JPH01193455A - Vibration generator - Google Patents

Abstract

PURPOSE:To set at will the patterns of angular speed and angular acceleration by forming a cam surface of a first cam surface for guiding a cam follower apart from a rotary drive shaft and a second cam surface for guiding the cam follower toward the rotary drive shaft. CONSTITUTION:A cam follower 3 adapted to slidably contact a cam surface C by a press means 6 rolls alternatively on first and second cam surfaces C1 and C2 as a cam 5 is rotated, while reciprocating thrice every rotation of the cam 5 to the rotary drive shaft 4 with a stroke of about height difference between top and bottom portions 5a, 5b. When the rotational speed of rotary drive shaft 4 is made constant in the reciprocation, changes in the swing angle of a swing shaft 2, angular speed and acceleration in the passage of time depend upon the contour of cam surface C. Thus, any various swing configuration can be realized by changing the profiles of first or second cam surface C1, C2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a vibration generating device, and particularly to a vibration generating device suitable for use in a vibration testing machine.

[Prior Art] Conventionally, as an example of a vibration generating device, one using a crank mechanism has been proposed.

A swing generating device using this crank mechanism has one end of the connecting rod rotatably attached to the crankshaft at a position radially apart from its rotation center, and the other end of the connecting rod attached to the swing shaft. It has a structure in which it is rotatably attached at a position spaced apart in the radial direction from the center of swing.

The rotational motion of the crankshaft is converted into reciprocating motion of the connecting rod, and the reciprocating motion of the connecting rod is further converted into the rocking motion of the swing shaft.

[Problems to be Solved by the Invention] By the way, in the swing generator having the above-mentioned configuration, by changing the length of the connecting rod, it is possible to change the swing angle of the swing shaft and the accompanying angular velocity and angular acceleration. The adjustment range is limited to the extent that changes can be made, and the change pattern of these angular velocities and angular accelerations can only be obtained if they are uniform.
It is desired to have a configuration that allows these change patterns to be changed as appropriate.

The present invention aims to solve these problems.

[Means for Solving the Problems] A first aspect of the present invention for solving the above-mentioned problems is as follows:
a swing shaft, a cam follower provided on the swing shaft at a distance from the center of swing in the swing radius direction, a rotary drive shaft provided along the swing shaft, and a cam follower integrated with the rotary drive shaft. A cam attached to the cam and rotated in a plane parallel to a moving surface of the cam follower, and a cam connected to the swing shaft to constantly maintain the cam follower and a cam surface formed on the outer periphery of the cam in contact with each other. The cam surface includes a first cam surface that guides the cam follower in a direction away from the rotation drive shaft, and a second cam surface that guides the cam follower in a direction toward the rotation drive shaft. and a cam surface, and the pressing means is a spring.

Further, a second aspect of the present invention provides cam followers provided on the swing shaft at two positions spaced apart from the center of swing in the radial direction of the swing and in the direction of swing, and both of these cam followers. a pair of rotary drive shafts provided along the rocking shaft, a cam having a cam surface integrally provided on each of these rotary drive shafts and slidably contacting each of the cam followers; a drive mechanism provided between the two rotary drive shafts to rotate them synchronously, and a cam surface formed on each of the cams is a first cam that guides each of the cam followers in a direction to separate them from the rotary drive shaft. and a second cam surface that guides the cam follower in a direction approaching the rotational drive shaft, and the cam follower is in contact with the first cam surface of one of the cams. In this case, the relative positional relationship is set so that the cam follower is brought into contact with the second cam surface of the other cam, and the rotation directions of the two rotary drive shafts are opposite directions. This also includes that the directions of rotation of both rotational drive shafts are the same.

Further, a third aspect of the present invention provides a cam follower provided on the swing shaft at a position spaced apart from the center of swing in the swing radial direction, and a cam follower provided on both sides of the cam follower along the swing shaft. a pair of rotary drive shafts provided at the same time; a cam having a cam surface that is integrally provided on each of these rotary drive shafts and slidably contacts each of the cam followers from both sides in the swinging direction; and a cam between the two rotary drive shafts. a first cam surface that guides each cam follower in a direction that separates the cam follower from the rotational drive shaft; and a second cam surface that guides the cam in a direction approaching the rotational drive shaft, and when the cam follower is in contact with the first cam surface of one cam, the second cam surface The relative positional relationship is set such that the cam follower is brought into contact with the second cam surface of the cam, and the rotational directions of both rotational drive shafts are opposite directions, and This includes that both rotational drive shafts rotate in the same direction.

