JP2014213390A - Grinder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grinder in which oil supplied to a shaft bearing of a grind stone shaft member can be cooled quickly.SOLUTION: Since the inside surface of a grind stone cover 48 is sufficiently cooled by grinding liquid C and air B corotationally-rotated by rotation of a grind stone wheel 43 around an outer peripheral surface 43a of the grind stone wheel 43, oil D flowing in a channel 84 mounted at the grind stone cover 48 can be cooled quickly, too. Thus, thermal displacement due to heat transmission of the oil D at the portion relating to grinding can be suppressed, and highly accurate grinding can be performed. Since burden of a device for cooling the oil D can be reduced, an effect of energy saving can be obtained.

Description

  The present invention relates to a grinding machine for rotating a grinding wheel relative to an object to be ground and grinding the object to be ground with the grinding wheel while supplying a grinding liquid toward a contact portion between the object to be ground and the grinding wheel. Is.

  For example, in Patent Document 1, the grinding wheel is moved with respect to the object to be ground while rotating the grinding wheel, and the grinding object is ground with the grinding wheel while supplying the grinding liquid toward the contact portion between the grinding object and the grinding wheel. A grinding machine is described. The grinding wheel is covered with a grinding wheel cover to prevent scattering of the grinding fluid. The grinding wheel shaft member of the grinding wheel is supported by a hydrostatic bearing in order to rotate at high speed and high accuracy. This hydrostatic bearing uses oil as a working fluid.

JP 2010-269411 A

  The oil supplied to the hydrostatic bearing of the grindstone shaft member rises in temperature (about 10 degrees or so) due to shear heat generation accompanying high-speed rotation of the grindstone shaft member. The oil whose temperature has risen is returned to a tank for storing the oil through a path for discharging the oil. And it cools to fixed temperature with an oil cooler etc., and is again supplied to the hydrostatic bearing of a grindstone shaft member. For this reason, the heat of oil may be transmitted from the path | route which discharges oil to the site | part which concerns on grinding, and there exists a possibility that a thermal displacement may arise in the said site | part and have a bad influence on grinding.

  This invention is made | formed in view of such a situation, and it aims at providing the grinding machine which can cool rapidly the liquid supplied to the liquid bearing of the grindstone shaft member.

  (Claim 1) A grinding machine according to this means includes a grinding wheel that grinds an object to be ground while rotating, a liquid bearing that rotatably supports the grinding wheel, and a tank that stores liquid to be supplied to the liquid bearing. A grinding fluid supply device for supplying a grinding fluid toward a contact portion of the grinding wheel with the object to be ground, and for covering the grinding wheel and returning the liquid discharged from the liquid bearing to the tank. And a grindstone cover provided therein.

(Claim 2) Further, the flow path is formed so as to pass through a portion sandwiched between a portion of the inner surface of the grindstone cover facing the outer peripheral surface of the grinding wheel and an outer surface of the grindstone cover. You may do it.
(Claim 3) Further, a liquid reservoir for temporarily retaining the liquid may be formed inside the grindstone cover.
(Claim 4) Moreover, you may make it the inner peripheral surface of the said liquid reservoir part be formed in the shape along the inner surface facing the outer peripheral surface of the said grinding wheel in the said grindstone cover.

(Claim 5) In addition, air from an air seal that seals the grinding wheel shaft member of the grinding wheel with air may be supplied to the flow path.
(Claim 6) Further, a grinding wheel base on which the grinding wheel is arranged may be provided with a path leading from the flow path to the tank.

  (Claim 1) According to the present invention, the inner side surface of the grinding wheel cover is sufficiently cooled by the grinding liquid that is rotated along the outer peripheral surface of the grinding wheel as the grinding wheel rotates. The liquid flowing in the flow path can also be quickly cooled. Thereby, the thermal displacement by the heat transfer of the liquid in the site | part in connection with grinding can be suppressed, and highly accurate grinding can be performed. Moreover, since the burden of the apparatus for cooling the liquid can be reduced, an energy saving effect can be obtained.

(Claim 2) As a result, the inner surface near the flow path in the grindstone cover is sufficiently supplied with the grinding liquid rotated along the outer peripheral surface of the grindstone, so that the liquid flowing in the flow path can be cooled more quickly. can do.
(Claim 3) Thereby, since the liquid is once retained in the liquid reservoir, the liquid can be further cooled.

