JPH04141346A - Cooling mechanism for spindle of machine tool - Google Patents

Abstract

PURPOSE:To reduce the thermal displacement of a spindle and the useless load of a spindle driving motor, by performing the indirect cooling of the spindle bearing outer periphery with a lubrication oil being circulated in a jacket provided on a spindle housing, also performing a direct cooling with this lubrication oil being injected to the spindle bearing. CONSTITUTION:The cooling and feeding/delivery device 17 of a cooling(lubrication) liquid, a jacket 15 and 16 are connected by a coolant feeding pipe 18. The space between the jackets 15, 16 and lubrication oil feeding nozzles 19 - 22 installed in each spacer space in opposition to the spindle bearing is connected by an oil feeding pipe, and the lubrication oil is recovered from each both sides of bearings 5 - 8 by the discharging holes 23 - 27 open for each spacer space. Thus, the bearing part is cooled/lubricated effectively and yet in with range only by circulating one kind of cooling/lubricating oil, especially, the feed/discharge of the cooling/lubrication oil can be adjusted finely according to the difference in the heating or cooling quantity caused for the bearing structure and the arrangement thereof, etc., being different.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling mechanism for a main shaft of a machine tool.

[Conventional technology]

The main spindle bearing device of a machine tool generates heat due to load drive during operation, and as a result of heat expansion of the main spindle due to heat conduction, for example, the main spindle extends relative to the housing, and during operation, the tool position relative to the workpiece changes, and heat generation occurs. - There are inconveniences such as deformation of the spindle's posture due to uneven heat radiation.

As a countermeasure, conventionally, a coolant is passed through the jacket around the housing of the main shaft bearing to absorb the thermal energy generated from the main shaft bearing.

Alternatively, a cooling air-oil mixed mist is directly blown onto the main shaft bearing to absorb the generated heat.

In addition, it supplies lubricating and cooling oil directly to the main shaft bearing itself.
Circulate to cool heat generating parts.

One or more of the following treatments were provided.

[Problem to be solved by the invention]

However, the indirect method in which only the outer periphery of the housing of the main shaft bearing is cooled has the disadvantage that the bearing device is not sufficiently cooled, and therefore the thermal displacement of the main shaft cannot be reduced.

With the method of directly cooling the main shaft bearing with coolant or gas, the cooling effect cannot be said to be excellent above a certain rotation speed of the main shaft, and the housing, bearing mounting mechanism, etc. Temperature gradients are likely to occur, which may cause posture deformation in the main shaft.

In addition, due to the structure, some bearings can easily collect coolant or mist, while others cannot. occurs, generating heat and causing thermal displacement of the spindle.

Moreover, the load on the main shaft drive motor also increases accordingly, which is undesirable.

A technology has been developed that can reduce thermal displacement of the main shaft by using both a jacket cooling method for the bearing housing and a method for directly cooling the main shaft bearing. lubrication) and separate equipment [Jacket cooling may be liquid cooling, and bearing equipment cooling generally uses a gas/liquid mixed fluid or lubricating oil, but the cooling (lubrication) equipment for both is separate. [High possibility] would complicate the structure of the spindle cooling system,
This not only increases the number of causes of troubles, but also increases costs.

Therefore, the present invention solves the above-mentioned various problems inherent in conventional devices, and in short, the present invention aims to reduce the thermal displacement of the spindle in a machine tool and reduce the unnecessary load on the spindle drive motor. The purpose is to provide a cooling mechanism for the main shaft of a machine.

[Means to solve the problem]

In order to achieve the above-mentioned object, the present invention includes each of the constituent elements as described below.

(1) Indirect cooling of the outer periphery of the main shaft bearing is performed by circulating lubricating oil in a jacket provided in the main shaft housing, and direct cooling is performed by jetting the lubricating oil onto the main shaft bearing. Main spindle cooling mechanism for machine tools.

(2) An oil recovery port is formed in the gap on both the supply side of the lubricating oil spouted to the main shaft bearing and the side where the lubricating oil passes through the bearing, and a suction pump is specially connected to the The above (1) consists of collecting lubricating oil.
Main spindle cooling mechanism of machine tool described in section.

[For production]

Cooled lubricating oil is passed through the jacket of the bearing housing to uniformly and indirectly cool the outer peripheral portion of the housing over a wide range, and the jacket is communicated with nozzles disposed opposite to each of the main shaft bearings.

The cooling (lubricating) liquid ejected from the nozzle is supplied to the main shaft bearing, lubricates the bearing, and directly cools the bearing. The cooling (lubricating) fluid that cools and lubricates each main shaft bearing remains in the respective bearing mounting spaces, and is connected to the cooling fluid recovery holes that open in the respective spaces corresponding to each bearing. Separate suction pumps are connected to each recovery line to independently follow the cooling characteristics of each bearing and to effectively recover the cooling fluid.As a result, the characteristics of each bearing can be adjusted independently. Set the cooling and lubrication amounts accordingly.

