JP2007064863A - Inspection device and inspection method for nut constituting ball screw mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inspect a nut constituting a ball spring while cooperated with a screw shaft and a bearing ball, as a single body. <P>SOLUTION: An inspecting spherical body 92 is supplied into a circulation route through a supply passage 96, using a shaft-like tool 54 formed with a screw groove 90 to be engaged with the nut 12, and having the supply passage 96 opened toward the circulation route, and vibration of the spherical body is detected when passed through a communication passage 36. Being inspected using the tool, the nut is not required to bed combined with the screw shaft and the bearing ball, and can be inspected as the single body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an inspection device and an inspection method for a nut that constitutes a ball screw mechanism in cooperation with a screw shaft and a bearing ball.

The ball screw mechanism is used in various apparatuses and devices as being capable of realizing smooth motion conversion. Generally, a ball screw mechanism has a plurality of bearing balls engaged with thread grooves formed in a screw shaft and a nut, and the bearing balls circulate in response to relative rotation between the screw shaft and the nut. It is structured to move along. In order to form the circulation path, it is necessary to form a communication path that connects two locations of the spiral path formed by the thread groove of the nut and the thread groove of the screw shaft. Is provided. In the following patent document, as an example, a ball screw mechanism including a nut in which a deflector functioning as a communication path forming portion is mounted on a nut body is described.
JP 2004-138179 A JP 11-270648 A

  In the ball screw mechanism described in the above-mentioned patent document, as one factor that hinders smooth operation, a step that occurs at the boundary between the deflector and the nut main body due to processing accuracy and the like is described. That is, in the nut constituting the ball screw mechanism, a situation occurs in which the smooth movement of the bearing ball is not sufficiently ensured at the transition point from the spiral path to the communication path or from the communication path to the spiral path. The possibility is high. When such a situation occurs, a phenomenon that the ball screw mechanism itself vibrates, a phenomenon that abnormal noise is generated from the ball screw mechanism, and the like appear.

  Conventionally, the inspection regarding the smoothness of the operation of the ball screw mechanism is to detect the vibration of the finished product, the sound generated by the finished product, etc., for the finished product already assembled with the screw shaft, nut and bearing ball. Was done by. When there are factors in the nut that hinder smoothness as described above, when the inspection is performed according to the conventional method and it is recognized that the finished product is not of sufficient quality, the finished product is once disassembled. Then, it was necessary to replace the nut and recombine, and to inspect the completed body with the replaced nut again. The disassembly and re-combination of this finished product was a burden in the manufacturing process of the ball screw mechanism. The present invention has been made in view of such circumstances, and it is an object of the present invention to provide an apparatus and method for inspecting a nut constituting a ball screw mechanism alone, not a ball screw mechanism as a finished product. And

  In order to solve the above-described problems, a nut inspection device according to the present invention includes a shaft-shaped jig having a supply path that is threaded and fitted into a nut and opens to a circulation path, and circulates through the supply path. The nut inspection method of the present invention is characterized by comprising a sphere supplied into the road and a wave detector for detecting vibration and sound when the sphere passes through the communication path. Is fitted to the nut so that a circulation path is formed, the sphere is supplied into the circulation path through the supply path, and vibration and sound are detected when the sphere passes through the communication path. Features.

  In the present invention, a jig corresponding to a screw shaft having a supply path capable of supplying a sphere to the circulation path is employed to inspect for vibration and sound caused by the nut. Therefore, according to the present invention, the nut can be inspected alone without being combined with the screw shaft and the bearing ball.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which some constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention.

  In each of the following items, (1) corresponds to claim 1, (2) corresponds to claim 2, and (3) and (4) combine to claim 3. , (8) and (9) are equivalent to claim 4, respectively. The (21) term corresponds to claim 5, the (22) term corresponds to claim 6, and the (23) term corresponds to claim 7.

(1) A nut that constitutes a ball screw mechanism in cooperation with a screw shaft and a bearing ball, and is formed by its own screw groove and a screw groove of the screw shaft so as to form a circulation path of the bearing ball. An inspection device for inspecting a nut provided with a communication path forming part for forming a communication path for communicating two locations of a spiral path with each other,
A screw groove corresponding to the screw groove of the screw shaft is provided, and is fitted into the nut so as to form the circulation path, and has a supply path provided inside itself and opening to the circulation path. A shaft jig;
One or more spheres corresponding to the bearing balls supplied from the supply path into the circulation path;
A nut inspection device comprising: a wave detector that detects a generated wave that is at least one of sound and vibration generated when the one or more spheres supplied to the circulation path pass through the communication path.

  The nut inspection apparatus according to the aspect described in this section is simply a jig corresponding to a screw shaft fitted to a nut, and a sphere corresponding to a bearing ball is formed in a circulation path formed by the nut. A jig provided with a supply path that can be supplied is adopted, and the sphere is supplied to the circulation path from the supply path in a state in which a nut is fitted to the jig, and the supplied sphere is a part of the circulation path. It is a device that enables inspection of nuts by detecting vibration and sound when passing through a certain communication path. Therefore, according to the device of the aspect of this section, it is possible to inspect the nut in a single state without making the finished body combined with the screw shaft and the bearing ball.

  The “nut” to which the aspect of this section is applied is a deflector-type nut, for example, a deflector (also referred to as a “piece”) for forming a communication path so that a bearing ball returns to an adjacent screw groove. ), Or an outer circulation type (return pipe type) nut, for example, a communication path is formed so that the bearing ball returns by bypassing a plurality of pitch grooves. It may be a nut.

