JP2016175172A - Inner surface machining tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a boring tool capable of adopting an air cylinder while keeping machining accuracy.SOLUTION: A boring tool 10 is attached with a blade tool 32 on a columnar body portion 11, makes the blade tool 11 project and retract from an outer peripheral surface of the body portion 11 by a blade tool extruding mechanism 30 provided on the body portion 11, and cuts an inner surface of a bore by a projecting blade tool 32. The boring tool 10 is equipped with a blade tool movement suppressing mechanism 40 suppressing the movement of the blade tool 32 in a retracting direction, with cutting resistance acted on the blade tool 32.EFFECT: By the blade movement suppressing mechanism, the movement of the blade tool can be suppressed, and machining accuracy can be finely kept. The movement of the blade tool is limited, so that an air cylinder can be adopted as a drive portion.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an inner surface machining tool for cutting an inner surface of a bore with a cutting tool.

For example, the bore of the cylinder block is cut with a boring tool.
A boring tool is known in which a cutting tool is attached to a cylindrical main body, the cutting tool is provided on the main body so that the cutting tool protrudes from the outer peripheral surface of the main body, and the inner surface of the bore is cut with the protruding cutting tool. (For example, refer to Patent Document 1 (FIG. 1).)

  As shown in FIG. 1 of Patent Document 1, a shaft (66) is passed through a spindle shaft (24) (the numbers in parentheses indicate the reference numerals described in Patent Document 1. The same applies hereinafter). 66) is moved in the axial direction by a servo motor (22). As the shaft (66) moves, the grindstone (36) at the tip moves in the radial direction.

As shown in FIG. 1 of Patent Document 1, the rotational motion of the servo motor (22) is converted into linear motion by the ball screw (90).
Since the ball screw (90) has high transmission efficiency, it has an advantage that the model number of the servo motor (22) can be lowered. On the other hand, since the ball screw (90) is a precision mechanism, it is expensive and poor in durability against impact.

Therefore, an alternative to an air cylinder that is inexpensive and easy to handle has been studied.
Since the air contained in the air cylinder is a compressible fluid, it has an advantage that the piston moves backward and absorbs an impact when an external force exceeding a certain level is applied to the blade.

On the other hand, since the cutting tool moves in conjunction with the retraction of the piston, it becomes difficult to maintain the machining accuracy.
However, while an inexpensive boring tool is required, a structure capable of adopting an air cylinder while maintaining processing accuracy is required.

JP 2007-313619 A

  An object of the present invention is to provide an inner surface machining tool that can employ an air cylinder while maintaining machining accuracy.

According to the first aspect of the present invention, a blade is attached to a columnar body, the blade is pushed out from an outer peripheral surface of the body by a blade pushing mechanism provided in the body, and the protruding blade is cylindrical. In an internal machining tool that cuts the internal surface,
A cutting tool movement suppression mechanism that suppresses the cutting tool from moving in the sinking direction with a cutting force acting on the cutting tool is provided.

In the invention according to claim 2, the blade pushing mechanism includes a taper shaft built in the main body portion so as to be movable in the axial direction, a drive unit for moving the taper shaft in the axial direction, and a taper built in the main body portion radially. A rod that moves in a radial direction on a shaft,
The cutting tool movement suppression mechanism is a centrifugal brake that is provided at the tip of the taper shaft and that slides against a member on the main body side to exert a braking action.

  In the invention according to claim 3, the centrifugal brake includes a disc attached to the tip of the taper shaft, an arm attached to the disc in a swingable manner, a weight portion provided at the tip of the arm, and the weight It consists of the member of the main-body part side which a part slidably contacts.

  In the invention according to claim 4, the cylindrical member is attached to the tip of the main body, the centrifugal brake is accommodated in the cylindrical member, and the member on the main body side where the weight portion is in sliding contact is the cylindrical member. The inner peripheral surface is a rough surface.

In the invention which concerns on Claim 1, the movement of a blade tool can be suppressed by a blade tool movement suppression mechanism, and processing precision can be maintained favorable. Since the movement of the cutting tool is limited, an air cylinder can be employed as the drive unit.
Therefore, according to the present invention, an inner surface machining tool capable of adopting an air cylinder while maintaining machining accuracy is provided.

In the invention which concerns on Claim 2, a cutter movement suppression mechanism is a centrifugal brake which is provided in the front-end | tip of a taper axis | shaft, and slidably contacts with the member by the side of a main-body part, and exhibits a braking action. When the boring tool is rotated at a high speed, the centrifugal brake exhibits a braking action and connects the tapered shaft to the main body. As a result, the movement of the taper shaft is suppressed, and the movement of the blade is limited.
Since the centrifugal brake is provided in the vicinity of the cutting tool, the movement of the cutting tool can be effectively suppressed.

  In the invention according to claim 3, the centrifugal brake includes an arm, a weight part, and a member on the main body part side in which the weight part is in sliding contact. Centrifugal brakes have a simple structure and do not need to supply electric energy from the outside.

  In the invention which concerns on Claim 4, a cylinder member is attached to the front-end | tip of a main-body part, and the internal peripheral surface of a cylinder member is made into the rough surface. Due to the rough surface, the braking force of the centrifugal brake can be further increased.

