Patent Description:
A technique is known in which information such as an identification number is retained in each product or part for the purpose of making it possible to trace a process of product production, processing, and distribution to the market and improving quality. For example, <CIT> (Patent Document <NUM>) discloses a bearing engraved with a character string representing a product model number, a date of manufacture, and the like.

In a bearing of Patent Document <NUM>, information such as a model number of a product and a date of manufacture is engraved on a bearing end surface or the like by laser marking. Accordingly, a management of a bearing after shipment is facilitated. For example, even when a bearing is returned from the market due to a defect, information about the bearing can be easily confirmed from the marked information. <CIT> discloses a bearing component according to the preamble of claim <NUM>.

However, in a technique of Patent Literature <NUM>, character string information such as numbers and English characters indicating the model number, date of manufacture, and the like of the product is engraved on an end surface of the bearing. While it is easy to visually check the character string information, there is a disadvantage that reading errors are likely to occur in automatic reading by an optical reading device or the like. Small bearings and thin bearings have a small engraving space, which limits the number of digits that can be recorded in the character string. Therefore, it is difficult to cope with an increase in the amount of information to be recorded and there are many problems to give individual identification information to all bearing components (inner ring, outer ring, and the like) of mass-produced bearings.

An object of the invention is to provide a bearing component, a bearing, a machine, a vehicle, an individual identification method of a bearing component, a bearing manufacturing method, a machine manufacturing method, and a vehicle manufacturing method capable of imparting individual identification information with high reading accuracy and space saving even when the amount of information to be recorded increases.

The invention provides the solution as defined in claims <NUM>, <NUM>-<NUM>, <NUM>-<NUM> and <NUM>.

According to the invention, even when the amount of information to be recorded increases, individual identification information can be provided with high reading accuracy and space saving.

Hereinafter, embodiments of the invention will be described in detail with reference to the drawings. Here, an inner ring and an outer ring of a rolling bearing will be described as an example of a bearing component, but other components such as a holder and a seal member may be used.

<FIG> is a partial cross-sectional perspective view of a rolling bearing. The rolling bearing (hereinafter, simply referred to as "bearing") <NUM> includes an inner ring <NUM>, an outer ring <NUM>, a plurality of rolling elements <NUM> provided between the inner ring <NUM> and the outer ring <NUM>, and a holder <NUM> for rotatably holding the rolling elements <NUM>. The inner ring <NUM> is an annular body which is made of metal such as a steel material and has a raceway groove (guide surface) 11a of the rolling element <NUM> on an outer peripheral surface. The outer ring <NUM> is an annular body which is made of metal such as a steel material and has a raceway groove (guide surface) 13a of the rolling element <NUM> on an inner peripheral surface. A rectangular two-dimensional code M is provided on at least one of an axial end surface 11b of the inner ring <NUM> and an axial end surface 13b of the outer ring <NUM>. <FIG> illustrates a configuration in which the two-dimensional code M is provided on both the inner ring <NUM> and the outer ring <NUM>. The bearing <NUM> may be provided with a seal member (not illustrated).

The two-dimensional code M provided in the inner ring <NUM> includes individual identification information of the inner ring <NUM>. The two-dimensional code M provided in the outer ring <NUM> includes the individual identification information of the outer ring <NUM>. For each individual identification information, various information such as individual information and history information related to each individual, which will be described in detail below, can be extracted by referring to a database prepared in advance.

The two-dimensional code M is preferably stamped on the inner ring <NUM> and the outer ring <NUM> by laser marking. The axial end surfaces 11b and 13b of the inner ring <NUM> and the outer ring <NUM> are easily damaged by being in contact with surrounding members. Therefore, a recessed area may be formed on the axial end surfaces 11b and 13b and the two-dimensional code M may be engraved on the recessed area. As a method for marking a metal surface, there are various known techniques and all of which are applicable. However, especially, it is preferable to apply a laser marking method because laser marking can be formed quickly and accurately.

<FIG> are explanatory views illustrating an example of the two-dimensional code of the invention.

The two-dimensional code M illustrated in <FIG> includes an alignment pattern <NUM> having a pair of line patterns <NUM> and <NUM> orthogonal to each other and a plurality of dots (cells) <NUM>. The long line pattern <NUM> and the short line pattern <NUM> are arranged in a cross shape and the plurality of dots <NUM> are arranged in a grid pattern along the line patterns <NUM> and <NUM>. At each position of the grid pattern, it is either a laser-marked marking point or a non-marked point and the dot <NUM> illustrated in <FIG> indicates the marked marking point. That is, the line pattern <NUM> is a pattern in which all the dots are marked in any of a plurality of dot rows arranged in a longitudinal direction of the two-dimensional code M. The line pattern <NUM> may be a single dot row or a plurality of dot rows. Similarly, the line pattern <NUM> is a pattern in which all dots are marked in any of a plurality of dot rows arranged in a direction orthogonal to the longitudinal direction of the two-dimensional code M.

The two-dimensional code M illustrated in <FIG> includes the alignment pattern <NUM> having a pair of line patterns <NUM> and <NUM> which are L-shaped and orthogonal to each other and the plurality of dots (cells) <NUM>. Here, the line pattern <NUM> is a pattern in which all the dots are marked in an outermost (lower end of <FIG>) row of the plurality of dot rows arranged in the longitudinal direction of the two-dimensional code M. The line pattern <NUM> is a pattern in which all dots are marked in an outermost (left end of <FIG>) row of the plurality of dot rows arranged in the direction orthogonal to the longitudinal direction of the two-dimensional code M.

