JPH09317778A - Main spindle bearing cooling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve initial rigidity of a bearing and the rigidity from the low and high speed by providing a cooling sleeve between a bearing inner race and a spindle, penetrating it into a cooling oil path from one end to the other end, and providing a feed path and a recovery path of the cooling oil to a bearing housing. SOLUTION: Cooling oil fed from a cooling oil entrance 9a of a housing 2 flows to a flow path entrance member 5 via a cooling oil feed path 9, a ring groove 21 of a feed path member 7, and a fine clearance. The cooling oil which passes through a flow path 14 of a cooling sleeve 4 is discharged from a cooling oil exit 10a via a flow outlet member 6, a recovery member 8, and a cooling oil recovery path 10. When the cooling oil flows through the sleeve 4, the inner race 3a of the bearing 3 is cooled. The temperature difference between the inner and outer races thus becomes smaller so that, when the initial pressurization is set not to become pressurization excess during high speed rotation, the initial pressurization is prevented from becoming too low and the initial rigidity of the bearing 3 can be set to high, so that the support rigidity of the spindle 1 can be secured from the low to high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle bearing cooling device applied to a spindle in a machine tool such as a grinding machine, a machining center or a lathe.

[0002]

2. Description of the Related Art The spindle speed of machine tool spindles has increased in recent years, and the dn value of the spindle bearing (d: bearing inner diameter dimension, n:
The number of rotations) has reached about 60 × 10 ^{4 to} 150 × 10 ⁴ . Such an increase in speed of the main spindle is accompanied by problems such as an increase in preload due to internal heat generation of the bearing and seizure.
In order to solve such problems, the following three measures are adopted. Reduce the initial rigidity of the main shaft bearing (lower the initial preload). Adopt jet lubrication. Cool the outer diameter surface of the spindle housing with cooling oil.

The above measures will be described with reference to a conventional example shown in FIG. 13. According to the above method, a thread groove-like groove portion 102 is formed on the outer diameter surface of a spindle housing 101, and a cooling jacket 103 is formed on the outside thereof. It is a method of flowing cooling oil. That is, the object is to cool the entire main spindle device and prevent the accuracy of the entire main spindle 100 from deteriorating due to heat generation. The above method is a method in which the bearing clearance is set to a large value in anticipation of heat generation at the maximum rotation speed for the main shaft bearing 104. The temperature distribution in the bearing 104 is (rolling element)>
Since the temperature is higher in the order of (inner ring)> (outer ring) and the temperature of the inner ring is higher than that of the outer ring, the internal clearance becomes smaller and the amount of preload increases with the operation. Therefore, it is necessary to reduce the initial preload.

[0004]

However, as described above, in the method of predicting the maximum number of rotations and setting the bearing gap to a large value, the heat generation is small when used at low speed rotation,
The bearing clearance does not become small, the amount of preload does not increase, and the supporting rigidity of the spindle 100 becomes insufficient. In particular, when the cooling jacket 103 is provided on the outer periphery of the housing 101 as in the cooling method, the outer ring side of the bearing 104 is cooled, so that the temperature difference between the inner and outer rings during high-speed operation becomes larger. At that time, it becomes necessary to reduce the initial preload in order to prevent an excessive preload, and the problem of insufficient rigidity during low-speed rotation increases. In many cases, it is necessary to use the machine tool at low speed from the viewpoint of the finish of machining, and it is difficult to improve the machining accuracy in this case. The jet lubrication mentioned above
It is a method of spraying lubricating oil from a nozzle etc. provided on the side surface of the bearing to both cool and lubricate the inside of the bearing, but it is not so adopted because of its complicated structure, and a large amount of lubricating oil is applied to the bearing. Since it is a method of spraying, there is a problem that resistance is generated in the rotation of the bearing and power loss of the main shaft occurs. As one type of jet lubrication, there is a method of discharging lubricating oil from a nozzle provided on the raceway surface of the inner ring (underrace lubrication), which also serves to cool the inner ring, but this also has a complicated structure and power Since there is a problem of loss and the nozzle is provided on the raceway surface of the inner ring, it is not preferable in terms of rolling life.