(Claim 4) Thereby, the liquid once retained in the liquid reservoir is sufficiently cooled by the grinding fluid flowing on the inner surface of the grinding wheel cover opposite to the outer peripheral surface of the grinding wheel.
(Claim 5) As a result, a force in the discharge direction is applied to the liquid flowing in the flow path, so that the liquid flowing in the flow path can be smoothly returned to the tank and the liquid in the flow path can be recirculated. Backflow can be prevented.
(Claim 6) Thereby, a compact design is possible even if a liquid flow path is provided in the grindstone cover.

FIG. 2 is a plan view of a grinding machine according to an embodiment of the present invention. FIG. 2B is a sectional view taken along line BB in FIG. FIG. 2B is a sectional view taken along line AA in FIG. It is sectional drawing which shows the grinding wheel periphery including an oil flow path and a path | route. It is a figure for demonstrating the cooling effect | action of the oil in the flow path and path | route of an oil. It is a figure which shows the 1st modification of the flow path of oil. It is a figure which shows the 2nd modification of the flow path of oil. It is a figure which shows the 3rd modification of the flow path of oil.

(1. Machine configuration of grinding machine)
Hereinafter, a grinding machine according to an embodiment of the present invention will be described with reference to the drawings. As an example of the grinding machine of the present embodiment, a grinding wheel traverse type cylindrical grinding machine capable of grinding a shaft-like workpiece will be described as an example. The traverse direction is the Z-axis direction, the horizontal direction perpendicular to the traverse direction is the X-axis direction, and the vertical direction perpendicular to the traverse direction is the Y-axis direction.

As shown in FIG. 1, the grinding machine 1 includes a bed 10, a headstock 20, a tailstock 30, a grindstone support device 40, a coolant (grinding fluid) supply device 50, a sizing device 60, and a control. And the device 70 and the like.
The bed 10 has a substantially rectangular shape and is disposed on the floor. However, the shape of the bed 10 is not limited to a rectangular shape. On the upper surface of the bed 10, a pair of Z-axis guide rails 11 a and 11 b for a grindstone table, on which a grindstone table traverse base 41 constituting the grindstone support device 40 can slide, extend in the Z-axis direction and mutually. Is fixed parallel to

  Further, between the pair of grinding wheel base Z-axis guide rails 11a and 11b on the upper surface of the bed 10, a grinding wheel base Z-axis ball screw 11c for driving the grinding wheel base traverse base 41 in the Z-axis direction is disposed. A grinding wheel base Z-axis motor 11d that rotationally drives the grinding wheel base Z-axis ball screw 11c is disposed and fixed.

  The head stock 20 includes a head stock main body 21, a main shaft 22, a main shaft motor 23, a main shaft center 24, and the like. A main shaft 22 is rotatably inserted into and supported by the head stock main body 21. The headstock main body 21 is fixed to the upper surface of the bed 10 so that the axial direction of the main spindle 22 faces the Z-axis direction and is parallel to the pair of Z-axis guide rails 11a and 11b for the grindstone head.

  A spindle motor 23 is provided at the left end of the spindle 22, and the spindle 22 is rotationally driven around the Z axis with respect to the spindle head body 21 by the spindle motor 23. The spindle motor 23 is provided with an encoder capable of detecting the rotation angle of the spindle motor 23. A spindle center 24 that supports one axial end of the shaft-shaped workpiece W is attached to the right end of the spindle 22.

The tailstock 30 includes a tailstock main body 31, a tailstock center 32, and the like. A tailstock center 32 is rotatably inserted into and supported by the tailstock body 31. The tailstock main body 31 is fixed to the upper surface of the bed 10 so that the axial direction of the tailstock center 32 faces the Z-axis direction and the rotational axis of the tailstock center 32 is coaxial with the rotational axis of the main shaft 22. ing.
That is, the tailstock center 32 is arranged so as to be rotatable about the Z axis while supporting both ends of the spindle center 24 and the workpiece W in the axial direction. The tailstock center 32 is configured such that the amount of protrusion from the right end surface of the tailstock body 31 can be changed according to the length of the workpiece W.