In short, it realizes individual systemization of cooling (lubricating) liquid recovery.

In this way, the amount of heat generated by the main shaft bearing and the drive torque of the main shaft that is lost due to effects such as entrainment and stirring caused by the accumulation of used lubricant can be minimized, and thermal displacement of the main shaft can also be reduced. can.

The cooling and lubricating fluid recovered from the main shaft bearing passes through the suction pump and is sent to the lubricating oil tank/cooling device, and from the tank it is again supplied to the jacket of the bearing housing, thereby performing an overall circulation action.

Furthermore, by suctioning used lubricating oil from both the side where the lubricating oil was injected into the bearing and the side through which it has penetrated, the lubricating oil is ensured to circulate around the bearing, and any excess lubricating oil is removed. , is collected without being retained in the bearing device.

〔Example〕

An embodiment of the device of the present invention will be described below with reference to the drawings, but the structure of each member constituting the embodiment may be subject to appropriate design changes within the technical level of the industry at the time of filing of the present invention. Since it is possible, the constituent elements of the present invention should not be interpreted as being limited based only on the structure of the embodiments described below, unless a special reason is given.

FIG. 1 shows a side cross section and a cooling system diagram of an embodiment of a spindle device for a machine tool according to the present invention.

In the figure, ] is the main shaft, one end of which extends outside the housing of the machine tool, has a tapered hole 2 on the end face into which the shank of the tool is fitted, and the other end is the motor 3 mounted on the machine.
It is directly connected to the output shaft 4 of.

The main shaft 1 is supported by a housing 12, which will be described later, by a plurality of bearings 5 to 8 arranged discontinuously along its longitudinal axis, and in this embodiment, the roller bearings are 5. A ball bearing 6 is placed with a spacer 9 in between, a ball bearing 7 is placed with a spacer 10 in between, and a spacer 11 is placed next to the roller bearing 8 at a slight distance from the motor 3.

Each of the above-mentioned bearings and spacers are housed in the housing 12 of the machine tool, and are attached to each other so that they cannot move or rotate.

Therefore, the space between the bearings formed by the spacers is divided between the circumferential surface of the main shaft 1 and the housing 12, respectively.
It can be understood that the bearings are substantially independent, surrounded by the inner wall of the bearing, and separated from each other by the bearings.

However, although no spacer is provided between the bearings 7 and 8 in the longitudinal axis direction of the main shaft 1, it is possible to tighten the main shaft 1 by providing a step or by fixing a ring to the shaft. A configuration equivalent to that provided by adding a spacer to this part is achieved.

Note that the electric motor 3 is attached to a housing 12 of a machine tool.

13 and 14 are coolant circulation jackets 15. lf
The outer cover of the housing is provided with no gaps on the outer periphery corresponding to the mounting positions of the bearing rows 5 to 7 and the bearing 8 through the housing 12. (with one intervening).

Note that 34 is a presser plate for the main shaft bearing 5 that is loosely fitted into the outer extension of the main shaft 1 and fixed to the housing 12.

” 17 separately provided for the main shaft bearing device of double structure.
18 is a cooling/supply/delivery device for cooling (lubricating) liquid;
A coolant supply pipe that branches and supplies downstream to the jackets 15 and 16 connects the supply/delivery device 17 and each jacket 15, 16 of the housing.

Reference numerals 19 to 22 denote lubricating oil supply nozzles that face the main shaft bearing and are installed in each spacer space, and oil supply pipes are provided to connect each nozzle 19 to 22 and the jackets 15 and 16, respectively. .

Reference numerals 23 to 27 are discharge holes for lubricating oil, etc., which open into the spacer spaces, respectively, so that lubricating oil can be recovered from both sides of the bearings 5 to 8.

That is, the lubricating oil supplied from the nozzle ]9 is discharged from the discharge hole 2.
3 and 24, the lubricating oil supplied from the nozzle 20 is supplied from the discharge holes 24 and 25, and the lubricating oil supplied from the nozzle 21 is supplied from the discharge holes 25 and 26 to the nozzle 22.
The lubricating oil supplied from the exhaust holes 26 and 27 is sucked from the exhaust holes 26 and 27, respectively.

Suction pumps 28 to 32 with inverter motors are each independently connected to the downstream side of each oil discharge pipe connected to the discharge holes 23 to 27.

The output of the inverter motor is controlled based on the signal from the oil temperature sensor of the used lubricating oil collected from each spacer space, and when the collected oil temperature is higher than a predetermined value, the function of the suction pump is increased and the result is , the supply amount of cooling lubricant is adjusted to be increased, and if the amount is relatively low, the suction pump is operated normally.

Therefore, the used lubricating oil collected from each spacer space is Even if there is a difference in oil temperature, by individually controlling the ability of each action pump to discharge used lubricating oil from the spacer space, the indirect cooling effect of the jacket on the outer circumference of the bearing can be improved. Together, during operation, the main shaft and each bearing part can be cooled and lubricated so that they all stay within a temperature range close to the design value.

