JPH0248390B2 - KAMUKENSAKUBAN - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cam grinding machine used for machining a workpiece having a plurality of cam pieces having different phases, such as an engine valve camshaft.

Conventionally, this type of grinding machine is equipped with a work shaft for rotating a work on a swing table, and the swing of the swing table is controlled by a master cam that rotates in synchronization with the work shaft, and the swing direction of the table is controlled by a master cam that rotates in synchronization with the work shaft. It is known that a workpiece is ground using a rotating grindstone at the front, but in this case, when processing a workpiece that has multiple cam pieces with different phases, multiple cam pieces are ground in the axial direction with a phase corresponding to each of these cam pieces. It is common practice to use a master cam with two cam parts arranged side by side, and to grind the cam pieces one by one by sequentially contacting these cam parts with a touch roller that cooperates with the master cam. As the dimensions increase, it becomes necessary to support the master cam at both ends to prevent it from deflecting, and when replacing the master cam, it is necessary to disassemble the bearing members at both ends, making the replacement work troublesome. There are also known models that can move forward and backward in the axial direction, allowing the master cam to be replaced (Utility Model Publication No. 55-26618).
This has the disadvantage of requiring a complicated mechanism for moving the bearing member forward and backward.

In view of the above points, an object of the present invention is to provide a cam grinding machine in which the axial dimension of the master cam is shortened, the master cam can be supported in a cantilevered state, and the master cam can be easily attached and detached. It is said that

In order to achieve this object, the present invention includes a work shaft for rotating a work on a swing table, a touch roller on one side of the swing table and a machine frame outside the swing table, and a touch roller on the other side of the work shaft. A master cam that rotates in synchronization with the shaft is provided, the touch roller is brought into contact with a cam portion formed on the master cam, and the swing table is swung to follow the cam portion,
In the device in which the cam pieces of the workpiece are ground by a rotary grindstone placed on one side of the swinging direction of the swinging table, the plurality of cam pieces of the workpiece are divided into groups according to shape, and one cam part is cut for each group. A shift means is formed on the master cam to selectively move the touch roller to a position facing each cam portion of the master cam, and the rotational phase of a cam shaft on which the master cam is mounted relative to the work shaft can be freely adjusted. The master cam was detachably attached in the axial direction to the free end of the camshaft that protruded in that direction from the shaft bearing.

By making the rotational phase of the camshaft relative to the workpiece shaft adjustable, when grinding each cam piece of the workpiece, the phase of the cam part of the master cam can be adjusted to match the phase of this cam piece. One common cam part can be used for a plurality of cam pieces having different values. Therefore, the master cam has
1 each for each shape without considering the phase difference of the cam piece.
The number of cam parts can be made smaller than the number of cam pieces of the workpiece, and a master cam with a small axial dimension can be used as the master cam. Therefore, even if the master cam is attached to the free end of the camshaft and supported in a cantilevered state, the deflection of the master cam is suppressed to a minute amount, and deterioration in machining accuracy due to the deflection of the master cam does not occur.

Next, the present invention will be explained with reference to the illustrated embodiments.

The drawing shows an embodiment in which a valve camshaft of a two-cylinder engine is used as a workpiece W, and each pair of intake valve cam pieces wa, wa' and exhaust valve cam pieces wb, wb' of the workpiece W are ground. 1 in the figure is a swinging table equipped with a workpiece shaft 2 that rotates a workpiece W. The table 1 is provided so as to be able to swing back and forth about a fulcrum shown by X in FIG. is swung forward by the bullet machine 3, and the workpiece w comes into contact with the rotary grindstone 4 in front of it, and the touch roller 6 and master cam 7, which are disposed facing each other between the table 1 and the machine frame 5 in front of it, is configured to cause abutment.

It is optional whether the master cam 7 is placed on the table 1 or the machine frame 5, but in the illustrated example, the master cam 7 is attached to the cam shaft 8 and placed on the machine frame 5.
The touch roller 6 was moved in the axial direction by a shift means 9 consisting of a cylinder coaxially with the work shaft 2.

According to the present invention, the camshaft 8 is configured such that its rotational phase can be freely adjusted with respect to the workpiece shaft 2.This will be described in more detail with reference to the one shown in the drawings. , a master cam drive motor 1 separate from the work drive motor 10 that rotationally drives the work shaft 2.
1, and both motors 10 and 11 are rotated by drive pulses from a control device (not shown).
The work shaft 2 and the cam shaft 8 are driven synchronously to rotate the work shaft 2 and the cam shaft 8 synchronously, and the rotation phase of the cam shaft 8 with respect to the work shaft 2 is adjusted by driving only the master cam drive motor 11. .

Here, the master cam 7 is a cam piece for an intake valve.
A pair of cam parts having different shapes, a first cam part 7a shared by the exhaust valve cam pieces wb and wb', and a second cam part 7b shared by the exhaust valve cam pieces wb and wb' are arranged in the axial direction. Bearing 1 is installed in machine frame 5.
The free end 8a of the camshaft 8 protrudes outward from the camshaft 8.
It can be attached and detached in the axial direction. To explain this in more detail, the master cam 7 has a joint 13 which is made up of unevenness formed on the end face of the free end 8a and unevenness formed on the axial end face of the master cam 7, as shown clearly in FIG. The camshaft 8a is engaged with the free end 8a in a non-rotative manner and fixed thereto by a locking means, and the locking means is, for example, a substantially T-shaped lock that extends through the camshaft 8 and protrudes outward. The locking piece 14a is inserted into the square hole 7c at the center of the master cam 7 as shown in FIG. The master cam 7 is engaged and fixed to the free end 8a via the locking piece 14a by rotating the rod 16 by 60° and moving it backward in the drawing. When the engagement piece 14a is released from the master cam 7 and the rod 14 is reversed, the locking piece 14a aligns with the square hole 7c, allowing the master cam 7 to be removed in the axial direction. The camshaft 8 is connected to the master cam drive motor 11 via a belt 17 at a timing pulley 8b at its root.

