JP2009297885A - Spindle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently and surely supply sufficient air supply pressure in a method which does not interfere with a bearing structure of a rotary shaft. <P>SOLUTION: A spindle device 100 comprises: the rotary shaft 110 having an air supply passage 110a which opens from an air supply opening to its tip end by penetrating the inside; a holding mechanism 130 for releasing when the sir supply pressure supplied through the air supply passage 110a is applied; a connection body 141 having a tip end contact face 141s, wherein an air supply hole 141b having a tip end side opening facing to the air supply opening and a base end side opening at an opposite side is formed and axially penetrated, the tip end side opening is opened, and the tip end side opening is formed to be connected with the air supply opening when the tip end side opening is closely connected with a base end section of the rotary shaft; and an air supply inlet 142a communicating with the base end side opening. Air pressure cylinders 142, 143 for housing a connecting body at a moving-back and forth state are provided so as to make the tip end contact face of the connecting body bring into contact with the base end section 112 of the rotary shaft by being axially released at the tip end side. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spindle device in which a gripping mechanism that operates by supplying air pressure is provided at the tip of a rotating shaft, and more particularly to a spindle device that includes a supply air pressure supply means for supplying a supply air pressure to the gripping mechanism.

2. Description of the Related Art Conventionally, there is known a spindle device for attaching a gripping mechanism such as a chuck to the tip of a rotating shaft body that is pivotally supported by a bearing body and machining a tool or a work held by the gripping mechanism. In such a spindle device, there is a case where the gripping mechanism is operated with or without the supply air pressure. However, normally, the bearing surface is supplied from the outer periphery of the bearing body that supports the rotating shaft body to the inside of the rotating shaft body. The air pressure is supplied and the air supply pressure is transmitted to the gripping mechanism through the rotating shaft (see, for example, Patent Documents 1 and 2 below).
JP 2000-225505 A JP 2001-219302 A

  However, in the spindle device provided with the gripping mechanism, it is necessary to supply the supply air pressure from the outer peripheral portion of the bearing body. Therefore, when used in a clean room or the like, dust in the bearing portion leaks to the outside or the air supply path is There is a problem that it is difficult to efficiently supply a sufficient supply air pressure by passing through the bearing surface. In particular, when a fluid (gas) hydrostatic bearing or the like is used, there is a possibility that the supply / exhaust system of the bearing portion and the above-described supply passage communicate with each other to cause a pressure drop.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and an object thereof is to provide a spindle device that can efficiently and reliably supply a sufficient supply air pressure by a method that does not interfere with the bearing structure of the rotating shaft body. There is.

  In order to solve the above-mentioned problems, a spindle device of the present invention is rotatably provided with an air supply passage that is rotatably supported and penetrates the interior from an air supply opening provided at the base end in the axial direction and opens to the tip. A shaft body, a gripping mechanism attached to the tip of the rotary shaft body, which is released when a supply air pressure supplied through the air supply passage is applied, and grips when the supply air pressure is released; and the supply mechanism An air supply through hole provided with a distal end opening facing the air opening and a proximal end opening opposite to the air opening is formed penetrating in the axial direction, the distal end opening is opened, and a proximal end portion of the rotating shaft body A connecting body having a distal end abutting surface configured such that the distal end side opening is connected to the air supply opening when in close contact with the rotating shaft body, and disposed on the proximal end side in the axial direction with respect to the rotating shaft body And an air supply inlet communicating with the base end side opening on the base end side in the axial direction. The connecting body is accommodated so as to be able to advance and retreat in the axial direction so that the distal end abutting surface of the connecting body can be brought into contact with the proximal end portion of the rotating shaft body. And a pneumatic cylinder.

