JPS6035537Y2 - Drilling tool that maintains a constant depth - Google Patents

Description

[Detailed description of the invention] This invention relates to tools that require hole drilling to be maintained at a constant depth from one end surface of the workpiece, and is particularly applicable to high-speed, high-precision turning machine tools based on NC control. The most useful drilling is related to tools.

Conventionally, when machining a counterbore hole that requires a certain depth accuracy, such as an O-ring groove, the depth A to be cut into a workpiece 1 using a cutting blade 2 has been set at a high depth, as shown in Fig. 1. Accurate dimensions are required.

This is because when using O-rings, etc. as packing materials for hydraulic machines, if there is an error in the above depth A, there is a risk of serious defects such as oil leakage, and therefore the tolerance range for dimensional errors is limited. Currently, it is standardized to be constant.

Normally, the above-mentioned counterboring tool uses a machining center or a drilling machine, and is processed by NC control.
, set the position of the cutting edge by accurately measuring the distance B from the machining reference 3 to one end surface 1' of the workpiece, and then determine the cutting distance C according to the drawing. It is common to program the dimensions and input them into the control device to perform subsequent automatic operations, but when performing the above, if there is variation in the distance from the end face 1' to the processing reference 3 for each workpiece, Drilling the hole as it is has the disadvantage that the machined depth A varies.

To deal with the above problem, it is possible to continue the work while checking the distance B to the end face 1' for each workpiece, or to measure and check the depth after machining for each workpiece, but the operation is extremely cumbersome. However, it has the major drawback of requiring setup time and being inefficient.

The present invention has been developed in view of the above-mentioned problems, and is aimed at eliminating the various drawbacks caused by the conventional means and obtaining a high-speed, high-precision tool.

FIG. 3 is a perspective view showing the appearance of the drilling tool according to the present invention;
FIG. 4 shows its longitudinal sectional view.

In the figure, reference numeral 11 denotes a base holder, which is connected to the main shaft of a cutting machine main body (not shown) and rotates together with the main shaft.

A through hole 12 is bored in the base holder 11 , and a small diameter portion of a substantially cylindrical support tube 13 having a stepped portion is fitted into the through hole 12 . It is fixed with a set screw 14 from ''.

15 is an adjustment nut for adjusting the fit of the support cylinder 13.

Inside the support tube 13 is a sleeve 1 which is also made of a substantially cylindrical body.
6 is slidably inserted into the inner wall 13' of the support cylinder 13,
Moreover, the structure is such that the rotational force on the main shaft side is transmitted via the key 17.

Reference numeral 18 indicates a cutting blade of an end mill or the like that is fitted into the sleeve 16 and fixed with a set screw 19 provided at one end of the sleeve, and the tip of the set screw 19 is connected to the chamfered portion 18' of the cutting blade 18.
Press it against the

Further, the inner wall protrusion 16a of the sleeve 16 has a female thread 16b.
is engraved, and is screwed into one end of an adjustment bolt 20 inserted into the through hole 13'' of the support tube 13.

By adjusting the bolt head 20' of the adjusting bolt 20 from the base holder side with a screwdriver or a hexagonal wrench, the tip of the bolt protrudes from the cutting blade, and the protruding length of the cutting blade 18 can be adjusted.

In addition, if the axial thrust (cutting force) is small, cutting blade 1
8 is held from the side with a set screw 19, and the cutting blade 18 and adjustment bolt 20 are separated from each other without direct contact and used to adjust only the pressing force of the cutting blade 18 against the workpiece by the disc spring 21. good.

Further, a disc spring 21 is inserted between the inner wall stepped portion 13a of the support cylinder 13 and the inner wall stepped portion 16c of the sleeve 16, and the biasing force of the disc spring acts in a direction to separate the sleeve 16 from the base holder 11 side. are doing.

Note that there is a gap X between the sleeve 16 into which the disc spring 21 is inserted and the support tube 13, which is configured as an allowance for the cutting stroke.

Further, a housing 23 is attached to the front outer surface of the sleeve 16 via a bearing 22, and a stopper member 24 is further fixed to the front end thereof using a set screw 25.

A support member 24 is provided on the surface facing the workpiece side, and
A housing 23 integrally formed with the tip of the sleeve 16 via a bearing 22 is configured to move in the axial direction on the large diameter portion of the support tube 13 against the biasing force of the disc spring 21.

Incidentally, the housing 23 and the abutment member 24 may not be separate bodies as in this example, but may be constructed as an integral part.

The abutting member 24 has an inner wall 24' that serves as a through hole for inserting the cutting blade 18, and the sleeve is arranged so that the tip of the cutting blade 18 protrudes 2 minutes forward from the front end 24a of the corresponding member 24. Install it on 16.

Also, a notch 24'' is provided in a part of the front end 24a of the stopper member 24 in consideration of the discharge of chips.

With the above configuration, the sleeve 16, the cutting blade 18 connected thereto, the housing 23, and the support member 2
4 and are held in a so-called floating state with respect to the axial direction.

The operation of the drilling tool according to the present invention will be explained below.

When starting the cutting process, the protrusion length Z of the cutting blade 18 from the tip of the abutment member 24 is measured with a caliper or a dial gauge and set accurately.

Since the protrusion length 2 corresponds to the cutting depth for the workpiece 1, that is, the desired constant width A (FIG. 1),
Set accurately using another length measuring tool.