The present invention solves these problems. It is possible to improve the initial rigidity of the main shaft bearing, improve the rigidity from low speed to high speed, and have a simple structure and the problem of power loss. It is an object of the present invention to provide a spindle bearing cooling device that does not occur.

[0006]

In order to solve the above problems, the present invention provides a cooling sleeve between an inner ring of a main shaft bearing and a main shaft, and a cooling oil passage is provided from one end to the other of the cooling sleeve. It is provided by penetrating the end. The housing in which the main shaft bearing is installed is provided with a cooling oil supply passage for supplying cooling oil to the inlet of the passage of the cooling sleeve and a cooling oil recovery passage for collecting cooling oil from the outlet of the passage. According to this configuration, since the cooling sleeve for cooling the inner ring of the bearing is provided on the main shaft, the following actions can be obtained. In order to take heat from the inner ring, which has the highest temperature during driving,
The temperature difference between the inner and outer rings is reduced. Therefore, even if the initial preload is set so that the preload is not excessive at the time of high speed rotation, the initial preload does not become too low and the initial rigidity of the main shaft bearing can be made high. Therefore, the supporting rigidity of the spindle is ensured from low speed to high speed. Since only the cooling oil flows through the cooling sleeve, cooling can be performed without the resistance of rotation of the bearing such as jet lubrication. The bearing itself does not need to be processed with a nozzle for cooling oil, and the structure is simple. Since heat is taken from the inner ring, which has the highest temperature, deterioration of the lubricating oil due to heat can be prevented. Since heat is taken from the inner ring, which tends to become hot, deterioration of accuracy can be prevented. Since the main spindle is cooled, thermal expansion in the axial direction of the main spindle is suppressed, and the machining accuracy of the main spindle is improved.

The flow path of the cooling sleeve may be a through hole or a spiral groove formed on the inner diameter surface. When the spiral groove is used, the flow path can be formed long in the cooling sleeve, and the cooling can be efficiently performed with a small amount of cooling oil.

In the above construction, a flow passage inlet member having an introduction passage having one end communicating with the inlet of the cooling sleeve and the other end opening to the outer diameter surface is provided on the outer periphery of the main shaft. The housing may be provided with a supply passage member whose inner diameter surface is close to the outer diameter surface. The supply passage member is provided with an annular groove on the inner diameter surface facing the inlet portion of the introduction passage of the passage inlet member, and the cooling oil supply passage of the housing is opened at the bottom of the groove. As described above, by supplying the cooling oil through the flow path inlet member and the supply path member that are close to each other in the radial direction, the lubricating oil can be supplied from the housing to the cooling sleeve of the rotating main shaft with a simple configuration. . Further, since the oil is supplied through the annular groove, the cooling oil is smoothly and continuously supplied regardless of the rotation phase. Further, on the outer circumference of the main shaft, a flow path outlet member having a lead-out path having one end communicating with the outlet of the cooling sleeve and the other end opening to the outer diameter surface is provided, and the flow path outlet member has an outer diameter surface. A recovery passage member having inner diameter surfaces close to each other may be provided in the housing. The recovery passage member is provided with an annular groove on the inner diameter surface thereof, which faces the outlet of the outlet passage of the passage outlet member, and the cooling oil recovery passage of the housing is opened at the groove bottom. Thus, the cooling oil can be collected from the rotating cooling sleeve to the fixed housing with a simple structure.