  According to the present invention, when a sufficient supply air pressure is applied to the base end side of the connection body through the air supply inlet of the pneumatic cylinder, the connection body moves to the front end side, and the front end abutment surface thereof is the rotation shaft body. Since the supply air passage hole of the connection body is connected to the supply passage of the rotating shaft body in contact with the base end portion, the supply air pressure is supplied from the supply air hole to the supply passage. When the supply air pressure is supplied through the air supply passage of the rotating shaft body, the gripping mechanism releases the gripped object. As described above, the connecting body is connected to the gripping mechanism by moving the connecting body in the axial direction of the rotating shaft body so that the supply air pressure can be supplied without using the bearing structure of the rotating shaft body. Can be supplied to the gripping mechanism, so that no gas leakage occurs and the gripping mechanism can be operated reliably. In this case, since the gripping mechanism is configured to grip when the supply air pressure is released and release when the supply air pressure is applied, the connection body is removed when the rotation driving state of the rotary shaft body is released. Since it only needs to be configured to connect the rotating shaft body and supply the supply air pressure, the connection body and the rotating shaft body can be reliably connected.

  In one aspect of the present invention, the connection body includes a base that is open at the proximal end side, has a larger area than the distal contact surface, and receives a supply air pressure supplied from the supply air inlet. An end-side pressure receiving surface is provided at an edge on the opposite side in the axial direction with respect to the tip contact surface. According to this, since the base-end-side pressure receiving surface of the connection body has a larger area than the tip contact surface, the rotating shaft body of the connection body due to the supply air pressure even if the upstream and downstream pressures of the connection body are close to each other. Since the pressing force against the base end portion of the gas is not lost, the operation of the connection body is not hindered, and the connection state between the air supply hole and the air supply passage is reliably maintained. Therefore, it is possible to efficiently supply a sufficient supply air pressure, and it is possible to reliably perform the connection operation between the rotating shaft body and the connection body by the supply air pressure itself. Further, since the area of the tip contact surface is small, even if the connecting body comes into contact with the rotating rotating shaft body, the effect of the rotational force on the connecting body (to the seal portion between the connecting body and the pneumatic cylinder) , Etc.) is reduced.

  In another aspect of the present invention, the connecting body has an axial line between a distal end side portion having the distal end abutting surface and a proximal end portion having the proximal end pressure receiving surface and having a larger diameter than the distal end side portion. The pneumatic cylinder is configured to have a stepped shape in a direction, and extends inward from the periphery of the pneumatic cylinder, and is disposed around the distal end portion and disposed at the distal end side of the proximal end portion. And an elastic member that is disposed between the inner projecting portion and the connection body and biases the connection body toward the proximal end in the axial direction. According to this, the connection body has a stepped shape having a small-diameter distal end portion and a large-diameter proximal end portion, and the inner overhanging portion of the pneumatic cylinder is disposed around the distal end portion and the base. The elastic member is disposed between the inner projecting portion and the connecting body, and the elastic member biases the connecting body toward the base end side in the axial direction. A stable urging force can be applied in a direction away from the rotating shaft.

  Hereinafter, an embodiment of a spindle device according to the present invention will be described in detail with reference to FIGS. 1 and 2. FIG. 1 is a schematic longitudinal sectional view showing the entire spindle device of the present embodiment, and FIG. 2 is an enlarged view of a range A surrounded by a one-dot chain line in FIG.

  As shown in FIG. 1, the spindle device 100 has a straight cylindrical shape as a whole, and a rotating shaft body 110 is accommodated therein, and is rotatably supported by a cylindrical bearing body 120. A gripping mechanism 130 is attached to the tip (upper end in the figure) 111 of the rotating shaft 110, and the gripping mechanism 130 operates with a supply air pressure described later. Specifically, the grip part 132 moves with respect to the fixed part 131 depending on the presence or absence of the supply air pressure, and thereby, an object to be gripped such as a work W or a tool (hereinafter simply referred to as a work W) can be attached and detached. Configured as follows. That is, when the supply air pressure is applied, the gripping part 132 moves relative to the fixed part 131 to release the work W, and when the supply air pressure is released, the gripping part 132 returns to fix the work W. The Furthermore, a rotation drive unit for rotating the rotary shaft 110 is provided on the base end side (downward in the drawing) of the bearing body 120, and this rotation drive unit is constituted by an electric motor 150 in the illustrated example. The electric motor 150 includes a stator 151, a rotor 152, and a rotational position sensor 153. The stator 151 is fixed to the housing, the rotor 152 is fixed to a portion near the base end of the rotating shaft 120, and the stator 151 and the rotor 152 are mutually connected. Are opposed to each other in the radial direction.

