CN108942655B

CN108942655B - Static pressure slide guide device and machine tool provided with same

Info

Publication number: CN108942655B
Application number: CN201810448059.5A
Authority: CN
Inventors: 大津雄太; 堀伸充; 野野山真
Original assignee: JTEKT Corp
Current assignee: JTEKT Corp
Priority date: 2017-05-19
Filing date: 2018-05-11
Publication date: 2021-10-19
Anticipated expiration: 2038-05-11
Also published as: DE102018111597A1; JP7062885B2; CN108942655A; JP2018194123A

Abstract

The invention provides a static pressure slide guide device and a machine tool provided with the same. A static pressure slide guide device (40) is provided with: a fixed body (19) having a first vertical guide surface (16a) and a second vertical guide surface (17 a); a movable body (14) having a first longitudinal sliding surface (14a1) and a second longitudinal sliding surface (14a 2); a fluid supply device (33); a pressure adjusting device (38); a hydrostatic bearing unit (34) which is supplied with fluid by a fluid supply device, and which forms a bearing stiffness (G) for the movable body, said bearing stiffness (G) corresponding to the size of a first gap (L1) between the first longitudinal guide surface and the first longitudinal slide surface, said bearing stiffness (G) being caused by a fluid pressure (P1) acting on the movable body and corresponding to the size of the first gap; and an urging force generation unit (35) that urges the movable body in the direction of the first vertical guide surface by being supplied with a fluid that has been regulated to a predetermined fluid pressure (P2a) by the pressure regulation device. The pressure regulating device regulates the pressure of the specified fluid to enable the size of the first gap to reach a set value.

Description

Static pressure slide guide device and machine tool provided with same

Technical Field

The present invention relates to a static pressure slide guide device and a machine tool provided with the same.

Background

Conventionally, there is a static pressure slide guide device that maintains two members including a movable body and a fixed body in a non-contact state, reduces friction when the two members move relative to each other, and increases support rigidity of the movable body with respect to the fixed body to realize stable relative movement, for example. For example, see Japanese patent laid-open Nos. 2013-221572, 57-57884, 2014-108503 and 2006-231483. Specifically, the hydrostatic sliding guide device is provided with a recessed Pocket (Pocket) on each of a pair of sliding surfaces, for example, a horizontal sliding surface and a vertical sliding surface of a movable body, which are one of facing surfaces of two members that move relative to each other.

Then, a fluid such as air or oil at a predetermined pressure is supplied to the pocket, and the fluid is ejected between the horizontal guide surface and the vertical guide surface of the fixed body and the horizontal sliding surface and the vertical sliding surface of the movable body, which face the guide surfaces, respectively, to form a gap. Thus, the two members are brought into a non-contact state, friction between the two members is reduced, sliding properties are improved, and support rigidity of the movable body with respect to the fixed body is ensured.

Further, at this time, there is a correlation between the size of the gap formed, the pressure of the fluid supplied to the pocket, and the support rigidity. Therefore, in order to ensure a desired support rigidity, it is necessary to manage the relationship between the fluid pressure and the gap between the vertical (longitudinal) guide surface and the vertical (longitudinal) sliding surface, in particular. In contrast, in japanese patent laid-open nos. 2013-221572, 57-57884, 2014-108503 and 2006-231483, a fluid at a predetermined fluid pressure is supplied from a fluid supply device (an oil pump or the like) through a predetermined supply path to each of left and right pockets provided on a pair of vertical (longitudinal) sliding surfaces, so as to secure a desired support rigidity.

However, in the supply path of Japanese patent laid-open No. 2013-221572, a fluid at a fixed pressure is supplied to both the one pocket and the other pocket via a fixed throttle valve. Therefore, if the desired support rigidity is to be ensured, adjustment by the fluid pressure is not possible, and therefore, it is necessary to strictly control the size of each gap. Therefore, it is necessary to accurately manage the dimension between the pair of guide surfaces of the fixed body and the dimension between the pair of sliding surfaces of the movable body during machining. In addition, when the movable body is assembled to the fixed body, the assembly work time increases because the assembly must be performed with high accuracy. This raises the cost.

In the supply path of jp 57-57884 a, a fluid at a fixed pressure is supplied to one pocket via a fixed throttle valve, and a fluid at a fixed pressure (discharge pressure) is directly supplied from an oil pump to the other pocket. In the supply path of japanese patent application laid-open No. 2014-108503, fluid is supplied to one pocket via an adjustable throttle valve in which the fluid pressure varies depending on the size of the gap, and fluid at a fixed pressure (discharge pressure) is directly supplied from an oil pump to the other pocket. In the supply path of japanese patent application laid-open No. 2006-231483, fluid is supplied to one pocket through an adjustable throttle valve that is adjusted to obtain a desired pressure regulation value, and fluid at a fixed pressure is directly supplied from an oil pump to the other pocket.

Thus, in Japanese Kokoku publication No. 57-57884, Japanese unexamined patent publication No. 2014-108503 and Japanese unexamined patent publication No. 2006-231483, a fluid at a fixed pressure is directly supplied from an oil pump to the other tank. Therefore, as shown in japanese patent laid-open No. 2013-221572, a sufficiently large fluid pressure can be applied to the gap on the at least one pocket side even without strictly managing the dimension between the pair of guide surfaces and the dimension between the respective sliding surfaces. In this way, a corresponding bearing stiffness can be achieved on the at least one pocket side. However, in this case, the control of the gap between the guide surface and the sliding surface cannot be performed. Therefore, the support rigidity having a high correlation with the clearance cannot be managed to an optimum value. Therefore, when it is desired to set the support rigidity to an optimum value, it is necessary to strictly control the dimension between the pair of guide surfaces and the dimension between the respective sliding surfaces, as in japanese patent application laid-open No. 2013-221572.

