JP6790574B2 - Spindle device and grinder equipped with the spindle device - Google Patents

Description

The present invention relates to a spindle device. In particular, the present invention relates to a compensating force pressurizing unit that applies a compensating force to a bearing force of a static pressure bearing that receives a radial load provided in a spindle device of a grinder using a grindstone.

A grinder using a grindstone includes a grindstone shaft on which a rotary grindstone is attached as a rotary shaft body, and the rotary shaft body is rotatably supported by a shaft support called a journal. A rotary grindstone is attached to one end of the rotating shaft body, and a pulley portion is attached to the other end. The rotational force generated by a rotational power source such as a motor is transmitted to the pulley portion via a rotational transmission device such as a belt to rotate the rotary shaft body and rotate the rotary grindstone.

When the pulley portion is rotationally transmitted by the belt, a radial load is generated on the rotating shaft body integrated with the pulley portion. This radial load is supported by a hydrostatic bearing provided on the shaft support.

A static pressure bearing that receives a radial load receives a radial load acting on a rotating shaft body by forming a plurality of pressure oil pockets in the circumferential direction on the radial surface (axial surface) of the shaft support. For example, four pressure oil pockets are arranged at equal intervals, and when pressure oil is supplied from the oil supply source to each pocket via the supply path, it is suitable for support by a pressure adjusting throttle provided in the supply path. It is supplied after adjusting the pressure to the oil pressure.

Specifically, the static pressure bearing that receives the radial load is provided with a pressure oil pocket and a land portion on the inner peripheral surface of the shaft support having a constant bearing gap with the rotating shaft body. Then, the rotating shaft body is supported by the hydraulic pressure (static pressure) of the bearing oil supplied to the bearing gap between the pressure oil pocket and the rotating shaft body and the hydraulic pressure generated between the land portion and the rotating shaft body. To.

However, in the static pressure bearing described above, when the transmission force of the rotation transmission device that transmits rotation to the rotation shaft body is large, a large radial load is applied to the pulley portion by the belt, and the radial load is applied to the rotation shaft body. Is done. Pushed by the pulley load, the position of the rotating shaft becomes closer to the static pressure bearing. If an excessive processing force in the radial direction is applied from the grindstone in this state, the rotating shaft body and the hydrostatic bearing may come into contact with each other and be damaged.

For this reason, conventionally, the static pressure bearing as described above is provided with a means for applying a correction force in a direction that opposes the radial load acting on the rotating shaft body. That is, there is a means for applying a correction force that cancels the radial load. For example, by changing the area of a plurality of pressure oil pockets constituting the hydrostatic bearing, a correction force against a radial load is generated so that the proper bearing function of the hydrostatic bearing can be exhibited (patented). Reference 1).

Special Publication No. 59-17286 Japanese Unexamined Patent Publication No. 2001-304260

However, the conventional means for generating a correction force affects the performance of the original hydrostatic bearing by providing the means. Therefore, when it becomes necessary to change the magnitude of the compensating force, it is necessary to change the configuration of the hydrostatic bearing itself, and the change in the configuration is the magnitude of the bearing performance and compensating force of the hydrostatic bearing. It is necessary to consider the two in relation to each other, which has the disadvantage of complicating the design.

Therefore, the present invention was devised in view of the above points, and the problem to be solved by the present invention is to determine the magnitude of the correction force without affecting the bearing performance of the hydrostatic bearing. It is to be changeable.

In order to solve the above problems, the present invention takes the following means.

The spindle device according to the present invention has, as a basic configuration, a rotating shaft body, a shaft support that rotatably supports the rotating shaft body, a power source that generates a rotational force of the rotating shaft body, and the power source. It is provided with a rotation transmission device for transmitting the rotational force of the above to the pulley portion provided on the rotation shaft body via a belt. The shaft support is provided with a radial static pressure bearing that supports a load in the radial direction of the rotating shaft body and a correction force pressurizing portion that corrects the bearing force of the radial static pressure bearing. The bearing and the compensating force pressurizing portion are provided at different positions in the axial direction of the rotating shaft body, and the radial static pressure bearing has a plurality of pressure oil pockets in the circumferential direction and the pressure oil pockets. Bearing oil is supplied from the pressure oil supply source via a supply path having a throttle portion, the correction force pressurizing portion has one pressure oil pocket in the circumferential direction, and the pressure oil pocket is filled with oil. Bearing oil is supplied from the supply source via the supply path, and the pocket shape of the pressure oil pocket of the compensating force pressurizing portion is a correction in the direction of reducing the radial force acting on the rotating shaft from the pulley portion. It is formed as a pocket shape that generates force.

According to the present invention, the radial static pressure bearing that supports the load in the radial direction of the rotating shaft body and the correction force pressurizing portion that corrects the bearing force of the radial static pressure bearing are provided at different positions in the axial direction. Be done. As a result, the magnitude of the correction force can be set by the correction force pressurizing portion without affecting the bearing performance of the radial static pressure bearing.

