JP2011020186A - Method and apparatus for double-ended surface grinding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide double-ended surface grinding technology capable of attaining excellent parallelism and flatness on a finished surface of a workpiece and further improving grinding efficiency in grinding both surfaces of the workpiece with large machining allowance. <P>SOLUTION: An apparatus is of a through-feed type in which a workpiece W with a protrusion is fed through between a pair of upper and lower rotating abrasive wheels 1 and 2 and both of its upper and lower surfaces Wa and Wb are surface-ground simultaneously. An abrasive wheel having a chamfered area 6 at the outermost periphery of a surface-grinding abrasive surface 1a is used as the upper abrasive wheel 1, so that the chamfered area 6 forms a pre-grinding abrasive surface at an entrance A of the workpiece of the pair of abrasive wheels 1 and 2. In addition, a tilt angle θ of flat grinding abrasive surfaces 1a and 2a of the pair of abrasive wheels 1 and 2 is specified to correspond to the machining allowance of the workpiece in normal grinding. When the workpiece W is fed through between the abrasive wheels 1 and 2, the workpiece W is pre-ground by a pre-grinding abrasive surface 6, and thereafter the workpiece W is normally ground by the pair of opposite flat grinding abrasive surfaces 1a and 2a. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a double-head surface grinding method and apparatus, and more particularly, particularly in a double-sided grinding of a workpiece, a workpiece with a projection having a projection on a part of a surface to be ground of the workpiece, or a workpiece having a large machining allowance. The present invention relates to a double-sided surface grinding technique that is preferably employed for grinding both surfaces of a workpiece having a relatively large machining allowance.

  In general double-sided surface grinding, for example, double-sided surface grinding by a vertical double-sided surface grinding device in which the rotation spindles of a pair of grinding wheels are vertically arranged, as shown in FIG. .. Are fed between workpieces W, W,... Held in holding pockets d, d,... , Wb are ground simultaneously (through grinding or through feed grinding).

In this case, as shown in FIG. 7B, the flat grinding wheel surfaces a ₁ and b ₁ of the pair of upper and lower grinding wheels a and b are wide on the workpiece inlet A side and narrow on the workpiece outlet B side. Thus, the workpiece W fed between the grinding wheels a and b is ground by a predetermined amount sequentially while passing from the workpiece inlet portion A side to the workpiece outlet portion B side. The Rukoto. That is, the inclination amount (inclination angle) θ of the pair of upper and lower grinding wheels a and b is set according to the size of the machining allowance of the workpiece W, and is set to be small if the machining allowance of the workpiece W is small, and set to be large if it is large. It becomes.

  By the way, about the workpiece W with projections having projections on a part of the ground surfaces Wa and Wb, for example, as shown in FIG. 5, the workpiece W having projections Wc at the central portion of the upper surface Wa which is the ground surface, When RSa and RSb are each 0.1 mm (0.2 mm in total) and the height RSc of the protrusion Wc is 0.2 mm, when grinding is to be performed by double-head surface grinding of the conventional through grinding method, FIG. As shown in FIG. 5, the inclination amount (inclination angle) θ of the pair of upper and lower grinding wheels a and b (in the illustrated case, the inclination amount with respect to the lower grinding wheel b of the upper grinding wheel a) is equal to the height RSc of the projection Wc. Is set to correspond to the vertical machining allowance (= 0.2 mm (upper machining allowance RSa (0.1 mm) + lower taking allowance RSb (0.1 mm))), the protrusion Wc hits the side surface of the inlet portion A of the upper grinding wheel a. Broken, central part of workpiece W Thus missing.

On the other hand, as shown in FIG. 8B, the inclination amount θ of the upper grinding wheel a is set to the total allowance including the height RSc of the projection Wc (= 0.4 mm (the height RSc of the projection Wc (0. 2mm) + upper allowance RSa (0.1mm) + introduction allowance RSb (0.1mm))), the protrusion Wc does not hit the side surface of the inlet portion A of the upper grinding wheel a, and the protrusion Wc breaks. Then, the workpiece W can be machined without chipping (in this case, only the protrusion Wc is first machined after the workpiece W enters (see (i) of FIG. 8B)), and then the entire upper surface Wa of the workpiece W is processed. It hits and is processed (refer to (ii) of Drawing 8 (b)). However, on the other hand, with such a large inclination amount θ, the accuracy of both finished surfaces Wa and Wb of the workpiece W after machining is both parallel and flat as compared with the above-described setting of 0.2 mm. In addition to worsening, the grinding efficiency is reduced, and further, damage due to uneven wear of the grinding wheel surfaces a ₁ and b ₁ of both grinding wheels a and b is increased.

  For this reason, in practice, the double-sided surface grinding apparatus that performs the pre-grinding process first processes and removes only the protrusion Wc of the workpiece W, and then the double-sided surface grinding apparatus that performs the main grinding process, Wb is processed, which causes an increase in the number of devices and an increase in device installation space, as well as an increase in processing time.

