JP2018015826A - Precision hole finishing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure capable of achieving both of accuracy improvement of precision finishing and miniaturization of a precision hole processing device.SOLUTION: A precision hole processing device 1a includes vibration generation means 13 for vibrating in the axial direction, a main spindle 6a supported so as to be able to be rotated or vibrated related to a main spindle head 9a, during precision finishing. The vibration generation means 13 is constituted so as to be driven by an electric motor 10 used in common for driving rotatively the main spindle 6a, and processing is carried out by a hole processing tool fixed to the tip part of the main spindle 6a.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a precision hole finishing device (for example, a one-pass honing machine) for finishing an inner peripheral surface of a circular hole formed in a part or the like of various mechanical devices.

  In many cases, it is necessary to smoothly finish the inner peripheral surface of a circular hole formed in a part or the like of various mechanical devices and to precisely finish the inner diameter of the circular hole. As a processing method used in such a case, processing using a honing tool (for example, one-pass honing using a honing tool) is conventionally known. In the case of turning with a honing tool, while turning the honing tool with hard abrasive grains fixed to the blade, the outer peripheral surface of the honing tool is used to scrape off the inner peripheral surface of the work hole. Finish the inner peripheral surface.

  Conventionally, for example, those described in Patent Documents 1 and 2 are known as precision hole finishing devices used in such cases. FIG. 9 shows the structure of the precision hole finishing device (one-pass honing machine) 1 described in Patent Document 1. In the case of this structure, a workpiece 4 having a circular hole 3 on the table 2 is held via a holder 5 in a state where the circular hole 3 is arranged in the vertical direction. Further, a drilling tool (honing tool) 7 is supported and fixed coaxially with the circular hole 3 at the lower end portion of the main shaft 6 arranged vertically above the workpiece 4. The main shaft 6 is rotatably supported by a main shaft head 9 which can be raised and lowered on the front surface of a column 8 provided on the upper surface of the table 2. When the workpiece 4 is processed, the spindle head 9 moves up and down on the front surface of the column 8.

  When precision finishing is performed 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 performs this circle by so-called one-pass machining in which the hole machining tool 7 is reciprocated once inside the circular hole 3 while pouring a cutting agent (coolant) on the upper surface of the workpiece 4. The inner diameter and surface roughness of the hole 3 are set to desired values.

  In Patent Document 2, in the case of precision finishing as described above, the main shaft (hole drilling tool) is not specifically limited to the axial direction (axial direction, circumferential direction, and radial direction) with respect to the main shaft head. As long as it refers to each direction of the main shaft, the same applies to the entire specification and claims), there is described a precision drilling device provided with vibration generating means for vibrating. According to the precision hole drilling device provided with such vibration generating means, it is possible to cut the chips (chips) generated during processing finely and forcibly discharge the chips to improve the precision of precision finishing. . However, in the case of the precision 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. May be difficult to plan. For this reason, in the case of the precision drilling apparatus 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

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

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

In the case of implementing the precision hole drilling apparatus of the present invention as described above, specifically, the vibration generating means can employ a configuration having a cam member and a rolling member.
When such a configuration is adopted, the cam member is fixed to the main shaft, and on one side surface in the axial direction, a concave portion and a convex portion are smoothly and continuously provided in a circumferential direction centering on the main shaft. A configuration having one cam surface can be employed.
Further, as the rolling member, in a state where the rolling surface provided on the outer peripheral surface is in rolling contact with the cam surface, other members such as each member constituting the cam follower device are arranged with respect to the spindle head. A configuration in which it is rotatably supported can be employed.