  The grinding wheel support device 40 includes a grinding wheel base traverse base 41, a grinding wheel base 42, a grinding wheel 43, a grinding wheel rotating motor 44, and the like. The grinding wheel base traverse base 41 is formed in a rectangular flat plate shape, and is slidably disposed on the pair of grinding wheel base Z-axis guide rails 11 a and 11 b on the upper surface of the bed 10.

  The grinding wheel base traverse base 41 is connected to a nut member of the grinding wheel base Z-axis ball screw 11c, and is moved along the pair of grinding wheel base Z-axis guide rails 11a and 11b by driving the grinding wheel base Z-axis motor 11d. Is done. The wheel head Z-axis motor 11d is provided with an encoder capable of detecting the rotation angle of the wheel head Z-axis motor 11d.

A pair of X-axis guide rails 41a and 41b for the grindstone table, on which the grindstone table 42 can slide, are arranged and fixed in parallel to each other on the upper surface of the traverse base 41. Yes.
Further, between the pair of grinding wheel table X-axis guide rails 41a and 41b on the upper surface of the grinding wheel table traverse base 41, a grinding wheel table X-axis ball screw 41c for driving the grinding wheel table 42 in the X-axis direction is disposed. An X-axis motor 41d for the grindstone for rotating the X-axis ball screw 41c for the grindstone is disposed. The wheel head X-axis motor 41d is provided with an encoder capable of detecting the rotation angle of the wheel head X-axis motor 41d.

The grinding wheel base 42 is slidably disposed on a pair of grinding wheel base X-axis guide rails 41 a and 41 b on the upper surface of the grinding wheel base traverse base 41. The grinding wheel base 42 is connected to the nut member of the grinding wheel base X-axis ball screw 41c, and is moved along the pair of grinding wheel base X-axis guide rails 41a and 41b by driving the grinding wheel base X-axis motor 41d. .
That is, the grindstone base 42 is configured to be movable relative to the bed 10, the headstock 20 and the tailstock 30 in the X-axis direction (plunge feed direction) and the Z-axis direction (traverse feed direction).

  A grindstone shaft member 45 is supported on the upper surface of the grindstone table 42 by a hydrostatic bearing 47 (corresponding to the “liquid bearing” of the present invention) so as to be rotatable around the Z axis. In the hydrostatic bearing 47, oil (corresponding to “liquid” of the present invention) stored in the tank 81 accommodated in the bed 10 passes through a pipe from a pump 82 attached to the tank 81, and the bearing housing 49 is supplied through a supply oil passage 83a (see FIG. 2A) provided at an upper portion in 49.

  The grindstone shaft member 45 is provided with an air seal portion 46 (see FIG. 2A) for preventing the coolant (grinding fluid) from entering the coolant supply device 50. A disc-shaped grinding wheel 43 is coaxially attached to one end of the grinding wheel shaft member 45.

  A grindstone rotating motor 44 for rotating the grindstone shaft member 45 together with the grinding wheel 43 via a belt / pulley mechanism 46 is fixed to the upper surface of the grindstone table 42. On the side surface in the Z-axis direction of the grindstone table 42, a grindstone is provided to prevent scattering of coolant supplied from the coolant supply device 50 to the contact portion between the outer circumferential surface 43 a of the grinding wheel 43 and the outer circumferential surface Wa of the workpiece W. A grindstone cover 48 covering the vehicle 43 is attached.

  As will be described in detail later, as shown in FIG. 2A, the temperature rising oil discharged from the hydrostatic bearing 47 through the discharge oil passage 83b provided in the lower portion of the bearing housing 49 is contained in the grindstone cover 48. A flow path 84 for cooling and returning to the tank 81 is provided. In addition, an air introduction pipe portion 46 a for introducing air from an air seal portion 46 provided in the hydrostatic bearing 47 is communicated with the discharge oil passage 83 b.

  Further, as shown in FIG. 2B, a path 85 connected from the flow path 84 to the tank 81 is provided on the back surface 48a of the grindstone cover 48 (the surface opposite to the workpiece W side in the X-axis direction). . Thus, by providing the oil path 85 on the back surface 48 a of the grindstone cover 48, a compact design is possible even if the oil passage 84 is provided in the grindstone cover 48.