Disclosure of Invention

An object of the present invention is to provide a low-cost static pressure slide guide device and a machine tool including the static pressure slide guide device, which can easily ensure the support rigidity of a movable body with respect to a fixed body without setting the machining accuracy and the assembly accuracy to high accuracy.

A static pressure slide guide device according to an aspect of the present invention includes:

a fixed body having a first vertical guide surface serving as a reference surface and a second vertical guide surface having a normal direction opposite to the normal direction of the first vertical guide surface;

a movable body having a first longitudinal sliding surface facing the first longitudinal guide surface and a second longitudinal sliding surface facing the second longitudinal guide surface;

a fluid supply device;

a pressure adjusting device capable of adjusting a fluid pressure of the fluid supplied from the fluid supply device to a desired predetermined fluid pressure;

a static pressure support portion that is provided on the first longitudinal guide surface or the first longitudinal sliding surface, is supplied with a fluid by the fluid supply device, is acted on by a fluid pressure corresponding to a size of a first gap between the first longitudinal guide surface and the first longitudinal sliding surface, and forms a support rigidity corresponding to the size of the first gap with respect to the movable body; and

and an urging force generating portion that is provided on the second vertical guide surface or the second vertical sliding surface and that urges the movable body in the direction of the first vertical guide surface by being supplied with the fluid whose pressure is adjusted to the predetermined fluid pressure by the pressure adjusting device.

The pressure adjusting device adjusts the magnitude of the predetermined fluid pressure so that the magnitude of the first gap reaches a set value.

With this configuration, the combined state of the first gap and the fluid pressure, which improves the support rigidity, can be easily obtained in the hydrostatic support portion. Therefore, a predetermined fluid pressure that is balanced with the fluid pressure that increases the support rigidity in the hydrostatic support portion is adjusted by the adjustment device and supplied to the acting force generation portion. Thus, the first clearance (set value) for improving the support rigidity is easily obtained in the static pressure support portion, and the static pressure support portion can form a desired support rigidity with respect to the movable body. In this case, since it is not necessary to set the dimensional accuracy between the guide surfaces of the fixed body and the movable body and between the sliding surfaces to high accuracy in order to strictly control the size of the first gap, the number of processing steps is reduced, and the cost is reduced.

A machine tool according to another aspect of the present invention is a machine tool having a tool for machining a workpiece, and includes the hydrostatic sliding guide device according to the above aspect. One of the work piece and the tool is provided to the movable body, and the other of the work piece and the tool is provided to the fixed body. Thus, a low-cost machine tool including a low-cost static pressure slide guide device capable of easily securing the support rigidity of the movable body with respect to the fixed body can be obtained as described above.

Drawings

The foregoing and following features and advantages of the invention will become further apparent from the following description of exemplary embodiments, read in conjunction with the accompanying drawings in which like reference numerals are used to designate like parts.

Fig. 1 is a plan view illustrating an embodiment of a grinding machine including a static pressure slide guide device according to the present invention.

Fig. 2 is a sectional view II-II of fig. 1.

Fig. 3 is a sectional view illustrating the construction of the adjustable throttle valve.

FIG. 4 is a graph illustrating a relationship between flow rate of the adjustable throttle and first fluid pressure.

Fig. 5 is a graph showing a relationship between the first clearance of the static pressure slide guide device and the first fluid pressure in the case where the supply path is provided with the adjustable throttle valve.

Fig. 6 is a graph showing a relationship between the first fluid pressure of the hydrostatic sliding guide apparatus and the support rigidity in the case where the supply path is provided with the adjustable throttle.

Fig. 7 is a graph showing a relationship between the first clearance of the static pressure slide guide device and the support rigidity in the case where the supply path is provided with the adjustable throttle valve.

Fig. 8 is a diagram illustrating modification 1.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Fig. 1 shows an embodiment of a grinding machine 1 using a static pressure slide guide device 40 (see fig. 2) of the present invention. The grinding machine 1 is a wheel-side traversing type grinding machine. Fig. 1 shows an example of a top view of a grinding machine 1, and fig. 2 shows a sectional view II-II in fig. 1. In all the drawings in which the X, Y and Z axes are described, the X, Y and Z axes are orthogonal to each other. The Y-axis represents the vertical upward direction, and the Z-axis and the X-axis represent the horizontal direction. The Z-axis represents the direction of the workpiece rotation axis, and the X-axis represents the direction in which the grinding wheel 15 cuts into the workpiece W.

As shown in fig. 1, a grinding machine 1 includes: a base 11 fixed on the ground; and a head stock 12 and a center device 13, the head stock 12 and the center device 13 being fixed to the base 11, and supporting the workpiece W at both ends thereof so that the workpiece W can rotate. The grinding machine 1 further includes: a wheel head 14 that is movable on the base 11 in the Z-axis direction and the X-axis direction; a grinding wheel 15 rotatably supported by the grinding wheel base 14; a static pressure slide guide 40 (see fig. 2); and a control device 18 that drives the headstock 12 and the grinding wheel 15 and controls the position of the grinding wheel 15 relative to the workpiece W.

