JP3069264B2 - Thread groove processing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thread groove machining device for grinding a female thread groove engraved on an inner peripheral surface.

[0002]

2. Description of the Related Art For example, a so-called ball screw is known as a work positioning means in a machine tool. The ball screw includes a ball screw shaft provided with a male screw groove, a bearing member provided with a female screw groove on an inner wall surface surrounding an outer peripheral portion of the ball screw shaft, and male and female screw grooves opposed to each other. And a plurality of ball bearings that are interposed between the ball screw shafts and roll. The bearing member is displaced linearly along the axial direction of the ball screw shaft under the rotation of the ball screw shaft.

[0003] In the prior art in which a grinding process is performed on a helical female thread groove formed in a hole of the bearing member, a grinding fluid is ejected from a nozzle communicating with a grinding fluid supply source, and the bearing member is subjected to grinding. The grinding fluid is supplied to the grinding surface of the female screw groove from the outside of the hole, and the finishing of the female screw groove is performed by a grinding tool (grinding stone) rotatably supported by a tool head.

[0004]

However, in the grinding method according to the prior art, at the time of grinding, the ejection port of the nozzle is separated from the hole by a predetermined distance while facing the hole of the bearing member, and the grinding is performed from outside the hole. Since the grinding fluid is supplied to the machined surface, the grinding fluid cannot be sufficiently supplied to the machined surface on which the female screw groove is formed, and the burned surface generates heat and grinding burns occur. There is a disadvantage that it occurs.

Further, in the grinding method according to the prior art, the grinding tool moves forward and backward along the female screw groove defined in the hole of the bearing member, but the grinding fluid is supplied only from one direction of the moving grinding tool. Grinding work is performed in the supplied state.
As a result, since the direction in which the grinding chips are discharged does not match the direction in which the grinding fluid is supplied, the grinding chips ground by the grinding tool remain in the female thread groove without being discharged to the outside by the supplied grinding fluid. As a result, since the grinding operation is performed in a state in which the grinding chips adhere to the grinding tool, there is an inconvenience that the grinding surface is damaged and the processing accuracy is deteriorated.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above-mentioned various inconveniences, and provides a sufficient amount of a grinding fluid to a female screw groove of a bearing member which supports a ball screw shaft, and performs a grinding process. An object of the present invention is to provide a thread groove processing device capable of improving the surface grinding accuracy.

[0007]

In order to achieve the above object, the present invention is directed to a first and second hole portions communicating with a female screw groove formed on an inner peripheral surface of the first hole portion and the second hole portion being separated by a predetermined distance. An apparatus for processing the female screw groove of a defined hollow work, wherein a grinding tool that moves relatively to and retracts from the work under a rotating action by a rotary drive source, and the work is moved to a predetermined position. A holding means for positioning and holding, and a first hole and / or a second hole communicating with a grinding fluid supply source and separated by a predetermined distance from an internal thread groove of the work held by the holding means;
Grinding fluid supply means for supplying the grinding fluid through the hole.

[0008]

In the above-mentioned thread groove machining apparatus according to the present invention, when the female thread groove engraved on the inner peripheral surface of the workpiece is ground by the grinding tool, the grinding fluid supply means communicating with the grinding fluid supply source is used to perform the grinding. The grinding fluid is supplied through the first hole and / or the second hole communicating with the female screw groove.

Accordingly, a sufficient amount of the grinding fluid is supplied to the female thread groove as the grinding surface, and the grinding fluid can be supplied to every corner of the female thread groove. Can be prevented.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a preferred embodiment of a thread groove machining apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram of a thread groove machining apparatus according to an embodiment of the present invention.

The thread groove machining apparatus 10 basically has
Grinding unit 1 in which a grinding wheel (grinding tool) 12 is rotatably held
4, a holding part (holding means) 18 in which the work 16 is rotatably held by a holding mechanism, and a grinding liquid supply part (grinding liquid supply) for supplying a grinding liquid to the work 16 held in the holding part 18. 20).

A work 16 consisting of a bearing member that slides and displaces along a ball screw shaft (not shown) is shown in FIGS.
As shown in FIG. 2C, a hole 22 penetrating along the axial direction is defined, and the inner wall surface of the hole 22 has a helical shape that functions as a rolling groove of a ball bearing (not shown). The internal thread groove 24 is defined in advance by pre-machining.
A pair of return holes (return holes for ball bearings) 26a and 26b are formed in the bottom surface of the work 16 and are separated from each other by a predetermined distance and communicate with the female screw groove 24. The return holes 26a and 26b are described later. Projecting tube 28a,
The work 16 is positioned by inserting the work 28b. A return piece (not shown) is connected to the bottom surface of the work 16, and a passage connecting the pair of return holes 26a and 26b is defined in the return piece. The plurality of ball bearings are drawn out from one return hole 26a (26b) while rolling along the female screw groove 24, and are returned to the other return hole 2 through a return piece passage.
6b (26a), and by rolling along the female screw groove 24 again, the ball bearing can be circulated indefinitely.