[Operation] According to the present invention, by changing the profile of the first or second cam surface of the cam, the moving speed of the cam follower guided thereby can be changed, and the pattern of angular velocity or angular acceleration can be set arbitrarily. enable. Furthermore, in particular, according to the second and third aspects, a pressing force is constantly applied to the cam follower by the pair of cams to generate a large angular acceleration.

Example] The first aspect of the present invention will be described below with reference to FIGS. 1 and 2.
An explanation will be given based on an example shown in the figure.

In the figure, reference numeral 1 indicates a rocking device according to the present embodiment, which includes a rocking shaft 2, a cam follower 3 provided on the rocking shaft 2 at a distance from the rocking center 01 in the rocking radial direction, A rotation drive shaft 4 provided along the swing axis O4, a cam 5 that is integrally attached to the rotation drive shaft 4 and rotated in a plane parallel to the movement plane of the cam follower 3, and the swing shaft. a suppression means 6 connected to the cam follower 3 and a cam surface C formed on the outer periphery of the cam 5 to keep the cam follower 3 and a cam surface C formed on the outer periphery of the cam 5 in constant contact; It has a configuration formed by a first cam surface C3 that guides the cam follower 3 in a direction away from the rotation drive shaft 4, and a second cam surface Ct that guides the cam follower 3 in a direction toward the rotation drive shaft 4. .

Next, to explain these details, the swing shaft 2 is swingably attached to a substrate (path shown in the figure);
As shown in FIG. 1, a disk 7 is integrally and concentrically attached to the end of the disk 7, and the cam follower 3 is attached near the peripheral edge of the disk 7.

The cam follower 3 is constituted by a rolling element rotatably supported by the disc 7.

The rotary drive shaft 4 is disposed near the disk 7 in parallel to the swing shaft 2, and is rotatably supported by the substrate. The rotary drive shaft 4 is connected with a drive mechanism (path shown) that rotates the rotary drive shaft 4 in one direction (clockwise in the illustrated example).

The cam 5 attached to this rotary drive shaft 4 is
As shown in the figure, the profile has top portions 5a formed at three locations spaced at a predetermined pitch in the rotational direction, and a bottom portion 5b formed in the middle of these top portions 5a.

The top portion 5a and the bottom portion 5b are continuous by a gentle curve, and the outer peripheral edge thereof is the cam surface C.

Furthermore, in this embodiment, the front side of the cam 5 in the rotation direction of the cam 5 is the first cam surface C1, and the rear side of the top portion 5a in the rotation direction is the second cam surface C7.

Therefore, as the cam 5 rotates, the cam follower 3 that is brought into sliding contact with the cam surface C comes into contact with the first cam surface C7 and the second cam surface C7.
The top portion 5a and the bottom portion 5 are alternately rolled on the cam surface C2 of the rotary drive shaft 4.
The height difference between the cam 5 and the cam 5 is defined as a stroke, and the cam 5 can make three reciprocations per revolution.

On the other hand, the shape of the cam surface C is between the center of the cam follower 3 and the center of the rotational drive shaft 4. When the distance from Ll is set to satisfy the following equation.

L + = A + M X S i n (3θ) However, A; Reference circle of cam 5, M: Distance between the top part 5a and bottom part 5b and the reference circle θ; Angle around rotational drive shaft 4; are shown respectively.

Furthermore, the distance between the cam follower 3 and the swing axis of the swing shaft 2 is the distance L3 between the swing center 01 of the swing shaft 2 and the center O3 of the rotary drive shaft 4, and the center of the cam follower 3. The relationship between the distance ML and the center 02 of the rotary drive shaft 4 is set so as to satisfy the following equation.

L+ + Lt > L3 In this embodiment, a coil spring is used as the suppressing means 6, and a connecting arm 8 protruding from the substrate and the disk 7 is used as the suppressing means 6.
The disc 7 is suspended in one direction so as to press the cam follower 3 toward the cam 5.