  In connection with this point, processing by the compound double-sided surface grinding technique disclosed in Patent Document 1 is also conceivable. However, in this grinding technique, the feed operation of the workpiece W is stopped and the upper grinding wheel a is cut and fed to perform grinding. Processing time is long because the infeed grinding to be performed and the through grinding that simultaneously grinds the upper and lower surfaces (surfaces to be ground) Wa and Wb of the workpiece W with the upper and lower grinding wheels a and b while feeding the workpiece W, When W was a mass-produced product, it was not very suitable.

JP 2000-237941 A

  The present invention has been made in view of such conventional problems, and its object is to provide a machining allowance such as a workpiece with a projection having a projection on a part of a surface to be ground or a workpiece having a large machining allowance. It is an object of the present invention to provide a double-head surface grinding method capable of obtaining excellent parallelism and flatness on a finished surface of a workpiece and further grinding efficiency when grinding both surfaces of a workpiece having a relatively large amount.

  Another object of the present invention is to provide a double-head surface grinding apparatus capable of suitably carrying out the double-head surface grinding method.

  In order to achieve the above object, the double-head surface grinding method of the present invention is a through-feed type in which both surfaces of a workpiece are ground simultaneously while passing the workpiece between a pair of grinding wheels rotating with a flat grinding wheel surface facing each other. In this double-head surface grinding method, a grinding wheel having a chamfered portion on the outermost peripheral portion of the flat grinding wheel surface is used as one grinding wheel of the pair of grinding wheels. The grinding wheel surface for the pre-grinding process at the workpiece entrance of the grinding wheel is configured, and the inclination angle of the flat grinding wheel surface in the pair of grinding wheels is set according to the amount of machining allowance in the main grinding When the workpiece is fed between the pair of grinding wheels, the workpiece is pre-ground with the grinding surface for the pre-grinding step, and then the workpiece is moved with the pair of flat grinding wheels facing each other. Characterized by being configured to grind.

The following configuration is adopted as a preferred embodiment.
(1) The cross-sectional shape dimension of the pre-grinding process grinding wheel surface in the grinding wheel is set according to the shape dimension of the part to be ground in the work to be pre-ground process.

(2) The pre-grinding process grindstone surface is a curved surface having an R-shaped cross-sectional contour that continues to the flat grinding grindstone surface.

(3) The grindstone surface for the pre-grinding step is a conical surface having a linear cross-sectional contour that continues to the flat grindstone surface.

(4) The pre-grinding grinding wheel surface having the linear cross-sectional outline is configured to have a function as a spark-out grinding wheel surface in the workpiece outlet portion of the pair of grinding wheels.

(5) A plurality of holding pockets are provided at predetermined intervals on a carrier passing between the pair of grinding wheels so as to be able to remove the workpieces. The workpieces held in the holding pockets are moved by the carrier feeding operation. A plurality of workpieces are successively and continuously ground through the grinding wheels.

(6) The grinding wheel portion forming the grinding wheel surface of the grinding wheel is constituted by a conductive grinding wheel in which abrasive grains are bonded by a conductive bonding material, and is used for the flat grinding wheel surface and the pre-grinding step of the grinding wheel. The grindstone surface is formed by discharge truing.

(7) When the discharge truing is performed, the grinding wheel is moved in the axial direction of the rotating shaft while moving the discharge truing electrode in a direction perpendicular to the rotating shaft of the grinding wheel, thereby making the grinding wheel flat. A grinding wheel surface and a grinding wheel surface for a pre-grinding process are formed.

  Further, a double-head surface grinding apparatus of the present invention is an apparatus suitable for carrying out the double-head surface grinding method, and is a grinding apparatus for simultaneously surface grinding both surfaces of a workpiece, and is disposed so as to be opposed to be rotatable. A pair of grinding wheels having flat grinding wheel surfaces facing each other, a rotation driving means for rotationally driving these grinding wheels, and a plurality of grinding wheels arranged so as to be able to pass between the grinding wheel surfaces of the two grinding wheels. A carrier having a holding pocket; feed driving means for feeding and driving the carrier; and control means for driving and controlling the rotation driving means and the feed driving means in conjunction with each other. One of the grinding wheels is in the form of a grinding wheel having a chamfered portion on the outermost peripheral portion of the flat grinding wheel surface, and the chamfered portion of the grinding wheel is used for a pre-grinding step at a work inlet portion of the pair of grinding wheels. Grinding Constitute a surface inclination angle of the flat grinding wheel surface in the pair of grinding wheels is characterized in that it is set to correspond to the size of the allowance of the workpiece in the grinding.

The following configuration is adopted as a preferred embodiment.
(1) The cross-sectional shape dimension of the pre-grinding process grinding wheel surface in the grinding wheel is set according to the shape dimension of the part to be ground in the work to be pre-ground process.

(2) The workpiece to be ground is a workpiece with a projection having a projection as a portion to be ground to be a target to be ground on a part of the ground surface, and the grindstone surface for the pregrinding step is the flat surface The curved surface has an R-shaped cross-sectional contour that continues to the grinding wheel surface.

(3) The workpiece to be ground is a workpiece having a large machining allowance to be subjected to the pre-grinding process, and the grinding wheel surface for the pre-grinding process has a linear cross-sectional contour that continues to the flat grinding wheel surface. It has a conical surface.

(4) The pre-grinding grinding wheel surface having the linear cross-sectional outline is configured to have a function as a spark-out grinding wheel surface in the workpiece outlet portion of the pair of grinding wheels.