The grinding unit 14 includes a motor 32 supported by a support mechanism 30 so as to be swingable in the direction of an arrow, a tool head 34 connected to a motor shaft, and rotating in a predetermined direction under the driving action of the motor 32. The hole 2 is rotatably held at the center of the tool head 34 and defined in the workpiece 16.
2 along the direction of arrow X or Y. By rotating the motor 32, the grindstone 12 integrally connected to the motor shaft via the tool head 34 is rotated, and the female screw groove 24 in the hole 22 defined in the work 16 by the grindstone 12 is formed. It is possible to grind along.

The support mechanism 30 is provided so as to be displaceable in the direction of the arrow X or Y via a displacement means (not shown), and a contact piece 38 is provided on one side surface of the support mechanism 30. When the contact piece 38 abuts on a first sensor 36a or a second sensor 36b described later,
The forward end position or the backward end position of the support mechanism 30 can be detected. The grindstone 12 has a tapered portion 40 whose diameter gradually decreases toward the tip, and a tapered portion 40.
And a grinding portion 42 that abuts against the female thread groove 24 defined in the hole portion 22 of the work 16 and performs a grinding process.

The holding portion 18 is fixed to a base (not shown), and is rotatably fitted in a rotary joint 44 having a substantially cylindrical shape and a through hole defined along the axial direction of the rotary joint 44. Rotating member 50, a protruding portion 46 integrally connected to the rotating member 50 and protruding in a substantially horizontal direction toward the support mechanism 30 side, and a pressing member for holding the work 16 on a flat portion of the protruding portion 46. 48
And a motor 5 for rotating the rotating member 50 in a predetermined direction.
2 (see FIG. 3). Projection 4 of the rotating member 50
6 is provided with a pair of projection tubes 28a, 28b which are disposed corresponding to the pair of return holes 26a, 26b so as to protrude upward, and the pair of projection tubes 28a, 28b are provided.
Is inserted into the corresponding return holes 26a and 26b, whereby the work 16 is positioned on the rotating member 50.

On the sliding surface of the rotary member 50 and the rotary joint 44, first to third annular passages 54a to 54c (see FIG. 3) defined by opposed annular grooves are defined. First to third annular passages 54a to 54
The predetermined portion of c is formed so as to communicate with the first to third switching valves 58a to 58c via passages 56a to 56c, respectively. The first and third annular passages 54a, 54c
Is a passage 56 extending along the axial direction of the rotating member 50.
a, 56c, respectively, through the pair of projection tubes 28a,
28b. Note that the second annular passage 54b is
It is formed so as to communicate with nozzle holes 60a and 60b provided to face the hole 22 of the work 16 via a passage 56b extending along the axial direction of the rotating member 50.

The plurality of nozzle holes 60a and 60b may be arranged circumferentially along the hole 22 of the work 16. It is preferable that the supply amount of the grinding liquid derived from the nozzle holes 60a and 60b is set to be smaller than the supply amount derived from the pair of projection tubes 28a and 28b. Further, the first to third switching valves 58a to 58a-5
8c is always in an off state under the pressing action of the spring member, and receives a control signal derived from the controller 61 to input the first to third switching valves 58a to 58c.
The valve state of c is switched from the off state to the on state.

On the side surface of the support mechanism 30, a first end for detecting the backward end position of the support mechanism 30 displaced in the direction of arrow Y is provided.
A sensor 36a and the support mechanism 3 displaced in the arrow X direction
A second sensor 36b for detecting a forward end position of 0 is disposed at a predetermined distance from the second sensor 36b. The first and second sensors 36
a and 36b are configured by, for example, a limit switch, and the roller 66 protruding from the sensor main body 64 via the arm 62 abuts on the abutting piece, and the arm 62 swings in the direction of the arrow to be displaced. The first or second sensor 36a, 36b is switched from the on state to the off state, or from the off state to the on state. The detection signals output from the first and second sensors 36a and 36b are respectively introduced to a controller 61, and the controller 61 transmits the detection signals to the first and second sensors 36a and 36b.
6b based on the detection signal of the first to third switching valves 58a to 58a
8b, control signals are derived to control the open / close state of the valve.