Thus, the swing generating device l of the present embodiment configured as described above rotates the rotary drive shaft 4 in a predetermined direction at a constant speed, and the cam 5 attached to the rotary drive shaft 4 generates a cam follower. 3 by repeating the operation of moving it against the elastic force of the pressing means 6 and the operation of moving it in the opposite direction by the elastic force of the pressing means 6.
reciprocate within a predetermined angle range.

When such a rocking operation is viewed as the rocking angle, angular velocity, and angular acceleration of the rocking shaft 2 relative to the rotation angle of the cam 5, it becomes as shown in FIG. 2.

In FIG. 2, curve 1 shows the swing angle, curve C shows the angular velocity, and curve C shows the angular acceleration.

Note that the conditions at this time are as follows.

A = 40mm, M = 8mm, Ly = 5
0 mm, L3 = 70 mm, and rotation speed N of the rotary drive shaft 4 = 100 Or p m.

Moreover, since the cam follower 3 is constantly in contact with the cam surface C of the cam 5 during this rocking operation,
When the rotational speed of the rotary drive shaft 4 is constant, temporal changes in the rocking angle of the rocking shaft 2, and temporal changes in the angular velocity and angular acceleration depend on the shape of the cam surface C. .

Therefore, by changing the shape of this cam surface C, that is, the profile of the cam 5, various arbitrary swing shapes can be realized.

Next, an embodiment related to the second aspect of the present invention will be described in the third embodiment.
This will be explained based on the drawings to FIG.

Reference numeral 10 in FIGS. 3 and 4 indicates a swing generating device according to the present embodiment, which is attached to the swing shaft 11 at a distance L2 in the swing radius direction from the swing center and at a predetermined distance in the swing direction. Angle α
Cam followers 12 (12a
12b), a pair of rotary drive shafts 13 (13a and 13b) provided along the swing shaft 11 on both sides of these cam followers 12, and these rotary drive shafts 1
3, each of the cam followers 12
A cam 14 (14a/
14b) and a drive mechanism 15 that is provided between the two rotary drive sleeves 13 and rotates them synchronously, and the cam surface C formed on each of the cams I4
It is formed by a first cam surface CI that guides the cam follower 12 in a direction away from the rotational drive shaft, and a second cam surface C2 that guides the cam follower 12 in a direction that approaches the rotational drive shaft, and both cams 14 is such that when one cam follower 12a is in contact with the first cam surface C3 of one cam 14a, the other cam follower 12b is in contact with the second cam surface C2 of the other cam 14b. The configuration is such that relative positional relationships are set.

To explain these details, the swing shaft 11 is as follows:
As shown in FIG. 4, it is swingably supported by a base body 16, and a pair of disks 17 are arranged concentrically and spaced apart from each other in the longitudinal direction of the swing shaft 11 in the longitudinally intermediate portion thereof. The two cam followers 1 are provided integrally with each other between these discs 17.
2 (12a, 12b) are attached.

Both ends of these cam followers 12 (12a-12b) are rotatably supported by bearings 18 attached to each of the disks 17. This is a configuration taken in order to make the outer diameter of the contact portion of the cam follower 12 with the cam 14 as small as possible, while being able to withstand a large load.

Each of the cams 14 is integrally fixed to each of the rotary drive shafts 13 by a clamp 19.

In this embodiment, as shown in FIG. 3, top portions T are formed at two locations spaced apart by a predetermined pitch in the rotational direction, and - a bottom portion B is formed in the middle of these top portions T. It is said that the profile has been created.

These top portions T and bottom portions B are continuous by a gentle curve, and the outer peripheral edge thereof is the cam surface C.

Further, the side toward the top of the top portion T in the rotational direction of the cam 14 is a first cam surface C4, and the rear side in the rotational direction is a second cam surface C.

Therefore, the cam follower 12 that is brought into sliding contact with the cam surface C is moved alternately on the first cam surface C4 and the second cam surface C7 as the cam 14 rotates, and
With respect to the rotary drive shaft 13, the cam 14 is made to reciprocate twice per rotation, with the difference in height between the top portion T and the bottom portion B being defined as a stroke.

