JP2947454B2 - Surface grinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface grinder,
More specifically, the present invention relates to a surface grinding machine that performs grinding by lowering a grindstone head from above and automatically bringing a rotatable grindstone into contact with a work clamped on a rotating worktable.

[0002]

2. Description of the Related Art Conventionally, in order to grind a certain amount based on the upper surface of a work with a grindstone that is rotatable with a surface grinder, first, a grindstone is applied to the work, and then the grinding amount, the cutting amount / times, etc. are determined. Either set and perform automatic grinding, or perform manual grinding while checking the scale.

[0003] It is very troublesome to first apply the whetstone to a work. Generally, the rotating grindstone is slowly approached to the work to stop the feed of the grindstone by watching the change of the grinding water or sparks, but it takes a long time and the grindstone is won. In addition, a change in the grinding water and sparks cannot be seen with the stopped grinding wheel, and the grinding wheel head is too heavy, so that the grinding wheel is crushed due to excessive feeding by a screw, etc., so that it is possible to win.

In order to solve the problem caused by the means for applying the grinding stone to the work, Japanese Patent Application Laid-Open No. Hei 4-217459 has already been proposed by the present applicant. In the grinding machine according to this publication, a main head including a grinding wheel shaft drive motor and a feed mechanism, and a processing portion including a grinding wheel, a grinding wheel shaft, and a bearing portion are separated from each other, and the weight of the processing portion is reduced by the weight of the main head. The working part is mounted on the main head in a semi-floating state by a spring, and a clamper that can firmly fix the working part to the main head is provided.

[0005]

By the way, in the above-mentioned conventional grinding machine, the main head and the processing portion are separated from each other, so that the main head and the processing portion are moved up and down with respect to the guide rail. A plurality of nuts must be used, and the main head nuts and the processed part nuts must be alternately arranged and mounted. Therefore, the grinding machine itself becomes large-scale and has a complicated configuration.

In addition, since the clamper is provided to integrate the main head and the processing section, the apparatus itself is complicated. In addition, the total weight of the main head and the processing part is too heavy for the self-weight grinding, and there is a problem in terms of safety.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the weight of a grinding wheel head and to simplify the structure in which the grinding wheel head is in a semi-floating state. In addition, the grinding wheel is pressed against a workpiece during grinding so as to improve safety. An object of the present invention is to provide a surface grinding machine which automatically performs self-weight grinding by setting the same weight as its maximum load, and furthermore, enables parallelism adjustment between a work table shaft and a grinding wheel shaft.

[0008]

In order to achieve the above object, a surface grinder according to the present invention is provided with an upright column extending vertically, and a table body fixed to this column is rotated through a bearing case via a bearing case. A work table mounted on a free spindle is provided with a workpiece to be ground mounted thereon, and a feed screw extending in a vertical direction connected to a feed drive motor fixed above the column is provided and screwed to the feed screw. A spring guide is provided on the feed nut via a spring biased upward, a piston fixed to the spring guide is provided, a cylinder equipped with the piston is provided, and a lower surface of the piston is fitted to the feed nut. The upper and lower stoppers are provided so as to be freely contactable with the upper surface of the combined upper and lower stoppers. A head is provided, a rotatable grindstone is provided on the grindstone head, and a work contact detection device for detecting that the grindstone has contacted the work is provided on the cylinder and a nut receiver for receiving the feed nut. It is assumed that.

In the surface grinding machine, a detection member for detecting the rotation of the work table is provided on the bearing case, and a detected member is provided on the spindle, and it is determined that the grinding wheel has come into contact with the work by the work contact detection device. After the detection, each time the worktable makes one rotation, the detected member crosses the inside of the detection member to detect that the worktable has made one rotation, and based on this detection result, the cutting amount of the grindstone with respect to the work is controlled. It is desirable to be configured.

[0010]

With the above-mentioned surface grinding machine, a work to be ground is mounted and fixed on a work table with a jig and a chuck. Next, after the grindstone head is in a semi-floating state, the grindstone head is lowered without rotating the grindstone, and the grindstone hits the work and stops. When the detection member and the detected member detect that the grindstone head has stopped, the grindstone is raised by an amount corresponding to the air cut.

