JPH0210300B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a cam device that provides a predetermined motion to an object using a cam.

[Technical background and problems]

Mechanisms that rotate a cam and give motion to an object along a predetermined shape of the cam have been built into many devices. Examples include reciprocating engines for automobiles, wire bonding equipment used in the manufacture of semiconductor devices, and various other machine tools.
The principle of the cam drive device used in these devices is as shown in FIG. An end cam 1 having a predetermined shape is supported by a rotating shaft 2, and a cam follower 3 that contacts the cam 1 is connected to a driven body 4. Furthermore, a guide 5 is provided to guide the movement of the driven body 4, and the driven body 4 and the guide 5 are connected by a spring 6, so that the cam 1 and the cam follower 3 are always in contact with each other. If the cam 1 is rotated together with the rotating shaft 2 using such a mechanism,
Via the cam follower 3 in contact with the cam 1,
The driven body 4 moves periodically according to the predetermined shape of the cam 1, that is, the cam curve.

When such a cam 1 is used to impart a predetermined movement to the driven body, it is ideal that the driven body moves along the predetermined shape of the cam 1. However, in order to perform this ideal movement, the above-described cam drive system has the following drawbacks. it is,
The cause of this is the spring 6 that keeps the cam 1 and cam follower 3 in constant contact. That is, when the cam 1 rotates and the cam follower 3 moves, the amount of extension of the spring 6 (or the amount of compression depending on the position of the attached spring 6) varies depending on the amount of movement. Accordingly, the contact pressure between the cam surface 1a and the cam follower 3 varies depending on the contact point. As a result, the amount of elastic deformation at the cam follower 3 attachment portion differs, and as a result, the driven body 4 deviates from its motion following the cam curve. Further, since the cam follower 3 is constantly in contact with the cam surface 1a and moves while sliding, friction occurs between the cam surface 1a and the cam follower 3, and wear of the cam surface 1a is unavoidable. If the contact pressure between the cam surface 1a and the cam follower 3 differs, the degree of wear of the cam surface 1a will also change as the contact pressure changes. As a result, wear increases at locations where the contact pressure is high, and the shape of the cam surface 1a itself changes. For this reason,
The driven body 4 is no longer able to perform a predetermined movement. In particular, these changes in contact pressure that have an adverse effect become noticeable when the cam 1 rotates at a high speed and the driven body 4 moves violently. Therefore, in a machine tool using a cam, the machining accuracy deteriorates, and furthermore, the cam cannot be rotated at a high speed, resulting in the inconvenience that machining efficiency cannot be improved.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a cam device that enables a driven body to perform a predetermined movement with high precision and high speed.

[Summary of the invention]

The end face cam, which is rotationally driven by the drive shaft, is
While the driven body and the second driven body are clamped at a certain position under a substantially constant pressure, these first and second driven bodies are integrally reciprocated following the rotation of the end cam. This is how it was done.

[Embodiments of the invention]

Hereinafter, a cam device according to an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 2 shows the cam device of this embodiment. This cam device includes a drive section 7 and a drive section 7.
A driven part 8 is connected to the driven part 8. The drive section 7 is composed of a rotational drive mechanism (not shown), a drive shaft 7a connected to the rotation drive mechanism and rotated in the direction of arrow A, and an end cam 9 attached to the tip of the drive shaft 7a. . The above end cam 9
has the same predetermined shape on the front surface 10 and the rear surface 11 in parallel. That is, the end cam 9 is formed so that the thickness of the drive shaft 7a in the axial direction is the same everywhere. On the other hand, the driven part 8 includes a first driven body 12 that contacts the front surface 10 and a rear surface 11.
a second driven body 13 that comes into contact with the second driven body 13; and a connecting body that connects the first driven body 12 and the second driven body 13 and urges the second driven body 13 toward the first driven body 12. 14, and a guide body 16 into which the first driven body 12 is slidably fitted in the direction of arrow 15, which is the axial direction of the drive shaft 7a. Thus, the first driven body 12 has a rectangular parallelepiped-shaped main body 17.
and a disc-shaped first rotating body 20 that is pivotally supported via a support shaft 19 in a recess 18 formed in the upper end of the main body 17 on the side of the end cam 9. A driven member (not shown) is connected to the rear end. The extension of the axis of the support shaft 19 is set to be perpendicular to the extension of the axis of the drive shaft 7a. Also, the first rotating body 2
0 partially protrudes from the recess 18 so that its outer circumferential surface abuts the lower part of the front surface 10 of the end cam 9.
Furthermore, the second driven body 13 is connected to the first driven body 12.
A main body 22 is fitted into a recess 21 formed in a main body 17 of the main body 22 so as to be slidable in the direction of arrow 15;
A disc-shaped second rotating body 25 is pivotally supported via a support shaft 24 in a recess 23 formed in a protrusion at the rear end of the end cam 9 so as to face the rear surface 11 of the end cam 9. ing. The extension line of the axis of the support shaft 24 is set to be orthogonal to the axis of the drive shaft 7a. Further, the second rotating body 25 protrudes from the recess 23 so that its outer circumferential surface abuts the lower part of the rear surface 11 of the end cam. In the recess 21, one end of the connecting body 14, which is a tension spring, is connected to the main body 22 of the second driven body 13, and the other end is connected to the innermost part of the recess 21.
The second driven body 13 is urged toward the first driven body 12 to elastically connect the two. Therefore, the end cam 9 is clamped at a fixed position at its lower end by the first and second rotating bodies 20 and 25 with a fixed pressure.

