US2978844A - Vibrating internal grinding machine - Google Patents

Description

April 11, 1961 MlSAO UMEDA 2,978,844

VIBRATING INTERNAL GRINDING MACHINE Filed May 1, 1958 2 Sheets-Sheet 1 M I '1 of INVENTOR. M ISAO U M E D A ATTOI? NEY April 11, 1961 M|5AO UMEDA 2,978,844

VIBRATING INTERNAL GRINDING MACHINE Filed May l, 1958 2 Sheets-Sheet 2 BY I ATTORNEY United States Patent VIBRATING INTERNAL GRINDING MACHINE Misao Umeda, Funakoshi-cho, Aki-gun, Hiroshima-ken, Japan, assgnor to Toyo Kogyo Company Limited, Aki-gun, Hiroshima-ken, Japan Filed May 1, 1958, Ser. No. 732,404

3 Claims. (Cl. 51-34) The object of this invention lies in raising the efficiency and accuracy of work, as Well as, broadening the range of grindstone selection and meeting economical requirements by furnishing the grinding stone of the internal grinding machine with rotation and, simultaneously, minute axial movements.

Another object of this invention is to constantly attain a uniform and superior cutting quality of the grindstone and work accuracy by suspending, if necessary, the minute axial movements of the grindstone and dressing it.

Another object of this invention is to support the grindstone so as to enable it to rotate freely and, also, to reciprocate accurately towards the axial direction by remodeling the ball bearing, supporting it, and to facilitate the manufacturing of a vibrating internal grinding machine suited to effect the foregoing purposes.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification considered in conjunction with the accompanying drawings illustrative of one embodiment thereof, but it will be understood that any modifications may be made in the specific structural details within the scope of the appended claims without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate like or similar parts:

Fig. 1 is a side view of the machine partially in section.

Fig. 2 is a front view of the same partially in section.

Fig. 3 is a cross sectional view.

Fig. 4V is a view, partly in section, illustrating the operating parts of the machine.

As indicated in Fig. 4,'the oil under pressure delivered from the oil pressure pump 1 is guided to the three-way valve 4 and the magnetic valve 5 by the pipe 3 while being regulated to a constant pressure by means of the pressure regulating valve 2 and, then passing through the pipe 7 lfrom the port 6 of the three-way valve 4, the oil under pressure is guided into one end of the dressing cylinder 8 and the admission port 12, which opens in the valve chest 11 established in the valve housing 10 through the throttle valve 9. The slide valve 14 is tted tightly inside the three-way valve 4 so as to slide freely and allow communication through lthe pipe 3 and the port 6 when the slide valve 14 is shoved at one end by the spring 13. ln case `this slide valve 14 slides in a different direction compressing the spring.13, the slide valve 14 will cut orf the communication through the pipe 3 and the port 6 and allow the port 6 to communicate with the oil tank l16 by means of the drain pipe 15. Also, the slide valve 19, which slides axially effected by the electromagnet '17 and the spring 18, is inserted into the magnetic valve and communication through the pipe 3 or ythe drain pipe 15 with the valve port 20 is alternately effected by sliding movement of the slide valve 19. In other words, its structure is so arranged, when the electric circuit of the electromagnet 17 is closed, it will allow .the communication of the pipe 3 to the valve port 20 and, also, when the electric circuit of the electromagnet ice 17 is opened, the slide valve 19 as illustrated slides by means of the spring 18 and permits communication through the drain pipe and the valve port 20. The valve port 20 is connected to one end of the three-way valve 4 by the pipe 21 which also is connected with the oilfeed port 23 inside the safety valve housing 22 tted with the safety valve 27 depressed during grinding operation by the cam 26 fixed on the head housing 25 which slides on the table 24, and, during the duration of time that said safety valve 27 is being depressed by the cam 26, the communication of the oil-feed pipe 28 connected to the other end of the said dressing cylinder 8 and the pipe 21 is effected by the port 30 and check valve 29 established on one side of the safety valve housing 22. Also when safety valve 27 is relieved of depression from the cam 26, the safety valve 27 is moved by the oil under pressure fed from pipe 21 to oil-feed port 23, then, the oil under pressure is fed from oil-feed port 23 to oil-feed pipe 28 through the branch port 31 and the port 30, then, the dressing piston 32 inside the dressing cylinder 8 is energized, and then the arm 34 which engages with the rack 33 joined to this dressing piston 32 is rotated and the diamond 35 iixed on the tip of this arm faces the locusV Aof the rotation of the grindstone 36 surface.

