Surface texture estimation device and grinding machine

Abstract

To provide a surface property estimation device configured so that durability of an acceleration sensor can be improved.SOLUTION: A surface property estimation device 2 is provided with a sizing instrument 3 that measures a diameter of a ground peripheral surface W1 of a work-piece W that is ground by a grinding wheel 12 of a grinder 1 and a calculation processing device 20 that estimates a surface property of the ground peripheral surface W1, on the basis of signal data outputted from the sizing instrument 3 after the surface is ground. The sizing instrument 3 has: a contact member 31 that is displaced along concave-convex shapes of the ground peripheral surface W1 of the work-piece W; an energizing member that energizes the contact member 31 so that the contact member comes into contact with the ground peripheral surface W1 of the work-piece W; an acceleration sensor 32 arranged at the contact member 31; and a sensor protection member 4 for protecting the acceleration sensor 32 from at least either of a coolant k and a chip.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a surface texture estimation device and a grinding machine. [Background technology]

[0002] The surface texture estimation device is used to estimate (measure) the surface texture, such as unevenness, of a workpiece rotatably supported by a grinding machine. The grinding wheel surface of the grinding machine is uneven due to the presence of numerous abrasive grains, and these unevenness caused by the abrasive grains are reflected on the surface of the workpiece during grinding. The surface texture formed on the surface of the workpiece changes depending on the grinding conditions, such as the state of the abrasive grains on the grinding wheel, the rotational speed of the grinding wheel, and the rotational speed of the workpiece, as well as the shape of the workpiece. The surface texture estimation device uses a sizing device or the like equipped with a sensor to measure the unevenness occurring in the circumferential and axial directions on the surface of the workpiece, and estimates the surface texture of the workpiece using the results of this unevenness measurement.

[0003] For example, the surface texture estimation system in Patent Document 1 describes that when a measurement position on the surface of a workpiece is moved spirally in the circumferential and axial directions, a sensor in a sizing device detects unevenness on the surface of the workpiece, and generates the surface texture of the workpiece surface based on time-series data related to this detection. The sizing device clamps the workpiece between contacts provided on a pair of contact members, measures the acceleration generated when the contact members vibrate in response to the unevenness on the surface of the workpiece with a sensor, and estimates the surface texture of the workpiece surface by processing the data of the sensor signal. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-79534 Summary of the Invention [Problem to be solved by the invention]

[0005] A sizing device with a sensor is used to measure the diameter of a workpiece ground by the grinding wheel of a grinding machine during grinding. During grinding with a grinding wheel, coolant is supplied to the contact area between the abrasive grains and the workpiece to lubricate the contact area, prevent temperature increases in the contact area, and clean and remove broken or fallen abrasive grains or chips.

[0006] In this case, the sizing device may be located near the workpiece being ground by the grinding wheel. If the sensor of the sizing device is exposed, the sensor may be exposed to coolant or chips, which may cause the sensor to malfunction or shorten its lifespan. In particular, sizing devices used in surface texture estimation devices are often placed in situations where they are likely to be exposed to coolant or chips.

[0007] The present invention has been made in view of the above-mentioned problems, and aims to provide a surface texture estimating device and a grinding machine that can improve the durability of the sensor. [Means for solving the problem]

[0008] One aspect of the present invention is a measuring device that measures the diameter of a grinding surface of a workpiece that is ground by a grinding wheel of a grinding machine during grinding; a processing unit that estimates the surface quality of the grinding peripheral surface based on signal data output from the sizing device after grinding, The sizing device is A sizing device main body, a contact member that is movably provided relative to the sizing device body, that comes into contact with the grinding peripheral surface of the workpiece and displaces in accordance with the irregularities of the grinding peripheral surface; a biasing member that biases the contact member against the sizing device body so that the contact member contacts the grinding peripheral surface; a sensor disposed on the contact member and configured to detect at least one of a displacement of the contact member and an acceleration caused by the displacement of the contact member; and a sensor protection member disposed around the sensor for protecting the sensor from at least one of a coolant used when the grinding peripheral surface is ground and chips generated by the grinding process. death, The sensor a sensor body disposed at a tip end portion of the contact member; a sensor signal line extending from the sensor main body to the rear end side of the contact member, The sensor protection member is a cover having an opening at a rear end side from which the sensor signal line is drawn out and a shape that entirely covers the front end side and the side sides of the sensor main body; a filler material that fills the cover and bonds the sensor and the cover to the contact member. This is a surface texture estimation device. Another aspect of the present invention is a measuring device that measures the diameter of a grinding surface of a workpiece being ground by a grinding wheel of a grinding machine during grinding; a processing unit that estimates the surface quality of the grinding peripheral surface based on signal data output from the sizing device after grinding, The sizing device is A sizing device main body, a contact member that is movably provided relative to the sizing device body, that comes into contact with the grinding peripheral surface of the workpiece and displaces in accordance with the irregularities of the grinding peripheral surface; a biasing member that biases the contact member against the sizing device body so that the contact member contacts the grinding peripheral surface; a sensor disposed on the contact member and configured to detect at least one of a displacement of the contact member and an acceleration caused by the displacement of the contact member; a sensor protection member disposed around the sensor for protecting the sensor from at least one of a coolant used when the grinding peripheral surface is ground and chips generated by the grinding process, The sensor a sensor body disposed at a tip end portion of the contact member; a sensor signal line extending from the sensor main body to the rear end side of the contact member, The sensor protection member is a cover having an opening at the rear end side from which the sensor signal line is drawn out and a shape that covers the entire front end side and side sides of the sensor main body; a relay connector for relaying the connection of the sensor signal line is disposed in the sizing device; The sensor signal line is a first signal line extending from the sensor body to the relay connector; a second signal line drawn out from the relay connector, The contact member is a contactor that contacts the grinding peripheral surface of the workpiece; a feeler to which the contact is attached and which is movably supported on the sizing device body, The surface texture estimation device is configured such that the contactor, the feeler, the sensor main body, the sensor protection member, and the first signal line are detachably attached to the sizing device main body in an integrated state.