In the case of adopting the configuration as described above, for example, the rolling surface of the rolling member has a radial distance from the rotation center axis of the rolling member with respect to the circumferential direction (rotating direction of the rolling member). A configuration with a changing second cam surface can be employed.
When the configuration as described above is employed, specifically, the first cam surface and the first cam surface are adjusted so that the number of vibrations in the axial direction of the main shaft per one rotation of the main shaft is a non-integer number. Regulate 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 amplitude of vibration of the main shaft is not 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 the precision hole drilling apparatus.
The reason why the precision of the precision finishing process can be improved is that 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, the vibration generating means vibrates the main shaft in the axial direction, thereby finely cutting chips (chips) generated during processing and forcing the chips. Can be discharged.
On the other hand, the reason why the precision hole machining apparatus can be reduced in size is that the vibration generating means is driven by a drive source common to the main shaft. That is, in this example, the drive source for driving the main shaft and the drive source for driving the vibration generating means are used as a common drive source, whereby the drive source for the main shaft and the drive source for the vibration generating means are Compared to a configuration in which the slab is provided separately, space saving can be achieved, and the precision hole drilling apparatus can be easily downsized.

The fragmentary sectional view 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, the B section enlarged view of FIG. Similarly, sectional drawing of the cam member which comprises a vibration generation means. Similarly, the orthographic view which shows a cam member in the state seen from the downward direction of FIG. Similarly, the diagram for demonstrating the shape of a cam surface. Similarly, a diagram (a) showing the vibration waveform of the main spindle of one example of the embodiment and a diagram (b) showing the vibration waveform of the main spindle of another example. The fragmentary sectional view (a) for explaining the structure of the 1st example of another example of a cam follower device, and the fragmentary sectional view (b) for explaining the structure of the 2nd example of another example. The partial schematic side view which shows an example of the precision hole finishing apparatus of 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 the present example is for smoothing the inner peripheral surface of the circular hole formed in the parts of various mechanical devices and precisely finishing the inner diameter dimension of the circular hole as in the conventional structure described above. belongs to. Such a precision hole finishing device 1a of this example is configured to reciprocate a hole machining tool (honing tool) 7a one time inside the circular hole 3 of the workpiece 4 (see FIG. 9) (one-pass machining), This is a so-called one-pass honing machine that finishes the inner diameter and surface roughness of the circular hole 3 to desired values. Hereinafter, the structure of the precision hole finishing apparatus 1a of this example will be described. In addition, the up-down direction in each figure does not necessarily correspond with the up-down direction in use condition.

  The precision hole finishing apparatus 1a of this example includes a spindle head 9a, an electric motor 10 as a driving source, a coupling 11, a spindle 6a, a collet chuck 12, a drilling tool 7a, and vibration generating means 13. It has.

Of these, the spindle head 9a is supported so as to be capable of displacement in the axial direction (vertical direction in FIG. 1) with respect to the column 8 (see FIG. 9).
Specifically, the spindle head 9 a includes a case main body 16, a first lid body 19, and a second lid body 20.
The case body 16 is a cylindrical member having both axial ends open.
The first lid body 19 is a substantially ring-shaped member, and is fixed to the case body 16 in a state in which the opening of one end in the axial direction (the upper end in FIG. 1) of the case body 16 is closed. A cylindrical storage cylinder portion 21 that protrudes to the other side in the axial direction is provided over the entire circumference in the radial intermediate portion of the other side surface in the axial direction of the first lid body 19.
On the inner peripheral surface of the other end portion in the axial direction of the storage cylinder portion 21, a lid-side concave portion 22 is formed that is open on the inner side in the radial direction and on the other side in the axial direction.

The second lid 20 is a substantially ring-shaped member, and is fixed to the case body 16 in a state of closing the opening in the other axial end (lower end in FIG. 1) of the case body 16.
The spindle head 9a having the above-described configuration is supported by a part of the column 8 so as to be 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 capable of axial displacement with respect to the column 8. Such an electric motor 10 is for driving a main shaft 6a and vibration generating means 13, which will be described later.