The two-dimensional code M illustrated in <FIG> is a fan-shaped two-dimensional code M. In the two-dimensional code M, the line pattern <NUM> is arranged along a circumferential direction and the line pattern <NUM> is arranged along a radial direction. The fan-shaped two-dimensional code M has an arc shape on the inner peripheral side and the outer peripheral side, respectively, and a linear shape along the radial end on the peripheral end side. The plurality of dots <NUM> are arranged along the radial direction and the circumferential direction. The line patterns <NUM> and <NUM> of <FIG> have cross-shaped intersections with each other and the line patterns <NUM> and <NUM> of <FIG> are arranged so that the intersections of the line patterns <NUM> and <NUM> of <FIG> are L-shaped.

The two-dimensional code M may be trapezoidal, convex, or the like in addition to the above-described rectangular shape and fan shape and may have a shape in which the maximum dimension in the circumferential direction of the bearing is longer than the maximum dimension in the radial direction.

<FIG> is an explanatory view schematically illustrating an arrangement example of the two-dimensional code M engraved on the axial end surface of the inner ring <NUM> and the outer ring <NUM>.

The two-dimensional code M engraved on the inner ring <NUM> and the outer ring <NUM> has a shape in which a maximum circumferential dimension Lw is longer than a maximum radial dimension Lh. Here, φR indicates an outer diameter and φr indicates an inner diameter. An extension direction of the long line pattern <NUM> is orthogonal to the radial direction of the annular inner ring <NUM> and the annular outer ring <NUM> at a center of the line pattern <NUM> in the longitudinal direction. That is, the line pattern <NUM> is generally arranged to coincide with a tangential direction T of the annular inner ring <NUM> and the annular outer ring <NUM> at the marking position of the two-dimensional code M. The term "coincide" as used herein means that the angle falls within a range of ± <NUM>°, preferably ± <NUM>°.

As described above, by engraving the two-dimensional code M on the axial end surfaces 11b and 13b of the inner ring <NUM> and the outer ring <NUM>, respectively, individual identification information can be given to each of the inner ring <NUM> and the outer ring <NUM>. In general, the two-dimensional code is not visually readable like character string information, so one cell can be arranged in a small size (code size: <NUM> × <NUM>, <NUM> × <NUM>, or the like. ) of about <NUM> to <NUM>. Accordingly, since the size of the two-dimensional code M is small, space-saving arrangement is possible even in a limited small space, and thus the degree of freedom in the arrangement of the two-dimensional code is increased.

On the other hand, in one-dimensional codes such as character string information and barcodes, the information itself becomes unreadable when a part of the code is missing due to scratches or the like. However, in the two-dimensional code, information can be read even when a part of the code is missing. Therefore, even when the inner ring <NUM> or the outer ring <NUM> is used in an environment where the rings are easily scratched, the individual identification information can be reliably added without affecting the readability by using the two-dimensional code M.

Next, a specific example of product management using the two-dimensional code M will be described.

<FIG> is a process explanatory diagram schematically illustrating a part of processes in a rolling bearing production line.

A pre-shipment production and control process of the bearing <NUM> includes a grinding process GR, an assembly process AS, and an inspection process IS.

In the grinding process GR, an annular product material (workpiece) to be the inner ring <NUM> or the outer ring <NUM> is subjected to a grinding process for forming the raceway groove 11a or 13a illustrated in <FIG>, in such a manner that the inner ring <NUM> and the outer ring <NUM> are manufactured. The workpiece is supplied to the grinding process GR in a state where the axial end surface and the outer peripheral surface or inner peripheral surface are ground.

In the assembly process AS, the bearing <NUM> including the inner ring <NUM>, the outer ring <NUM>, the rolling element <NUM>, and the holder <NUM> is assembled. In the inspection process IS, the assembled bearing <NUM> is inspected.

In a previous stage of the grinding process GR described above, a marking process S1 for engraving the two-dimensional code M representing the individual identification information (ID) unique to the workpiece and a reading and registration process S2 for reading the engraved marking and registering the read ID in the database are performed.

In the marking process S1, the two-dimensional code M representing an ID corresponding to the workpiece is stamped on a product material with respect to the workpiece transported to the production line. A marking position is not particularly limited, but is, for example, axial end surfaces 11b and 13b as illustrated in <FIG>. The ID of the two-dimensional code M to be engraved is created according to a prescribed rule and may be set according to various conditions such as the date and time of processing, the material, the lot number, and the heat treatment, or may be a serial number.

In the reading and registration process S2, the workpiece on which the two-dimensional code M is stamped in the marking process S1 is set in a reading device <NUM> (see <FIG>) described below and the stamped two-dimensional code M is read. Then, the ID read from the two-dimensional code M is registered in a database DB. Here, the management information of each workpiece which is a bearing component is registered in the database DB in association with the read ID.

The workpiece for which the reading and registration process S2 for the two-dimensional code M is completed is transported to a reading unit R1 for the two-dimensional code, which is a previous stage of the grinding process GR.

The reading unit R1 (the same applies to reading units R2 and R3 below) also includes a reading device <NUM> (see <FIG>) described below. The reading unit R1 sets the transported workpiece in the reading device <NUM> and reads the two-dimensional code M engraved on the workpiece. Then, with reference to the information in the database DB corresponding to the read ID, it is determined (verified) whether the workpiece of that ID is a workpiece which may be subjected to the next process (machining, assembly, inspection).

As a result of verification, when the workpiece is a workpiece which can be subjected to the next process, the workpiece is transported to the grinding process GR. On the other hand, when the workpiece is a defective workpiece or when an abnormality occurs in equipment and the workpiece cannot be advanced to the next process, the workpiece is discharged from the production line as a "discharge workpiece".

In the grinding process GR, the raceway surfaces are formed on the transported workpieces, and thus the workpieces are processed into the inner ring <NUM> and the outer ring <NUM> shown in FIG. Then, processing information in the grinding process GR is registered in the database DB in association with the ID read by the reading unit R1. The processing information includes various kinds of information such as a grinding machine, a tool, and a machining condition used in the grinding process GR. The processed workpiece (inner ring <NUM> or outer ring <NUM>) is transported to the reading unit R2, which is a previous stage of the assembly process AS.