The said admission port 12 communicates alternately to the openings 38 and 39 through the valve chest 11 by means of the control valve 37 inserted tightly inside the valve chest 11 in a manner to allow it to slide freely,`

and, when the openings 38 or 39 do not communicate to the admission port 12, they communicate with the drain port 41 or 42 respectively connected to the oil tank 16 by means of the pipe through the valve chest 11. The control valve 37 is always depressed and slides to one side by means of the spring 43 and allows the communications between the admission port 12 and the opening 38 and between the opening 39 and the drain port 42, the adjustment of which is effected by adequately rotating the adjusting screw 45 screwed to one end of the valve chest 11 against the spring 44. Inside the valve housing 10, on one side of and parallel to the valve chest 11 is established the valve chest 46 wherein the piston valve 47 anked on both ends by the springs 48 and 49 is tted on so as to provide it free sliding movements, the displacement length of the springs 48 and 49, namely, the slide length of the piston valve 47 is adjusted by rotating the adjusting screw 50 screwed on one end of the valve chest 46. Communications from :left and right end chembers 51 and 52 of the valve chest 46 to aforementioned openings 38 and 39 are respectively provided for by the passages 53 and 54 and the left-end chamber 51 and right end chamber 52 are constructed so that the former and the latter by sliding movements of piston valve 47 will respectively communicate alternatively with the right end chamber 55 of the valve chest 11 by means of the passage 56 and with the left end chamber 57 of the valve chest 11 by means of the passage 58. The valve chest 46 is connected with the pipe 40 by means of the passage 59 which also alternatively is connected with the passages 56 or 58 through the openings 60 or 61 respectively by means of sliding movementsof the piston valve 47.

The said valve housing 10 is fixed on top of the head housing 25 which slides on the table 24 and the wheelhead proper 63 is fitted to center hole 62 of this head housing 25, a swinging lever 64 attached lto valve housing 1l), and both ends of the lever 64 join the wheelhead proper 63 and the'said piston valve 47 respectively, therefore, axial reciprocations of the wheelhead proper 63 are elfeeted by reciprocations of the piston valve 47 and, in this case, the guide piece 66 is attached to the head housing 25 by means of an adjustable bolt 65 and the guide piece 66 is fitted into the guide groove 67 formed on the wheelhead proper 63 to provide the wheelhead proper 6 3 Patented Apr. 11, 196.1

an accurate axial reciprocating movement without rotation as shown in Figs. 1 and 2. The grindstone spindle 69 which is rotated by means of the pulley 68 as is with conventional internal grinding machines is supported by the'wheelhead proper 63 so to give the ygrindstone spindle69 a free rotating movement and the grindstone 36 is iixed on one end of the said grindstone spindle 69. An oblique part 70 is provided at each end of the wheel head proper 63 with an inner race 72 having a slit 71 fitted therein. The balls 76 are tted intoV the holes 75 of the holding race 74 which is between the inner race 72 and outer race 73 which is attached at each end of the center hole 62 of the head housing 25. The pin 77 Vprojecting from the holding race 74 is fitted into the slit 71 to prevent the circumferential movement of the balls 76 in relation tothe inner race 72. The inner side of the inner race 72 is always depressed towards release direction by means of the spring 78 insertedinside of the Wheelhead proper 63 and outer side of the inner race 72 is depressed by the adjusting nut 86 screwed onto the thread 79 of the Wheelhead proper 63 and the adjusting nut Stlis fastened to the wheelhead proper 63 by the lock nut 81 which is screwed on the outer side of the adjusting nut 80.

The fitting of the inner race 72 deep into the oblique part 70 or else extracting this towards release direction is accomplished by adequately rotating the adjusting nut 80. The axial displacement of this inner race 72 will minutely alter its'outer diameter and adjust the clearance between the inner race and the balls 76 inserted between the inner and outer races, so it is constructed that the wheelhead proper 63 is reciprocated axially constantly with a swift and smooth slide on the same center line with lchel grindstone spindle 69.