Below the work 16 held by the holding portion 18, there is provided a receiving tray 68 for storing the grinding fluid discharged from the workpiece 16, and the grinding fluid stored in the receiving tray 68 passes through a passage 70. And is stored in the tank 72. Further, the grinding fluid stored in the tank 72 is sucked by a hydraulic pump 76 to which a filter 74 is connected,
The grinding fluid filtered by the filter 74 is passed through a passage 78.
To the first to third switching valves 58a to 58c, respectively. The passage 78 is provided with a check valve 80 for preventing backflow.

[0021] A thread groove machining apparatus 10 according to an embodiment of the present invention.
Is basically configured as described above. Next, its operation and effect will be described.

First, the protrusion 4 connected to the rotating member 50
The case where the work 16 is positioned and held with respect to No. 6 will be described. A pair of protruding tubes 28 protruding upward from the protruding portion 46 of the rotating member 50 extending in a substantially horizontal direction.
a, 28b, a pair of return holes 26a, 26b defined in the bottom of the work 16 are inserted into the work 16
After the workpiece 1 is positioned, the work 1 is
Hold 6.

Next, the motor 3 held by the support mechanism 30
Under the driving action of 2, the displacement means (not shown) is urged to displace the grinding unit 14 to the backward end position in advance. In this case, it is determined whether or not the grinding unit 14 has reached the reverse end position.
It is detected by the first sensor 36a. That is, when the contact piece 38 provided on the support mechanism 30 contacts the roller 66 of the first sensor 36a and swings the arm 62, the first sensor 36a detects the ON state with respect to the controller 61. A signal is derived. Note that an off-state detection signal is derived from the second sensor 36b to the controller 61.

The controller 61 controls the second switching valve 5 based on the detection signals of the first and second sensors 36a and 36b.
A control signal is derived to the second switching valve 58b and the third switching valve 58c to switch the second switching valve 58b and the third switching valve 58c from the off state to the on state. Therefore, under the urging action of the hydraulic pump 76, the second switching valve 58b and the third switching valve 58
c is opened and the passage 5 communicating with the third switching valve 58c is opened.
6c, one return hole 26b through the annular passage 54c
The grinding fluid is supplied to the hole portion 22 in the work 16 from the projection tube 28b inserted into the second switching valve 58b.
The grinding fluid is supplied from the nozzle holes 60a and 60b facing the hole portion 22 of the work 16 via the passage 56b communicating with the workpiece and the annular passage 54b.

Since the grinding fluid supplied from the projection tube 28b flows in the direction of arrow X along the female screw groove 24 defined on the inner wall surface of the hole 22, it spreads to every corner of the female screw groove 24. The grinding chips generated during the grinding process move along with the grinding fluid along the flow direction. Further, the nozzle hole 60 is formed with respect to the female screw groove 24.
The grinding fluid is supplied by a, 60b and the projection tube 28b, and a sufficient amount of the grinding fluid is supplied to the grinding surface.

As described above, in a state in which the grinding fluid is supplied into the hole portion 22 of the work 16, the motor 52 is rotationally driven to rotate the rotating member 50 held by the rotary joint 44 in a predetermined direction. The work 16 is rotated integrally with the member 50 in the direction of the arrow. On the other hand, the motor 3
2 to rotate the grindstone 12 in a predetermined direction, and urge a displacement means (not shown) so that the support mechanism 30 is moved in the arrow X direction (forward path) so that the grindstone 12 is inserted into the hole 22 of the work 16. The female thread groove 24 defined on the work 16 by the grinding portion 42 of the grindstone 12 is displaced.

In this case, the grinding fluid supplied from the projection tube 28b inserted into the one return hole 26b is
4 and the discharge direction (arrow X direction) of the grinding chips generated by grinding by the grinding portion 42 coincide with each other. Is discharged to the outside together with the grinding fluid without remaining. Further, since a sufficient amount of the grinding fluid is supplied to the female thread groove 24 as the grinding surface by the nozzle holes 60a and 60b and the projection tube 28b, it is possible to prevent grinding burn caused by insufficient supply of the grinding fluid. it can. In addition,
The grinding fluid discharged to the outside of the work 16 is stored in a receiving tray 68 provided below the work 16, stored in a tank 72 via a passage 70 connected to the receiving tray 68, and reused.

The second sensor 36b detects that the support mechanism 30 supporting the grinding wheel 12 has been displaced in the direction of the arrow X under the rotating action of the work 16 and the grinding wheel 12, and has reached the forward end position. Is turned on,
The second sensor 36 b derives an ON-state detection signal to the controller 61. At this time, the first sensor 36a
Is off from the contact piece 38, and an off-state detection signal is output to the controller 61.

