JP5326608B2 - Grinding equipment - Google Patents

Description

  The present invention relates to a grinding device used when grinding a raceway groove on the inner periphery of a rolling bearing outer ring or the outer periphery of an inner ring.

  Conventionally, as a grinding device for grinding a raceway groove of an inner ring of a bearing, a work holding means for holding and rotating a work whose inner surface is a surface to be ground, a spindle having a grindstone shaft on which a grinding wheel is mounted, and a work There is known one provided with a notch applying means for moving the holding means and the spindle relative to each other to cause the grindstone to perform a cutting operation on the workpiece, and a notching operation control means for controlling the cutting operation of the notching applying means ( Patent Document 1).

  In order to perform efficient grinding, it is necessary to move the grindstone at a high speed until the grindstone comes in contact with the workpiece and at a low speed after the contact. Contact detecting means for detecting is provided. As the contact detection means, one that determines contact using a sensor such as a force sensor, and one that monitors the power of the spindle driving motor and determines that the grindstone has contacted when the motor power increases. There is.

JP 2007-190638 A

  When a force sensor is used, there is a problem that it is costly and there is a problem that it becomes an obstacle to changeover. Therefore, it is preferable to use a sensorless method. There is a problem that the responsiveness is inferior and malfunction may occur due to disturbance.

  An object of the present invention is to provide a grinding apparatus that can accurately detect contact between a grindstone and a workpiece without using a sensor such as a force sensor.

  A grinding apparatus according to the present invention includes a workpiece holding means for holding and rotating a workpiece, a spindle having a grinding wheel shaft on which a grinding wheel is mounted, and a workpiece holding means and the spindle are relatively moved to move the workpiece to the grinding stone. An in-process gauge for measuring a diameter of a workpiece being ground, and an in-process gauge in a grinding apparatus including a notch applying unit that performs a cutting operation and a cutting operation control unit that controls the cutting operation of the cutting applying unit. A gauge signal processing means for processing the signal, the gauge signal processing means for collecting an in-process gauge value signal for collecting an in-process gauge signal before and after the grindstone contacts the workpiece, and an in-process gauge signal. Filtering means for removing the rotation synchronization signal from the filter and an amplitude for obtaining the amplitude of the rotation synchronization removal signal. And amount calculating means, and is characterized in that it has an amplitude amount and a predetermined contact determination means and the amplitude amount is compared with a threshold is in contact when it becomes smaller than the threshold value.

  This grinding device is used when grinding a raceway groove on the inner periphery of the outer ring of the rolling bearing or on the outer periphery of the inner ring, and is particularly advantageous for grinding a cylindrical roller bearing having a raceway groove of a cylindrical surface.

  The incision imparting means may be a means for fixing the work holding means and sliding the spindle relative to the workpiece in the radial direction of the work, and fixing the spindle to the work holding means in the radial direction of the work. It may be slid. The incision imparting means, for example, causes the grindstone to perform an incision operation on the workpiece by sliding the workpiece holding table in the radial direction (incision direction) of the workpiece with a cutting motor. Grinding is performed by controlling the cutting speed of the cutting applying means (for example, the sliding speed of the work holding means) by the cutting operation control means.

  A grinding process shall consist of indexing, black skin, rough, finishing, and a spark out, for example. At the stage of removing the unevenness on the workpiece surface, the black skin is the “processing” process, and the subsequent roughing, finishing, and sparking out are “at the time of grinding stone contact” between the index and the black skin. The machining is, for example, adaptive control for grinding with a constant grinding load while monitoring the motor power.

  The in-process gauge is used to detect the actual cutting amount and control the cutting operation by measuring the diameter (inner diameter or outer diameter) of the surface to be ground by contacting the tip of the arm with the surface to be ground of the workpiece. A required workpiece diameter (remaining cutting depth) signal is output to the cutting operation control means. The diameter of the workpiece being ground (remaining grinding amount) is measured by an in-process gauge, and the timing of completion of grinding is determined by switching the output signal of the in-process gauge from off to on.

  The in-process gauge signal is conventionally used for measuring the completion timing of machining and has not been used for other applications. However, in the present invention, the signal of the in-process gauge before machining is applied to the grindstone and workpiece. Used for contact detection. Therefore, the conventional in-process gauge is used after contact, but the in-process gauge of the present invention is used before contact. For this reason, an in-process gauge having a measurement range of about 0 to 500 μm (conventionally about 0 to 60 μm) is used.