According to this invention, the oil under pressure, when led tothe pipe 3 by actuating the oil pressure pump 1v as illustrated in Fig. 4, enters one end of the dressing cylinder 8 by way of the pipe 7 from the port 6 of the three-way valve 4, depresses the dressing piston 32 and simultaneously diamond 35 on arm 34 is positioned outside of rotating locusl of the grindstone 36 surface and, by means of the throttle valve 9., it is led into the valve chest 11 from the admission port 12, enters the left-end chamber 51 of the piston valve 47 through the passage 53 from the ropening, 38 and a'ctuates the movement of the piston valve 47 to the right, whereby as the oil, which iills up inside the right-end chamber v52, is drained into the oil tank 16 from the pipe 40 by Way of the passage S4, opening 39, valve chest 11 and drain port 42, no resistance is inflicted on the right movement of the piston valve 47. When the piston valve 47 moves right in this manner, the Vopening 60 and the passage 53 is intercepted and communications of the opening 61 and the passage 59 and also the left-end chamber 51 and the passage 56 are respectively opened, the oil under pressure inside the left-end chamber 51 enters the right-end chamber 5 of the control valve 37 by way of passage 56, actuating the left movement of control valve 37 whereby the oil filled in the left-end chamber 57 is drained into the oil tank 16 from the pipe 40 by way of the passage 58, opening 61, valve chest 46, passage 59 and drain port 42, and therefore, left movement of the control valve is effected without any resistance encountered. When the control valve 37 moves left, the communications of the admission port 12 and the opening 38 and also the opening 39 and the drain port 42 are both intercepted and as the communications of the admission port 12 and the opening 39 and also the opening 38 and thedrain ports 41 are respectively opened by means of the valve chest 11, the oil under pressure enters the right-end chamber 52 of the piston Valve 47 from the passage 54, actuating the left movement of the piston valve-47, lwhereby the oil inside the left-end chamber 51 is drained into the drain port 41 by way of the passage 53, opening 38 and valve chest 11. Thus, when the-piston valve 47 moves to the left, the passage 56 and the opening 61 are intercepted and, also, the communications of the opening 60 and the passage 59 and also the right end chamber 52 and the passage 58 being respectively opened, the oil under pressure inside the right end chamber 52 enters the left end chamber 57 of the control valve 37 by way of passage 58, whereas the communication of the right end chamber 55 of the control valve 37 is opened to the drain port 42 by way of the passage 56, opening 60, Valve chest 46 Vand passage 59, so that the control valve 37 moves right, and, the control valve 37 is restored to the condition as illustrated in Fig. 4, and, with a repetition of the foregoing operation, the piston valve 47 being provided with minute and accurate reciprocal movements, the speed and length of which may be freely controlled by -adjusting the throttle valve 9 and the springs 48 and 49.

Consequently, when the piston valve 47 repeats the minute and accurate reciprocal movements axially in the manner as explained above, the wheelhead proper 63 is provided withl axial reciprocal movements by means of lever 64, and both ends of the vsaid Wheelhead proper 63 are provided with an oblique part 70 to which the inner race 72 with a slit 71 is tted so as to slide freely, balls 76 are fitted in between the said inner race 72 and the outer race 73vtitted on both ends of the head housing 25 and by means of the adjusting nut 86, said inner race 72 is moved axially on the oblique part 70 with the outer diameter Vof the inner race 72 being minutely changed and adjusting the clearance between the said inner race 72 and the said balls 76 inserted between the inner race 72 and outer race 73, the wheelhead proper 63 is always made to smoothly reciprocate axially on the same center line with that of the head housing 25. Therefore the grindstone spindle 69 supported by the wheelhead proper 63 minutely reciprocates axially on the same center line While rotating, and the grindstone 36 grinds the surface of the work, and the accuracy of the work can be always maintained Vby rotating the adjusting nut 80 and making the inner race 72 to slide on the oblique part 70 the wheelhead proper 63, in case clearance between the inner race 72 and the balls 76 inserted between the inner race 72 and the outer race 73 change may occur owing to wear of the balls 76 or inner race 72 or outer race 73.

Then, during the aforementioned operation, the head housing 25 which supports the wheelhead proper 63 advances forward on table 24 to the position of the opera tion and the cam 26 located on the top of the safety valve 27 depresses it, the communication of pipe 21 and the oil feed pipe 28 is intercepted. However, when the head housing 25 is made to retreat along the table 24 when dressing the grindstone 36 with a diamond 35 after the grinding operation is finished, the cam 26 parts from the safety valve 27 which then is freed. and thereupon when closing the electric circuit of the electromagnet 17, the slide valve 19 is drawn by the electromagnet 17 and slides while compressing the spring 18 and intercepting the communication of the drain pipe 15 and the valve port 2t), simultaneously opens the communication of the pipe 3 and the valve port l20, the oil under pressure entering at one end of the three-way valve 4 from pipe 21 slides the slide valve 14 to the other end while compressing the spring 13 and intercepting the communication of the pipe 3 and the port 6, the communication of the port 6 and the drain pipe 15 is opened, whereby the reciprocal movements of the pistonvalve 47 stops and no pressure exists inside the dressing cylinder 8. At the same time, the slide of the' safety valve 27 is actuatedby the oil under pressure fed to the oil-feed port 23 of the safety valve housing 22 from Ythe pipe 21, the communication of the said oil-feed port 23 and the oil-feed pipe 23 is opened by means of the branch port 31 and theA passage 30, whereby the oil under pressure is fed to the other-lend rofy the dressingcylinder '8 and` sliding -the dressing piston 32, the arm 34 is rotated by the rack 33 jointed to the said dressing piston 32, the diamond 35 is made to face the rotation locus of grindstone 36 surface to which the essential dressing is administered.

