JP2000271808A - Attachment having hydraulic intensifying mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an attachment supplying high pressure oil into only a small diameter cylinder regardless of other hydraulic system of a machine by using the small diameter cylinder for attaching/detaching an attachment main shaft tool. SOLUTION: An attachment is installed on an end surface of a main shaft head of a machine tool. A small diameter hydraulic cylinder 20 and a piston 21 is provided in order to remove a tool T equipped on a tip end of an attachment main shaft 5 internally provided in the attachment. A hydraulic booster 25 is provided on the attachment body 1, which intensifies pressure of pressure oil supplied in a rear chamber of the small diameter cylinder 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an attachment attached to a spindle head end face of a machining center, and more particularly to an attachment provided with a high-pressure hydraulic cylinder device for extracting a tool attached to a tip of the attachment spindle.

[0002]

2. Description of the Related Art In a machining center, various cutting tools are appropriately mounted on a regular spindle tip to perform various kinds of cutting, and various attachments are appropriately attached to a spindle head end face, and an interior attachment spindle is attached to each of these attachments. A cutting tool is attached to the tip to perform a wider range of cutting. The cutting ability when the attachment is used is determined by the rigidity of the gear for transmitting the clamping force and the driving force of the tool to the attachment main shaft, the main shaft in the attachment, and the rigidity of the attachment body supporting these gears / main shaft.

[0003] The rigidity of the attachment body increases as the distance A from the mounting surface of the attachment to the spindle head to the position at which the attached attachment spindle receives the cutting force, that is, the tip end of the attachment spindle, becomes shorter. However, a clamp force increasing mechanism is provided in the attachment main spindle in order to increase the tool clamping force to the tip of the attachment main spindle. Therefore, a relatively large-diameter cylinder is usually provided in the attachment as a hydraulic cylinder device for tool removal for reliably extracting a cutting tool strongly attached to the tip of the attachment main shaft, and the distance A becomes longer. The rigidity of the attachment body tended to be weak.

Therefore, as a conventional technique, the attachment is made compact by reducing the cylinder diameter, and the distance A from the mounting surface to the spindle head to the tip end of the attachment spindle is shortened. When a small-diameter cylinder is used, it is necessary to increase the pressure of the pressure oil supplied to the cylinder for tool removal, and all the pressure oil supplied to the hydraulic system of the machine has a high pressure.

[0005]

In the attachment described in the prior art, a small-diameter cylinder is provided as a hydraulic cylinder for extracting a tool attached to the tip of the spindle, and high-pressure oil is used. The entire system became high-pressure oil, and high-pressure oil was supplied to unnecessary parts. Therefore, there has been a problem that a hydraulic unit and piping parts for high-pressure oil must be used, which increases the cost. In addition, there is a problem that measures to prevent oil leakage from each location must be considered. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the related art, and has as its object to use a small-diameter cylinder for attaching and detaching a tool of an attachment main shaft, regardless of other hydraulic systems of the machine. It is an object of the present invention to provide an attachment that supplies high-pressure oil only to a cylinder.

[0006]

In order to achieve the above object, an attachment according to the present invention is attached to a spindle head end face of a machine tool and has an attachment / detachment mechanism for a tool attached to the attachment spindle. And a pressure increasing mechanism for increasing the oil pressure of the pressure oil supplied to the hydraulic cylinder device is provided in the attachment body.

In the above-mentioned attachment, high-pressure oil is supplied to a hydraulic cylinder device for attaching and detaching a tool of the attachment spindle by using a pressure oil pressure increasing mechanism. Therefore, the diameter of the tool extraction cylinder is reduced, and the spindle head of the attachment is mounted. When the rigidity of the attachment is strengthened by shortening the distance A from the mounting surface to the spindle tip position, the hydraulic pressure does not need to be increased in other hydraulic systems of the machine. They can be the same and do not increase costs. Further, no oil leakage is newly generated in a place where the high-pressure hydraulic pressure is not used.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the attachment of the present invention, and shows a state where a tool is gripped by an attachment main shaft provided inside the attachment.