Next, the grindstone is rotated and the semi-floating state of the grindstone head is released to start grinding. That is, the grinding wheel is lowered and the work table is rotated to grind the workpiece with the grindstone. When the grinding is completed, the grindstone head is returned to the original position, and the rotation of the grindstone and the worktable is stopped to perform a series of grinding processes. Ends.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

Referring to FIGS. 1, 2 and 3, the surface grinding machine 1 is provided with a Y-shaped support frame 3, which is mounted on the floor by, for example, three legs 5. Fixed. Moreover, on the support frame 3, a column 7, which is formed of a quadrangular prism-shaped pipe and extends in the vertical direction, is integrally provided upright.

A table body 9 is fixed with a plurality of bolts at the front part (left part in FIG. 2) of the column 7 in, for example, a height direction. A plurality of ribs 9A are integrally provided at the lower portion of the table main body 9 so as to extend downward. A drive motor 13 for rotating the table is attached to the ribs 9A via a motor bracket 11. .

A bearing case 15 is provided in the table body 9.
Is mounted and attached with a plurality of bolts. A spindle 19 is rotatably supported in the bearing case 15 via a plurality of bearings 17. A drive pulley 23 is fitted on the output shaft 21 of the drive motor 13, and a driven pulley 25 is fitted below the spindle 19. The driven pulley 25 and the driving pulley 23
, A belt 27 is wound. The spindle 1
A circular work table 29 is mounted on the upper part of the workpiece 9 so as to be freely clamped.

With the above configuration, when the drive motor 13 is driven, the drive pulley 23 is rotated via the output shaft 21. The rotation of the drive pulley 23 causes the spindle 19 to move through the belt 27 and the driven pulley 25 to rotate the spindle 19.
5 will be rotated. This spindle 19
The work table 29 is rotated by the rotation of.

As shown in FIG. 1, for example, a magnetic chuck 31 is detachably provided on the work table 29, and a shear angle punch is clamped as a work W to be ground via a jig 33. The work table 29 has a jig 31 as shown in FIG.
Are detachably provided, and a punch is clamped as a work W to be ground. Therefore, by rotating the work table 29, the work W is rotated in the same direction via the magnetic chuck 31 and the jig 33.

A bracket 35 is attached to the column 7 with bolts. The bracket 35 is attached to the front of the column 7 by bolts on the side of the lower frame 39 surrounding the table body 9 and the like.

A pump 41 is provided on the bracket 35, and a grinding water tank 43 containing grinding water is disposed in the lower frame 39. The grinding water tank 43 and the pump 41 are connected by a pipe 45. A collecting joint 47 for collecting the grinding water used in the grinding process is provided on the left side of the table body 9 in FIG. 1, and one end of a collecting pipe 49 is connected to the collecting joint 47. And the other end of the collection pipe 49 is connected to the grinding water tank 4.
3 is communicated.

An upper frame 51 is provided above the lower frame 39, and the upper frame 51 is attached to the column 7. A guide rail 53 extending in the up-down direction is laid on the column 7 (the left side in FIG. 2) in the upper frame 51, and the guide rail 53 is provided with a plurality of guide members 55 via the grindstone head 5.
7 is provided movably in the vertical direction.

A drive motor 61 for rotating the grinding wheel is mounted on the top of the grinding wheel head 57 via a motor flange 59. A spindle 65 is rotatably supported in the grindstone head 57 via a plurality of bearings 63. The spindle 65 is integrated with an output shaft 67 of the grindstone rotation drive motor 61 by a key or the like. .
Below the spindle 65, for example, a CBN grinding stone 69
Is attached with a plurality of bolts.

With the above configuration, the drive motor 6 for rotating the grinding wheel
1 is driven, the spindle 6 is driven via the output shaft 67.
5 is rotated with respect to the grindstone head 57. The rotation of the spindle 65 causes the grindstone 69 to rotate in the same direction via the grindstone mounting cup 71.

Referring also to FIG. 4, a support block 73 is mounted with a plurality of bolts on the upper part (the upper part on the left side in FIG. 2) inside the front part of the column 7.
A motor bracket 75 is attached to the support block 73 with a plurality of bolts, and the motor bracket 75 is provided with a feed drive motor 77.

A drive pulley 81 is fitted on the output shaft 79 of the feed drive motor 77. 4, a bearing case 83 is attached to the upper left portion of the column 7 with bolts, and a trapezoidal screw 87 as a feed screw extending in the vertical direction via a plurality of bearings 85 is provided in the bearing case 83. It is rotatably supported. A driven pulley 89 is fixed to the upper part of the trapezoidal screw 87 with several set screws. A belt 91 is wound around the driven pulley 89 and the driving pulley 81.