It is sectional drawing of the boring tool which concerns on this invention. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 1. It is an effect | action figure of a centrifugal brake. It is a principle figure of the centrifugal brake of another form.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

  As shown in FIG. 1, a boring tool 10 as an inner surface processing tool includes a cylindrical main body 12 having a hollow portion 11 in the center, a stepped sleeve 13 accommodated in the hollow portion 11 of the main body portion 12, A first piston 15 fitted to the large diameter portion 14 of the stepped sleeve 13, and a second piston that extends forward from the first piston 15 in the axial direction and serves as a piston rod and is fitted to the small diameter portion 16 of the stepped sleeve 13. The piston 17, the third piston 18 accommodated in the hollow portion 11, the spring 19 and spring receiver 21 that are accommodated in the hollow portion 11 and urge the third piston 18 toward the distal end surface of the stepped sleeve 13, and the spring receiver A cylindrical member 22 that is attached to the tip of the main body 12 while supporting 21, and a piston rod 23 that extends from the third piston 18 so as to penetrate the cylindrical member 22. The taper shaft 24, the push rods 25, 25 that are slidably attached to the cylindrical member 22, extend in the radial direction, and are pushed out by the taper shaft 24, the cutting tool movement suppression mechanism 40 provided at the tip of the piston rod 23, and the cylinder And a lid 26 for closing the tip opening of the member 22.

An air passage 27 that sends compressed air to the back surface of the first piston 15 is provided at the base of the main body 12. The closed space between the second piston 17 and the third piston 18 is filled with oil 28.
When compressed air is sent through the air passage 27, the first piston 15 moves forward, and the second piston 17 moves forward together with the first piston 15. Then, the third piston 18 is pushed through the oil 28, and the taper shaft 24 moves forward together with the piston rod 23. When the taper shaft 24 moves forward, the push rods 25, 25 are pushed outward in the diameter.

  In the present embodiment, the drive unit 20 that moves the taper shaft 24 in the axial direction includes the third piston 18, the oil 28, the first and second pistons 15 and 17, and the air passage 27. Since the pressure receiving area of the first piston 15 is larger than the second piston 17, axial force can be earned even with compressed air having a pressure lower than the hydraulic pressure. Since the oil 28 is an incompressible fluid, the position of the third piston 18 can be accurately maintained.

  However, the drive unit 20 may be only an air cylinder or only a hydraulic cylinder. However, when only the air cylinder is used, the working medium is a compressive fluid, so that the position of the piston is likely to change, and the position accuracy may be lowered.

In the case of only the hydraulic cylinder, the positional accuracy is good, but the response is difficult, and the moving speed of the piston is slow.
In this respect, according to the present embodiment, since the compressed air with good responsiveness and the oil with good positional accuracy are used, the responsiveness and positional accuracy are improved.

As shown in FIG. 2, a plurality of (six in this example) roughing cutting tools 31 and a plurality (six in this example) of finishing tools 32 are alternately arranged on the cylindrical main body 12. Each push rod 25 is disposed below the finishing blade 32. The cutting tools 31 and 32 may be grinding wheels.
When the taper shaft 24 moves to the front side of the drawing, the push rod 25 moves in the radial direction, and the pushed finishing blade 32 is brought into a projecting state by the push rod 25.

  That is, the push rod 25, the taper shaft 24, and the drive unit 20 shown in FIG.

  As shown in FIG. 3, the cutting tool movement suppression mechanism 40 is, for example, a centrifugal brake. The centrifugal brake 40 as a cutting tool movement restraining mechanism includes a disc 41 attached to the tip of the piston rod 23 (or the taper shaft 24), an arm 42 attached to the disc 41 so as to be swingable, and the arm 42. Are formed of a torsion spring 43 that biases in the closing direction, a weight portion 44 integrally formed at the tip of the arm 42, and an inner peripheral surface 45 of the cylindrical member 22.

When the disc 41 and the cylinder member 22 rotate at a high speed in the counterclockwise direction in the drawing, centrifugal force is generated, and the weight portion 44 moves radially outward against the torsion spring 43.
Then, as shown in FIG. 4A, the weight portion 44 comes into contact with the inner peripheral surface 45 of the cylindrical member 22.
As shown in FIG. 4B, a frictional force is generated between the weight portion 44 and the cylindrical member 22 when the weight portion 44 hits the inner peripheral surface 45 of the cylindrical member 22. As a result, the axial movement of the taper shaft 24 is suppressed.

  In addition, it is good to provide the connection part 47 of the disk 41 and the arm 42 in the rotation direction upstream with respect to the rotation direction of a tool, and to provide the weight part 44 in the rotation direction downstream. Then, the centrifugal force can be used effectively and the brake can be applied reliably.

Preferably, the inner peripheral surface 45 of the cylindrical member 22 is a rough surface. By making the surface rough, the friction coefficient increases and the friction force can be increased.
In FIG. 1, when the taper shaft 24 is advanced and the finish cutting tool 32 protrudes from the main body portion 12 and the bore of the workpiece is cut (ground), a large force is applied to the finishing tool 32 due to cutting resistance. Join.