The reading unit R2 reads the two-dimensional code M stamped on the workpiece and refers to the information in the database DB corresponding to the read ID, similarly to the reading unit R1 described above. When the workpiece with that ID is a workpiece which may be subjected to the next process, the workpiece is transported to the assembly process AS, and when the workpiece cannot be advanced to the next process, the workpiece is discharged from the production line as a "discharge workpiece". When the workpiece is discharged, the discharge information is recorded in the database DB in association with the ID of the workpiece.

Discharge information contributes to surely preventing the workpiece from flowing out to a subsequent process even when the workpiece once discharged is re-input to the production line due to human error or distinguishing a target workpiece from discharged workpieces when it is necessary to investigate the contents of NG.

In the assembly process AS, in addition to the workpiece (one of inner ring and outer ring) transported from reading unit R2, another workpiece (the other of inner ring and outer ring) corresponding to the workpiece, the rolling element <NUM>, and the holder <NUM> illustrated in <FIG> are prepared. That is, in the assembly process AS, various bearing components including the inner ring <NUM>, the outer ring <NUM>, the rolling element <NUM>, and the holder <NUM> which forms the rolling bearing are prepared and the bearing <NUM> is assembled using the various bearing components.

Here, the workpiece is engraved with the two-dimensional code M corresponding to the above-described ID and the ID is registered in the database DB. However, other bearing components (rolling element <NUM>, holder <NUM>, seal member (not illustrated), and the like) may also be provided with a code by engraving a two-dimensional code or the like and managed in the database DB together with the ID of the workpiece. The two-dimensional code M can be engraved on a shaft end surface of a roller when the rolling element is a roller.

Then, the bearing <NUM> assembled in the assembly process AS is associated with the ID read by the reading unit R2 and the assembly information in the assembly process AS is registered in the database DB. The assembly information includes various kinds of information such as information on the combination of the inner ring <NUM> and the outer ring <NUM>, information on the lot number of the bearing <NUM>, and information on other bearing components.

Next, the bearing <NUM> after the assembly process AS is transported to the reading unit R3, which is a pervious stage of the inspection process IS.

In the reading unit R3, the two-dimensional code M stamped on the workpiece is read in the same manner as the reading units R1 and R2 described above, and then the database DB is referred to by using the read ID. When the workpiece with the ID is a workpiece which may be subjected to the next process, the workpiece is transported to the inspection process IS, and when the workpiece cannot be advanced to the next process, the workpiece is discharged from the production line. When the workpiece is discharged, discharge information is recorded in the database DB in association with the ID of the workpiece.

In the inspection process IS, a predetermined inspection is performed on the workpiece. Then, the inspection result is associated with the ID read by the reading unit R3 and registered in the database DB. The inspection information includes information such as appearance, presence of abnormal noise, inspection results obtained by performing such as sealing property, and the like. Inspection information is also associated with the ID of the workpiece in the ID of each of the other bearing components assembled together with the workpiece.

Then, the bearing <NUM> is shipped as a product through pre-shipment processes such as packing and storage.

As described above, the ID is read from the two-dimensional code M stamped on the product material each time the workpiece of the product material passes through each of the processes of the grinding process GR, the assembly process AS, and the inspection process IS. Then, it is verified with the database DB whether the subsequent process can be carried out on the work. Process information such as processing information, assembly information, and inspection information is associated with the read ID and registered in the database DB.

As a result, it is possible to prevent unnecessary processing from being performed. Even when a problem occurs in the bearing after the product is shipped, corresponding management information can be easily extracted from the database DB based on the ID of the inner ring or the outer ring of the bearing. Therefore, history information such as which tool of which machine the defective bearing is machined and which part is combined with the bearing can be tracked, which can contribute to the improvement of production quality.

The two-dimensional code M is assigned to all of the product materials and the two-dimensional code M of the workpiece is read before and after each process of the grinding process GR, the assembly process AS, and the inspection process IS. For example, the workpiece (bearing <NUM>, inner ring <NUM>, outer ring <NUM>) is extracted from the production line, and then when the workpiece is re-input to the production line with the reading unit R2 or the like, illustrated in <FIG>, the re-input workpiece has different specifications such as lots and processing conditions from the workpieces before and after the line. Although, since the two-dimensional code M is assigned to all the workpieces, the history information of the individual can be traced regardless of the manufacturing order. In other words, the history of each process of bearing components for which independent IDs are assigned to all individuals is associated with that ID and registered in the database, so that quality control of all products can be performed reliably for each part.

Next, a reading device which reads the two-dimensional code described above will be described.

<FIG> is a schematic configuration diagram illustrating an example of the reading device <NUM> used in the reading units R1 to R3 of <FIG>.

The reading device <NUM> includes a workpiece rotation drive unit <NUM> which rotates while holding the workpiece W (it may be the inner ring <NUM>, the outer ring <NUM>, or the bearing <NUM>), two imaging optical systems <NUM> and <NUM>, and a control unit <NUM> which controls the imaging optical systems <NUM> and <NUM>.

The workpiece rotation drive unit <NUM> includes a rotating shaft <NUM> extending in an up-down direction, a workpiece mounting table <NUM> having a disk-shape and fixed to an upper end portion of the rotating shaft <NUM>, and a drive unit (not illustrated) which rotationally drives the rotating shaft <NUM>. The workpiece mounting table <NUM> includes a positioning frame <NUM> which is provided to project upward from an upper surface of the mounting table and holds an outer peripheral surface of the workpiece W coaxially with the rotating shaft <NUM>. The positioning frame <NUM> prevents the workpiece W from being displaced when the workpiece mounting table <NUM> is rotated. The positioning frame <NUM> may hold an inner peripheral surface of the workpiece W and may be omitted depending on the size of the workpiece W, rotation conditions, and the like.