  The coolant supply device 50 includes a coolant storage tank 51, a pump 52, a coolant supply nozzle 53, and the like. The coolant storage tank 51 and the pump 52 are installed beside the bed 10. The coolant supply nozzle 53 is attached to the grinding wheel cover 48 above the grinding wheel 43 and connected to the pump 52 by piping.

The sizing device 60 is a device for measuring the outer diameter of the workpiece W at the grinding site and outputting a measurement signal to the control device 70.
The control device 70 controls each motor to rotate the workpiece W and the grinding wheel 43 about the Z axis, and relative to the workpiece W in the Z axis direction and the X axis direction of the grinding wheel 43. It is an apparatus which grinds the outer peripheral surface of the workpiece W by changing the position.

(2. Oil flow paths and paths)
Next, the detailed structure of the flow path 84 and the path 85 for cooling the oil discharged from the hydrostatic bearing 47 and returning it to the tank 81 will be described.

  As shown in FIGS. 2A and 2B, the flow path 84 includes an introduction pipe portion 84a formed in a tubular shape extending in the Z-axis direction from the side surface 48b (the surface on the bearing housing 49 side) of the grindstone cover 48 inside the grindstone cover 48; An oil reservoir 84b (corresponding to a “liquid reservoir” of the present invention) in which the side view in the Z-axis direction extends in a substantially triangular shape downward from the introduction pipe portion 84a to the inside of the grindstone cover 48, and the oil reservoir 84b The lead-out pipe portion 84c is formed in a tubular shape penetrating the back surface 48a of the grindstone cover 48 in the lower part.

  The introduction pipe portion 84a of the flow path 84 is communicated with a discharge oil passage 83b provided at a lower portion in the bearing housing 49, and introduces oil flowing from the discharge oil passage 83b into the oil reservoir portion 84b. In the oil reservoir portion 84b of the flow path 84, the oil introduced from the introduction pipe portion 84a is temporarily retained. The outlet pipe portion 84c of the flow path 84 communicates with a path 85 connected to the tank 81, and guides the oil once retained in the oil reservoir 84b to the path 85.

  The flow path 84 is an interior 48A (FIG. 2B) sandwiched between a portion of the inner surface 48d of the grinding wheel cover 48 that faces the outer peripheral surface 43a of the grinding wheel 43 and the outer surface (the rear surface 48a, the bottom surface 48c, and the upper surface 48e) of the grinding wheel cover 48. It is formed so as to pass through the hatched portion shown in FIG. That is, the introduction pipe portion 84a, the oil reservoir portion 84b, and the lead-out tube portion 84c are formed in the interior 48A. Of the inner peripheral surface of the oil reservoir 84 b, the inner peripheral surface 84 ba on the outer peripheral surface 43 a side of the grinding wheel 43 is formed in an arc shape along the inner side surface 48 d facing the outer peripheral surface 43 a of the grinding wheel 43 in the grinding wheel cover 48. Has been.

  As shown in FIG. 3, the path 85 is connected to the outlet pipe portion 84 c of the flow path 84 and is connected to the back surface 48 a of the grindstone cover 48 and extends in the X-axis direction, and the drain pipe 85 a As shown in FIG. 1, it is configured by a tubular toy 85b that extends in the X-axis direction and is fitted to the side surface of the grindstone base traverse base 41 so as to be slidable in the axial direction.

  When the grindstone table 42 moves in the X-axis direction, the drain pipe 85a expands and contracts with respect to the toy 85b to absorb the movement of the grindstone table 42 in the X-axis direction. The fitting portion between the drain pipe 85a and the toy 85b is sealed by a mechanical seal 85c in order to prevent oil leakage and entry of dust from the outside. In order to reduce the sliding resistance as much as possible with an emphasis on processing accuracy, an air seal in which the drain pipe 85a and the toy 85b are not in contact with each other may be used.

  Next, the reason why the flow path 84 is provided inside the grindstone cover 48 will be described. Here, in grinding by the grinding machine 1, a large amount of coolant is supplied from the coolant supply device 50 in order to prevent deterioration of the quality of the ground surface such as grinding burn of the workpiece W.