(5) The grinding wheel portion forming the grinding wheel surface of the grinding wheel is composed of a conductive grinding wheel formed by bonding abrasive grains with a conductive bonding material, and a discharge truing device that discharges the grinding wheel surface. In addition, a flat grinding wheel surface for grinding of the grinding wheel and a grinding wheel surface for a pre-grinding step are formed by the discharge truing device.

  The double-head surface grinding method of the present invention is a through-feed type in which both surfaces of a workpiece are simultaneously ground while passing the workpiece between a pair of grinding wheels rotating with a flat grinding wheel surface facing each other. By using a grinding wheel having a chamfered portion on the outermost peripheral portion of the flat grinding wheel surface as one grinding wheel of the pair of grinding wheels, this chamfered portion is pre-ground at the work entrance portion of the pair of grinding wheels. The grinding wheel surface for the process is configured, and the inclination angle of the flat grinding wheel surface in the pair of grinding wheels is set corresponding to the size of the machining allowance in the main grinding, and the workpiece is placed between the pair of grinding wheels. Since the workpiece is pre-ground by the pre-grinding process grinding wheel surface and then the workpiece is ground by the pair of flat grinding wheel surfaces facing each other, When grinding both sides of workpieces with relatively large machining allowances, such as workpieces with projections that have projections on a part of the surface to be ground and workpieces with large machining allowances, It is possible to provide a double-head surface grinding method capable of obtaining excellent parallelism and flatness on a surface and further grinding efficiency.

(1) The process (pre-grinding process) of removing the protrusions of the workpiece in advance can be omitted.
Since the chamfered portion of the grinding wheel acts as a grinding wheel surface for the pre-grinding process at the workpiece entrance portion of the pair of grinding wheels, when a workpiece with a large machining allowance, for example, a workpiece with a protrusion is fed between the pair of grinding wheels, the pre-grinding is performed. The grinding wheel surface for the process removes most or all of the protrusions by pre-grinding, and a pair of flat grinding wheel surfaces main-grinds both surfaces of the workpiece when passing between the grinding wheels thereafter. Thereby, the process (pre-grinding process) which remove | eliminates previously the processus | protrusion of the workpiece | work previously performed with another double-head surface grinding apparatus becomes unnecessary.

  This makes it possible to realize double-head surface grinding in which the pre-grinding process is omitted even for a workpiece having a large machining allowance that requires a pre-grinding process by another double-head surface grinding apparatus as in the prior art.

(2) The number of devices can be reduced and the space of the devices can be saved.
As described above, as a result of eliminating the need for a separate double-sided surface grinding device for the previous process, the number of installed double-sided surface grinding devices can be halved and the installation space can be greatly reduced (space saving). .

(3) The processing time can be shortened.
As above, the process time (grinding cycle) per workpiece is shortened as a result of eliminating the pre-grinding process to remove workpiece protrusions in advance or to remove most of the large machining allowance. This is particularly noticeable in double-sided grinding of workpieces that are mass-produced products, and can greatly reduce costs.

(4) Highly versatile double-side grinding is possible.
By simply setting and adjusting the chamfered portion of the flat grinding wheel surface corresponding to the shape of the workpiece to be ground (height of protrusions and the amount of machining allowance), It is possible to cope with double-side grinding of workpieces of geometric dimensions, and as a result, highly versatile double-side grinding can be realized.

  In this connection, the grinding wheel portion forming the grinding wheel surface of the grinding wheel is composed of a conductive grinding wheel in which abrasive grains are bonded by a conductive bonding material, and is used for the grinding wheel surface and pre-grinding process of the grinding wheel. By forming the grinding wheel surface by discharge truing, it is not necessary to separate the truing of the chamfered portion and the truing of the other grinding wheel surfaces as separate truing processes, and truing of all the grinding wheel surfaces at once as one truing process. Therefore, it is not necessary to extend the truing time due to the presence of the chamfered portion (the grindstone surface for the pre-grinding process), and the truing time can be substantially shortened.

(5) High precision double-sided grinding is possible.
In addition to the unique effects (1) to (4) obtained when performing double-side grinding of a workpiece having a relatively large machining allowance, a pair of grinding wheels can be used for both-side grinding of a workpiece having a general machining allowance. By effectively using the grinding wheel surface for the pre-grinding process at the workpiece entrance, it is possible to set the inclination angle of the flat grinding wheel surface in a pair of grinding wheels smaller than in the past. Double-sided grinding can be realized.