[0009] Another aspect of the present invention is a grinding machine equipped with the surface texture estimating device of the above-mentioned aspect. [Effects of the Invention]

[0010] The sizing device in the surface texture estimating device of the above aspect has a sensor protection member for protecting the sensor. The sizing device used in the surface texture estimating device measures the diameter of the grinding peripheral surface of the workpiece during grinding, so it is often placed in a situation where it is likely to be exposed to the coolant used when grinding the grinding peripheral surface or chips generated by the grinding process. In this case, the sensor of the sizing device is covered with the sensor protection member, so that the sensor can be protected from at least one of the coolant and chips. This improves the durability of the sensor.

[0011] According to the surface texture estimating device of the above aspect, the durability of the sensor can be improved.

[0012] According to the grinding machine of the other aspect, the same effects as those of the surface texture estimating device of the above-mentioned aspect can be achieved. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is an explanatory diagram illustrating a grinding machine including a surface texture estimation device according to an embodiment. [Figure 2] FIG. 10 is an explanatory diagram showing the periphery of the sizing device during measurement after grinding of the workpiece according to the embodiment. [Figure 3] FIG. 3 is an explanatory diagram showing an enlarged view of a part of FIG. 2 according to the embodiment. [Figure 4] FIG. 2 is an explanatory diagram showing the periphery of the sizing device during grinding of a workpiece according to an embodiment. [Figure 5] FIG. 10 is an explanatory diagram showing an acceleration sensor of the sizing device as viewed from the rear end side according to the embodiment. [Figure 6] FIG. 4 is an explanatory diagram showing the surface texture of the ground peripheral surface of a workpiece ground by a grinding machine according to an embodiment. [Figure 7] FIG. 1 is an explanatory diagram showing the configuration of a surface texture estimating device according to an embodiment. [Figure 8] FIG. 4 is an explanatory diagram showing divided data of the first spiral data obtained by the acceleration sensor according to the embodiment. [Figure 9]FIG. 10 is an explanatory diagram showing phase alignment data of the first spiral data obtained by the acceleration sensor according to the embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing a chatter map based on first spiral data obtained by an acceleration sensor according to an embodiment. [Figure 11] FIG. 10 is an explanatory diagram showing a radius map based on second spiral data and rotation data from a displacement sensor according to an embodiment. [Figure 12] FIG. 10 is an explanatory diagram showing a surface texture map obtained by combining a chatter map and a radius map according to an embodiment. [Figure 13] 4 is a flowchart showing a grinding process of a grinding machine according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Preferred embodiments of the above-described surface texture estimating device and a grinding machine equipped with the surface texture estimating device will be described with reference to the drawings. (Embodiment)

[0015] 1. Grinding machine 1 configuration The configuration of the grinding machine 1 will be described. As shown in FIG. 1, the grinding machine 1 is equipped with a surface texture estimating device 2. The surface texture estimating device 2 is used as an analyzer for the grinding state of the grinding machine 1. In particular, the surface texture estimating device 2 estimates the surface texture S of the grinding surface W1 of the workpiece W that has been ground by the grinding wheel 12 on the grinding machine 1. The grinding machine 1 is equipped with an image output device 100 that outputs the surface texture S of the grinding surface W1 of the workpiece W estimated by the surface texture estimating device 2 in the form of a surface texture map M as a mapped image.

[0016] The grinding machine 1 grinds the peripheral surface W1 of the workpiece W by rotating the workpiece W and the grinding wheel 12 and moving the workpiece W and the grinding wheel 12 relative to each other. The grinding machine 1 can be applied to a table traverse type grinding machine that traverses the workpiece W, or to a wheelhead traverse type grinding machine that traverses a grinding head 13 that supports the grinding wheel 12. Below, a table traverse type grinding machine will be described as an example of the grinding machine 1.

[0017] The grinding machine 1 includes a bed 11, a grinding wheel 12, a grinding wheel head 13, a headstock 14, a tailstock 15, a spindle table 16, a control device 10, and a surface texture estimating device 2. The workpiece W is supported at both axial ends by the headstock 14 and the tailstock 15, and is driven to rotate by the headstock 14. The shape of the workpiece W is not particularly limited, and may be a columnar, cylindrical, or other shape. As shown in FIG. 2, the grinding peripheral surface W1 of the workpiece W may be not only the outer peripheral surface of a columnar or cylindrical workpiece W, but also the inner peripheral surface of a cylindrical workpiece W.

[0018] In this embodiment, a cylindrical workpiece W is exemplified. The grinding machine 1 brings a grinding wheel 12 into contact with the outer peripheral surface of the rotating workpiece W, which serves as a grinding peripheral surface W1, and grinds the outer peripheral surface of the workpiece W with the grinding wheel 12.

[0019] Here, the direction parallel to the axial direction of the workpiece W supported by the headstock 14 and tailstock 15 is referred to as the Z-axis direction, and the direction perpendicular to the Z-axis direction, in which the grinding wheel 12 approaches the workpiece W, is referred to as the X-axis direction. In each drawing, the Z-axis direction is indicated by the symbol Z, and the X-axis direction is indicated by the symbol X. The grinding wheel 12 is supported by the wheel head 13 in a state where it can rotate around an axis parallel to the Z-axis direction. A wheel head guide 11a is provided on the bed 11, and the wheel head 13 is supported by the wheel head guide 11a so as to be movable in the X-axis direction, and is moved in the X-axis direction by a drive source (not shown) controlled by the control device 10.

[0020] The grinding wheel 12 is driven to rotate by a grinding wheel rotation motor 12a of the grinding wheel head 13, which is controlled by the control device 10. As the grinding wheel head 13 moves in the X-axis direction, the grinding wheel 12 approaches the grinding peripheral surface W1 of the workpiece W and grinds the grinding peripheral surface W1 of the workpiece W.