  The “shaft-shaped” jig in this aspect preferably has the same screw groove as the screw shaft combined with the nut to be inspected. The “supply path” can be, for example, a path having one end opened in a thread groove formed in the shaft-shaped jig and the other end opened in one end of the shaft-shaped jig. In this case, the supply path is not a straight line, but is a path that is generally bent or curved. In the case of such a supply path, the thread groove provided in the shaft-shaped jig in the radial direction of the shaft-shaped jig so that the movement of the sphere from the opening to the thread groove to the circulation path is smooth. It is desirable that the passage be asymptotic to In addition, for example, when the shaft-shaped jig has a solid structure, the supply path may be configured as a passage hole provided through the shaft-shaped jig. In the case where the tool has a cylindrical jig main body in which a thread groove is formed, the tool may be configured to include a tubular passage forming member disposed inside the jig main body.

  The “sphere” in the aspect of this section may be a bearing ball itself combined with a nut to be inspected, or a sphere having the same diameter as or slightly different from the bearing ball. A ball of the same material as the ball or a different material may be used. When a plurality of spheres are used, they may exist as a single body, or may be connected to each other as will be described later. Moreover, in the aspect of this term, the means for supplying the sphere is not particularly limited. It can be supplied by human power or can be supplied using gravity, and can be supplied by applying a propulsive force or a driving force to the sphere by some mechanism or device.

  The specific configuration of the “wave detector” in the aspect of this section is not particularly limited, and an appropriate one is selected and adopted depending on whether the detected wave is vibration or sound. It is possible. For example, it is possible to employ a piezoelectric accelerometer or the like when detecting vibration, and various microphones or the like when detecting sound. In the inspection using the inspection apparatus according to the aspect of this section, when the wave level (for example, intensity, amplitude, etc.) detected by these detectors exceeds the set threshold, the nut to be inspected is defective. It is possible to carry out inspections that certify that The term “sound and vibration generated when a sphere passes through the communication path” in this section does not mean only the sound or vibration generated when the sphere passes through the communication path. It is a concept that includes sound and vibration generated when moving from a road to a communication path or from a communication path to a spiral path, that is, when a sphere passes through the boundary between the communication path and the spiral path.

(2) The shaft-shaped jig is
Provided inside itself, provided with a discharge path for discharging the one or more spheres supplied into the circulation path, opening to the circulation path on the opposite side of the supply path across the communication path (1) Nut inspection device.

  According to the aspect of this section, for example, a one-way passage of the sphere can be formed. As a result, for example, it is possible to easily perform inspections and the like performed by passing the communication path by injecting the sphere, and the sphere can be easily collected. The “discharge path” in the aspect of this section is similar to the supply path described above, for example, one end opens in a screw groove formed in the shaft-shaped jig and the other end opens in one end portion of the shaft-shaped jig. It can be a passage. In this case, as in the case of the supply path, the sphere from the circulation path to the thread groove is gradually moved from the thread groove provided on the shaft jig in the radial direction of the shaft jig so as to move smoothly. It is desirable that the passage be far away. Similarly to the supply path, for example, when the shaft-shaped jig has a solid structure, it may be configured as a passage hole provided through the shaft-shaped jig. In the case where the jig has a cylindrical jig body in which a thread groove is formed, the jig may include a tubular passage forming member disposed inside the jig body. Good.

(3) The nut inspection device
The nut inspection device according to (1) or (2), further comprising a spherical body feeding device that feeds the one or more spherical bodies into the circulation path through the supply path.

  The mode of this section is a mode provided with a device capable of supplying a sphere with a propulsive force, a driving force, etc. supplied thereto. The structure of the “sphere feeding device” in the aspect of this section is not particularly limited. For example, a member that engages with a sphere, such as a piston, a rotating belt, and a rotating drum, is provided, and the member is operated, and the structure is configured to apply propulsive force and driving force to the sphere with the operating force. Is possible. Moreover, it can also be set as the structure which gives a propulsive force and a driving force to a spherical body with the pressure, magnetic force, etc. of fluid, such as gas and a liquid. The sphere feeding device may be configured to inject a sphere and supply it to the circulation path. When a plurality of spheres are used, the plurality of spheres are sequentially pushed into the supply path. The plurality of spheres may be connected in a daisy chain and supplied to the circulation path.

  (4) The nut inspection device according to (3), wherein the sphere feeding device feeds the one or more spheres using compressed gas.

  The mode described in this section is a mode in which the structure of the spherical body feeding device is limited. If the gas pressure is used, the structure of the sphere feeding device can be simplified. Further, there is an advantage that the feeding speed of the sphere can be easily changed by controlling the pressure of the compressed gas. If the sphere feeding device according to the aspect of this section is adopted, it is possible to inject a sphere, and it is also possible to supply a plurality of spheres in a daisy chain.

  (5) The one or more spheres according to any one of (1) to (4), wherein each of the one or more spheres includes a plurality of spheres corresponding to the bearing balls, and the plurality of spheres are connected in a bead shape. Nut inspection device.

  The aspect described in this section is an aspect in the case of employing a plurality of spheres, and is an aspect in which a plurality of spheres actually connected in a rosary are employed. In the case of using a plurality of spheres, the spheres can be handled easily, for example, supplied to the circulation path, discharged from the circulation path, etc. by connecting the plurality of spheres in a bead shape as in the aspect of this section. Will get.