On the other hand, the shape of the cam surface C is set so as to satisfy the following equation, where Ll is the distance between the center of the cam follower 12 and the center 02 of the rotary drive shaft 13.

L, -A+MXS i n (2θ) however, A: Reference circle of cam 5, M: Distance between top part T and bottom part B and reference circle θ1 rotation Angle around drive shaft 4: are shown respectively.

Further, the distance between the cam follower 12 and the swing center O1 of the swing shaft 11 is the distance ML3 between the swing center 0 of the swing shaft 11 and the center 02 of the rotary drive shaft 13, and the distance ML3 between the swing center 0 of the swing shaft 11 and the center 02 of the rotation drive shaft 13, The relationship between the distance L1 between the center of the rotary drive shaft 13 and the center Of of the rotary drive shaft 13 is set so as to satisfy the following equation.

1 + + l t > L 3 As shown in FIG. 4, the drive mechanism 15 includes driven gears 20 attached to each of the rotational drive shafts 13, and an idle gear 21 meshed with each of these driven gears 20, It is constituted by a belt type power transmission mechanism 24 provided between an input shaft 22 to which one idle gear 21 is attached and an output shaft 23 of a drive motor.

Therefore, with this drive mechanism 15, each rotary drive shaft 1
3 and the cam 14 are designed to be rotated in opposite directions, and when a large change in load occurs on the swing shaft 11, the load may be reduced due to slipping of the belt in the belt-type power transmission mechanism 24, etc. It is designed to absorb fluctuations.

On the other hand, as shown in FIG. 7, the other components except for the belt-type power transmission mechanism 24 are housed in a sealed case 25 and immersed in oil to lubricate rotating parts, sliding parts, or transfer parts. At the same time, overheating is prevented by guiding this oil to an external radiator (path shown) and exchanging heat with outside air.

Furthermore, one end of the swing shaft 11 is connected to the closed case 2.
5 and protrudes to the outside, and the protruding end thereof is connected to a sample mounting plate 27 in a device 26 such as an environmental tester. And this device 26
Considering that the connector is used at high temperatures, a heat insulating material 28 is provided at the connecting portion.

Next, the operation of this embodiment will be explained.

First, from the position shown in FIG. 3, the drive mechanism 13 rotates both rotary drive shafts 13 in opposite directions (one rotary drive shaft 13a clockwise and the other counterclockwise) at a constant speed. , one cam follower 12a is connected to the other cam 1.
The rotational drive I[1113a
This movement continues until the cam follower 12a reaches the top portion T of the cam 14.

On the other hand, the cam follower 12b that is in contact with the other cam 14b is caused by the second cam 14b being rotated in the opposite direction in synchronization with the one cam 14a. It is guided by the cam surface C1 toward the other rotational drive shaft 13b, and this movement continues until the cam follower 12b reaches the bottom portion B of the other cam 14b.

This operation causes the swing shaft 11 to swing from the maximum clockwise swing position to the maximum counterclockwise swing position in FIG. 3.

When both cams 14 continue one rotation further, contrary to the above, the other cam follower 12b is moved by the first cam surface C1 of the other cam 14b to the other rotational drive shaft 13.
b, and one cam follower 12a is guided in a direction approaching one rotary drive shaft 13a by the second cam surface C2 of one cam 14a, thereby causing the swinging The shaft 11 is swung clockwise.

Thereafter, the swing shaft 11 is caused to swing at a rate of two reciprocations per rotation of both cams 14.

In addition, during this rocking operation, the rocking of the rocking shaft 11 is determined by the shape, that is, the profile, of the cam surface C of the cam 14, as in the above-mentioned aspect. By changing it, various rocking patterns can be obtained.

On the other hand, one cam 14 swings only in one direction, and at this time, the other cam 14 guides the cam follower 12 while being in contact with it, so that the swinging operation is easy. This, together with the fact that balaclaran is suppressed, results in a large angular acceleration.

Here, when the change in angular acceleration was examined in the same manner as in the above-described embodiment using the rotational speed of the cam 14 as a parameter, the results shown in FIG. 6 were obtained.

As is clear from this result, a large angular acceleration of I x 105 rad/sec" can be obtained at a relatively low rotational speed of 1800 rpm.

In the above embodiment, one of the idle gears 21 may be omitted, and both rotational drive shafts 13 and cams 14 may rotate in the same direction.