The grinding machine 1 grinds a workpiece W rotating about a workpiece rotation axis WZ with a grinding wheel 15. The grinding wheel 15 is formed in a substantially circular disk shape. The grinding wheel 15 rotates about a grinding wheel rotation axis TZ and is configured to be movable relative to the workpiece W in the Z-axis direction and the X-axis direction. Further, the work rotation axis WZ and the grinding wheel rotation axis TZ are both parallel to the Z axis.

As shown in fig. 1 and 2, the head stock 12 includes a base 12a, a spindle housing 12b, and a spindle 12 c. The base 12a is placed on the base 11. The spindle housing 12b is configured to be capable of reciprocating in the Z-axis direction with respect to the base 12 a. The spindle 12c is supported in the spindle housing 12b to be rotatable about a workpiece rotation axis WZ. Further, a Center member 12d is provided at one end of the main shaft 12 c. The main spindle 12c is provided with a drive motor, not shown, and the controller 18 can rotate the main spindle 12c to an arbitrary angle at an arbitrary angular velocity around a workpiece rotation axis WZ passing through the distal end of the tip member 12 d.

The center device 13 includes a base 13a, a center housing 13b, a center housing 13c, and a center member 13 d. The base 13a is placed on the base 11. The tip housing 13b is configured to be movable in the Z-axis direction with respect to the base 13 a. The tip bush 13c is supported in the tip bush housing 13b so as to be rotatable or non-rotatable about the workpiece rotation axis WZ, and the tip bush 13c is provided on the same axis as the spindle 12 c. The workpiece W is supported at both ends or near both ends by a headstock 12 provided with a center head member 12d and a center device 13 provided with a center head member 13 d. A chuck may also be used in place of the tip member.

Further, a traverse base 19 is placed on the base 11. The traverse base 19 is controlled to be positioned at an arbitrary position in the Z-axis direction along the V-shaped guide 23 in accordance with the rotation angle of the ball screw 22 controlled by the Z-axis drive motor 21. The control device 18 outputs a control signal to the Z-axis drive motor 21 while detecting a signal from position detection means such as an encoder, not shown, and performs positioning of the traverse base 19 in the Z-axis direction.

A grinding wheel holder 14 for advancing and retreating the grinding wheel 15 is mounted on the traverse base 19. The wheel head 14 is positioned at an arbitrary position in the X-axis direction along guides 16 and 17 provided integrally with the upper surface of the traverse base 19, in accordance with the rotation angle of the ball screw 30 controlled by the X-axis drive motor 25. The control device 18 outputs a control signal to the X-axis drive motor 25 while detecting a signal from the position detecting means, and positions the position of the wheel slide 14 in the X-axis direction.

In addition, for example, the grinding wheel rotation axis TZ and the workpiece rotation axis WZ are set to be on the same horizontal plane. In this state, the grinding wheel 15 is relatively moved closer to the workpiece W, and a point on the grinding wheel 15 side at a position where the workpiece W and the grinding wheel 15 are in contact is set as a machining point. In this case, although a coolant nozzle for supplying a coolant to the vicinity of the machining point is provided in the grinding machine 1, illustration thereof is omitted. In the grinding machine 1 shown in the example of fig. 1 and 2, a dressing unit for dressing the grinding wheel 15 is attached to the spindle housing 12b, but illustration thereof is omitted.

As shown in fig. 1 and 2, the wheel head 14 includes a slide table 26, a grinding wheel 15, a wheel bearing 27, a wheel drive motor 28, an X-axis drive motor 25, and the like. The rotational driving force of the grindstone driving motor 28 is transmitted to the grindstone 15 via the driving pulley 29, the belt 31, and the driven pulley 32. In the present embodiment, an example of a structure in which the grinding wheel head 14 is advanced and retreated by the X-axis drive motor 25 and the ball screw 30 is shown, but a linear motor may be used, for example. The driving device for advancing and retracting the wheel slide 14 is not particularly limited. Further, the grinding wheel 15 may be directly driven by the drive motor without the belt 31.

As shown in fig. 2, the static pressure slide guide device 40 includes: the traverse base 19 (corresponding to a fixed body), the wheel head 14 (corresponding to a movable body), the hydraulic pump 33 (corresponding to a fluid supply device), the pressure adjusting device 38, the plurality of adjustable throttle valves 24, the static pressure pocket 34 (corresponding to a static pressure support portion) and the static pressure pocket 36 connected to the hydraulic pump 33 via the respective adjustable throttle valves 24, the load pocket 35 (corresponding to an acting force generating portion) connected to the hydraulic pump 33 via the pressure adjusting device 38, and the pressure gauge 39. The traverse base 19 and the grinding wheel base 14 are shared with the grinding machine 1. Further, the

hydrostatic pockets

34, 36 constitute fluid bearings, and the fluid bearings are made relatively rigid in support due to the variable throttle resistance characteristic of the adjustable throttle valve 24.

The hydraulic pump 33 sucks fluid such as oil from the tank 37 and discharges the fluid from the discharge port 33a at a supply pressure Ps. The hydraulic pump 33 is controlled by the control device 18 so as to be able to discharge fluid from the discharge port 33a at a constant supply pressure Ps at all times. Fluid recovery means, not shown, is provided to circulate the discharged fluid through the static pressure slide guide device 40 and finally recover the fluid to the tank 37.

As shown in fig. 1 and 2, the traverse base 19 integrally includes a pair of

guides

16 and 17 on the upper surface thereof for moving the wheel slide 14 in the X-axis direction. That is, the pair of

guides

16 and 17 is a part of the traverse base 19. The pair of

guides

16 and 17 are provided in parallel with each other in the Z-axis direction at a distance, and extend in the X-axis direction by the same distance.

