JPH07106053B2 - Linear moving device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a linear moving device in which a slider linearly moves by a linear motor.

[Conventional technology]

In precision machining or precision measurement, in order to make the slider travel accurately, a non-contact static pressure air bearing, which has less frictional force during movement than a rolling guide, is used.

FIG. 5 is a perspective view of a moving device using this static pressure air bearing. As shown, the slider 1 is attached to the slide shaft 2.
Is moved linearly in a non-contact state by a static pressure air bearing. The slider 1 is moved by the feed screw 51 and the motor.
52 and done by. That is, the feed screw 51 is screwed into the nut 53 attached to the slider 1, and the rotational movement is converted into a linear movement, whereby the slider 1 moves linearly. In the figure, 54 is a bearing that supports both ends of the feed screw 51. However, in this feed screw method, heat and vibration of the motor 52 are transmitted to the slider 1 via the feed screw 51, so that the slider 1 is thermally deformed or vibrates. Further, if the bearing 54 that supports the feed screw 51 is loose or if the parallelism between the feed screw 51 and the slide shaft 2 is disturbed, it is difficult to perform highly accurate movement due to external fluctuation when the slider 1 moves. There is.

In order to eliminate such a drawback, a linear moving device for moving a slider in a non-contact state by using a linear motor has been conventionally proposed (Japanese Utility Model Application No. 61-10078 and Japanese Patent Application No. 62-1).
16142).

FIG. 6 shows a linear moving device disclosed in Japanese Utility Model Laid-Open No. 61-10078. A bobbin 61 around which a coil 7 is wound is attached to the slider 1. The slide shaft 2 is provided so as to penetrate the bobbin 61. Magnets 8 are provided on both sides of the slide shaft 2, and a linear motor 78 is configured by the coil 7 and the magnet 8. Further, a constant space (not shown) is formed between the bobbin 61 and the slide shaft 2. By supplying the air 23 from the air pipe 24 to the space, the bobbin 61 is supported in a non-contact state. It has become so. Reference numeral 62 is a lead wire for supplying electric power to the coil 7.

Furthermore, FIG. 7 [perspective view] and FIG. 8 ([II-II line sectional view])
Is a linear moving device in Japanese Patent Application No. 62-116142 previously proposed by the present applicant.

As shown in the figure, the slider 1 is formed in a rectangular closed cross-sectional shape,
The slide shaft 2 is inserted inside. 3 is slider 1
This is a static pressure air bearing portion provided inside, and this bearing portion 3
The slider 1 is supported by the slide shaft 2 in a non-contact state via. A coil 7 is provided in the longitudinal direction of the slide shaft 2 (a direction penetrating the paper surface in FIG. 8), and a magnet 8 is installed so as to correspond to the coil 7. A linear motor 78 is formed by the core 6, the coil 7 and the magnet 8. With such a structure, when the coil 7 is energized, a magnetic force acts and the slider 1
Can move the slide shaft 2 in a non-contact state.
With this structure, a linear moving device can be realized in an extremely compact manner.

[Problems to be Solved by the Invention]

However, in the conventional device shown in FIG. 6, since the moving slider 1 is provided with the coil 7, the slider 1
Is large and heavy. Further, the lead wire 62 for supplying electric power to the coil 7 becomes an obstacle, and the running accuracy of the slider 1 is impaired. Furthermore, the coil 7
Due to the heat generation, it is not possible to secure a gap between the bobbin 61 and the slider shaft 2, and there are drawbacks such as high cost due to the use of a large number of magnets 8.

The conventional apparatus shown in FIGS. 7 and 8 solves many of the above drawbacks and difficulties. That is, the weight of the slider 1 can be reduced by disposing the magnet 8 on the slider 1 side, the cost can be reduced by reducing the number of magnets 8, and the running accuracy can be improved without the lead wire. But this 7th
In the conventional device shown in FIG. 8 and FIG. 8, since the coil 7 of the linear motor 78 which is the main heat generating portion is directly attached to the slider shaft 2, there are many problems that the slider shaft 2 is deformed by heat. Had. There have been problems such as deterioration in running accuracy due to deformation due to heat and changes in the clearance in the static pressure air bearing 3.

