JPS59214545A - Copy machining device for bearing hole - Google Patents

Abstract

PURPOSE:To realize a hole with high precision and given surface roughness in a copy machining device for piston holes of internal-combustion engines or the like, by drilling a pin hole to taper with a single conic angle or with successive variation of angles toward the center of the piston. CONSTITUTION:A master cam 5 attached to a master cam holder 6 has on its inner wall the same taper as that of the piston pin hole 11a to be formed in the work 11. The master cam holder 6 is supported by means of a bearing 7, so that it can rotate freely around the axis of rotation of a boring tool 3. Therefore, with rotation of the main shaft 1, the boring tool attached to an eccentric device 2 also rotates, and is moved along the axis of the main shaft toward the work 11 by a work feed device. When the stylus 9 reaches a part of the master cam 5, it rotates in contact with the inner wall of the cam 5, and when the stylus 9 deviates in response to the cam 5, the cutter 4 also deviates, whereby the pin hole 11a is machined.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a bearing hole profiling device for machining a piston pin hole or the like of an internal combustion engine into a special shape.

The piston bore of an internal combustion engine is subjected to extremely high pressure during an engine explosion. Particularly in high-load applications, the piston d
Cracks often occur near the upper end of the inside of the bottle hole, but this is because the piston pin is bent in the axial direction of the bottle due to high combustion pressure, and this causes the bottle to be strongly pressed against the upper end of the inside of the bottle hole, causing strong stress concentration. Furthermore, as a result of this, the bottle is crushed in the direction of the piston movement, and as a result, the bottle pushes the bottle hole to expand, and tensile stress is generated at the inner upper end of the bottle hole.

Therefore, in order to alleviate the above-mentioned high stress, for example, the bottle hole should be enlarged very slightly toward the center of the piston, so that even if the piston pin is bent or crushed, the bottle will be pressed against the bottle hole. All that is needed is to relax and equalize the local stress concentration caused by the bottle and to prevent the bottle hole from being pushed wide by the bottle, but bearings with high surface pressure such as piston pin holes require high precision holes. The above method has not been used because a predetermined surface roughness is required and it must be processed at low cost.

In other words, since the amount by which the bottle hole is enlarged inward is extremely small and corresponds to the amount by which the bottle is crushed, it is difficult to perform processing using a numerical control device, especially for smooth finishing. It was impossible to do so.

Conventionally, measures have been taken to solve these problems, such as increasing the diameter of the piston pin or reducing the dimension between the piston bosses. There were problems in that the weight increased, the shape of the connecting rod, etc. had to be changed, and the cost also increased.

The present invention has been made based on the above-mentioned viewpoints, and its purpose is to form a bottle hole with a high taper so that the taper amount changes continuously toward the center of the piston. It is an object of the present invention to provide a bearing hole copy processing device that can process a bearing hole with high accuracy and a predetermined surface roughness at a low cost.

The gist of this is that a main shaft is rotatably supported, an eccentric device attached to the main shaft, a boring tool having a cutting tool at the tip and attached to the eccentric device, a cylindrical master cam having a stylus guide on its inner surface and rotatably supported substantially coaxially with the boring tool and separately from the main shaft;
A stylus fixed to the boring tool, one end of which is brought into contact with the stylus guide of the master cam, and a workpiece table supported movably relative to the main shaft in the direction of the main shaft, on which the workpiece is mounted. and a bearing hole tracing force device is configured by a machining feed device that moves the main shaft relative to the workpiece table and mask cam in the direction of the main shaft.

Hereinafter, the details of the present invention will be specifically explained with reference to the drawings.

The drawing is an explanatory view showing an embodiment of a bearing hole copying device according to the present invention.

In the figure, 1 is a main shaft that is rotatably supported so as to move forward and backward in the direction of the rotation axis, 2 is an eccentric device attached to the main shaft 1, 2a is a slit formed in the eccentric device 2, and 3
is a boring tool; 4 is a cutting tool attached to the tip of the boring tool 3; 5 is a mask cam supported substantially concentrically with the boring tool 3; 6 is a mask cam holder; 7 is a bearing; 8 is a mask cam including the bearing 7. 5 and a mask cam holder that holds the mask cam holder 6 and is fixed to the slide base or movably attached to the slide base; 9 is a stylus whose tip is pressed against the mask cam 5; 10 is a stylus that holds the boring tool 3 eccentrically; A bolt is attached to the device 2, 11 is a workpiece, ita is a piston pin hole, and 12 is a workpiece stand.

An eccentric device 2 is attached to the rotatably supported main shaft 1, and a cutting tool 4 is attached to the tip of the eccentric device 2.
A boring tool 3 with a stylus 9 attached thereto is also attached by a bolt IO.

The eccentric device 2 is formed with a sling 2a, and is configured to be able to eccentrically keep the center of the boring tool 3 parallel to the spindle center axis at all times.

The mask cam holder 6 has a mask cam 5 whose inner peripheral surface has the same taper shape (single or continuously changing taper) as the piston pin hole 11a formed in the workpiece 11.
is installed. Since this mask cam holder 6 is held via a bearing 7, it can freely rotate around the central axis of rotation of the boring tool 3.

