JPS6334841Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Field of Industrial Application) The present invention relates to a feed control device for a grinding machine that allows a grinding wheel to approach a workpiece at a rapid feed speed, and then switches to cutting feed to process the workpiece. It is something.

(Prior technology) When installing a workpiece on a grinding machine, if the grindstone is close to the workpiece, it will interfere with the workpiece installation, so the grindstone is placed at a distance from the workpiece, and when processing the workpiece, the grindstone approaches the workpiece. The machining time is shortened by fast forwarding until the grinding point is reached and then switching to cutting feed to reduce idle grinding time. For this reason,
It is desirable to rapidly feed the grinding wheel and the workpiece until they are as close as possible to shorten the machining time, but due to wear of the grinding wheel during machining, variations in workpiece dimensions, etc. There was a problem in that it was not possible to bring it close to the workpiece.

For this reason, in the past, the amount of wear on the grinding wheel was predicted in advance and a wear compensation cam was used to correct the feed speed switching position of the grinding wheel, which was called the correction cam method. A method of detecting changes in rotational driving force and switching the feed rate (for example, see Japanese Patent Application Laid-open No. 72796/1983),
Methods such as detecting the contact sound when the grinding wheel contacts the workpiece and switching the feed speed are used to reduce dry grinding time. However, with the correction cam method, there is a problem that the predicted amount of wear on the grinding wheel does not necessarily match the actual amount of wear, and it is not possible to compensate for variations in the dimensions of the workpiece, so the speed switching position must be set in consideration of this dimensional variation. There is a problem. In the method of detecting changes in the rotational driving force of the grinding wheel, there is a detection delay due to the rotational inertia of the grinding wheel shaft system, and since the cutting feed is switched after contact, there is a risk of impact on the grinding wheel and damage to the grinding wheel at the time of contact. Furthermore, in the method of detecting contact sound, there is a risk of detecting noise other than the contact sound, and as with the rotational driving force detection method, there is also a risk of damage to the grindstone due to the impact at the time of contact.

(Purpose of the invention) In view of the above-mentioned circumstances, the present invention is a feed control device that can always switch the feed speed immediately before the grinding wheel and the workpiece come into contact, regardless of wear of the grinding wheel, variations in the dimensions of the workpiece, etc. The purpose is to provide the following.

(Structure of the invention) The feed control device for a grinding machine of the invention supports a grinding wheel head on a base so that it can move back and forth with respect to the work table, and the grinding wheel head is moved at a rapid speed and speed by a grinding wheel head feeding device. A holding member that can be moved back and forth at the cutting feed rate, is supported by a grinding wheelhead, and can be moved back and forth by a predetermined stroke in the direction of movement of this grinding wheelhead, is always urged forward by an elastic member, and this holding member is A member supports a contact rod whose front end can come in contact with a workpiece so as to be movable back and forth, and a friction lock mechanism brings the holding member and contact rod into frictional engagement with a friction force greater than the biasing force of the elastic member, and the grindstone head is rotated. After being sent to the grindstone feeder and moving forward, and the contact rod comes into contact with the workpiece,
During a predetermined stroke, the contact rod and the holding member are integrally engaged and held by frictional force against the biasing force of the elastic member, and after the predetermined stroke, the contact rod is engaged with the holding member against the frictional force. At the same time, a detection switch detects the movement of the holding member relative to the grinding wheel head, and a speed switching device controls the grinding wheel head feeding device in response to this detection signal to switch from rapid feed to cutting feed. It is characterized by this.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing an example of a grinding machine having a feed control device according to the present invention. A workpiece 2 is supported on a workbench 1 at the front of the grinding machine (the left side in the figure is the front), and a grindstone head 4 is supported on a base 3 that does not move relative to the workbench 1 so as to be movable back and forth. has been done. A grindstone shaft case 16 for rotatably supporting a grindstone shaft 15 and a drive motor 11 for rotationally driving the grindstone shaft 15 are fixedly installed on the grindstone head 4. Rotation is transmitted from the drive pulley 12 via the belt 13 to the driven pulley 14 attached to the rear end of the grindstone shaft 15, thereby rotating the grindstone shaft 15 and rotating the grindstone 17 attached to the front end of the grindstone shaft 15. .

