JP6749806B2 - Precision hole finishing device - Google Patents

Description

The present invention relates to a precision hole finishing device (for example, a one-pass honing machine) for finishing the inner peripheral surface of a circular hole formed in parts of various machines and devices.

In many cases, it is necessary to make the inner peripheral surface of a circular hole formed in a component of various mechanical devices smooth and to accurately finish the inner diameter of the circular hole. Processing using a honing tool (for example, one-pass honing using a honing tool) has been conventionally known as a processing method used in such a case. When turning with a honing tool, while rotating the honing tool with hard abrasive grains fixed to the blade part, the outer peripheral surface of this honing tool cuts off the inner peripheral surface of the circular hole of the workpiece, Finish the inner surface of.

As a precision hole finishing device used in such a case, those described in, for example, Patent Documents 1 and 2 have been conventionally known. FIG. 9 shows the structure of a precision hole finishing device (one-pass honing machine) 1 described in Patent Document 1 among them. In the case of this structure, the workpiece 4 having the circular hole 3 on the table 2 is held via the holder 5 with the circular hole 3 arranged vertically. Further, a hole drilling tool (honing tool) 7 is supported and fixed coaxially with the circular hole 3 at the lower end of a spindle 6 arranged vertically above the workpiece 4. The spindle 6 is rotatably supported by a spindle head 9 which is vertically movable on a front surface of a column 8 provided on the upper surface of the table 2. The spindle head 9 moves up and down on the front surface of the column 8 when the workpiece 4 is machined.

When performing precision finishing on the inner peripheral surface of the circular hole 3, the spindle head 9 is lowered while rotating the spindle 6. As a result, the hole machining tool 7 is inserted into the circular hole 3 while rotating, and the inner diameter and surface roughness of the circular hole 3 are finished to desired values. The precision hole finishing device 1 is a so-called one-pass process in which the hole-machining tool 7 is reciprocated once inside the circular hole 3 while pouring a cutting agent (coolant) onto the upper surface of the workpiece 4 to form a circle. The inner diameter and surface roughness of the hole 3 are set to desired values.

In Patent Document 2, when performing the above-described precision finishing, the spindle (hole drilling tool) is not particularly specified in the axial direction (axial direction, circumferential direction, and radial direction) with respect to the spindle head. As long as it refers to each direction of the main shaft, which is the same throughout the present specification and claims, a precision hole drilling device provided with a vibration generating means for vibrating is described. According to the precision hole machining device equipped with such a vibration generating means, the chips (chips) generated during machining can be finely cut and the chips can be forcibly discharged to improve the precision of precision finishing. .. However, in the case of the precision hole drilling device described in Patent Document 2, the drive device for rotationally driving the main shaft and the drive device for driving the vibration generating means are different, so that the precision hole drilling device is downsized. May be difficult to plan. Therefore, in the case of the precision hole drilling device described in Patent Document 2, it is difficult to achieve both improvement in precision of precision finishing and miniaturization.

JP 2004-25416 A JP, 2011-102032, A

In view of the circumstances as described above, the present invention has been devised to realize a structure capable of achieving both improvement in precision of precision finishing and miniaturization.

The precision hole finishing device of the present invention includes a spindle, a spindle head, a hole machining tool, and vibration generating means.
The main shaft is rotationally driven by a drive source.
The spindle head is rotatably the spindle, and supports the vibration in the axial direction in a state capable.
The hole drilling tool is fixed to the tip of the spindle.
The vibration generating means is for vibrating the main shaft in the axial direction, and is driven by a drive source common to the main shaft.

When the precision hole finishing apparatus of the present invention as described above is carried out, specifically, the vibration generating means may have a configuration including a cam member and a rolling member.
When such a configuration is adopted, the cam member is fixed to the main shaft, and the concave portion and the convex portion are smoothly continuous in the circumferential direction around the main shaft on one side surface in the axial direction. A structure having one cam surface can be adopted.
Further, as the rolling member, in a state where a rolling surface provided on an outer peripheral surface is in rolling contact with the first cam surface, with respect to the spindle head (for example, other members of the cam follower device or the like). It is possible to adopt a structure in which the structure is rotatably supported (via the member of FIG.

When the above-mentioned configuration is adopted, for example, at the same position in the circumferential direction around the center axis of the main shaft, the rolling members are adjacent to each other in the radial direction with respect to the center axis of the main shaft. A configuration in which they are individually arranged can be adopted. Further, each of the rolling surface of the rolling member, the radial distance from the rotation center axis of the rolling member is a second cam surface which varies in the circumferential direction (rotation direction of the rolling member) Configuration can be adopted.
When the above-mentioned configuration is adopted, specifically, the first cam surface and the first cam surface are set so that the number of vibrations of the main shaft in the axial direction per one rotation is a non-integer number of times. Control the shape and dimensions of the second cam surface.
Alternatively, the shapes and dimensions of the first cam surface and the second cam surface are regulated so that the vibration amplitude of the main shaft does not become constant.