An engaging portion 2 which is attached to the lower end of the spindle head of a machine tool (not shown) and is engaged and clamped is fixed to the upper end surface 1a of the main body 1 of the attachment. At the center position of the engaging portion 2, a transmission shaft 3 which is spline-fitted with a rotation drive shaft in a main shaft head (not shown) and receives rotation is vertically rotatably supported, and a first bevel gear 4 is provided at a lower end thereof. It has integrally.

At the lower part of the main body 1, an attachment main shaft 5 having a center line having an inclination angle of 45 ° with respect to the center line of the transmission shaft 3 is rotatably mounted with the tool mounting tip 5a facing downward. . A second bevel gear 6 meshing with the first bevel gear 4 is keyed to the attachment main shaft 5. At the center of the attachment main shaft 5, a slightly eccentric disk-shaped dog 7 is keyed while maintaining a rotational balance, and a sensor 8 for reading the eccentric position of the dog 7 is attached to the main body 1. ing.

By detecting the eccentric position of the dog 7 which rotates with the rotation of the attachment main shaft 5 and stopping the attachment main shaft 5 at a fixed position, the tool T mounted on the tip of the attachment main shaft 5 can be automatically changed. I'm running. An axial through-hole 5b is formed in the center of the attachment main shaft 5, and the tip of the through-hole 5b is formed in a taper hole 5c for mounting a tool. A collet 9 for gripping the pull stud Ta of the tool T mounted on the tapered hole 5c is provided in the through hole 5b following the tapered hole 5c, and an inner periphery for releasing the outer peripheral flange 9a of the tip tool gripping portion of the collet 9 is provided. A groove 5d is formed in the through hole 5b. Further, an intermediate clamp member 10 which engages with the collet 9 to open and close the collet 9 is provided behind the through hole 5b.

A rear portion of the intermediate clamp member 10 has a blind hole 10a formed in the center, and has a sleeve shape. A plurality of small holes 10c are formed in the sleeve-like portion 10b in the radial direction.
Is loosely fitted. Further, the cylindrical member 12 has its tip end stepped in the through hole 5b so as to cover the outer periphery of the sleeve-shaped portion 10b.
It is provided in a state where it is in contact with. A draw bar 13 is provided in the through hole 5b so as to be movable in the axial direction following the intermediate clamp member 10, and the front end 1 of the draw bar 13 is provided.
3a is loosely fitted in the blind hole 10a of the intermediate clamp member 10.

In the gripping state of the tool T shown in FIG. 1, the front end face 13b of the front end 13a of the draw bar 13 and the blind hole 10a
A predetermined gap is provided between the inner surface 10d and the inner surface 10d (FIG. 2). Also, the front end 13 of the drawbar 13
An outer peripheral groove 13c for dropping the steel ball 11 is cut in a. The outer circumferential groove 13c is set in such a positional relationship that the steel ball 11 starts to drop as soon as the draw bar 13 starts to move forward.
The outer peripheral dimension formed by all the steel balls 11 when they fall into c is configured to be smaller than the inner diameter of the cylindrical member 12.

Next, an intensifying mechanism for strongly attaching the tool T to the attachment main shaft 5 will be described with reference to FIG.

A tapered surface 13d which presses the steel ball 11 to the rear of the attachment main shaft 5 by a wedge action when the draw bar 13 retreats is formed on the tip side of the outer peripheral groove 13c of the draw bar 13.
Are formed. An inner tapered surface 12a is formed on the inner periphery of the cylindrical member 12 so as to come into contact with the distal end side of the attachment main shaft 5 of the steel ball 11 when the draw bar 13 moves backward. Therefore, when the draw bar 13 moves backward, the steel ball 1
First, the attachment main shaft 5 is formed by the tapered surface 13d.
At the same time as it is pushed radially outward.

When the steel ball 11 is pushed outward in the radial direction, it presses the tapered surface 12a in a direction perpendicular to the surface, and receives the reaction force of the component force in the shaft drilling direction due to the slope of the tapered surface 12a. Reference numeral 11 is pushed rearward of the attachment main shaft 5. That is, the steel ball 11 receives the combined force of the force pushed backward by the tapered surface 13d and the force pushed backward by the tapered surface 12a, and this combined force causes the rear inner surface of the small hole 10c of the intermediate clamp member 10 to move backward. It constitutes an intensifying mechanism of pushing.