  (6) The nut inspection apparatus is an inspection apparatus for inspecting the nut having a nut main body provided with a thread groove and a deflector mounted on the nut main body and functioning as the communication path forming portion (1 The nut detection device according to any one of items) to (5).

  When a deflector-type nut is employed, the movement of the bearing ball often lacks smoothness in the communication path, that is, the portion of the circulation path where the path of the bearing ball is changed by the deflector. According to the aspect of this section, it is possible to inspect a deflector-type nut that matches such a situation.

  (7) The nut inspection device is an inspection device for performing an inspection on the generated wave generated due to a step existing at a boundary between the deflector and the nut body (1) to (6) The nut inspection device according to any one of the items).

  In the deflector-type nut, a step is generated at the boundary between the nut body and the deflector due to processing accuracy and the like, and this step is a cause of hindering the smooth operation of the ball screw mechanism. In the aspect of this section, it is possible to perform inspection of a deflector type nut in consideration of such a situation.

(8) The nut inspection device is
It is an apparatus for inspecting the nut in which a plurality of the circulation paths are formed by providing a plurality of the communication path forming portions, each including a plurality of the supply paths corresponding to each of the plurality of circulation paths. The nut inspection device according to any one of items (1) to (7)

  For example, many of the deflector type nuts are provided with a plurality of deflectors. The aspect of this section is an aspect of an inspection apparatus that inspects a nut provided with such a plurality of communication passage forming portions. According to the aspect of this section, since the generated waves in the plurality of communication passage forming portions can be detected at one time, it is possible to quickly inspect the nut provided with the plurality of communication passage forming portions. In the aspect of this section, it is possible to provide a plurality of the above-described discharge paths corresponding to the respective circulation paths, that is, corresponding to the respective supply paths.

(9) The nut inspection device is
The nut inspection apparatus according to item (8), wherein each of the plurality of wave detectors corresponds to each of the plurality of circulation paths.

  The aspect of this section is an aspect in which, for example, each of the plurality of wave detectors is arranged in the vicinity of each of the communication path forming portions corresponding to the communication path forming portions constituting each of the plurality of circulation paths. It can be. With such an aspect, it is possible to separately detect the generated wave in each of the plurality of communication passage forming portions, and the place where the smoothness of the operation of the ball screw mechanism is impeded, in other words, which communication passage formation is performed. It is possible to specify whether or not the smooth movement of the bearing ball is hindered in the portion.

(21) A nut that constitutes a ball screw mechanism in cooperation with the screw shaft and the bearing ball, and is formed by its own screw groove and the screw groove of the screw shaft so as to form a circulation path of the bearing ball. An inspection method for inspecting a nut provided with a communication path forming portion for forming a communication path for communicating two portions of a spiral path with each other,
A shaft-shaped jig provided with a thread groove corresponding to the thread groove of the screw shaft and provided with a supply path that opens to the thread groove is formed so that the circulation path is formed and the supply path is the circulation path. A setting step for fitting the nut,
A sphere supply step of supplying one or more spheres corresponding to the bearing balls into the circulation path through the supply path;
And a wave detecting step of detecting a generated wave that is at least one of sound and vibration generated when the one or more spheres supplied to the circulation path pass through the communication path.

  The aspect described in this section is an aspect in which the category is an inspection method. According to the inspection method of the aspect of this section, the nut constituting the ball screw is not combined with the screw shaft and the bearing ball into a complete body. It becomes possible to inspect in a single state. For example, the aspect of this section can be easily realized by using the inspection apparatus of the above aspect. Since the description of the aspect of this section overlaps with the description of the inspection apparatus, the description thereof is omitted here. It should be noted that the technical features employed in the various aspects related to the above-described inspection apparatus can be arbitrarily added to the inspection methods below this section including this section.

(22) The wave detection step includes
In a state where the one or more spheres are present in the circulation path, the nut and the shaft-shaped jig are relatively rotated, and the one or more spheres in the circulation path are moved by the relative rotation. The nut inspection method according to item (21), including a step of detecting the generated wave.

  The aspect of this section is an aspect in which a specific method of the inspection method is limited. Simply put, for example, this is an inspection method in which a plurality of spheres are supplied into a circulation path and the nut and the shaft-shaped jig are rotated relative to each other while they are retained in the circulation path. According to the inspection method of this aspect, the nut can be inspected in a state close to the state in which the ball screw mechanism is actually used. In addition, as an inspection apparatus for executing the inspection method according to the aspect of this section, the inspection apparatus can be configured to include a relative rotation device that relatively rotates the nut and the shaft-shaped jig.

(23) The sphere supply step includes a step of passing each of the one or more spheres through the communication passage while sequentially supplying the spheres into the circulation passage.
The nut inspection method according to item (21), wherein the wave detection step includes a step of detecting the generated wave every time the one or more spheres pass through the communication path.

  The aspect of this section is an aspect in which a specific method of the inspection method is limited. The mode of this section differs from the above mode in that the sphere is not retained in the circulation path, for example, the sphere is passed through the communication path by the action of the sphere feeding device, and the generated wave at the time of the passage is detected. This is the mode. According to the aspect of this section, since it is not necessary to relatively rotate the nut and the shaft-shaped jig, a simple inspection is realized.

  Hereinafter, embodiments of the claimable invention and modifications thereof will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention is implemented in various modes including various modifications and improvements based on the knowledge of those skilled in the art, including the mode described in the above [Mode of Invention]. can do.

