JPH0512496Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The invention is used in the technical field of fixing annular shaft parts on shafts, and in particular, the invention is used in the technical field of fixing annular shaft parts on shafts, and in particular, the invention is used in the technical field of fixing annular shaft parts on shafts. It also relates to a device that can be easily fixed.

(Prior Art and Problems) There are cases where it is required to fix a shaft component on a shaft at right angles to the axis with high precision. For example, when fixing parts such as bearings to the main shaft of a machine tool, conventionally a nut is used at a threaded portion on the shaft with a spacer or the like interposed therebetween, or a so-called stepped sleeve is used.

First, when fixing a screw using a nut, it is difficult to achieve precision on the thread surface, especially on the female thread surface. Therefore, no matter how accurate the flatness of the fixed end surface of the nut is, the center line and end surface of the screw This is due to the fact that the perpendicularity to the nut is not good, and the clearance at the threaded part is relatively large, so the nut is tightened at an angle, resulting in a difference in the tightening force on both sides of the center line. This causes bending stress on the shaft, making it impossible to ensure the accuracy of the center of the main shaft.

Next is the stepped sleeve, which has a stepped inner diameter that matches the step with a slight diameter difference on the shaft, and an annular groove formed in the step, and is shrink-fitted to the step on the shaft. When the temperature has cooled to room temperature, oil is injected under high pressure into the annular groove of the step to form an oil film on the stepped surfaces on both sides of the annular groove, allowing for axial movement. shall be. In this state, pressing force is applied to the sleeve, and after confirming that the sleeve has contacted the shaft component, the oil pressure is released. Then, the oil film disappears and the shaft component is firmly fixed at the above position. The shape of such a stepped sleeve is generally cylindrical, and the inner diameter surface and end surface can be manufactured with extremely high precision.This high precision directly applies to the fixing precision of the shaft parts, solving the problem of screw fixation mentioned above. be done.
However, the stepped sleeve has the following problems in terms of workability and cost.

Because the sleeve was originally inserted using a shrink fit method,
Prior to insertion, heating to approximately 150°C is required.

After shrink-fitting and insertion, the next work (oil injection, pressing work, etc.) cannot be performed until the sleeve, the shaft and other annular parts whose temperature has risen as a result of this, have cooled down to room temperature.

Normally, work is done with the shaft vertically, but
Some of the oil injected into the annular groove will pass through the fitting surface and flow out from the bottom end of the sleeve, so if the work is not done quickly, the leaked oil will enter the bearings, etc. located directly below. There is a risk of

While one hydraulic pump forms an oil film on the fitting portion, another hydraulic pump or the like applies pressing force to the sleeve, making it difficult for one person to do the work.

When fixing, the amount of movement of the stepped sleeve is
Since the distance is approximately several tens of micrometers, it is necessary to confirm the movement using a dial indicator, etc.

Further, although the purpose is not to fix the shaft components in the axial direction as described above, there is a known friction shaft joint that is made of a combination of a thick outer sleeve and a thin inner sleeve that fit into each other on a tapered surface.
This shaft joint has a hydraulic chamber between the inner and outer sleeves on the small-diameter end, and an oil film is formed on the tapered surface where the two sleeves come into contact to press the outer sleeve toward the large-diameter side, and after the hydraulic pressure is released, the inner sleeve Although it has some similarities to the stepped sleeve described above, it does not have a structure that can abut and fix the shaft component. In addition, the hydraulic chamber of this shaft joint is filled with oil even after the shafts are connected, and even if this is applied to the main shaft of a machine tool, if there are any air bubbles in the hydraulic chamber, This causes unbalance during rotation,
On the contrary, this results in a loss of rotational accuracy.

In addition, machining the inner diameter step of the shaft and the stepped sleeve requires high precision and a large number of man-hours, resulting in high costs and requires a high level of machining technology.

