JPS6116575B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a machine such as a machine tool or a dimension measuring device having a structure in which a movable body moves along a sliding guide surface, and particularly to a machine equipped with a load compensation guide surface.

In general, two types of sliding surface methods have been employed for slidingly guiding a movable object, such as a work table, along a guide surface provided on a base of a machine tool or a measuring instrument. In other words, (i) a dynamic pressure sliding method in which the base guide surface and the moving object are brought into direct contact with each other via lubricating oil, etc.; This is a static pressure sliding method in which a pressure fluid is sent in and the load is supported by the static pressure of the pressure fluid without direct contact.

Of the two methods mentioned above, the dynamic pressure sliding method has a large sliding resistance, which changes depending on the magnitude of the load from the moving object, and also causes the occurrence of stake slip, which deteriorates mechanical accuracy. .

On the other hand, in the static pressure sliding method, as shown in FIG. In this method, the movable body 9 is completely floated from the guide surface with a clearance h, and slides in a state where the solid friction force is zero. In this case, the moving body 9
When the applied load acting on increases by Δw, the clearance h decreases by Δh. As a result, the back pressure increases, so the pressure in the chamber 3 of the pressure regulating throttle valve device 2 increases, the diaphragm 4 bulges upward, and the clearance Go increases. Therefore, since the opening degree of the throttle 5 increases, the pressure of the pressure fluid supplied to the movable body 9 increases, and the clearance h-Δh returns to the original h again. In addition, the diaphragm 4 used in the pressure regulating throttle valve 2 in the conventional static pressure sliding method described above directly adjusts the throttle opening, so a metal membrane such as stainless steel is generally used, and the initial clearance Go is A structure using a spring 6 and an adjustment screw 7 is adopted. In such a static pressure sliding system, it is difficult to recover the pressure fluid, especially when it is a liquid, and there is also the problem that heat is generated on the sliding surface due to the viscosity of the liquid. When the pressure fluid is a gas, the rigidity of the sliding portion 10 is poor, and both liquid and gas have a disadvantage in that the ability to damp vibrations of the moving body 9 is poor.

As mentioned above, the conventional dynamic pressure sliding method and the static pressure sliding method each have their drawbacks, and as part of resolving these drawbacks, pressure fluid is applied from the outside to the sliding surface between the guide surface and the movable object, which is formed on the base object. part of the weight of the moving body and the load acting on the moving body is supported by the static pressure of the pressure fluid, and the rest is supported by direct contact between the moving body and the base object. , a machine equipped with a load compensating guide surface that has less stick slip and exhibits high rigidity has already been proposed. In this case, the contact pressure between the sliding surfaces that occurs depending on the load acting on the guide surface is detected, and according to this contact surface pressure, pressure fluid is sent to the extent that the sliding surfaces are in contact with each other. It is impossible to reuse the pressure regulating throttle valve used in the static pressure sliding method shown in Fig. 1, because the change in back pressure of the pressure fluid is minute and cannot compensate for the load by itself. Therefore, in order to amplify the change in back pressure and convert it into an increase in the pressure of the pressure fluid, the supply hole for the back pressure detection fluid is provided independently of the pressure fluid supply hole for load compensation, for example, on the sliding surface of the moving body. A configuration is adopted in which the detected change in back pressure is amplified by a pressure amplification valve type pressure control device and sent to the compensation pressure fluid supply hole. The structure of the pressure control device in this case is disclosed in Japanese Patent Application No. 53-35202 filed by the present applicant.
The pressure amplification factor is related to the spring force of a spring provided in the pressure control device and the spring force of a diaphragm in the back pressure detection chamber. In addition, the output characteristics of the pressure fluid for load compensation vary slightly due to changes in the clearance between the spool valve end and the valve seat in the pressure amplification section of the device, and the shape of the spool valve end and the valve seat. However, it is difficult to manufacture a large number of pressure control devices with the same pressure amplification factor and output characteristics. Moreover, when the weight of a moving object and a portion of the load acting on the moving object are supported by the static pressure of a pressurized fluid, it is necessary to arrange multiple pressure control devices on the actual sliding surface of the machine. However, a mismatch in pressure characteristics or a mismatch in pressure amplification factors presents a disadvantage in that the support of the moving body by static pressure becomes non-uniform.

It is therefore an object of the invention to remedy the above-mentioned drawbacks of the previously proposed machines with load-compensating guideways.