Further, according to the present invention, the correction force in the direction of reducing or canceling the force in the radial direction acting on the rotating shaft from the pulley portion by the correction force pressurizing portion is generated by one pressure oil formed in the circumferential direction. This can be achieved with a simple configuration because it is only done by making the axial widths of the pockets different.

The spindle device of the present invention may have the following configuration as a preferable configuration.

First, the correction force pressurizing unit has an axial surface facing the rotating shaft body in the radial direction and a radial surface facing the rotating shaft body in the axial direction. The pressure oil pocket is formed at a corner where the axial surface and the radial surface intersect at a position where the thrust load of the rotating shaft body can also be received, and is formed across both sides of the shaft. The pressure oil pocket on the directional surface is configured to generate a correction force, and the pressure oil pocket on the radial surface is configured to receive a thrust load, and the pressure oil pocket is a supply path having a throttle portion from the oil supply source. The bearing oil can be supplied via the above.

According to the above configuration, one pressure oil pocket is formed across a corner portion where the axial plane (radial plane) and the radial plane (thrust plane) of the shaft support intersect. As a result, the one pressure oil pocket can have both a thrust bearing function for the shaft support and a correction force generating function for the static pressure bearing in the radial direction. Changing the axial width in the pocket as a compensating force pressurizing part changes the depth of the pocket from the viewpoint of the thrust bearing, but the change in the pocket depth affects the bearing capacity of the thrust bearing. do not do. Moreover, the correction force for the static pressure bearing in the radial direction can be changed without affecting the bearing performance of the thrust bearing function. This is because the pressure oil pocket is formed so as to straddle the corners, a correction force is generated by the pressure oil pocket on the axial surface, and a thrust load is received by the pressure oil pocket on the radial surface. As a result, it is possible to change the magnitude of the correction force without changing the bearing performance of the thrust bearing by changing the axial size without changing the size of the radial surface of the pressure oil pocket. ing. According to the above configuration, the axial space is required because the compensating force pressurizing part is formed separately from the radial static pressure bearing, but by using it also as the thrust bearing part, the axial space is made more efficient. Can be used well.

Further, it has an axial surface facing the outer peripheral surface of the rotating shaft body in the radial direction, the pressure oil pocket is formed on the axial direction surface, and the pressure oil pocket of the correction force pressurizing portion is filled with oil. The hydraulic pressure generated by the supply source can be supplied without going through the throttle portion.

According to the above configuration, the oil pressure generated by the oil supply source is supplied to the pressure oil pocket of the compensating force pressurizing unit as it is, that is, without being depressurized, without passing through the throttle portion. Therefore, since the correction force can be generated by using the oil pressure generated by the oil supply source, the oil pressure of the oil supply source can be utilized as effectively as possible.

Further, the compensating force pressurizing portion may be configured to be set between the pulley portion and the radial static pressure bearing.

According to the above configuration, the compensating force pressurizing portion is arranged closer to the pulley portion than the axial position of the radial static pressure bearing. By the way, the rotary shaft body provided with the pulley portion bends and deforms in the axial direction due to the load of the rotational transmission force of the pulley portion. Along with this, the position of the pulley portion changes. However, since the correction force pressurizing portion for generating the correction force is located near the pulley portion, the fluctuation can be suppressed.

Further, the rotating shaft body has a small diameter portion having a diameter smaller than the facing surface between the facing surface with the radial static pressure bearing and the pulley portion, and the compensating force pressurizing portion faces the small diameter portion. It can be configured as set.

According to the above configuration, the correction force pressurizing portion is set at a position facing the small diameter portion of the rotating shaft body, so that it can be configured compactly.

The spindle device having each of the above-described configurations of the present invention can be provided in the grinder. According to such a grinder, the features of the spindle device having each of the above-described configurations can be effectively utilized.

According to the present invention, the magnitude of the correction force can be changed without affecting the bearing performance of the hydrostatic bearing.

It is a perspective view which shows the example of the appearance of the grinder system of this embodiment. It is a perspective view which shows the schematic structure of the grinder of this embodiment. It is a side view which shows the schematic structure of a grinder. It is a top view which shows the schematic structure of a grinder. It is sectional drawing which shows 1st Embodiment of the bearing composition of the grindstone shaft of a grinder. FIG. 5 shows a sectional view taken along line VI-VI of FIG. 5, which is a sectional view of a radial hydrostatic bearing. FIG. 5 is an enlarged cross-sectional view showing a portion of a thrust bearing configuration and a configuration of a compensating force pressurizing portion set on a small diameter shaft portion of the grindstone shaft of the first embodiment of FIG. It is a perspective view which shows by partially missing the shaft support in 1st Embodiment. It is a top view which develops and shows the inner surface shape of the pressure oil pocket of the correction force pressurizing part of 1st Embodiment. It is a figure which showed the acting force by a correction force pressurizing part as an area. It is a figure which shows the modification of the pressure oil pocket shown in FIG. 7. It is sectional drawing which shows the 2nd Embodiment of the bearing composition of the grindstone shaft of a grinder. It is a perspective view which shows the shaft support of 2nd Embodiment. It is a top view which shows the inner surface shape of the pressure oil pocket of 2nd Embodiment developed. It is sectional drawing which shows the state which the load of a radial load is not applied to the grindstone shaft in a radial static pressure load. It is sectional drawing which shows the state which a normal radial load was applied from the state of FIG. It is sectional drawing which shows the state which the radial load is further applied from the state of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present embodiment is a case of a spindle device that supports a grindstone shaft provided in a grinder that grinds an engine cam or the like.