It is a front view which shows schematic structure of the principal part of the double-head surface grinding apparatus which is Embodiment 1 which concerns on this invention. FIGS. 2A to 2C are front views for explaining a grinding process in the double-head surface grinding apparatus. It is a perspective view which shows schematic structure of the double-headed surface grinding apparatus. FIG. 4A is a diagram for explaining discharge truing of the upper grinding wheel in the double-sided surface grinding apparatus. FIG. 4A shows a process of continuously truing the flat grinding wheel surface of the upper grinding wheel and the grinding wheel surface for the pre-grinding process. FIG. 4B is an enlarged front view showing the sectional contour shape of the pre-grinding grinding wheel surface of the upper grinding wheel. FIG. 5A is a perspective view, and FIG. 5B is a front view, illustrating a workpiece with protrusions to be ground by the double-head surface grinding apparatus. It is a front view which shows schematic structure of the principal part of the double-head surface grinding apparatus which is Embodiment 2 which concerns on this invention. FIG. 7A is a perspective view showing a schematic configuration corresponding to FIG. 3, and FIG. 7B is a front view showing a schematic configuration corresponding to FIG. 1. Fig. 8 (a) shows the state of grinding on both sides of a workpiece with projections by the conventional double-head surface grinding machine. Fig. 8 (a) corresponds to the vertical machining allowance excluding the height of the workpiece projections. FIG. 8B shows a case where the tilt amount of the pair of upper and lower grinding wheels is set corresponding to the total machining allowance including the height of the projection of the workpiece.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Throughout the drawings, the same reference numeral indicates the same component or element.

Embodiment 1
A double-sided surface grinding apparatus according to the present invention is shown in FIGS. 1 to 4, and specifically, this grinding apparatus is such that the rotation main shafts 10 and 11 of a pair of upper and lower grinding wheels 1 and 2 are vertically arranged. 5 is a through-grinding method (or through feed) for a workpiece W with protrusions as shown in FIG. 5 (in the illustrated case, the protrusion Wc has a protrusion Wc at the central portion of the upper surface Wa). It is a configuration suitable for grinding by double-sided surface grinding of a grinding method).

  As shown in FIG. 3, the double-head surface grinding apparatus includes the pair of grinding wheels 1, 2, carrier device 3, truing device 4, and control device (control means) 5 as main parts.

  The pair of grinding wheels 1 and 2 are so-called cup-type grinding wheels. The grinding wheel surfaces 1a and 2a are flat surface grinding wheels, and both the surface grinding wheels 1a and 2a are predetermined. Oppositely arranged with an inclination amount (inclination angle) θ. In the illustrated case, the surface grinding wheel surface 1 a of the upper grinding wheel 1 is disposed opposite to the surface grinding wheel surface 2 a of the lower grinding wheel 2 with a predetermined inclination angle θ. Further, one of the pair of upper and lower grinding wheels 1, 2, specifically, the upper grinding wheel 1 is configured as a grinding wheel having a chamfered portion 6 on the outermost peripheral portion of the surface grinding wheel surface 1 a. .

  Specifically, as shown in FIGS. 1 and 3, the two surface grinding wheel surfaces 1a and 2a are wide at the workpiece inlet portion A side and narrow at the workpiece outlet portion B side. Inclined with θ. As will be described later, the inclination angle θ corresponds to the size of the machining allowance of the workpiece W (upper machining allowance RSa + the lower machining allowance RSb) in the main grinding, and the parallelism and flatness required for the finished surfaces Wa and Wb of the workpiece W. It is set to an optimum value in consideration of the degree or grinding efficiency. Thereby, as will be described later, the workpiece W fed between the grinding wheels 1 and 2 is ground by a predetermined amount sequentially while passing from the workpiece inlet side A to the outlet side B.

  Further, the chamfered portion 6 at the outermost peripheral portion of the surface grinding wheel surface 1a of the upper grinding wheel 1 constitutes a grinding surface for a pre-grinding process at the workpiece entrance portion A of the pair of grinding wheels 1, 2, as will be described later. The cross-sectional shape dimension of the pre-grinding process grinding wheel surface 6 is set in accordance with the shape dimension of the part to be ground in the workpiece W which is the object of the pre-grinding process.

  The grindstone surface 6 for the pre-grinding process in the illustrated embodiment is a curved surface having an R-shaped cross-sectional contour that continues from the surface grinding grindstone surface Wa. The specific cross-sectional shape dimensions (the curvature of the R-shaped cross-sectional contour, the height dimension H, the lateral dimension L, etc. in FIG. 4B) of the pre-grinding grinding wheel surface 6 are the position and height of the projection Wc of the workpiece W. Is set corresponding to RSc.

  The grinding wheel portions forming the surface grinding wheels 1a and 2a of the grinding wheels 1 and 2 are electrically conductive in which abrasive grains are bonded by a conductive bonding material so that discharge dressing and truing (discharge truing) described later is possible. It is composed of a characteristic grindstone.

  Specifically, the grindstone portion uses so-called superabrasive grains such as fine diamond abrasive grains or CBN abrasive grains as the abrasive grains, and contains a metal bond or a conductive substance as a binding material for these abrasive grains. Conductive resin bonds are used. In the illustrated embodiment, a metal bond CBN grindstone is used as the conductive grindstone of the grinding wheels 1 and 2. The surface grinding wheels 1a, 2a and the pre-grinding grinding wheel surface 6 made of such a conductive grinding wheel have a strong holding force for abrasive grains and are not easily deformed, and the shape is corrected by discharge truing. As a result, the protruding amount of the abrasive grains can be taken sufficiently and the sharpness becomes good.

  Although not specifically shown, the rotation spindles 10 and 11 of the pair of upper and lower grinding wheels 1 and 2 are respectively connected to a spindle motor that is a rotation drive source via a power transmission mechanism such as a rotation drive means, for example, a gear mechanism. In addition to being linked, the cutting means is linked to a lifting device such as a lifting cylinder. These two grinding wheels 1 and 2 can be independently rotated and moved up and down.