  The bearing body 120 includes a cylindrical first bearing member 121 that covers the outer periphery of the rotating shaft 110, a second bearing member 122 that is fitted and fixed to the distal end side of the first bearing member 121, and a first bearing member 121. And a third bearing member 123 fitted and fixed to the base end side. An annular pressure chamber 120a and a slot-like throttle 120b are formed in the fitting portions of these three bearing members, respectively, and the throttle 120b opens to the bearing surface facing the outer peripheral surface of the rotary shaft 110, and the rotary shaft body A hydrostatic air bearing constituting the 110 radial bearing is formed. Here, a gas such as compressed air is supplied to the pressure chamber 120a through the air supply path 101, and is supplied to the bearing gap through the throttle 120b. Although this bearing structure constitutes a gas bearing, a fluid bearing such as oil may be used as long as it is a fluid bearing.

  Further, the bearing body 120 is provided with a thrust bearing portion 124 fitted and fixed to the second bearing member 122 by one or a plurality of members. The thrust bearing portion 124 faces the rotary bearing body 110 in the axial direction. A diaphragm 120c is provided. The throttle 120c ejects the gas supplied from the air supply path 101 in the axial direction, and supports the rotary shaft 110 in the axial direction. The interior of the bearing body 120 communicates with the exhaust path 102, and the gas supplied to the bearing gap via the throttles 120b and 120c is exhausted through the exhaust path 102.

  The rotary shaft 110 is provided with an air supply path 110a penetrating in the axial direction, and an air supply opening, which is an opening on the base end side of the air supply path 110a, is opened at the center of the base end portion 112. A base end face 112a is formed. The base end face 112a is configured to be flat. A supply air pressure introduction mechanism 140 is provided further on the base end side of the base end portion 112 of the rotating shaft 110. The supply air pressure introducing mechanism 140 includes a connecting body 141 that faces the base end surface 112a, a housing member 142 that houses the connecting body 141 so as to be slidable in the axial direction, and a holding member that is fitted and fixed to the housing member 142. A member 143 is provided.

  The housing member 142 and the holding member 143 constitute a pneumatic cylinder, and this pneumatic cylinder opens to the front end side in the axial direction, and is opened to the internal space S of the rotation drive unit. The housing member 142 has an air supply inlet 142a formed on the base end side of the connecting body 141, and the supply air pressure is supplied into the pneumatic cylinder through the air supply inlet 142a. Further, the holding member 143 is formed with an inner overhanging portion 143a projecting inward beyond the cylinder inner wall of the housing member 142, and an opening 143b toward the tip end side in the axial direction of the cylinder portion is formed inside the inner overhanging portion 143a. Is provided. The holding member 143 has a function of holding the connection body 141 (and an elastic member 144 described later) in the cylinder portion by the inner overhanging portion 143a.

  The connection body 141 has a distal end contact surface 141s facing the base end surface 112a with a slight gap G at the distal end. The distal end connection surface 141s is configured to be flat, and the connection body 141 moves to the proximal end side. At this time, it comes into close contact with the base end face 112a. Thereby, the supply air pressure can be reliably transmitted from the connecting body 141 to the rotating shaft body 110. The connecting body 141 includes a distal end side portion 141X having the distal end contact surface 141s and a proximal end side portion 141Y slidably disposed inside the pneumatic cylinder. The distal end side portion 141X is a base end portion. The end portion 141 </ b> Y is configured to have a smaller diameter, and thus the connection body 141 has a stepped columnar shape as a whole. As a result, the area of the base end pressure receiving surface 141t facing the base end side in the axial direction of the base end side portion 141Y is made larger than the front end contact surface 141s facing the front end side in the axial direction of the front end side portion 141X. The In addition, in order to receive the supply air pressure from the supply air introduction port 142a more efficiently, a recess 141d that directly communicates with the supply air introduction port 142a is formed in the base end pressure receiving surface 141t, and the supply air is supplied by the recess 141d. The supply air pressure introduced from the inlet 142a is quickly applied to the connection body 141, and the initial speed of the connection body 141 is increased. The bottom area of the recess 141d is larger than the area of the tip contact surface 141s.