  That is, as shown in FIG. 4, the coolant C in the coolant storage tank 51 is fed from the pump 52 to the coolant supply nozzle 53, and is ground to the outer peripheral surface 43 a of the grinding wheel 43 from the supply port 53 a of the coolant supply nozzle 53. It is supplied toward the contact portion T with the outer peripheral surface Wa of the object W.

  A part of the supplied coolant C is applied to the contact part T to cool the contact part T, and the remaining coolant C is rotated around the outer peripheral surface 43 a of the grinding wheel 43 and applied to the inner surface of the grinding wheel cover 48. Then, the coolant C flows down below the bed 10 and is returned to the coolant storage tank 51 after the chips are separated by a magnet separator (not shown).

  The coolant C fed to the coolant supply nozzle 53 is controlled to a constant temperature, like the oil D supplied to the hydrostatic bearing 47. Therefore, the grindstone cover 48 to which the coolant C is applied is also at the same temperature as the coolant C. Since the grindstone cover 48 is disposed in the vicinity of the hydrostatic bearing 47, the grindstone cover 48 is discharged from the hydrostatic bearing 47 by providing it inside the grindstone cover 48 so as to communicate with the discharge oil path 83 b. The oil D can be cooled with the coolant C.

  That is, the oil D whose temperature has been discharged from the hydrostatic bearing 47 is introduced into the introduction pipe portion 84a of the flow path 84 through the discharge oil path 83b. Then, the oil D introduced into the introduction pipe portion 84a flows down to the oil reservoir portion 84b of the flow path 84.

  Here, since the inner peripheral surface 84ba of the oil reservoir 84b is formed in an arc shape along the inner side surface 48d facing the outer peripheral surface 43a of the grinding wheel 43 in the grindstone cover 48, it flows down in the oil reservoir 84b. The oil D is cooled by the coolant C applied to the inner surface 48d of the grindstone cover 48. At this time, the air B around the grinding wheel 43 is also rotated around the outer peripheral surface 43 a of the grinding wheel 43 and is applied to the inner side surface 48 d of the grinding wheel cover 48 to cool the oil D. Since the oil D in the oil reservoir 84b is temporarily retained in the oil reservoir 84b, the oil D is further cooled.

  The oil D in the oil reservoir 84b is led out from the outlet pipe portion 84c of the flow path 84 to the drain pipe 85a of the path 85, and is further returned from the toy 85b to the tank 81 through a hose not shown. Since the air A of the air seal part 46 is supplied from the air introduction pipe part 46a to the discharge oil path 83b, the flow path 84, and the path 85 from the hydrostatic bearing 47 to the tank 81, the discharge oil path 83b, the flow path A force in the discharge direction is applied to the oil flowing through the inside of the passage 84 and the passage 85. Thereby, the oil can be smoothly returned to the tank 81, and the backflow of the oil D inside the discharged oil path 83b, the flow path 84, and the path 85 can be prevented.

  As described above, the oil D in the oil reservoir 84b is cooled by the coolant C and the air B that travels around the outer peripheral surface 43a of the grinding wheel 43 and is applied to the inner surface 48d of the grinding wheel cover 48. By providing the oil reservoir 84b in the grindstone cover 48 below the central axis of the grinding wheel 43 in which a large amount of oil is applied, the oil cooling effect in the oil reservoir 84b can be further enhanced.

  Further, the thickness t between the inner peripheral surface 84ba of the oil reservoir 84b and the inner side surface 48d of the grindstone cover 48 is reduced, and the distance d between the inner side surface 48d of the grindstone cover 48 and the outer peripheral surface 43a of the grinding wheel 43 is the same. By setting the distance, the cooling effect of the oil D in the oil reservoir 84b can be further enhanced.

  As described above, since the oil in the oil reservoir 84b can be cooled, thermal displacement due to heat transfer of oil in a portion related to grinding can be suppressed, and high-precision grinding can be performed. Moreover, since the oil which returned to the tank 81 is cooled, the burden of the apparatus for cooling oil can be reduced, and the energy saving effect can be acquired.