Further, in the above structure, an annular projecting wall forming a labyrinth seal may be provided at an end portion of the inner diameter surface of the recovery passage member on the main shaft bearing side, in proximity to the side surface of the flow passage outlet member. The labyrinth seal also provides a sealing effect on the bearing, and the sealing property of the bearing is increased. In the above structure, the housing may be provided with a nozzle for ejecting lubricating oil to the main shaft bearing and a lubricating oil supply passage for supplying the lubricating oil to the nozzle.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. This example is applied to a spindle device in a machine tool such as a grinder, and the spindle 1
Are supported by the housing 2 via double-row main shaft bearings 3. This main shaft bearing cooling device is provided with double-row main shaft bearings 3,
3, the cooling sleeve 4 interposed between the inner ring 3a and the main shaft 1, the flow path inlet member 5 and the flow path outlet member 6 provided on both sides thereof, and the flow path inlet member 5 and the flow path outlet member. 6 is mainly composed of five parts including a supply path member 7 and a recovery path member 8 arranged on the inner diameter surface of the housing 1. A cooling oil supply passage 9 and a cooling oil recovery passage 10 are provided in the housing 2 so as to communicate with the supply passage member 7 and the collection passage member 8, respectively. An outer ring spacer 11 with a nozzle for air-oil lubrication is arranged between the main shaft bearings 3 and 3 in both rows. A lubricating oil supply passage 12 communicating with the outer ring spacer 11 with a nozzle and an oil recovery passage 13 for recovering lubricating oil or cooling oil from both sides of the main shaft bearings 3, 3 are formed in the housing 1. .

The cooling sleeve 4 is shown in FIGS. 5 (A) and 5 (B).
As shown in (1), the circular hole-shaped flow passages 14 penetrating linearly in the axial direction are provided at a plurality of positions in the circumferential direction. Circumferential grooves 15 and 16 are provided on both end surfaces of the cooling sleeve 4, and the channels 14 are opened in these circumferential grooves 15 and 16. Channel 14
May have a slope approaching the outer diameter side from the inlet 14a toward the outlet 14b as shown in FIG. 5 (C). This improves the oil flow due to the centrifugal force.
Further, the spiral groove such as the screw groove is provided on the inner diameter surface of the flow path 14 formed of the round hole, so that the surface area is increased and the heat dissipation efficiency is improved.

The flow path inlet member 5 in FIG. 1 has a plurality of L-shaped introduction paths 17 which are in communication with the entrance 14a of the flow path 14 of the cooling sleeve 4 at one end and open at the other end on the outer diameter surface in the circumferential direction. (Fig. 4). An annular positioning piece 5a fitted to the outer diameter surface of the cooling sleeve 4 and in contact with the width surface of the inner ring 3a of the main shaft bearing 3 is provided on the outer peripheral portion of the end of the flow path inlet member 5 on the side of the cooling sleeve. Inner diameter surface of the flow path inlet member 5,
And, an annular seal fitting groove is formed at the base end of the inner diameter surface of the annular positioning piece 5a, and a seal member such as an O-ring is provided inside to provide a space between the main shaft 1 and the outer diameter surface of the cooling sleeve 4. It is sealed. On the outer periphery of the annular positioning piece 5a, an annular protrusion 5b is formed near the side surface of the supply path member 7 to form a labyrinth seal.

The flow channel outlet member 6 has the same structure as the flow channel inlet member 5, and the outlet 14 of the flow channel 14 of the cooling sleeve 4 is provided.
L-shaped lead-out paths 18 having one end communicating with b and the other end opening to the outer diameter surface are provided at a plurality of circumferential positions (FIG. 6). An annular positioning piece 6a fitted to the outer diameter surface of the cooling sleeve 4 and in contact with the width surface of the inner ring 3a of the main shaft bearing 3 is provided on the outer peripheral portion of the end of the flow passage outlet member 6 on the side of the cooling sleeve. An annular seal fitting groove is formed at the base end of the inner diameter surface of the flow path outlet member 6 and the inner diameter surface of the annular positioning piece 6a, and a seal member such as an O ring is provided inside the main shaft 1 and the cooling sleeve. 4 and the outer diameter surface are sealed.

The flow path outlet member 6, the cooling sleeve 4, and the flow path inlet member 5 are externally fitted in this order to a portion of the main shaft 1 formed in a stepped shaft shape on the tip side of the step portion 1a, in this order. Together with the seal ring 19 for the labyrinth seal of
The nut member 20 screwed to the male screw portion of the above is fastened to the main shaft 1 by being tightened between the nut member 20 and the step portion 1a. The inner rings 3a, 3a of the main shaft bearings 3, 3 in both rows are sandwiched between the annular positioning pieces 5a, 6a of the flow path inlet member 5 and the flow path outlet member 6 together with the inner ring spacer 29 interposed therebetween. .