  Further, the connecting body 141 is provided with an air supply through hole 141a penetrating in the axial direction. The air supply through hole 141a has a distal end opening at the center of the distal end contact surface 141s and the proximal end side pressure receiving pressure. A proximal end opening that opens at the center of the surface 141t. The connecting body 141 (the base end side portion 141Y) is formed with an annular concave groove 141b that opens toward the distal end in the axial direction, and an elastic member 144 made of a coil spring is accommodated in the concave groove 141b. The elastic member 144 is disposed between the bottom of the concave groove 141b of the connection body 141 and the inner overhanging portion 143a of the holding member 143, and the connection body 141 is located on the proximal end side in the axial direction with respect to the pneumatic cylinder. Energized.

  As shown in FIG. 2, a guide ring 145a slidably contacting the inner wall of the pneumatic cylinder, a seal ring 145b such as an O-ring, and a ring-shaped spring material 145c are mounted on the outer periphery of the proximal end portion 141Y of the connecting body 141. In addition, airtightness and slidability between the pneumatic cylinder and the connecting body 141 are ensured.

  The internal space S of the rotation drive unit communicates with the exhaust path 102, and as a result, the front end side in the axial direction of the pneumatic cylinder is indirectly opened to a low pressure space (external space). The internal space S may be configured to communicate directly with the outside through a gap or an opening. Further, it is preferable that the gap G between the rotating shaft body 110 and the connecting body 141 is as small as possible so that they do not come into contact with each other in order to reduce the required operation stroke of the connecting body 141 to ensure a reliable operation and to make it compact.

  Note that the gripping mechanism 130 described above is a known diaphragm chuck (when a predetermined supply pressure is not applied, a gripping portion such as a chuck claw grips an object to be gripped such as the workpiece W, and the diaphragm is applied by applying a predetermined supply pressure. And a grip portion connected to the diaphragm is configured to release an object to be gripped), and others having a pneumatic cylinder operated by the above-described supply pressure, etc. If it is available, it can be easily obtained and manufactured.

  In the spindle device 100 configured as described above, when a supply air pressure is supplied by introducing a gas such as compressed air from the air supply inlet 142a, the force due to the air pressure on the distal end side of the connection body 141 and the air pressure on the proximal end side are supplied. The base-side pressure-receiving surface 141t is pressed due to the difference in force due to the force, and the tip-side contact surface 141s of the connection body 141 comes into contact with and comes into close contact with the base-end surface 112a of the base end portion 112 of the rotating shaft 110. The air supply hole 141a and the air supply passage 110a of the rotating shaft 110 are connected. The supply air pressure is supplied to the supply passage 110a of the rotating shaft 110 through the supply passage 141a of the connection body 141. At this time, since the base-side pressure receiving surface 141t has a larger area than the tip contact surface 141s, the air pressure between the base end surface 112a of the rotating shaft 110 and the tip contact surface 141s is temporarily supplied in the presence of the supply air pressure. Even when the pressure rises close to the atmospheric pressure, the connection body 141 is reliably pressed against the rotary shaft body 110 and the above connection state is maintained. Thus, the supply air pressure is reliably supplied to the gripping mechanism 130 through the air supply passage 110a of the rotating shaft 110, and the gripping mechanism 130 operates by the supply air pressure.

  Further, the connecting operation of the connecting body 141 to the base end portion 112 of the rotating shaft body 110 may be performed after the rotation driving to the rotating shaft body 110 is stopped, but depending on the situation, the rotation of the rotating shaft body 110 does not stop. It is also conceivable that the connecting body 141 operates at a later time. In this case, since the area of the tip contact surface 141s that contacts the base end surface 112a of the rotating shaft 110 is small, even if the connecting member 141 contacts the rotating shaft 110, the degree of transmission of the rotational force is increased. Therefore, the influence on the connecting body 141, for example, the rotational force that rotates with the rotating shaft 110 is given to the connecting body 141, so that the seal portions 145a, 145b, between the connecting body 141 and the pneumatic cylinder are provided. The load on 145c is reduced.