According to the present invention as described above, it is possible to realize a structure capable of achieving both improvement in precision of precision finishing and miniaturization of a precision hole finishing device.
The reason why the precision of precision finishing can be improved is that a vibration generating means for vibrating the main shaft in the axial direction is provided. That is, in the case of the present invention, at the time of precision finishing, by vibrating the main shaft in the axial direction by the vibration generating means, chips (chips) generated during processing are finely cut and the chips are forced. Can be discharged.
On the other hand, the reason why the precision hole finishing device can be downsized is that the vibration generating means is driven by a drive source common to the main shaft. That is, in the case of the present example, by making the drive source for driving the main spindle and the drive source for driving the vibration generating means a common drive source, the drive source for the main spindle and the drive source for the vibration generating means are Space can be saved and the precision hole finishing device can be easily downsized as compared with the structure in which the separate hole is provided.

The partial cross section figure which shows the precision hole finishing apparatus of one example of embodiment of this invention. Similarly, sectional drawing of the part corresponded to the A section of FIG. Similarly, an enlarged view of part B of FIG. Similarly, sectional drawing of the cam member which comprises a vibration generation means. Similarly, FIG. 5 is an orthographic projection view showing the cam member as seen from below in FIG. 4. Similarly, the diagram for explaining the shape of the cam surface. Similarly, a diagram (a) showing a vibration waveform of a spindle according to an example of the embodiment and a diagram (b) showing a vibration waveform of a spindle according to another example. The partial cross section figure (a) for demonstrating the structure of the 1st example of another example of a cam follower apparatus, and the partial cross section figure (b) for demonstrating the structure of the 2nd example of another example. The partial schematic side view which shows one example of the precision hole finishing device of a conventional structure.

An example of an embodiment of the present invention will be described with reference to FIGS.
The precision hole finishing device 1a of this example has the same inner surface as the circular hole formed in the parts of various mechanical devices, and the inner diameter of the circular hole is precisely finished, as in the conventional structure described above. belongs to. The precision hole finishing apparatus 1a of this example as described above reciprocates the hole machining tool (honing tool) 7a once inside the circular hole 3 of the workpiece 4 (see FIG. 9) (one-pass machining), This is a so-called one-pass honing machine for finishing the inner diameter and surface roughness of the circular hole 3 to desired values. The structure of the precision hole finishing device 1a of this example will be described below. The vertical direction in each drawing does not always coincide with the vertical direction in use.

The precision hole finishing device 1a of this example has a spindle head 9a, an electric motor 10 as a drive source, a coupling 11, a spindle 6a, a collet chuck 12, a hole machining tool 7a, and a vibration generating means 13. Equipped with.

Of these, the spindle head 9a is supported so as to be displaceable in the axial direction (vertical direction in FIG. 1) with respect to the column 8 (see FIG. 9).
Specifically, the spindle head 9a has a case body 16, a first lid body 19, and a second lid body 20.
The case body 16 is a tubular member having both axial ends open.
The first lid body 19 is a substantially circular ring-shaped member, and is fixed to the case body 16 in a state of closing the axially one end (upper end in FIG. 1) opening of the case body 16. At the radial middle portion of the other axial side surface of the first lid body 19 as described above, a cylindrical storage tubular portion 21 is provided that projects over the entire circumference toward the other axial side.
On the inner peripheral surface of the other end in the axial direction of the storage cylinder portion 21, there is formed a lid-side concave portion 22 that is open on the radially inner side and the other axial side over the entire circumference.

The second lid 20 is a substantially ring-shaped member, and is fixed to the case body 16 in a state of closing the axially other end (lower end in FIG. 1) opening of the case body 16.
The spindle head 9a having the above-described structure is supported by a part of the column 8 in a state capable of axial displacement with respect to the column 8.

The electric motor 10 has an output shaft 14, and is supported by a part of the column 8 together with the spindle head 9a so as to be axially displaceable with respect to the column 8. Such an electric motor 10 is for driving a main shaft 6a and a vibration generating means 13, which will be described later.

The coupling 11 is a so-called disc type coupling in which three tubular members 15a, 15b, 15c are axially connected. Such a coupling 11 includes a tubular member 15a at one axial end (upper side in FIG. 1) of the tubular members 15a, 15b, 15c and another axial end (lower side in FIG. 1). 2) has a relative operation permitting function that allows a predetermined amount of relative displacement and relative inclination with respect to the tubular member 15c in the axial direction and the radial direction. Further, the cylindrical members 15a, 15b, 15c can rotate integrally. In the coupling 11 having the above-described structure, the tubular member 15a at one end side (upper side in FIG. 1) in the axial direction is externally fitted and fixed to the distal end portion (lower end portion) of the output shaft 14 of the electric motor 10. There is. In this state, the coupling 11 can rotate integrally with the output shaft 14 of the electric motor 10.

The spindle 6a is a tubular shaft member, and is provided with the spindle head 9a inserted in the axial direction. In such a main shaft 6a, at a position in one position in the circumferential direction of the outer peripheral surface of the portion arranged inside the main shaft head 9a, a rectangular main shaft side whose shape viewed from the outside in the radial direction is long in the axial direction. A recess 17 (see FIG. 2) is formed. A rectangular parallelepiped key member 18 is engaged with the spindle-side recessed portion 17. In this state, a part of the key member 18 projects radially outward from the outer peripheral surface of the axially intermediate portion of the main shaft 6a.