<Nut and ball screw mechanism composed thereof>
FIG. 1 shows a ball screw mechanism constituted by a nut to be inspected in a nut inspection device of this embodiment and a nut inspection method using the device. The ball screw mechanism includes a screw shaft 10, a nut 12, and a bearing ball 14 for screwing them together, and is configured by cooperation thereof. The screw groove 16 formed in the screw shaft 10 and the screw groove 18 formed in the nut 12 form a spirally extending passage through which the bearing ball 14 can pass, that is, a spiral path.

  However, since the nut 12 is a deflector-type nut in which four deflectors 22 are attached to the nut main body 20 in which the screw groove 18 is formed, in the present ball screw mechanism, the four deflectors 22 provide four nuts. A circulation path 24 is formed, and the bearing ball 14 circulates through each of the four circulation paths 24. In FIG. 1, only two deflectors 22 positioned at the upper and lower positions in the drawing of the nut 12 are shown, and the other two deflectors 22 are the front side and the back side in the direction perpendicular to the paper surface of the screw shaft 10. And is located in each. What is located on the near side is located in the middle of the two deflectors 22 shown in the left-right direction in the figure (hereinafter sometimes referred to as “axial direction”), and is located on the far side. Is located on the right side of what is located below. Similarly, the bearing ball 14 is only present in two circulation paths 24 corresponding to two deflectors 22 positioned above and below the four circulation paths 24. By the way, in the following description, when each of the four deflectors 22, the four circulation paths 24, and the corresponding components are called, the deflectors 22a to 22 are sequentially arranged from the left to the right in the axial direction. 22d, circulation paths 24a to 24d, and the like are referred to with suffixes a to d.

  FIG. 2 is a sectional view of the nut 12 alone, and can be considered as a view showing a state in which the screw shaft 10 and the bearing ball 14 are removed from the ball screw mechanism shown in FIG. FIG. 3 is a four-view drawing showing the deflector 22 and one cross-sectional view (showing the AA cross-section in the figure). As can be seen from these drawings, the deflector 22 has a generally elliptical cylindrical shape with a low profile, and a through hole 30 through which the bearing ball 14 can pass along a three-dimensional curved path has It is formed on the side opposite to the back surface on which the portion 32 is provided. Four deflector holes 34 are formed in the nut main body 20 so as to penetrate the peripheral wall of the nut main body 20, and the deflector 22 is fitted in each of the four deflector holes 34. By fitting such a deflector 22, a communication path 36 that connects two locations adjacent to each other in the axial direction of the spiral path is formed, and as a result, the above-described circulation path 24 is formed (see FIG. 1). . That is, the deflector 22 functions as a communication path forming portion that forms the communication path 36 in the nut 12. The deflector 22 is a single component, but may be configured by combining two components.

  The nut 12 has a structure in which the deflector 22 is fitted into the deflector hole 34. Therefore, depending on the dimensional accuracy of the deflector 22, the accuracy of forming the deflector hole 34, etc., a step may occur at the boundary between the deflector 34 and the nut body 20. This step is a transition point from the part other than the communication path 36 in the circulation path 24 (hereinafter sometimes referred to as “non-communication path part”) to the communication path 36 or from the communication path 36 to the non-communication path part. G (see FIG. 2), when the bearing ball 14 passes through the portion, the step difference interferes with it, and the smooth movement of the bearing ball 14 is impaired, and the vibration of the ball screw mechanism , Noise from the ball screw mechanism is generated. In view of such circumstances, the inspection of the ball screw mechanism is performed by detecting the presence or absence of the above-described phenomenon that occurs when the bearing ball 14 passes through the communication path 36.

<Nut inspection device>
The nut inspection apparatus of the present embodiment is an apparatus for inspecting the operational smoothness of the ball screw mechanism caused by the nut 12 mainly by detecting vibration when the bearing ball 14 passes through the communication path 36. . As shown in FIG. 4, the nut inspection device generally has a base 50, a nut carrier 52 provided on the base 50, a shaft-shaped jig 54, four sphere feeding devices 56, and a sphere housing. A bucket 58, a sphere collection box 60, and the like are included.

  The nut carrier 52 is a device that holds the nut 12 to be inspected and moves the nut 12 in the rotation direction and the axial direction (left-right direction in the figure). The nut carrier 52 has a nut holder 70 that holds the nut 12. The nut holder 70 is a chuck device having three chuck claws 72, and the chuck claws 72 hold one end of the nut 12. The nut holder 70 is rotatably supported by a holder support base 74. A nut rotation motor 76 is fixedly disposed on the holder support base 74, and a gear 78 provided on the motor shaft thereof is provided with a nut holder. It is provided on the outer periphery of 70 and meshed with the gear 80. By rotating the motor 76, the nut holder 70, that is, the nut 12 held by the holder 70 is rotated around the axis. Further, two rails 82 are laid on the base 50, and the holder support 74 can be moved in the axial direction by these rails 80. Further, the screw rod 84 is fixedly disposed on the base 50 in a posture extending in the axial direction. The screw rod 84 constitutes a ball screw mechanism and is screwed with a nut (not shown) rotatably provided on the holder support base 74. The holder support base 74 has a structure in which the nut moving motor 86 provided on the holder support base 74 rotates in the axial direction by rotating the nut, whereby the nut 12 held by the nut holder 70 moves in the axial direction. Has been.