Another object of the present invention is to provide a structure capable of manufacturing a large number of pressure control devices with matching performance such as pressure amplification factor and output characteristics, and to provide a structure including the improved load compensation guide surface as described above. Our objective is to provide a pressure control device that is essential for machines that require That is, the present invention includes a guide surface provided on a base of a machine, a movable body that moves along the guide surface, and a drive device that moves the movable body, and the present invention reduces the load acting on the movable body. In a machine equipped with a load compensation guide surface configured to compensate for a constant load acting on a contact surface between the movable body and the guide surface regardless of changes, A plurality of sets of a back pressure detection hole surrounded by a pressure fluid supply groove and a relief groove opened to atmospheric pressure and a lubricating oil supply groove are provided in an alternating arrangement on either side, and the pressure fluid Pressure fluid is supplied from the supply groove between the movable body and the guide surface, and the pressure fluid applies a force that tends to levitate the movable body to the contact surface between the movable body and the guide surface. a pressure fluid supply device that supplies a pressure fluid such that the pressure fluid is smaller than a load acting vertically; and a pressure fluid supply device that supplies a back pressure detection fluid between the moving body and the guide surface from the back pressure detection hole and the movement of the a displacement detection device that detects a minute displacement of the movable body in a direction perpendicular to the guide surface caused by a change in load acting perpendicularly to a contact surface between the body and the guide surface as a change in back pressure; a pressure control device that controls the pressure of pressure fluid supplied between the movable body and the guide surface according to a positional change detected by the device, the pressure control device including a housing; a first chamber for guiding the back pressure detection fluid supplied to the back pressure detection fluid supply hole; and a pressure opposing the pressure of the back pressure detection fluid supplied to the back pressure detection fluid supply hole. a diaphragm with a small spring constant that isolates the second chamber from which a fluid is guided; providing a spool valve to be adjusted and a passage that guides the fluid whose pressure has been adjusted by the spool valve to an end surface of the spool valve opposite to the diaphragm, and supplying lubricating oil from the lubricating oil supply groove to the contact surface, The present invention is characterized in that the frictional force at the contact surface between the movable body and the guide surface is maintained at a constant value. Hereinafter, the present invention will be explained in detail with reference to the attached FIGS. 2a to 2e and 3 to 6.

FIGS. 2a to 2e are enlarged views of the contact surface between the movable body 9a and the guide surface 8a. Generally, one of the contact surfaces between the movable body 9a and the guide surface is formed by a hardened and ground surface, and the other is formed by a scraped surface. Here, a case will be considered in which the contact surface of the movable body 9a is a scraped surface, and the guide surface 8a is formed as a hardened and ground surface. When the contact surface is enlarged, as shown in the figure, the guide surface 8a that has been hardened and ground is almost flat and has a hardened surface, and the surface of the movable body 9a that has been scraped has many irregularities. There is. Mobile body 9a
Guide surface 8a for the own weight of the body and the load acting on the moving body 9a
The convex portion of this unevenness is elastically compressed and deformed between it and the guide surface 8a by the component in the direction perpendicular to the guide surface 8a.
They will touch each other with a certain area. The above-mentioned dynamic pressure sliding method is a method of sliding while supporting the load only by direct contact between the convex portion and the guide surface 8a, as shown in FIG. As shown in the figure, a pressure fluid exists between the unevenness on the contact surface of the movable body 9a and the guide surface, and the movable body is completely levitated by the static pressure, and the convex portion and the guide surface 8a are directly connected to each other. This is a method that allows sliding without significant contact. In contrast, in the present invention, the force that tries to levitate the movable body 9a by the pressure fluid supplied between the movable body 9a and the guide surface 8a, that is, the static pressure, is caused by the weight of the movable body 9a and the In this method, pressure fluid is supplied so that the component of the load acting on the guide surface 8a in the direction perpendicular to the guide surface 8a is smaller than that of the load acting on the guide surface 8a to cause the guide surface 9a to slide. That is, this is a system in which the weight of the movable body 9a and the component of the load acting on the movable body in a direction perpendicular to the guide surface are supported by direct contact between the static pressure of the pressure fluid and the guide surface 9a. This is shown in Figures 2b to 2d.
As shown in the figure. In FIG. 2b, since the static pressure of the pressure fluid is large, the supporting force due to direct contact is small, and the amount of elastic deformation δ ₁ of the convex portion on the contact surface of the moving body 9a is
is small, but as the static pressure becomes smaller as shown in Figures 2c and 2d, the supporting force due to direct contact increases, and the elastic deformation amounts of the convex portions δ ₂ and δ ₃
It's getting bigger and bigger. When the static pressure of the pressure fluid becomes zero, it becomes the dynamic pressure sliding method described above, and since the entire load is supported only by direct contact, the amount of elastic deformation of the convex part is even larger δ
It becomes ₄ . As shown in Figures 2b to 2d, the component of the weight of the moving body and the load acting on the moving body in the direction perpendicular to the guide surface is calculated by combining the static pressure of the pressure fluid, the moving body, and the guide surface. A case where the method of sliding while supporting by direct contact is applied to an actual machine will be described below.