Further, it is also possible to rotate both the cams 14 in the opposite direction to that of the embodiment described above.

As a result, the second cam surface C2 of the other cam 14b presses the cam follower 12b, but since this second cam surface C2 is longer than the first cam surface C1, the unit The amount of movement per time becomes longer, and therefore the torque acting on the swing shaft 11 becomes smaller, making it possible to stabilize the device.

Next, an embodiment related to the third aspect of the present invention will be described based on FIGS. 8 and 9.

Note that since this embodiment has almost the same basic structure as the embodiment of the second aspect described above, only the different points will be described below.

In this embodiment, one of the two cam followers 12 shown in the second embodiment is omitted to provide one cam follower 30, and a pair of cams 14 are brought into contact with both sides of this single cam follower 30. The structure is as follows.

The action and rotational direction of these cams 14 are the same as in the embodiment of the second aspect, but by adopting such a configuration, the dimension in the direction of the swinging surface can be narrowed,
This has the advantage that the device can be made smaller.

Note that the shapes and dimensions of each component shown in each of the above embodiments are merely examples, and can be variously changed based on design requirements and the like.

[Effects of the Invention] As explained above, the first aspect of the rocking generator according to the present invention includes a rocking shaft and a shaft provided on the rocking shaft spaced apart from the rocking center in the rocking radial direction. a cam follower mounted on the cam follower, a rotational drive shaft provided along the swinging wheel, a cam that is integrally attached to the rotational drive shaft and rotated in a plane parallel to the movement plane of the cam follower, and a cam mounted on the swinging shaft. Pressing means or lanyards are arranged in series to keep the cam follower and a cam surface formed on the outer periphery of the cam in constant contact with each other, and the cam surface moves in a direction that separates the cam follower from the rotational drive shaft. a first cam surface that guides the cam follower toward the rotary drive shaft; and a second cam surface that guides the cam follower toward the rotary drive shaft.
and a cam surface of the cam, and the pressing means is a spring, and by moving the cam follower along the shape of the cam, the profile of the cam surface of the cam is changed. By doing so,
The movement speed, that is, the change pattern of the swing angle of the swing axis, the change pattern of the angular velocity, and the change pattern of the angular acceleration can be arbitrarily set. Therefore, an angular acceleration suitable for the purpose of use can be obtained.

According to the second aspect of the present invention, the cam followers are provided on the swing shaft at two positions spaced apart from the center of swing in the swing radius direction and spaced apart in the swing force direction, and a pair of rotary drive shafts provided along the swing shaft on both sides of the cam follower; and a cam having a cam surface that is integrally provided on each of these rotary drive shafts and is brought into sliding contact with each of the cam followers. , a drive mechanism provided between the rotational drive shafts to rotate them synchronously, and a cam surface formed on each of the cams guides each cam follower in a direction away from the rotational drive shaft. and a second cam surface that guides the cam follower in a direction approaching the rotational drive shaft, and both of the cams have the cam follower in contact with the first cam surface of one of the cams. The relative positional relationship is set such that the cam follower is brought into contact with the second cam surface of the other cam when the two rotational drive shafts are rotated in opposite directions. In addition to the effects of the first aspect, reliable rocking can be achieved by applying only a pressing force to the rocking shaft. motion, large angular acceleration can be obtained, and the cam can guide the return of the cam follower after the pressing operation, reducing backlash between them, resulting in smooth rocking. It is possible to realize dynamic movements.

Further, a third aspect of the present invention provides a cam follower provided on the swing shaft at a position spaced apart from the center of swing in the swing radial direction, and a cam follower provided on both sides of the cam follower along the swing shaft. a pair of rotary drive shafts provided at the same time; a cam having a cam surface that is integrally provided on each of these rotary drive shafts and slidably contacts each of the cam followers from both sides in the swinging direction; and a cam between the two rotary drive shafts. and a drive mechanism for rotating these cams synchronously, the cam surface formed on each of the cams having a first cam surface that guides each of the cam followers in a direction to separate them from the rotation drive shaft, and a drive mechanism that rotates the cam followers. and a second cam surface that guides in a direction approaching the drive shaft, and when the cam follower is in contact with the first cam surface of one of the cams,
The relative positional relationship is set so that the cam fuse lower is brought into contact with the second cam surface of the other cam, and the rotational directions of the two rotary drive shafts are opposite directions. , and the rotating direction of both rotary drive shafts is the same direction, and in addition to the effect of the second aspect, the cam is overlapped in the axial direction of the swing shaft to reduce the size of the device. It has excellent effects such as:

[Brief explanation of the drawing]

1 and 2 show an embodiment of the first aspect of the present invention, in which FIG. 1 is a front view showing the main parts, FIG. 2 is a characteristic curve diagram, and FIGS. 3 to 7 are This shows an embodiment of the second aspect of the present invention, in which Fig. 3 is a front view showing the main parts, Fig. 4 is a plan sectional view, Fig. q is an enlarged sectional view of the cam follower part, and Fig. 6 is a characteristic curve diagram, FIG. 7 is a plan cross-sectional view for explaining the connection method with the pond equipment, FIGS. 8 and 9 show the third aspect of the present invention, and FIG. FIG. 9 is a front view showing the main part. 1 (10)... Oscillation generator, 2 (11)...
Swing axis, 3 (12/30)...Cam follower, 4 (
13)...Rotation drive shaft, 5 (14)...Cam, 6
... Pressing means, [5... Drive mechanism, 20... Driven gear, 21... Idle gear, 22... Input shaft, 23... Output shaft, 24... Belt type power transmission mechanism , C... cam surface, C4... first cam surface, C3...
-Second cam surface. Applicant: Mitsuba Electric Manufacturing Co., Ltd. Figure 5

Claims (1)

[Claims] 1) A swing shaft, a cam follower provided on the swing shaft in a radial direction of the swing from the center of swing, and a rotary drive shaft provided along the swing shaft. a cam that is integrally attached to the rotary drive shaft and rotated in a plane parallel to the movement plane of the cam follower; and a cam that is connected to the swing shaft,
the cam follower and a cam surface formed on the outer periphery of the cam are always kept in contact with each other; and a second cam surface that guides the cam follower in a direction approaching the rotational drive shaft 2) A swing generating device characterized in that the pressing means is a spring. Swing generating device according to claim 1 3) Cam followers provided on the swing shaft at two positions spaced apart in the swing radial direction from the swing center and spaced apart in the swing direction, and sandwiching these cam followers. a pair of rotary drive shafts provided along the rocking shaft on both sides, a cam having a cam surface that is integrally provided on each of these rotary drive shafts and is brought into sliding contact with each of the cam followers; a drive mechanism that is provided between the drive shafts and rotates them synchronously; the cam surface formed on each of the cams is a first cam surface that guides each of the cam followers in a direction to separate them from the rotational drive shaft; and a second cam surface that guides the cam follower in a direction approaching the rotational drive shaft, and when the cam follower is in contact with the first cam surface of one of the cams, Oscillation generating device characterized in that the relative positional relationship is set so that the cam follower is brought into contact with the second cam surface of the other cam 4) The rotation directions of both rotational drive shafts are opposite directions. 5) The oscillation generating device according to claim 3, characterized in that the rotation directions of both rotational drive shafts are the same direction. 6) The oscillation generating device according to claim 3, characterized in that the oscillation shaft , a cam follower provided at a position spaced apart in the radial direction of the oscillation from the center of oscillation, a pair of rotary drive shafts provided along the oscillation axis on both sides of the cam follower, and a rotation drive shaft for these. A cam having a cam surface that is integrally provided on each of the shafts and that slides into contact with each of the cam followers from both sides in the swinging direction, and a drive mechanism that is provided between the two rotary drive shafts and rotates them synchronously, The cam surfaces formed on each of the cams include a first cam surface that guides each cam follower in a direction away from the rotational drive shaft, and a second cam surface that guides the cam follower in a direction that approaches the rotational drive shaft. and the two cams are configured such that when the cam follower is in contact with the first cam surface of one cam, the cam follower is in contact with the second cam surface of the other cam. 7) The vibration generating device according to claim 6, characterized in that the rotational directions of both rotational drive shafts are opposite directions. The vibration generating device according to claim 6, wherein the rotational directions of both rotational drive shafts are the same direction.