The controller 61 includes the first and second
Based on the detection signals from the sensors 36a and 36b, a control signal for switching from the off state to the on state is transmitted to the first switching valve 58.
a, and a control signal for switching the third switching valve 58c, which has been held in the on state, to the off state. Therefore, when the first switching valve 58a is opened, the grinding fluid supplied from the hydraulic pump 76 can be supplied to the female thread groove 24 through the other projection tube 28a inserted into the return hole 26a. The grinding fluid supplied from the projection tube 28a flows along the female screw groove 24 in the arrow Y direction. Also, the second switching valve 58b
Is kept on while the grinding process continues,
The supply of the grinding fluid from the nozzle holes 60a and 60b is continued.

Subsequently, the grindstone 12 is moved in the direction indicated by the arrow Y in the opposite direction (return path) under the switching action of a displacement means (not shown).
Then, the female thread groove 24 defined on the inner wall surface of the work 16 by the grinding section 42 is ground. In this case, the grinding chips generated when the grinding surface is ground in the forward direction (the direction of the arrow X) are discharged outside by the grinding fluid and do not remain, so that the grinding direction is not damaged and the returning direction ( Grinding in the direction of arrow Y) can be performed.
Also, sufficient grinding fluid is supplied in the backward direction as in the forward direction, so that the occurrence of grinding burn can be prevented.

As described above, in the thread groove machining apparatus 10 according to this embodiment, the work 16 supporting the ball screw shaft is supported.
When grinding the internal thread groove 24, since a sufficient amount of grinding fluid can be supplied to the internal thread groove 24,
The occurrence of grinding burn due to frictional heat can be prevented.
In addition, since the flow direction of the grinding fluid supplied to the female thread groove 24 can be switched in accordance with the advance / retreat operation of the grindstone 12, the grinding debris ground by the grindstone 12 is discharged to the outside without remaining in the female thread groove. can do. As a result, the grinding accuracy can be improved without damaging the ground surface.

[0032]

According to the thread groove machining apparatus of the present invention,
The following effects can be obtained.

That is, since the grinding fluid is supplied through the first hole and / or the second hole communicating with the female thread groove defined in the work, a sufficient amount of the grinding fluid is supplied to every corner of the female thread groove. It is possible to prevent grinding burn due to frictional heat.

Further, by switching the supply direction of the grinding fluid to the first hole portion or the second hole portion corresponding to the grinding tool that moves forward and backward, the grinding fluid is supplied along the grinding direction of the grinding tool that moves forward and backward. Can be distributed. As a result, the grinding waste generated by the grinding process is not discharged to the outside together with the grinding fluid and remains on the grinding surface, so that the grinding accuracy can be improved without damaging the grinding surface.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a thread groove processing device according to an embodiment of the present invention.

2A and 2B are cross-sectional views of a work to be ground by the thread groove processing apparatus shown in FIG. 1, FIG. 2A is a front view of the work, and FIG. 2B is a longitudinal section taken along line BB shown in FIG. 2A; FIG. 2C is a vertical cross-sectional view along the line CC shown in FIG. 2A.

FIG. 3 is a sectional view of a main part of the thread groove processing device shown in FIG. 1;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... thread groove processing apparatus 12 ... grinding stone 14 ... grinding part 16 ... work 18 ... holding part 20 ... grinding fluid supply part 22 ... hole part 24 ... female screw groove 26a, 26b ... return hole 28a, 28b ...
Projection tube 30 Support mechanism 32, 52 Motor 36a, 36b Sensor 50 Rotating member 54a-54c Annular passage 56a-56c,
70, 78 ... passages 58a-58c ... switching valves 60a, 60b ...
Nozzle hole 61 Controller

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Tatsuya Takeuchi 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (56) References JP-A-7-24693 (JP, A) JP-A Sho 54 -100598 (JP, A) JP-A-6-39638 (JP, A) JP-A-1-222817 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23G 1/36 B24B 5/06 B24B 55/02

Claims (3)

(57) [Claims] An apparatus for processing said female thread groove of a hollow workpiece in which a first hole and a second hole communicating with a female thread groove engraved on an inner peripheral surface are separated by a predetermined distance. Under the action of rotation by a rotary drive source, a grinding tool that moves forward and backward relative to the work, holding means for positioning and holding the work at a predetermined position, and a grinding fluid supply source, Grinding fluid supply means for supplying grinding fluid through a first hole and / or a second hole which is separated by a predetermined distance from a female thread groove of the work held by the holding means. Processing equipment. 2. The apparatus according to claim 1, wherein the grinding fluid supply means has a switching means for switching the supply of the grinding fluid to the first hole or the second hole in accordance with the reciprocating operation of the grinding tool. A thread groove processing device characterized by the above-mentioned. 3. The apparatus according to claim 1, wherein the workpiece includes a bearing member that supports a ball screw shaft via a plurality of rolling ball bearings, and the first member is defined by the bearing member. And the second hole is a return hole for rolling and circulating the ball bearing along the female screw groove.