As shown in fig. 2, the guide 16 has a first vertical guide surface 16a serving as a reference surface. The first longitudinal guide surface 16a is formed on a plane orthogonal to the Z axis. The guide 17 has a second vertical guide surface 17a, and the second vertical guide surface 17a is parallel to the first vertical guide surface 16a, and the normal direction of the second vertical guide surface 17a is opposite to the normal direction of the first vertical guide surface 16 a. That is, in the present embodiment, the first vertical guide surface 16a and the second vertical guide surface 17a are disposed to face each other.

A first horizontal guide surface 16b is formed on an orthogonal plane of the first vertical guide surface 16a, which is an upper surface of the guide member 16. A second horizontal guide surface 17b is formed on an upper surface of the guide member 17, i.e., on an orthogonal plane to the second vertical guide surface 17 a. The first horizontal guide surface 16b and the second horizontal guide surface 17b correspond to a pair of horizontal guide surfaces of the present invention. In the present embodiment, the pair of first horizontal guide surfaces 16b and the second horizontal guide surfaces 17b are formed at the same height. However, it is not limited to this, and the first horizontal guide surface 16b and the second horizontal guide surface 17b may be formed at different heights.

As shown in fig. 2, the first horizontal guide surface 16b and the second horizontal guide surface 17b are located outside the first vertical guide surface 16a and the second vertical guide surface 17a, respectively. That is, the first horizontal guide surface 16b is disposed farther from the second vertical guide surface 17a than the first vertical guide surface 16a in the Z-axis direction as viewed from the second vertical guide surface 17 a. Further, the second horizontal guide surface 17b is disposed farther from the first vertical guide surface 16a than the second vertical guide surface 17a in the Z-axis direction as viewed from the first vertical guide surface 16 a.

A pair of first longitudinal sliding surface 14a1 and second longitudinal sliding surface 14a2 are provided on the lower surface side of the slide table 26 provided in the wheel head 14. When the wheel head 14 is placed on the traverse base 19, the paired first vertical sliding surface 14a1 and second vertical sliding surface 14a2 are opposed to the paired first vertical guide surface 16a and second vertical guide surface 17a of the pair of

guides

16 and 17 provided in the traverse base 19, respectively. Hereinafter, the gap formed between the first vertical guide surface 16a and the first vertical sliding surface 14a1 at this time will be referred to as a first gap L1. Hereinafter, the gap formed between the second vertical guide surface 17a and the second vertical sliding surface 14a2 will be referred to as a second gap L2.

Further, a pair of a first horizontal sliding surface 14b1 and a second horizontal sliding surface 14b2 (corresponding to horizontal sliding surfaces) is provided on the lower surface of the slide table 26. The pair of first horizontal sliding surface 14b1 and second horizontal sliding surface 14b2 are disposed to face the pair of first horizontal guide surface 16b and second horizontal guide surface 17b provided in the

guides

16 and 17. The first horizontal sliding surface 14b1 and the second horizontal sliding surface 14b2 are provided with respective recessed static pocket grooves 36.

The static pressure pockets 36 are connected to the hydraulic pump 33 via the adjustable throttle 24. In the present embodiment, each of the adjustable throttle valves 24 is a diaphragm type adjustable throttle valve shown as an example in fig. 3. Further, the adjustable throttle connected to the static pressure pocket 36 is not limited thereto, and may be a slide valve type adjustable throttle, or may be an adjustable throttle of another type. Alternatively, instead of an adjustable throttle, a fixed throttle may be used. Further, the hydraulic pump 33 may be directly connected without a throttle.

As shown in fig. 3, each variable throttle valve 24 includes an upper casing 41, a lower casing 42, and a partition plate 43. Each variable throttle valve 24 causes the fluid of the supply pressure Ps supplied from the inlet port 24a to flow out from the outlet port 24b to each static pressure pocket 36 through a gap R (an annular portion in the upper portion of the outlet port 24b of the lower housing 42) in an annular portion between the lower housing 42 and the partition plate 43, which is a flow path restrictor. The fluid is directly supplied from the hydraulic pump 33 to the inlet port 24 a. The inlet 24a also communicates with the space above the partition plate 43. The cross-sectional area, length, and the like of the passage in the section from the inlet port 24a to the inlet of the space below the partition plate 43, which functions as a fixed throttle, are adjusted (flow rate adjustment of the fixed throttle). Thereby, a pressure difference between the upper side and the lower side of the partition plate 43 is generated.

When fluid is supplied from the hydraulic pump 33 to the static pressure pockets 36 via the variable throttle 24, the fluid pressures P1 in the static pressure pockets 36 act on the static pressure pockets 36 and the first and second horizontal guide surfaces 16b and 17 b. Thereby, each fluid pressure P1 separates and floats the first horizontal sliding surface 14b1 and the second horizontal sliding surface 14b2 of the wheel head 14 from the first horizontal guide surface 16b and the second horizontal guide surface 17 b.

At this time, the fluid is discharged from the static pressure pocket grooves 36 to the space between the first horizontal sliding surface 14b1 and the second horizontal sliding surface 14b2 and the first horizontal guide surface 16b and the second horizontal guide surface 17b at the same time as the separation, and a fluid outflow layer having a predetermined thickness, that is, a gap is formed. By these, the first horizontal guide surface 16b and the second horizontal guide surface 17b are not in contact with the first horizontal sliding surface 14b1 and the second horizontal sliding surface 14b2 in the vertical direction (the direction of gravitational force) via the fluid. Further, detailed operational characteristics and the like of the adjustable throttle 24 will be described later.