  In the case of the illustrated example, when the rotary shaft body 110 is driven to rotate, the supply air pressure from the air supply inlet 142a is lowered, so that the rotary shaft body 110 and the connection body 141 are separated by the elastic force of the elastic member 144. Yes. At this time, since the atmospheric pressure supplied to the gripping mechanism 130 is also low, the workpiece W is held between the fixed portion 131 and the gripping portion 132 (gripping state). When the rotation of the rotating shaft 110 stops, a sufficient supply air pressure is supplied from the air supply inlet 142a. As described above, the connecting body 141 comes into contact with the rotating shaft 110, and the pressure supplied to the gripping mechanism 130 increases. Therefore, the gripping part 132 moves and the workpiece W is released, and the gripper 132 can be detached from the gripping operation part 130.

  In the present embodiment, the base end surface 112a of the rotating shaft body 110 and the tip contact surface 141s of the connecting body 141 are formed flat and can be in close contact with each other. Since it is difficult for gas to leak from between the bodies 141, the supply air pressure can be reliably supplied to the gripping mechanism 130.

  Further, since the connecting body 141 is urged by the elastic member 144 in a direction away from the rotating shaft body 110, the connecting body 141 contacts the rotating shaft body 110 only by reducing or stopping the supply air pressure. Thus, the rotating shaft 110 is prevented from rotating while being kept.

  Note that the spindle device of the present invention is not limited to the illustrated examples described above, and it is needless to say that various modifications can be made without departing from the scope of the present invention. For example, in the above embodiment, a rotation drive unit (drive motor 150) is incorporated in the spindle device itself. However, the rotation drive unit is provided outside, and the rotary shaft 110 is configured to be driven to rotate by an external driving force. Also good. In the above embodiment, the rotary shaft 110 is rotatably supported by a gas bearing (hydrostatic air bearing) constituted by the bearing portion 120. However, the rotary shaft body 110 is not limited to the gas bearing and is supported by various bearing structures. It doesn't matter.

1 is a schematic longitudinal sectional view showing the overall configuration of a spindle device according to an embodiment of the present invention. It is an enlarged view of the range A enclosed with the dashed-dotted line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Spindle apparatus, 110 ... Rotating shaft body, 110a ... Supply air path, 111 ... Tip, 112 ... Base end part, 112a ... Base end surface, 120 ... Bearing body, 130 ... Operating part, 140 ... Supply air pressure introducing mechanism, 141 ... Connector, 141X ... tip side portion, 141s ... tip contact surface, 141Y ... base end side portion, 141t ... base end side pressure receiving surface, 142 ... housing member, 142a ... air supply inlet, 143 ... holding member, 144 ... Elastic member, W ... Workpiece

Claims (3)

A rotating shaft body provided with an air supply passage rotatably supported and penetrating from the air supply opening provided at the base end in the axial direction to open to the distal end;
A gripping mechanism that is attached to the tip of the rotating shaft body and that is released when a supply air pressure supplied through the air supply passage is applied and that holds when the supply air pressure is released;
An air supply through hole provided with a front end side opening facing the air supply opening and a base end side opening opposite to the air supply opening is formed penetrating in the axial direction, the front end side opening is opened, and a base of the rotating shaft body is formed. The distal end side opening is configured to be connected to the air supply opening when in close contact with the end portion, and is disposed on the proximal end side in the axial direction with respect to the rotating shaft body Connected body,
An air supply inlet that communicates with the base end opening is provided on the base end side in the axial direction, and the front end abutting surface of the connection body is opened to the front end side in the axial direction so that the base end of the rotary shaft body A pneumatic cylinder that accommodates the connection body so as to be capable of advancing and retreating in the axial direction so as to be able to contact the end portion;
A spindle apparatus comprising:   The connection body has an opening at the base end side, has an area larger than the front end contact surface, and has a base end side pressure receiving surface that receives a supply air pressure supplied from the air supply inlet. The spindle device according to claim 1, wherein the spindle device is provided at an edge opposite to the surface in the axial direction. The connecting body is configured in a stepped shape having a distal end side portion provided with the distal end abutting surface and a proximal end side portion provided with the proximal end pressure receiving surface and having a larger diameter than the distal end side portion in the axial direction. ,
The pneumatic cylinder is provided with an inner projecting portion that projects inward from the periphery, is disposed around the distal end portion, and is disposed on the distal end side of the proximal end portion.
The spindle apparatus according to claim 3, further comprising an elastic member that is disposed between the inner projecting portion and the connection body and biases the connection body toward a base end side in the axial direction.

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