  The coupling 11 is a so-called disk-type coupling in which three cylindrical members 15a, 15b, and 15c are connected in the axial direction. Such a coupling 11 includes a cylindrical member 15a on one end side in the axial direction (upper side in FIG. 1) of the cylindrical members 15a, 15b and 15c, and the other end side in the axial direction (lower side in FIG. 1). ) With the cylindrical member 15c in the axial direction and the radial direction. The cylindrical members 15a, 15b, 15c can be rotated together. In the coupling 11 having the above-described configuration, the cylindrical member 15a on one end side in the axial direction (upper side in FIG. 1) is externally fitted and fixed to the distal end portion (lower end portion) of the output shaft 14 of the electric motor 10. Yes. In this state, the coupling 11 can rotate integrally with the output shaft 14 of the electric motor 10.

  The main shaft 6a is a cylindrical shaft member, and is provided in a state of being inserted through the main shaft head 9a in the axial direction. Among such main shafts 6a, the position of the main shaft side of the rectangular shape in which the shape viewed from the radially outer side is long in the axial direction is located at one position in the circumferential direction of the outer peripheral surface of the portion disposed inside the main shaft head 9a. A recess 17 (see FIG. 2) is formed. A rectangular parallelepiped key member 18 is engaged with the main shaft side recess 17. In this state, a part of the key member 18 protrudes radially outward from the outer peripheral surface of the intermediate portion in the axial direction of the main shaft 6a.

  In the main shaft 6a having the above-described configuration, the outer peripheral surface of one end portion in the axial direction (a portion protruding from the first lid 19 constituting the main shaft head 9a toward the one side in the axial direction) constitutes the coupling 11. Of the cylindrical members 15a, 15b and 15c to be engaged, they are fitted and fixed to the cylindrical member 15c on the other axial end side (the lower side in FIG. 1). Accordingly, the main shaft 6a is displaced relative to the output shaft 14 of the electric motor 10 by the relative motion permissible function of the coupling 11 (in the axial direction described later). (Vibration) is supported in a possible state.

On the other hand, the other axial end portion of the main shaft 6a protrudes from the second lid 20 constituting the main shaft head 9a to the other side in the axial direction.
Further, an intermediate portion in the axial direction of the main shaft 6a is supported in a rotatable state with respect to the main shaft head 9a via a plurality of rolling bearings. Specifically, a portion near one end in the axial direction of the main shaft 6a is rotatably supported by a radial bearing 23 such as a radial ball bearing or a radial slide bearing with respect to the inner peripheral surface of the first lid body 19. doing. The main shaft 6a is supported by the radial bearing 23 so as to be capable of axial displacement. For this reason, in the case of this example, the inner ring constituting the radial bearing 23 is fitted on the outer circumferential surface of the axially intermediate portion of the main shaft 6a so as to be capable of displacement in the axial direction with respect to the main shaft 6a.

  In the case of this example, the main shaft 6a is supported by the main shaft head 9a so that it can vibrate in the axial direction relative to the main shaft head 9a and can be displaced in the axial direction integral with the main shaft head 9a. Has been. For this reason, in the case of this example, the intermediate portion in the axial direction of the main shaft 6a is supported by the main shaft 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 drilling tool 7a to the main shaft 6a.

  The hole machining tool 7a is a rotary tool such as a horn or a reamer, for example, and is formed by bonding 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 part 24 can be constituted by, for example, a plurality of machining part elements (for example, the friction material) provided at a plurality of locations in the circumferential direction of the outer circumferential surface of the hole machining tool 7a.

  The hole machining tool 7a having the above-described configuration is fixed to the main shaft 6a via the collet chuck 12 so that the main shaft 6a can rotate integrally with the main shaft 6a and can be displaced in the axial direction. . Although detailed description is omitted, the precision hole finishing device 1a of this example has a function of expanding and reducing the outer diameter of the processing portion 24 in a state where the hole processing tool 7a is assembled to the main shaft 6a. Yes. For this reason, in the case of this example, the machining portion 24 of the drilling tool 7a has a structure capable of expanding and reducing the outer diameter, and the drilling tool 7a is placed on the spindle in the precision hole finishing device 1a. In the state assembled to 6a, a processing section expanding / contracting means for expanding / contracting the outer diameter of the processing section 24 is provided.