[0021] The spindle table 16 is supported by a spindle table guide portion 11b provided on the bed 11 so as to be movable in the Z-axis direction, and is moved in the Z-axis direction by a drive source (not shown) controlled by the control device 10. The headstock 14 and tailstock 15 are arranged opposite each other on the spindle table 16. The workpiece W is driven and rotated by a spindle rotation motor 14a of the headstock 14, which is controlled by the control device 10.

[0022] 2. Overview of Surface Texture Estimation Device 2 An overview of the surface texture estimating device 2 will now be described. Fig. 2 shows the surface texture estimating device 2 during measurement after grinding of the workpiece W, and Fig. 4 shows the surface texture estimating device 2 during grinding of the workpiece W (sometimes simply referred to as during processing). As shown in Figs. 2 and 4, the surface texture estimating device 2 includes a sizing device 3 that measures the diameter of the grinding peripheral surface W1 of the workpiece W that is ground by the grinding wheel 12 of the grinding machine 1 during the grinding process, and a calculation processing device 20 that estimates the surface texture S of the grinding peripheral surface W1 based on signal data output from the sizing device 3 after grinding.

[0023] The calculation processing device 20 of this embodiment estimates the uneven surface state caused by the grinding wheel 12, in which the uneven surface of the grinding wheel 12 is transferred to the grinding peripheral surface W1, as the surface quality S, based on the signal data output from the acceleration sensor 32 as a sensor when the sizing device 3 and the workpiece W are moved relative to each other in the Z-axis direction of the workpiece W while rotating the workpiece W.

[0024] 3. Configuration of the sizing device 3 of the surface texture estimation device 2 Next, the sizing device 3 will be described. In this embodiment, as shown in FIG. 2, the outer peripheral surface of a cylindrical workpiece W is ground as a grinding peripheral surface W1, and the sizing device 3 serves as an outer diameter measuring device to measure the outer diameter of the outer peripheral surface of the workpiece W. The sizing device 3 may also measure the inner diameter of the inner peripheral surface of the workpiece W as the grinding peripheral surface W1. The diameter of the grinding peripheral surface W1 of the workpiece W measured by the sizing device 3 is used to switch between grinding processes. However, in this embodiment, the sizing device 3 is also used to estimate the surface texture S of the grinding peripheral surface W1 of the workpiece W by the surface texture estimating device 2.

[0025] The sizing device 3 has a sizing device main body 30, a contact member 31, a biasing member 33, an acceleration sensor 32 as a sensor, and a sensor protection member 4. The sizing device main body 30 is attached to an axial movement device 36 arranged on the bed 11 of the grinding machine 1. The sizing device main body 30 forms a base on which the contact member 31 moves.

[0026] The contact members 31 are movably provided relative to the sizing device main body 30, come into contact with the grinding peripheral surface W1 of the workpiece W, and are displaced to follow the unevenness of the grinding peripheral surface W1. A pair of contact members 31 are provided on the sizing device main body 30, and each contact member 31 has a contactor 311 that contacts the grinding peripheral surface W1 of the workpiece W, and a feeler 312 to which the contactor 311 is attached and which is movably supported on the sizing device main body 30. The contactor 311 is provided at the tip of the feeler 312. The contactors 311 abut against the grinding peripheral surface W1 of the workpiece W at two points on either side of the rotation center O of the workpiece W, and are displaced to follow the uneven surface formed on the grinding peripheral surface W1.

[0027] The feeler 312 is rotatably supported by a rotary shaft 313 on the sizing device main body 30, and rotates in response to the displacement of the contact 311. The displacement of the feeler 312 as it rotates is measured by a displacement sensor 34. The displacement sensor 34 may, for example, be a differential transformer that converts mechanical linear motion into an electrical signal as a displacement amount.

[0028] The sizing device 3 measures the outer diameter of the grinding peripheral surface W1 of the workpiece W by converting the mechanical displacement of the contact 311 into signal data, which is an electrical signal, using the displacement sensor 34. The sizing device 3 also measures the uneven surface condition of the grinding peripheral surface W1 of the workpiece W by converting the acceleration detected by the acceleration sensor 32 into displacement and also into signal data, which is an electrical signal. The signal data from the displacement sensor 34 may be used in combination to measure the uneven surface condition of the grinding peripheral surface W1 of the workpiece W. As shown in FIG. 1, the sizing device 3 can be moved in the Z-axis direction parallel to the central axis of the workpiece W by an axial movement device 36 controlled by the control device 10.

[0029] The biasing member 33 biases the pair of contact members 31 against the sizing device main body 30 so that each of the contact elements 311 of the pair of contact members 31 contacts the grinding peripheral surface W1 of the workpiece W. The biasing member 33 is made up of various springs. The biasing force of the biasing member 33 makes it difficult for the contact elements 311 of the contact members 31 to separate from the grinding peripheral surface W1 of the workpiece W.

[0030] The acceleration sensor 32 is disposed at a position on the tip side of the contact member 31 and detects acceleration accompanying displacement of the contact member 31. Use of the acceleration sensor 32 facilitates measurement of high-frequency components of uneven surfaces on the grinding peripheral surface W1 of the workpiece W. The acceleration sensor 32 is disposed at a tip side portion of the feeler 312 close to the contact 311 in order to properly measure vibrations of the contact 311 caused by unevenness on the grinding peripheral surface W1 of the workpiece W. In other words, as shown in FIG. 4, the acceleration sensor 32 is disposed at a position that is susceptible to the effects of scattering of coolant K or chips when the workpiece W is ground with the grinding wheel 12.

[0031] Fig. 3 shows an enlarged view of a portion of Fig. 2. As shown in Fig. 3, the acceleration sensor 32 has a sensor main body 321 disposed at the tip end of one of the contact members 31, and a sensor signal line 322 drawn from the sensor main body 321 to the rear end side of the one of the contact members 31. In this embodiment, the sensor main body 321 is disposed on the upper contact member 31. The sensor main body 321 is composed of a housing and a sensor element disposed within the housing.