The in-process gauge signal before and after contact with the grindstone fluctuates greatly due to unevenness on the workpiece processing surface, and contact detection cannot be performed even if the amplitude is obtained, but the grindstone contacts the workpiece and the pressing force against the grindstone When it occurs, the amplitude of the in-process gauge signal converges by performing signal processing (filtering), and thus contact detection can be performed using this. Specifically, the signal processing is performed by removing the rotation synchronization signal using a low-pass filter (LPF) that cuts a frequency higher than the frequency of the work rotation speed. Using the amplitude amount thus obtained, it is possible to detect contact with high accuracy by determining that the time point when the amplitude fluctuation has converged is at the time of wheel contact.

  The in-process gauge signal and spindle motor power signal, etc., are preferably all input to a controller (PLC (programmable logic control), motion controller, etc.) in the grinding machine, and the work holding means moves according to instructions from the controller. Be made.

  According to the grinding apparatus of the present invention, the in-process gauge for measuring the diameter of the workpiece being ground and the gauge signal processing means for processing the signal of the in-process gauge are provided. An in-process gauge value collecting means for collecting in-process gauge signals before and after contact; a filtering means for removing the rotation synchronization signal from the in-process gauge signal; and an amplitude amount calculating means for obtaining an amplitude amount of the rotation synchronization removal signal; And a contact determination means for comparing the amplitude amount with a predetermined threshold value and determining contact when the amplitude amount is smaller than the threshold value. By using the signal of the in-process gauge installed for the It is possible to detect the contact with the click.

FIG. 1 is a diagram schematically showing the overall configuration of a grinding apparatus according to the present invention. FIG. 2 is a graph showing an in-process gauge signal used in contact detection by the gauge signal processing means of the grinding apparatus according to the present invention. FIG. 2 (a) is a graph before LPF processing (displayed together with grinding force data). ) And (b) are after LPF processing. FIG. 3 is a flowchart showing the steps of contact detection of the grinding apparatus according to the present invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an embodiment of a grinding apparatus (1) according to the present invention.

  The grinding machine (1) is equipped with a work holding base (work holding means) (2) that holds and rotates a work (W) whose inner surface is the surface to be ground (track groove), and a grinding wheel (3). A spindle (5) having a rotating grinding wheel shaft (4), a spindle driving motor (spindle driving means) (6) for rotating the grinding wheel shaft (4) of the spindle (5) via a belt (7), and a work holding A cutting motor (cutting means) (8) for moving the table (2) and the spindle (5) relative to each other to cause the grinding wheel (3) to perform a cutting operation on the workpiece (W), and a workpiece being processed (W ) In-process gauge (11) for measuring the inner diameter, controller (cutting motion control means) (12) for controlling the cutting operation by the cutting motor (8), and gauge signal processing for processing the signal of the in-process gauge (11) Means (13).

  The gauge signal processing means (13) includes an in-process gauge value collecting means (14) for collecting an in-process gauge (11) signal (gauge value) before the grindstone (3) contacts the workpiece (W), and an in-process gauge value collecting means (14). The filtering means (15) for removing the rotation synchronization signal from the signal of the process gauge (11), the amplitude amount calculation means (16) for obtaining the amplitude amount of the rotation synchronization removal signal, and comparing the amplitude amount with a predetermined threshold Contact determination means (17) that determines contact when the amplitude amount is smaller than the threshold, and grinding completion that determines the timing of grinding completion when the remaining grinding amount measured by the in-process gauge becomes zero Determination means (18).

  The grinding completion judging means (18) for judging the completion of grinding is conventional, and the conventional in-process gauge value collecting means (14) is an in-process gauge (3) after the grindstone (3) contacts the workpiece (W). 11) The signal (gauge value) is collected. The gauge signal processing means (13) of the grinding apparatus (1) according to the present invention is a signal of the in-process gauge (11) before the grindstone (3) contacts the workpiece (W) by the in-process gauge value collecting means (14). (Gauge value) is collected, and filtering means (15), amplitude amount calculating means (16), and contact determining means (17) are added, so that contact detection can be performed together.

  The grindstone (3) is attached to a quill (4a) having a smaller diameter than that of the grindstone shaft (4) in the housing.

  The in-process gauge (11) includes a casing (11a) in which a processing circuit and the like are housed, and a pair of arms (11b) whose tips are brought into contact with the inner surface of the workpiece (W).

