JPH0341283B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an expanding mandrel that presses the outer surface of a segment against a clamping surface of a workpiece.

For example, a segment is arranged around a conical tapered member, and by moving the member relative to the segment in the longitudinal axis direction, the segment is displaced in the radial direction and pressed against the clamping surface of the workpiece. The mandrel is already known. In this known mandrel, the segments are independent of each other. The drive of this known mandrel takes place via means specifically provided for this purpose.

This known mandrel has a number of drawbacks, the main ones of which are as follows.

- Generally complex in structure and therefore expensive.

- Being independent of each other, the segments must be relatively long to obtain the necessary cooperation for tightening.

- A separate rotational drive system for the mandrel must be provided.

The object of the present invention is to provide a mandrel that does not have the above-mentioned drawbacks and is particularly advantageous for mass production.

This object is achieved by the present invention, which comprises a body, a bush consisting of a plurality of segments, for tightening the workpiece by changing the diameter, and means for changing the diameter, the body being provided with The mandrel is provided with at least two radial projections in the forward portion of the body, and a notch is provided at the rear end of each of said segments, said notch cooperating with said projection to rotate the mandrel. This is achieved by the characteristic spreading mandrel.

The spreader mandrel of the invention also provides that the number of segments is equal to the number of protrusions and that the segments are connected to each other by bonding a thin layer of rubber or the like to the sides of the segments by hardening or gluing in a known manner. Also features.

Further features of the invention include a first cylindrical portion which fits at least partially into a corresponding recess formed in the adapter plate for the machine tool when the mandrel body is attached to the front end of the mandrel in a known manner; a second cylindrical part coaxial with the first cylindrical part; a third cylindrical part coaxial with the second cylindrical part and having the radial protrusion having exactly the same dimensions; a third cylindrical part coaxial with the third cylindrical part and forward; The fourth portion is tapered to the number of segments constituting the same number of segments, all of which have a notch on at least a portion of their rear end.

Each of the segments has notches that are arranged at equal intervals and interlock with the projection, and there is a slight operational play between the sides of each notch and each segment.

The height h of the protrusion is equal to the height H of the segment.
smaller than

Such an embodiment provides an appropriate stress distribution during processing.

The tightening means consists of a rod whose rear end is screwed into the actuating device, and the front end of this rod is fitted with a head which abuts the front end of the segment, the head being moved rearward by the actuating device by a distance approximately equal to j1. is energized and drives the bush while moving.
When the bush expands against the elastic action of an annular return spring and a thin layer of rubber or the like, the segments move longitudinally and press radially against the clamping surface of the workpiece.

That is, when tightening a workpiece, the bush expands in diameter due to the elastic action of an annular return spring provided in a circular groove formed in the thin layer and in the front surface of the bush so as to be inclined toward the mandrel axis. Since the return spring is fitted to the front of the bushing, the return spring is not affected by the outer diameter of the bushing.
The dimensions of the segments can thus be adapted to the bore diameter of the workpiece without disturbing the return spring.

The unclamping means consists of a plurality of rods extending through holes formed in a portion of the body and acting on the rear ends of the segments, each rod associated with a respective segment, the rods forming an integral part of the actuating device. actuated by the front face of the flange. Said actuating device moves forward to untighten the mandrel and at the same time drives the head and rod forward, pushing the segment forward and the bushing regaining its initial shape under the action of the return spring and the elastic thin layer. .

Each of the rods serving as a return button, which is a means of unfastening the workpiece, includes an annular pad such as rubber that is fitted into a radial groove formed in each rod in a hole formed in a portion of the mandrel body. . An annular gasket made of rubber or the like is fitted into a radial groove formed in each rod that acts as a return button, thereby preventing the rod from unintentionally protruding from its housing, that is, the hole formed in the mandrel body. can do.

The segments are made of a hard and almost inelastic material.

Other features and advantages of the mandrel according to the invention include:
It will become clear from the following description and associated drawings, which illustrate embodiments.