The vibration generating means 13 is driven by the electric motor 10 to vibrate the main shaft 6a supported by the main shaft head 9a in the axial direction.
Specifically, the vibration generating means 13 includes a cam member 25, a track 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 such as SKD11, and includes a fitting cylinder portion 30 and a cam plate portion 31.
The fitting cylinder portion 30 is a cylindrical member, and a key groove 32 (see FIGS. 2 and 4) having both ends in the axial direction and radially inner sides opened at one position in the circumferential direction on the inner peripheral surface. ing. Of the inner peripheral surface of the fitting tube portion 30, the portion other than the key groove 32 is a partial cylindrical surface whose inner diameter does not change over the entire axial length (except for chamfered portions at both axial end edges). It is formed in a shape.

  The cam plate portion 31 is an annular member, and is provided in a state of projecting radially outward from one axial end portion of the outer peripheral surface of the fitting cylinder portion 30 over the entire circumference. A first circumferential groove 33 is formed in the radial intermediate portion of the cam plate portion 31 on one axial side surface (the upper side surface in FIGS. 1 and 4). Yes.

  Of the one side surface in the axial direction of the cam plate portion 31, an annular surface portion formed on the radially outer side than the first circumferential groove 33 is used as a first thrust track surface 34. Such a first thrust raceway surface 34 is constituted by a flat surface located on a virtual plane orthogonal to the central axis of the fitting tube portion 30 (main shaft 6a). Of the one side surface in the axial direction of the cam plate portion 31, a portion (radial outer end portion) positioned radially outward from the first thrust raceway surface 34 extends over the entire circumference on one axial side and the diameter. A cam-side concave portion 35 having an opening on the outer side in the direction is formed. Further, an annular surface portion located on the radially inner side of the first circumferential groove 33 in one axial side surface of the cam plate portion 31 is defined as an inner annular 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.

  An annular first cam surface 37 is formed at the radial intermediate portion of the other side surface in the axial direction of the cam plate portion 31. A second circumferential groove 38 is formed in the radially intermediate portion of the first cam surface 37 and is recessed on the other side in the axial direction over the entire circumference. Therefore, the first cam surface 37 is divided by the second circumferential groove 38 into a radially inner cam surface 39 and a radially outer cam surface 40. The second circumferential groove 38 can be omitted.

In the case of this example, the first cam surface 37 (the inner cam surface 39 and the outer cam surface 40) is smoothed in the circumferential direction by one convex portion (peak portion) and one concave portion (valley portion). The sine wave is continuous. Such first cam surface 37 has 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 on the one side in the most axial direction (upward in FIGS. 1 and 4)). 5 and a position shifted in phase by 180 ° from the lowest point position on the first cam surface 37 (a position opposite to the lowest point position in the radial direction). ) As the highest point position (position indicated by a two-dot chain line β in FIG. 5) located on the other side in the axial direction (the lower side of FIGS. 1 and 4). Two reference positions (positions indicated by two-dot chain lines γ1, γ2 in FIG. 5) that are the center of the highest point position, and a reference point position in which the position in the axial direction is the center position between the lowest point position and the highest point position Therefore, the first cam surface 37 is on the same phase with respect to the circumferential direction. The position in the axial direction has a sine wave shape as shown in Fig. 6 when each reference point position is set to zero (reference point), in this example, from the reference point position to the lowest point position and the highest point. The distance to the point position (sine wave amplitude) is 0.25 mm, and 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 configured in a sinusoidal shape in which one convex portion (peak portion) and one concave portion (valley portion) are smoothly and continuously arranged 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 can be configured in, for example, two sinusoidal shapes in which convex portions (mountain portions) and concave portions (valley portions) are smoothly continuous in the circumferential direction. Further, the shape of the first cam surface is not limited to a sine wave shape, and various wave shapes in which the axial position smoothly changes in the circumferential direction can be adopted.
In addition, 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 configuration is configured such that the fitting tube portion 30 is fitted and fixed to the outer peripheral surface of the intermediate portion in the axial direction of the main shaft 6a, and the key groove 32 of the fitting tube portion 30 is The key member 18 is engaged with the main shaft side recess 17 of the main shaft 6a and is fixed to the main shaft 6a in a state of being key-engaged. Therefore, the cam member 25 can rotate integrally with the main shaft 6a.