FIG. 3 is a diagram schematically showing a load compensation guide surface according to the present invention, which is installed in a machine such as a machine tool or a measuring instrument. The figure shows a case in which the movable body 13 slides along the guide surface of the base 11, and the sliding surface of the movable body 13 has a pressure fluid supply groove 15 and a pressure fluid supply groove 15 communicating with the supply groove 15. A pressure fluid supply passage 17, a displacement detection fluid supply hole 19 for detecting minute displacement of the movable body 13 in a direction perpendicular to the guide surface of the base 11 by a change in back pressure, and Open relief groove 23. Displacement detection fluid supply passage 21 communicating with the supply hole 19 and relief groove 2
3 and a passage 25 communicating with the atmosphere is formed. Pressure fluid whose pressure has been amplified by a pressure control device 29 (described later) is supplied from a pressure fluid generation device 51 to the pressure fluid supply groove 15 described above through a passage 17. 57 is a pressure gauge that indicates the pressure value of this pressure fluid. Further, a desired pressure value is transmitted from the pressure fluid generator 51 through the pressure regulating valve 55 and the passage 21.
The displacement detection fluid whose pressure is regulated to Pso is supplied to the displacement detection fluid supply hole 19 . The pressure control device 29 has a housing 31 in which a chamber 3 is partitioned by a diaphragm 37.
3 and 35 are formed, the chamber 33 has an opening 33a, and the chamber 35 has an opening 35a. In addition, the upper end of the housing 31 is connected to the diaphragm 3.
A spool valve 39 fixed to the hole 49 is provided to be able to slide linearly in the hole 49, and a chamber 49a formed by the wall surface of the hole 49 and the hole bottom surface is formed below the lower end surface 45 of the spool valve 39. has been done. The spool valve 39 has a constricted small diameter portion 41 in the middle portion, and a chamber 47 is formed between the constricted small diameter portion 41 and the wall surface of the hole 49.
It communicates with the chamber 49a via a communication path 43 formed in 9. Pressure fluid delivery passage 47b from chamber 47
Pressure fluid is supplied to the movable body 13 through the .
Further, when the pressure fluid flows into the chamber 47 through the pressure fluid introduction passage 47a formed in the housing 31,
A structure is provided in which the spool valve 39 changes the aperture opening degree. As for this structure, in this embodiment, a tapered portion 41a is formed in the constricted small diameter portion 41 of the spool valve 39 so that the aperture opening degree does not change abruptly in response to a minute displacement of the spool valve 39. is not limited to a tapered shape, but may be formed in a stepped shape. In addition, rooms 33 and 35
It is desirable that the diaphragm 37 that partitions the diaphragm 37 be formed of a thin rubber film having an extremely small spring constant. Stoppers 50a and 5 prevent excessive displacement of the spool valve 39 to protect the diaphragm 37.
0b are provided in the housing 31 near both ends of the spool valve 39. Further, the fluid at the pressure Ps ₁ in the chamber 35 and the fluid at the pressure Pr in the chamber 47 are connected to the spool valve 3.
An annular groove 40 and a passage 40a for opening to atmospheric pressure are provided in the fitting part of the spool valve 39 and the housing 31 so that the fitting part of the spool valve 39 and the housing 31 does not enter the fitting part and interfere with each other. The design is designed to actively release fluid that has entered the joint to the outside.

The pressure fluid supply device described in the claims refers to the pressure fluid generation device 51 mentioned here, piping for supplying pressure fluid to the moving body 13, etc., and the displacement detection device refers to These include the formed displacement detection fluid supply hole 19 and piping that guides the fluid with the back pressure Pso to the chamber 33 of the pressure control device 29.