Each of the pair of imaging optical systems <NUM> and <NUM> includes a light irradiation unit <NUM> which irradiates an axial end surface Ws (axial end surfaces 11b and 13b in <FIG>) of a workpiece W with an illumination light ray L, an imaging unit <NUM> which receives a reflected light ray from the axial end surface Ws and images a predetermined region, and a recognition processing unit <NUM> which performs arithmetic processing on the captured image.

The imaging optical system <NUM> images one circumferential position in the axial end surface Ws of the workpiece W and the imaging optical system <NUM> images the axial end surface Ws in the other circumferential position which is separated from one circumferential position by <NUM>° at a central angle. That is, the imaging optical systems <NUM> and <NUM> simultaneously image both ends in a radial direction of the axial end surface Ws of the workpiece W, that is, point-symmetrical positions separated by <NUM>° in the circumferential direction.

A control unit <NUM> controls the drive of the workpiece rotation drive unit <NUM> and the like according to the output of respective recognition processing units <NUM> of the imaging optical systems <NUM> and <NUM>.

In the reading device <NUM> configured as described above, the workpiece rotation drive unit <NUM> rotates the workpiece W at a predetermined rotation speed. Then, each of the two imaging optical systems <NUM> and <NUM> continuously images the axial end surface Ws of the rotating workpiece W at a predetermined frame rate (for example, <NUM> to <NUM> frame / sec).

Here, since imaging is performed using two imaging optical systems <NUM> and <NUM> at the same time, at least a part of the two-dimensional code M is reflected in the captured image only by rotating the workpiece W by at least <NUM>°. Therefore, the engraved position of the two-dimensional code M can be detected faster than the case of searching with only one imaging optical system. The size (field of view size) of the imaging region is adjusted to a size corresponding to the rotation speed of the workpiece W and the imaging ability of the imaging optical systems <NUM> and <NUM>.

The imaging optical systems <NUM> and <NUM> output continuously captured images to the respective recognition processing units <NUM>. In the recognition processing unit <NUM>, the captured image in which the entire two-dimensional code M is contained in the imaging region is selected from the input imaging data, and then the two-dimensional code M is read from the selected captured image. The reading device <NUM> illustrated in <FIG> includes two imaging optical systems <NUM> and <NUM>, but the number of imaging optical systems may be three or more.

<FIG> are explanatory views illustrating a procedure from reading the imaging data to performing the code recognition process for reading the two-dimensional code information.

The recognition processing unit <NUM> continuously images the rotating workpiece W. For example, one round of the workpiece W is imaged with, for example, ten captured images so that a part of the imaging region overlaps. The captured images in the case of the present setting are roughly classified into a captured image of an imaging region IMG1 illustrated in <FIG> in which the two-dimensional code M is not reflected in the captured image, a captured image of an imaging region IMG2 illustrated in <FIG> in which a part of the two-dimensional code M is projected on the imaging region, and a captured image of an imaging region IMG3 in which the entire two-dimensional code M illustrated in <FIG> is projected in the imaging region.

From the images, the captured image of the imaging region IMG3 is selectively extracted and a recognition process for the two-dimensional code M is performed using the captured image of the imaging region IMG3. The extraction process of the captured image can be performed, for example, by performing appropriate image processing on the captured images of a large number of captured data and extracting the image and selecting a specific captured image according to a relationship between a frame rate of the captured data, the rotation speed of the workpiece W, and the like. When the captured image illustrated in the imaging region IMG3 is obtained during imaging, the subsequent imaging may be stopped. Here, the reading time of the imaging data can be shortened and the tact can be improved. By predicting an imaging time of the specific captured image described above and imaging it at the predicted time, a captured image in which the entire two-dimensional code M is projected may be obtained.

It is preferable that, as illustrated in the image of the imaging region IMG3 illustrated in <FIG>, the two-dimensional code M be arranged in a center of the imaging region IMG3 and the longitudinal direction of the two-dimensional code M coincide with an arrangement direction of imaging pixels in order to easily carry out the recognition process. Therefore, the two-dimensional code M is placed on the workpiece W in a state of making an extension direction of the line pattern <NUM> of the two-dimensional code M orthogonal to a radial direction r of the annular workpiece W, that is, setting a direction which coincides with a tangential direction T at the engraved position of the two-dimensional code M.

<FIG> is a schematic explanatory view illustrating how the two-dimensional code is inclined.

An angle θ formed by the extension direction of the line pattern <NUM> of the two-dimensional code M and a horizontal direction (horizontal pixel arrangement direction of image elements) of the captured image is preferably in a range of ± <NUM>° to ± <NUM>°. That is, the closer θ is to a multiple (<NUM>°, <NUM>°, <NUM>°) of <NUM>°, the longer the reading processing time (calculation time) of the two-dimensional code, or the more difficult it becomes to read accurately. Therefore, it is preferable that the radial line passing through the center of the circle of the annular workpiece W be orthogonal to the horizontal direction of the captured image and the image be taken with reference to a circumferential angle of <NUM>° and <NUM>° in a plan view of the workpiece W. It is preferable to minimize the circumferential width of the imaging region (the length in the longitudinal direction of the two-dimensional code) because unnecessary calculations can be omitted.

When the extension direction of the line pattern <NUM> does not match the tangential direction T of the annular workpiece W, that is, when the extension direction is inclined from the tangential direction T, as the workpiece W rotates, the line pattern <NUM> tends to protrude from the imaging region. Here, it is necessary to lower imaging magnification in order to project the entire two-dimensional code M, and thus the detection accuracy is lowered.

