JPH0724505U - Spindle device - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the size and weight of equipment and extend the service life of bearings that support the spindle. [Structure] A tapered projection 15 is formed on the outer peripheral surface of the main shaft 2 on the rear end side.
To provide. A hydraulic cylinder 161 is arranged on the outer peripheral surface side of the main shaft 2 on the circumference thereof, and the hydraulic cylinder 161 is installed such that one end of the opening faces the tapered protrusion 15. A tapered portion 18 is provided at the tip of a piston 17 that can slide in the hydraulic cylinder 161, and the tapered portion 18 is formed so as to be able to contact the tapered protrusion 15. Due to the contact between the tapered portion 18 and the tapered protrusion 15, a wedge effect is produced at the contact portion, and even with a small contact force, the reaction force of the disc spring 7 acting on the bearing via the main shaft 2 (when the ejector rod 5 is pressed). Therefore, the piston 17 and the hydraulic cylinder 16 may be small in size, and only a small contact force is transmitted to the bearing 3 via the main shaft 2.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spindle device in which a tool can be replaced by an ATC, and is particularly intended to reduce the size and weight of the spindle device and extend the life of a bearing that supports the spindle.

[0002]

[Prior art]

 Conventionally, a spindle device capable of tool exchange by ATC has a cylindrical spindle 2 in a casing 1 as shown in FIG. 4, and the spindle 2 is rotatably supported by a bearing 3, and Tool fixing means is disposed on the inner peripheral surface side.

The tool fixing means is composed of an ejector rod 5, a drawbar portion (see reference numeral 6 in FIG. 1), a biasing means such as a pan 7, and a pressing means 8. The ejector rod 5 is attached to the main shaft 2. It is slidable along.

The drawbar portion (see reference numeral 6 in FIG. 2) is provided on the tip side of the ejector rod 5, and is opened and closed by sliding the ejector rod 5 to clamp and unclamp the tool T, and the disc spring 7 Urges the ejector rod 5 in the axial direction of the main shaft 2 (the direction indicated by the arrow in the figure) to set the drawbar portion to the normally closed state, that is, the clamped state.

The pressing means 8 is composed of a pressing piston 9 located on the extension line of the ejector rod 5 and a hydraulic cylinder 10 that accommodates this, and the pressing piston 9 slides in the direction shown by the arrow in the figure. Then, the piston rod 9a of the pressing piston 9 presses the rear end of the ejector rod 5 against the urging force of the plate spring 7 to set the drawbar portion to the open state, that is, the unclamped state.

When setting such an unclamping state, the reaction force of the disc spring 7 is continuously applied to the bearing 3 via the main shaft 2 from when the piston rod 9a starts to press the rear end of the ejector rod 5. It acts directly and shortens the life of the bearing 3. Therefore, in this type of spindle device, the following mechanism is adopted for the purpose of protecting the bearing 3.

In this spindle device, another second hydraulic cylinder 11 is provided outside the hydraulic cylinder 10 (hereinafter referred to as the first hydraulic cylinder), and the inside of the second hydraulic cylinder 11 as described above is provided. The first hydraulic cylinder 10 is slidably provided, and the first hydraulic cylinder 10 is formed with a large diameter piston 12 slidable in the second hydraulic cylinder 11 and integrally formed therewith. It is configured so that it can be engaged with the engaging protrusion 2a provided on the outer peripheral surface of the rear end of the main shaft 2 via the engaged protrusion 12a.

Then, when the pressing piston 9 slides in the direction shown by the arrow in the figure, and the piston rod 9 a tries to press the rear end of the ejector rod 5, the first hydraulic cylinder 10 moves in the opposite direction. In a direction (direction indicated by an arrow in the figure), and the sliding causes the engaging projections 12a and 2a to come into contact with each other and engage with each other.

With this engagement, the reaction force of the disc spring 7 acting on the bearing 3 via the main shaft 2 while the piston rod 9a is pressing the rear end of the ejector rod 5 is canceled.