First, the outline of the grinder 2 will be described. FIG. 1 shows an example of the appearance of the grinder system 1. The grinder system 1 houses the grinder 2 shown in FIGS. 2 to 4 inside, and has a cover 1A, a movable door 1B, fine adjustment handles 1C, 1D, a control device 80, and the like.

2 to 4 show the overall configuration of the grinder 2. The grinder 2 has a bed 10, a table 20, a headstock 30, a tailstock 40, a grindstone base 50, and the like. In the figure in which the X-axis, the Y-axis, and the Z-axis are shown, the X-axis, the Y-axis, and the Z-axis are orthogonal to each other, the Y-axis direction indicates vertically upward, and the grindstone 55 works in the Z-axis direction. The horizontal direction of cutting into W is shown, and the X-axis direction shows the horizontal direction parallel to the rotation axis 31J of the main shaft 31.

As is well shown in FIG. 4, the bed 10 is formed in a substantially T shape in a plan view. Then, as is well shown in FIG. 2, X-axis guide surfaces 12 and 12V extending along the X-axis direction are provided, and an X-axis slit 12K extending along the X-axis direction is provided. Further, as is well shown in FIGS. 2 and 4, the bed 10 is provided with Z-axis guide surfaces 15 and 15V extending along the Z-axis direction, and is provided with a Z-axis slit 15K extending along the Z-axis direction. Has been done.

The grindstone stand 50 is placed on the bed 10, is statically pressure-guided supported by the Z-axis guide surfaces 15 and 15 V, and can reciprocate along the Z-axis direction. The grindstone stand drive motor 50M rotates the ball screw 50B (see FIG. 3) based on the control signal from the control device 80. The control device 80 controls the grindstone stand drive motor 50M while detecting the position of the grindstone stand 50 in the Z-axis direction based on the detection signal from the encoder 50E (rotation detection means), and the position of the grindstone stand 50 in the Z-axis direction. To control. As shown in FIG. 3, a nut 50N is screwed into the ball screw 50B, and the nut 50N is connected to the grindstone base 50 via an arm 50A inserted through a Z-axis slit 15K (see FIG. 2). ing. Therefore, when the grindstone base drive motor 50M rotationally drives the ball screw 50B, the position of the nut 50N in the Z-axis direction moves, and the grindstone base 50 connected to the nut 50N via the arm 50A Z along the Z-axis guide surface 15. Move in the axial direction.

The grindstone base 50 is provided with a grindstone shaft 54 and a grindstone motor 55M that are rotatably supported around a grindstone rotation axis 55J parallel to the X-axis direction. As shown in FIG. 4, both the grindstone rotation axis 55J and the spindle rotation axis 31J are parallel to the X axis, and as shown in FIG. 3, the grindstone rotation axis 55J and the spindle rotation axis 31J are on the same virtual plane VM. It is in.

A large-diameter pulley 51 is attached to the grindstone motor 55M (corresponding to the "power source" of the present invention). A grindstone 55 is attached to one end of the grindstone shaft 54, and a small diameter pulley 52 (corresponding to the “pulley portion” of the present invention) is attached to the other end of the grindstone shaft 54. A belt 53 for power transmission is hung on the large-diameter pulley 51 and the small-diameter pulley 52. A rotation detecting means 55S capable of detecting the rotation speed of the grindstone 55 is provided in the vicinity of the grindstone shaft 54. The control device 80 controls the grindstone motor 55M while detecting the rotation speed of the grindstone 55 based on the detection signal from the rotation detection means 55S to control the rotation speed of the grindstone 55.

The grindstone 55 has a circular cross section cut in a plane orthogonal to the grindstone shaft 54, and CBN abrasive grains are hardened on the outer peripheral surface of the grindstone 55 with an adhesive, electrodeposition, etc., and are integrated with the grindstone shaft 54. Rotates around the grindstone rotation axis 55J. Most of the grindstone 55 is covered with the grindstone storage case 91 except for the periphery of the grinding point K (see FIG. 3) for grinding the work W. A coolant nozzle 58 for discharging coolant for cooling and lubrication is provided on the upper portion of the grindstone storage case 91 toward the grinding point K of the grindstone 55. Coolant is supplied to the coolant nozzle 58 from a coolant tank (not shown), and the outer circumference of the grindstone 55 on the side facing the work W and the virtual plane VM including the grinding point K (the grindstone rotation axis 55J and the spindle rotation axis 31J). The coolant used for cooling and lubricating the surface and the intersection) is collected in a flow path (not shown) and returned to the coolant tank. Impurities are removed in the coolant tank by the equipment shown in the figure.