In the spindle 6a having the above-described configuration, the outer peripheral surface of one end portion in the axial direction (the portion protruding from the first lid body 19 constituting the spindle head 9a to the one axial side) constitutes the coupling 11. It is internally fitted and fixed to the tubular member 15c on the other end side (the lower side in FIG. 1) in the axial direction of the tubular members 15a, 15b, 15c. Therefore, the main shaft 6a is displaced in the axial direction by the relative motion permitting function of the coupling 11 with respect to the output shaft 14 of the electric motor 10 by a magnitude permitted by the relative motion permitting function (in the axial direction described later). Vibration) is supported in a state where it is possible.

On the other hand, the other axial end portion of the spindle 6a projects from the second lid body 20 constituting the spindle head 9a to the other axial side.
The axially intermediate portion of the spindle 6a is rotatably supported by the spindle head 9a via a plurality of rolling bearings. Specifically, a portion of the main shaft 6a that is closer to one end in the axial direction is rotatably supported by a radial bearing 23 such as a radial ball bearing or a radial sliding bearing with respect to the inner peripheral surface of the first lid 19. doing. The main shaft 6a is supported by the radial bearing 23 so as to be axially displaceable. For this reason, in the case of this example, the inner ring forming the radial bearing 23 is fitted onto the outer peripheral surface of the axially intermediate portion of the main shaft 6a so as to be axially displaceable with respect to the main shaft 6a.

Further, in the case of this example, the spindle 6a is supported by the spindle head 9a in a state capable of axial vibration with respect to the spindle head 9a and capable of axial displacement integral with the spindle head 9a. Has been done. Therefore, in the case of this example, the axially intermediate portion of the spindle 6a is supported on the spindle head 9a via a so-called stroke bearing (stroke bush, not shown).

The collet chuck 12 is fixed to the other axial end of the main shaft 6a. Such a collet chuck 12 is for fixing the hole drilling tool 7a to the spindle 6a.

The hole-machining tool 7a is, for example, a rotary tool such as a horn or a reamer, and is a machining portion 24 formed by adhering a friction material such as diamond to a part of the outer peripheral surface by an adhesion means such as electrodeposition. have. Such a machining portion 24 can be configured by, for example, a plurality of machining portion elements (for example, the friction material) provided at a plurality of locations in the circumferential direction of the outer peripheral surface of the hole machining tool 7a.

The hole drilling tool 7a having the above-described configuration is fixed to the main shaft 6a via the collet chuck 12 in a state of being integrally rotatable with the main shaft 6a and capable of axially synchronous displacement. .. Although detailed description is omitted, the precision hole finishing device 1a of this example has a function of expanding or contracting the outer diameter of the processing portion 24 in a state where the hole processing tool 7a is assembled to the spindle 6a. There is. For this reason, in the case of the present example, the machining portion 24 of the hole machining tool 7a has a structure capable of expanding and contracting the outer diameter, and the precision hole finishing device 1a is provided with the hole machining tool 7a. In the state of being assembled to 6a, a processing portion expanding/contracting means for expanding/contracting the outer diameter of the processing portion 24 is provided.

The vibration generating means 13 is driven by the electric motor 10 to vibrate the spindle 6a supported by the spindle head 9a in the axial direction.
Specifically, the vibration generating means 13 includes a cam member 25, a raceway plate member 26, a thrust bearing 27, a biasing member 28, and a cam follower device 29.

The cam member 25 is made of, for example, an alloy tool steel material such as SKD11, and has a fitting cylinder portion 30 and a cam plate portion 31.
The fitting tubular portion 30 is a tubular member, and has a key groove 32 (see FIGS. 2 and 4) that is open at both axial ends and radially inward at one position in the circumferential direction on the inner peripheral surface. ing. A portion of the inner peripheral surface of the fitting cylinder portion 30 other than the key groove 32 is a partial cylindrical surface whose inner diameter does not change over the entire length in the axial direction (except for chamfered portions at both axial end edges). It is formed into a shape.

The cam plate portion 31 is a circular ring-shaped member, and is provided in a state of protruding radially outward over the entire circumference from one end portion in the axial direction of the outer peripheral surface of the fitting cylinder portion 30. A first circumferential groove 33, which is recessed toward the other side in the axial direction over the entire circumference, is formed in the radial intermediate portion on one side surface in the axial direction (upper side surface in FIGS. 1 and 4) of the cam plate portion 31. There is.

Of the one side surface in the axial direction of the cam plate portion 31, a ring-shaped surface portion radially outward of the first circumferential groove 33 is defined as a first thrust raceway surface 34. Such a first thrust raceway surface 34 is configured by a flat surface located on an imaginary plane orthogonal to the central axis of the fitting cylinder portion 30 (main shaft 6a). Further, of the one axial side surface of the cam plate portion 31, a portion located radially outward of the first thrust raceway surface 34 (radial outer end portion) has one side in the axial direction and a radial direction over the entire circumference. A cam-side recess 35 is formed that is open on the outside in the direction. Further, of the one axial side surface of the cam plate portion 31, a circular ring surface-shaped portion located radially inward of the first circumferential groove 33 is defined as an inner circular ring surface 36. One end of the key groove 32 in the axial direction is opened at one position in the circumferential direction of the inner ring surface 36.