[0010]

[Problems to be solved by the device]

 However, in the conventional spindle device as described above, it is possible to sufficiently cancel the extra force during unclamping, that is, the reaction force of the disc spring 7 acting on the bearing 3 via the spindle 2. In order to do so, the diameter of the second hydraulic cylinder 10 must be increased, which makes the equipment heavy and large.

Moreover, it is extremely difficult to bring the engaging projections 12a and 2a into contact with each other at the same time that the piston rod 9a comes into contact with the rear end of the ejector rod 5, and even if the contact timing is slightly deviated. Before the piston rod 9a and the ejector rod 5 come into contact with each other, the engaging projections 12a and 2a come into contact with each other, and unnecessary force due to this contact is applied to the bearing 3 via the main shaft 2 or the engaging projection 12a. , 2a come into contact with each other before the piston rod 9a and the ejector rod 5 come into contact with each other, and as a result, the reaction force of the disc spring 7 acts on the bearing 3 via the main shaft 2, resulting in a problem. Since an excessive force is momentarily applied to the bearing 3, there is a problem that the life of the bearing 3 is shortened.

The present invention has been made in view of the above circumstances, and an object thereof is to reduce the size and weight of a device and extend the life of a bearing that supports a spindle.

[0013]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a cylindrical main shaft rotatably supported by bearings, and a tool fixing means arranged on the inner peripheral surface side of the main shaft. However, the ejector rod that can slide along the main shaft, the drawbar part that opens and closes by sliding the ejector rod to clamp and unclamp the tool, and the ejector rod that is biased in the axial direction of the main shaft keeps the drawbar part closed at all times. In the main spindle device comprising the biasing means for setting the state and the pushing means for pushing the ejector rod against the biasing force of the biasing means to set the drawbar portion to the open state, the rear end side of the spindle A taper protrusion integrally provided on the outer peripheral surface, a cylinder located on the circumference of the main shaft and having one opening end facing the taper protrusion, and a cylinder slidably housed in the cylinder. The piston provided with a tapered portion that can come into contact with the tapered protrusion and the piston movement control means that moves the piston in advance until the tapered portion and the tapered protrusion contact each other before the pressing means presses the ejector rod. The feature is that it is provided.

[0014]

[Action]

 According to this invention, a wedge effect is generated in the contact portion between the taper portion and the taper protrusion portion, and even with a small contact force, the reaction force of the urging means acting on the bearing through the main shaft (when the ejector rod is pressed, (What happens) can be sufficiently canceled.

Further, according to the present invention, the taper portion and the taper projection portion are in contact with each other before the pressing means presses the ejector rod. However, even in such a case, such a small contact force as described above is applied. It is only transmitted from the piston to the main shaft via the taper part and taper projection part, and the unnecessary force applied to the bearing via the main shaft is reduced as much as possible.

[0016]

【Example】

 An embodiment of a spindle device according to the present invention will be described in detail below with reference to FIGS.

A basic structure of the main shaft device, for example, a cylindrical main shaft 2 is rotatably supported by a bearing 3 in a casing 1 as shown in FIG. 1 to FIG. A tool fixing means is disposed on the circumferential surface side, and the tool fixing means is composed of an ejector rod 5, a drawbar portion 6, biasing means such as a disc spring 7, and a pressing means 8 and the like. Therefore, the same members as those are given the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 3, this main spindle device is provided with a taper protrusion 15 integrally on the outer peripheral surface of the main spindle 2 at the rear end side, and on the outer peripheral surface of the main spindle 2, three taper projections are formed on the circumference thereof. A cylinder block 16 provided with a hydraulic cylinder 161 is provided, the cylinder block 16 is fixed to the rear flange 1a of the casing 1, and one end of the opening of the hydraulic cylinder 161 opposes the taper protrusion 15. It is installed in. The other end of the opening of the hydraulic cylinder 161 is closed by the end block 16a.