  In the case of this example, in order to fix the cam member 25 with respect to the main shaft 6a so as to be able to be displaced in the axial direction in synchronism, the cam member 25 on the outer peripheral surface of the main shaft 6a is fitted outside. A pair of nuts 41 (the nut on the other side in the axial direction is not shown) is screwed and fixed to both sides in the axial direction of the fixed portion. Of the pair of nuts 41, the other axial end of the nut 41 on one axial side and the other axial end surface of the nut on the other axial side are directly or other members (cylindrical spacers). Etc.), both axial end surfaces of the fitting cylinder portion 30 of the cam member 25 are sandwiched in the axial direction. In addition, the structure for fixing the cam member 25 to the main shaft 6a so as to be able to be displaced in the axial direction is not limited to the structure of this example.

  In the assembled state as described above, the outer peripheral surface of the cam plate portion 31 constituting the cam member 25 is in contact with the peripheral surface (bottom portion) of the lid-side concave portion 22 of the storage cylinder portion 21 of the first lid body 19. They are opposed to each other through a slight gap in the radial direction. Further, 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 are opposed to each other via a gap in the axial direction.

The track plate member 26 is a metal ring-shaped member, and a second thrust track surface 42 is formed on the other side surface in the axial direction.
Such a raceway plate member 26 is disposed on the inner side of the storage cylinder portion 21 of the first lid 19 on one side in the axial direction with respect to the cam plate portion 31 in a state capable of axial displacement. Has been. In this state, a plurality of cylindrical rollers 43 constituting the thrust bearing 27 are provided 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. , 43 can be arranged in the bearing arrangement space (axial gap).
Further, a portion of the main shaft 6a where the nut 41 is screwed and fixed is inserted into the inner diameter side of the raceway plate member 26. In this state, a radial gap exists 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 and 43, and an annular holding shape. And a device 44. Specifically, the first thrust raceway surface 34 in a state where the plurality of cylindrical rollers 43, 43 are rotatably held in a plurality of pockets 45, 45 formed in the holder 44. And the second thrust raceway surface 42 are held in the axial direction.

  In the case of this example, an annular plate member 46 is fitted and fixed to one end in the axial direction inside the storage tube portion 21. In this state, one side surface in the axial direction of the annular plate member 46 is in contact with a portion of the other side surface in the axial direction of the first lid 19 that is present on the radially inner side with respect to the storage cylinder portion 21. Yes. 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 annular plate member 46. In the assembled state as described above, a radial gap exists between the inner peripheral surface of the annular plate member 46 and the outer peripheral surface of the main shaft 6a.

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

  As described above, in the case of this example, the annular plate member 46, the biasing member 28, the track plate member 26, the thrust bearing 27, And the one half part of the axial direction of the said cam board part 31 is arrange | positioned. 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 9 a and has a second cam surface 48 that is in rolling contact with the first cam surface 37. Such first cam surface 37 and second cam surface 48 are in elastic 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 includes 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 members, 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 and spaced from each other, and the pair of support wall portions 53 and 53. And a continuous wall portion 54.
A pair of circular holes 55, 55 penetrating through the pair of support wall portions 53, 53 are formed in the matching portions of the pair of support wall portions 53, 53.

  The support shaft 50 is a solid shaft member having a circular cross section, and the pair of support wall portions 53, with both axial end portions fitted and fixed in the pair of circular holes 55, 55, 53. In this state, the support shaft 50 cannot rotate with respect to the pair of support wall portions 53 and 53. In addition, the structure which supports the said support shaft 50 in the state which can rotate with respect to these one pair of support wall parts 53 and 53 is also employable.

The pair of radial ball bearings 51, 51 includes, 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 a 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 rotatably provided between the outer ring raceway and the inner ring raceway.