Therefore, by keeping the direction (angle θ) of the two-dimensional code M within the range described above, even when the imaging region IMG is narrowed (see, for example, an imaging region IMGs indicated by the alternate long and short dash line), the entire code can be easily included in the imaging region IMG. Since the correction for the code inclination at the time of reading the information of the two-dimensional code M can be reduced, the calculation processing time can be shortened and the reading speed can be improved. Since each cell of the two-dimensional code M can be read efficiently and accurately, the reading accuracy of the code content is improved. The effects of shortening the processing time and improving the reading accuracy described above become more remarkable as the number of images taken increases and the imaging region becomes wider.

The length of the imaging region IMG illustrated in <FIG> in a vertical direction greatly affects the image processing time. Therefore, by narrowing an allowable range of variation in the position of the two-dimensional code in the vertical direction, it is not necessary to process extra figures other than the code, and thus it is possible to read the two-dimensional code at high speed and reliably.

When the long line pattern <NUM> is present in the captured image along the tangential direction T of the annular workpiece W, it becomes easy to detect a circumferential position of the two-dimensional code M even when the workpiece W is rotated at high speed. Therefore, as described above, the two-dimensional code M preferably has a shape in which a maximum dimension in the circumferential direction is longer than a maximum dimension in the radial direction of the bearing, such as a horizontally long rectangle or a fan shape along the circumferential direction. As a result, the detection accuracy can be improved as compared with the case where the two-dimensional coat is square. The smaller the two-dimensional code M is, the more likely it is that the two-dimensional code is overlooked in the rotary reading. In such a case, a two-dimensional code reading method according to the configuration becomes particularly useful.

Since details of a recognition process for reading the information of the two-dimensional code M are known techniques, the description thereof will be omitted here.

The above-described method of detecting the position (phase) of the two-dimensional code M and the method of acquiring a captured image for reading the code are examples, and are not limited thereto. For example, the method may be a two-step reading method in which the arrangement position of the two-dimensional code of the workpiece W is first detected from the captured image, and then the detected arrangement position is magnified and imaged to read the two-dimensional code.

That is, the method of reading the two-dimensional code by the reading device of the configuration has following steps (<NUM>) to (<NUM>).

The image captured in the first step described above is an image obtained by capturing the entire workpiece W and the image captured in the third step is an image obtained by enlarging or capturing a part of the workpiece W with high resolution.

Table <NUM> shows a method of detecting the position (phase) of the two-dimensional code M and Table <NUM> shows a method of acquiring an image for reading the two-dimensional code M.

As illustrated in Table <NUM>, it may be a method (A1) in which the position of the two-dimensional code M is detected by imaging the entire other part of the workpiece W with one imaging optical system. Here, the structure of the reading device can be simplified.

As described above, in addition to the method (A2, A3) of imaging the workpiece W rotationally driven by a single or a plurality of imaging optical systems, it may be a method (A4, A5) of imaging the workpiece W while moving a single or a plurality of imaging optical systems. It may be a method (A6) in which a plurality of imaging systems for imaging different regions are prepared in advance and an output signal from the imaging optical system where the two-dimensional code of the workpiece W is included in the imaging region is selectively switched and used.

<FIG> are explanatory views illustrating a method for detecting the position (phase) of the two-dimensional code.

As illustrated in <FIG>, the entire workpiece W may be imaged by a single imaging optical system and the position of the two-dimensional code M may be detected from the obtained captured image (A1). The arrangement position of the two-dimensional code M is represented as the position in the circumferential direction in the workpiece W by using, for example, the coordinates x and y and an inclined angle φ between an image horizontal direction (X direction) and an orthogonal direction of the line pattern <NUM> (see <FIG>).

As illustrated in <FIG>, with the workpiece W stationary, a single imaging optical system may be moved to acquire captured images of imaging regions IMG_a to IMG_d at each destination position, and then the position of the two-dimensional code M may be detected from the captured image of the imaging region IMG_d including the two-dimensional code M (A4). In <FIG>, the imaging region IMG_a is shown by hatching. It is preferred that the imaging regions overlap each other. Here, when images are taken simultaneously using a plurality of imaging optical systems, the number of times of imaging can be reduced and the image acquisition time can be shortened (A5).

As illustrated in <FIG>, with the workpiece W stationary, a plurality of imaging optical systems may be fixed in advance to image a plurality of different locations in the circumferential direction of the workpiece W and captured images of different imaging regions IMG_A to IMG_D may be acquired by the plurality of imaging optical systems (A6). Here, the image acquisition time can be shortened by simultaneously imaging with the plurality of imaging optical systems. In <FIG>, the imaging region IMG_A is shown by hatching.

Examples of the process of re-imaging the detected position of the two-dimensional code and acquiring the image data for reading the two-dimensional code include the methods (B <NUM>) to (B3) shown in Table <NUM>.

<FIG> are explanatory views illustrating a method for acquiring an image for reading the two-dimensional code.

As illustrated in <FIG>, the workpiece W may be rotated so that the detected two-dimensional code M fits in the imaging region IMG of one imaging optical system fixed at a predetermined fixed position and the two-dimensional code M located within the imaging region IMG may be imaged (B <NUM>).

As illustrated in <FIG>, by using one imaging optical system which can move within a placement plane of the stationary workpiece W, the imaging optical system may be moved and perform imaging so that the two-dimensional code M of the workpiece W fits within the imaging region IMG of the imaging optical system (B2). Here, the imaging optical system can move toward the two-dimensional code M in a shortest distance, and thus the imaging time can be shortened. Since the imaging optical system can be moved freely, the orientation of the imaging can be easily adjusted, and thus the horizontal direction of the captured image can be easily matched with the longitudinal direction of the line pattern of the two-dimensional code M.

As illustrated in of <FIG>, the entire workpiece W may be imaged to read the two-dimensional code M (B3). Here, it is desirable to take an image with a high resolution which does not affect the reading accuracy of the code information according to the size of the two-dimensional code M.