In the cam device having the above configuration, the rotation drive mechanism is activated to rotate the drive shaft 7a and the end cam 9 in the direction of arrow A. Then, the first driven body 12 in contact with the end cam 9 moves as shown by the arrow 15.
Perform reciprocating motion in the direction. That is, since the first driven body 12 and the second driven body 13 are integrally connected by the connecting body 14, the first and second rotating bodies clamp the end cam 9 at a fixed position. 20,2
5, it moves following the movement of the end face cam 9. At this time, since the end cam 9 is formed to have the same thickness everywhere, the distance between the first and second rotating bodies 20 and 25 is always constant. Therefore, the length of the connecting body 14 is also constant, and the contact pressure between the first and second rotary bodies 20, 25 is always maintained constant. Furthermore, when the end cam 9 rotates at high speed, larger vibrations occur than when it rotates at low speed, but since the generated vibrations are absorbed by the connecting body 14, there is no deterioration in cam performance. Therefore, the problem that the movement of the first driven body 12 deviates from a predetermined cam curve due to a change in contact pressure, or that the amount of wear locally increases and the cam shape itself changes is solved. In particular, since the connecting body 14 is elastically expandable, the first and second rotating bodies 2
Compared to the case where the distance between the first and second rotary bodies 20 and 25 is fixedly provided, there is no need to adjust the distance between the first and second rotary bodies 20 and 25, which facilitates maintenance and improves durability. Not only that, even if the first and second rotating bodies 20 and 25 are worn out, the length of the connecting body 14 changes depending on the amount of wear, so that the first and second rotating bodies 20 and 25 are Compared to the case where the interval between the first and second rotating bodies 20 and 25 is fixedly provided, problems such as play occurs and the accuracy of the cam movement decreases, and the interval between the first and second rotating bodies 20 and 25 is forced to be adjusted again. disappears. In addition, the end cam 9
first and second rotating bodies 20 that are in contact with and interlock with each other;
Front surface 10 and rear surface 1 of the end surface cam 9 on the outer peripheral surface of 25
1, the first and second rotating bodies 2
Since the rotational directions of 0 and 25 are set to match the rotational direction of the end cam 9, the first and second driven bodies 12 and 13 follow the end cam 9 smoothly and without difficulty. Therefore, this and the aforementioned two effects of the first and second rotating bodies 20 and 25 clamping the end cam 9 at a constant pressure and at a constant position combine to produce the first effect. The driven body 12 can move at high speed and with high precision.

Although the connecting body 14 in the above embodiment uses a tension spring, a pneumatic cylinder capable of elastic support may also be used. Further, in the above embodiment, the front surface 10 and the rear surface 11 of the end cam 9 are parallel, but only the portions where the first and second rotating bodies 20 and 25 contact are parallel, that is, if the thicknesses are equal, the shape is not restricted.

〔Effect of the invention〕

As described above, the cam device of the present invention is capable of following the end cam of the driven member at high speed and with high precision. Therefore, when this device is applied to, for example, a machine tool using a cam drive, highly efficient machining becomes possible and machining accuracy improves.

[Brief explanation of drawings]

Figure 1 is a front view showing the main parts of a conventional cam device;
FIG. 2 is a front view of a cam device according to an embodiment of the present invention. 7a... Drive shaft, 9... End cam, 12... First driven body, 13... Second driven body, 14... Connecting body, 16... Guide body, 20... First rotating body ,
25...Second rotating body.

Claims (1)

[Claims] 1. A drive shaft rotatably driven around an axis, a plate-shaped end cam attached to one end of the drive shaft, and a first rotating body whose outer peripheral portion abuts one end surface of the end cam. a first driven body rotatably provided following the rotation of the end cam;
A disk-shaped second rotary body is supported by the driven body so as to be able to move back and forth in a direction parallel to the axis of the drive shaft, and whose outer peripheral portion abuts the other end surface of the end cam. A second driven body rotatably provided to follow the first driven body, and the first driven body and the second driven body are elastically connected to each other, and the first driven body and the second driven body are connected to each other. a connecting body that clamps the end cam, and a guide body that supports the first driven body so as to be movable back and forth in a direction parallel to the axis of the drive shaft; A cam device characterized in that a portion clamped by the rotary body and the second rotary body has substantially the same thickness so that the rotating end face cam is elastically clamped with a substantially constant pressure.