However, in the case of the bearing structure of standard models, based on experience,
Since the amount of heat generated by each bearing part can be predicted or measured in advance, by adjusting the capacity of the cooling lubricant supply nozzle or the corresponding suction pump according to the amount of heat generated, it is possible to use the inverter. There is no need to install a motor or the like.

In this way, it is possible not only to adjust the temperature of each bearing of the main shaft to within a predetermined range, but also to keep the used lubricating oil in the required amount in each spacer space and to rotate and agitate it as the main shaft bearing is driven. It is possible to prevent inconveniences such as generation of heat due to such causes or unnecessary consumption of torque per rotation of the spindle.

That is, it is possible to minimize the thermal deformation of the main shaft during operation within a predetermined range, and it is also possible to minimize loss torque due to agitation of the lubricating oil.

The lubricating oil discharged from the suction pumps 28 to 32 is
All the lubricating oil is discharged into the lubricating oil tank 33 and the lubricating oil remains in the tank 33.

The lubricating oil retained in the tank 33 is transferred to the lubricating oil cooling/supplying device 17, and again transferred to the jackets 5 and 16 through the cooling (lubricating) liquid supply pipe 18, and thus the cooling/lubricating oil is attached to the spindle device. It circulates through the cooling mechanism.

In addition, cooling (lubrication) supplied to jackets 15 and 16
If necessary, it is not necessary to use all of the liquid for cooling and lubricating the main shaft bearing.For example, a bypass flow path is provided for the bearing cooling mechanism, and the excess cooling liquid is used for cooling and lubricating the main shaft bearing. It is also possible to return the lubricating oil directly to the lubricating oil cooling/supplying device 17 from there.

As mentioned above, the main shaft cooling mechanism of this embodiment effectively cools and lubricates the bearing portion over a wide range by simply circulating one type of cooling/lubricating oil, and in particular, the bearing structure, its arrangement, etc. Cooling and lubricating oil supply and discharge can be finely adjusted in response to differences in heat generation or cooling amount at the relevant location due to differences in the temperature.Also, since the adjustment of the cooling action quickly corresponds to the bearing temperature, thermal deformation of the main shaft can be prevented. within the specified range, and
The loss of the spindle due to agitation of used lubricating oil is reduced by 1 - 1 lux.
] was able to be reduced.

〔Effect of the invention〕

Since the following is as follows, according to the device of the present invention, (1
) Indirect cooling that cools the main shaft bearing (heat source) from the outer periphery;
Since direct cooling by the nozzle is also used, the cooling effect is good and the response speed to temperature fluctuations of the bearing device is fast.

(2) Direct cooling of the main shaft bearing tends to cause temperature gradients near the entrance and exit of the cooling (lubrication) fluid, but by using indirect cooling with a jacket, the equipment can be cooled almost evenly. This made it possible to reduce thermal deformation of the spindle.

(3) Since the suction mechanisms are independently connected to the required locations (each spacer space), the amount of cooling and lubricating oil supplied (cooling capacity) can be set and adjusted according to the conditions of each spindle bearing. As a result, it is possible to reduce heat generation caused by agitation of used lubricating oil and reduce the load on the main shaft motor.

(4) By suctioning used lubricating oil from both the side where lubricating oil is injected into the bearing and the side through which lubricating oil has penetrated, lubricating oil is reliably circulated around the bearing and an excess amount is supplied. The lubricating oil does not remain in the equipment and is effectively recovered.

(5) For indirect cooling of the spindle outer periphery and direct cooling of the spindle bearing, only one type of lubricating oil is used and circulated within the device, so only one lubricating oil cooling device is required, which is economical.

These and other special functions and effects cannot be expected from conventional spindle cooling mechanisms for machine tools.

[Brief explanation of drawings]

FIG. 1 shows a side cross section of the main shaft cooling mechanism and a cooling fluid circulation system diagram according to the present invention. 1. Main shaft, 3. Electric motor, 5-8 Main shaft bearing, 12. Housing, 15.16. Jacket, 17. Lubricating oil cooling/supply device, 18. Cooling (lubricating) liquid supply pipe, 19-22.・・Cooling liquid supply nozzle, 23-27・Lubricating oil discharge pipe, 28-32・・Choice 33 for attaching inverter motor・・
Lubricating oil tank, 34...pressing plate. 2...Taber hole, 4 Output shaft, 9~1 spacer, 1.3.14...Outer cover, Bump,

Claims (2)

[Claims] (1) Indirect cooling of the outer periphery of the main shaft bearing is performed by circulating lubricating oil in a jacket provided in the main shaft housing, and direct cooling is performed by jetting the lubricating oil onto the main shaft bearing. Main spindle cooling mechanism for machine tools. (2) An oil recovery port is formed in the gap on both the supply side of the lubricating oil spouted to the main shaft bearing and the side where the lubricating oil passes through the bearing, and a suction pump is specially connected to the Claim (1) consisting of collecting lubricating oil.
Spindle cooling mechanism of the machine tool described.