In the pressure control device 29 having the above-described structure, pressure fluid regulated to a pressure value Ps ₁ is supplied from the pressure fluid generation device 51 to the chamber 35 via the pressure regulating valve 53 and the opening 35a, and on the other hand, In the chamber 47, a pressure fluid having a pressure value Po adjusted appropriately from the pressure fluid generation device 51 is supplied to the pressure fluid introduction passage 47a.
Supplied via. At this time, the pressure fluid supplied to the chamber 47 is subjected to a throttling effect by the spool valve 39, and becomes the pressure value Pr, which increases the pressure fluid to the pressure fluid delivery passage 4.
7b, the pressure gauge 57, and the pressure fluid supply passage 17 to the pressure fluid supply groove 15. room 4 at the same time
The pressure fluid (pressure value Pr) No. 7 also flows into the chamber 49a via the small diameter communication passage 43 of the spool valve 39. Further, as described above, the displacement detection fluid regulated to the desired pressure value Pso is supplied to the displacement detection fluid supply hole 19.
At the same time, the fluid having this pressure value Pso is branched and also supplied to the chamber 33 through the opening 33a.

The operation of the load compensation guide surface between the base 11 and the movable body 13, which are supplied with pressure fluid via the pressure control device 29, will be described below.

First, as an initial state setting, what percentage of the weight W of the movable body 13 is received by the static pressure of the pressure fluid and what percentage is received by the direct contact force between the movable body 13 and the guide surface of the base 11 is determined in advance. decide. For example, assuming that the above two percentages are 50% and 50%, respectively, the pressure fluid supply groove 15
The pressure value Pr is determined by calculation so that the product of the surrounding effective pressure receiving area Ap and the pressure value Pr of the pressure fluid, that is, the static pressure due to the pressure fluid, becomes 1/2 of the weight W of the moving body 13. Next, the position of the spool valve 39 is determined by adjusting the pressure regulating valve 55 so that the indicated value of the pressure gauge 57 becomes the value determined by this calculation. The balance of forces within the pressure control device 29 when the initial state is set in this way is expressed by the following equation (1).

Pso・A ₁ = Ps ₁・A ₂ + Pr・A ₃ ...(1) Here, A ₁ is the diaphragm 37 in the chamber 33
The effective area of the upper surface, A ₂ is the effective area of the lower surface of the diaphragm 37 in the chamber 35 (A ₂ is the effective area of the spool valve 39
A is smaller than ₁ by the cross-sectional area of . ), A ₃ is the effective area of the lower end surface of the spool valve 39. Also diaphragm 3
The spring constant of 7 is small, so ignore the spring force term. Furthermore, since the supply pressure Pr is set so that the static pressure due to the pressure fluid is 1/2 of the weight W of the moving body 13, the relationship between Pr, W, and Ap is expressed by the following equation (1)'. .

Pr・Ap=1/2W...(1)' Now, assuming that a load 27 (weight Δw) is further applied to the moving body 13 as shown in FIG. 4, the moving body 13 and A minute displacement occurs in a direction perpendicular to the guide surface of the base 11 due to elastic deformation of the convex portion of the contact surface. As a result, the back pressure of the displacement detection fluid is Pso + Δ
Become a Pso. Therefore, the pressure in the chamber 33 is also increased to the same value, so the diaphragm 37 is pushed down as shown in the figure, and the spool valve 39 fixed to the diaphragm 37 is also lowered, causing pressure fluid to flow into the chamber 47. Aperture aperture increases. Therefore, the pressure of the pressure fluid inside the chamber 47 increases, and as a result, the pressure of the pressure fluid supplied to the pressure fluid supply groove 15 of the moving body 13 increases to become Pr+ΔPr. Therefore, the balance of forces within the pressure control device 29 is expressed by the following formula:
It is shown in (2).

(Pso + ΔPso)・A ₁ = Ps ₁・A ₂ + (Pr+ΔPr)・A ₃ ...(2) When additional load ΔW is applied, the relationship between ΔPr, ΔW, and Ap is expressed by the following equation (2)'. shown.

(Pr+ΔPr)Ap=1/2W+ΔW...(2)′ Therefore, from the above equation (1)′, ΔPr・Ap=ΔW…(2)″
becomes.