  The axial direction position of the nut 12 shown in the figure is a reference position (hereinafter sometimes referred to as “advance reference position”) on which the nut 12 is set with respect to the axial jig 54. The nut 12 can be advanced within a certain range from the reference position for advancement, and further up to a position where the shaft-shaped jig 54 is pulled out from the nut 12 (hereinafter sometimes referred to as “retracted position”). It is possible to retreat. The holder support 74 is provided with a brake 88 that engages with the rail 82, and when the brake 88 is released and no power is supplied to the nut moving motor 86, the shaft jig 54. As the nut 12 is rotated while the nut 12 and the nut 12 are screwed together, the holder support base 74 is allowed to move forward and backward. Incidentally, the nut holder 70 is fitted with a bearing 89 in a state in which the outer race is held, and the tip end portion of the shaft-shaped jig 54 is gently inserted into the inner race at the advancement reference position. Misalignment between the axis of the nut 12 and the shaft-shaped jig 54 is prevented. Further, the rotation position of the nut 12 shown in the figure is a rotation position when the nut 12 is set with respect to the shaft-shaped jig 54 (hereinafter sometimes referred to as “reference rotation position”).

  FIG. 5 shows a front view of the shaft-shaped jig 54, and FIG. 6 shows a BB cross section in FIG. As can be seen from these drawings, a thread groove 90 having a generally cylindrical shape and the same thread groove 16 as that of the above-described screw shaft 10 is partially formed. The position of the nut 12 indicated by a two-dot chain line in the drawing is the advancement reference position, and the four circulation paths 24 described above are formed by the nut 12 and the shaft-shaped jig 54 at that position. In the inspection of the nut 12 by the nut inspection apparatus, the outer shape and material of the bearing ball 14 are the same in the four circulation paths 24, specifically, in a part of the four circulation paths 24 and including the communication path 36. The ball is supplied with an inspection sphere 92 (hereinafter sometimes simply referred to as “sphere 92”), and vibration is detected. Therefore, the shaft-shaped jig 54 is provided with a supply path 96 and a discharge path 98 for the sphere 92 that open to each of the four circulation paths 24. In the shaft jig 54, four supply paths 96 and four discharge paths 98 are provided corresponding to the circulation paths 24, the communication paths 36, and the deflectors 22, respectively. In FIG. 5, only the supply path 96a and the discharge path 98a corresponding to the circulation path 24a are entirely represented by chain lines, and some of the other parts are illustrated with only openings that are visible from the front side. ing. In FIG. 6 as well, only the supply path 96a and the discharge path 98a corresponding to the circulation path 24a are shown in their entirety by broken lines.

  As can be seen from FIGS. 5 and 6, the shaft-shaped jig 54 is solid, and each of the supply passage 96 and the discharge passage 98 is provided by being drilled, and is a portion that extends linearly in the axial direction. And a portion bent from the portion and reaching the screw groove 90. The linearly extending portion is located at a position relatively close to the center in the axial straight section, and the portion reaching the screw groove 90 is bent so as to approach the screw groove 90 in the circumferential direction from the position and screw. Reaching the groove 90, a supply opening 100 and a discharge opening 102 are formed. Since the passage has such a shape, the sphere 92 can be smoothly moved from the supply path 96 to the circulation path 24 and from the circulation path 24 to the discharge path 98. Note that the supply opening 100 of the supply path 96 and the discharge opening 102 of the discharge path 98 corresponding to one circulation path 24 are formed in the thread groove 90 at a position sandwiching the communication path 36, that is, the deflector 22. A cap member 108 provided with four supply pipes 104 and four discharge pipes 106 is attached to the base end portion of the shaft-shaped jig 54. Each of the supply path 96 and the discharge path 98 is provided with the supply pipes. 104 and the discharge pipe 106 are connected to each other. Further, the shaft-shaped jig 54 is fixed to the base 50 by an equal-shaped jig support member 110 (see FIG. 4).

  The spherical body feeding device 56 is a device that supplies the spherical body 92 to the circulation path 24 through the supply pipe 104 and the supply path 96 by the pressure of the compressed air, and corresponds to each of the four circulation paths 24. Four are provided. These four sphere feeding devices 56 have the same structure as each other, and each has a structure as shown in FIG. Each spherical body feeding device 56 has a base block 120 that is a rectangular parallelepiped as a base body, and a main passage 122 and a spherical body introduction passage 124 that are two passages formed in the base block 120 and an upstream provided to open and close the main passage 122. It includes a side valve 126 and a downstream valve 128 and a sphere introduction actuator 130 provided to open and close the sphere introduction path 124. The valves 126 and 128 and the actuator 130 are all electromagnetic.

  A supply pipe 104 is connected to the main passage 122 on the downstream side thereof. Further, on the upstream side, a hose joint 132 to which a hose from a high-pressure air source (not shown) is connected is attached, and compressed air is introduced from the joint 132. Both the upstream valve 126 and the downstream valve 128 communicate with the main passage 122 in the non-excited state and block the main passage 122 in the excited state. The spherical body introduction path 124 has a lower end connected to the main passage 122 between the upstream valve 126 and the downstream valve 128, and the upper end connected to the spherical storage bucket 58 at the other end. It is connected to the introduction pipe 134. The spherical body introducing actuator 130 has a structure in which a stopper 136 whose section is generally J-shaped is advanced and retracted by a solenoid. In the non-excited state shown in the figure, the stopper 136 is retracted, and the locking piece portion below the stopper 136 prevents the plurality of spheres 92 introduced in a row from above from dropping. On the other hand, in the excited state, the stopper 136 is advanced, and the sphere 92 positioned at the lowermost position is dropped into the main passage 122 from the through hole 137 provided in the lower locking piece, and the upper locking piece is used. The other spheres 92 are prevented from falling. Therefore, the sphere introduction actuator functions so that one sphere 92 is introduced into the main passage 122 by its one reciprocal movement. After one sphere 92 is introduced into the main passage 122, both the upstream valve 126 and the downstream valve 128 are opened for a predetermined time, and the sphere 92 is pumped toward the supply pipe 104.