The piston 17 is housed in the hydraulic cylinder 161, and the piston 17 is provided with a taper portion 18 at its tip, and the taper portion 18 is a taper protrusion of the spindle 2 when the piston 17 advances toward the spindle 2. It is formed so as to be able to contact the portion 15.

An annular cutout recess is formed on the outer peripheral surface of the piston 17, and the space partitioned by this cutout recess and the inner wall of the hydraulic cylinder 161 is provided as hydraulic working chambers a and b.

An unclamping hydraulic pressure supply path 18 for advancing the pressing piston 9 of the pressing means 8 to the ejector rod 5 side is connected to one hydraulic working chamber a, and the other hydraulic working chamber b is pressed by the unclamping hydraulic pressure supply passage 18. A clamp hydraulic pressure supply path 19 for retracting the piston 9 to the original position is connected.

When the pressing piston 9 moves forward to the ejector rod 5 side by the hydraulic pressure from the unclamping hydraulic pressure supply passage 18, a part of the hydraulic pressure is supplied to the one hydraulic working chamber a, and the pressing force is increased. Before the piston rod 9a of the piston 9 presses the rear end of the ejector rod 5, the piston 17 advances in advance toward the main shaft 2 side, and the taper portion 18 of the piston 17 comes into contact with the taper projection 15 of the main shaft 2. Movement control of the piston 17 is performed.

When the pressing piston 9 of the pressing means 8 retracts to its original position by the hydraulic pressure from the clamping hydraulic pressure supply path 19, a part of the hydraulic pressure is supplied to the other hydraulic working chamber b, which causes the piston to move. 17 is also retracted to the original position, and the movement control of the piston 17 is performed so as to release the contact between the tapered portion 18 of the piston 17 and the tapered protrusion 15 of the main shaft 2.

The piston 17 is provided with a flattening portion 181 (a slip key may be used) for preventing rotation, and the piston rod 9a and the ejector rod 5 are not provided when the tool is changed (the piston rod 9a is an ejector). Except when pressing the rear end of the rod 5), it is separated by an appropriate gap G, and the gap G is set to be larger than the gap between the tapered portion 18 and the tapered protrusion 15.

Next, the operation of the spindle device configured as described above will be described with reference to FIGS. 1 to 3.

According to this spindle device, when the tool change command is received, the pressure piston 9 starts to move forward to the ejector rod 5 side due to the hydraulic pressure from the unclamping hydraulic pressure supply path 18, and at this time, a part of the hydraulic pressure. Is supplied to the hydraulic working chamber a, whereby the piston 17 also starts to advance to the main shaft 2 side.

At this time, since the gap G between the piston rod 9a and the ejector rod 5 is larger than the gap between the taper portion 18 and the taper projection portion 15, the taper portion 18 of the piston 17 and the taper projection portion 15 of the main shaft 2 are first The piston rod 9a of the pressing piston 9 and the ejector rod 5 come into contact with each other later.

That is, before the piston rod 9 a of the pressing piston 9 presses the ejector rod 5, the piston 17 moves in advance until the tapered portion 18 comes into contact with the tapered protrusion 15.

After that, when the piston rod 9a starts to press the ejector rod 5 against the biasing force of the disc spring 7, the ejector rod 5 slides, and the disc spring 7 bends in response to the slide, and the drawbar portion 6 is released. Is set to the open state, and the existing tool T is discharged to the ATC (not shown) side at the tip of the ejector rod 5.

By the way, when the ejector rod 5 is pressed, the reaction force of the disc spring 7 tries to act on the bearing 3 via the main shaft 2, but such an extra force causes contact between the taper portion 18 and the taper projection portion 15. It escapes from the portion through the piston 17 and the cylinder block 16 to the casing 1 side and is absorbed.

Further, when the taper portion 18 comes into contact with the taper projection portion 15, a wedge effect is produced at the contact portion. Therefore, even with a small contact force, the reaction force of the disc spring 7 acting on the bearing 3 via the main shaft 2 can be sufficiently canceled.