The table 20 is placed on the bed 10, is statically pressure-guided supported by the X-axis guide surface 12, and can reciprocate along the X-axis direction. The table drive motor 20M rotates a ball screw (not shown) based on a control signal from the control device 80. The control device 80 controls the table drive motor 20M while detecting the position of the table 20 in the X-axis direction based on the detection signal from the encoder 20E (rotation detection means) to control the position of the table 20 in the X-axis direction. .. A nut (not shown) is screwed into the ball screw, and the nut is connected to the table 20 via an arm (not shown) inserted through the slit 12K. Therefore, when the table drive motor 20M rotationally drives the ball screw, the position of the nut in the X-axis direction moves, and the table 20 connected to the nut via the arm moves in the X-axis direction along the X-axis guide surface 12. A headstock 30 is fixed to one end of the table 20 in the X-axis direction, and a tailstock 40 is fixed to the other end.

The headstock 30 includes a spindle 31 that rotates around a spindle rotation axis 31J parallel to the X-axis direction, a center 32 whose central axis is the spindle rotation axis 31J, a spindle motor 31M that rotationally drives the spindle 31, an encoder 31E, and the like. have. A drive fitting 33 for connecting the spindle 31 and the work W is attached to the spindle 31. The drive metal fitting 33 has a grip portion 33A for gripping the work W and a connecting portion 33B for connecting the grip portion 33A and the spindle 31, and is integrated with the spindle 31 to rotate around the spindle rotation axis 31J. And rotate the work W. The control device 80 controls the spindle motor 31M while detecting the rotation angle and rotation speed of the spindle 31 based on the detection signal from the encoder 31E (rotation detection means), and controls the rotation angle and rotation speed of the spindle 31 (that is, the work). W's rotation angle and number of rotations) are controlled.

The tailstock 40 has a center 42 whose central axis is the spindle rotation axis 31J, and a ram 41 that accommodates the center 42 and is urged in the direction toward the spindle 30. The central axis of the center 42 of the tailstock 40 and the central axis of the center 32 of the headstock 30 both coincide with the spindle rotation axis 31J. The work W sandwiched between the center 32 and the center 42 is pressed toward the headstock 30 by the center 42, and is rotated around the spindle rotation axis 31J by the rotation of the spindle 31 and the drive fitting 33.

[First Embodiment]
5 and 8 show a first embodiment of the bearing configuration of the grindstone shaft 54, which is a feature of the present embodiment in the grinder 2 described above. First, the outline of the bearing configuration of the grindstone shaft 54 will be described with reference to the cross-sectional view shown in FIG.

The grindstone shaft 54 is supported by a shaft support 60 called a journal. As seen in FIG. 5, a grindstone 55 is provided at the left end (one end) of the grindstone shaft 54. A small diameter pulley 52 is provided at the right end (the other end), and the grindstone shaft 54 is rotated via the belt 53 by driving the grindstone motor 55M to rotate the grindstone 55. The grindstone shaft 54 in the present embodiment corresponds to the rotating shaft body of the present invention, and the small diameter pulley 52 corresponds to the pulley portion of the present invention.

The grindstone shaft 54 includes a large-diameter shaft portion 54A and a small-diameter shaft portion 54B having a diameter smaller than that of the large-diameter shaft portion 54A. On the corresponding shaft support 60 of the large-diameter shaft portion 54A, a static pressure bearing 82 (hereinafter referred to as “radial static pressure bearing”) that receives a load in the radial direction of the grindstone shaft 54 is provided on both left and right ends of the large-diameter shaft portion 54A. It is installed in two places corresponding to the place. In addition. Reference numeral 57 in FIG. 5 is a discharge oil pocket formed between the radial static pressure bearings 82 on both sides, and receives the bearing oil discharged from the radial static pressure bearing 82 and discharges the bearing oil to the oil sump.

A compensating force for the radial load of the static pressure bearing 85 (hereinafter referred to as "thrust static pressure bearing") that receives the load in the thrust direction of the grindstone shaft 54 and the radial static pressure bearing 82 described above is generated in the small diameter shaft portion 54B. The compensating force pressurizing unit 62 is installed integrally. The installation position of the thrust static pressure bearing 85 and the compensating force pressurizing unit 62 is defined as a position between the position of the small diameter pulley 52 which is the source of the radial load and the position where the radial static pressure bearing 82 is installed. ing.

FIG. 6 shows the radial hydrostatic bearing 82 and shows the VI-VI line cross section of FIG. The radial static pressure bearing 82 is formed on the inner peripheral surface of the shaft support 60 by arranging a plurality of four pressure oil pockets 64 in the present embodiment in a concave shape at equal intervals in the circumferential direction. The land portion 65 is formed between the four pressure oil pockets 64. As a result, the grindstone shaft 54 is formed by the hydraulic pressure (static pressure) of the bearing oil supplied to the bearing gap between the pressure oil pocket 64 and the grindstone shaft 54 and the hydraulic pressure generated between the land portion 64 and the grindstone shaft 54. It is supported and receives the radial load of the grindstone shaft 54.