As shown in FIG. 2, the positional relationship between the intermediate clamp member 10 and the rear end of the cylindrical member 12 is set such that the rear end surface of the cylindrical member 12 is located slightly behind by δ. A disc-shaped first spring receiving plate 14 is provided on the rear end surface of the cylindrical member 12. A second spring receiving plate 16 is attached to the rear portion of the draw bar 13 so that the position of the second spring receiving plate 16 can be adjusted by a nut member 15 screwed. The nut member 15 is supported by a donut-shaped support 17 provided in the through hole 5b so as to be concentric with the through hole 5b. A plurality of disc springs 18 are interposed between the first spring receiving plate 14 and the second spring receiving plate 16 to constantly urge the draw bar 13 in the backward direction.

A front end of a hydraulic cylinder 20 attached to a bracket 19 fixed to the main body 1 is loosely fitted to the final end of the through hole 5b. A piston 21 is provided in the hydraulic cylinder 20.
Is inserted so as to be movable in the axial direction, and the front piston rod 22 of the piston 21 contacts the rear end face of the draw bar 13 when the piston 21 advances, and is provided in a positional relationship of pushing the draw bar 13. A lock nut 24 for regulating the forward end position of the piston 21 is screwed to the rear piston rod 23 of the piston 21.

A hydraulic booster 25 (for example, HC-3 manufactured by Pioneer Machine Tool Co., Ltd.) for supplying high-pressure oil to the rear chamber of the hydraulic cylinder 20 is attached to the main body 1. A flow path 26 provided in the main body 1, the bracket 19, the hydraulic cylinder 20, and the like from the outlet.
An oil passage is formed so as to communicate with the rear chamber of the hydraulic cylinder 20 through the oil passage. An oil passage 27 is formed in the front chamber of the hydraulic cylinder 20 so that pressure oil of normal pressure that does not increase the pressure is supplied. A thin through hole 28 is formed in the axis of the piston 21, the front piston rod 22, and the rear piston rod 23, a thin through hole 29 is formed in the center of the draw bar 13, and a thin through hole 30 is formed in the center of the intermediate clamp member 10. With this arrangement, the tapered surface 5c for attachment of the tool of the attachment shaft 5 can be cleaned with air.

Next, a hydraulic circuit using the hydraulic booster 25 will be described with reference to FIG.

Normal pressure oil is sent from the pump P to the large-diameter cylinder 32 rear chamber of the hydraulic booster 25 via the direction control valve 31. The large diameter piston 33 of the large diameter cylinder 32 and the small diameter piston 35 of the small diameter cylinder 34 are integrally connected. Since the force applied to the large-diameter piston 33 at the normal pressure is transmitted to the small-diameter piston 35, the pressure is increased from the discharge port of the small-diameter cylinder 34 in inverse proportion to the ratio of the area of the large-diameter piston 33 to the area of the small-diameter piston 35. Pressure oil is sent out. This increased pressure oil is supplied to the rear chamber of the cylinder 20 attached to the attachment body 1, and the piston 21 moves forward with a large force.

Normal pressure oil is supplied to the rear chamber of the large-diameter cylinder 32 of the hydraulic booster 25, and when the large-diameter piston 33 advances, the oil in the front chamber of the large-diameter cylinder 32 is returned to the tank through the directional control valve 31. It is. At this time, the oil in the front chamber of the cylinder 20 is also returned to the tank through the directional control valve 31 because the piston 21 of the cylinder 20 also advances at the same time. Piston 2
In order to retract the hydraulic cylinder 1, the position of the directional control valve 31 is switched, and the normal pressure oil is supplied from the pump P via the directional control valve 31 to the front chamber of the thin cylinder 20 and the front chamber of the large-diameter cylinder 32 of the hydraulic booster 25. To supply. In the hydraulic booster 25, the large-diameter piston 33 retreats and the small-diameter piston 35 also retreats, so that the oil in the rear chamber of the cylinder 20 flows into the front chamber of the small-diameter cylinder 34. That is, the front indoor oil of the small-diameter cylinder 34 of the hydraulic booster 25 and the rear indoor oil of the cylinder 20 repeat the back and forth each time the hydraulic booster 25 operates. However, if the frequency of use increases, the check valve 3
The oil supply is performed sequentially through 6.