In view of this, the present invention provides a linear movement device capable of highly precise movement in which glory due to heat is removed while maintaining the features that the conventional device shown in FIGS. 7 and 8 has a simple structure and is small in size. , And its purpose.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the linear moving device according to the present invention has a slider supported by a static pressure air bearing in a non-contact state with respect to the slide shaft by a linear motor provided between the slide shafts. In a device that moves in the axial direction, the linear motor has a structure in which the coil portion and the slide shaft are thermally isolated, and the heat generated by the cooling pipe and the coil for maintaining the static pressure air bearing portion of the slide shaft at a constant temperature. It is characterized in that it is provided with a tube for cooling the magnet, and is characterized in that the magnet portion and the slider are thermally cut off.

Furthermore, one slide shaft is cooled by the refrigerant,
Since the other slider is cooled by the press-fitted air, the refrigerant and the air are supplied to keep the temperature of the slider and the slide shaft constant as much as possible so as not to cause a temperature mismatch between the two sliders. The linear moving device has a static pressure air bearing unit in which the temperature of the slide shaft and the slider is kept constant by making the temperature of the air, which has a small heat capacity and is susceptible to temperature fluctuations, constant with a refrigerant having a large heat capacity and a small temperature fluctuations. The gap between is constant.

Then, if the temperature of both the slide shaft and the slider fluctuates, the gap between the hydrostatic air bearing portions shown in FIG. 8 changes, and the load capacity and bearing rigidity also change.

[Work]

In the present invention, a linear motor is formed by the coil and the magnet, and the slider moves linearly by energizing the coil. Further, the static pressure air bearing supports the slider in a non-contact state with the slide shaft by supplying air from the air supply passage. With such a structure, the heat generated in the coil is not transmitted to the slide shaft, and in order to keep the temperature of the static pressure air bearing surface constant, the cooling pipe is cooled by elongating the temperature-controlled refrigerant.

Furthermore, according to the present invention, an air pipe for supplying air and a cooling pipe for passing a refrigerant are integrated and supplied to a linear moving device, so that a short time temperature fluctuation of air such as a temperature time constant of hundreds of milliseconds can be achieved by several hundreds. It is possible to suppress with a refrigerant having a temperature time constant such as seconds.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to the illustrated embodiments.

FIG. 1 is a perspective view of an embodiment of the present invention, and FIG. 2 is its II-
It is a II sectional view.

The slider 1 is formed in a rectangular closed cross section having a hollow portion, and a slide shaft 2 penetrates the inside of the slider 1.
A material having a low specific gravity and a low thermal expansion coefficient (for example, a ceramic or plastic material) can be applied to the slider 1, which makes it lightweight and has a small thermal deformation. The slide shaft 2 is formed in an “I” shape in cross section, and a predetermined air gap is formed between the projecting upper and lower side portions and the slider 1 facing it, thereby forming the hydrostatic air bearing 3. ing.

When the air 23 is press-fitted from the air supply port 5 that supplies the air 23, the slider 1 is supported by the hydrostatic air bearing 3 in a non-contact state with the slide shaft 2.

Furthermore, the linear motor coil 7 and the core 6 are attached to both side surfaces of the slide shaft 2 via the heat insulating portion 10a. The heat insulating portion 10a is formed of a material having low thermal conductivity, a vacuum layer air layer, or the like.

In the case of a low heat conductive material, it is optimal to make it as thick as possible, in the case of a vacuum layer it is a material having a low emissivity, and in the case of an air layer, its thickness is optimally 2 to 5 mm.

By the way, in the case of a vacuum layer, for example, a sealed heat-insulating space is formed between the core 6 and the slide shaft 2, and the air in this space is extracted to create a vacuum. It suffices to provide and fix it on it, and the contact area between the core 6 and the slide shaft 2 should be as small as possible.

Further, in the case of an air layer, a small seat is provided on the slide shaft 2 and the core 6 is fixed thereon, but it is not necessary to form a closed heat insulating space.