The pressure oil generated in the oil supply source 66 is supplied to the pressure oil pocket 64 of the radial static pressure bearing 82 through the supply path 67. A pressure oil adjusting throttle 68 is provided in the supply path 67, and the pressure oil of the oil supply source 66 is adjusted to reduce pressure and supplied to the pressure oil pocket 64. In this decompression adjustment, the pressure oil to each pressure oil pocket 64 is adjusted in consideration of the acting direction of the radial load so as to support the radial load of the grindstone shaft 54.

FIG. 7 shows an enlarged portion of the small diameter shaft portion 54B of the grindstone shaft 54 of FIG. 6, and shows the configuration of the thrust static pressure bearing 85 and the configuration of the correction force pressurizing portion 62. Both configurations 85 and 62 are provided in the pressure oil pocket 96 formed at the corner of the shaft support 60 of the journal. The passage gap through which the bearing oil flows in FIG. 7 is exaggerated. The same applies to the passage gap of the bearing oil in the other figures.

As shown in FIG. 7, the grindstone shaft 54, which is a rotating shaft body, has a large-diameter shaft portion 54A and a small-diameter shaft portion 54B formed in a stepped concave cross-sectional shape. The shaft support 60 as a journal that supports the grindstone shaft 54 is arranged in a state of being inserted into a concave portion having a concave cross-sectional shape of the grindstone shaft 54. The grindstone shaft 54 is supported so as to be slightly movable in the axial direction and the radial direction. The axial support is configured as the thrust static pressure bearing 85 of the present embodiment, and the correction force pressurizing portion 62 for generating a correction force in the radial direction is configured in the support in the radial direction.

First, the configuration of the thrust static pressure bearing 85 in the pressure oil pocket 96 will be described. As shown in FIG. 7, the thrust support by the shaft support 60 of the grindstone shaft 54 of the present embodiment is performed by static pressure support via bearing oil. Thrust support is performed by the stepped portions x and y on both sides of the stepped shape of the grindstone shaft 54. The step portions x and y are formed by arranging the first forming surface 70 (diameter direction surface) and the second forming surface 75 (axial direction surface) at right angles. The first forming surface 70 (diameter direction surface) is composed of a first forming surface 70A (diameter direction surface) formed on the shaft support side and a first forming surface 70B (diameter direction surface) formed on the grindstone shaft side. There is. Both 70A and 70B are arranged so as to face each other and form a distribution gap. This distribution gap is the first throttle 92. The first forming surface 70 (diameter direction surface) is formed so as to be perpendicular to the grindstone axis, and the drawing state of the first drawing 92 changes due to the axial movement of the grindstone shaft 54.

The second forming surface 75 (axial surface) is composed of a second forming surface 75A (axial surface) formed on the shaft support side and a second forming surface 75B (axial surface) formed on the grindstone shaft side. There is. Both 75A and 75B are arranged so as to face each other and form a distribution gap. Since the grindstone shaft 54 of the present embodiment is a rotating shaft body, the flow gap is formed as a cylindrical gap. This distribution gap is the second throttle 94. The second forming surface 75 (axial surface) on which the second drawing 94 is formed is in the same direction as the grindstone axis. Therefore, the drawing state of the second drawing 94 does not change even if the grindstone shaft 54 moves in the axial direction.

The supply of bearing oil to the flow gap (first throttle 92) of the first forming surface 70 (diameter direction surface) and the flow gap (second drawing 94) of the second forming surface 75 (axial surface) is a shaft support. This is done through a supply path 98 formed in 60 and a pressure oil pocket 96. The bearing oil is supplied to the pressure oil pocket 96 from the same oil supply source 66 as the supply to the pressure oil pocket 64 of the radial static pressure bearing 82 described above via the pressure adjusting throttle 99 of the supply path 98. It is supposed to be done. The pressure oil pocket 96 is formed by cutting off the right-angled forming portion of the first forming surface 70 (diameter direction surface) and the second forming surface 75 (axial direction surface), and is formed in an annular shape. There is. That is, unlike the pressure oil pockets 64 provided in the radial static pressure bearing 82 described above, only one pressure oil pocket 96 of the thrust static pressure bearing 85 is provided on the circumference.

The pressure oil pocket 96 includes a first forming surface opening 71 that opens to the first forming surface 70 (diameter direction surface), a second forming surface opening 76 that opens to the second forming surface 75 (axial surface), and the like. Has. In the present embodiment, the cross-sectional shape of the pressure oil pocket 96 is a rectangular shape having a long side in the axial direction and a short side in the radial direction, but any shape may be used as long as it can be processed. For example, a pressure oil pocket 96a having an L-shaped cross section as shown as a modification in FIG. 11 may be used. The supply path 98 is connected to the bottom surface of the pressure oil pocket 96, and bearing oil is supplied from the supply path 98.