Next, the operation of this embodiment will be described.

When the tool T is completely inserted into the tool mounting tapered hole 5c of the attachment spindle 5, normal pressure oil is supplied to the front chamber of the cylinder 20, the piston 21 retreats, and the front end surface of the front piston rod 22 Moves away from the rear end face of the draw bar 13. The cylindrical member 12 is pushed by the disc spring 18 and is always pressed against the stepped portion 5d of the through hole 5 of the attachment main shaft 5 so that its position does not change. Therefore, the cylindrical member 12 is moved by the disc spring 18 via the second spring receiving plate 16 and the nut 15. Drawbar 1
3 is retracted.

The steel ball 11 which has fallen into the outer peripheral groove 13c due to the retreat of the front end portion 13a of the draw bar 13 moves radially outward, and the wedge surface of the tapered surface 13d and the inclination of the inner peripheral tapered surface 12a of the cylindrical member 12 are inclined. The intermediate clamp member 10 is retracted by the force increased by the surface. With this increased force, the collet 9 is pulled with a strong force by the pull stud Ta of the tool T.
And the tool T is strongly clamped to the main shaft 5. FIG. 1 shows the above state.

When the tool T is removed from the main shaft 5 after the completion of the cutting by the tool T, high-pressure oil from the hydraulic booster 25 is supplied to the rear chamber of the cylinder 20. The piston 21 advances and the front end face of the front piston rod 22 is
3, the drawbar 13 is further advanced against the disc spring 18. The steel ball 11 falls into the outer peripheral groove 13c, and the draw bar 13 further advances while the distal end surface contacts the inner surface 10d of the blind hole 10a of the intermediate clamp member 10.
By this advance, the intermediate clamp member 10 also advances, and the collet 9 is advanced, the flange 9a of the collet 9 escapes into the inner peripheral groove 5d, and the collet 9 is opened. Next, after the front end of the intermediate clamp member 10 contacts the rear end surface of the tool pull stud Ta, a strong pressing force of the piston 21 by the high-pressure oil causes
The tool T, which is strongly mounted, is caused to be pulled out from the main shaft 5 forward.

[0027]

Since the attachment of the present invention is constructed as described above, the following effects can be obtained.

In the attachment according to the first aspect of the present invention, high-pressure oil is supplied only to the hydraulic cylinder of the tool attachment / detachment mechanism of the attachment spindle using a hydraulic pressure increasing mechanism. Therefore, if the diameter of the tool extraction cylinder is made small and the distance from the attachment surface of the attachment to the spindle head to the spindle tip position is shortened to increase the rigidity of the attachment, the hydraulic pressure in other hydraulic systems of the machine Need not be raised, and can be operated at normal pressure. That is, in other hydraulic systems of the machine, the hydraulic units and piping parts can be the same as the conventional ones, so that the cost does not increase and there is no risk of newly generating oil leakage. In addition, since only a small amount of oil is at high pressure, heat generation can be minimized.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing an attachment of the present invention.

FIG. 2 is an enlarged explanatory view showing a force increasing mechanism of a tool clamp.

FIG. 3 is an explanatory diagram showing a circuit using a hydraulic pressure increasing mechanism.

[Explanation of symbols]

 5 Attachment spindle 20 Cylinder 21 Piston 25 Hydraulic booster T Tool

Claims (1)

[Claims] 1. A machine tool attached to a spindle head end face,
In an attachment having a tool attachment / detachment mechanism attached to the attachment spindle, a hydraulic cylinder device is provided as the tool attachment / detachment mechanism, and a pressure increasing mechanism for increasing the oil pressure of pressure oil supplied to the hydraulic cylinder device is provided in the attachment body. Attachment with a characteristic hydraulic pressure increase mechanism.