(3. Modified examples)
As shown in FIG. 5, among the inner peripheral surface of the oil reservoir 84b, the inner peripheral surface 84ba on the outer peripheral surface 43a side of the grinding wheel 43 and the inner peripheral surface 84bb facing the inner peripheral surface 84ba in the X-axis direction, Threshold plates 84bc and 84bd extending horizontally in the axial direction are alternately provided. As a result, the oil introduced from the introduction pipe portion 84a flows in a zigzag manner along the threshold plates 84bc and 84bd, so that the oil can be retained in the oil reservoir portion 84b for a long time, and the oil cooling effect is further enhanced. Can do.

  Further, as shown in FIG. 6, a portion of the oil reservoir portion 84be on the introduction tube portion 84a side is formed so as to be a channel 841be having a zigzag side view in the Z-axis direction. Thereby, since the oil introduced from the introduction pipe part 84a flows zigzag along the flow path 841be, it can be retained in the oil sump part 84be for a long time, and the oil cooling effect can be further enhanced. .

  Further, as shown in FIG. 7, a portion of the oil reservoir portion 84bf on the side of the introduction pipe portion 84a is formed to be a flow path 841bf having a substantially V-shaped side view in the Z-axis direction along the inner peripheral surface 84ba. To do. As a result, all the oil introduced from the introduction pipe portion 84a passes near the inner peripheral surface 84ba along the flow path 841bf, so that the cooling effect by the coolant applied to the inner side surface 48d of the grindstone cover 48 is obtained. Can receive enough.

  In the above-described embodiment, the introduction pipe portion 84a is provided at the upper portion of the oil reservoir portion 84b, and the outlet tube portion 84c is provided at the lower portion of the oil reservoir portion 84b. However, the oil reservoir portion 84b is arranged in the X-axis direction. It is good also as a structure which provided the introduction pipe part 84a and the derivation | leading-out pipe part 84c in the front-back part. Further, although the path 85 is provided on the back surface 48a of the grindstone cover 48 (the surface opposite to the workpiece W side in the X-axis direction), the side surface of the grindstone cover 48 (on the bearing housing 49 side in the Z-axis direction). A path 85 may be provided on the opposite surface.

DESCRIPTION OF SYMBOLS 1: Grinding machine, 40: Grinding wheel support device, 42: Grinding wheel base, 43: Grinding wheel, 43a: Outer peripheral surface of grinding wheel, 45: Grinding wheel shaft member, 46: Air seal part, 46a: Air introduction pipe part, 47: Hydrostatic bearing, 48: Grindstone cover, 48d: Inner side surface of grindstone cover, 50: Coolant supply device, 81: Tank, 83a: Supply oil passage, 83b, 83be, 83bf: Discharge oil passage, 84: Flow passage, 84a: Introducing pipe part, 84b, 84be, 84bf: oil reservoir, 84ba: inner peripheral surface of oil reservoir, 84c: outlet pipe part, 85: path, 85a: drain pipe, 85b: toy

Claims (6)

A grinding wheel that grinds the workpiece while rotating,
A liquid bearing for rotatably supporting the grinding wheel;
A tank for storing liquid to be supplied to the liquid bearing;
A grinding fluid supply device that supplies a grinding fluid toward a contact portion with the workpiece in the grinding wheel;
A grinding machine comprising: a grinding wheel cover that covers the grinding wheel and has a flow path for returning the liquid discharged from the liquid bearing to the tank.   2. The grinding machine according to claim 1, wherein the flow path is formed so as to pass through a portion of the inner side surface of the grindstone cover that is sandwiched between a portion facing the outer peripheral surface of the grinding wheel and an outer side surface of the grindstone cover. .   The grinding machine according to claim 2, wherein a liquid reservoir for temporarily retaining the liquid is formed inside the grindstone cover.   4. The grinding machine according to claim 3, wherein an inner peripheral surface of the liquid reservoir is formed in a shape along an inner surface of the grindstone cover that faces the outer peripheral surface of the grinding wheel.   The grinding machine according to any one of claims 1 to 4, wherein air from an air seal that seals a grinding wheel shaft member of the grinding wheel with air is supplied to the flow path.   The grinding machine according to any one of claims 1 to 5, wherein a path leading from the flow path to the tank is provided in a grinding wheel platform on which the grinding wheel is disposed.

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