As shown in fig. 2, the static pressure pocket groove 34 is formed in a concave shape, provided on the first vertical sliding surface 14a1 facing the first vertical guide surface 16a serving as a reference surface. The static pressure pocket groove 34 is connected to the hydraulic pump 33 via the adjustable throttle 24, similarly to the static pressure pocket groove 36 described above.

For convenience of explanation, first, the aforementioned adjustable throttle valve 24 will be described in detail. In the present embodiment, the adjustable choke valve 24 connected to the static pressure pocket 34 is the same adjustable choke valve (diaphragm type) as the adjustable choke valve 24 connected to the static pressure pocket 36 shown in fig. 3. Further, the adjustable throttle may be a slide valve type adjustable throttle, or may be an adjustable throttle of another type. Alternatively, instead of an adjustable throttle, a fixed throttle may be used. Corresponding effects can also be achieved thereby.

As described above, the variable throttle valve 24 causes the fluid supplied from the inlet port 24a to flow out from the outlet port 24b to the static pressure pocket 34 through the gap R (the annular portion of the upper portion of the outlet port 24b of the lower housing 42) in the annular portion between the lower housing 42 and the partition plate 43, which serves as the throttle of the flow path shown in fig. 3. At this time, if the first gap L1 (see fig. 2), which is a gap between the first vertical guide surface 16a and the first vertical sliding surface 14a1, becomes small, the fluid in the static pocket groove 34 cannot flow out well through the first gap L1, and the pressure in the static pocket groove 34 (the first fluid pressure P1) increases.

Therefore, the pressure of the fluid filled in the outlet port 24b and the fluid filling chamber 24c communicating with the static pressure pocket 34 is also increased. The increased pressure of the fluid pushes up the diaphragm 43, increasing the gap R of the annular portion, and increasing the flow rate of the fluid through the gap R of the annular portion (see the graph of fig. 4). However, as shown in the graph of fig. 4, if the pressure of the fluid in the static pressure pocket 34 excessively increases, the pressure difference between the upper side and the lower side of the diaphragm 43 decreases, and the flow rate decreases rapidly.

For example, when the wheel slide 14 moves from the above state in the direction of the second vertical guide surface 17a in the Z-axis direction, the first clearance L1 increases. Accordingly, the amount of fluid flowing out of the first clearance L1 increases, and the pressure of the fluid in the static pressure pocket 34 decreases.

Fluid is supplied from the hydraulic pump 33 to the static pressure pocket 34 via the adjustable throttle 24 having such flow rate characteristics. At this time, the first fluid pressure P1 in the static pocket 34 fluctuates due to the load supported by the fluid bearing, and becomes the relationship between the first gap L1 and the first fluid pressure P1 shown in the graph Gr1 in fig. 5, and the pressure in the static pocket 34 is adjusted based on this relationship. In the graph Gr1 of fig. 5, the abscissa axis represents the first gap L1(μm), and the ordinate axis represents the first fluid pressure P1 (MPa). The flow rate of the fluid bearing at this time is a relationship between the first fluid pressure P1 in the static pressure pocket 34 and the flow rate of the fluid bearing as shown in fig. 4.

Next, the relationship between the first fluid pressure P1 and the support rigidity G will be described. A graph Gr2 of fig. 6 shows a relationship between the first fluid pressure P1 and the support rigidity G in the case where the adjustable throttle 24 is provided on the supply path for supplying the fluid to the static pressure pocket 34. In fig. 6, for reference, a characteristic (graph Gr3) in the case where a fixed throttle is disposed between the hydraulic pump 33 and the static pressure pocket 34 instead of the adjustable throttle 24 is described.

As can be seen from fig. 6, graph Gr2 allows a greater support stiffness G to be obtained with respect to graph Gr 3. Thus, in the present embodiment, the adjustable throttle 24 is employed. As can be seen from fig. 6, in the adjustable throttle 24, a large support rigidity G cannot be obtained in the region I where the first fluid pressure P1 is small and in the region III where the first fluid pressure P1 is large. Therefore, in the present embodiment, the support rigidities G1 to G2 obtained in the intermediate region II of the first fluid pressure P1 are set to the desired support rigidity G, as an example.

That is, as shown in fig. 6, in order to obtain the desired support rigidity G (G1 to G2), the first fluid pressure P1 in the static pocket 34 is set to fluid pressures P1a to P1b corresponding to the desired support rigidity G (G1 to G2). The value set as the pressure adjustment range of the first fluid pressure P1 may not have a width as in the present embodiment, and may be, for example, only a predetermined point (pressure adjustment point) within the fluid pressures P1a to P1 b. In order to realize the fluid pressures P1a to P1b or the pressure control point of the first fluid pressure P1, an adjustment portion, not shown, of the pressure control device 38 is operated. The pressure adjusting device 38 will be described in detail later.

At this time, when the fluid pressures P1a to P1b (the first fluid pressure P1) are applied to the graph Gr1 in fig. 5, the widths of the first gaps L1 (the gaps L1a to L1b) corresponding to the fluid pressures P1a to P1b are very small. That is, it is difficult to adjust the position of the wheel slide 14 with the clearances L1a to L1b as the control values.