As shown in FIG. 1, a machine tool adapter table 10 is fixed to the machine tool by screws 11. At least a portion of the first cylindrical portion 1 ₁ of the mandrel body 1 is fitted into the center notch of the mandrel body 1 . A second cylindrical portion 1 ₂ following this first cylindrical portion 1 ₁
is coaxial with the first cylindrical portion 1 ₁ . The diameter of the second cylindrical portion 1 ₂ is smaller than the diameter of the first cylindrical portion 1 ₁ .
A third cylindrical portion 1 3 coaxially with the second cylindrical portion 1 ₂ and having a smaller diameter follows the second cylindrical portion 1 ₂ . As will be described later, a radial protrusion 1 ₄ that acts as a tooth for rotationally driving the mandrel is formed integrally with the third cylindrical portion 1 ₃ . The height h (Fig. 2) of this protruding part ₁₄ is the diameter of a circle corresponding to the length of the diameter of the third cylindrical part ₁₃ plus the height h, which is smaller than the diameter of the second cylindrical part ₁₂ . Set it so that A tapered portion ₁₅ follows the third cylindrical portion ₁₃ . In the illustrated embodiment, this tapered portion ₁₅ is conical. However, it does not depart from the scope of the present invention even if the tapered portion ₁₅ is formed into a truncated pyramid shape. By moving the bushing 2 fitted to this tapered portion ₁₅ to the left (top of Figure 1), the workpiece P can be tightened, and by moving it to the right (top of Figure 1), the workpiece P can be tightened. can be solved. Butsuyu 2
consists of the same number of segments as there are drive teeth ₁₄ . The segments 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ , 2 ₅ are connected to each other by a thin layer 3 made of rubber or the like which is adhered to the side surfaces of the segments by hardening or adhesion. The outer diameter of the bush 2 is the same over its entire length, there is no cut on the outer surface of the bush 2, the workpiece P is attached to the outer surface of the bush 2, and the workpiece P is tightened by crimping the outer surface and the hole of the workpiece P. It will be done. A return spring 4 is provided in the inclined groove 12 of the front surface 2f of the bush 2 in order to return the bush 2 when unfastening and to maintain the segment in a neutral position. The length of the bushing is set so that there is a play j1 between the front end of the bushing and the front end of the conical portion ₁₅ when the mandrel is untightened. As is clear from FIGS. 2 and 4, at the rear end of each segment there are notches 2 ₁ ′, 2 at regular intervals at the same time as the rotating driving teeth 1 ₄ of the mandrel.
₂ ′, 2 ₃ ′, 2 ₄ ′, and 2 ₅ ′ are provided. The rotation takes place in the direction of arrow f. There is a play a necessary for operation between the tooth ₁₅ and the rear surface of the cut. Thereby, in the case of mass production, the workpiece P can be tightened completely uniformly. The segments 2 ₁ , 2 ₂ , ... 2 ₅ are made of a hard, inelastic material, and therefore can be made of a material that is relatively inexpensive and that minimizes the wear of the segments. This is extremely advantageous for mass production of product P.

A center hole is formed in the main body 1 so that the rod 5 can slide in the longitudinal direction while closely contacting the wall of the center hole. The rod 5 has a head ₅₁ at its front end, and the rear surface of the head cooperates with the front end of the bush 2 to push the bush to the left (upward in FIG. 1) and clamp the workpiece P. The intermediate portion ₅₂ of the rod 5 can slide while remaining in close contact with the inner wall of the center hole of the main body 1. Rod 5
The rear end ₅₃ is screwed into an actuating means 7 having a flange ₇₁ movable in the central recess of the table 10 by the distance j3 necessary for tightening or unclamping the mandrel. The front surface of the flange ₇₁ cooperates with the rear end of the rod 6 inserted into holes arranged concentrically with the center holes formed in the cylindrical parts ₁₁ and ₁₂ of the main body 1, so that the front end of the rod 6 segment 2 ₁ , 2 ₂ ,
Act directly on the rear ends of 2 ₃ , 2 ₄ , and 2 ₅ to unfasten the mandrels as described in detail later. One rod is linked to each segment. A radial groove 13 is formed in each rod 6 in the portion of the hole penetrating the cylindrical portions 1 ₁ and 1 ₂ of the main body 1 that passes through the cylindrical portion 1 ₁ , and an annular packing 14 made of rubber or the like is formed in this groove. Insert. A stopper 8 is fixed to the main body 1 by a screw 9, and the workpiece P is accurately positioned with respect to the bush 2 by its front surface.

The workpiece P is tightened as follows.
The rod 5 is driven in the direction of the arrow _fs by means 7 which can be controlled by mechanical, hydraulic, electrical or the like.
Rod's head 5 ₁ also points button 2 with arrow f _s
Push in the direction of , until the play j1, the play j2 and the play j3 between the grooves 2 ₁ ', 2 ₂ ', . . . 2 ₅ ' and the drive teeth disappear. Play for tightening j1, j2 and j3
are almost the same, but setting it to j3j2j1 does not depart from the scope of the present invention, and the rod 6, which serves as a return button, is pressed at the rear. When the conical part ₁₅ of the main body 1 is moved in the direction of the arrow _fs while being in close contact with each other, the return spring 4 and the thin layer 3
The diameter of the bush increases due to the elastic action of the stopper 8, and the workpiece P is first gripped, positioned against the rear surface of the stopper 8, and finally completely tightened.
By thus moving the bush 2 in the direction of the arrow f _s , the drive tooth 1 ₄ moves between the segments 2 ₁ , 2 ₂ ,
2 ₃ , 2 ₄ , 2 ₅ cuts 2 ₁ ′, 2 ₂ ′, 2 ₃ ′, ... 2
₅ ′ and occlusal correctly. As the main body 1 rotates, the teeth ₁₄ drive the bush 2 and the workpiece P.