The cage holds the plurality of balls so as to roll freely.
The pair of seal rings are provided between the inner peripheral surface of both ends in the axial direction of the outer ring and the outer peripheral surface of both ends in the axial direction of the inner ring, and between the inner peripheral surface of the outer ring and the outer peripheral surface of the inner ring. The both ends in the axial direction of the annular inner space where the balls are installed are closed.

  Each of the pair of radial ball bearings 51, 51 having the above-described configuration is such that the inner ring is externally fixed to the outer circumferential surface of the axially intermediate portion of the support shaft 50 by an interference fit. It is fixed to. In this state, the other axial end surface (left end surface in FIG. 1) of the inner ring constituting the radial ball bearing 51 of one of the pair of radial ball bearings 51, 51 (right side in FIG. 1) and the other An axial end surface (left end surface in FIG. 1) of the inner ring constituting the radial ball bearing 51 (left side in FIG. 1) is in contact.

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

  In the case of this example, the outer peripheral surface of the pair of radial ball bearings 51, 51 (each outer ring) is a cylindrical surface, and the central axis of this outer peripheral surface is the support shaft 50 which is the rotation center of each outer ring. The center axis is eccentric (offset) by a predetermined amount. Therefore, in the case of this example, as the outer rings constituting the pair of radial ball bearings 51, 51, the central axis of the outer peripheral surface of each outer ring is the inner peripheral surface (the outer ring raceway) of each outer ring. A structure that is eccentric with respect to the central axis is adopted. The outer peripheral surface of each outer ring is the second cam surface 48. In addition, the outer peripheral surface (second cam surface 48) of each outer ring can be an oval shape or a teardrop shape. Various radial bearings can be used 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 employed. 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 decentered with respect to the rotation center of the second cam surface.

  As described above, in this example, the center axis of the support shaft 50 that is the rotation center axis of the second cam surface 48 is made to coincide with the radial direction with respect to the center 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 virtual 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. 8 (a), a cylindrical roller 63 is provided on the outer peripheral surface in the axial direction intermediate portion of the support shaft 50. A so-called single-roller type that is externally fitted so as to be relatively rotatable with the support shaft 50, or is relatively rotated with the support shaft 50 on the outer peripheral surface in the axial direction intermediate portion of the support shaft 50 as shown in FIG. A so-called double roller is configured such that the first roller 64 is externally fitted and the second roller 65 is externally fitted to 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 a type. When the single roller type configuration is adopted, the central axis of the outer peripheral surface of the roller 63 is also decentered by a predetermined amount with respect to the inner peripheral surface and the central axis of the support shaft 50. 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 similarly decentered by a predetermined amount with respect to the inner peripheral surface and the central axis of the support shaft 50.

  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 (on the right side in FIGS. 2 and 3) has a pair of radial ball bearings 51, 51 in the axial intermediate portion of the support shaft 50. 1 (right side in FIGS. 2 and 3) of the radial ball bearing 51 in the width direction (right side surface in FIGS. 2 and 3) and one of the pair of support wall portions 53 and 53 (see FIG. 2). 2 and the right side of the support wall 53 is fitted on the outer peripheral surface of the portion in the width direction (the left side surface in FIGS. 2 and 3).

  On the other hand, the other of the pair of washers 52, 52 (the left side of FIGS. Of the radial ball bearing 51 on the other side (the left side in FIGS. 2 and 3) in the width direction (the left side surface in FIGS. 2 and 3) and the other of the pair of support wall portions 53 and 53 (see the figure). The outer peripheral surface of a portion between the support wall 53 in the width direction of the second and third support walls 53 (the right side surface in FIGS. 2 and 3) is externally fitted.

  In the cam follower device 29 having the above-described configuration, the support member 49 is supported and fixed inside the case main body 16 constituting the spindle head 9a. In this state, the second cam surface 48 (the outer peripheral surface of each outer ring) is in elastic contact with 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) is based on the pressing force (elastic force) of the urging member 28 and the second cam surface 48. 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) abut ( Based on the rolling contact), each of these outer rings rotates around the central axis of the support shaft 50. In the case of this example, along with the rotation of the second cam surface 48 (the outer peripheral surface of each outer ring) (rotation about the central axis of the support shaft 50), 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 displaces the first cam surface 37 in the axial direction as it rotates (rotates).