In the drawing, reference numeral 18 indicates a storage device for the master cam 7 provided on the side of the camshaft 8.
The upper master cam 7 and the master cam 7 on the cam shaft 8
The storage device 18 can be freely exchanged via an intermediate exchange device 19. To explain this in more detail, the stock device 18 has a plurality of master cams 7 arranged at intervals in the circumferential direction, as shown in FIG. The exchange device 19 is equipped with a rotating frame 19a that can move forward and backward in the axial direction, and a pair of clamp members 19b, 19b. Master cam 7 has been moved to a predetermined index position with
and the master cam 7 on the camshaft 8 are grasped by the respective clamp members 19b, 19b, and the index table 18a and the camshaft are moved by moving the rotating frame 19a toward the receiving side in FIG. After separating from the master cam 8, the master cam 7 is replaced by rotating the rotating frame 19a by half a turn and moving it to the left.

Incidentally, the rotation frame 19a is provided with a positioning pin 19c that engages the peripheral surface of the master cam 7 with the notch 7d to match the phase thereof.

In the drawing, 18b is a drive motor for the index table 18a, 19d is a cylinder for advancing and retracting the rotation frame 19a, and 19e is a rack cylinder for rotation thereof.

Next, to explain the grinding process of the workpiece w according to the present invention, first, the rotary grindstone 4 is moved to a position facing the left intake valve cam piece wa, and the touch roller 6 is moved to a position facing the first cam part 7a of the master cam 7. According to this, the cam piece wa is moved forward to swing the swing table 1 forward.
A cut of a predetermined depth is made by the rotary grindstone 4 at a predetermined portion of the cam portion 7a, and the touch roller 6 cuts into the cam portion 7a.
, and then the work shaft 2 and the cam shaft 8
The cam piece wa is ground into a cam shape corresponding to the cam part 7a by the oscillation of the table 1 following the cam part 7a.

After the grinding is completed, the table 1 is swung backwards and the exhaust valve cam piece to be ground next is attached to the rotary grindstone 4.
wb, and the touch roller 6 is moved to a position facing the second cam portion 7b of the master cam 7, and then the table 1 swings forward, as described above. By the same operation, the cam piece wb is ground into a shape corresponding to the cam portion 7b.

As described above, one set of cam pieces for intake valves and exhaust valves
Grinding of wa and wb is performed, but the cam pieces wa′ and wb′ for the next intake valve and exhaust valve have a phase difference of 180° with respect to the former, so the camshaft 8 is ground to the work shaft 2. On the other hand, after rotating 180 degrees to adjust the phase, the cam pieces wa' and wb' are ground by the same operation as described above.

Here, in the conventional one, a master cam is used which has four cam parts, which is the same number as the number of cam pieces on the workpiece w, whereas according to the present invention, two cam parts 7 are used.
Each cam piece wa, with master cam 7 having a, 7b,
It is possible to grind wb, wa', wb', and the axial dimension of the master cam 7 is shortened to about half compared to the conventional one, and even if it is supported in a cantilevered state as described above, its deflection is suppressed to a very small amount and does not cause any deviation in grinding.

When replacing the master cam 7, the engagement of the master cam 7 with the cam shaft 8 is released as described above, and the master cam 7 is replaced with a predetermined master cam 7 provided in the stock device 18 via the replacement device 19.

As described above, according to the present invention, by making the rotational phase of the camshaft relative to the work shaft adjustable, it is possible to use a master cam with a reduced number of cam parts and a short axial dimension.
This enables the master cam to be attached to the free end of the camshaft and supported in a cantilevered state, and thus the master cam can be easily removed from the free end of the camshaft in the axial direction outward, and its attachment/detachment is easy. It has the effect of making it easier.

[Brief explanation of drawings]

FIG. 1 is a plan view of an example of an embodiment of the present invention, FIG. 2 is a side view of the master cam exchange mechanism seen from the - line in FIG. , FIG. 4 is a side view taken from the - line in FIG. 3, and FIG. 5 is a line diagram showing the swinging mechanism of the swinging table. 1... Swing table, 2... Work axis, 4...
Rotating grindstone, 7...Master cam, 8...Cam shaft, 8
a...Free end, 9...Shifting means, 12...Bearing.

Claims (1)

[Claims] 1 A cam grinding machine that processes a workpiece having a plurality of cam pieces with different phases, which is equipped with a work shaft for rotating the workpiece on a swinging table, and a machine external to the swinging table and the swinging table. A touch roller is provided on one side of the frame, and a master cam that rotates in synchronization with the work shaft is provided on the other side, and the touch roller is brought into contact with a cam portion formed on the master cam so that the swing table follows the cam portion. In a device in which the cam pieces of the workpiece are ground by a rotary grindstone placed on one side of the swinging table in the swinging direction, the plurality of cam pieces on the workpiece are divided into groups according to shape, and one piece is prepared for each group. cam portions are formed on the master cam, a shift means is provided for selectively moving the touch roller to a position facing each cam portion of the master cam, and a rotational phase of a cam shaft on which the master cam is mounted relative to the work shaft is adjusted. A cam grinding machine characterized in that the master cam is detachably attached in the axial direction to the free end of the camshaft that protrudes outward from a camshaft bearing.