  It is possible to prevent the finishing blade 32 from moving in the sinking direction to some extent in the presence of the oil 28. However, when receiving a force more than that, there is a concern that the first piston 15 moves backward and the finishing blade 32 moves in the sunk direction.

Next, a modified example of the centrifugal brake 40 will be described.
As shown in FIG. 5A, the centrifugal brake 40B includes a disk 51 supported by a piston rod (FIG. 1, reference numeral 23) and a brake rotor 52 attached to the disk 51. In this example, the disc 51 and the brake rotor 52 are separated, but may be integrated.

  The brake rotor 52 includes a cylindrical base portion 53 fitted to the disk 51, and a weight portion 44 connected to the cylindrical base portion 53 via one coupling portion 47 and surrounding the cylindrical base portion 53 over almost the entire circumference. . The weight portion 44 and the cylindrical base portion 53 are divided by an annular groove 54 except for the coupling portion 47. The weight portion 44 is cut by a radiation groove 55 extending from the annular groove 54 side.

  The weight portion 44 can be easily obtained by cutting the annular groove 54 and the radiation groove 55 into one metal disk or resin disk, and is inexpensive. The weight portion 44 can also be manufactured by resin molding, and if it is resin molding, the annular groove 54 and the radiation groove 55 can be formed in the injection mold holder, so that the manufacturing cost can be further reduced.

  When turned along the arrow, the radial groove 55 expands in a wedge shape. As a result, the weight portion 44 moves radially outward and is in sliding contact with the cylindrical member (reference numeral 22 in FIG. 3).

  The centrifugal brake 40C shown in FIG. 5 (b) is different from the centrifugal brake 40B in that there are a plurality of coupling portions 47 (two in this example), and the others are the same as the centrifugal brake 40B. The detailed description is omitted using the reference numerals.

The centrifugal brakes 40B and 40C shown in FIGS. 5A and 5B have a simpler structure and are less expensive than the centrifugal brake 40 shown in FIG.
In addition, if a centrifugal brake is a mechanism which can exhibit a braking action using a centrifugal action, a structure and a form will be arbitrary.

In the present invention, the cutting tool movement suppression mechanism 40 is activated during cutting to suppress the backward movement of the taper shaft 24, so there is no concern that the finishing cutting tool 32 moves in the sinking direction.
Therefore, it can be said that the operation of an inexpensive air cylinder has become possible.

  The cutting tool movement restraining mechanism 40 may be a mechanism that causes a stop pin to protrude and retract from the main body 12 to the tapered shaft 24 in addition to the centrifugal brake. In short, it is possible to limit the axial movement of the tapered shaft 24 when necessary. Any form and structure can be used as long as the mechanism can be used.

Further, the boring tool 10 desirably includes both the roughing cutting tool 31 and the finishing cutting tool 32, but may include only the finishing cutting tool 32.
In the embodiment, the boring tool is disclosed, but a honing tool using a grinding wheel as a cutting tool may be used.

  The present invention is suitable for a boring tool for cutting a bore of an engine cylinder.

  DESCRIPTION OF SYMBOLS 10 ... Internal-surface processing tool (boring tool), 11 ... Hollow part, 20 ... Drive part, 22 ... Main part side member (tubular member), 24 ... Taper shaft, 25 ... Push rod, 30 ... Cutting tool extrusion mechanism, 32 ... Cutting tool (finishing tool), 40, 40B, 40C ... Cutting tool movement suppression mechanism (centrifugal brake), 41 ... Disc, 42 ... Arm, 43 ... Torsion spring, 44 ... Weight part, 45 ... Inner circumferential surface of cylindrical member , 47...

Claims (4)

In an internal machining tool that attaches a cutting tool to a cylindrical main body part, causes the cutting tool to protrude from the outer peripheral surface of the main body part by a cutting tool pushing mechanism provided on the main body part, and cuts the inner surface of the cylinder with the protruding tool. ,
An inner surface processing tool comprising a cutting tool movement suppression mechanism that suppresses movement of the cutting tool in a sinking direction with a cutting force acting on the cutting tool. The blade pushing mechanism includes a taper shaft built in the main body portion so as to be movable in the axial direction, a drive portion for moving the taper shaft in the axial direction, and a radial built-in shape in the main body portion with the taper shaft. And a rod that moves to
2. The inner surface machining tool according to claim 1, wherein the cutting tool movement suppression mechanism is a centrifugal brake that is provided at a tip end of the taper shaft and that slides on a member on the main body portion side to exert a braking action.   The centrifugal brake includes a disc attached to the tip of the taper shaft, an arm swingably attached to the disc, a weight provided at the tip of the arm, and the body in which the weight is in sliding contact. The inner surface machining tool according to claim 2, comprising a part-side member.   A cylindrical member is attached to the tip of the main body, the centrifugal brake is housed in the cylindrical member, and the member on the main body side where the weight portion is in sliding contact is the cylindrical member, and the inner peripheral surface of the cylindrical member The inner surface machining tool according to claim 3, wherein a rough surface is provided.

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