A circular ring-shaped first cam surface 37 is formed at a radially intermediate portion of the other side surface of the cam plate portion 31 in the axial direction. A second circumferential groove 38, which is recessed toward the other side in the axial direction over the entire circumference, is formed in the radial middle portion of the first cam surface 37. Therefore, the first cam surface 37 is divided by the second circumferential groove 38 into an inner cam surface 39 on the radially inner side and an outer cam surface 40 on the radially outer side. The second circumferential groove 38 may be omitted.

In the case of this example, the first cam surface 37 (the inner cam surface 39 and the outer cam surface 40) has one convex portion (mountain portion) and one concave portion (valley portion) smoothed in the circumferential direction. It has a continuous sine wave shape. Such first cam surfaces 37 have the same position in the axial direction on the same phase in the circumferential direction.
Specifically, the first cam surface 37 has a lowest point position (one position in the circumferential direction of the first cam surface 37 located closest to one axial side (upper side in FIGS. 1 and 4)). The position indicated by the chain double-dashed line α in FIG. 5), and the position of the first cam surface 37 that is 180° out of phase with respect to this lowest point position (position that is opposite to this lowest point position in the radial direction). ) Is the highest point position (the position shown by the chain double-dashed line β in FIG. 5) located on the other side in the axial direction (downward in FIGS. 1 and 4 ). Then, two positions (positions indicated by chain double-dashed lines γ1 and γ2 in FIG. 5) at the center of the lowest point position and the highest point position in the circumferential direction are the positions in the axial direction and the lowest point position. The reference point position is the center position of the highest point position. Therefore, the position of the first cam surface 37 in the axial direction on the same phase in the circumferential direction has a sinusoidal shape as shown in FIG. 6 when the reference point positions are zero (reference points). Becomes In the case of this example, the distance (amplitude of the sine wave) from the reference point position to the lowest point position and the highest point position is 0.25 mm. The surface roughness (arithmetic surface roughness) of the first cam surface 37 is Ra 0.2 or less.

In the case of this example, the first cam surface 37 is formed in a sinusoidal shape in which one convex portion (mountain portion) and one concave portion (valley portion) are smoothly continuous in the circumferential direction. However, the shape of the first cam surface is not limited to the case of this example. For example, the first cam surface may be formed in two sinusoidal shapes in which a convex portion (mountain portion) and a concave portion (valley portion) are smoothly continuous in the circumferential direction. Further, the shape of the first cam surface is not limited to the sine wave shape, and various wave shapes in which the axial position changes smoothly in the circumferential direction can be adopted.
Further, the distance from the reference point position to the lowest point position and the highest point position (the depth of the concave portion and the height of the convex portion from the reference point position) is not limited to the case of this example.

The cam member 25 having the above-described structure externally fits and fixes the fitting cylinder portion 30 on the outer peripheral surface of the main shaft 6a in the axial direction, and the key groove 32 of the fitting cylinder portion 30. The main shaft 6a is fixed to the main shaft 6a in a key-engaged state with the key member 18 engaged with the main shaft-side recessed portion 17. Therefore, the cam member 25 can rotate integrally with the main shaft 6a.

Further, in the case of the present example, in order to fix the cam member 25 with respect to the main shaft 6a so as to be capable of axially synchronized displacement, the cam member 25 of the outer peripheral surface of the main shaft 6a is externally fitted. A pair of nuts 41 (a nut on the other side in the axial direction is not shown) are screwed and fixed to both sides in the axial direction of the fixed portion. Then, of the pair of nuts 41, the other axial end surface of the nut 41 on one axial side and the one axial end surface of the nut on the other axial side also directly or other member (cylindrical spacer). Etc.), the axially opposite end surfaces of the fitting tubular portion 30 of the cam member 25 are sandwiched in the axial direction. The structure for fixing the cam member 25 to the main shaft 6a so as to be capable of axially synchronized displacement is not limited to the structure of this embodiment.

In the assembled state as described above, the outer peripheral surface of the cam plate portion 31 forming the cam member 25 is the same as the peripheral surface (bottom portion) of the lid side concave portion 22 of the housing cylinder portion 21 of the first lid body 19. , Are opposed to each other with a slight gap in the radial direction. The side surface of the lid-side concave portion 22 and the side surface of the cam-side concave portion 35 of the cam plate portion 31 face each other with a gap in the axial direction.

The raceway plate member 26 is a metal ring-shaped member, and has a second thrust raceway surface 42 formed on the other side surface in the axial direction.
Such a raceway plate member 26 is arranged inside the storage cylinder portion 21 of the first lid body 19 in a portion axially one side of the cam plate portion 31 in a state capable of axial displacement. Has been done. In this state, between the first thrust raceway surface 34 of the cam plate portion 31 and the second thrust raceway surface 42 of the raceway plate member 26, a plurality of cylindrical rollers 43 constituting the thrust bearing 27 are provided. , 43, there is a bearing arrangement space (axial gap).
Further, a portion of the main shaft 6a to which the nut 41 is screwed and fixed is inserted into an inner diameter side of the raceway plate member 26. In this state, there is a radial gap between the inner peripheral surface of the raceway plate member 26 and the outer peripheral surface of the nut 41.