To untighten the mandrel, the control device moves the means 7 in the direction of the arrow f _d . Flange 7 ₁
Under the action of , the rod 6 moves to the right (in the direction of the arrow f _d ) by a distance approximately equal to the play j3. At the same time, the means 7 also move the rod 5 in the direction of the arrow f _d so that the head 5 ₁ is moved by a distance approximately equal to the play j 1 . The bush 2 with its front end released is pushed in the direction of the arrow f _d by the rod 6 until the plays j1 and j2 are completely restored.

Under the elastic action of the return spring 4 and the thin layer 3, the outer diameter of the bushing 2 again assumes its neutral value for release. The workpiece P that has been machined is removed, for example, by an automatic mechanism, and a new workpiece P is attached to the bush 2.

Various improvements and changes can be made without departing from the scope of the invention. For example, the workpiece P may be tightened and rotated not by the shaft hole but by the outer diameter.

Moreover, the cuts 2 ₁ , 2 ₂ , 2 ₃ , . . . may be configured to span two consecutive segments 2 ₁ , 2 ₂ , 2 ₃ , .

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of the expanding mandrel according to the present invention, FIG. 2 is an enlarged sectional view of the mandrel taken along the line A-A in FIG. 1, and FIG. 3 is an enlarged sectional view of the mandrel taken along the line B-B in FIG. FIG. 4 is an exploded view of the outside of the bushing, which consists of segments connected to each other by thin layers of rubber or the like. In the figure, 1: the main body of the spreading mandrel, 1 ₁ : the first
Cylindrical part, 1 ₂ : Second cylindrical part, 1 ₃ : Front part, 1
₄ : Radial protrusion, 1 ₅ : Tapered part, 2: Bush, 2 ₅ : Front surface, 2 ₁ , 2 ₂ , 2 ₃ , 2 ₄ , 2 ₅ ...
...: Segment, 2 ₁ ′, 2 ₂ ′, 2 ₃ ′, 2 ₄ ′, 2 ₅ ′
…
...: cut, 3: thin layer, 4: annular return spring, 6:
Rod, 12: Circular groove, 13: Radial groove, 1
4: Annular packing, a: play, P: workpiece.

Claims (1)

[Scope of Claims] 1. A body comprising a body, a bush consisting of a plurality of segments, which tightens a workpiece by changing the diameter, and means for changing the diameter, the body including a portion disposed at the front. In the spreading mandrel, the front part 1 ₃ of the main body 1 is provided with radial projections 1 ₄ of the same number as segments, and the segments 2 ₁ , 2 ₂ , 2
₃ , 2 ₄ , 2 ₅ ...... have notches 2 ₁ ',
2 ₂ ′, 2 ₃ ′, 2 ₄ ′, 2 ₅ ′ . The expanding mandrel is characterized in that the mandrel is adapted to engage and cooperate with the protrusion to rotate the mandrel. 2. When the mandrel body 1 is attached to the front end of the mandrel, the first cylindrical part 1 ₁ is at least partially fitted into a corresponding notch formed in the adapter plate 10 for the machine tool, and is coaxial with the first cylindrical part 1 ₁ . a second cylindrical portion 1 ₂ , a third cylindrical portion 1 ₂ having a radial protrusion 1 ₄ coaxially with the second cylindrical portion 1 2 and having exactly the same dimensions;
A cylindrical portion 1 ₃ , a fourth portion 1 ₅ which is coaxial with the third cylindrical portion 1 ₃ and tapers forward, and a main body which expands in diameter to tighten the workpiece and contracts in diameter to release the tightening. a bush 2 that is movable in the longitudinal axis direction of the mandrel while being in close contact with the tapered portion 1 ₅ of the mandrel;
An expanding mandrel according to claim 1, characterized in that: 3. Claims characterized in that the notches of the segments are arranged at equal intervals and interlock with the protrusion ₁₄ , and there is a slight operational play a between the sides of each notch and each segment. The spreading mandrel according to paragraph 2. 4 The height of the protrusion is the height H of the segment.
The expanding mandrel according to claim 3, characterized in that the expanding mandrel is smaller than . 5 When tightening the workpiece P, the bush 2 resists the elastic action of the annular return spring 4 provided in the thin layer 3 and the circular groove 12 formed in the front surface 2f of the bush 2 so as to be inclined toward the axis of the mandrel. The expanding mandrel according to claim 4, characterized in that the expanding mandrel expands in diameter. 6. Each of the rods 6, which act as a return button of the means for releasing the tightening of the workpiece P, is made of rubber fitted into a radial groove 13 formed in each of the rods 16 in the hole of the first cylindrical portion ₁₁ of the mandrel body 1. The spreading mandrel according to claim 5, characterized in that it includes an annular packing 14 such as.