  The carrier device 3 holds the workpiece W and feeds it between the upper and lower grinding wheels 1 and 2 so that it can pass between the grinding wheels 1a and 2a of both the grinding wheels 1 and 2. The arranged carrier 12 and a feed drive unit (feed drive means) (not shown) for feeding and driving the carrier 12 are configured as main parts.

  The carrier 12 is in the form of a rotating disk that rotates around its center, and as shown in FIG. 3, the outer periphery of the carrier 12 passes between the grinding wheels 1a and 2a of the grinding wheels 1 and 2 described above. Are arranged horizontally.

  The illustrated carrier 12 is made of a thin disk made of a metal such as stainless steel or a resin such as plastic, and has a thickness smaller than the clearance between the grinding wheels 1a and 2a of the grinding wheels 1 and 2 described above. A plurality of holding pockets 13, 13,... Holding the workpiece W are vertically penetrated in a predetermined arrangement relation in the circumferential direction on the outer peripheral portion of the carrier 12 having a size and passing between the grinding wheel surfaces 1 a and 2 a. Has been.

Although not specifically shown, a guide portion that slides and guides the lower surface of the carrier 12 is provided below the carrier 12, and the workpieces W, W,... Supplied by the workpiece supply portion P1 are carriers. 12, the workpiece is smoothly guided to the workpiece collection unit P <b> 2 through the upper and lower grinding wheels 1 and 2.

  A carrier shaft (not shown) that is a rotation main shaft of the carrier 12 is rotatably supported in a vertical state and is drivingly connected to the feed driving unit. Although not specifically illustrated, the feed drive unit includes a rotation drive source such as a servo motor, and the rotation drive source is electrically connected to a control device 5 described later.

  Then, the carrier 12 rotates at a predetermined speed in the direction of the arrow in FIG. 3 by driving the feed driving unit, and the work supply unit P1 holds the holding pockets 13, 13,... .. Are fed sequentially and continuously between the pair of upper and lower grinding wheels 1 and 2 from the workpiece inlet A to the workpiece outlet B, and the upper surface is provided by the pre-grinding process grinding wheel surface 6. The upper and lower surfaces Wa and Wb are simultaneously subjected to surface grinding while removing the protrusion Wc of Wa, and then recovered by a workpiece recovery device (not shown) at the workpiece recovery unit P2.

  The truing device 4 applies truing to the surface grinding wheel surfaces 1a, 2a and the pre-grinding process grinding wheel surface 6 of the upper and lower grinding wheels 1 and 2 periodically or at an appropriate interval. The discharge truing apparatus is provided with a discharge truing electrode 15 for discharging truing the surfaces 1a, 6, 2a.

  The discharge truing electrode 15 is an electrode for performing discharge truing on the surface grinding wheel surfaces 1a and 2a of the upper and lower grinding wheels 1 and 2 and the grinding wheel surface 6 for the pre-grinding process to form a grinding wheel surface shape having a predetermined profile. In this embodiment, a rotary electrode is used as this electrode.

  As shown in FIG. 4 (a), the rotary electrode 15 is in the form of a narrow and small disk-like electrode disposed so as to be inserted and passed between the surface grinding wheels 1a and 2a of the upper and lower grinding wheels 1 and 2. The outer peripheral surface 15a is a truing surface. Although not specifically illustrated, the rotary electrode 15 is rotatably supported by a truing base, and the rotary electrode 15 is linked to a rotational drive source via a power transmission mechanism. Thereby, the rotary electrode 15 is rotationally driven in a state in which the truing surface 15a is disposed opposite to the grinding wheel surfaces 1a, 6, 2a of the grinding wheels 1, 2.

  Although not shown, an electrode driving device is provided for moving the rotary electrode 15 along the grinding wheel surfaces 1a, 6, 2a. In the illustrated embodiment, the electrode driving device rotates the rotary electrode 15 under the control of the control device 5 and traverses the rotary electrode 15 between the grinding wheels 1 and 2 in the horizontal direction of FIG. It is configured to move.

  In this connection, the upper grinding wheel 1 is configured to be raised and lowered in the vertical direction in response to the horizontal movement of the rotary electrode 15, and in accordance with a discharge truing program of the control device 5 described later. The surface grinding wheel surface 1 a and the pre-grinding process grinding wheel surface 6 are continuously trued by the rotary electrode 15.

  The rotary electrode 15 is electrically connected to a negative (−) electrode of a DC power supply device (not shown) to be a discharge truing electrode of a (−) electrode, while the positive (+) electrode of the DC power supply device is the above-mentioned It is electrically connected to the grinding wheels 1 and 2.