The boring tool 3 mounted on the eccentric device 2 rotates as the main shaft 1 rotates, and is moved along the central axis of the main shaft 1 by a processing feeder (not shown). It is moved towards the workpiece 11.

When the stylus 9 reaches the mask cam 5, the stylus 9 rotates while contacting the inner peripheral wall of the mask cam 5 with appropriate contact pressure, but the stylus 9 and the cutting tool 4 are attached to the same boring tool 3. Since the stylus 9 is fixed, the stylus 9 is connected to the mask cam 5.
If the tool 4 is eccentric according to the shape of the mask cam 5, the cutting tool 4 will also be eccentric by the same amount, so a piston pin hole 11a corresponding to the shape of the mask cam 5 is formed in the workpiece 11.

Furthermore, since the mask cam 5 is rotatably supported by a bearing 7 via a mask cam holder 6,
The mask cam 5 and the stylus 9 can rotate freely due to the friction IQ force. For this reason, the contact pressure of the stylus 9 against the mask cam 5 is increased by adjusting the size of the slit 2a provided in the eccentric device 2, so that the stylus 9 is pressed against the mask cam 5 during processing and vibrations (chatter) etc. are caused. In addition to ensuring that machining is performed with high precision without
According to the contact pressure of the stylus 9, the mask cam 5
Since the stylus 9 rotates and the stylus 9 slides on the mask cam 5 only in the moving direction of the slide base, there is little wear on the tip of the stylus 9, and processing can be performed with stable accuracy for a long time.

Therefore, if the cutter 4 attached to the tip of the boring tool 3 is attached with a star and an eraser 9 so that they are on the same line in the circumferential direction of the boring tool 3, the diameter of the mask cam 5 will be increased, and the diameter of the mask cam 5 will be increased. Stylus 9 is eccentric device 2
It will be pushed up by As a result, the cutting tool 4 is also pushed up by the same amount as the stylus 9, so it is machined to be larger than the piston pin hole 11aG.On the other hand, if the diameter of the mask cam 5 is small, the stylus 9 will be pushed downward. Therefore, the piston pin hole tta is machined to be small.

That is, with this eccentricity j; the rest stylus 9 contacts the inner circumferential wall surface of the mask cam 5 with an appropriate contact pressure, and the cutting tool 4 moves according to the shape of the mask cam 5, so that the piston changes according to the shape of the mask cam 5. A pin hole 11a is thus formed.

Since the present invention is configured as described above, when using the bearing hole copy processing device according to the present invention, bearings with special shapes such as piston pin holes can be drilled with high accuracy and a predetermined surface roughness.
Moreover, it can be processed at low cost.

Note that the present invention is not limited to the above embodiments.

That is, for example, in this embodiment, the mask cam had a cylindrical shape, but it may also have a frame-like shape, or a slit may be provided in the portion corresponding to the cylindrical mask cam, and a star cam may be formed. The slit may move in the moving direction of the slide base while contacting the bottom surface of the slit, and the bottom surface of the slit throat may be shaped in accordance with the degree of taper of the piston pin hole shape. In this case, the stylus is caught on the side of the slit, causing the master holder to rotate. Further, in this embodiment, the cutting tool and the stylus were located in the same radial direction of the boring tool, but they may be located in opposite directions (180 degrees) on the same straight line. In this case, the chi/shape of the mask cam is opposite to that of the bottle hole. Furthermore, it is also possible to configure the main shaft etc. to only rotate and not move, but to move the workpiece table and the mask cam holder, and the shape and shape of the eccentric device, boring tool, mask cam and stylus, etc. The mounting, position, etc. can be freely changed in design within the scope of the object of the present invention, and the present invention encompasses all of them.

[Brief explanation of drawings]

The drawing is an explanatory view showing an embodiment of a bearing hole copying device according to the present invention. 1-----・-1--------------1--Main shaft 2----1-------1--Eccentric device 3 −−−−1・−−−−−−−−−1−−−−−−
Boring tool 4−・−−−1−−−−−−−−−−
−−−−−−Byte 5−−−−−−−−−−−−−−−
−−−−−−Master cam 6−−−−−−−−−−−−−
−− =−−−−−Master cam holder 7−−−− −−
−−−−−−−−−−−−Bearing 8−−−−−−−−
−−−−−−−−−−−−−−−−−−−−−−1−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−− Stylus 10−−−−−− ----------------Bolt 11---------------One workpiece 11
a ------------------Piston pin hole 12----------One workpiece table patent applicant
Izumi Jidosha Kogyo Co., Ltd. Agent (7524) Shotabe Mogami

Claims (1)

[Scope of Claims] A bearing hole profiling device comprising the components described in items a) to g) below. a) A rotatably supported main shaft. b) an eccentric device attached to said main shaft; C) A boring tool with a cutting tool on the outpost and mounted on the eccentric device. d) A cylindrical master cam having a stylus guide on its inner surface and rotatably supported substantially coaxially with the boring tool and separately from the main shaft. e) A stylus fixed to the boring tool and having one end abutted against the stylus guide of the master cam. f) A workpiece table on which a workpiece is mounted, which is supported so as to be movable relative to the main shaft in the direction of the main shaft. g) A processing feeder that moves the main shaft relative to the workpiece table and mask cam in the direction of the main shaft.