Corresponding to the coil 7, a magnet (permanent magnet) 8 is attached to the slider 1 via a predetermined gap via a heat insulating portion 10b. The condition of this heat insulating part 10b is that of the heat insulating part 10a.
It is the same as the condition of.

Further, a cooling pipe 9b is provided near the air bearing portion 3 of the slider shaft 2.
Is installed, and the cooling pipe 9 is installed in the core portion 6 of the linear motor 78. And the cooling pipe 9a and the cooling pipe 9b
Are connected at one end of the slide shaft 2. Further, the cooling pipe 9a and the cooling pipe 9b are connected to the circulation means of the refrigerant 13 and the temperature control means, and constitute a closed loop as a whole (shown in FIG. 3).

Next, the operation will be described.

Air 23 is press-fitted from the air supply zone 5 and the static air bearing 3
The slider 1 is supported on the slide shaft 2 in a non-contact state. When the coil 7 attached to the slide shaft 2 is energized in this state, the linear motor 78 is activated and the slider 1 linearly moves along the slide shaft 2. In this case, it is indispensable for realizing highly accurate motion that the gap between the static pressure air bearing 3 and the slide shaft 2 are not deformed by the heat generated by the linear motor 78.

For example, the refrigerant 13 having a constant temperature by the temperature control means of the refrigerant 13 such as the refrigerant cooling device 11 shown in FIG. 3 first passes near the static pressure air bearing portion 3 of the slide shaft 2. The temperature of the static pressure air bearing portion 3 is kept constant to prevent a change in thermal expansion. Since the slide shaft 2, the coil 7 of the linear motor 78, and the core 14 are thermally insulated by the heat insulating portion 10a, the slide shaft 2 and the static pressure air bearing portion 3 can be easily kept at a constant temperature. Slide shaft 2
The cooling medium 9 whose temperature is kept constant by the cooling pipe 9b is connected to the cooling pipe 9a at one end of the slide shaft 2 so as to cool the coil 7 which is the heat source of the linear motor 78.
Flowing through.

The refrigerant 13 that has cooled the coil 7 and has increased in temperature returns to the refrigerant cooling device 11 that circulates the refrigerant shown in FIG. 3 and is temperature-controlled, and again forms a closed loop to the cooling pipe 9b.

In addition, the magnet 8 slightly heated by the heat of the coil 7
Also, due to the effect of the heat insulating portion 10b, the temperature rise and thermal deformation of the slider 1 are not caused.

Next, another embodiment of the present invention is shown in FIG. 3 [a block diagram showing the configuration of the equipment of the circuit] and FIG. 4 [a sectional view taken along the line AA of the integrated pipe in which the cooling pipe and the air pipe are joined]. Shown.

In this other embodiment, the air pipe 24 for supplying the air 23 to the slider 1 is branched from the integrated pipe 12 in which the air pipe 24 and the cooling pipe 14 are integrated in the vicinity of the linear moving device.

The refrigerant 13 having a constant temperature by the refrigerant cooling device 1 is integrated with the air pipe 23 to keep the air 23 at a constant temperature up to the branch point near the linear moving device, for example, FIG. 4 (a).
The air 23 which flows through the inside of the integral pipe 12 forming the double pipe and is press-fitted by the refrigerant 13 is made to have the same temperature as the refrigerant 13. After that, the refrigerant 13 cools the slider shaft 2, returns to the refrigerant cooling device 11 by passing through the cooling pipe 14, and cools the refrigerant 13 whose temperature has risen again by the refrigerant cooling device 11.

On the other hand, the air 23 is sent from the air supply device 21 to the integrated pipe 12 through the air pipe 24 and is branched from the cooling pipe 14 as described above.
It is supplied to the slider 1 via 24.

As shown in FIG. 4 (a) AA sectional view, the integral pipe 12 is composed of a portion through which air 23 is passed inside and a double pipe through which a liquid medium (refrigerant 13) is passed through the outer peripheral portion.

Further, FIG. 4 (b) is an integral pipe in which an air pipe and a cooling pipe are formed adjacent to each other.