When a different tool is newly supplied from the ATC side (not shown) to the tip side of the spindle 2, instead of the tool T that has been unclamped and discharged as described above, the clamping hydraulic pressure supply passage The pressure piston 9 and the ejector rod 5 retreat to their original positions by the hydraulic pressure from 19 and the biasing force of the disc spring 7. At this time, a part of the hydraulic pressure is supplied to the hydraulic pressure working chamber b, whereby the piston 17 also retracts to its original position.

When the ejector rod 5 is retracted to its original position in this way, the drawbar portion 6 is set to the closed state, a new tool is clamped, and the tool exchange is completed.

Therefore, in the spindle device of this embodiment, a wedge effect is generated in the contact portion between the tapered portion of the piston and the tapered projection portion of the spindle, whereby a small contact force acts on the bearing via the spindle. Since the reaction force of the disc spring (which occurs when the ejector rod is pressed) can be sufficiently canceled, a large piston or cylinder that generates a large contact force is unnecessary, and a small piston and cylinder are sufficient. .

Further, according to this device, the taper portion and the taper projection portion come into contact with each other before the piston rod presses the rear end of the ejector rod. However, even in such a case, the small contact force as described above is used. Is transmitted from the piston to the main shaft via the tapered portion and the tapered protrusion, the extra force applied to the bearing via the main shaft is reduced as much as possible, and the life of the bearing is extended.

In the above embodiment, three hydraulic cylinders are provided on the circumference of the main shaft, but the number of these hydraulic cylinders can be appropriately changed, and an air cylinder may be used instead of the hydraulic cylinder.

[0037]

[Effect of device]

 In this invention, the cylinder is arranged on the circumference of the spindle as described above, and the piston in the cylinder is configured to come into contact with the spindle through the tapered portion and the tapered protrusion, so that the contact portion is wedged. As a result, even with a small contact force, the reaction force of the biasing means acting on the bearing through the main shaft (which occurs when the ejector rod is pressed) can be sufficiently canceled, and therefore the piston and The cylinder can be small, and the device can be made smaller and lighter.

Further, according to the present invention, the taper portion and the taper projection portion come into contact with each other before the pressing means presses the ejector rod, but even in such a case, the small contact force as described above is exerted from the piston. Since it is only transmitted to the main shaft via the tapered portion and the tapered protrusion, the extra force applied to the bearing via the main shaft is reduced as much as possible, which has the effect of extending the life of the bearing.

[Brief description of drawings]

FIG. 1 is an external view of a spindle device according to the present invention.

FIG. 2 is a sectional view of part A in FIG.

FIG. 3 is a sectional view of part B in FIG.

FIG. 4 is a sectional view showing a main part of a conventional spindle device.

[Explanation of symbols]

 2 main shaft 3 bearing 5 ejector rod 6 drawbar portion 7 disc spring (biasing means) 8 pressing means 15 taper projection 16 cylinder block 17 piston 18 taper 161 hydraulic cylinder

Claims (1)

[Scope of utility model registration request] 1. A cylindrical main shaft rotatably supported by a bearing, and a tool fixing means arranged on the inner peripheral surface side of the main shaft, wherein the tool fixing means is slidable along the main shaft. An ejector rod, a drawbar portion that opens and closes by sliding the ejector rod to clamp and unclamp the tool, and a biasing means that biases the ejector rod in the axial direction of the main shaft to set the drawbar portion to a normally closed state, A main spindle device comprising a pressing means for pressing the ejector rod to set the drawbar portion in an open state against the urging force of the urging means, wherein a taper projection portion integrally provided on the outer peripheral surface of the main spindle at the rear end side is provided. A cylinder positioned on the circumference of the main shaft and having one end of the opening facing the tapered protrusion, and a tetor slidably accommodated in the cylinder and capable of contacting the tapered protrusion. A piston provided with a path portion, the spindle device characterized by said pressing means is provided with a piston moving means for moving the piston until it contacts the advance the tapered portion and the tapered protrusion before pressing the ejector rod.