With the above configuration, when the feed drive motor 77 is driven, the drive pulley 81 is rotated via the output shaft 79. The rotation of the driving pulley 81 is controlled by the belt 9.
1, The trapezoidal screw 87 is rotated via the driven pulley 89.

As shown in FIG. 4, a feed nut 93 is screwed into the trapezoidal screw 87. A spring 9 urged upward is provided on the feed nut 93.
A spring guide 97 is provided through the center 5. A female screw 103 formed on an upper inner peripheral portion of a piston 101 is screwed into a male screw 99 formed on an upper outer peripheral portion of the spring guide 97 and a lock nut 105.
Locked in. The piston 101 is mounted on a cylinder 107 integrated with the grinding head 57. Further, the lower surface of the piston 101 is
The upper and lower stoppers 109 are fitted to the upper surface of the upper and lower stoppers 109 so as to be freely contactable.

The feed nut 93 is connected to the feed nut receiver 11.
One is attached with a plurality of bolts. Further, the left side of the cylinder 107 integrated with the grindstone head 57 in FIG.
13 and the limit switch 113
Corresponding to the above, a dog 115 of the work contact detection device is attached to the feed nut receiver 111. The feed nut 93 is prevented from rotating by the rotation preventing pin 117 and the ball bush 119 so that the feed nut 93 does not rotate. A cylinder chamber 121 is provided above the piston 101.
The cylinder frame 123 is provided in order to form. This cylinder frame 123 has an air passage 1
One end of the air passage 125 is communicated with the cylinder chamber 121 and the air passage 125 is formed.
Is connected to an air source (not shown).

With the above configuration, when air having an air pressure of, for example, 4.5 kg / cm ² from arrow X in FIG. 4 is supplied to the cylinder chamber 121 through the air passage 125, the piston 101 resists the urging force of the spring 95. The piston 101 descends and the lower surface of the piston 101 comes into contact with the upper surface of the upper / lower stopper 109, so that the grindstone head 57 is held in a semi-floating state as shown in FIG. For example, the weight of the grindstone head 57 is 45 kg, and the thrust of the piston 101 is π
(5 ² -3 ²⁾ and × 4.5 / 4 = 56.5kgf, further when the biasing force of the spring 95 and 41 kg, the pressure between the lower surface of the upper surface and the upper and lower stopper 109 of the spring receiver 111 is 4 kg (= 45- 41), and the pressure between the upper surface of the vertical stopper 109 and the lower surface of the piston 101 is reduced to 15.5 kg (= 56.5-45).

Referring to FIGS. 2 and 5, a joint 127 is connected to the pump 41, and a manual ball valve 129 is mounted on the left side of the motor bracket 59 in FIGS. The joint 131 is attached to the ball valve 129. One end of a pipe 133 is connected to the joint 131, and the other end of the pipe 133 is connected to a joint 127 attached to the pump 41. In FIG. 5, a grinding water passage 135 through which grinding water passes is formed in the grindstone head 57, and several injection holes 137 are provided on the lower surface of the grinding water passage 135. On the left side of the injection port 137, a cover 139 for preventing the scattering of grinding water is provided.

With the above configuration, when the pump 41 is operated, the grinding water is sent from the tank 43 to the grinding water passage 135 via the pipes 45 and 133 and the ball valve 129. The grinding water sent to the grinding water passage 135 is appropriately squeezed by the ball valve 129, and the grinding water is sprayed from the injection port 137 toward the workpiece W to be ground during the grinding process. Further, the grinding water used for the grinding is collected in the tank 43 through the collection pipe 49 as shown in FIG.

As shown in FIG. 6, a bracket 141 is attached to a lower portion of the bearing case 15 with a plurality of bolts, and the bracket 141 is provided when the work table 29 makes one rotation. A photoelectric sensor 143 is provided as a detection member for detecting rotation. On the other hand, a pulley fixing ring 145 is attached to the lower portion of the spindle 19, and a detection piece 147 as a member to be detected is attached to the pulley fixing ring 145.

With the above configuration, when the spindle 19 is rotated, the work table 29 is rotated and the detection piece 147 is rotated. The detection piece 147 crosses the inside of the photoelectric sensor 143 every time the work table 29 makes one rotation, thereby detecting that the work table 29 has made one rotation.