The thrust bearing 27 includes a first thrust raceway surface 34 of the cam plate portion 31, a second thrust raceway surface 42 of the raceway plate member 26, a plurality of cylindrical rollers 43, 43, and an annular holding shape. And a container 44. Specifically, in a state in which the plurality of cylindrical rollers 43, 43 are rotatably held in the plurality of pockets 45, 45 formed in the retainer 44, the first thrust raceway surface 34 And the second thrust raceway surface 42 are sandwiched in the axial direction.

In the case of this example, a circular plate member 46 is fitted and fixed to one end portion in the axial direction inside the storage cylinder portion 21. In this state, one side surface in the axial direction of the ring-shaped plate member 46 contacts with a portion of the other side surface in the axial direction of the first lid 19 that is located on the radially inner side of the storage cylinder portion 21. There is. Further, a portion of the main shaft 6a adjacent to one side in the axial direction of the portion to which the nut 41 is fixed is inserted inside the circular plate member 46. In the assembled state as described above, there is a gap in the radial direction between the inner peripheral surface of the annular plate member 46 and the outer peripheral surface of the main shaft 6a.

The urging member 28 can be formed of, for example, a disc spring made of metal. Such a biasing member 28 is disposed between the other axial side surface of the ring-shaped plate member 46 and one axial side surface of the raceway plate member 26. In this state, the biasing member 28 presses the raceway plate member 26, the thrust bearing 27, and the cam member 25 to the other side (downward side) in the axial direction (giving an elastic force). The biasing member 28 is not limited to the disc spring, and various springs and various pressing devices (various pressing devices such as hydraulic type, pneumatic type, mechanical type) can be adopted.

As described above, in the case of this example, the annular plate member 46, the urging member 28, the raceway plate member 26, the thrust bearing 27, inside the storage cylinder portion 21 in this order from one side in the axial direction. Also, one half of one side of the cam plate portion 31 in the axial direction is arranged. With such a configuration, the assemblability of the precision hole finishing device 1a is improved.

The cam follower device 29 is supported and fixed to the spindle head 9a and has a second cam surface 48 that makes rolling contact with the first cam surface 37. The first cam surface 37 and the second cam surface 48 are elastically brought into contact with each other based on the pressing force of the biasing member 28. In the case of this example, the second cam surface 48 corresponds to the rolling surface described in the claims.

Specifically, the cam follower device 29 has a support member 49, a support shaft 50, a pair of radial ball bearings 51, 51, and a pair of washers 52, 52.
Of these, the support member 49 has a substantially U-shaped cross section, and includes a pair of support wall portions 53 and 53 provided in parallel with each other with a space therebetween, and the pair of support wall portions 53 and 53. It has the continuous continuous wall part 54.
A pair of circular holes 55, 55 penetrating the pair of support wall portions 53, 53 is formed in the portions of the pair of support wall portions 53, 53 aligned with each other.

The support shaft 50 is a solid shaft member having a circular cross section, and the pair of support wall portions 53 in a state where both axial end portions are internally fitted and fixed to the pair of circular holes 55, 55. It has been passed over to 53. In this state, the support shaft 50 cannot rotate with respect to the pair of support wall portions 53, 53. It is also possible to employ a structure in which the support shaft 50 is supported in a rotatable state with respect to the pair of support wall portions 53, 53.

The pair of radial ball bearings 51, 51 are, for example, an outer ring (not shown), an inner ring (not shown), a plurality of balls (not shown), a cage (not shown), and a pair of seals. And a ring (not shown).
The outer ring is a member corresponding to the rolling member described in the claims, and has a deep groove type outer ring raceway at an axially intermediate portion of the inner peripheral surface.
The inner ring has a deep groove type inner ring raceway at an axially intermediate portion of the outer peripheral surface.
The plurality of balls are rollably provided between the outer ring raceway and the inner ring raceway.

The cage holds the plurality of balls in a rollable manner.
The pair of seal rings are provided between the inner peripheral surfaces of both axial ends of the outer ring and the outer peripheral surfaces of both axial ends of the inner ring, and between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. , The opening portions at both ends in the axial direction of the annular internal space in which the balls are installed are closed.

Each of the pair of radial ball bearings 51, 51 having the above-described structure has the inner ring fixed to the outer peripheral surface of the intermediate portion of the support shaft 50 in the axial direction by means of an interference fit. It is fixed to. In this state, one of the pair of radial ball bearings 51 (the right side in FIG. 1), the other axial end surface (the left end surface in FIG. 1) of the inner ring forming the radial ball bearing 51, and the other The axial direction one end surface (the left end surface in FIG. 1) of the inner ring forming the radial ball bearing 51 (on the left side in FIG. 1) is in contact.

Further, one of the pair of radial ball bearings 51, 51 (the right side in FIG. 1), the other axial end surface (the left end surface in FIG. 1) of the outer ring forming the radial ball bearing 51, and the other (FIG. 1) (left side of 1) is in contact with one axial end surface (right end surface in FIG. 1) of the outer ring forming the radial ball bearing 51.