  When feeding a plurality of spheres 92, the above operation, that is, one cycle of operation is repeated. Thereby, the spheres 92 are sequentially supplied to the circulation path 24 formed by the nut 12 and the shaft-shaped jig 54, specifically to the communication path 36, through the supply pipe 104 and the supply path 96 in a state of being connected in a rosary manner. It is possible to do. The main passage 122 is provided with a passage sensor 138 for detecting the passage of the sphere 92, and the sensor 138 can grasp the number of the spheres 92 sent. Incidentally, each spherical body feeding apparatus 56 is supported on the base 50 by the support member 140 (refer FIG. 4).

  The sphere 92 supplied by the sphere feeder 56 is accommodated in the sphere accommodation bucket 58 shown in FIG. One sphere storage bucket 58 is provided in common to the four sphere feeding devices 56, and has four drop openings, each drop opening via each of the four sphere introduction pipes 134, The four sphere supply devices 56 are connected. Note that a saddle 142 is attached to the upper end of the jig support member 110, and two columns 144 are erected on the base 50. A support plate 146 is suspended by the saddle 142 and the two columns 144, and the spherical body storage bucket 58 is supported by the support plate 146.

  On the other hand, a discharge pipe 106 is connected to the discharge path 98 of the shaft-shaped jig 54. The discharge pipe 106 is generally bent downward, and the bent portion is disposed so as to pass between the supply pipes 104 described above and the tip reaches the sphere collection box 60. As shown in FIG. 8, the discharge pipe 106 is provided with a spherical body locking actuator 150. The actuator 150 is an electromagnetic type, and has a structure in which a stopper pin 152 protrudes into the discharge pipe 106 in an excited state. The discharge pipe 106 guides the sphere 92 supplied to the circulation path 24 to the sphere collection box 60. By operating the sphere locking actuator 150, the discharge of the sphere 92 is prohibited, and the sphere 92 is connected in a rosary manner. Some of the plurality of spheres 92 can be retained in the circulation path 24.

  In addition, as shown in FIG. 4, the nut inspection apparatus includes an axial position sensor 160 for recognizing the axial position by detecting the distance to the axial end surface of the nut 12, and the nut 12. A rotational position sensor 162 for detecting the reference rotational position of the nut 12 by detecting the established reference point is provided. The axial position sensor 160 is attached to the jig support member 110 that supports the axial jig 54, and the rotational position sensor 162 is attached to the bracket 164 that extends from the upper part of the jig support member 110. Yes.

  The nut inspection apparatus further includes a control panel 170. The control panel 170 is composed mainly of a computer and drive circuits such as motors and solenoid valves. The front panel is provided with a display 172 as an output device and various operation switches 174 as an input device. ing. The control panel 170 controls the operation of the nut inspection device, and also has a function of analyzing the detected vibration of the nut 12 and determining whether the quality of the nut 12 is good or bad. The chuck claw 72 actuator, the nut rotation motor 76, the nut moving motor 86, the brake 88, the upstream valve 126, the downstream valve 128, the sphere introduction actuator 130, the sphere locking actuator 150, and the like included in the sphere supply device 56, The passage sensor 138, the axial position sensor 160, the rotational position sensor 162 and the like described above are connected to the input port of the control panel 170.

  As shown in FIG. 4, the vibration is detected by attaching an acceleration pick 180, which is a piezoelectric acceleration sensor, as a wave detector to the outer periphery of the nut 12, specifically, in contact with the back surface of the deflector 22. Do. The nut 12 has four deflectors 22, and four acceleration picks 180 are attached, and detection signals from the four acceleration picks 180 are transmitted to the control panel 170. Incidentally, the detection signal of the acceleration pick 180 is amplified by an amplifier provided in the control panel 170, and an analysis process for determining whether the nut 12 is good or not is executed on the amplified signal.

<Nut inspection flow>
In the inspection of the nut 12 using the nut inspection device, first, the nut 12 is set on the shaft-shaped jig 54. Specifically, first, at the position where the holder support base 74 of the nut carrier 52 is retracted (when the nut 12 is held by the nut holder 70, the position of the holder support base 74 located at the retracted position). In the positioned state, the nut 12 to be inspected is pressed against the nut holder 70 and the chuck clamp switch is operated. As a result, the chuck pawl 72 is closed and the nut 12 is held by the nut holder 70. Next, four acceleration picks 180 are attached to the predetermined position of the nut 12, and after the attachment, the inspection start switch is operated. After this operation, the nut inspection device automatically executes a predetermined operation.

  First, based on the detection value of the axial position sensor 160, the holder support 74 is advanced, so that the nut 12 is positioned at the above-mentioned advance reference position, and the brake 88 is operated at that position. Thereafter, the nut 12 is rotated at the advance reference position, and the nut 12 is stopped at the reference rotation position described above based on the detection result of the rotation position sensor 162. By this series of operations, the setting of the nut 12 to the proper position with respect to the shaft-shaped jig 54 is completed.