The bearing oil in the pressure oil pocket 96 is supplied to and discharged from the first throttle 92 on the first forming surface 70 (diameter direction surface) and the second drawing 94 on the second forming surface 75 (axial surface). The bearing oil discharged through the second throttle 94 is delivered via the discharge path 90 provided at the central position as seen in FIG. 7 of the shaft support 60. The discharge path 90 of the present embodiment is configured as a common discharge path of the second throttles 94 and 94 on both sides. The bearing oil that has passed through the first throttle 92 is discharged outward from the first throttle 92.

Regarding the relationship between the first diaphragm 92 and the second diaphragm 94, in the present embodiment, the flow resistance of the first throttle 92 and the flow resistance of the second throttle 94 are the same in the thrust direction (axis direction) of the grindstone shaft 54 in a no-load state. It is set to be a distribution conflict. Therefore, when a thrust force in one direction acts on the grindstone shaft 54 and moves in one direction, for example, when a thrust force in the right direction acts on the grindstone shaft 54 and moves in the right direction as seen in FIG. 7, the position on the left side is located. The first throttle 92 formed by the first forming surface 70 (diametrical plane) is in a narrowed state from the no-load state, and the flow resistance is larger than the flow resistance of the second throttle 94 in which the flow resistance does not fluctuate. As a result, the bearing oil is received and supported by the shaft support 60 via the static pressure of the bearing oil stored in the pressure oil pocket 96 formed on the first forming surface 70A (diameter direction surface) of the shaft support 60. In the throttled state of the first throttle 92 of the right step portion y, the flow resistance is smaller than in the no-load state, and the return operation of the grindstone shaft 54 to the left is performed as a reaction to the action of receiving the thrust force at the left side position. It is easy to do. When a thrust force in the left direction is generated on the grindstone shaft 54, the opposite operation is performed.

According to the embodiment of the thrust static pressure bearing 85 described above, the size of the step portion (length in the radial direction), which is a factor that determines the magnitude of the thrust receiving force of the bearing 85, forms the first throttle 92. It is determined by the radial length of the first forming surface 70 (radial surface) and the radial length of the pressure oil pocket 96. As a result, the thrust static pressure bearing 85 can be miniaturized in the radial direction. Therefore, when the external dimensions of the small diameter shaft portion 54B of the grindstone shaft 54 are configured as shown in FIG. 5, the external dimensions of the large diameter shaft portion 54A can be reduced while maintaining the rigidity of the grindstone shaft 54. it can. When the external dimensions of the large-diameter shaft portion 54A can be set to the dimensions shown in FIG. 5, the diameter of the small-diameter shaft portion 54B can be increased, and the overall rigidity can be increased.

The thrust static pressure bearing 85 shown in FIG. 7 of the first embodiment described above is the content previously proposed by the present inventors as Japanese Patent Application No. 2015-14266.

Next, the configuration of the correction force pressurizing unit 62 that generates the correction force of the radial load of the radial static pressure bearing 82 in the pressure oil pocket 96 will be described. FIG. 8 shows the three-dimensional structure of the shaft support 60 in which the pressure oil pocket 96 is formed on the inner peripheral surface, with a part cut off for easy understanding, and FIG. 9 shows the inner peripheral surface of the pressure oil pocket 96. It is shown expanded in the circumferential direction. FIG. 9 is an expanded view of the oil pressure pocket 96 on the right side in FIGS. 5 and 7.

As shown in FIG. 9, the axial widths of the second forming surface opening 76 of the pressure oil pocket 96 constituting the correction force pressurizing portion 62 are different. For example, as shown in FIG. 9, when a correction force is to be generated at a position of 90 ° on the circumference (the F direction indicated by the white arrow in FIG. 8), the correction force is in the range of 0 ° to 180 °. The axial width is formed in L1 and the axial width in the range of 180 ° to 360 is formed in L2. The axial width of L1 is set to be larger than the axial width of L2. That is, it is formed as L1> L2.

FIG. 10 is a chart showing the relationship between the acting forces generated by the above-described configuration. As described above, the acting force P1 of the resultant force generated by the pressure oil supplied to the region formed by L1 and the acting force P2 of the resultant force generated by the pressure oil supplied to the region formed by L2 are the area difference of the region. Therefore, P1> P2. Then, the difference P1-P2 = P3 of this acting force acts as an acting force that receives the radial load of the grindstone shaft 54 as a correction force in the F direction shown in FIG. Reference numeral 97 indicates a pressure oil supply hole to the pressure oil pocket 96.

In the above-described embodiment, the region of L1 is 0 to 180 degrees and the region of L2 is 180 to 360 degrees, but if the resultant force P3 is in the direction of diminishing the force F from the pulley, this angle is set. It may be outside the range. Further, the widths of L1 and L2 (settings of the acting forces P1 and P2 of the resultant force) may be set so that the magnitude of the resultant force P3 is a magnitude that diminishes F. In addition, the reduction means including the case of offsetting.

As described above, the adjustment of the magnitude of the correction force by the correction force pressurizing unit 62 in the first embodiment is performed by adjusting the axial widths L1 and L2 of the second forming surface opening 76 on the circumference of the pressure oil pocket 96. It can be adjusted by changing. The adjustment of the axial widths L1 and L2 has no effect on the bearing force of the thrust static pressure bearing 85.