[0032] A relay connector 35 that relays the connection of the sensor signal line 322 is disposed in the sizing device main body 30. The relay connector 35 in this embodiment is attached to the outside of the sizing device main body 30. The relay connector 35 may also be stored inside the sizing device main body 30. The sensor signal line 322 is made up of a first signal line 323 that is drawn from the sensor main body 321 to the relay connector 35, and a second signal line 324 that is drawn from the relay connector 35.

[0033] The relay connector 35 of this embodiment is configured by a first relay connector portion 351 connected to the first signal line 323 and a second relay connector portion 352 connected to the second signal line 324. Then, by fitting the first relay connector portion 351 and the second relay connector portion 352 together, the first signal line 323 and the second signal line 324 are electrically connected.

[0034] The first signal line 323 and the second signal line 324 are configured as coaxial cables in which an inner conductor c1 connected to the arithmetic processing device 20 is disposed inside an outer conductor c2 connected to ground. The thickness of the first signal line 323 is determined by the specifications of the acceleration sensor 32. However, a thinner first signal line 323 is preferable so that the movement of the contact member 31 follows the irregularities of the grinding peripheral surface W1 of the workpiece W. On the other hand, the thickness of the second signal line 324 can be determined arbitrarily. The thickness of the second signal line 324 is larger than the thickness of the first signal line 323. This configuration makes it possible to make the sensor signal line 322 less susceptible to damage.

[0035] 4, the sensor protection member 4 is disposed around the acceleration sensor 32 and protects the acceleration sensor 32 from at least one of the coolant K used when grinding the peripheral surface W1 of the workpiece W and chips generated by the grinding process. The sensor protection member 4 is composed of a cover 41 that covers the sensor main body 321 and a filler material 42 filled inside the cover 41.

[0036] Here, the grinding wheel 12 and the workpiece W face each other in the X-axis direction, and in the sizing device 3, the leading end side refers to the leading end side X1 in the X-axis direction, and the rear end side refers to the rear end side X2 in the X-axis direction. In other words, the leading end side X1 refers to the side on which the grinding wheel 12 is located relative to the sizing device 3, and the rear end side X2 refers to the side opposite to the leading end side. The leading end side X1 and the rear end side X2 are shown in Figures 4 and 5.

[0037] 5 shows the sensor main body 321 and the sensor protection member 4 as viewed from the rear end side X2 of the cover 41, where the opening 411 is formed. The filler material 42 is omitted from the illustration in Fig. 5. The cover 41 has an opening on the rear end side X2, where the first signal line 323 of the sensor signal line 322 is led out, and has a shape that covers the entire tip end side X1 and side sides of the sensor main body 321.

[0038] The sensor main body 321 and a portion of the first signal line 323 are disposed within the cover 41. The sensor main body 321 is attached to the upper surface of the tip of the feeler 312 of the upper contact member 31. The cover 41 entirely covers the tip side X1 of the sensor main body 321, as well as the upper side and a pair of lateral sides. An opening 411 is formed on the rear end side X2 of the cover 41, through which the first signal line 323 is drawn from inside to outside the cover 41. The opening 411 constitutes a supply port for the filler material 42, formed on the rear end side X2 of the sensor main body 321 in the cover 41.

[0039] The filler material 42 is used to adhere the sensor main body 321 and cover 41 of the acceleration sensor 32 to the feeler 312 of the contact member 31. The filler material 42 may be made of various adhesives. In this embodiment, the filler material 42 is made of a two-part epoxy resin adhesive. The sensor main body 321 is placed on the top surface of the tip of the upper feeler 312, and the cover 41 is placed around the sensor main body 321. The filler material 42 is injected from an opening 411 in the cover 41 through which the sensor signal line 322 is drawn out, thereby integrating the sensor main body 321 and the cover 41 with the upper feeler 312.

[0040] 2, the contactor 311, feeler 312, sensor main body 321, sensor protector 4, and first signal line 323 are configured to be attached to and detached from the sizing device main body 30 as an integrated upper contact member 31. In this embodiment, the sensor main body 321 and cover 41 are adhered to the feeler 312 provided with the contactor 311 by means of a filler 42, thereby integrating the feeler 312 provided with the contactor 311, the sensor main body 321, the cover 41, the filler 42, and the first signal line 323 that constitute the upper contact member 31. With this configuration, when the contactor 311 wears out or when a malfunction occurs in the acceleration sensor 32 including the sensor main body 321 and the first signal line 323, the upper contact member 31 can be removed and replaced with another contact member 31, etc.

[0041] 3, in the grinding machine 1, while the workpiece W is being ground by the grinding wheel 12, the outer diameter of the grinding surface W1 of the workpiece W is measured by the displacement sensor 34 of the sizing device 3. An electric signal is sent from the displacement sensor 34 to the control device 10 of the grinding machine 1, and the control device 10 grinds the grinding surface W1 of the workpiece W by the grinding wheel 12 so that the outer diameter of the grinding surface W1 of the workpiece W estimated based on the signal data of the displacement sensor 34 becomes the target outer diameter.

[0042] During grinding of the workpiece W by the grinding wheel 12, coolant K is supplied from the coolant nozzle 122 to the position where the workpiece W is being ground by the grinding wheel 12. The coolant K is used for purposes such as lubrication of the contact area between the abrasive grains of the grinding wheel 12 and the workpiece W, suppressing temperature increases at the contact area, and cleaning and removing broken or fallen abrasive grains or chips. When the coolant K is supplied to the position where the workpiece W is being ground by the grinding wheel 12, it is expected that some of the coolant K will hit the grinding wheel 12 or the workpiece W and scatter in the direction of the contact member 31 of the sizing device 3. It is also expected that chips ground by the grinding wheel 12 will scatter in the direction of the contact member 31 of the sizing device 3.