In the case of this example, the outer peripheral surfaces of the pair of radial ball bearings 51, 51 (each outer ring) are cylindrical surfaces, and the central axis of the outer peripheral surfaces is the support shaft 50 which is the center of rotation of each outer ring. Is eccentric (offset) with respect to the central axis of. For this reason, in the case of this example, as the outer rings forming the pair of radial ball bearings 51, 51, the central axes of the outer peripheral surfaces of the outer rings are the inner peripheral surfaces of the outer rings (the outer ring raceways). It uses a structure that is eccentric to the central axis. The outer peripheral surface of each outer ring serves as the second cam surface 48. The outer peripheral surface (second cam surface 48) of each of these outer rings can be elliptical or teardrop-shaped. Further, various radial bearings can be adopted instead of the pair of radial ball bearings 51, 51. For example, instead of a pair of radial ball bearings, a single row radial bearing or a double row radial bearing can be adopted. When these configurations are adopted, the outer peripheral surface of the radial bearing is used as the second cam surface, and the central axis of the second cam surface is eccentric with respect to the rotation center of the second cam surface.

As described above, in the case of this example, the central axis of the support shaft 50, which is the central axis of rotation of the second cam surface 48, is aligned with the radial direction with respect to the central axis of the main shaft 6a. Therefore, the rotation center axis of the first cam surface 37 (center axis of the main shaft 6a and the cam member 25) and the rotation center axis of the second cam surface 48 (center axis of the support shaft 50) are orthogonal to each other. (Located on imaginary planes orthogonal to each other).

Further, as a cam follower device, instead of the pair of radial ball bearings 51, 51, as shown in FIG. 8A, a cylindrical roller 63 is provided on the outer peripheral surface of the axial direction intermediate portion of the support shaft 50. A so-called single-roller type externally fitted to the support shaft 50 so as to be rotatable relative to the support shaft 50, or as shown in FIG. 8B, the support shaft 50 is rotated relative to the support shaft 50 on the outer peripheral surface in the axial direction. A so-called double roller in which the first roller 64 is fitted onto the outer surface of the first roller 64 and the second roller 65 is fitted onto the outer peripheral surface of the first roller 64 so as to be rotatable relative to the first roller 64. It is also possible to adopt the type. When the single roller type structure is adopted, the central axis of the outer peripheral surface of the roller 63 is eccentric to the central axis of the inner peripheral surface and the central axis of the support shaft 50 by a predetermined amount. On the other hand, when the double roller type configuration is adopted, the central axis of the outer peripheral surface of the second roller 65 is eccentric to the inner peripheral surface and the central axis of the support shaft 50 by a predetermined amount.

Each of the pair of washers 52, 52 is an annular member made of metal or synthetic resin. One of the pair of washers 52, 52 (right side of FIGS. 2 and 3) has a pair of radial ball bearings 51, 51 in the axially intermediate portion of the support shaft 50. Of the radial ball bearing 51 (on the right side of FIGS. 2 and 3) in the width direction (on the right side of FIGS. 2 and 3), and on one side of the pair of support walls 53, 53 (FIG. It is externally fitted to the outer peripheral surface of the portion between the inner side surface (the left side surface in FIGS. 2 and 3) of the support wall portion 53 (on the right side of 2 and 3).

On the other hand, the other of the pair of washers 52, 52 (left side of FIGS. 2 and 3) has a pair of radial ball bearings 51, 51 in the axially intermediate portion of the support shaft 50. Of the other side (left side of FIGS. 2 and 3) of the radial ball bearing 51 in the width direction outer side surface (left side surface of FIGS. 2 and 3) and the other of the pair of support wall portions 53, 53 (FIG. It is fitted onto the outer peripheral surface of the portion between the inner side surface (the right side surface in FIGS. 2 and 3) of the support wall portion 53 (on the left side of 2 and 3).

In the cam follower device 29 having the above-described configuration, the support member 49 is supported and fixed inside the case body 16 that constitutes the spindle head 9a. In this state, the second cam surface 48 (the outer peripheral surface of each outer ring) elastically contacts the first cam surface 37 (the outer cam surface 40 and the inner cam surface 39). In other words, the first cam surface 37 (the outer cam surface 40 and the inner cam surface 39) has the second cam surface 48 based on the pressing force (elastic force) of the biasing member 28. It is elastically pressed against (the outer peripheral surface of each outer ring). Therefore, when the cam member 25 rotates, the first cam surface 37 (the inner cam surface 39, the outer cam surface 40) and the second cam surface 48 (the outer peripheral surface of each outer ring) come into contact with each other ( Each of these outer rings rotates about the central axis of the support shaft 50 based on the rolling contact). In the case of this example, as the second cam surface 48 (the outer peripheral surface of each outer ring) rotates (rotates about the central axis of the support shaft 50), the second cam surface 48 The distance of the contact portion (rolling contact portion) with the first cam surface 37 from the central axis of the support shaft 50 changes. That is, the second cam surface 48 (the outer peripheral surface of each outer ring) functions as a cam that axially displaces the first cam surface 37 as it rotates (spins).