Substituting the above equation (2) into equation (1), ΔPr=A ₁ /A ₃・ΔPso ...(3) From equation (3), the pressure control device 29 calculates the small back pressure change ΔPso as A ₁ /A ₃ This means that the pressure has been amplified twice, creating a pressure of ΔPr that is sufficient to compensate for the load of Δw. Therefore, when the weight Δw of the load 27 acts as an increase on the own weight W of the moving body 13, Δ
By compensating for the pressure increase Pr, the load received by the direct contact force of the guide surface of the base 11 can still be maintained at a level of 1/2 of W, which is the same as the initial setting state. In other words, even if the load acting on the movable body 13 increases or decreases, the load received by direct contact between the movable body 13 and the guide surface of the base 11 remains unchanged due to the function of the pressure control device. Therefore, the frictional force when the moving body 13 slides is also always maintained at a constant value. What can be noted here is that the pressure amplification factor of the pressure control device 29 is
A ₁ /A ₃ , that is, it is uniquely determined by the ratio of the effective area of the upper surface of the diaphragm 37 to the effective area of the lower end surface of the spool valve 39. This allows the amplification factor to be easily determined at the design stage. It has a feature that it is not affected by the spring force of the adjustment spring or the spring force of the diaphragm, unlike conventional pressure control devices.

Next, an example in which the above-described structure of the compensation guide surface is applied to the X-axis sliding surface of a machining center, that is, the sliding surface between the saddle and the work table will be described with reference to FIG.

Figure 5 shows two scratched sliding surfaces 6.
1, 63 and a low-level portion 65 in between.
FIG. 3 is a plan view showing the upper surface portion of the saddle.
A work table (not shown) slides along the two sliding surfaces 61 and 63 in the X-axis direction.
Now, the sliding surfaces 61, 63 have pressure fluid supply grooves 67a, 67b, 67c, 67d, 67e, 6, respectively.
7f, 67g, 67h are located at eight locations, displacement detection fluid supply holes and relief grooves 69a, 69b, 69c, 6
9d, 69e, and 69f are properly arranged with respect to the pressure fluid supply grooves, and oil grooves 7 for lubricating oil supply are provided at six locations.
1,73 are distributed in eight locations. The work table sliding surface facing the two rows of sliding surfaces 61 and 63 is formed into a hardened and ground flat surface. Six combinations 67a, 69a, 67b and 67c and 69b of pressure fluid supply grooves, displacement detection fluid supply holes, and relief grooves provided at the left end, center, and right end of each sliding surface 61, 63, 67d and 69c, 67e and 69d, 67
A total of six pressure control devices 29 (FIGS. 3 and 4) are used, one each for f, 67g, 69e, 67h and 69f.

Now, in order to confirm the effect of using the load compensating guide surface according to the present invention in sliding between the saddle sliding surface and the work table, the following experiment was conducted. That is, the initial setting is such that the work table's own weight of 520 kg is supported by the static pressure of the pressure fluid of 260 kg, and by the direct contact force between the work table and the saddle sliding surface of 260 kg, and the pressure fluid is supported by the pressure fluid generator 51. (see Figures 3 and 4) to the pressure control device 29 (see Figures 3 and 4).
Figure 4) Using air of Po = 5Kg/ ^cm2 , the sliding frictional resistance when workpieces of various weights are placed on the worktable, that is, the drive torque of the table feed motor, is calculated as the load according to the present invention. Actual measurements were made and compared between cases with and without compensation guide surfaces. The comparison results are shown in FIG.

As is clear from FIG. 6, when the load compensating guide surface according to the present invention is provided, the sliding frictional resistance becomes approximately constant regardless of the load acting on the work table. Therefore, the positioning accuracy of the work table itself is good, and since there is direct contact between the work table and the saddle sliding surface, there is almost no reduction in dynamic rigidity. In addition, pressure fluid supply groove,
It has multiple fluid supply holes for displacement detection and pressure control devices, so even when a load is applied to the edge of the work table, the load can be compensated to ultimately keep the work table in a horizontal position. be able to.