Thus, when the circuit `of the electromagnet is closed during grinding operation, the reciprocal movements of the piston valve is stopped, so that the minute axial movements of the grindstone is stopped, but, the diamond will not Iface the rotation locus of the grindstone surface as long as the safety Valve is depressed by the cam. And, also, when the head housing is retreated on the table and the safety valve is unrestrained, the diamond will not face the rotation locus of the grindstone surface as long as the electromagnet circuit is not closed As explained in the doregoing lines, the grindstone rotating with the grindstone spindle and constantly re- `peating a minute and accurate axial reciprocating movement grinds the surface of the work, so that this invention produces an extremely superior cutting quality of the `grindstone and simultaneously an exceedingly fine accuracy of the work. Further, this grindstone may be dressed with the diamond by stopping the grinding operation and the minute axial movement of the grindstone at any optional time, and then the grinding operation is resumed, so that this invention produces a uniform cutting quality of the grindstone and accuracy of work. Consequently, according to this invention, a high precision and elliciency grindstone is not absolutely required of as was essential with the high precision and efficiency internal grinding machines hitherto, the grindstone selection is made optional with high economical effects also attainable. And, also, another `big feature of this invention produces a vibrating internal grinding machine having such said superior precision and eticiency with a very simple mechanism and low cost.

What I claim is:

1. In a vibrating internal grinding machine having a table, =a head housing having a center hole slidable on 'said table, a valve housing xed to the top of the head housing, a swinging lever attached to said valve housing, `a wheel head proper litted to the center hole of the head housing, a piston valve in said valve housing, both ends of said swinging lever joining the wheel head proper and said piston valve whereby axial reciprocations of the wheel head proper are eiected by reciprocations of said piston valve, an adjustable bolt, a guide piece attached to the head housing by means of said adjustable bolt, a guide groove formed on the Wheel head proper to provide the wheel head proper an accurate axial reciprocating movement without rotation.

2. In a vibrating internal grinding machine, a grinding spindle, a pulley for rotating the same, -a threaded wheel head proper supporting said grinding spindle, a grindstone fixed to the end of said grinding spindle, an oblique part provided at Aboth ends of the wheel head proper, an inner race, an outer race and a holding race provided with holes on said wheel head proper, said inner race possessing a slit, balls fitted into the holes of the holding race and inserted between the inner race and the outer race, said holding race being fitted into said slit to prevent the circumferential movement of said balls in relation to the inner race, an adjusting nut `and a lock nut, said adjusting nut being secured onto the thread of the wheelhead proper and lfastened by the lock nut `which is screwed on the outer side of the adjusting nut.

3. In a vibrating internal grinding machine, a grinding spindle, a pulley .for rotating the same, a wheel head proper supporting said grinding spindle, a grindstone xed to the end of said grinding spindle, an oil pressure pump, a dressing cylinder, a head housing mounted on a table for supporting the Wheel head proper, a cam mounted on said head housing, a safety valve actuated by said cam, a slide valve, an electromagnet for closing said slide Valve, a three Way valve, another slide valve within the three way valve, a spring for normally closing said slide valve, an oil feed pipe connecting said safety valve housing to said dressing cylinder, a dressing piston inside the dressing cylinder actuated by the oil in said oil feed pipe, an arm and rack joined to said dressing piston and actuated thereby and a diamond on the end of said arm.

References Cited in the tile of this patent UNITED STATES PATENTS 2,175,057V Kearns Oct. 3, 1939 2,395,544 Galloway Feb. 26, 1946 2,409,240 Barker et al. Oct. l5, 1946 2,409,450 Silven Oct. l5, 1946 2,804,751 Schrodeder Sept. 3, 1957

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