The supply passage member 7 has a minute gap (for example, about several tens to several hundreds of microns) on the outer diameter surface of the passage inlet member 5.
The inner diameter surface is close to the inner diameter surface, and an annular groove 21 is formed in the inner diameter surface as shown in FIG. Annular groove 21
Is formed so as to face the inlet portion of the introduction passage 17 of the passage inlet member 5, and a through hole 22 communicating with the cooling oil supply passage 9 of the housing 2 is opened at the groove bottom. An annular seal member such as an O-ring is provided around the opening of the outer diameter surface of the supply path member of the through hole 22, and an annular seal member such as an O-ring is provided to seal the inner diameter surface of the housing 2. The supply passage member 7 has a cross-sectional shape in which the outer diameter portion spreads to both sides in a brim shape, and notches 23 and 24 for oil discharge are formed at one or more circumferential positions of the brim portions on both sides thereof. ing.

The recovery path member 8 is similar to the supply path member 7 in that
The inner diameter surface is close to the outer diameter surface of the flow path outlet member 6 through a minute gap, and as shown in FIG. 7, an annular groove 25 is formed in the inner diameter surface. The annular groove 25 is formed so as to face the outlet portion of the outlet passage 18 of the passage outlet member 6, and a through hole 26 communicating with the cooling oil recovery passage 10 of the housing 2 is opened at the groove bottom. An annular seal member such as an O-ring is formed around the opening of the outer diameter surface of the recovery passage member of the through hole 26 to seal the inner diameter surface of the housing 1. The recovery passage member 8 has a cross-sectional shape in which the outer diameter portion spreads to both sides in a brim shape, and cutouts 27 and 28 for oil discharge are formed at one or more circumferential positions of the brim portions on both sides thereof. ing.

The supply passage member 7 and the recovery passage member 8 are arranged adjacent to the outside of the row of the outer rings 3b, 3b in the bearings 3, 3 in both rows, and the bearing outer rings 3b, 3b and the outer ring spacer with nozzle are arranged. 11, a step portion 2a on the inner diameter surface of the housing 1, and a housing lid 2A at the tip of the housing 2
It is installed in a tightened state between and. A seal ring 30 for a labyrinth seal is interposed between the supply passage member 7 and the housing lid 2A.

The main shaft bearings 3 in both rows are angular ball bearings, and are arranged so that the inclination angles of the contact angles face each other. The nozzle-equipped outer ring spacer 11 is provided with nozzles 11a for ejecting lubricating oil onto the raceways of the inner ring 3a of the main shaft bearings 3 on both sides at a plurality of circumferential positions on both sides.

The lubricating oil supply passage 12 provided in the housing 2 communicates with one end of the axial hole, and the lubricating oil inlet 12 is provided.
a is opened on the outer diameter surface of the housing and communicated from the other end of the axial hole into the outer ring spacer 11 with a nozzle through the radial hole. A lubricating oil supply device (not shown) for feeding the lubricating oil together with the carrier air is connected to the lubricating oil inlet 12a by a pipe. The oil recovery passage 13 in the housing 2 communicates with one end of the axial hole to open the oil recovery port 13a on the outer diameter surface of the housing, and the cutouts 23, 24, 27 of the supply passage member 7 and the recovery passage member 8 are formed. , 28 corresponding to each of the plurality of radial holes, which are opened on the inner diameter surface of the housing, are branched from the axial holes. Each of the cooling oil supply passage 9 and the cooling oil recovery passage 10 is composed of a radial hole provided in the housing 2, and has a cooling oil inlet 9a and a cooling oil outlet 10a on the outer diameter surface.
Are open. A threaded groove portion 2b is formed on the outer diameter surface of the housing 2, and a cooling jacket (not shown) is provided on the outer periphery thereof.