  The controller (12) receives the motor (6) power, dimension data obtained by the in-process gauge (11), etc., and the in-process gauge (11) dimension data, spindle (5) motor power, etc. The sliding speed of the work holder (2) is required by normal adaptive control according to the above. At this time, since the workpiece (W) dimension can be monitored in real time during machining by the in-process gauge (11), grinding with high accuracy becomes possible.

  FIG. 2A shows how the grinding force detected by the force sensor and the remaining grinding amount (becomes 0 at the machining completion position) indicated by the in-process gauge (11) during grinding. The grinding process includes an indexing process, a black skin process, a roughing process, a finishing process, and a spark-out process (SO). FIG. 2A shows only the processes in the indexing process and the black skin process. In the indexing process, the grindstone (3) is not in contact with the workpiece (W), and the grindstone (3) and the workpiece (W) are in contact between the indexing process and the black skin process. In FIG. As shown in FIG. 2 (a), the grinding force detected by the force sensor becomes large at the time of this contact, so that the contact can be detected by using the force sensor. Appropriate grinding can be performed by changing the speed for cutting in (8).

  The in-process gauge signal before and after contact with the grindstone (3) shown in Fig. 2 (a) varies greatly depending on the unevenness of the workpiece (W) processing surface, and contact detection is performed even if the amplitude is obtained. I can't. FIG. 2B shows a result of filtering the in-process gauge signal of FIG. 2A using an LPF (low pass filter). Here, the rotation speed of the workpiece (W) is 23 Hz when converted to a frequency at 1400 rpm, and the set value of the LPF is 20 Hz which is lower than this frequency. Accordingly, FIG. 2B shows that the rotation synchronization signal is removed, and according to this rotation synchronization removal signal, it can be seen that the amplitude amount of the in-process gauge signal converges. That is, contact detection can be performed by comparing the amplitude amount of the rotation synchronization removal signal with a predetermined threshold value and determining that the contact is made when the amplitude amount is smaller than the threshold value.

  FIG. 3 shows a contact detection step by the gauge signal processing means (13).

  In the contact detection by the gauge signal processing means (13), first, the in-process gauge (11) is used before contact (S1), and in-process gauge values are collected (S2). This in-process gauge signal is subjected to LPF processing (S3), and the amplitude amount of the in-process gauge signal is compared with a threshold value (S4). As shown in FIG. 2 (b), the amplitude of the in-process gauge signal is initially large and gradually decreases. Therefore, the amplitude of the in-process gauge signal becomes smaller than the threshold value at a certain point in time. ) Is determined to have touched (S5). The determination result is sent to the controller (12), and the cutting operation control is appropriately performed.

  The in-process gauge (11) is installed to carry out the dimension measurement of the finishing process and the monitoring of the machining completion position. According to the grinding apparatus of the present invention, the in-process gauge (11) is The signal of (11) can be used for detecting contact between the grindstone (3) and the workpiece (W). Thereby, the contact detection can be made sensorless without using a force sensor and the in-process gauge (11) is in contact with the workpiece (W), so that an indirect spindle drive motor ( Compared with the contact detection due to the power increase in 6), there is no malfunction, and the wheel contact detection can be performed stably at high speed. As a result, damage to the grindstone (3) can be reduced, and the machining quality of the workpiece (W) can be improved.

(1) Grinding equipment
(2) Work holding table (work holding means)
(3) Grinding wheel
(4) Wheel axis
(5) Spindle
(8) Cutting motor (cutting means)
(11) In-process gauge
(12) Controller (cutting motion control means)
(13) Gauge signal processing means
(14) Means for collecting in-process gauge values
(15) Filtering means
(16) Amplitude calculation means
(17) Contact judgment means
(W) Workpiece

Claims (1)

A workpiece holding means for holding and rotating a workpiece, a spindle having a grinding wheel shaft mounted with a grinding wheel, and a notch application for moving the workpiece holding means and the spindle relative to each other to cause the grinding wheel to perform a cutting operation on the workpiece. In the grinding apparatus comprising the means, and the cutting operation control means for controlling the cutting operation of the cutting application means,
An in-process gauge for measuring the diameter of the workpiece being ground and a gauge signal processing means for processing the signal of the in-process gauge are further provided. The gauge signal processing means is an in-process gauge before and after the grindstone contacts the workpiece. An in-process gauge value collecting unit that collects the signal of the rotation, a filtering unit that removes the rotation synchronization signal from the signal of the in-process gauge, an amplitude amount calculation unit that obtains an amplitude amount of the rotation synchronization removal signal, an amplitude amount, and a predetermined threshold value And a contact determination means for determining contact when the amplitude amount is smaller than a threshold value.

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