In addition, for reference, a relationship between the first clearance L1 and the support rigidity G in the case where the adjustable throttle 24 is used is shown in fig. 7 (graph Gr 4). As can be seen from the graph Gr4, a greater support stiffness can be obtained by using the adjustable throttle 24. However, the range of the first gap L1 corresponding to the desired support rigidity G1 to G2 is also known to be very small.

However, in the present embodiment, the gap L1a to L1b (corresponding to the set values) is realized by adjusting the first fluid pressure P1 to the fluid pressures P1a to P1b in a wide range as described above, which is easy to implement. As described above, the fluid pressures P1a to P1b are obtained by operating and adjusting an adjusting portion (not shown) of the pressure adjusting device 38, which will be described later.

In addition, by setting the first fluid pressure P1 serving as the pressure in the static pocket 34 to P1a to P1b and the like, the wheel head 14 is urged in the direction of the second longitudinal guide surface 17a by the first urging force F1 (see fig. 2). The first acting force F1 is a force generated when the first fluid pressure P1 in the static pocket groove 34 acts on the static pocket groove 34 and the first vertical guide surface 16a facing the static pocket groove 34. When the area of the static pocket 34 receiving the first fluid pressure P1 is S1 (not shown), the first urging force F1 is F1 — P1 × S1.

In the above description, the adjustable throttle 24 is set to be disposed on the supply path between the hydraulic pump 33 and the static pressure pocket 34, and the description is given. However, the method is not limited to this. As already explained above, instead of the adjustable throttle 24, a fixed throttle may be used in the feed path between the hydraulic pump 33 and the static pocket 34. In this case, as shown in the graph Gr3 of fig. 6, the first fluid pressure P1 may be adjusted by the pressure adjusting device 38 so as to fall within a range of, for example, the fluid pressures P1d to P1e, with a predetermined width in the front and rear directions around the fluid pressure P1c corresponding to the point G3 of the first fluid pressure P1 at which the support rigidity G is the maximum. Thus, as in the present embodiment, the region of the maximum support rigidity G (support rigidities G3 to G4) can be easily realized by the fluid pressures P1d to P1e, which are the range of the first fluid pressure P1 having a large amplitude.

Next, the load pocket 35 will be explained. As shown in fig. 2, the load pocket groove 35 (acting force generating portion) is provided on the second vertical sliding surface 14a2 facing the second vertical guide surface 17a, and is formed in a concave shape. As described above, the load pocket 35 is connected to the hydraulic pump 33 via the pressure adjusting device 38. The pressure regulator 38 is a so-called pressure regulator capable of regulating the fluid pressure (second fluid pressure P2 (not shown)) supplied to the load pocket 35 to a desired predetermined fluid pressure P2a (not shown). The pressure adjustment operation may be performed while confirming the value of the pressure gauge 39 shown in fig. 2.

In this case, in the present embodiment, as described above, the predetermined fluid pressure P2a of the load pocket 35 is a fluid pressure in which the first fluid pressure P1, which is the pressure in the static pocket 34, is set to the fluid pressures P1a to P1 b. In other words, the "predetermined fluid pressure P2 a" is a fluid pressure at which the size of the first gap L1 between the first vertical guide surface 16a and the first vertical sliding surface 14a1 is set to a set value (the gaps L1a to L1 b).

Further, the pressure regulating device 38 may be any type of pressure regulator. The pressure adjusting device 38 may be any pressure adjusting device as long as it can adjust the fluid of the supply pressure Ps supplied from the hydraulic pump 33 to the primary side (suction side) of the pressure adjusting device 38 to a desired predetermined fluid pressure P2a (not shown) and can supply the fluid after pressure adjustment to the secondary side (load pocket 35 side).

The predetermined fluid pressure P2a is set to a fluid pressure on the secondary side obtained when a predetermined flow rate of fluid is set in advance from the primary side to the secondary side of the pressure regulator 38. At this time, the predetermined flow rate set in advance is a flow rate corresponding to the second gap L2 when the first gap L1 on the reference surface side becomes the gaps L1a to L1b (set values) set in advance.

At this time, the second fluid pressure P2 (predetermined fluid pressure P2a) is supplied to the load pocket 35, and the wheel head 14 (movable body) is biased in the direction of the first vertical guide surface 16a by the second biasing force F2. The second biasing force F2 is a force generated when the second fluid pressure P2 (predetermined fluid pressure P2a) supplied to the load pocket 35 acts on the load pocket 35 and the second vertical guide surface 17a facing the load pocket 35.

When the area of the load pocket 35 set to the second fluid pressure P2(P2a) is S2 (not shown), the second urging force F2 is F2 — P2(P2a) × S2. The areas S1 and S2 of the static pocket 34 are preferably the same area (S1 — S2), but may be S1 > S2 or S1 < S2 as long as F1 — F2 is achieved.

Thus, the fluid of the supply pressure Ps discharged from the hydraulic pump 33 is regulated to a predetermined fluid pressure P2a (second fluid pressure P2) by the regulator 38, and is supplied to the load pocket 35. That is, the pressure adjusting device 38 adjusts the magnitude of the second fluid pressure P2 to "predetermined fluid pressure P2 a" such that the magnitude of the first gap L1 on the reference surface side is, for example, the gaps L1a to L1b (set values), and the first biasing force F1 and the second biasing force F2 are balanced with each other in the horizontal direction and in the Z-axis direction. The "prescribed fluid pressure P2 a" is set based on the relationship between the magnitude of the first clearance L1 and the first fluid pressure P1 (see fig. 5) corresponding to the magnitude of the first clearance L1.

