JPS63111359A - Cam device - Google Patents

Abstract

PURPOSE:To restrain the abrasion of contact parts of a follower, and outer and inner cams, by providing the outer cam and inner cam which make contact with the follower may be rotated in opposite directions with respect to each other even though the follower make into contact with both outer and inner cams, simultaneously. CONSTITUTION:There are provided outer and inner cams 13, 15 which are rotated at an equal angular speed in opposite directions with respect to each other about one and the same rotating center O. If the distance R of the contour curve of the outer cam 13 from the rotating center O may be exhibited by the formula R=f(theta) where theta is an included angle at the rotating center O, the distant (r) of the contour curve of the inner cam 14 from the rotating center O may be exhibited by the formula r=f(-theta)-d, the minimum value of the distance R being made to be greater than the maximum value of the distance (r). Further, the follower 16 has a diameter less than (d) and may fitted in between the outer and inner cams 13, 14. With this arrangement, it is possible to restrain the abrasion of the contact parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cam device comprising a cam and a follower driven by the cam.

[Conventional technology]

Conventionally, it was used as a cam device to accurately trace the follower along the pitch curve of the cam.

A so-called front cam, as shown in FIG. 4, is used. In other words, pitch curve 1 in which the distance from the center of one rotation changes
A cam 3 having a cam groove 2 of a constant width formed on its flat front surface is used, and a follower 6 is fitted into the cam groove 2 so as to be freely movable.

In this cam device, since the follower 6 is fitted into the cam groove 2, the follower 6 does not deviate greatly from the contour curve of the cam that forms the cam groove 2.

Compared to so-called planar cams, end face cams, etc. that do not have cam grooves 2, the pitch curve 1 at the center can be traced more accurately.

[Problem that the invention seeks to solve]

However, in this conventional cam device, since both the inner and outer contour curves forming the cam groove 2 rotate in the same direction, when the follower 6 touches the inner contour curve of the cam groove 2, Rotational forces are applied in opposite directions when touching the contour curve. Therefore, unless a sufficient margin is provided between the cam groove 2 and the follower 6, the follower 6 will not rotate smoothly and travel.

However, if a margin is provided between the cam groove 2 and the follower 6, as shown in FIG. The pinch curve 1 is not accurately traced.

Moreover, since the follower 6 is rotated in opposite directions each time it comes into contact with the outer contour curve and the inner contour curve of the cam groove 2, the follower 6 is rapidly worn out when the cam 3 rotates at high speed.

This invention aims to solve the above-mentioned problems in conventional cam devices.

[Means to solve the problem] Referring to the symbols shown in Figures 1 and 3.

To explain the structure of this invention, the cam consists of an outer cam 13 and an inner cam 14 that rotate in opposite directions about the same rotation center 0 at a constant angular velocity. The distance #R of the contour curve of the outer cam 13 from the rotation center O is.

When expressed as R=f (θ) with respect to the angle θ sandwiching the rotation center 0, the distance r of the contour curve of the inner cam 13 from the rotation center 0 is expressed as r=f(−θ)−d with respect to the above angle θ.
It is expressed by the formula. Moreover, the minimum value Rmin of the former distance R
is set to be greater than or equal to the maximum value rllax of the latter distance r.

The follower 16 has a diameter equal to or less than the above d, and is fitted between the outer cam 13 and the inner cam 14.

[For production]

When the outer cam 13 and the inner cam 14 are rotated relative to each other around the rotation center, there will always be a point where the distance R-r between the contour curves of the two is equal to d during one rotation.
There are more than one place. For example, as shown in Fig. 1, this position is set directly above the 8 rotation center O, and the outer cam 13 and the inner cam 14 are moved in opposite directions around the rotation center 0 with a constant angular velocity ω. When rotated, the rotation center 0 of the contour curve of the outer cam 13 and the inner cam 14 immediately above the rotation center O
The distances R and r from are R=f with respect to time t, respectively.
(ωt), r=f (ωt)−d.

That is, the distances MR and r of the contour curve here change with the passage of 2 hours t, but the interval between them is R-r=d
(constant).

Therefore, a follower 1 with a diameter of d or less is placed between the outer cam 13 and the inner cam 14 at a location directly above the rotation center O.
By fitting the follower 16 into the cam 1,
3. Move up and down to trace the middle of 14.

At this time, the follower 16 is connected to the outer cam 13 and the inner cam 14.
Since the outer cam 13 and the inner cam 14, which contact the follower 16 from above and below, rotate in opposite directions, the follower 16 rotates in a constant direction and hardly slides against the 1 contour curve. , makes complete rolling contact. Therefore.