In the case of the present example, when it is assumed that the contact portion (rolling contact portion) between the first cam surface 37 and the second cam surface 48 does not slip, the main shaft 6a (cam member 25) is The shape and dimensions of each part are regulated so that each outer ring rotates 3.5 times when it makes one rotation.

When the cam member 25 rotates together with the main shaft 6a, the vibration generating means 13 having the above-described structure rotates the first cam surface 37 of the cam member 25 and the second cam surface 48 of the cam follower device 29. Based on the rolling contact with the main shaft 6a and the cam member 25, the main shaft 6a and the cam member 25 can be vibrated (reciprocatingly displaced) in the axial direction.

Specifically, the main shaft 6a and the cam member 25 have a vibration waveform of vibration generated based on the rotation of the first cam surface 37 about the central axis of the main shaft 6a (cam member 25), and The second cam surface 48 vibrates with a vibration waveform that is a combination of the vibration waveform of the vibration generated based on the rotation about the central axis of the support shaft 50.

First, the vibration generated due to the rotation of the first cam surface 37 about the central axis of the main shaft 6a (cam member 25) will be described.
Since the cam member 25 presses the first cam surface 37 against the second cam surface 48 based on the pressing force of the biasing member 28, when the cam member 25 rotates, the A portion of the one cam surface 37 that contacts the second cam surface 48 moves (rotates) in the circumferential direction. Then, since the first cam surface 37 is formed in a sinusoidal shape as shown in FIG. 6, the cam member 25 is based on the shape of the first cam surface 37 along with the movement (rotation). Thus, each rotation causes one reciprocal vibration (displacement) in the axial direction.

Next, the vibration generated by the rotation of the second cam surface 48 about the central axis of the support shaft 50 will be described.
In the case of this example, the central axis of the second cam surface 48 is eccentric with respect to the central axis of the support shaft 50 which is the rotation center of the second cam surface 48. Therefore, the distance of the portion of the second cam surface 48 that is in contact (rolling contact) with the first cam surface 37 from the center axis of the support shaft 50 is the second cam surface. It changes as the surface 48 rotates. In the case of this example, the waveform of this change is a sine wave having a period of 1/3.5 of the period of the waveform (sine wave) of the first cam surface 37. In the case of this example, the amplitude of this waveform is set to 0.1 to 0.2 mm. The amplitude of this waveform is not limited to that of this example.

Therefore, when the second cam surface 48 rotates about the central axis of the support shaft 50 as the cam member 25 rotates, the first cam surface 37 of the second cam surfaces 48 is rotated. The distance from the central axis of the support shaft 50 to the portion that is in contact with (rolling contact with) changes as described above, causing the cam member 25 to vibrate (displace) in the axial direction. In the case of this example, when the cam member 25 (main shaft 6a) makes one rotation, the vibration is generated based on the rotation of the second cam surface 48 about the central axis of the support shaft 50. The cam member 25 (the main shaft 6a) reciprocates 3.5 times in the axial direction (vibrates 3.5 times).

As described above, in the case of the present example, the main shaft 6a has a vibration waveform of the vibration generated based on the rotation of the first cam surface 37 about the central axis of the main shaft 6a (cam member 25), It vibrates with a vibration waveform that is a combination of the vibration waveform of the vibration generated based on the rotation of the second cam surface 48 about the central axis of the support shaft 50. Particularly, in the case of the present example, the first cam is configured so that the frequency of the main shaft 6a per one rotation of the main shaft 6a (cam member 25) is a non-integer number of times (for example, 3.5 times). The shape, size, and contact position of the surface 37 and the second cam surface 48 are regulated. Further, in the case of this example, the shapes, dimensions, and contact positions of the first cam surface 37 and the second cam surface 48 are regulated so that the vibration amplitude of the main shaft 6a is not constant. ..

Incidentally, FIG. 7A shows an example of the vibration waveform of the main shaft 6a. However, the vibration waveforms of the main shaft 6a and the cam member 25 are such that the phase of the first cam surface 37 and the second cam surface of the portion where the first cam surface 37 and the second cam surface 48 contact each other. The waveform varies depending on the phase of the surface 48.

Instead of the cam follower device 29, a cam follower device in which the central axes of the outer peripheral surfaces of the pair of radial ball bearings 51, 51 are coaxial with the central axis of the support shaft 50 can be adopted. When such a configuration is adopted, the main shaft 6a and the cam member 25 vibrate based on the above-described wave shape of the first cam surface 37 as shown in FIG. 7B. It vibrates with the same vibration waveform as the vibration waveform of.

According to the present example having the above-described configuration, it is possible to realize a structure capable of achieving both improvement in precision of precision finishing and miniaturization of the precision hole finishing device.
The reason why the precision of the precision finishing can be improved is that the vibration generating means 13 as described above is provided. That is, in the case of the present example, at the time of precision finishing, by vibrating the main shaft 6a in the axial direction by the vibration generating means 13, chips (chips) generated during processing are finely cut and Can be forcibly discharged.
Further, the reason why the precision hole finishing device can be miniaturized is that, in the case of the present example, the main shaft 6a and the vibration generating means 13 are driven by the electric motor 10. Therefore, as compared with the structure in which the drive source of the main shaft 6a and the drive source of the vibration generating means 13 are separately provided, space can be saved and the precision hole finishing device can be easily downsized.