The above-described methods (A1 to A6) for detecting the position (phase)of the two-dimensional code and the methods (B <NUM> to B3) for acquiring the image for reading the two-dimensional code can be appropriately combined and the optimum combination can be selected according to various conditions such as the size of the workpiece W and the space of the reading device.

When the imaging optical system is configured to have an increased imaging resolution, the two-dimensional code information can be directly read from the high-resolution captured image obtained by capturing the entire workpiece W. Here, it is not necessary to move the workpiece W or the imaging optical system, and thus the structure of the reading device can be greatly simplified.

The method for reading the two-dimensional code omits the step (<NUM>) of detecting the circumferential position of the two-dimensional code in (<NUM>) to (<NUM>) described above, and thus it is also possible to more easily read the two-dimensional code.

That is, a simpler reading method (B4) of the two-dimensional code includes,.

According to the method for reading the two-dimensional code, the bearing component can be easily identified by reading the two-dimensional code of the bearing component.

Here, as described above, the bearing component is rotated or the imaging optical system is moved to extract the captured image in which the two-dimensional code is captured from the obtained captured image group and the two-dimensional code can be read from the extracted captured image. When the two-dimensional code is included in the captured image obtained by sequentially capturing a plurality of locations of the bearing component in real time and the information of the two-dimensional code is read from the captured image, the imaging of the captured image after the imaging location is stopped. Therefore, useless imaging can be omitted, and thus the tact time for two-dimensional code detection can be shortened.

A plurality of imaging optical systems may be fixed in advance to image a plurality of different locations in the circumferential direction of the workpiece W, and then captured images of different imaging regions may be acquired by the plurality of imaging optical systems. Here, the image acquisition time can be shortened by simultaneously imaging with the plurality of imaging optical systems. When the information of the two-dimensional code is read from the image captured by at least one imaging optical system among the plurality of imaging optical systems, the reading process of the captured image by the imaging optical system other than the imaging optical system is stopped. Therefore, unnecessary reading process can be omitted, and thus the calculation load for reading can be reduced. Therefore, the tact time of two-dimensional code detection can be shortened.

The above-described two-dimensional code reading method B4 is an example and it is also possible to appropriately combine the above-described steps A1 to A6 and B1 to B3.

Next, another configuration example of the reading device <NUM> will be described.

<FIG> are schematic cross-sectional views of a main part illustrating another configuration example of the workpiece rotation drive unit included in the reading device <NUM>.

The workpiece rotation drive unit <NUM> having the configuration includes a workpiece mounting table <NUM> on which the workpiece W is placed and a rotation support body <NUM> which supports and rotates the workpiece W.

The workpiece W shown here is the rolling bearing <NUM> including the inner ring <NUM>, the outer ring <NUM>, and the rolling element <NUM>.

A circular through hole 51a is formed in the workpiece mounting table <NUM>. The rotation support body <NUM> is arranged coaxially with the through hole 51a and is connected to a rotation drive mechanism (not illustrated) to be able to rotate and ascend and descend. The rotation support body <NUM> includes a shaft portion 53a, a flange portion 53b protruding radially outward on a base end side (lower side) of the shaft portion 53a, and an inclined guide portion 53c formed at the tip of the shaft portion.

In a state where the rotation support body <NUM> is retracted downward as illustrated in <FIG>, an end surface of the outer ring <NUM> is placed on a peripheral edge of the through hole 51a of the workpiece mounting table <NUM> and the rolling bearing <NUM> is supported by the workpiece mounting table <NUM>.

Then, as illustrated in <FIG>, the rotation support body <NUM> is raised while being rotationally driven. Then, the shaft portion 53a of the rotation support body <NUM> is inserted into an inner peripheral surface of the inner ring <NUM> of the bearing <NUM> placed on the workpiece mounting table <NUM> while being guided by the inclined guide portion 53c. When the shaft portion 53a of the rotation support body <NUM> is inserted into the inner ring <NUM>, an upper surface of the flange portion 53b abuts on the end surface of the inner ring <NUM>, and the flange portion 53b lifts the inner ring <NUM>, the outer ring <NUM> emerges from the workpiece mounting table <NUM>. Here, the rolling bearing <NUM> is supported while being rotationally driven by the rotation support body <NUM>.

According to the workpiece rotation drive unit <NUM> having the above configuration, the shaft portion 53a of the rotation support body <NUM> can be positioned with high accuracy on an axis of the inner ring <NUM>, and thus the rolling bearing <NUM> can be rotationally driven without being eccentric.

In order to prevent slippage and misalignment of a workpiece such as the rolling bearing <NUM>, it is preferable that the workpiece rotation drive unit <NUM> uses a resin material, a metal material, or a combination thereof that is compatible with the workpiece, has swelling property, or the like. It is more preferable that the surface of the workpiece rotation drive unit <NUM> be subjected to surface treatment such as roughening. Especially at the time of imaging, it is preferable to finish in a matte black color to prevent reflections other than the workpiece. By roughening the surface or providing at least fine grooves extending in the radial direction, the coefficient of friction with the workpiece can be increased, and thus a film of liquid such as oil adhering to the workpiece can be escaped.

The case where the two-dimensional code M to be read by the reading device <NUM> described above is provided in only one place of the workpiece W, that is, the axial end surface 11b of the inner ring <NUM> or the axial end surface 13b of the outer ring <NUM> is described. However, the number of two-dimensional codes M is not limited to one. When the marking time on the production line is acceptable, the two-dimensional code M may be provided at a plurality of locations in the circumferential direction of the workpiece W. When the two-dimensional code M is provided at a plurality of locations, it is preferable to arrange the codes at equal intervals in the circumferential direction of the workpiece W. When the two-dimensional code M is provided at two locations at equal intervals in the circumferential direction of the workpiece W, it is equivalent to a state in which only one of the imaging optical systems <NUM> and <NUM> illustrated in <FIG> is activated. Therefore, here, the reading device <NUM> can be configured with only one imaging optical system, and thus the equipment cost can be reduced. When the two-dimensional code M is provided at a plurality of locations of the workpiece W and a plurality of imaging optical systems are used, the detection process of the two-dimensional code M can be made faster. As a result, the tact time can be shortened.