(Means for Solving the Problems) The present invention solves the problems of the above-mentioned conventional devices and provides a device that can accurately fix annular shaft parts with extremely simple work. The purpose is to

In order to achieve the above object, the present invention includes a thick outer sleeve having a tapered inner diameter surface and a thin inner sleeve having the same tapered outer diameter surface as the inner diameter surface of the outer sleeve. the outer sleeve has an annular stepped portion on the inner diameter of the small inner diameter end, the diameter of which is larger than the diameter of the extended surface of the tapered surface, and which is open at the small inner diameter end;
An oil hole is provided to press oil in from the outside, and the annular space between the small outer diameter end of the inner sleeve and the inner diameter surface of the stepped part of the outer sleeve is sealed and hydraulic pressure is applied inward in the axial direction. A piston body forming a chamber is disposed, and the piston body is slid axially inwardly to open the hydraulic chamber by a pressing member attached to a fixed member fixed to the small diameter end of the inner sleeve. It is possible to reduce the volume, and when the inner sleeve is in its normal assembly position into the outer sleeve, the large outer diameter end is closer to the large inner diameter end of the outer sleeve, and the smaller outer diameter end is closer to the above fixed position. each protruding axially from the member.

(Function) The procedure for fixing the shaft component according to the present invention having the above structure is as follows.

First, the inner sleeve is loosely inserted into the outer sleeve, and the piston body is placed in the annular space between the two.
Furthermore, a fixing member is attached to the inner sleeve to prepare it as an integrated unit.

Such unitized inner and outer sleeves, etc.
The inner sleeve is assembled onto the shaft so that the large-diameter end surface thereof comes into contact with the annular component to be fixed on the shaft.

Next, the small-diameter end face of the inner sleeve is pressed against the annular part by a force parallel to the axis using appropriate means and maintained in that state.

Under this condition, high pressure oil is injected into the tapered surface from the oil hole using a hydraulic pump or the like. Then, an oil film is formed on the tapered surface, and due to the high pressure, the diameter of the inner sleeve is slightly reduced and the diameter of the outer sleeve is expanded. When high-pressure oil is subsequently injected, it flows out from between the inner and outer sleeves at the small diameter end, enters the hydraulic chamber, and accumulates in the hydraulic chamber, where its pressure gradually increases. Therefore, the outer sleeve is in a state where it is easy to move due to the oil film, and moreover, it is pushed from the hydraulic chamber toward the large diameter end on the tapered surface.

Thereafter, when the outer sleeve is sufficiently pushed toward the large diameter end, the hydraulic pressure is released. Then, as the inner and outer sleeves try to return to their original diameters, the oil film disappears, and a high frictional force is generated between the two sleeves, so the outer sleeve no longer moves in the axial direction and maintains its position. .

Next, the piston body is pushed deep into the piston body using the pressing member, and the oil in the hydraulic chamber is expelled from the oil hole.

Finally, the above-mentioned pressing force on the inner sleeve is released, but at this time, the inner sleeve is tightened by the outer sleeve, so the set position is fixed as it is.

(Example) Hereinafter, an example device of the present invention will be described based on the accompanying drawings.

FIG. 1 is a longitudinal sectional view of the device of this embodiment in a state of use.

In the figure, a main shaft 1 of a machine tool is placed vertically on a base S, and a bearing B as an annular component is assembled together with a spacer B'.

An inner sleeve 3 is inserted into the main shaft 1 and inserted into an outer sleeve 2 having a tapered inner diameter surface.

The outer sleeve 2 is made thick so as to have sufficient rigidity, and its inner diameter surface is gently tapered. In the illustrated example, the inner diameter surface is made of a hard resin layer 21 formed by molding for manufacturing reasons such as easily matching the taper of the inner sleeve 3 with its counterpart, which will be described later, but this is not necessarily the case. Instead, it may be formed as a single thick-walled metal sleeve.

The large-diameter end of the inner diameter surface 22 of the sleeve 2 is located at the lower side, and an annular groove 25 for accommodating the O-ring 24 is formed therein. A portion 23 from the annular groove 25 to the large diameter end has a diameter larger than the diameter of the extended surface of the tapered inner diameter surface 22.

The small diameter end of the inner diameter surface 22 of the outer sleeve 2 is located at the upper part, and there is provided an annular step 26 that is larger than the diameter of the extended surface of the tapered inner diameter surface 22 and is open upward. There is. Further, the outer sleeve 2 is provided with oil holes 27 and 28 that reach the tapered inner diameter portion 22 and the bottom surface of the stepped portion, respectively.

