JPH05164127A - Prepressurizing device for bearing - Google Patents

Abstract

PURPOSE:To support a rotation axis without deteriorating a rigidity in a wide rotation area from a low speed rotation to a high speed rotation. CONSTITUTION:The pressure of a pressure oil supplied to holes 18 from a hydraulic pressure supply device 21 is set in accordance with the rotating speed of a rotation axis 1. Pistons 19 are moved by this pressure and the outer rings of rolling bearings 3 are supported by the pistons 19, so that the deterioration of rigidity of the rotation axis 1 is prevented and the damage of the rolling bearings 3 are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing preloading device, and more particularly to a bearing preloading device capable of switching between constant pressure preloading and constant position preloading.

[0002]

2. Description of the Related Art With the increase of aluminum products and the improvement of productivity, the spindles of machine tools such as machining centers are
Rotation in a range from low-speed rotation for heavy cutting to high-speed rotation for light cutting is being studied.

Generally, the rotation speed of the rotating shaft is 1000 rpm.
For the preload of the bearing in the high-speed rotation region as described above, the clearance between the bearing and the spacer, the amount of preload, and the preload method are set in consideration of the expansion of the bearing due to frictional heat and centrifugal force. This preload method includes constant pressure preload and constant position preload. However, if the preload of the bearing is set to be suitable for high speed rotation, the rigidity of the rotating shaft at low speed rotation will be reduced, and if it is set to be suitable for low speed rotation, seizure or the like will occur at high speed rotation.

As a constant pressure preloading technique for such low speed rotation to high speed rotation, for example, the actual open shovel 62-12.
There is a bearing preload adjusting device disclosed in Japanese Patent No. 6616.
This device uses a hydraulic pressure to set a high preload on the bearing during low speed rotation and reduce the preload on the bearing during high speed rotation.

[0005]

Since the constant pressure preload can freely set the preload of the bearing, it can be applied to a wide range of rotation of the rotary shaft from low speed rotation to high speed rotation. However, in the high-speed rotation region of the rotary shaft where the preload must be set low, the rigidity of the rotary shaft is extremely reduced.

In view of the above circumstances, an object of the present invention is to provide a bearing preloading device capable of coping with a wide rotation range from low speed rotation to high speed rotation without lowering the rigidity of the rotating shaft. To do.

[0007]

In order to achieve the above object, according to the present invention, a housing supporting a rotating shaft via a rolling bearing has a plurality of holes radially facing the outer ring of the rolling bearing. And a piston that slidably fits into each hole is provided, an oil whose pressure is adjusted is supplied to the hole, and the piston is brought into contact with the outer ring of the rolling bearing at a predetermined pressure. It was

Further, an annular cylinder slidably fitted in a housing supporting the rotary shaft and having an annular groove formed between the housing and the inner peripheral surface thereof, and a groove formed by the housing and the cylinder. An outer ring spacer of the rolling bearing is configured by an annular slider that is movably fitted and that forms an annular oil groove between the inner peripheral surface of the housing and the end surface of the cylinder. A plurality of holes are formed in the radial direction so as to face the slider, a plurality of pistons that slidably fit in the holes are provided, and an oil supply device that supplies pressure oil for constant pressure preload is connected to the oil groove. Then, the piston was moved into the hole of the housing, and a hydraulic device for supplying pressure oil for fixing the cylinder and the slider forming the outer ring spacer was connected.

[0009]

[Operation] By supporting the outer ring of the rolling bearing at a pressure that corresponds to the rotational speed of the rotating shaft, the expansion of the rolling bearing is absorbed, and it is possible to prevent excessive pressure from being applied to the rolling bearing and to increase the rigidity of the rotating shaft. It can be dealt with without lowering.

Then, by supplying oil having a pressure corresponding to a predetermined preload to the oil groove, the cylinder and the slider are moved to apply a preload of a predetermined pressure to the rolling bearing. In this state, pressure oil is supplied to the hole of the housing to fix the cylinder and slider with the piston. In other words, the bearing preload is set at a constant pressure suitable for the rotation speed of the rotating shaft, and by maintaining the set state as a fixed position preload, the rigidity of the rotating shaft can be set in a wide rotation range from low speed rotation to high speed rotation. It can be dealt with without lowering.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show a first embodiment of the present invention, in which a rotary shaft 1 having a pulley 25 for power transmission is rotatably supported by a housing 2 via a rolling bearing 3. Has been done. The inner ring spacers 4 and 5 are mounted on the rotary shaft 1 so as to be located between the rolling bearings 3. The sleeve 6 is attached to one end of the rotary shaft 1 and is pressed against the inner ring of the rolling bearing 3 by a nut 8 via a washer 7.