The operation of the above configuration will be described. Housing 2
The cooling oil supplied from the cooling oil inlet 9a of FIG.
As indicated by the arrow, the oil flows through the cooling oil supply passage 9 into the annular groove 21 of the supply passage member 7, and then flows into the opposing passage inlet member 5 through the minute gap. The inflowing cooling oil passes through the flow path 14 of the cooling sleeve 4, is recovered from the flow path outlet member 6 to the recovery path member 8, and is discharged from the cooling oil outlet 10a. During this time, the inner ring 3a of the main shaft bearing 3 is cooled when flowing through the cooling sleeve 4. The cooling oil that has deprived the inner ring 3a of heat is discharged from the cooling oil recovery port 10a of the housing 2 and cooled by an oil cooler (not shown).
It is supplied again from the cooling oil inlet 9a. When the cooling oil is supplied to the main shaft 1 that rotates at a high speed as described above, there is a slight gap between the supply passage member 7 and the passage inlet member 5 and between the passage outlet member 6 and the recovery passage member 8. But there is a gap, so
Cooling oil leaks from this gap. The leaked cooling oil is
As shown by the arrow in (B), it is collected outside the housing 2 through the cutouts 23, 24, 27, 28 provided in the supply passage member 7 and the collection passage member 8. The lubricating oil is supplied into the housing 2 from the lubricating oil inlet 12a together with the carrier air, and is jetted and supplied from the nozzle 11a of the outer ring spacer 11 with nozzle to the inner rings 3a of the main shaft bearings 3 on both sides. The lubricating oil supplied to the bearing 3 is collected together with the cooling oil from the cutouts 23 and 27 of the supply path member 7 and the recovery path member 8 on both sides of the bearing.

Since the inner ring 3a of the main shaft bearing 3 is cooled in this manner, the temperature difference between the inner and outer rings is reduced. For this reason,
Even if the initial preload is set so that the preload is not excessive at the time of high speed rotation, the initial preload does not become too low, and the initial rigidity of the spindle bearing 3 can be increased. Therefore, the supporting rigidity of the spindle 1 is ensured from low speed to high speed. The main shaft bearing 3 can be lubricated by either grease lubrication or oil lubrication, but considering the power loss of the main shaft 1, it is preferable to use air oil lubrication as in this example or oil mist lubrication. .

The flow passage 14 of the cooling sleeve 4 is a through hole in the axial direction in the above embodiment, but as shown in the examples shown in FIGS. 8 to 11, a spiral formed on the inner diameter surface of the cooling sleeve 4. It may be a groove. The cross section of the groove may be in the shape of a square groove as in the example of FIG. In this example, the flow path inlet member 5 and the flow path outlet member 6 are formed with a stepped inner diameter surface, and the large diameter portions 5c and 6c have spiral grooves formed in the flow path 1 respectively.
Both ends of 4 are opened. As described above, by forming the flow passage 14 as the spiral groove, the flow passage 14 can be formed long in the cooling sleeve 4, and the cooling can be efficiently performed with a small amount of cooling oil. Other configurations and effects in the example of FIG. 8 are the same as those of the example of FIG.

Further, as shown in FIG. 12, the recovery path member 8
At the end of the inner diameter surface of the main shaft bearing side, the flow path outlet member 6
An annular protruding wall 8b forming a labyrinth seal may be provided adjacent to the side surface of the. In this example, an annular recess 6b is formed on the side surface outer peripheral portion of the flow path outlet member 6, and the annular projection wall 8b is loosely fitted in the annular recess 6b. By configuring the labyrinth seal in this manner, the main shaft bearing cooling device also serves as a further seal for the main shaft bearing 3, and the hermeticity is increased. Other configurations and effects in this example are the same as those in the example of FIG.

[0024]

According to the spindle bearing cooling device of the present invention, since the cooling sleeve is provided between the inner ring of the spindle bearing and the spindle, and the cooling oil passage is provided in the cooling sleeve, the initial rigidity of the spindle bearing is improved. The advantages are that the rigidity can be improved from low speed to high speed, the structure is simple, and the problem of power loss does not occur. When the flow path of the cooling sleeve is formed in a thread groove, the flow path can be lengthened to effectively cool with a small amount of cooling oil. When a flow path inlet member and a supply path member and a flow path outlet member and a recovery path member that are radially close to each other are provided between the main shaft and the housing, a cooling that rotates with a fixed housing with a simple configuration Cooling oil can be supplied to and collected from the sleeve. When the annular projecting wall forming the labyrinth seal is provided between the flow path outlet member and the recovery path member, the cooled cooling oil is prevented from flowing to the bearing, and the sealing effect on the bearing is also improved. . Further, when the main shaft bearing cooling device is used in combination with the structure in which the main shaft bearing is jetted from the lubricating oil jet nozzle, effective cooling and lubrication are performed.