Next, the base holder 11 is rotated at high speed by rotational drive on the spindle side based on NC control, and the cutting blade 18 is attached to the workpiece 1 side.
approach and start cutting.

The rotational force of the main shaft is transmitted from the base holder 11 to the cutting blade 18 via the support tube 13 and the sleeve 16, and the target hole is drilled by the blade of an end mill or the like.

At this time, the housing 23 and the abutment member 24 integrated therewith are attached via the sleeve 16 and the bearing 22, so they are in a free state, and although some inertia rotation is involved, the rotation on the main shaft side is not possible. Don't respond.

When the cutting depth for the workpiece 1 reaches Z, the contact member 24
The front end surface 24a of the workpiece 1 comes into contact with the end surface 1' of the workpiece 1, and the cutting operation is stopped.

That is, even if the cutting blade 18 continues to rotate, the abutment member 24 functions as a stopper and causes the cutting blade 18 to rotate idly.

The rotation and movement of the base holder 11 is NC-controlled based on a preset program, and is set to be slightly overworked relative to the moving distance in the cutting direction with respect to the workpiece 1, that is, the cutting depth Z.

In the case described above, the tip of the cutting blade 18 enters into the workpiece for 2 minutes to finish drilling the target hole, and even after the stopper works and the cutting blade idles, the spindle remains in the fixed position in the Z direction. In this case, the cutting blade 18 does not stop and moves further into the workpiece 1.

At this time, the sleeve 16 presses the disc spring 21 against the biasing force of the disc spring 21 and slides inside the support cylinder 13 to the right in the drawing, and the cutting blade 18 connected to the sleeve 16, the housing 23, and the The member 24 also floats in the same direction,
Furthermore, with regard to the thrust in the axial direction, by deflecting the disc spring 21 in advance with the adjustment bolt 20 and setting a load corresponding to the thrust, it is possible to cope with a thrust in the direction of the main shaft that is more than necessary.

Thus, it operates to absorb the overwork distance.

The above operation can prevent the occurrence of insufficient cutting amount for the workpiece 1.

The gap X provided between the sleeve 16 and the support cylinder 13 is a gap for absorbing the above-mentioned overwork.

The present invention has the configuration and operation mode described in detail above, and by employing this device, the following advantages and effects in use can be achieved.

In other words, when drilling holes in a workpiece using normal NC control,
In the conventional method of setting machining standards, determining the distance B to one end of the workpiece, and the distance C when cutting, and then programming, the unavoidable minute errors that occur due to the accuracy of the machine tool and during operation. In particular, as the workpiece becomes smaller, the error percentage tends to increase.Furthermore, in the case of tools where the cutter is simply fixed to the base holder, the hole drilling depth must be adjusted to prevent overcutting. Although it would be necessary to set the depth slightly in advance and compensate for the insufficient cutting in a subsequent process, if the tool according to the present invention is equipped, all of the above problems can be solved.

In the case of the present invention, if the protrusion distance of the cutting blade is set accurately in advance, based on the set value, holes that maintain an unchanging constant depth can be continuously obtained in the member, and the holes are deep. There is no fear of a lack of quality.

In this invention, the rotation of the cutting blade does not respond to the abutting member that is integrated with the housing, which is provided via a bearing at the shaft end of the sleeve on the cutting blade edge side. The deflection of the tip of the cutting blade caused by the play between the parts can be prevented by the pressing force between the workpiece reference surface and the abutting member through the disc spring, and it also accurately contacts the end face of the workpiece to act as a stopper, and further prevents chips from the bearing. It is effective in providing protection.

The structure of the tool itself is relatively simple and easy to manufacture, and it can be used at a length that can be simply inserted and fixed into a conventional base holder, and does not require any operational skill, reducing cost, mass productivity, and
Preferred embodiments are obtained in all aspects of operability, and the present invention has the advantage of being applicable to turning machines based on NC control and various other ordinary machine tools.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams showing the principle of drilling a hole based on NC control, Figure 3 is a perspective view showing an embodiment of a tool for drilling a hole according to the present invention, and Figure 4 is a schematic diagram showing the implementation principle of the drilling tool according to the present invention. The hole of the invention is a longitudinal sectional view showing an embodiment of the tool. 11... Base holder, 12... Through hole, 13... Support cylinder, 14... Set screw, 15... Adjustment nut, 16...
Sleeve, 17...key, 18...cutting blade, 19...set screw, 20...adjustment bolt, 21...disc spring , 22...
Bearing, 23...Housing, 24...
...Batch member, 25... Set screw.

Claims (1)

[Scope of utility model registration request] A support cylinder 13 fitted and fixed to a base holder 11 which is connected to the main shaft and rotates; a sleeve 16 which is fitted into the support cylinder 13 so as to be slidable in the axial direction and which rotates together with the main shaft; 16; a housing 23 rotatably attached to the sleeve via a bearing 22 on the outer side of the cutting edge in the axial direction of the sleeve; and a cutting blade 18 protruding from the tip of the housing 23. In order to press and adjust the protrusion length of the sleeve 1, an adjustment bolt 20 is screwed into one end of the sleeve, and the support tube 13 and the sleeve 1 are connected to each other.
A drilling tool that maintains a constant depth and is characterized by comprising a spring material that biases a cutting blade inserted between the two holes in a protruding direction.