As illustrated in <FIG>, the two-dimensional code M may be provided on an outer peripheral surface 13c of the outer ring <NUM>. When the two-dimensional code M is provided on the axial end surface 11b of the inner ring <NUM> or the axial end surface 13b of the outer ring <NUM>, the axial end surfaces 11b and 13b may be rubbed depending on the manufacturing process. However, by providing the two-dimensional code M on the outer peripheral surface 13c of the outer ring <NUM>, damage to the two-dimensional code in the manufacturing process can be prevented. The two-dimensional code M may be provided on an inner peripheral surface 11c of the inner ring <NUM>. Accordingly, when the two-dimensional code M is provided on the outer peripheral surface 13c and the inner peripheral surface 11c, the arrangement space of the two-dimensional code M is wider than the case of the axial end surfaces 11b and 13b. Therefore, it is possible to increase the size of the two-dimensional code M. Here, the arrangement position of the two-dimensional code M becomes easy to see. Therefore, for example, when there is work to read the two-dimensional code at the time of product shipment, the work can be reduced. Even when the two-dimensional code M is provided on the outer peripheral surface 13c and the inner peripheral surface 11c, the probability of missing the two-dimensional code during the above-described rotational reading can be reduced.

A small and shallow two-dimensional code formed on the shaft end surface of the bearing may be used in the production of the bearing and a two-dimensional code may be given to the outer peripheral surface of the bearing at the time of shipment of the bearing. Here, the outer peripheral surface of the bearing has little effect on quality, so large and deep marking is possible. It is also possible to read the two-dimensional code M after bearing has been used on the market. The shape of the two-dimensional code provided on the outer peripheral surface of the bearing is preferably a shape in which the maximum dimension in the circumferential direction is longer than the maximum dimension in the axial direction of the bearing.

The bearing described above can be applied to, for example, bearings 100A and 100B which support the rotating shaft <NUM> of a motor <NUM> illustrated in <FIG>.

The motor <NUM> is a brushless motor and includes a center housing <NUM> having a cylindrical shape and a front housing <NUM> which has a substantially disk shape and closes one opening end of the center housing <NUM>. Inside the center housing <NUM>, a rotatable rotating shaft <NUM> is supported along an axis thereof via the bearings 100A and 100B arranged at the bottom of the front housing <NUM> and the center housing <NUM>. A rotor <NUM> for driving a motor is provided around the rotating shaft <NUM> and a stator <NUM> is fixed to an inner peripheral surface of the center housing <NUM>.

The motor <NUM> having the above configuration is generally mounted on a machine or a vehicle and rotationally drives the rotating shaft <NUM> supported by the bearings 100A and 100B.

As an application example of the bearing, a machine with a rotating part, various manufacturing equipment, for example, a screw device such as a ball screw device, and a rotary support portion of a linear motion device such as an actuator (combination of linear motion guide bearing and ball screw, XY table, and the like), and a steering column, a universal joint, an intermediate gear, a rack and pinion, an electric power steering device, and further a rotation support portion of a steering device such as a worm reducer, and still further a rotation support portion of a vehicle such as an automobile, a motorcycle, and a railroad can be exemplified. Bearings of the configuration can be suitably applied to locations which rotate relative to each other, which can lead to improvement in product quality.

The invention is defined by the scope of the appended claims.

For example, in the embodiment described above, a rolling bearing is described as an example, but the invention can be suitably applied to other types of bearings such as a sliding bearing.

The arrangement position of the two-dimensional code is not limited to the axial end surface, the inner peripheral surface, and the outer peripheral surface of the bearing, and when there is another surface such as a chamfer portion which can be easily detected, the code can be placed on that surface.

When the bearing component is provided with both the two-dimensional code and the character marking, the code and the character marking may be provided at positions where the code and the character marking do not overlap each other. When the two-dimensional code is provided on one of the axial end surfaces of the bearing component, the character marking may be provided on the other axial end surface and the other axial end surface may be used as a sliding surface for transportation on the production line.

The bearing component makes it easier to read the two-dimensional code. For example, it is easy to assign the individual identification information to all bearing components mass-produced with the two-dimensional code and manage each bearing component individually.

By detecting the position and orientation of the two-dimensional code based on the line pattern, the two-dimensional code can be reliably detected and the code content can be read accurately.

An extension direction of the line pattern can coincide with a tangential direction of a circumference of the annular member.

Accordingly, when the bearing component is rotated around an axis, the line pattern continues to be placed at a specific radial position of the bearing component. As a result, it becomes easier to detect the two-dimensional code.

The two-dimensional code can be located on an axial end surface of the bearing component.

Accordingly, by providing the two-dimensional code on one axial end surface and bringing the other axial end surface into contact with a mounting surface, stable two-dimensional code imaging is possible. As a result, it is possible to improve the detection and recognition accuracy of the two-dimensional code.

The two-dimensional code can be located on an outer peripheral surface of the bearing component.

Accordingly, a placement space can be increased compared to the case where the two-dimensional code is provided on the axial end surface. As a result, larger two-dimensional codes can be provided.

The two-dimensional code can be provided at a plurality of locations along a circumferential direction of the annular member.

Accordingly, the two-dimensional code can be easily detected as compared with the case where only one two-dimensional code is provided in the circumferential direction. As a result, the tact can be improved.

The two-dimensional code can be a laser marking engraved on a metal surface. Accordingly, the two-dimensional code can be marked with high accuracy in a short time.

The bearing component can be an outer ring or an inner ring of a rolling bearing.

Accordingly, the individual identification information can be given to the outer ring or the inner ring, and thus the outer ring and the inner ring can be managed individually.