The outer ring spacer 9 and the outer ring spacer 19a are movably inserted in the housing 2 so as to be located between the rolling bearings 3. The flange 13 is fixed to one end of the housing 2 and is in contact with the outer ring of the rolling bearing 3.

The holes 18 are formed radially in the housing 2 so as to face the outer ring of the rolling bearing 3, respectively. The piston 19 is slidably inserted in the hole 18. The O-ring 20 is attached to the piston 19.
The hydraulic pressure supply device 21 is connected to the hole 18.

With such a configuration, by supplying the pressure oil set from the hydraulic pressure supply device 21 to the hole 18 in accordance with the rotational speed of the rotary shaft 1, the piston 19 is rolled.
The outer ring of the rolling bearing 3 is supported by the piston 19. By rotating the rotary shaft 1, the rigidity of the rotary shaft 1 can be maintained regardless of the rotation speed.

The pressure of the pressure oil supplied to the hole 18 is set high when the rotary shaft 1 is rotated at a low speed, and is set low when the rotary shaft 1 is rotated at a high speed. That is, the rotating shaft 1
During low-speed rotation in which the expansion of the rotary shaft 1 and the rolling bearing 3 due to the centrifugal force and heat generated by the rotation of the rotary shaft 1 is small, the pressure of the pressure oil is set high to prevent the rigidity of the rotary shaft 1 from decreasing. Further, at the time of high-speed rotation in which the expansion becomes large, the pressure of the pressure oil is set to be low to allow the outer ring of the rolling bearing 3 to expand, thereby alleviating the increase in the pressure applied to the rolling bearing 3 and rolling the bearing 3. It prevents seizure and abrasion of the rotating shaft 1 and prevents the rigidity of the rotating shaft 1 from decreasing.

In this way, the rotating shaft 1 can be rotated in a wide rotation range from low speed rotation to high speed rotation without lowering the rigidity. FIGS. 3 to 5 show a second embodiment of the present invention. As shown in the figure, the rotary shaft 1 is rotatably supported by the housing 2 via a rolling bearing 3. Inner ring spacers 4 and 5 are rolling bearings 3
It is mounted on the rotary shaft 1 so as to be located between the two. The sleeve 6 is attached to one end of the rotary shaft 1 and is pressed against the inner ring of the rolling bearing 3 by a nut 8 via a washer 7.

The outer ring spacer 9 is movably inserted in the housing 2 so as to be located between the rolling bearings 3.
The cylinder 10 is located between the rolling bearings 3,
It is movably inserted in the housing 2. Slider 1
1 is slidably mounted in a groove formed between the housing 2 and the cylinder 10 so as to be located between the rolling bearings 3. An oil groove 12 is formed between the housing 2, the cylinder 10 and the slider 11. The flange 13 is fixed to one end of the housing 2 and faces the outer ring of the rolling bearing 3. The O-ring 14 is provided between the housing 2 and the cylinder 10, and between the housing 2 and the slider 1.
1 and between the cylinder 10 and the slider 11. The oil supply hole 15 is formed in the housing 2 so as to communicate with the oil groove 12. The hydraulic pressure supply device 16 for constant pressure is connected to the oil supply hole 15 via a pressure gauge 17 for confirmation.

The holes 18 are radially formed in the housing 2 so as to face the cylinder 10 and the slider 11, respectively. The piston 19 is slidably inserted in the hole 18. The O-ring 20 is attached to the piston 19. The home position hydraulic pressure supply device 21 is connected to the hole 18.

In the above structure, the pressure in the hole 18 is released via the hydraulic pressure supply device 21. Then, piston 1
9, the pressing force of the cylinder 10 and the slider 11 is released, and the cylinder 10 and the slider 11 are moved to the rotary shaft 1
It becomes possible to move in the axial direction of. At the same time, the hydraulic pressure supply device 16
When the pressure of the oil in the oil groove 12 is released through the outer groove of the rolling bearing 3, the outer ring of the rolling bearing 3 moves in a direction of releasing the preload added by the elasticity, and the preload of the rolling bearing 3 is released.

In this state, the supply pressure of the hydraulic pressure supply device 16 is set to a value suitable for the rotation speed of the rotary shaft 1, and the oil supply hole 1
Pressure oil is supplied to the oil groove 12 via 5. Then, the cylinder 10 and the slider 11 move in a direction to widen the oil groove 12, push the outer ring of the rolling bearing 3, and apply a preload to the rolling bearing 3. At this time, the preload of the rolling bearing 3 is proportional to the pressure of the oil supplied to the oil groove 12.