In FIG. 1, a control device 147 is provided on the left front surface of the upper frame 51, and the surface grinder 1 is automatically controlled by the control device 147. In FIG. 2, the upper surface on the right side of the lower frame 39 has the same function as the prevention cover 149 for preventing the scattering of the grinding water injected from the injection port 137 and the prevention cover 149 extending in the vertical direction on the grinding wheel head 57. A protective cover 151 is provided.

Referring to FIG. 2, FIG. 7 and FIG. 8, an air passage 153 extending vertically is formed at the axis of the spindle 19, and a rotary joint 155 is provided below the air passage 153. , And a pipe 157 are connected to an air source (not shown). The air passage 153
Has a leading end that communicates with a lower portion of the piston 158 that is in contact with the lower surface of the work table 29. This piston 158 is O
Sealed with ring 158A. The work table 29 has a spring 1 with respect to the spindle 19.
For example, eight bolts 161 with 59 are radially attached.

With the above structure, the work table 2 is compressed by the compression force of the spring 159 interposed between the bolts 161.
The work table 9 is clamped by the spindle 19 and supplies air from an air source (not shown) to the air passage 153 through the pipe 157 and the joint 155, thereby pressing the work table 29 against the compressive force of the spring 159 by the pressure of the air.
To be unclamped.

In FIG. 8, a flange 29F is provided on the inner periphery of the work table 29 every 120 degrees, and a flange 31T is provided on the outer periphery of the jig 31 every 120 degrees.
Is provided. Moreover, a stopper pin 162 for stopping the jig 31 is provided on the work table 29.

With the above configuration, when the jig 31 is rotated clockwise by 60 degrees in FIG. 8, the jig 31 hits the stopper pin 162 and stops. When the flange 31T is disengaged from the flange 29F and pulled upward to be unclamped, and the jig 31 is turned 60 degrees counterclockwise, it hits the stopper pin 162 and stops. The flange 31T overlaps the flange 29F and is clamped.

In the above configuration, the work table 29
Then, the work W to be ground is mounted and fixed by the jig 31 and the chuck 33. As shown in FIG. 4, the grindstone head 57 is brought into a semi-floating state. In this state, when the trapezoidal screw 87 is rotated to lower the feed nut 93, the grindstone head 57 is lowered with respect to the guide rail 53.
When the grindstone head 57 descends, the pressure between the upper surface of the feed nut receiver 111 and the lower surface of the upper and lower stoppers 109 becomes a negative frictional resistance of the grindstone head 57, for example, 4 kg-45 kg ×
Although it is reduced to about 0.05 = 1.75 kg, there is no gap.

When the grindstone 69 comes into contact with the workpiece W, the grindstone head 57 stops and the feed nut 93 continues to descend, so that a gap is formed between the upper surface of the feed nut 111 and the lower surface of the upper and lower stopper 109. That is, since the feed nut 93, the feed nut receiver 111 and the dog 115 are integrated, the dog 115 is lowered together and the dog 115 is separated from the limit switch 113, for example, the upper surface of the feed nut receiver 111 and the upper and lower stoppers 109.
The limit switch 113 operates when the gap between the lower surfaces becomes 0.1 ^mm .

The feed (lowering) of the grinding wheel head 57 is decelerated and stopped by the signal of the operation of the limit switch 113, and the number of pulses of the feed drive motor 77 (pulse motor) is counted and controlled from the signal of the operation of the limit switch 113. . For example, if the feed is 0.0005 ^mm per pulse, deceleration can be stopped in 20 pulses, and the time is 0.0
06 ^sec , the overrun amount is about 0.01 ^mm .

The feed nut 93 is, for example, 0.11
After I stopped by ^mm overrun, when the air cut portion of the grinding process for example 0.15 ^mm, a trapezoidal screw 87 rotated reversely to put 0.15 ^mm per gap grindstone 69 from the workpiece W 0.26 ^mm (= 0.11 + 0.15) When raised, the grindstone 69 is rotated and grinding water is injected to release the semi-floating state, and the worktable 29 is further rotated to start cutting.

After the start of cutting, grinding is performed for a grinding allowance plus an air cut. Then, the cutting process is performed by cutting the cutting amount / times for each rotation signal of the work table 29. O grinding is performed to prevent uncut portions and to improve surface roughness. Since one signal is obtained in one rotation of the work table 29, the cutting is performed once per rotation of the work, and the cutting amount is accurately controlled.