On the contrary, the radial length of the pressure oil pocket 96 for adjusting the thrust bearing force of the thrust static pressure bearing 85 (the first forming surface 70 (radial surface) including the first forming surface opening 71) is changed. The correction force has no effect on the correction force of the pressurizing unit 62.

Further, the adjustment of the correction force by adjusting the correction force pressurizing unit 62 does not affect the performance of the radial static pressure bearing 82. Therefore, each of them can be adjusted independently, which facilitates the design.

The correction force pressurizing portion 62 of the first embodiment is provided between the small diameter pulley 52 and the radial static pressure bearing 82. According to this configuration, the compensating force pressurizing unit 62 is arranged at a position closer to the small diameter pulley 52 of the radial load generating source than the axial position of the radial static pressure bearing 82. As a result, when the radial static pressure bearing 82 receives the load acting on the small diameter pulley 52, it can be effectively used as a correction force for canceling the radial load based on the principle of leverage.

Next, the second embodiment will be described. The second embodiment is shown in FIGS. 12-14. The second embodiment is an embodiment in which the correction force pressurizing unit 62 is set independently. In the description of the second embodiment, the points different from those of the first embodiment will be mainly described, and the substantially same configuration contents as those of the first embodiment will be described by adding the same reference numerals and the like. Omit.

As shown in FIG. 12, the grindstone shaft 54 of the second embodiment is formed as a shaft having the same diameter, but a large-diameter stepped collar shaft portion 54C is set in the central portion. The shaft support 60, which is a journal at the left and right positions of the collar shaft portion 54C, is provided with a pressure oil pocket 64 of the radial static pressure bearing 82 and a pressure oil pocket 86 of the thrust static pressure bearing 85. A correction force pressurizing portion 62 (pressure oil pocket 96) is provided at 60 positions of the shaft holding body between the shaft support 60 on which the bearings 82 and 85 are formed and the small diameter pulley 52.

The configuration for supplying pressure oil from the oil supply source 66 to the pressure oil pocket 64 and the pressure oil pocket 64 of the radial static pressure bearing 82 of the second embodiment is the same as that of the radial static pressure bearing 82 of the first embodiment described above. It is configured.

The configuration of the thrust static pressure bearing 85 of the second embodiment is different from the configuration in which the correction force pressurizing unit 62 of the first embodiment is combined, and the pressure thereof is the same as the configuration of the general-purpose thrust static pressure bearing. The oil pocket 86 is provided on the opposite surface of the radial surface of both side step portions of the flange shaft portion 54C. A pressure adjusting throttle 99 is provided in the pressure oil supply path to the pressure oil pocket 86 of the thrust static pressure bearing 85 of the present embodiment as in the case of the general-purpose configuration.

The correction force pressurizing portion 62 of the second embodiment is formed on the inner peripheral surface (axial direction surface) of the shaft support 60 shown as a three-dimensional view in FIG. FIG. 14 shows a developed view of the pressure oil pocket 96 formed on the inner peripheral surface (axial surface). The developed view of FIG. 14 is shown in comparison with FIG. 9 of the first embodiment. The shape of the pressure oil pocket 96 in the circumferential direction of the second embodiment is different from that of the first embodiment, but as in the case of the first embodiment, the axis of the circumferential position in the range of 0 ° to 180 °. The directional width is L1, and the axial width in the range of 180 ° to 360 is L2. The axial width of L1 is set to be larger than the axial width of L2, and L1> L2 is formed. As a result, in the second embodiment as well, the correction force is generated in the same manner as in the first embodiment.

In the second embodiment, the supply from the oil supply source 66 to the pressure oil pocket 96 of the correction force pressurizing unit 62 is generated without the pressure adjusting throttle being provided in the supply path. The oil pressure is supplied as it is. Therefore, as compared with the case of the first embodiment, since there is no pressure attenuation due to the passage of the pressure oil through the throttle, a large correction force can be obtained. From the opposite point of view, if the same correction force is obtained, the configuration of the correction force pressurizing unit 62 can be downsized.

Then, also in the case of the second embodiment, as in the case of the first embodiment, the adjustment of the magnitude of the correction force by the correction force pressurizing unit 62 is performed by adjusting the bearing force of the radial static pressure bearing 82 and the thrust static pressure bearing 85. It can be done without affecting the performance of. Therefore, the design and configuration of each bearing becomes easy.

15 to 17 show the relationship between the load direction of the radial load and the action direction of the correction force in the radial static pressure bearing 82 of the first embodiment and the second embodiment. FIG. 15 shows a state in which only the correction force by the correction force pressurizing unit 62 is acting on the grindstone shaft 54 in a state where no radial load is applied. In this state, the grindstone shaft 54 acts on the left side by the action of only the correction force.

FIG. 16 shows a state in which a belt load is applied to the small diameter pulley 52 from the state of FIG. 15 and the belt load and the correction force are balanced. FIG. 17 shows a state in which a belt load is further applied from the state of FIG. 16 and the magnitude of the belt load exceeds the magnitude of the correction force.