  Next, the sphere locking actuator 150 provided in each of the four discharge pipes 106 is operated, and the sphere 92 is prohibited from passing through the discharge pipe 106 to the sphere collection box 60. In this state, the four sphere feeding devices 56 start to operate. Specifically, as described above, the operation of one cycle of each of the sphere introduction actuator 130, the upstream valve 126, and the downstream valve 128 is based on the count value obtained from the detection signal of the passage sensor 138. A predetermined number of cycle operations are performed so that a predetermined number of spheres 92 are detained in the circulation path 24 including the communication path 36. That is, a set number of cycle operations are performed so that a predetermined number of spheres 92 are retained in each circulation path 24. By the operation of the sphere supply device 56 as described above, a predetermined number of spheres 92 are supplied into the circulation path 24.

  After the sphere 92 is supplied, an inspection operation is performed. In this inspection operation, first, the brake 88 of the nut carrier 52 is released, and in this state, the nut 12 is reciprocally reversed. Specifically, for example, several reversing operations are performed within a range of ± 180 ° from the reference rotation position. During the reversing operation, analysis processing is performed on the vibration detection signal of each acceleration pick 180. Assume that the vibration detection signals of the four acceleration picks 180a to 180d are, for example, as shown in the graph of FIG. Incidentally, the horizontal axis in FIG. 9 represents the passage of time t, the vertical axis represents the vibration intensity I (corresponding to the amplitude), and each of the detection signals (a) to (d) (hereinafter referred to as “detection”). The signal (a) or the like ”may be a detection signal of the acceleration picks 180a to 180d provided for each of the deflectors 22a to 22d, that is, in each of the communication paths 36a to 36d. This figure shows detection signals at a certain part of the time of the entire inspection operation.

As can be seen from this graph, the vibration detection signal for the nut 12 is a signal having a relatively high strength at a certain time pitch in any of the detection signals (a) to (d). Specifically, those appearing at times t ₁ , t ₁ ′, t ₁ ″ (hereinafter sometimes referred to as “first vibration peak”), and appearing at times t ₂ , t ₂ ′, t ₂ ″. (Hereinafter sometimes referred to as “second vibration peak”). If the first vibration peak is compared, the detection signal (b) has the highest intensity, and if the second vibration peak is compared, the detection signal (c) has the highest intensity. Considering the damping effect in vibration propagation, the first vibration peak is vibration when the sphere 92 passes through the communication path 36b, and the second vibration peak is vibration when the sphere 92 passes through the communication path 36c. Conceivable. Based on this, in this nut inspection apparatus, the vibration occurrence location is specified with the value detected with the highest intensity with respect to the vibration generated at the same time. Then, when the vibration intensity value exceeds the set threshold intensity I ₀ , it is determined that the nut 12 is defective. In the detection signal shown in the graph, the maximum intensity of the first peak exceeds the threshold intensity I ₀ , the nut 12 is recognized as defective, and the communication path 36b is specified as a defective portion. Such a pass / fail judgment result and the specified defective portion are displayed on the display 172 of the control panel 170.

  After the above-described inspection operation is completed, the sphere 92 is unlocked by the sphere locking actuators 150. In the released state, the upstream valve 126 and the downstream valve 128 of each sphere feeding device 56 are set. All the spheres 92 that are opened for a period of time and are present in each of the supply passages 96, the circulation passages 24, the discharge passages 98, etc. are collected in the sphere collection box 60. After such a collecting operation, the nut 12 is moved to the retracted position, and the automatic operation by the nut inspection apparatus is completed. The acceleration pick 180 is removed, the chuck unclamp switch is operated, the nut 12 is removed from the nut holder 70, and the inspection work for one nut 12 is completed.

<Modification>
In the above embodiment, the nut 12 and the shaft-shaped jig 54 are relatively rotated in a state where the plurality of spheres 92 are retained in the circulation path 24, and this is caused by the passage of the sphere 92 through the communication path 36 due to the relative rotation. It was supposed to detect vibration. Instead of such an inspection method, vibration may be detected without performing relative rotation between the nut 12 and the shaft-shaped jig 54. That is, in a state where the nut 12 is placed at the advance reference position and the rotation reference position, the sphere 92 is fed by the sphere feeding device 56 so as to pass through the communication path 36, and vibrations during the passage are detected. It is also possible. At this time, for example, a plurality of spheres 92 may be sequentially passed through the communication path 36 in a state of being connected in a daisy chain, or as if one or several spheres 92 are ejected, You may make it pass the communicating path 36 sequentially.

  Moreover, in the said Example, although it was made to test | inspect using the spherical body 92 of the same shape as the bearing ball 14 in the single-piece | unit state, it is actually the plurality connected in a bead shape as shown in FIG. It is also possible to perform an inspection using the sphere. FIG. 10A shows a structure in which adjacent spheres 200 are connected by a connecting pin 202. The spherical body 200 is provided with recesses 204 at two positions facing away from each other, and at both ends of the connecting pin 202, a generally spherical locked portion 206 is provided. The sphere 200 and the pin 202 are connected by caulking in a state where the stopper 206 is accommodated. The recess 204 has a gap with respect to the locked portion 206, and the spherical body 200 and the connecting pin 202 are allowed to move to a certain extent. FIG. 10B shows a structure in which a sphere 210 is connected by a wire 212. The spherical body 210 is provided with a through hole 214, and the wire 212 passes through the through hole 214. When using the spheres 200 and 210 connected in this way, for example, as shown in FIG. 11, the connected ones are wound around a reel 230 and set, and a portion pulled out from the reel 230 is It is possible to supply the spheres 200 and 210 to the circulation path 24 by sandwiching the rotating drums 232 facing each other and rotating the drums 232. Further, when the spheres 200 and 210 are discharged from the circulation path 24, the spheres 200 and 210 can be wound around the reel 230. In such an embodiment, the inspection sphere can be handled easily.