[Brief description of drawings]

FIG. 1 is a sectional view of a spindle bearing cooling device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the oil flow path.

3A and 3B are a sectional view and a front view of a supply passage member of the same spindle bearing cooling device, respectively.

4A and 4B are a sectional view and a front view of a flow path inlet member, respectively.

5A to 5C are respectively a front view and a sectional view of a cooling sleeve, and a partial cross section of a modified example of the cooling sleeve.

6A and 6B are a front view and a cross-sectional view of a flow path outlet member, respectively.

7 (A) and 7 (B) are a cross-sectional view and a front view of the recovery path member, respectively.

FIG. 8 is a sectional view of a spindle bearing cooling device according to another embodiment of the present invention.

FIG. 9 is a front view and a sectional view of the cooling sleeve.

FIG. 10 is a front view and a cross-sectional view of the flow path inlet member.

FIG. 11 is a front view and a cross-sectional view of the flow path outlet member.

FIG. 12 is a sectional view of a spindle bearing cooling device according to still another embodiment of the present invention.

FIG. 13 is a sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Main shaft 2 ... Housing 3 ... Main shaft bearing 3a ... Inner ring 4 ... Cooling sleeve 5 ... Flow path inlet member 6 ... Flow path outlet member 7 ... Supply path member 8 ... Recovery path member 9 ... Cooling oil supply path 10 ... Cooling oil Recovery path 11a ... Nozzle 12 ... Lubricating oil supply path 14 ... Flow path

Claims (6)

[Claims] 1. A cooling sleeve is provided between an inner ring of a main shaft bearing and a main shaft, and a cooling oil passage is provided through the cooling sleeve from one end to the other end, and a housing in which the main shaft bearing is installed is provided. A spindle bearing cooling device provided with a cooling oil supply passage for supplying cooling oil to the inlet of the passage of the cooling sleeve and a cooling oil recovery passage for collecting the cooling oil from the outlet of the passage. 2. The spindle bearing cooling device according to claim 1, wherein the flow path of the cooling sleeve is a spiral groove formed on an inner diameter surface. 3. A flow passage inlet member having an introduction passage, one end of which communicates with an inlet of the cooling sleeve and the other end of which is opened to an outer diameter surface, is provided on an outer periphery of the main shaft, and the outside of the flow passage inlet member is provided. A supply passage member whose inner diameter surface is close to the radial surface is provided in the housing, and an annular groove facing the inlet portion of the introduction passage of the flow passage inlet member is provided on the inner diameter surface of the supply passage member, and the groove bottom of the annular groove is provided. The cooling oil supply passage of the housing is opened in the housing.
Alternatively, the spindle bearing cooling device according to claim 2. 4. A flow path outlet member is provided on the outer periphery of the main shaft, the flow path outlet member having a lead-out path having one end communicating with the exit of the cooling sleeve and the other end opening to the outer diameter surface. A recovery passage member whose inner diameter surface is close to the radial surface is provided in the housing, and an annular groove facing the outlet portion of the outlet passage of the flow passage outlet member is provided on the inner diameter surface of the recovery passage member. The cooling oil recovery passage of the housing is opened in the housing.
Alternatively, the spindle bearing cooling device according to claim 2 or claim 3. 5. An annular projecting wall forming a labyrinth seal in the vicinity of the side surface of the flow path outlet member is provided at an end portion of the inner diameter surface of the recovery passage member on the spindle bearing side.
Spindle bearing cooling device described. 6. The main shaft according to claim 1, wherein the housing is provided with a nozzle for ejecting lubricating oil to the main shaft bearing, and a lubricating oil supply passage for supplying the lubricating oil to the nozzle. Bearing cooling device.