  In the case of this example, when it is assumed that no slip occurs in the contact portion (rolling contact portion) between the first cam surface 37 and the second cam surface 48, 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 after one rotation.

  When the cam member 25 rotates together with the main shaft 6a, the vibration generating means 13 having the above-described configuration is configured so that the first cam surface 37 of the cam member 25 and the second cam surface 48 of the cam follower device 29 are provided. The main shaft 6a and the cam member 25 can be vibrated in the axial direction (reciprocating displacement) based on the rolling contact.

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

First, the vibration generated based on the rotation of the first cam surface 37 around 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 urging member 28, when the cam member 25 rotates, Of the one cam surface 37, the portion in contact with the second cam surface 48 moves (rotates) in the circumferential direction. Then, since the first cam surface 37 is formed in a sine wave 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, it vibrates (displaces) only once in the axial direction for each rotation.

Next, the vibration generated based on the rotation of the second cam surface 48 around 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 that is the rotation center of the second cam surface 48. For this reason, the distance from the central axis of the support shaft 50 of the portion of the second cam surface 48 that is in contact (rolling contact) with the first cam surface 37 is the second cam surface 48. It changes as the surface 48 rotates. In the case of this example, the waveform of this change is a sine wave with 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 0.1 to 0.2 mm. The amplitude of this waveform is not limited to this example.

  Accordingly, 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 surface 48 is rotated. The distance from the center axis of the support shaft 50 of 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 (the main shaft 6a) makes one rotation, the vibration generated based on the rotation of the second cam surface 48 around the central axis of the support shaft 50 causes the The cam member 25 (the main shaft 6a) reciprocates 3.5 times (oscillates 3.5 times) in the axial direction.

  As described above, in the case of this example, the main shaft 6a has a vibration waveform of vibration generated based on the rotation of the first cam surface 37 around the central axis of the main shaft 6a (cam member 25), The second cam surface 48 vibrates with a vibration waveform obtained by synthesizing the vibration waveform generated based on the rotation about the central axis of the support shaft 50. In particular, in the case of this example, the first cam is set so that the vibration frequency of the main shaft 6a per 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 restricted. In the case of this example, the shape, size, and contact position of the first cam surface 37 and the second cam surface 48 are restricted so that the amplitude of vibration of the main shaft 6a is not constant. .

  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 of the portion where the first cam surface 37 and the second cam surface 48 are in contact with 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 center axis of the outer peripheral surface of the pair of radial ball bearings 51, 51 is coaxial with the center axis of the support shaft 50 may be employed. When such a configuration is adopted, the main shaft 6a and the cam member 25 are caused to generate vibrations based on the wave shape of the first cam surface 37 as described above, as shown in FIG. It vibrates with the same vibration waveform as.

According to this 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 drilling apparatus.
The reason why the precision of precision finishing can be improved is that the vibration generating means 13 as described above is provided. That is, in the case of this example, when the fine finishing process is performed, the vibration generating means 13 vibrates the main shaft 6a in the axial direction, thereby finely cutting chips (chips) generated during the processing. Can be forcibly discharged.
The reason why the precision hole machining apparatus can be reduced in size is that, in this example, the main shaft 6a and the vibration generating means 13 are driven by the electric motor 10. For this reason, space saving can be achieved as compared with the configuration in which the drive source of the main shaft 6a and the drive source of the vibration generating means 13 are separately provided, and the precision hole drilling apparatus can be easily downsized.