The diameter of the follower 16 is determined by the distance d at the point where R-r=d above.
As long as the cam groove 12 is close to the
3 and the inner cam 14.

Furthermore, since the minimum value Rmin of the distance R from the rotation center O of the contour curve of the outer cam 13 to be formed is greater than or equal to the maximum value r max of the distance r from the rotation center of the contour curve of the inner cam 14, the outer cam 13 and the inner cam 14 do not interfere with each other during nine rotations.

〔Example〕

Next, an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows the front shapes of the outer cam 13 and the inner cam 14, and the outer cam 13 and the inner cam 14 are
They are rotatably supported around the same rotation center O.

As already mentioned, when the distance R of the contour curve of the outer cam 13 from the rotation center 0 is expressed by the formula R=f(θ) regarding the angle θ between the rotation center 0, the contour of the inner cam 14 The distance r of the curve from the rotation center 0 is expressed by the equation r=f(-θ) regarding the angle θ. Also, what is the minimum value Rmin of the distance R and the maximum value rmax of the distance r?

Rmin≧rmax.

The outer cam 13 and the inner cam 14 are connected to the rotation center O
, and find a point where R-r=d, and fit the follower 16 of the driven joint 15 there. The follower 16 should be a roller type that can rotate once, and its diameter should be as close as possible to the above-mentioned d. However, thermal expansion of corner components.

In practice, it is common to allow some margin for fitting, taking into account errors and the like. In addition, in FIG. 1, 15 is
This is a driven link connected to the follower 16.

In this state, the outer cam 13 and the inner cam 14 are rotated at equal angular speeds in opposite directions. FIG. 2 shows an example of the operating curve of the follower 16 in this case.

By providing almost no clearance between the cam groove 12 and the follower 16, the movement of the follower 16 hardly occurs at a location where the direction of movement of the follower 16 changes.

Next, FIG. 3 shows a rotation transmission mechanism using a gear train as an example of a mechanism for rotating the outer cam 13 and the inner cam 14. That is, the rotation of the drive shaft 19 is transmitted in the opposite direction to the inner cam 14 via the planetary gear mechanism 20, and the rotation of the drive shaft 19 is transmitted via the gear trains 21 and 22 and the gear trains 23 and 24. , is transmitted to the outer cam 13 in the positive direction.

In this case, it goes without saying that the gear ratio of the square gear train is selected so that the rotation of the HA dynamic shaft 19 is transmitted to the inner cam 14 and the outer cam 13 at the same ratio.

The transmission mechanism from the drive shaft 19 to the outer cam 13 and the inner cam 14 includes not only a gear train, but also a winding electric mechanism using a sprocket and sprocket foil, or a belt and pulley.

Alternatively, a combination of these can be used.

〔Effect of the invention〕

As explained above, according to the present invention, the follower 1
6 can be ensured, the follower 16 does not move around in the cams 13 and 14, and these cams 1
Also follows precisely along the contour curves of 3 and 14. While the follower 16 rotates in a fixed direction, it completely rolls into contact with both the outer cam 13 and the inner cam 14, so that the follower 16. Outer cam 13, inner cam 1
Wear of the contact portions of No. 4 can be minimized.

[Brief explanation of the drawing]

FIG. 1 is a contour view of a cam showing an embodiment of the present invention, and FIG.
The figure is a graph showing the operating curve of the follower 16 in the same embodiment, FIG. 3 is a gear engagement diagram showing an example of the cam driving force transmission mechanism in the same embodiment, and FIG. 4 is a conventional example of the cam. The contour diagram, FIG. 5, is a graph showing the motion curve of the follower 16 of the same cam. 13--Outer cam 14--Inner cam 16- Follower Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5

Claims (1)

[Claims] A cam mechanism consisting of a cam and a follower that follows this contour curve, including an outer cam 13 and an inner cam 14 that rotate in opposite directions about the same rotation center O at a constant angular velocity,
Distance R of the contour curve of the outer cam 13 from the rotation center O
is expressed by the formula R=f(θ) with respect to the angle θ between the rotation center O, then the distance r from the rotation center O of the contour curve forming the cam groove 12 of the inner cam 13 is equal to the angle θ is expressed by the formula r=f(-θ)-d, and the minimum value Rmin of the former distance R is the maximum value rma of the latter distance r.
A cam device characterized in that a follower 16 having a diameter of x or more and a diameter of d or less is fitted between these contour curves.