  And according to the properties of the surface grinding wheel surface 1a and the pre-grinding process grinding wheel surface 6 of the upper grinding wheel 1 and the surface grinding wheel surface 2a of the lower grinding wheel 2 according to the discharge truing program of the control device 5 described later, While the rotary electrode 15 is driven to rotate, it traverses between the rotating grinding wheels 1 and 2, and the grinding wheel surfaces 1a, 6, and 2a are melted and removed by a discharge action to form a predetermined shape. In particular, with respect to the surface grinding wheel surface 1a of the upper grinding wheel 1 and the grinding wheel surface 6 for the pre-grinding process, the upper grinding wheel 1 moves up and down in synchronization with the traverse movement of the rotary electrode 15, as shown in FIG. Up and down, the straight cross-sectional contour of the surface grinding wheel surface 1a and the R-shaped cross-sectional contour of the pre-grinding process grinding wheel surface 6 (the curvature of the R-shaped cross-sectional contour in FIG. Dimension L etc.) are continuously trued.

  The control device 5 interlocks the rotational drive means and the cutting means of the grinding wheels 1 and 2, the feed drive portion of the carrier device 3, the drive portion of the workpiece supply device and the workpiece recovery device, and the drive portion of the truing device 4. In particular, it is automatically controlled, and is specifically composed of a microcomputer comprising a CPU, a RAM, a ROM, an I / O port, and the like.

  This control device 5 is electrically connected to each of the above-described constituent means and drives and controls each of the constituent means so as to automatically execute the double-head surface grinding method and discharge truing described below.

  Therefore, in the through grinding of the workpiece W by the double-head surface grinding apparatus configured as described above, the workpieces W, W,... When supplied to and supplied to the workpieces W, W,..., The workpieces W, W,... 2, the upper and lower surfaces Wa and Wb are successively ground while being fed from the workpiece inlet A to the workpiece outlet B, and then the holding pockets 13 and 13 of the carrier 12 are Are dropped and discharged from the workpiece and collected by the workpiece collecting device.

  In this case, when paying attention to one workpiece W that is fed between the upper and lower pair of grinding wheels 1 and 2 from the workpiece inlet A to the workpiece outlet B, the workpiece W is firstly paired with the upper and lower grinding wheels 1 and 2. In the workpiece entrance portion A, all or most of the protrusions Wc of the upper surface Wa are ground and removed by the pre-grinding process grinding wheel surface 6 of the upper grinding wheel 1 (operation as a pre-grinding process) (FIG. 2A). After that, while passing further between the grinding wheels 1 and 2, the upper and lower surfaces Wa and Wb are subjected to main grinding by a pair of surface grinding wheels 1a and 2a facing the grinding wheels 1 and 2 (FIG. 2 ( (See b)) When exiting from the workpiece exit B, the final finish dimension defined by the upper and lower surface grinding wheels 1a and 2a at the workpiece exit B is finished.

  Further, if the properties of the surface grinding wheel surfaces 1a and 2a of the upper and lower grinding wheels 1 and 2 and the grinding wheel surface 6 for the pre-grinding process deteriorate with time due to continuous grinding, the grinding wheel surfaces of the grinding wheels 1 and 2 Depending on the properties of 1a, 6, and 2a, the discharge truing by the truing device 4 described above is performed at regular intervals or at appropriate intervals, the shape is corrected, and a predetermined profile is recovered and maintained. According to this discharge truing, there is no need to separate the truing of the chamfered portion (grinding wheel surface for pre-grinding process) 6 and the truing of the other grindstone surface 1a as separate truing processes, and one truing process at a time. The truing of the grindstone surfaces 1a and 6 is possible, and therefore, it is not necessary to extend the truing time due to the presence of the chamfered portion (the grindstone surface for the pre-grinding process) 6.

  Specifically, the discharge truing electrode 15 of the truing device 4 traverses in the radial direction of the grinding wheel 1 along the grinding wheel surfaces 6 and 1a of the grinding wheel 1 (range corresponding to the lateral radius of the grinding wheel 1 in FIG. 4). ), Truing continuously in the order of the grinding wheel surface 6 for the pre-grinding process → the surface grinding wheel surface 1a → the surface grinding wheel surface 1a → the grinding wheel surface 6 for the pre-grinding process, whereby all the grinding wheel surfaces 1a of the grinding wheel 1 As a truing process, truing 6 is performed at once.

  As described above in detail, according to the double-sided surface grinding method of the present embodiment, as the upper grinding wheel 1, a grinding wheel having a chamfered portion 6 on the outermost peripheral portion of the surface grinding wheel surface 1a is used. 6 constitutes the grinding surface for the pre-grinding process at the workpiece entrance A of the pair of grinding wheels 1 and 2, and the inclination angle of the flat grinding wheel surface in the pair of grinding wheels 1 and 2 is determined as the workpiece in the main grinding. When the workpiece W is fed between the upper and lower pair of grinding wheels 1 and 2, the pre-grinding process grinding wheel surface 6 moves the projection Wc of the workpiece W forward. After grinding, the upper and lower surfaces Wa, Wb of the workpiece W are ground by the pair of opposing surface grinding wheels 1a, 2a. Therefore, the effects listed below are obtained, and the finished surface of the workpiece W is finished. Excellent in Wa and Wb Parallelism and flatness, it is possible to further obtain the grinding efficiency.