[0043] 3 shows a case where the grinding wheel 12 and the workpiece W rotate in the same direction at their contact position. The grinding wheel 12 and the workpiece W may also rotate in opposite directions at their contact position.

[0044] During grinding of the workpiece W with the grinding wheel 12, the surface of the cover 41 of the sensor protector 4 that is located on the front end side X1 of the sensor main body 321 faces the side where the grinding wheel 12 is located. During grinding, the opening 411 of the cover 41 on the rear end side X2 of the sensor main body 321 faces the side opposite to the side where the grinding wheel 12 is located. With this configuration, the cover 41 can easily protect the sensor main body 321 of the acceleration sensor 32 from the coolant K and chips. Furthermore, because the opening 411 of the cover 41 does not face the grinding wheel 12, the coolant K or chips can be prevented from hitting the filler material 42 through the opening 411 of the cover 41.

[0045] 4. Other configurations of sensor protection member 4 The sensor protection member 4 may be formed by the cover 41 without using the filler material 42. In this case, the sensor main body 321 may be attached to the feeler 312 or the cover 41 with a fastener such as a screw, and the cover 41 may be attached to the feeler 312 with a fastener such as a screw. Also in this case, by facing the opening 411 of the cover 41 to the side opposite the side where the grinding wheel 12 is located during the grinding process, the coolant K or chips can be prevented from hitting the sensor main body 321 through the opening 411 of the cover 41.

[0046] 5. Surface texture S of the grinding surface W1 of the workpiece W Next, the surface texture S of the grinding peripheral surface W1 of the workpiece W will be described. As shown in Fig. 6, the surface texture S of the grinding peripheral surface W1 of the workpiece W ground by the grinding machine 1 is formed due to various factors. In this embodiment, the surface texture S refers to the surface texture S that is caused by the grinding wheel 12, which is a transfer of the uneven surface as the surface state of the grinding peripheral surface of the grinding wheel 12.

[0047] The surface texture S of the grinding peripheral surface W1 caused by the grinding wheel 12 is separated into a surface texture S1, which is a transfer of the uneven surface of the grinding wheel 12, and a surface texture S2, which is caused by variations in the reference radius in the circumferential direction C of the workpiece W. The surface texture S is generated by combining (adding) the surface textures S1 and S2. The variations in the reference radius in the circumferential direction C of the workpiece W are expressed as circularity, etc., and are thought to be mainly caused by deviations in the distance between the center of the grinding wheel 12 and the center of the workpiece W during grinding.

[0048] 6. Configuration of the arithmetic processing unit 20 of the surface texture estimation device 2 Next, the calculation processing device 20 of the surface texture estimating device 2 will be described. As shown in Fig. 2, after the workpiece W is ground by the grinding wheel 12 in the grinding machine 1, the outer diameter and unevenness of the ground peripheral surface W1 of the workpiece W are measured by the displacement sensor 34 and the acceleration sensor 32 of the sizing device 3, and the uneven surface state of the ground peripheral surface W1 of the workpiece W is estimated. During measurement after grinding, the calculation processing device 20 measures the uneven surface state of the ground peripheral surface W1 of the workpiece W as an uneven surface of low-frequency components detected based on signal data from the displacement sensor 34 and an uneven surface of high-frequency components detected based on signal data from the acceleration sensor 32. During measurement, when measuring the uneven surface condition of the grinding peripheral surface W1 of the workpiece W using the displacement sensor 34 and acceleration sensor 32 of the sizing device 3, the workpiece W is rotated while the sizing device 3 and the workpiece W are moved relative to each other in the Z-axis direction of the workpiece W; in other words, the sizing device 3 is moved spirally relative to the workpiece W in the Z-axis direction.

[0049] As shown in FIG. 7, the arithmetic processing device 20 includes a signal data acquiring unit 21 and a surface texture estimating unit 22. When the sizing device 3 is moved spirally relative to the workpiece W in the Z-axis direction, the signal data acquiring unit 21 acquires signal data from the acceleration sensor 32 of the sizing device 3 and signal data from the displacement sensor 34 of the sizing device 3 in accordance with the uneven surface state of the grinding peripheral surface W1. The signal data from the acceleration sensor 32 is acquired as first spiral data D1 of high-frequency components, and the signal data from the displacement sensor 34 is acquired as second spiral data D2 of low-frequency components. Furthermore, when the workpiece W is rotated while the relative positions of the sizing device 3 and the workpiece W in the Z-axis direction are fixed, the signal data acquiring unit 21 acquires the signal data from the displacement sensor 34 as rotation data D3.

[0050] In FIG. 6, dashed lines indicate the state in which the first spiral data D1 and the second spiral data D2 are measured by the sizing device 3, and the state in which the rotation data D3 is measured by the sizing device 3. The first spiral data D1 and the second spiral data D2 are simultaneously acquired as data for a portion of the grinding peripheral surface W1 of the workpiece W in the Z-axis direction and a portion of the circumferential direction C. The portion of the circumferential direction C of the first spiral data D1 is extracted as a range in which the grinding wheel surface 121 of the grinding wheel 12 is transferred multiple times to the grinding peripheral surface W1 of the workpiece W. Grinding marks caused by each abrasive grain of the grinding wheel 12 repeatedly appear within this portion of the circumferential direction C of the grinding peripheral surface W1. The first spiral data D1 acquired by the acceleration sensor 32 is used to measure the uneven surface condition of the grinding peripheral surface W1 of the workpiece W.