On the other hand, the inner sleeve 3 is made thin and has a tapered outer diameter surface 32 that matches the inner diameter portion 22 of the outer sleeve. The inner sleeve 3 has a lower large-diameter end and an upper small-diameter end that protrude further than the outer sleeve 2 in the axial direction. The large-diameter end and the small-diameter end are made at right angles to the axis with extremely high precision during manufacture.

A threaded portion 33 is provided on the outer circumferential surface of the small diameter end of the inner sleeve 3, and a flange body 34 as a fixing member is attached to the flange body 34. 35 are arranged at multiple positions in the circumferential direction. An annular space is formed between the outer circumferential surface of the inner sleeve 3 and the inner circumferential surface of the stepped portion 26 of the outer sleeve 2 immediately below the flange body 34, and a piston body 4 as a sealing member is formed in the annular space.
are arranged. Annular grooves are formed on the outer and inner diameters of the piston body 4, into which O-rings 41 and 42 are fitted, respectively, to form a sealed hydraulic chamber 5.

Furthermore, a pressing means 6 used for operating the device of this embodiment is inserted above the inner sleeve 3. The pressing means 6 includes a spacer 61 whose end surfaces are manufactured with high precision in parallelism, and a hydraulic cylinder body 6.
The hydraulic pressure member 62 includes a piston body 62B housed in the piston body 2A, and a nut 63 screwed onto a threaded portion of the main shaft.

Next, a procedure for fixing a shaft component using the apparatus of this embodiment configured as described above will be explained.

First, shaft parts to be fixed to the main shaft 1 vertically mounted on the base S, such as the bearing B and the spacer in the illustrated case, are attached.
Insert B′.

Next, the inner sleeve 3 is loosely inserted into the outer sleeve 2, and the unit in which the piston body 4 and the flange body 34 are assembled is placed so that the outer diameter ends of the inner sleeve 3 and the outer sleeve 2 are located below. Then, insert it into the main shaft. At this time, the large-diameter end surface of the lower end of the inner sleeve 3 comes into contact with the end surface of the uppermost bearing B.

Next, the pressing means 6 is inserted into the spacer 61, the hydraulic pressing member 62, and the nut 63 in this order.

In this state, after lightly tightening the nut 63 of the pressing means 6, hydraulic pressure is applied as indicated by arrow P to press the piston body 62B downward. This pressing force presses the inner sleeve 3 in the axial direction through the spacer 61, and the inner sleeve 3, the bearing B, and the spacer B' are kept in a predetermined position. At this time,
The piston body 62B has a degree of freedom to incline by the clearance within the cylinder body 62A, and if the end face of the spacer 61 has a precisely perpendicular angle to the axis, the inner sleeve 3 can be moved in the circumferential direction. A uniform pressing force can be obtained.

Next, while maintaining the pressing force of the pressing means 6, the oil hole 28 communicating with the hydraulic chamber 5 of the outer sleeve 2 is sealed, and high pressure oil is injected into the oil hole 27 communicating with the tapered inner diameter surface 22. This high-pressure oil enters both ends of the sleeve while forming an oil film between it and the tapered outer diameter surface 32 of the inner sleeve 3. However, since an O-ring 24 is provided at the large inner diameter end of the outer sleeve 2 and is sealed from the inner sleeve 3, the oil film that grows downward stops here. On the other hand, the oil film that grows toward the small inner diameter end (upward) flows out from between the sleeves and accumulates in the hydraulic chamber 5. Then, the hydraulic pressure in the hydraulic chamber 5 gradually increases and reaches the supply pressure.