(A) The step (pre-grinding step) of removing the protrusion Wc of the workpiece W in advance can be omitted.
That is, since the chamfered portion 6 of the upper grinding wheel 1 acts as a grinding surface for the pre-grinding process at the workpiece entrance A of the pair of upper and lower grinding wheels 1 and 2, the workpiece W with protrusions as shown in FIG. When fed between the wheels 1 and 2, the pre-grinding process grinding wheel surface 6 removes most or all of the protrusions Wc by pre-grinding, and then passes between the grinding wheels 1 and 2, a pair of surface grinding wheels. The surfaces 1a and 2a perform main grinding on both surfaces Wa and Wb of the workpiece W. Thereby, the process (pre-grinding process) which remove | eliminates previously the processus | protrusion Wc of the workpiece | work W previously performed with another double-head surface grinding apparatus becomes unnecessary.

(B) The number of devices is reduced, and the space of the devices can be saved.
As described above, as a result of eliminating the need for a separate double-sided surface grinding device for the previous process, the number of installed double-sided surface grinding devices can be halved and the installation space can be greatly reduced (space saving). .

(C) The processing time can be shortened.
Similar to the above, the pre-grinding step for removing the protrusion Wc of the workpiece W in advance is not necessary, and as a result, the machining time (grinding cycle) per workpiece W is shortened. This is remarkable in double-sided grinding, and can greatly reduce the cost.

(D) Highly versatile double-side grinding is possible.
The shape dimension of the chamfered portion 6 provided on the outermost peripheral portion of the surface grinding wheel surface 1a of the upper grinding wheel 1 is the shape dimension of the workpiece W to be ground (the height RSc of the projection Wc and the machining allowances RSa and RSb). It is possible to cope with double-side grinding of workpieces W having various shapes and dimensions by simply setting and adjusting in accordance with the above. As a result, highly versatile double-side grinding can be realized.

  In this connection, the grindstone portion 6 that forms the grinding wheel surface of the upper grinding wheel 1 is composed of a conductive grindstone in which abrasive grains are bonded by a conductive bonding material, and the grinding wheel surface 1a of the grinding wheel 1 is formed. In addition, by forming the pre-grinding process grindstone surface 6 by electric discharge truing, it is not necessary to separately perform truing of the chamfered portion (pre-grinding process grindstone surface) 6 and other truing of the grindstone surface 1a. As a truing process, truing of all the grindstone surfaces 1a and 6 can be performed at a time. Accordingly, it is not necessary to extend the truing time due to the presence of the chamfered portion (grinding wheel surface for pre-grinding process) 6, and the truing time can be substantially shortened.

(E) High-precision double-side grinding is possible.
In addition to the above-mentioned effects (A) to (D), which are obtained when performing double-side grinding of workpieces W with relatively large machining allowances RSa and RSb, double-sided grinding of workpieces W with common machining allowances RSa and RSb. At this time, the inclination angle θ of the flat grinding wheel surfaces 1a and 2a in the pair of grinding wheels 1 and 2 can be effectively utilized by using the grinding surface 6 for the pre-grinding process in the workpiece entrance A of the pair of grinding wheels 1 and 2. Can be set to be smaller than in the prior art, and thereby, more accurate double-side grinding can be realized.

Embodiment 2
This embodiment is shown in FIG. 6, and is intended for grinding a workpiece W having a large machining allowance.

  That is, the workpiece W to be ground in the present embodiment is a workpiece having a large machining allowance to be subjected to the pre-grinding process, and correspondingly, the grinding wheel surface 6 for the pre-grinding process of the upper grinding wheel 1 is surface ground. It is set as the conical surface which has the linear cross-sectional outline which continues on the grindstone surface 1a.

  Further, the pre-grinding process grindstone surface 6 having the linear cross-sectional contour has a work exit portion in addition to the function as the original pre-grinding process grindstone surface in the work entrance part A of the pair of upper and lower grinding wheels 1 and 2. It is comprised so that it may also have a function as a grindstone surface for spark out in B.

  That is, as shown in FIG. 6, the grinding wheel surface 6 for the pre-grinding process of the upper grinding wheel 1 at the workpiece entrance A is similar to the surface grinding grinding wheel surface 2 a of the lower grinding wheel 2 at the workpiece entry B. It arrange | positions so that it may have a horizontal linear cross-sectional outline, and it is comprised so that it may become parallel to the surface grinding wheel surface 2a of the lower grinding wheel 2. FIG.

In the double-head surface grinding apparatus configured as described above, the workpiece W having a large machining allowance is fed between the pair of upper and lower grinding wheels 1 and 2 from the workpiece inlet A to the workpiece outlet B. First, in the workpiece entrance portion A of the pair of upper and lower grinding wheels 1 and 2, a portion on the upper surface Wa side of the workpiece W is largely ground by the grinding surface 6 for the pre-grinding process of the upper grinding wheel 1 (as a pre-grinding process) (Refer to the solid line in FIG. 6) Subsequently, while passing between the grinding wheels 1 and 2, the upper and lower surfaces Wa and Wb are made up of a pair of surface grinding wheels 1a and 2a facing each other. After the grinding process, the work exit part B is subjected to a spark-out grinding process using the pre-grinding grinding wheel surface 6 and the lower surface grinding wheel surface 2a, and the final finish defined by these two grinding wheel surfaces 6, 2a. To dimensions Climb is it to become.
Other configurations and operations are the same as those in the first embodiment.