[0051] The second spiral data D2 obtained by the displacement sensor 34 is used to measure the difference in radius of the workpiece W in the Z-axis direction. The difference in radius of the workpiece W in the Z-axis direction can essentially be measured by moving the sizing device 3 relative to the workpiece W in the Z-axis direction. However, the second spiral data D2 is obtained when the contact 311 moves spirally relative to the acceleration sensor 32 in the circumferential direction C and the Z-axis direction simultaneously. Therefore, the change in radius of the grinding circumferential surface W1 of the workpiece W in the Z-axis direction obtained by the second spiral data D2 is excluded from the change in radius of the grinding circumferential surface W1 of the workpiece W in the Z-axis direction and the change in radius of the grinding circumferential surface W1 of the workpiece W in the circumferential direction C.

[0052] The rotation data D3 is acquired as data for the entire circumference in the circumferential direction C at the same position in the Z-axis direction that overlaps with a partial range in the Z-axis direction of the first spiral data D1 and the second spiral data D2. It is considered that the change in radius in the circumferential direction C of the grinding peripheral surface W1 of the workpiece W, as indicated by circularity or the like, is maintained in a similar state in the Z-axis direction. Therefore, it is sufficient to acquire the rotation data D3 at one position in the Z-axis direction. However, to improve accuracy, the rotation data D3 may be acquired at multiple positions in the Z-axis direction within the Z-axis range of the first spiral data D1 and the second spiral data D2.

[0053] 7, the surface texture estimation unit 22 performs signal processing on the first spiral data D1, the second spiral data D2, and the rotation data D3 to estimate the surface texture S of the grinding surface W1 of the workpiece W and create a surface texture map M that visually represents the surface texture S using different colors. The surface texture map M is created by combining a chatter map M1 that shows the surface texture S1 of the grinding surface W1 caused by the uneven surface of the grinding wheel 12 and a radius map M2 that shows the surface texture S2 of the grinding surface W1 caused by errors in the roundness, radius, etc. of the grinding surface W1.

[0054] The chatter map M1 is created by performing signal processing on the first spiral data D1, which is signal data from the acceleration sensor 32. This signal processing is performed by the steps of a gain correction process 221a, a division process 222, a high-frequency component analysis 223a, and a phase alignment process 224. In the gain correction process 221a, it is taken into consideration that the acceleration sensor 32 has input / output characteristics that attenuate output signals for input signals exceeding a specific frequency, and the output signal of the acceleration sensor 32 is corrected for each frequency so that the variation in the output signal is reduced.

[0055] 8, in the division process 222, the first spiral data D1 for the grinding peripheral surface W1 of the workpiece W is divided into a plurality of divided data D11 as data for each position in the circumferential direction C set at a predetermined interval in the Z-axis direction for each position in the Z-axis direction. In the high-frequency component analysis 223a, a fast Fourier transform (FFT) is performed on each divided data D11. Then, for the uneven surface state of the grinding peripheral surface W1 where abrasive marks are repeatedly formed by each abrasive grain of the grinding wheel 12, the formation state of each abrasive mark is extracted as Fourier transform data of high-frequency components represented by frequency (or period) and amplitude.

[0056] Then, specific high-frequency components are extracted to remove noise components from the Fourier transform data of the high-frequency components, and the extracted high-frequency components are subjected to an inverse fast Fourier transform (inverse FFT). This removes noise components from each of the divided data D11. The noise components include noise due to mechanical vibrations, etc.

[0057] 9, in the phase matching process 224, phase matching is performed so that the divided data D11 after noise component removal, which are set at each position in the Z axis direction but shifted to each position in the circumferential direction C, are positioned at the same location in the circumferential direction C, and phase matching data D12 is created. When this phase matching is performed, the phase in the circumferential direction C is finely adjusted so that the uneven surface state of the grinding peripheral surface W1 in the phase matching data D12 does not become intermittent in the Z axis direction. In this way, a chatter map M1 for the first spiral data D1 obtained by the acceleration sensor 32 is created, as shown in FIG.

[0058] The radius map M2 is created by performing signal processing on the second spiral data D2 and rotation data D3, which are signal data from the displacement sensor 34 of the sizing device 3. This signal processing is divided into the steps of gain correction processing 221b and low-frequency component analysis 223b for the second spiral data D2, and gain correction processing 221c and roundness analysis 225 for the rotation data D3. Thereafter, in the roundness component removal processing 226, the second spiral data D2 after the low-frequency component analysis 223b and the rotation data D3 after the roundness analysis 225 are used to acquire the change in radius in the Z-axis direction on the grinding peripheral surface W1 of the workpiece W.

[0059] In the gain correction processes 221b and 221c for the second spiral data D2 and the rotation data D3, it is taken into consideration that the displacement sensor 34 has input / output characteristics that attenuate the output signal for an input signal exceeding a specific frequency, and the output signal for each frequency of the displacement sensor 34 is corrected so that the variation in the output signal is reduced.

[0060] In the low-frequency component analysis 223b of the second spiral data D2, a fast Fourier transform (FFT) is performed on the second spiral data D2, and changes in radius of the grinding peripheral surface W1 of the workpiece W in the Z-axis direction and the circumferential direction C are extracted as Fourier transform data of low-frequency components represented by frequency (or period) and amplitude.

[0061] Then, specific low-frequency components are extracted to remove noise components from the Fourier transform data of the low-frequency components, and an inverse fast Fourier transform (inverse FFT) is performed on the extracted low-frequency components. This removes noise components from the second spiral data D2. The noise components include noise due to mechanical vibrations, etc. The second spiral data D2 also includes changes in the radius of the grinding peripheral surface W1 of the workpiece W in the Z-axis direction.

[0062] In the roundness analysis 225 of the rotation data D3, the amount of unevenness due to roundness error is analyzed in the uneven surface condition of the ground peripheral surface W1 of the workpiece W. Then, in the roundness component removal process 226, the second spiral data D2 after the low-frequency component analysis 223b is compared with the rotation data D3 after the roundness analysis 225, and the effects of unevenness in the circumferential direction C and the Z-axis direction, as well as the effects of unevenness due to roundness error, are removed from the second spiral data D2. Then, radius data indicating the difference in radius for each position in the Z-axis direction is obtained, and a radius map M2 is created based on the radius data, as shown in FIG. 11.