In any case, the joint portion between the air pipe 24 and the cooling pipe 14 is made of a good heat conductor, and the outer covering portion of the integrated pipe 12 is formed of a heat insulator.

〔The invention's effect〕

As described above, according to the present invention, the heat generation portion of the linear motor, the slide shaft, and the slider are thermally cut off, so that thermal deformation that deteriorates motion accuracy and change in the gap of the hydrostatic air bearing can be prevented. Further, by flowing a coolant of a constant temperature to the slide shaft and further cooling the coil, the effect can be enhanced and the linear moving device capable of highly accurate movement can be obtained.

Further, in the conventional example, it is desirable to install two motors on the left and right of the slide shaft in order to make the thermal deformation symmetrical.
Although the cost is high, the present invention can eliminate the influence of heat, so that either one of the linear motors can be used and the cost can be reduced.

Further, according to the present invention, the refrigerant having a large heat capacity and the air having a small heat capacity are supplied to the linear moving device by an integrated tube, so that the temperature of the air supplied to the slider and the refrigerant supplied to the slide shaft are reduced. The temperatures can be matched. Therefore, the temperature of the slide shaft and the slider that form the hydrostatic air bearing becomes constant, the fluctuation of the gap disappears, and the load capacity and the bearing rigidity are stabilized.

In addition, the air supply device does not require a temperature control device for air which is usually required, and has a ripple effect of cost reduction.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention, and FIG.
II-II sectional view, FIG. 3 is a circuit configuration block diagram showing another embodiment, FIG. 4 is an A-A sectional view of the integrated pipe, and FIGS. 5 to 8 are explanatory views of a conventional example. 1 ...... Slider 2 ...... Slide shaft 3 ...... Static pressure air bearing 4 ...... Air supply path 5 ...... Air supply port 6 ...... Core 7 ...... Coil 8 ...... Magnet 9a, 9b ...... Cooling pipe 10a, 10b …… Blocking unit 11 …… Refrigerant cooling device 12 …… Integral pipe 13 …… Refrigerant 14 …… Cooling pipe 14a …… Cooling pipe wall 21 …… Air supply device 23 …… Air 24 …… Air pipe 24a …… Air pipe Wall 78 ... Linear motor.

Claims (2)

[Claims] 1. A slider that forms a moving portion, which is supported in a non-contact state by a hydrostatic air bearing on a slide shaft that forms a fixed portion, is formed by a linear motor provided between the slider and the slide shaft. A coil that constitutes the linear motor so as to move in the axial direction is provided in the axial direction of the slide shaft, a magnet facing the coil is provided in the slider, and air is press-fitted and supplied to the hydrostatic air bearing. In a linear moving device in which an air passage is formed in a slider, a slider near a slide shaft surface facing a surface of a static pressure air bearing surface is provided with a cooling pipe through which a refrigerant for keeping the temperature of the static pressure air bearing surface of a slide shaft constant. A cooling pipe, which is provided in the axial direction of the slider shaft in the shaft and cools the linear motor, is installed in the core around which the coil is wound. Linear movement device, characterized in that provided with the heat insulating member for thermally isolated between and both their inter or between the magnet and the slider shaft. 2. A slider, which constitutes a moving part supported in a non-contact state by a hydrostatic air bearing with respect to a slide shaft forming a fixed part, of a slide shaft by a linear motor provided between the slide shaft and the slide shaft. A coil that constitutes the linear motor so as to move in the axial direction is provided in the axial direction of the slide shaft, a magnet facing the coil is provided in the slider, and air is supplied to the static pressure air bearing. In a linear moving device in which a passage is formed in a slider, a cooling pipe through which a refrigerant that keeps the temperature of a static pressure air bearing surface of a slide shaft constant is provided with a slider shaft near a slide shaft surface facing the static pressure air bearing surface. An air pipe that is provided in the axial direction of the slider shaft inside and pressurizes air into the air supply passage of the static pressure air bearing, and the cooling pipe and the air pipe are provided on the slide shaft and the slider. Both bonded together gathered a good heat conductor at a portion of the route to that, the linear movement device being characterized in that so as also cooling air in the air tube.