  In addition, Embodiment 1 and Embodiment 2 which were mentioned above show the suitable embodiment of this invention to the last, This invention is not limited to this, A various design change is possible in the range.

  For example, the specific shape and size of the grinding wheel surface 6 for the pre-grinding process of the upper grinding wheel 1 are not limited to those in the first or second embodiment, and depend on the shape and grinding conditions of the workpiece W to be ground. Various design changes can be made.

W Work (Workpiece)
Wa Upper surface of workpiece Wb Lower surface of workpiece Wc Work protrusion 1 Upper grinding wheel 1a Surface grinding wheel surface (flat grinding wheel surface) of upper grinding wheel
2 Lower grinding wheel 2a Surface grinding wheel surface of the lower grinding wheel (flat grinding wheel surface)
A Workpiece inlet part B Workpiece outlet part θ Inclination angle of the vertical grinding wheel RSa Workpiece allowance RSb Workpiece takeover allowance RSc Protrusion height allowance 3 Carrier device 4 Truing device 5 Control device (control means)
6 Wheel surface for pre-grinding process (chamfered part)
12 Carrier 13 Holding pocket 15 Discharge truing electrode

Claims (11)

A through-feed type double-head surface grinding method in which both surfaces of a workpiece are simultaneously ground while passing the workpiece between a pair of grinding wheels rotating with a flat grinding wheel surface facing each other,
By using a grinding wheel having a chamfered portion on the outermost peripheral portion of the flat grinding wheel surface as one grinding wheel of the pair of grinding wheels, this chamfered portion is located in front of the workpiece entrance portion of the pair of grinding wheels. While constituting the grinding wheel surface for the grinding process, the inclination angle of the flat grinding wheel surface in the pair of grinding wheels is set corresponding to the size of the machining allowance in the main grinding,
When passing the workpiece between the pair of grinding wheels, the workpiece is pre-ground by the pre-grinding process grinding wheel surface, and then the workpiece is ground by the pair of flat grinding wheel surfaces facing each other. A double-head surface grinding method characterized by the above. The cross-sectional shape dimension of the grinding wheel surface for the pre-grinding process in the grinding wheel is set according to the shape dimension of the part to be ground that is a target for the pre-grinding process in the workpiece. Double-head surface grinding method. The double-head surface grinding method according to claim 2, wherein the pre-grinding grinding wheel surface is a curved surface having an R-shaped cross-sectional contour that continues from the flat grinding wheel surface. The double-head surface grinding method according to claim 2, wherein the pre-grinding grinding wheel surface is a conical surface having a linear cross-sectional contour that continues to the flat grinding wheel surface. The grinding wheel portion forming the grinding wheel surface of the grinding wheel is constituted by a conductive grinding stone formed by bonding abrasive grains with a conductive binding material,
2. The double-head surface grinding method according to claim 1, wherein a flat grinding wheel surface and a pre-grinding grinding wheel surface of the grinding wheel are formed by electric discharge truing. When the discharge truing is performed, the grinding wheel is moved in the axial direction of the rotating shaft while moving the discharge truing electrode in a direction perpendicular to the rotating shaft of the grinding wheel. 6. A double-head surface grinding method according to claim 5, wherein a grinding wheel surface for the pre-grinding step is formed. A grinding device that simultaneously grinds both sides of a workpiece,
A pair of grinding wheels that are rotatably arranged opposite to each other and that have opposing flat grinding wheel surfaces;
Rotation driving means for rotating these grinding wheels,
A carrier having a plurality of holding pockets arranged to pass between the grinding wheel surfaces of the two grinding wheels and holding a workpiece;
Feed driving means for feeding and driving the carrier;
Control means for driving and controlling the rotation driving means and the feed driving means in conjunction with each other,
One grinding wheel of the pair of grinding wheels is in the form of a grinding wheel having a chamfered portion on the outermost peripheral portion of the flat grinding wheel surface,
The chamfered portion of the grinding wheel constitutes a grinding surface for a pre-grinding process at a work entrance portion of the pair of grinding wheels,
The double-head surface grinding apparatus, wherein the inclination angle of the flat grinding wheel surface in the pair of grinding wheels is set in accordance with the size of the machining allowance in the main grinding. The cross-sectional shape dimension of the grinding wheel surface for the pre-grinding process in the grinding wheel is set according to the shape dimension of the part to be ground that is a target for the pre-grinding process in the workpiece. Double-head surface grinding machine. The double-head surface grinding apparatus according to claim 8, wherein the pre-grinding process grindstone surface is a curved surface having an R-shaped cross-sectional contour that continues from the flat grindstone grindstone surface. The double-head surface grinding apparatus according to claim 8, wherein the pre-grinding grinding wheel surface is a conical surface having a linear cross-sectional contour that continues from the flat grinding wheel surface. The grinding wheel portion that forms the grinding wheel surface of the grinding wheel is composed of a conductive grinding wheel formed by bonding abrasive grains with a conductive binding material, and includes a discharge truing device that discharges the grinding wheel surface.
The double-head surface grinding apparatus according to claim 7, wherein a flat grinding wheel surface for grinding of the grinding wheel and a grinding wheel surface for a pre-grinding step are formed by the discharge truing device.

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