A cylinder case 5f of a hydraulic cylinder 5 is fixed to the rear end of the grindstone head 4, and a piston rod 5c of the hydraulic cylinder 5 is slidably guided back and forth by a guide stand 3a fixed to the base 3. At the same time, a male screw is formed on the rear end portion 5e, and is screwed into a female screw provided on the output shaft 6a of the pulse motor 6 fixed on the base 3. Through this screwing, the piston rod 5c is indirectly screwed into the base 3, and the piston rod 5c is held fixed to the base 3 as long as the pulse motor 6 does not rotate. For this reason, the grindstone head 4
When hydraulic pressure is supplied to the oil supply ports 5a and 5b provided above, since the piston rod 5c is fixed, the cylinder case 5f is moved and at the same time the grinding wheel head 4 is moved.
is also moved. On the other hand, when the pulse motor 6 is rotated, this rotation moves the piston rod 5c back and forth according to the thread pitch of the threaded portion, and the cylinder case 5f of the hydraulic cylinder 5 and the piston rod 5
As long as there is no relative movement c, the grindstone head 4 is also moved back and forth. That is, the grindstone head 4 can be moved back and forth by supplying hydraulic pressure to the oil supply ports 5a and 5b or by operating the pulse motor 6. On the other hand, a rod support case 20 is fixedly installed on the whetstone shaft case 16 fixed to the whetstone head 4, and a storage member 25 is attached to the rod support case 20 so as to be slidable back and forth. 25 is always urged rearward by a storage spring 22 supported by a ring 21 fixed to the rod support case 20. However, since hydraulic pressure is supplied from the port 23 into the storage cylinder chamber 24 formed between the rod support case 20 and the storage member 25 during operation of the grinder, the storage member 25 is not affected by the biasing force of the storage spring 22. I am being pushed forward against it. The forward movement of the storage member 25 is stopped by the storage flange 26 fixed to the rear end of the storage member 25 coming into contact with the rear end surface of the rod support case 20. 20 is integrally held. Note that when the grinder is not operating, the hydraulic pressure is not supplied from the port 23, and the storage member 25 moves rearward by the distance indicated by "G" in the figure due to the biasing force of the storage spring 22.

A holding member 30 is inserted into the storage member 25 so as to be slidable back and forth, and a contact rod 33 is inserted into the inside of this holding member 30 so as to be slidable back and forth. Do 3
3 are frictionally engaged with each other by a friction lock mechanism 32. This friction lock mechanism 32 is provided at the rear end of the holding member 30, and is adapted to press a friction shoe 32b against the contact rod by a lock spring 32a. The holding member 30 is configured to sandwich the storage member 25 with a gap "F" between the front end flange 30a and the rear end flange 30b. A contact spring 31 as an elastic member is disposed between the outer periphery of the holding member 30 and the inner periphery of the storage member 25, with its front end in contact with the holding member 30 and its rear end in contact with the storage member 25. 3
0 is always urged forward with respect to the storage member 25. At this time, the biasing force of the contact spring 31 is set to be smaller than the frictional force of the friction lock mechanism 32. Therefore, when the contact rod 33 is pushed backward, the contact rod 33 is pushed backward during a predetermined stroke determined by the gap F. 33 and holding member 30
The contact spring 31 remains integrally engaged.
After the predetermined stroke, the front end flange 30a of the holding member 30 comes into contact with the front end of the storage member 25, so that it contacts the holding member 30 against the frictional force of the friction lock mechanism 32. Only the rod 33 is designed to move backward.

Further, a support plate 41 is attached to the upper part of the rod support case 20, and the rear end flange 30 of the holding member 30 is attached to the rear end of the support plate 41.
The detection switch 40 is attached opposite to the rod support case 20, and the holding member 30
It is designed to detect movement. When the movement of the holding member 40 is detected by the detection switch 40, a detection signal is sent from the line 41 to the speed switching device 42.
The rotation speed of the pulse motor 6 is controlled via the .

The case where the workpiece 2 is ground using the grinding machine configured as described above will be described with reference to the graph shown in FIG. 2.

First, in order to rapidly bring the grindstone 17, which has been away from the workpiece 2 closer to the workpiece 2 so as not to interfere with the installation of the workpiece 2, oil pressure is supplied to the oil supply port 5a of the hydraulic cylinder 5 to rapidly move the grindstone head 4 forward at a constant pressure. Therefore, the front end of the grindstone 17 rapidly moves from position A to position B. When reaching position B, that is, the stroke end of the hydraulic cylinder 5, the pulse motor 6 begins to be driven to rotate at a relatively high speed (approximately 500 to 1000 pps). For this reason, the piston rod 5c
The grindstone head 4 rapidly moves forward at a constant speed in accordance with the screw pitch of the threaded portion between the rear end portion 5e and the output shaft 6a of the pulse motor 6. For this reason, the front end of the grinding wheel 17 moves further forward relatively quickly from the position B, but the front end 33a of the contact rod 33 is positioned in front of the front end of the grinding wheel 17 by a distance F.
Before the front end of the grindstone 17 comes into contact with the workpiece 2, the front end 33a of the contact rod 33 comes into contact with it, and the contact rod 33 is pushed backward. When the contact rod 33 is pushed rearward, the holding member 30 engaged by the friction lock mechanism 32 is also pushed rearward, and this movement is detected by the detection switch 40. Therefore, the speed switching device 42 switches the rotation of the pulse motor 6 to feed rotation for cutting (1 to 10 pps). Therefore, at the front end of the grindstone 17, at a position C at a distance F (approximately 10 μm) from the workpiece 2, the feed rate is switched from constant rapid forward movement to constant forward cutting speed (cutting feed rate). After this, grindstone 17
The front end contacts the workpiece 17 at position D to start grinding, and the grinding is completed at position E where it is ground to a predetermined size.