Next, the operation will be described. In the description, the set value of the first gap L1 on the reference surface side is set to, for example, gaps L1a to L1 b. Further, the adjustment portion, not shown, of the pressure adjusting device 38 is operated in advance, and adjustment is performed to some extent such that the first acting force F1 and the second acting force F2 are balanced with each other in the horizontal direction in a state where the first fluid pressure P1 in the static pressure pocket 34 on the reference surface side reaches the fluid pressures P1a to P1b and the first gap L1 reaches the set values (gaps L1a to L1 b).

As a premise for assembling the grinding machine 1, when the wheel head 14 (movable body) is placed on the traverse base 19 (fixed body), the first clearance L1 on the reference surface side is a clearance L1c (see point P in the graph of fig. 5) larger than the clearances L1a to L1b, which are set values. In this case, the second gap L2 is set to a gap L2c (not shown). In addition, the "first gap L1" + "second gap L2" is always a fixed value. Thus, the gap L2c is always determined based on the size of the gap L1 c. Therefore, the gap L2c is smaller than the gaps L2a to L2b of the second gap L2 when the first gap L1 is set to the gaps L1a to L1b (set values).

In this state, when the grinding machine 1 is started and the hydraulic pump 33 is started, the fluid is discharged at the supply pressure Ps. The discharged fluid is supplied to the static pressure pocket 34 and the load pocket 35. The fluid is supplied to the static pressure pocket 34 on the reference surface side via the variable throttle 24. Further, under the action of the adjustable throttle valve 24, the pressure inside the static pressure pocket 34 (first fluid pressure P1) reaches a fluid pressure P1c (see point P in fig. 5) corresponding to the size of the clearance L1c (> clearances (L1a to L1 b)). Thereby, the fluid pressure P1c urges the wheel head 14 in the direction of the second longitudinal guide surface 17a with the first urging force F1c (P1 c × S1) (see fig. 2). At this time, S1 is the area of the static pressure pocket 34. The first acting force F1c is smaller than the first acting force F1 which is the acting force when the first gap L1 is a set value (gaps L1a to L1 b).

At this time, the gap L2c is smaller than the gaps L2a to L2b of the second gap L2 when the first gap L1 reaches the set value (gaps L1a to L1b) (L2c < (L2a to L2 b)). Accordingly, at this time, the flow rate of the fluid regulated by the pressure regulator 38 and supplied to the load pocket 35 is smaller than a predetermined flow rate set in advance.

Therefore, the fluid pressure P2c regulated by the pressure regulator 38 is higher than the predetermined fluid pressure P2a (P2c > P2 a). Therefore, the second urging force F2c (P2c × S2) is a value larger than the first urging force F1a, and the wheel head 14 (movable body) is urged in the direction of the first vertical guide surface 16a (reference surface) with a force of the magnitude of the urging force (F2c-F1c) to move.

Thereby, as shown by an arrow Ar1 in fig. 5, the gap L1c (point P) of the first gap L1 gradually decreases. Then, the fluid pressure P1c in the static pressure pocket 34 connected to the adjustable throttle 24 gradually rises, eventually falls within the range of the fluid pressures P1a to P1b, and the first clearance L1 reaches a set value (clearances L1a to L1 b).

At this time, in the second gap L2, the gap L2c is expanded as the gap L1c of the first gap L1 is reduced. The second fluid pressure P2 gradually decreases, and when the pressure in the static pressure pocket 34 on the reference surface side reaches the fluid pressures P1a to P1b (set values), the second fluid pressure P2 becomes the predetermined fluid pressure P2 a. However, in this case, it is considered that the fluid pressures P1a to P1b (set values) do not correspond to the predetermined fluid pressure P2 a. In this case, a pressure adjusting unit (not shown) of the pressure adjusting device 38 is operated to match the fluid pressures P1a to P1b (set values) with the predetermined fluid pressure P2 a.

As a result, as described above, the first biasing force F1 biased by the fluid pressures P1a to P1b (set values) and the second biasing force F2 biased by the predetermined fluid pressure P2a (P2c × S2) are balanced with each other in the horizontal direction (Z-axis direction), and particularly, a large support rigidity G is obtained on the reference surface side (G1 to G2).

By starting the grinding machine 1 in this way, the traverse base 19 and the wheel base 14 roughly assembled can be adjusted to a desired assembled state, and the support rigidity G of the guide on the reference surface side can be set to a predetermined level.

In the above-described embodiment, the pressure regulating value of the pressure regulating device 38 is set to a state in which it is set in advance to some extent when the grinding machine 1 is started, and the description has been given. But is not limited to this manner. When the grinding machine 1 is started, the pressure regulating value of the pressure regulating device 38 may not be regulated at all. In this case, the static pressure slide guide 40 may be activated to supply the fluid to the static pressure pocket 34 and the load pocket 35, and then the pressure regulation of the pressure regulator 38 may be started. The pressure adjustment takes a little time, but it is expected that the same effects as those of the above embodiment, such as improvement in the processing accuracy and reduction in the number of assembly steps, can be achieved.

In the above embodiment, each of the static pockets 36 is provided on the pair of first horizontal sliding surface 14b1 and second horizontal sliding surface 14b2 (horizontal sliding surfaces) of the wheel head 14. However, the static pocket grooves 36 may be eliminated, and a sliding type guide system may be adopted in which the first horizontal sliding surface 14b1 and the second horizontal sliding surface 14b2 slide in contact with the first horizontal guide surface 16b and the second horizontal guide surface 17b (horizontal guide surfaces). This also achieves the same effects as those in the above embodiment.