At the end of the O-grinding, the injection of the grinding water is stopped, and the grindstone 69 is raised while shaking off the grinding water.
Contacts the photoelectric switch 177 to decelerate and stop (see FIG. 4). By stopping the rotation of the grindstone 69 and stopping the rotation of the work table 29, a series of grinding processes is completed.

Therefore, after the grindstone head 57 is in a semi-floating state, the grindstone head 57 is lowered in this state to
Hits the work W, the grindstone head 57 stops once, and the origin position is set. That is, the limit switch 113 contacts the dog 115 and is sensed.

After the grindstone head 57 is raised from the upper surface of the work W by the amount of air cut, the amount of rise of the grindstone 69 from this origin position is 0.1 ^mm between the stoppers, the overrun amount is 0.01 ^mm, and the air cut Although the total is 0.26 ^{mm for} 0.15 ^mm , the gap is 0.1 ^mm and the overrun amount is 0.
Since the difference is 01 ^mm, there is a machine difference, so it is necessary to correct the grinding.) The semi-floating state is released, and the grindstone head 57 is lowered while rotating the grindstone 69 and the work table 29, and the work W is weighted by the grindstone head 57 by the grindstone 69. By performing the self-weight grinding, automatic grinding can be performed regardless of the height of the work.

In this embodiment, a 45 kg heavy grinding wheel head 5 is used.
7 moves downward at a speed of 170 ^{mm 2} / min in a semi-floating state, and the grindstone 69 hits the work W, a force of 8 kgf is applied between the grindstone 69 and the work W, and the whole machine is bent by the force. Although a bending of about 0.003 ^mm occurs between W, the whetstone 69 is lifted after the stop, so that it does not become an error factor. Therefore, highly accurate grinding can be performed.

Since the grindstone head 57 rides on the feed nut 93, a force greater than the weight of the grindstone head 57 (for example, 45 kg) is not applied between the grindstone 69 and the work W, so that the safety is high.

Since the cut into the work W is controlled by the grindstone 69 for each signal of each rotation of the work, if the work table 29 stops due to some trouble, the cut signal is not output and the cut is stopped. high.

The spindle 6 which is the grinding wheel shaft of the grinding wheel 69
9, 10, and 11, the upper surface of the table body 9 and the bearing case 15 are adjusted in order to adjust the parallelism between the spindle 5, which is the table shaft of the work table 29, and the work table 29.
For example, three spaced spacers 163 are provided at equal intervals on the outer peripheral portion between the lower surface of the table body 9 and the table body 9 and the bearing case 15 are mounted with three bolts 165 through these holes. . Further, the table body 9 is attached to the column 7 with a plurality of (seven in this embodiment) bolts 167 in a direction parallel to the paper surface of FIG. Similarly, a plurality of (one in this embodiment) bolts 169 are attached to the lower central portion.

In FIG. 11, the upper and lower left and right bolts 167 of the table body 9 are connected to six adjusting screws 17.
1 and the bolt 169 is adjusted with the adjusting screw 173.
Is to be adjusted.

With the above configuration, the left and right adjustment is performed by pushing the bolt 169 with the six adjustment screws 171. If the deviation from the front and rear exceeds 0.01 ^mm , the spacer 163 is rounded up to within 0.01 ^mm . And 0.01
The front-back adjustment within ^mm is adjusted by bending the table main body 9 by pushing and pulling adjustment with a bolt 169 and an adjusting screw 173. After the adjustment, the adjusting screw 171 is loosened and the bolt 169 and the adjusting screw 173 are not strongly tightened to reduce the distortion stress at the time of the adjustment.
Deterioration due to the passage of time can be prevented. The parallelism adjustment can be easily performed by using the left and right and front and rear separate methods as described above.

The present invention is not limited to the above-described embodiment, but can be embodied in other modes by making appropriate changes. In the above embodiment, spacer 1
Although an example in which three 63s are provided has been described, when distortion is symmetrical, four spacers 163 may be provided.

[0053]

As will be understood from the above description of the embodiment, according to the present invention, after the grinding wheel head is in a semi-floating state, the grinding wheel head is lowered in this state, and the grinding wheel once hits the workpiece. The grindstone head is stopped by sensing the detecting member and the detected member, and the origin position is set. After the travel distance (for example, about 0.1 ^mm ) from when the grindstone head hits the work to the work from the origin position until it is sensed, the deceleration overrun distance (for example, 0.003 ^mm ) after sensing, and after raising the air cut, By lowering the grindstone head while rotating the grindstone and the work table and grinding the work with the grindstone by its own weight, the grinding can be performed automatically irrespective of the height of the work.