Due to the high-pressure oil film on the tapered surface, the inner sleeve 3 is reduced in diameter and the outer sleeve 2 is also slightly enlarged in diameter.
Moreover, since the outer sleeve 2 receives a downward pressing force from the hydraulic chamber 5, it moves so as to be pushed onto the tapered surface of the inner sleeve 3. This movement occurs because the outer sleeve 2 is pushed in by the pressing force from inside the hydraulic chamber 5 against the axial component force of the surface pressure due to the wedge action on the tapered surface, and the inner sleeve 2
When the pressure for tightening the shaft 1 reaches a predetermined value, the application of hydraulic pressure to the oil hole 27 is stopped. Then, the oil film on the tapered surface between the outer sleeve 2 and the inner sleeve 3 disappears, and as a result, both sleeves 2 and 3 try to return to their original diameters, and the two come into contact with extremely high surface pressure, resulting in a high frictional force. occurs. Therefore, the outer sleeve 2 can no longer be moved in the axial direction, and the inner sleeve 3 is also fixed in its axial position due to its strong tightening force.

In this state, the hydraulic pressure of the pressing means 6 is released, and the pressing means 6 is removed from the main shaft 1.

At the same time, if the oil hole 28 is opened and the piston body 4 is pressed by the push screw 35, the oil in the hydraulic chamber 5 is forced out through the oil hole 28 and into the hydraulic chamber by the movement of the piston body 4. will no longer remain. Therefore, even if the main shaft rotates at high speed during use, unbalance due to oil with bubbles remaining in the hydraulic chamber 5 will not occur. In this way, fixing of the shaft component is completed.

When removing the shaft component, if high-pressure oil is injected from the oil hole 27 without using the pressing means 6, the outer sleeve 2 will be pushed upward by the axial component of the pressure of the oil film on the tapered surface. (in the direction of the small inner diameter end) and the tightening force disappears. In this case, it is necessary to move the push screw 35 upward to a position where it does not interfere with the movement of the outer sleeve 2, so that the piston body 4 can freely retreat.

(Effects of the invention) Since the invention is as described above, it brings about the following effects.

Compared to conventional fixation of shaft parts using screws, the perpendicularity to the axis allows the shaft parts to be fixed with extremely high precision. Also, compared to stepped sleeves,
Work efficiency can be improved because the work can be completed in a short time and by one person.

Since the O-ring is arranged at the large inner diameter end of the outer sleeve, oil will not flow out from this part when an oil film is formed, and there is no risk of oil flowing into the bearings etc. located directly below.

An oil film is formed between the inner sleeve and the outer sleeve, and there is no oil between the inner sleeve and the shaft, so as in the case of a stepped sleeve,
There is no danger of the sleeve moving when the hydraulic pressure is released, and reliable positioning can be achieved.

Since the oil in the hydraulic chamber used when pushing the outer sleeve is discharged when the fixing work is completed, there is no element that causes unbalance when the main shaft is used, and its rotation accuracy is further improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view of an embodiment of the present invention during operation. 2... Outer sleeve, 3... Inner sleeve, 4...
Piston body, 5...Hydraulic chamber, 22...Tapered inner diameter surface, 26...Step part, 27...Oil hole, 28...Oil hole, 32...Tapered outer diameter surface, 34...Fixing member (flange body ), 35...Press member (push screw).

Claims (1)

[Claims for Utility Model Registration] A thick outer sleeve having a tapered inner diameter surface, and a thin inner sleeve having the same tapered outer diameter surface as the inner diameter surface of the outer sleeve and incorporated into the outer sleeve. , the outer sleeve has an annular stepped part on the inner diameter of the small inner diameter end, the diameter of which is larger than the diameter of the extended surface of the tapered surface, and which is open at the small inner diameter end;
An oil hole is provided to press oil in from the outside, and the annular space between the small outer diameter end of the inner sleeve and the inner diameter surface of the stepped part of the outer sleeve is sealed and hydraulic pressure is applied inward in the axial direction. A piston body forming a chamber is disposed, and the piston body is slid axially inwardly to open the hydraulic chamber by a pressing member attached to a fixed member fixed to the small diameter end of the inner sleeve. It is possible to reduce the volume, and when the inner sleeve is in its normal assembly position into the outer sleeve, the large outer diameter end is closer to the large inner diameter end of the outer sleeve, and the smaller outer diameter end is closer to the above fixed position. A fixing device for annular shaft parts, each of which protrudes axially beyond the members.