According to the bearing, the machine, and the vehicle, quality control can be facilitated by giving the individual identification information to the bearing component.

According to the individual identification method for the bearing component, the two-dimensional code of the bearing component can be easily and reliably detected, and thus highly accurate individual identification becomes possible.

In the individual identification method for the bearing component,.

Accordingly, the position of the two-dimensional code is detected in the first step and the position and orientation of the two-dimensional code is accurately detected in the second step. As a result, the process until the two-dimensional code is recognized can be performed accurately in a short time.

According to the methods for manufacturing the bearing, the machine, and the vehicle, the individual identification information can be given to each bearing component, so that quality control in the manufacturing process and after product shipment can be easily performed.

A method for reading the two-dimensional code included in the bearing component includes the steps of:.

Accordingly, by detecting the circumferential position of the two-dimensional code from the captured image of the bearing component and then re-imaging the detected circumferential position, a more detailed captured image of the two-dimensional code can be obtained. As a result, the detection accuracy of the two-dimensional code can be improved.

In the method for reading the two-dimensional code,.

Accordingly, the imaging position can be changed only by rotationally driving the bearing component, and thus the captured image of the two-dimensional code can be easily acquired.

In the first step of the method for reading the two-dimensional code, the bearing component can be stopped from rotating and imaged.

Accordingly, it is possible to acquire a captured image without blurring and improve the detection accuracy of the two-dimensional code.

In the first step of the method for reading the two-dimensional code, the bearing component can be imaged while being rotated.

Accordingly, the imaging time can be shortened and the code reading tact time can be shortened.

Accordingly, by moving the imaging optical system, the orientation of imaging can be adjusted in addition to the imaging position, and thus it becomes easy to obtain the captured image suitable for reducing arithmetic processing.

In said first step, the imaging optical system can be stopped to take an image.

Alternatively, an image can be taken while moving the imaging optical system.

In the method for reading the two-dimensional code, in the first step, a plurality of imaging optical systems for imaging the bearing component can be used to image a plurality of different locations in the circumferential direction of the bearing component.

Accordingly, different locations can be simultaneously imaged by the plurality of imaging optical systems, and thus the plurality of captured images can be efficiently acquired in a short time.

When the plurality of locations of the bearing component are sequentially imaged, and when the two-dimensional code is detected in the captured image obtained by imaging, imaging after the imaging location of the captured image can stopped.

Accordingly, unnecessary imaging can be omitted, so that the tact time for two-dimensional code detection can be shortened.

Accordingly, the plurality of imaging optical systems can measure a plurality of locations of stationary receiving parts at a time, and thus a plurality of captured images can be efficiently acquired in a short time. There is no need to use a moving mechanism of the bearing component and the imaging optical system, which simplifies control.

The plurality of imaging optical systems can be arranged at equal intervals in the circumferential direction of the bearing component.

Accordingly, a wide range can be efficiently imaged.

In the method for reading the two-dimensional code, in the first step, the entire bearing component can be imaged in a state where the bearing component is stationary.

Accordingly, it is possible to acquire an image without blurring and improve the detection accuracy of the two-dimensional code.

In the method for reading the two-dimensional code, in the third step, the bearing component can be rotated so that the detected circumferential position of the two-dimensional code is arranged at an imaging position of the two-dimensional code.

Accordingly, the two-dimensional code can be easily and accurately placed at the imaging position by rotating the bearing component.

In the method for reading the two-dimensional code, in the third step, the imaging optical system which images the bearing component can be moved so that the detected circumferential position of the two-dimensional code is arranged at an imaging position of the two-dimensional code.

Accordingly, the imaging optical system can be quickly placed at the imaging position of the two-dimensional code, and thus the tact time can be shortened.

A method for reading the two-dimensional code included in the bearing component includes:.

In said method for reading the two-dimensional code, the information of the two-dimensional code can be read from one of captured images of a captured image group obtained by rotating the bearing component and imaging a plurality of different locations in the circumferential direction of the bearing component.

Accordingly, from the captured image group obtained by moving the bearing component along the circumferential direction, the captured image in which the two-dimensional code is captured can be extracted and the two-dimensional code can be read from the extracted captured image.

In said method for reading the two-dimensional code, the information of the two-dimensional code can be read from one of captured images of a captured image group obtained by moving an imaging optical system for imaging the bearing component and imaging a plurality of different locations in the circumferential direction of the bearing component.

Accordingly, from the captured image group obtained by moving the imaging optical system, the captured image in which the two-dimensional code is captured can be extracted and the two-dimensional code can be read from the extracted captured image.

In said method for reading the two-dimensional code, when a plurality of locations of the bearing component are sequentially imaged, and when information of the two-dimensional code is read from a captured image obtained by imaging, imaging can be stopped after the imaging location of the captured image.

In said method for reading the two-dimensional code,.

Accordingly, the plurality of imaging optical systems can image the plurality of different locations of the bearing component at a time, and thus the plurality of captured images can be efficiently acquired in a short time.

In said method for reading the two-dimensional code, the plurality of imaging optical systems can be arranged at equal intervals in the circumferential direction of the bearing component.

In said method for reading the two-dimensional code, when information of the two-dimensional code can be read from an image captured by at least one of the plurality of imaging optical systems, a reading process of the captured image by the imaging optical systems other than the imaging optical system can be canceled.

Claim 1:
A bearing component which is an annular member (<NUM>, <NUM>) with a two-dimensional code (M) in marked dots which has a shape with a maximum circumferential dimension (Lw) longer than a maximum radial dimension (Lh) or a maximum axial dimension, characterized in that at least one dot row among a plurality of dot rows arranged in a longitudinal direction of the two-dimensional code (M) has a line pattern (<NUM>) in which all dots are marked, wherein said line pattern (<NUM>) has said maximum circumferential dimension (Lw).