Furthermore, since the pressure control device according to the present invention uses a diaphragm with a very small spring constant,
The amplification factor can be uniquely determined only by the dimensions of the diaphragm and spool valve. Therefore, it has the advantage of being able to design an accurate device at the device design stage, and even when using multiple pressure control devices, uniform characteristics can be obtained among them, and it is also easier to use than conventional pressure control devices. It has the advantage of being simpler in structure than automatic pressure regulating throttle valves and pressure control devices, so it can be expected to be more compact.
Moreover, it has excellent responsiveness. Using air as the pressure fluid in this experiment also has the advantage of eliminating the need for recovery. The minute displacement due to the elastic deformation of the convex portion on the contact surface was measured by loading the maximum load on an actual machining center, and found that it was at most 1 to 2 microns. Therefore, the precision of the machine is hardly affected.

[Brief explanation of the drawing]

Fig. 1 is a schematic mechanical diagram showing a conventional hydrostatic sliding type pressure fluid control system, and Figs. 2a to 2e show a conventional hydrostatic sliding type, a dynamic pressure sliding type, and a sliding type according to the present invention. An enlarged view of the compared sliding contact surfaces, FIG. 3 is a schematic mechanical diagram schematically showing an embodiment of a machine equipped with a load compensating guide surface according to the present invention, and FIG. FIG. 5 is a similar schematic mechanical diagram for explaining the action in the case where the load compensation guide surface according to the present invention is applied to the sliding part between the saddle sliding surface and the work table of a machining center. FIG. 6 is a plan view showing an embodiment of the configuration of the saddle sliding surface, and FIG. 6 is a graph showing the effects of the present invention in comparison with the conventional one. DESCRIPTION OF SYMBOLS 11... Base, 13... Moving body, 15... Pressure fluid supply groove, 19... Fluid supply hole for displacement detection, 29... Pressure control device, 31... Housing, 33, 35... Chamber,
37...Diaphragm, 39...Spool valve, 51...
Pressure fluid generator, 53, 55...pressure control valve.

Claims (1)

[Scope of Claims] 1. A machine comprising a guide surface provided on a base of a machine, a movable body that moves along the guide surface, and a drive device that moves the movable body, the movable body and the guide surface The load applied to the guide surface from the movable body is supported by the supporting force of both the contact pressure and the levitation force due to fluid pressure at the contact surface with the movable body, and the contact surface is supported regardless of changes in the load acting on the movable body. In a machine equipped with a load compensating guide surface that increases or decreases the levitation force according to fluctuations in the load in order to keep the load borne by the pressure constant, an opposing contact surface between the movable body and the guide surface A plurality of grooves for supplying pressure fluid on one side, a back pressure detection hole surrounded by a relief groove open to atmospheric pressure, and a lubricating oil supply groove supplying lubricating oil to the contact surface. A pressure fluid is supplied between the movable body and the guide surface from the pressure fluid supply groove, and a force that attempts to levitate the movable body by the pressure fluid is applied to the movable body and the guide surface. a pressure fluid supply device that supplies pressure fluid so as to be smaller than a load acting perpendicularly to a contact surface with the back pressure detection fluid between the movable body and the guide surface from the back pressure detection hole; a displacement detection device that detects a minute displacement in a direction perpendicular to the guide surface of the movable body caused by a change in load acting perpendicularly to a contact surface between the movable body and the guide surface as a change in back pressure; and a pressure control device that controls the pressure of the pressure fluid supplied between the movable body and the guide surface according to the amount of displacement detected by the displacement detection device, and the pressure control device includes a housing. and a first chamber 33 for guiding the back pressure detection fluid supplied to the back pressure detection fluid supply hole in the housing, and a first chamber 33 for guiding the back pressure detection fluid supplied to the back pressure detection fluid supply hole A diaphragm with a small spring constant that separates the pressure from a second chamber 35 that introduces a fluid having an opposing pressure; A spool valve for adjusting the pressure of the pressurized fluid and a passage for guiding the fluid whose pressure has been adjusted by the spool valve to an end surface of the spool valve opposite to the diaphragm are provided, and the movable body and the guide surface are in contact with each other. A machine equipped with a load compensating guide surface, which is characterized in that the frictional force on the surface is maintained at a constant value. 2. The pressure fluid supply device according to claim 1, wherein the pressure fluid supply device is configured to include a pressure regulating valve that can adjust and change the pressure of the pressure fluid supplied between the movable body and the guide surface. Machines with load-compensating guideways. 3. A machine equipped with a load compensation guide surface according to claim 1 or 2, wherein the pressure fluid is formed by pressurized air.