  Further, in the case of this example, the main shaft 6a and the cam member 25 are made to have vibration waveforms of vibrations generated based on the rotation of the first cam surface 37 around the central axis of the main shaft 6a (cam member 25). The second cam surface 48 is configured to vibrate with a vibration waveform obtained by synthesizing a vibration waveform generated based on rotation about the central axis of the support shaft 50. 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. As a result, clogging of the machining portion of the hole machining tool 7a is prevented, and so-called grinds formed on the inner peripheral surface of the circular hole 3 of the workpiece 4 are aligned (lengthened in the axial direction). It can be prevented.

  In particular, in the case of this example, the first cam is set so that the vibration frequency of the main shaft 6a per 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 restricted. For this reason, it can prevent more effectively that the grinding line formed in the internal peripheral surface of the circular hole 3 of the said to-be-processed object 4 aligns (it becomes long in an axial direction).

  Further, in the case of this example, the vibration waveform of the main shaft 6a is made into a combined vibration waveform as described above, and the first cam surface 37 and the second cam surface 37a are set so that the amplitude of the vibration waveform is not constant. The shape, size, and contact position of the cam surface 48 are restricted. That is, the vibration waveform of the main shaft 6a has a portion with a large amplitude and a portion with a small amplitude, as shown in FIG. If there is a portion with such a large amplitude, the machinability can be improved. In addition, since the vibration waveform contains a large amplitude part and a small amplitude part, compared to the case where the amplitude is constant, the effect of cutting finely the chips (chips) generated during processing, The effect of forcibly discharging can be improved.

When the present invention is carried out, the structure of the rolling member is not limited to the structure of the pair of radial ball bearings 51 and 51 constituting the cam follower device 29 described above.
Further, 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.

DESCRIPTION OF SYMBOLS 1, 1a Precision hole finishing apparatus 2 Table 3 Circular hole 4 Work piece 5 Holder 6, 6a Spindle 7, 7a Drilling tool 8 Column 9, 9a Spindle head 10 Electric motor 11 Coupling 12 Collet chuck 13 Vibration generating means 14 Output shaft 15a, 15b, 15c Tubular member 16 Case body 17 Spindle side recess 18 Key member 19 First lid 20 Second lid 21 Storage cylinder 22 Cover body recess 23 Radial rolling bearing 24 Processing section 25 Cam member 26 Track plate member 27 Thrust bearing 28 Biasing member 29 Cam follower device 30 Fitting cylinder portion 31 Cam plate portion 32 Key groove 33 First circumferential groove 34 First thrust raceway surface 35 Cam side recess 36 Inner ring surface 37 Cam Surface 38 Second circumferential groove 39 Inner cam surface 40 Outer cam surface 41 Nut 42 Second thrust raceway surface 4 Cylindrical roller 44 Cage 45 Pocket 46 Annular plate member 48 Second cam surface 49 Support member 50 Support shaft 51 Radial ball bearing 52 Retaining ring 53 Support wall portion 54 Continuous wall portion 55 Circular hole 56 Locking groove 63 Roller 64 First One roller 65 Second roller

Claims (5)

A spindle driven to rotate by a drive source;
A spindle head that supports the spindle in a rotatable and axially viable state; and
A drilling tool fixed to the tip of the spindle;
Vibration generating means for vibrating the main shaft in the axial direction,
The vibration generating means is driven by a drive source common to the main shaft. The vibration generating means has a cam member and a rolling member,
The cam member is fixed to the main shaft, and 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 on one side surface in the axial direction.
2. The precision hole finishing device according to claim 1, wherein the rolling member is rotatably supported with respect to the spindle head in a state in which a rolling surface provided on an outer peripheral surface is in rolling contact with the cam surface. . The precision hole finishing device according to claim 2, wherein the rolling surface of the rolling member is a second cam surface in which a radial distance from the rotation center axis of the rolling member changes in the circumferential direction. The shape and dimensions of the first cam surface and the second cam surface are regulated so that the number of vibrations in the axial direction of the main shaft per one rotation of the main shaft is a non-integer number. The precision hole finishing device described. The precision hole finishing device according to claim 3 or 4, wherein shapes and dimensions of the first cam surface and the second cam surface are regulated so that an amplitude of vibration of the main shaft is not constant.

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