  Furthermore, in the said Example, it test | inspected using the solid axial jig | tool 54. FIG. Instead of the shaft-shaped jig 54 as described above, a hollow shaft-shaped jig 240 as shown in FIG. 12 can be used. In this case, the jig body 242 is provided with an opening 244 to the circulation path 24, and a pipe 246 bent into a predetermined shape is attached so that one end of the pipe 246 is connected to the opening 244, thereby supplying the sphere. Paths and discharge paths can be formed. That is, the shaft-shaped jig can be configured using a tubular passage forming member.

  Furthermore, in the above-described embodiment, the nut 12 is inspected by detecting vibration when the sphere 92 passes through the communication path 36. Alternatively, the nut 12 can be inspected by detecting sound. In this case, for example, instead of the acceleration pick 180, a microphone as a wave detector is attached to the nut 12, and the quality of the nut is determined, the defective portion is identified based on the sound pressure level detected by the microphone. be able to.

It is sectional drawing which shows typically the ball screw mechanism comprised with the nut used as the test object in the nut test | inspection apparatus of an Example, and the nut test | inspection method using the apparatus. Sectional drawing which expands and shows typically the nut of FIG. 1 is shown. It is the 4th figure and sectional view which show typically the deflator which comprises the nut of FIG. It is a figure which shows the whole structure of the nut test | inspection apparatus of an Example. It is a front view which shows typically the shaft-shaped jig | tool provided in the nut test | inspection apparatus of FIG. FIG. 6 is an axial cross-sectional view of the shaft jig in FIG. 5. It is sectional drawing which shows the spherical body supply apparatus which the nut test | inspection apparatus of FIG. 4 has. It is a figure which shows the spherical discharge pipe which the nut test | inspection apparatus of FIG. 4 has. It is a graph which shows the vibration detection signal obtained by the test | inspection work of a nut. It is a figure which shows the modification of the test | inspection sphere used for a test | inspection of a nut. It is a figure which shows notionally the apparatus for performing supply and discharge | emission of the test | inspection sphere shown in FIG. It is sectional drawing which shows typically the modification of the shaft-shaped jig | tool shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10: Screw shaft 12: Nut 14 Bearing ball 16: Screw groove 18: Screw groove 20: Nut main body 22: Deflector (communication path formation part) 24: Communication path 36: Communication path 52: Nut carrier 54: Shaft-shaped jig 56 : Sphere feeding device 92: Inspection sphere 96: Supply path 98: Discharge path 100: Supply opening 102: Discharge opening 180: Acceleration pick (wave detector) 200: Inspection sphere 210: Inspection sphere 240: Axis treatment Ingredients

Claims (7)

A nut that constitutes a ball screw mechanism in cooperation with a screw shaft and a bearing ball, the nut being formed by a screw groove of the screw shaft and a screw groove of the screw shaft so as to form a circulation path of the bearing ball. An inspection device for inspecting a nut provided with a communication path forming portion for forming a communication path that allows two places to communicate with each other,
A screw groove corresponding to the screw groove of the screw shaft is provided, and is fitted into the nut so as to form the circulation path, and has a supply path provided inside itself and opening to the circulation path. A shaft jig;
One or more spheres corresponding to the bearing balls supplied from the supply path into the circulation path;
A nut inspection device comprising: a wave detector that detects a generated wave that is at least one of sound and vibration generated when the one or more spheres supplied to the circulation path pass through the communication path. The shaft jig is
Provided inside itself, provided with a discharge path for discharging the one or more spheres supplied into the circulation path, opening to the circulation path on the opposite side of the supply path across the communication path The nut inspection device according to claim 1. The nut inspection device
The nut inspection device according to claim 1, further comprising a sphere feeding device that feeds the one or more spheres into the circulation path through the supply path using compressed gas. The nut inspection device
A device for inspecting the nut in which a plurality of circulation paths are formed by providing a plurality of the communication path forming portions, each of the supply paths corresponding to each of the plurality of circulation paths, The nut inspection device according to claim 1, further comprising a plurality of the wave detectors each corresponding to each of the plurality of circulation paths. A nut that constitutes a ball screw mechanism in cooperation with a screw shaft and a bearing ball, the nut being formed by a screw groove of the screw shaft and a screw groove of the screw shaft so as to form a circulation path of the bearing ball. An inspection method for inspecting a nut provided with a communication path forming portion for forming a communication path that allows two places to communicate with each other,
A shaft-shaped jig provided with a thread groove corresponding to the thread groove of the screw shaft and provided with a supply path that opens to the thread groove is formed so that the circulation path is formed and the supply path is the circulation path. A setting step for fitting the nut,
A sphere supply step of supplying one or more spheres corresponding to the bearing balls into the circulation path through the supply path;
And a wave detecting step of detecting a generated wave that is at least one of sound and vibration generated when the one or more spheres supplied to the circulation path pass through the communication path. The wave detection step includes
In a state where the one or more spheres are present in the circulation path, the nut and the shaft-shaped jig are relatively rotated, and the one or more spheres in the circulation path are moved by the relative rotation. The nut inspection method according to claim 5, further comprising a step of detecting the generated wave that is generated. The sphere supply step includes a step of passing each of the one or more spheres through the communication passage while sequentially supplying the spheres into the circulation passage;
The nut inspection method according to claim 5, wherein the wave detection step includes a step of detecting the generated wave every time the one or more spheres pass through the communication path.

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