In this way, the hydraulic pressure supply device 21 is actuated to supply the pressure oil to the hole 18 while the rolling bearing 3 is preloaded. Then, the pressure of the oil supplied to the hole 18 causes the piston 19 to move in the direction of the axis of the rotating shaft, pressing the cylinder 10 and the slider 11 and restraining the movement in the axial direction. Therefore, the rolling bearing 3 is in a state where the fixed position preload is applied.

In this state, the rotating shaft 1 can be rotated without lowering the rigidity even during high-speed rotation with a small preload.

In the above embodiment, when the preload of the rolling bearing 3 is lowered, the rotary shaft 1 is rotated at a low speed when the pressure in the oil groove 12 is released or after the pressure oil is supplied to the oil groove 12. Alternatively, the preload of the rolling bearing 3 may be positively released or switched.

6 and 7 show another embodiment of the present invention, in which the same parts as those in FIGS. 3 to 5 are designated by the same reference numerals. The piston 19 has wings 19
a is formed and is urged in the outer peripheral direction of the housing 2 by the spring 22 hung on the blade 19a.

With such a structure, the piston 19 is moved by the spring 22 when the preload is switched.
Further, it can be forcibly separated from the slider 11, and the cylinder 10 and the slider 11 can be moved without contacting the piston 19.

[0026]

As described above, according to the present invention, a plurality of holes are formed in a radial direction in a housing that supports a rotating shaft through a rolling bearing so as to face the outer ring of the rolling bearing, and A piston that slidably fits into the hole is provided, and a hydraulic pressure supply device that supplies pressure-adjusted oil to the hole and causes the piston to abut the outer ring of the rolling bearing at a predetermined pressure, or a rolling bearing It is slidably fitted to the housing that supports the rotating shaft through the ring, and it is slidable in the annular cylinder that forms an annular groove between it and the inner peripheral surface, and in the groove formed by the housing and the cylinder. And an annular slider that forms an annular oil groove between the inner peripheral surface of the housing and the end surface of the cylinder, and forms an outer ring spacer of the rolling bearing, and the housing includes the cylinder and the slider. versus To form a plurality of holes in the radial direction, to provide a plurality of pistons slidably fitted in each hole, to connect a hydraulic pressure supply device for supplying pressure oil for constant pressure preload to the oil groove, Since the piston is moved into the hole of the housing and the hydraulic pressure supply device that supplies the pressure oil that fixes the cylinder and the slider that form the outer ring spacer is connected, it is possible to reduce the rigidity from low speed to high speed rotation. The rotating shaft can be rotated in a wide rotating area.

[Brief description of drawings]

FIG. 1 is a side sectional view of a bearing preload device showing a first embodiment of the present invention.

FIG. 2 is a front sectional view of FIG.

FIG. 3 is a side sectional view of a bearing preloading device showing a second embodiment of the present invention.

FIG. 4 is a front sectional view of FIG.

FIG. 5 is an enlarged view of a piston in each of the embodiments.

FIG. 6 is a front sectional view of a bearing preloading device showing a third embodiment of the present invention.

FIG. 7 is an enlarged view of the piston in FIG.

[Explanation of symbols]

1 rotary shaft, 2 housing, 3 rolling bearing, 10 cylinder, 11 slider, 18 holes,
19 pistons, 16 and 21 hydraulic pressure supply device,

Claims (2)

[Claims] 1. A rolling bearing preloading device for supporting a rotating shaft, wherein a plurality of holes are formed in a radial direction in a housing supporting the rotating shaft via a rolling bearing so as to face an outer ring of the rolling bearing, respectively. Is provided with a piston slidably fitted in the hole, and a hydraulic pressure supply device is provided for supplying the pressure-adjusted oil to the hole and for bringing the piston into contact with the outer ring of the rolling bearing at a predetermined pressure. And bearing preload device. 2. A rolling bearing preloading device for supporting a rotating shaft, which is slidably fitted to a housing supporting the rotating shaft via a rolling bearing and has an annular groove between the housing and the inner peripheral surface thereof. By the annular cylinder to be formed and the annular slider which slidably fits in the groove formed by the housing and the cylinder and which forms an annular oil groove between the inner peripheral surface of the housing and the end surface of the cylinder. An outer ring spacer of a rolling bearing is configured, a plurality of holes are formed in the housing in the radial direction so as to face the cylinder and the slider, and a plurality of pistons slidably fitted in the respective holes are provided. A hydraulic pressure supply device for supplying a constant pressure preload pressure oil to the oil groove is connected, the piston is moved into a hole of the housing, and a pressure oil for supplying a pressure oil for fixing the cylinder and the slider forming the outer ring spacer is supplied. Pressure unit of the bearing, characterized in that the connecting device.