Even in the states of FIGS. 15 and 17, it is required that the outer peripheral surface of the grindstone shaft 54 does not come into contact with the inner peripheral surface of the shaft support 60, as described in each of the present embodiments. It is configured.

Although the present invention has been described above with respect to specific embodiments, the present invention can also be implemented in various other embodiments.

For example, in the above-described embodiment, the grinder has been described as a typical example of a machine tool, but it can be applied to various other machine tools.

Further, the relationship between the first throttle and the second throttle in the thrust static pressure bearing in the first embodiment may be a state in which bearing oil flows through the first throttle in a no-load state of the operating member.

Further, it can be widely applied to a device in which an operating member that receives a thrust force is supported by a static pressure thrust bearing.

The position of the correction force pressurizing portion of each of the above embodiments was the position between the small diameter pulley and the radial static pressure bearing, but it can be installed at a position other than such a position.

2 Grinder 10 beds 20 tables 20E encoder (rotation detection means)
20M table drive motor 30 Spindle 31 Spindle 32 Center 31E Encoder (rotation detection means)
31J Spindle rotation axis 31M Spindle motor 33 Drive bracket 40 Mandrel 41 Ram 42 Center 50 Grindstone stand 50E Encoder (rotation detection means)
50M grindstone stand drive motor 51 Large diameter pulley 52 Small diameter pulley (pulley part)
53 Belt 54 Grindstone shaft (rotary shaft body)
54A Large diameter shaft 54B Small diameter shaft 55 Grindstone 55J Grindstone rotation axis 55M Grindstone motor 57 Drainage oil pocket 58 Coolant nozzle 59 Coolant supply pipe 60 Shaft support (journal)
62 Compensation force Pressurizing part 64 Pressure oil pocket 65 Land part 66 Oil supply source 67 Supply path 68 Pressure adjustment throttle 70 1st forming surface 71 1st forming surface opening 75 2nd forming surface 76 2nd forming surface opening 80 Control Equipment 82 Radial static pressure bearing 85 Thrust static pressure bearing 90 Discharge path 91 Grinding stone storage case 92 1st throttle 94 2nd throttle 96 Pressure oil pocket 97 Supply hole 98 Supply path 99 Pressure adjustment throttle x step (left side)
y step (right side)

Claims (6)

Rotating shaft and
A shaft support that rotatably supports the rotary shaft and
A power source that generates the rotational force of the rotating shaft body and
A spindle device including a rotation transmission device for transmitting the rotational force of the power source to a pulley portion provided on the rotation shaft body via a belt.
The shaft support includes a radial static pressure bearing that supports a load in the radial direction of the rotating shaft body, and a correction force pressurizing portion that corrects the bearing force of the radial static pressure bearing.
The radial hydrostatic bearing and the compensating force pressurizing portion are provided at different positions in the axial direction of the rotating shaft body.
The radial static pressure bearing has a plurality of pressure oil pockets in the circumferential direction, and bearing oil is supplied to the pressure oil pockets from an oil supply source via a supply path having a throttle portion.
The compensating force pressurizing portion has one pressure oil pocket in the circumferential direction, and bearing oil is supplied to the pressure oil pocket from an oil supply source via a supply path.
The pocket shape of the hydraulic pocket of the compensating force pressurizing portion is formed to have a different axial width in the circumferential direction, and a compensating force is generated in a direction that diminishes the radial force acting on the rotating shaft body from the pulley portion. A spindle device that is formed as a pocket shape. The spindle device according to claim 1.
The compensating force pressurizing unit has an axial surface facing the rotating shaft body in the radial direction and a radial surface facing the rotating shaft body in the axial direction.
The pressure oil pocket of the compensating force pressurizing portion straddles both surfaces at a corner portion where the axial plane and the radial plane intersect at a position where the thrust load of the rotating shaft body can also be received. It is formed so that the pressure oil pocket on the axial surface generates a correction force, and the pressure oil pocket on the radial surface receives a thrust load, and the pressure oil pocket is an oil supply source. A spindle device in which bearing oil is supplied from a supply path having a throttle portion. The spindle device according to claim 1.
It has an axial surface that is radially opposed to the outer peripheral surface of the rotating shaft body, the pressure oil pocket is formed on the axial direction surface, and an oil supply source is provided in the pressure oil pocket of the correction force pressurizing portion. A spindle device in which the hydraulic pressure generated by the shaft is supplied without going through the throttle section. The spindle device according to any one of claims 1 to 3.
The spindle device in which the compensating force pressurizing portion is set between the pulley portion and the radial static pressure bearing. The spindle device according to any one of claims 1 to 4.
The rotating shaft body has a small diameter portion having a diameter smaller than that of the facing surface between the facing surface with the radial static pressure bearing and the pulley portion, and the compensating force pressurizing portion is set to face the small diameter portion. The spindle device. A grinder provided with the spindle device according to any one of claims 1 to 5.

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