When the grindstone head descends in a semi-floating state and the grindstone hits the work, only a small force is applied between the grindstone and the work, but the machine bends even with the slight force. Then, by lifting the grindstone from the work by the amount of air cut, this deflection is removed and the machine is returned to normal to start grinding, so that high-precision grinding can be performed.

In the embodiment, since the grinding wheel shaft is driven at 2.2 kg and the grinding wheel diameter is 150 ^mm , the grinding wheel head requires a maximum force of about 45 kgf for pressing the grinding wheel against the work during grinding. . Since this weight is cut on the feed nut, no more force is applied between the grindstone and the work than the weight of the grindstone head. If the depth of cut is increased beyond the capability of the grinding wheel due to its own weight grinding, uncut portions will occur. When the uncut portion reaches 0.1 ^mm , the grinding wheel head rises 0.1 ^mm from the nut, the limit switch is activated, and the machine stops. If the uncut amount is small, there is a possibility that the grinding can be performed at the time of 0 grinding. Therefore, the safety can be improved and the life of the grindstone can be extended.

Since the cut into the work is controlled by the grindstone at every rotation signal of the work, if the work table stops due to some trouble, the cut stops, so there is no problem in terms of safety.

[0057]

[Brief description of the drawings]

FIG. 1 is a front sectional view of a surface grinder according to an embodiment of the present invention.

FIG. 2 is a right side sectional view of FIG.

FIG. 3 is a plan view of FIG.

FIG. 4 is an enlarged cross-sectional view taken along the line IV in FIG. 1;

FIG. 5 is an enlarged view of a portion viewed from an arrow V in FIG. 2;

FIG. 6 is an enlarged view of a part viewed from the arrow VI in FIG. 2;

FIG. 7 is an enlarged view of a part viewed from an arrow VII in FIG. 2;

FIG. 8 is a plan view of only a work table.

FIG. 9 is an enlarged front view of a state where the work body is attached to a column.

FIG. 10 is a view taken along line XX in FIG. 9;

FIG. 11 is a right side view in FIG. 9;

[Explanation of symbols]

 Reference Signs List 1 surface grinder 7 column 9 table body 15 bearing case 19 spindle 29 work table 31 jig 57 grindstone head 69 grindstone 87 ball screw (feed screw) 93 feed nut 95 spring 97 spring guide 101 piston 107 cylinder 109 vertical stopper 111 feed nut received

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B24B 7/04 B24B 41/04-41/053 B24B 47/20-47/22

Claims (2)

(57) [Claims] 1. A vertically extending column (7) is erected, and a spindle (1) that can freely rotate through a bearing case (15) is mounted on a table body (9) fixed to the column (7).
A work table (29) mounted on 9) and holding a work (W) to be ground is provided, and a vertically extending feed connected to a feed drive motor (77) fixed above the column (7). A screw (87) is provided.
A spring guide (9) is applied via a spring (95) urged upward onto a feed nut (93) screwed into the nut 7).
7), and a piston (101) fixed to the spring guide (97) is provided.
Is provided, the lower surface of the piston (101) is provided so as to be able to abut on the upper surface of an upper and lower stopper (109) fitted to the feed nut (93), and the upper portion is provided on the cylinder (107). And a grindstone head (57) whose lower part is provided on an upper and lower stopper (109). A rotatable grindstone (69) is provided on the grindstone head (57). And a nut receiver (111) for receiving the feed nut (93) is provided with a work contact detection device (113, 115) for detecting that the grinding stone (69) has contacted the work (W). Surface grinding machine. 2. A detection member (143) for detecting rotation of a work table (29) is provided on the bearing case (15), and a detection member (14) is provided on the spindle (19).
7), and the work contact detection device (113, 11) is provided.
After detecting that the grindstone (69) has contacted the work (W) in 5), the detected member (147) crosses the inside of the detection member (143) every time the work table (29) makes one rotation. 2. The apparatus according to claim 1, wherein the table is configured to detect that the table has rotated once, and to control a cutting amount of the grindstone with respect to the workpiece based on the detection result. Surface grinder.