Further, in the case of the present example, the main shaft 6a and the cam member 25 have a vibration waveform of vibration generated based on the rotation of the first cam surface 37 about the central axis of the main shaft 6a (cam member 25). The vibration waveform of vibration generated based on the rotation of the second cam surface 48 about the center axis of the support shaft 50 is combined to vibrate. Therefore, the main shaft 6a and the cam member 25 can be vibrated with a vibration waveform that is not synchronized with the rotation of the main shaft 6a as shown in FIG. 7(a). As a result, it is possible to prevent clogging of the machined portion of the hole-machining tool 7a and to align so-called ground lines formed on the inner peripheral surface of the circular hole 3 of the workpiece 4 (become longer in the axial direction). Can be prevented.

Particularly, in the case of the present example, the first cam is configured so that the frequency of the main shaft 6a per one rotation of the main shaft 6a (cam member 25) is a non-integer number of times (for example, 3.5 times). The shape, size, and contact position of the surface 37 and the second cam surface 48 are regulated. Therefore, it is possible to more effectively prevent that the grits formed on the inner peripheral surface of the circular hole 3 of the workpiece 4 are aligned (become elongated in the axial direction).

Further, in the case of the present example, the vibration waveform of the main shaft 6a is set to the above-described combined vibration waveform, and the first cam surface 37 and the second cam surface 37 are formed so that the amplitude of the vibration waveform is not constant. The shape, size, and contact position of the cam surface 48 are regulated. That is, in the vibration waveform of the main shaft 6a, as shown in FIG. 7A, there are a portion having a large amplitude and a portion having a small amplitude. The presence of such a large amplitude portion can improve the machinability. In addition, since the vibration waveform contains a part with a large amplitude and a part with a small amplitude, compared to the case where the amplitude is constant, the effect of finely cutting the chips (chips) generated during processing and the effect of cutting this chip The effect of forced discharge can be improved.

When carrying out the present invention, the structure of the rolling member is not limited to the structure of the pair of radial ball bearings 51, 51 constituting the cam follower device 29 described above.
The structure of the cam surface is not limited to the structure of the first cam surface 37 described above.
Further, the present invention can be applied not only to the one-pass honing machine as in the example of the above-described embodiment, but also to a precision hole finishing device having various structures.

1, 1a Precision hole finishing device 2 Table 3 Circular hole 4 Workpiece 5 Holder 6, 6a Spindle 7, 7a Hole machining tool 8 Column 9, 9a Spindle head 10 Electric motor 11 Coupling 12 Collet chuck 13 Vibration generating means 14 Output shafts 15a, 15b, 15c Cylindrical member 16 Case body 17 Main shaft side recessed part 18 Key member 19 First lid 20 Second lid 21 Storage cylindrical part 22 Lid side recessed part 23 Radial bearing 24 Processing part 25 Cam member 26 Raceway plate member 27 Thrust bearing 28 Biasing member 29 Cam follower device 30 Fitting cylinder part 31 Cam plate part 32 Key groove 33 First circumferential groove 34 First thrust raceway surface 35 Cam side recessed part 36 Inner ring surface 37 Cam surface 38 Second peripheral groove 39 Inner cam surface 40 Outer cam surface 41 Nut 42 Second thrust raceway surface 43 Cylindrical roller 44 Retainer 45 Pocket 46 Ring-shaped plate member 48 Second cam surface 49 Support member 50 Support shaft 51 Radial Ball bearing 52 Washer 53 Support wall portion 54 Continuous wall portion 55 Circular hole 56 Locking groove 63 Roller 64 First roller 65 Second roller

Claims (3)

A spindle driven by a drive source,
A spindle head that supports the spindle in a rotatable and axially vibrable state;
A hole machining tool fixed to the tip of the spindle,
And a vibration generating means for vibrating the main shaft in the axial direction,
The vibration generating means, I der are driven by a common driving source and the main shaft has a cam member and a rolling member,
The cam member is fixed to the main shaft, and on one side surface in the axial direction, has a first cam surface in which a concave portion and a convex portion are smoothly continuous in a circumferential direction around the main shaft,
The rolling member is rotatably supported with respect to the spindle head in a state where a rolling surface provided on an outer peripheral surface is in rolling contact with the cam surface.
A precision hole finishing device,
Two rolling members are arranged adjacent to each other in the radial direction with respect to the central axis of the main shaft at the same position in the circumferential direction around the central axis of the main shaft,
A precision hole finishing device in which each rolling surface of the rolling member is a second cam surface whose radial distance from the rotation center axis of the rolling member changes in the circumferential direction . As the number of vibrations in the axial direction of the main shaft per revolution of the main shaft is a non-integer times, to claim 1 where the shape and dimensions of said first cam surface and the second cam surface is restricted Precision hole finishing device described. The precision hole finishing device according to claim 1 or 2 , wherein the shapes and dimensions of the first cam surface and the second cam surface are regulated so that the vibration amplitude of the main shaft does not become constant.

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