[0063] Thereafter, as shown in Fig. 12, the chatter map M1 and the radius map M2 are combined to create a surface texture map M. In the surface texture map M, the uneven surface condition of the grinding peripheral surface W1 of the workpiece W, which reflects the difference in radius at each position in the Z-axis direction, is visualized by color coding or the like. Fig. 12 shows the width transferred by one rotation of the grinding wheel 12 in the circumferential direction C of the grinding peripheral surface W1 of the workpiece W.

[0064] 7. Grinding process of grinding machine 1 Next, the grinding process of the grinding machine 1 will be described. As shown in FIG. 13, the grinding process is divided into steps based on the feed speed of the grinding wheel 12 in the X-axis direction, and is performed in the following order: rough grinding process St1, fine grinding process St2, fine grinding process St3, and spark-out process St4. The feed speed of the grinding wheel 12 in each step is rough grinding process St1 > fine grinding process St2 > fine grinding process St3 > spark-out process St4. In the rough grinding process St1, the rough shape of the workpiece W is formed. In the subsequent fine grinding process St2 and fine grinding process St3, the feed speed of the grinding wheel 12 is reduced, and the surface shape of the workpiece W is adjusted. In the final spark-out process St4, the surface of the workpiece W is finished, and the workpiece W is completed.

[0065] The diameter of the ground peripheral surface W1 of the workpiece W measured by the sizing device 3 is used to switch between the grinding processes. The control device 10 of the grinding machine 1 has set the diameter of the workpiece W at the time of switching between the rough grinding process St1 and the fine grinding process St2, the diameter of the workpiece W at the time of switching between the fine grinding process St2 and the fine grinding process St3, and the diameter of the workpiece W at the time of switching between the fine grinding process St3 and the spark-out process St4. When the diameter of the workpiece W measured by the sizing device 3 during grinding reaches the set diameter, the control device 10 of the grinding machine 1 switches between the grinding processes.

[0066] Here, the surface texture estimating device 2 preferably estimates the surface texture S of the workpiece W after the spark-out process St4 when grinding is completed. The surface texture estimating device 2 estimates the surface texture S of the workpiece W in-process. The in-process period refers to the period from when the workpiece W is ground until when it is removed from the grinding machine 1, and also includes the period after the spark-out process St4. The surface texture estimating device 2 of this embodiment estimates the surface texture S of the workpiece W after grinding of the workpiece W is completed, while maintaining the rotating state of the workpiece W during grinding.

[0067] 8. Other configurations of the grinding machine 1 As shown in FIG. 1 , the grinding machine 1 may have a determination unit 101 that makes various determinations using a surface texture map M estimated and created by the surface texture estimation device 2. The determination unit 101 may determine whether the grinding of the workpiece W is good or bad based on the surface texture map M. The surface texture estimation device 2 stores a reference surface texture map that serves as a reference for when good grinding of the workpiece W is performed, and the determination unit 101 compares the surface texture map M, which is created each time the grinding of the workpiece W is performed by the grinding machine 1 once or a predetermined number of times, with the reference surface texture map. The determination unit 101 may then compare the surface texture map M with the surface texture in the reference surface texture map and determine that the grinding is poor if the surface texture S of the grinding peripheral surface W1 of the ground workpiece W deteriorates.

[0068] The determination unit 101 may determine the need for adjustment of the machining conditions for the workpiece W to be machined next or thereafter, based on the surface texture map M. The machining conditions for the workpiece W include the rotational speed of the grinding wheel 12 during machining, the rotational speed of the workpiece W during machining, and the feed rate (depth of cut) of the grinding wheel 12 in the X-axis direction. In this case as well, the surface texture estimation device 2 stores a reference surface texture map, and the determination unit 101 compares the surface texture map M created each time grinding of the workpiece W is performed once or a predetermined number of times on the grinding machine 1 with the reference surface texture map. The determination unit 101 may then compare the surface texture map M created each time grinding of the workpiece W is performed once or a predetermined number of times with the reference surface texture map, and determine that adjustment of the machining conditions is necessary when the surface texture S of the grinding peripheral surface W1 of the ground workpiece W deteriorates, as compared with the surface texture in the reference surface texture map.

[0069] The determination unit 101 may determine the need for adjusting the grinding wheel 12 correction timing based on the surface texture map M. The grinding wheel 12 correction timing indicates the frequency at which the grinding wheel 12 is corrected. Corrections to the grinding wheel 12 include truing (reshaping) to correct the runout and shape of the grinding wheel 12, and dressing (dressing) to correct the protrusion amount of the abrasive grains and the creation of the cutting edges of the abrasive grains. In this case, the surface texture estimation device 2 also stores a reference surface texture map, and the determination unit 101 compares the surface texture map M created each time the grinding process of the workpiece W is performed on the grinding machine 1 once or a predetermined number of times with the reference surface texture map. The determination unit 101 may then compare the surface texture map M created each time the grinding process of the workpiece W is performed on the grinding machine 1 once or a predetermined number of times with the reference surface texture map and determine that it is necessary to reduce the frequency at which the grinding wheel 12 is corrected when the surface texture S of the grinding peripheral surface W1 of the ground workpiece W deteriorates by comparing it with the surface texture in the reference surface texture map.

[0070] 9. Action and Effects The sizing device 3 in the surface texture estimating device 2 of this embodiment has a sensor protector 4 for protecting the acceleration sensor 32. The sizing device 3 used in the surface texture estimating device 2 measures the diameter of the grinding peripheral surface W1 of the workpiece W during grinding, and is therefore often placed in a situation where it is susceptible to exposure to the coolant K used when grinding the grinding peripheral surface W1 or to chips generated by the grinding process. In this case, the acceleration sensor 32 of the sizing device 3 is covered by the sensor protector 4, so that the acceleration sensor 32 can be protected from at least one of the coolant K and the chips. This improves the durability of the acceleration sensor 32.

