing hole 6 of the cylinder head 2 and polling is performed. FIG. 1 shows the state immediately after the first drilling process is completed.

When the first drilling process is completed, the fine adjustment pin IO whose upper end surface is located below the upper end surface of the vertical positioning block 20 is raised by a predetermined amount by sliding of the slider 8B (see Fig. 4). . This rise causes the fine adjustment pin lO
The upper end surface protrudes above the upper end surface of the vertical positioning block 20 by a predetermined minute amount. Along with this, the mounting table 4 and the cylinder block 2 also rise by a predetermined minute amount, and the machining core A is displaced downward by a predetermined minute amount relative to the core of the bearing hole 6.

In this state, the second drilling process is performed.

That is, the rotation of the output shaft 28 by the motor drive and the retraction of the output shaft cause the cutting tool 2B to be moved to the cylinder head 2.
This is done by poling the inner peripheral surface of the

When the second drilling process is completed, the lifter pin 34 rises again, and then the boring bar 8 retreats with the cutting tool 26 facing directly upward, and the tip of the bar body 8 moves from the rightmost bearing hole 6. When removed, the lifter pin 34 and fine adjustment pin 10 descend to their original positions.

Through the above steps, the drilling process is completed, but the bearing hole 6 of the cylinder head 2 formed by the above two drilling processes is
The cross-sectional shape of is 2 whose center is shifted by a predetermined minute amount in the vertical direction.
It becomes the envelope of two circles. For this reason, when the cylinder head 2 is later attached to the cylinder block by tightening bolts or the like on both the left and right sides of the bearing hole 6, a strain is generated in the cylinder head 2 in the lateral direction around the bearing hole 6; The bearing hole 6, which is formed to have a cross-sectional shape that takes this into consideration, becomes a substantially perfect circle when deformed by this strain. Therefore, the bearing function of the cylinder head 2 relative to the camshaft can be enhanced.

[Brief explanation of the drawing]

Fig. 1 is a side cross-sectional view showing an embodiment of the bearing member processing apparatus according to the present invention, Fig. 2 is a view taken along the line ■-■ in Fig. 1, and Fig. 3 is a view taken along the line -■ in Fig. 2. 4 is a sectional view taken along the line IV--IV in FIG. 2. 2... Cylinder head (bearing member) 4... Mounting table 6... Bearing hole 8... Boring bar (drilling tool) IO... Fine adjustment pin (
Processing center adjustment means) A...Processing center

Claims (1)

[Scope of Claims] 1) A processing method for forming a bearing hole in a bearing member, in which the bearing member is subjected to drilling at least twice by shifting the position of the processing core by a predetermined minute amount. A method of processing a bearing member, the method comprising forming two bearing holes. 2) A mounting table on which the bearing member is placed, a hole-drilling tool that drills a bearing hole in the horizontal direction by reciprocating in the direction of the machining center in the bearing member on the mounting table, and this hole-drilling tool moves forward. when and when to retreat,
A processing device for a bearing member, comprising processing center adjusting means for vertically shifting the relative position of the processing center of the hole-drilling tool and the bearing member on the mounting table by a predetermined minute amount.