On the other hand, after the front end 33a of the contact rod 33 comes into contact with the workpiece, the contact rod 33 retreats by the distance F, reaches the same position as the front end of the grinding wheel 17, moves forward together with the grinding wheel 17, and when the grinding is completed, the grinding wheel 17 is returned. Then, due to the urging force of the contact spring 31, the grinding wheel 17 is again located at a position protruding forward by a distance F from the front end thereof. Now, considering the case where the grinding wheel 17 wears out as the grinding progresses, the front end 33a of the contact rod 33 is pushed back to the same position as the front end of the grinding wheel 17, so when the grinding wheel 17 wears out, the contact rod 33 also becomes larger than the dimension F. being pushed back. When the amount of retraction of the contact rod 33 exceeds the dimension F, the holding member 30 comes into contact with the storage member 25 as described above, and only the contact rod 33 retracts against the frictional force of the friction lock member 32. . However, even after the grinding is completed, the friction force of the friction lock member 32 is greater than the biasing force of the contact spring 31, so the contact rod 33 and the holding member 3
0 is moved back forward by only the dimension F. In other words, even if the grinding wheel 17 wears out, the contact rod 33
The front end 33a of is located a distance F forward from the front end surface when worn.

Therefore, with this grinder, the feed rate can always be switched immediately before the grindstone contacts the workpiece (at a position separated by the dimension F), regardless of variations in the dimensions of the workpiece 17 or wear of the grindstone.

In this embodiment, the contact rod 33 is caused to protrude forward from the grinding wheel 17 as described above while the grinder is in use due to the action of the hydraulic pressure supplied from the storage spring 22 and the port 23 into the storage cylinder chamber 24. When the grinder is not in use, the supply of the hydraulic pressure is cut off and the storage member 25 is closed by the storage spring 23.
The contact rod 33 is moved backward and recessed to the rear of the contact rod 33 from the grindstone 17 to protect the contact rod 33.

(Effects of the invention) As explained above, according to the invention, it is possible to always change the feed speed of the grinding wheel from rapid feed to cutting feed immediately before the grinding wheel contacts the work, regardless of workpiece size variations or grindstone wear. As a result, the dry grinding time can be minimized to shorten the machining time, and the shock when the grinding wheel and workpiece come into contact can be reduced, thereby preventing damage to the grinding wheel and improving machining accuracy.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an example of a grinding machine having a feed control device according to the present invention, and Fig. 2 shows the relationship between the feed amount of the grinding wheel and time when it is fed by the feed control device according to the present invention. It is a graph. 2...Workpiece, 3...Base, 4...Whetstone stand, 5
...Hydraulic cylinder, 6...Pulse motor, 11...
... Drive motor, 17 ... Grindstone, 25 ... Storage member, 30 ... Holding member, 31 ... Contact spring, 32 ... Friction lock mechanism, 33 ... Contact rod, 40 ... Detection switch.

Claims (1)

[Scope of Claim for Utility Model Registration] A work table on which a work is supported; a grind stone table on which a grindstone is mounted and supported on a base so as to be movable back and forth with respect to the work table; a grinding wheel head feeding device capable of moving back and forth at a cutting feed rate, supported by the grinding wheel head, capable of back and forth movement of a predetermined stroke in the moving direction of the grinding wheel head, and constantly biased forward by an elastic member. a holding member; a contact rod that is supported by the holding member so as to be movable back and forth and whose front end can contact the workpiece; and a contact rod that is provided between the contact rod and the holding member and which is biased by the urging force of the elastic member. After the grinding wheel head is moved forward by the grinding wheel head feeding device, and the contact rod contacts the workpiece, the contact rod is engaged with the workpiece by a larger frictional force, and then the contact rod is moved by the urging force of the elastic member during the predetermined stroke. a friction lock mechanism that integrally engages and holds the contact rod and the holding member against the grinding wheel and slides the contact rod against the holding member after a predetermined stroke; Grinding characterized by comprising: a detection switch that detects movement of the holding member with respect to the grinding wheel head; and a speed switching device that controls the grinding wheel head feeding device to switch from rapid feed to cutting feed based on a detection signal from the detection switch. Panel feed control device.