In the above embodiment, the static pressure pocket groove 34 is provided in the first longitudinal sliding surface 14a1, and the load pocket groove 35 is provided in the second longitudinal sliding surface 14a 2. However, the method is not limited to this. The static pressure pocket groove 34 may be provided on the first vertical guide surface 16a facing the first vertical sliding surface 14a1, and the load pocket groove 35 may be provided on the second vertical guide surface 17a facing the second vertical sliding surface 14a 2. The same effects as those of the above embodiment can be obtained.

As shown in fig. 8, as modification 1 of the above embodiment, guides 16 and 17 may be supported from below by static pressure pockets 46 and 47. This also achieves the same effects as those in the above embodiment.

With the above-described embodiment, in the static pocket 34, a combined state between the first clearance L1 for improving the support rigidity G and the fluid pressure of the fluid (first fluid pressure P1) supplied to the static pocket 34 can be easily obtained. Therefore, the pressure adjusting device 38 adjusts the predetermined fluid pressure P2a, which is balanced with the fluid pressures (the first fluid pressures P1a to P1b) that increase the support rigidity G in the static pressure pocket 34, and supplies the adjusted fluid pressure to the load pocket 35 (the acting force generating portion). Thus, the first clearance L1 (clearances L1a to L1b) for increasing the support rigidity G is easily obtained in the static pocket 34, and the static pocket 34 has a desired support rigidity G (clearances G1 to G2) with respect to the wheel head 14. In this case, since the size of the first gap L1 (gaps L1a to L1b) is strictly controlled, it is not necessary to set the dimensional accuracy between the traverse base 19 and the guide surfaces 16a and 17a of the wheel seat 14 and between the sliding surfaces 14a1 and 14a2 to high accuracy, and therefore the number of processing steps is reduced, and the cost is reduced. Further, the gap in the vertical direction (Y-axis direction) is adjusted by the balance with the gravity. However, in the left-right direction (Z-axis direction), the gap between the static pressure pocket 34 and the load pocket 35 can be appropriately adjusted without balancing the gravity, and the support rigidity can be maintained high.

In addition, according to the above embodiment, the fluid supplied to the static pressure pocket 34 is supplied through the adjustable choke valve 24, and the adjustable choke valve 24 is provided on the supply path from the hydraulic pump 33 to the static pressure pocket 34, and the fluid pressure is varied in accordance with the size of the first gap L1. In general, the adjustable throttle 24 has a characteristic that a large support rigidity can be obtained with respect to the fixed throttle. Therefore, a large supporting rigidity of the traverse base 19 by the wheel head 14 can be obtained.

In addition, with the above-described embodiment, the set values of the first clearance L1 (clearances L1a to L1b) are set so that the desired support rigidity G (G1 to G2) can be obtained based on the relationship between the size of the first clearance L1 and the fluid pressure P1 corresponding to the size of the first clearance L1 (see fig. 5). This can reliably obtain the desired support rigidity G (G1 to G2).

In the above embodiment, the traverse base 19 has the pair of horizontal guide surfaces 16b and 17b on the respective orthogonal planes of the first vertical guide surface 16a and the second vertical guide surface 17 a. The wheel head 14 has a pair of horizontal sliding surfaces 14b1, 14b2 facing the pair of horizontal guide surfaces 16b, 17b, respectively. This makes it possible to obtain the hydrostatic sliding guide device 40 in which the traverse base 19 is supported by the wheel head 14 with improved rigidity and which moves smoothly in the X-axis direction.

In the above embodiment, the static pressure slide guide device 40 is used for a grinding machine. However, the present invention is not limited to this, and the hydrostatic sliding guide device 40 may be used for a machine tool other than a grinding machine. For example, the present invention can be used in a lathe, a milling machine, a drilling machine, a machining center, and the like, and each of the movable bodies supporting one of a tool and a workpiece of the machine tool is supported by a fixed body supporting the other of the tool and the workpiece via the static pressure slide guide device 40.

Claims

1. A static pressure slide guide device is provided with:

a fluid supply device;

a pressure adjusting device that is a pressure regulator and that can adjust a fluid pressure of the fluid supplied by the fluid supply device to a desired predetermined fluid pressure;

an urging force generating portion provided on the second longitudinal guide surface or the second longitudinal sliding surface and urging the movable body in a direction of the first longitudinal guide surface by being supplied with the fluid whose pressure is adjusted to the predetermined fluid pressure by the pressure adjusting device,

the pressure adjusting device adjusts the pressure of the prescribed fluid so that the size of the first gap reaches a set value,

the fluid supplied to the static pressure support portion is supplied via an adjustable throttle provided in a supply path from the fluid supply device to the static pressure support portion, and the fluid pressure is varied in accordance with the size of the first gap.

2. The hydrostatic sliding guide of claim 1, wherein

The set value of the first gap is set based on a relationship between the size of the first gap and the fluid pressure corresponding to the size of the first gap to obtain the desired support rigidity.

3. The hydrostatic sliding guide device according to claim 1, wherein

The fixed body has a pair of horizontal guide surfaces on respective orthogonal planes of the first longitudinal guide surface and the second longitudinal guide surface,

the movable body has a pair of horizontal sliding surfaces facing the pair of horizontal guide surfaces, respectively.

4. A machine tool having a tool for working a work piece, comprising the static pressure slide guide device according to claim 1 or 2,

one of the work piece and the tool is provided to the movable body,

the other of the work piece and the tool is provided to the fixed body.