[0071] According to the surface texture estimating device 2 of this embodiment, the durability of the acceleration sensor 32 can be improved.

[0072] The present invention is not limited to the embodiments, and further different embodiments can be configured within the scope of the gist of the present invention. The present invention also includes various modifications, modifications within the scope of equivalents, etc. Furthermore, various combinations of components, forms, etc. envisioned from the present invention are also included in the technical spirit of the present invention. [Explanation of symbols]

[0073] 1 grinding machine 10 Control device 12 Grinding Wheel 2 Surface texture estimation device 20 Processing unit 3 Sizing device 30 Sizing device main body 31 Contact member 311 Contactor 312 Fira 32 Acceleration sensor 321 Sensor body 322 Sensor signal line 323 First signal line 324 Second signal line 33 biasing member 34 Displacement Sensor 35 Relay connector 4 Sensor protection material 41 Cover 411 Opening 42 Filling material W Workpiece W1 Grinding surface S Surface texture

Claims

1. a sizing device that measures the diameter of the grinding surface of the workpiece being ground by the grinding wheel of the grinding machine during the grinding process; a processing unit that estimates the surface quality of the grinding peripheral surface based on signal data output from the sizing device after grinding, The sizing device is A sizing device main body, a contact member that is movably provided relative to the sizing device body, that comes into contact with the grinding peripheral surface of the workpiece and displaces in accordance with the irregularities of the grinding peripheral surface; a biasing member that biases the contact member against the sizing device body so that the contact member contacts the grinding peripheral surface; a sensor disposed on the contact member and configured to detect at least one of a displacement of the contact member and an acceleration caused by the displacement of the contact member; a sensor protection member disposed around the sensor for protecting the sensor from at least one of a coolant used when the grinding peripheral surface is ground and chips generated by the grinding process, The sensor a sensor body disposed at a tip end portion of the contact member; a sensor signal line extending from the sensor main body to the rear end side of the contact member, The sensor protection member is a cover having an opening at a rear end side from which the sensor signal line is drawn out and a shape that entirely covers the front end side and the side sides of the sensor main body; a filler material that fills the inside of the cover and adheres the sensor and the cover to the contact member.

2. a sizing device that measures the diameter of the grinding surface of the workpiece being ground by the grinding wheel of the grinding machine during the grinding process; a processing unit that estimates the surface quality of the grinding peripheral surface based on signal data output from the sizing device after grinding, The sizing device is A sizing device main body, a contact member that is movably provided relative to the sizing device body, that comes into contact with the grinding peripheral surface of the workpiece and displaces in accordance with the irregularities of the grinding peripheral surface; a biasing member that biases the contact member against the sizing device body so that the contact member contacts the grinding peripheral surface; a sensor disposed on the contact member and configured to detect at least one of a displacement of the contact member and an acceleration caused by the displacement of the contact member; a sensor protection member disposed around the sensor for protecting the sensor from at least one of a coolant used when the grinding peripheral surface is ground and chips generated by the grinding process, The sensor a sensor body disposed at a tip end portion of the contact member; a sensor signal line extending from the sensor main body to the rear end side of the contact member, The sensor protection member is a cover having an opening at the rear end side from which the sensor signal line is drawn out and a shape that covers the entire front end side and side sides of the sensor main body; a relay connector for relaying the connection of the sensor signal line is disposed in the sizing device; The sensor signal line is a first signal line extending from the sensor body to the relay connector; a second signal line drawn out from the relay connector, The contact member is a contactor that contacts the grinding peripheral surface of the workpiece; a feeler to which the contact is attached and which is movably supported on the sizing device body, the contactor, the feeler, the sensor main body, the sensor protection member, and the first signal line are configured to be attached to and detached from the sizing device main body in an integrated state.

3. The surface texture estimating device according to claim 1 , wherein the sensor protection member further comprises a filler material that fills the inside of the cover and adheres the sensor and the cover to the contact member.

4. The surface texture estimating device according to claim 3 , wherein an opening that forms a supply port for the filler material is formed in the cover on the rear end side of the sensor main body.

5. a surface of the cover disposed on the tip side of the sensor main body is directed toward a side where the grinding wheel is located during grinding; The surface texture estimating device according to claim 4 , wherein the opening of the cover at the rear end side of the sensor main body faces the side opposite to the side on which the grinding wheel is positioned during grinding.

6. a relay connector for relaying the connection of the sensor signal line is disposed in the sizing device; The sensor signal line is a first signal line extending from the sensor body to the relay connector; The surface texture estimating device according to claim 1 , further comprising: a second signal line extending from the relay connector.

7. The contact member is a contactor that contacts the grinding peripheral surface of the workpiece; a feeler to which the contact is attached and which is movably supported on the sizing device body, 7. The surface texture estimating device according to claim 6, wherein the contactor, the feeler, the sensor main body, the sensor protection member, and the first signal line are configured to be attached to and detached from the sizing device main body in an integrated state.

8. The surface texture estimating device according to claim 2 or 6, wherein the second signal line is thicker than the first signal line.

9. 3. The surface texture estimating device according to claim 1, wherein the arithmetic processing device estimates, as surface texture, an uneven surface state caused by the grinding wheel, which is a transfer of the uneven surface of the grinding wheel to the grinding peripheral surface, based on the signal data output from the sensor when the sizing device and the workpiece are moved relative to each other in the axial direction of the workpiece while rotating the workpiece.

10. A grinding machine equipped with the surface texture estimating device according to claim 1 or 2.

11. 11. The grinding machine according to claim 10, further comprising a judgment unit that executes at least one of judgment on the quality of grinding of the workpiece, judgment on the necessity of adjusting machining conditions for the workpiece to be machined next time onward, and judgment on the necessity of adjusting a timing for correcting the grinding wheel, based on the surface texture estimated by the surface texture estimation device.

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