A demonstration device capable of adjusting the ring oscillation state

Abstract

The present invention belongs to the field of motion state demonstration devices, and relates to a demonstration device with adjustable ring vibration state, comprising a rigid ring, a fixed frame fixed inside the rigid ring and passing through the center of the rigid ring, a rotating shaft is provided at a position matching the center of the rigid ring, a driver for driving the rotating shaft is connected to the rotating shaft, a swing rod for changing the center of gravity is provided on the rotating shaft, and the swing rod is driven to rotate by the driver to change the center of gravity of the device. The present invention proposes a ring vibration state demonstration device with small size and light weight, long ring vibration maintenance time, and can effectively adjust the angle between the ring surface and the ground during ring vibration movement and is easy to observe.

Description

Technical Field

[0001] The invention belongs to the field of motion state demonstration devices, and relates to a demonstration device capable of adjusting the ring oscillation state. Background Art

[0002] Ring oscillation motion refers to a state where a rigid ring, under the action of an external force, rotates around a central axis perpendicular to the ring surface and passing through the center of the ring. At the same time, the central axis also rotates around an axis perpendicular to the ground, and the projection point of the axis on the ground is within the curve of the projection of the rigid ring on the ground. Ring oscillation motion is a common physical phenomenon and is often used as a focus of teaching and discussion when explaining the motion state of a falling iron ring.

[0003] Since the ring vibration state lasts for a short time when the iron ring falls naturally, it is not convenient to observe and demonstrate. At present, the main demonstration method of the ring vibration state is to rely on people to throw the iron ring for demonstration, which does not have the ability to maintain the ring vibration state for a long time, which is not conducive to the observation of this state of motion. At the same time, this method has problems such as poor stability, low demonstration success rate, and short observable time. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a demonstration device with adjustable ring vibration state, which can be driven by itself, maintain the ring vibration for a long time, and can adjust the angle between the ring surface and the ground during the ring vibration movement to facilitate observation.

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] A demonstration device with adjustable ring vibration state includes a rigid ring, a fixing frame fixed inside the rigid ring and passing through the center of the rigid ring, a rotating shaft is provided at a position matching the center of the rigid ring, a driver for driving the rotating shaft to rotate is connected to the rotating shaft, a pendulum rod for changing the center of gravity is provided on the rotating shaft, and the pendulum rod is driven to rotate by the driver to change the center of gravity of the device.

[0007] Optionally, a detachable counterweight block is also provided on the swing rod.

[0008] Optionally, the fixed position of the counterweight on the rocker arm is adjustable.

[0009] Optionally, there are multiple counterweight blocks.

[0010] Optionally, the fixing frame is in a straight line shape, a cross shape or a herringbone shape.

[0011] Optionally, the swing rod is in a straight line shape or a circular ring shape.

[0012] Optionally, the rotating shaft is fixed to the fixing frame via a flange.

[0013] Optionally, a plane defining an annular surface of the rigid ring is defined as a first plane, and a plane passing through the center of the rigid ring and parallel to the first plane is defined as a second plane; and the fixing frame is arranged in the second plane.

[0014] Optionally, the rotation plane of the rocker arm is parallel to the first plane.

[0015] Optionally, the swing rod is in the shape of a ring, and a support rod for mounting a counterweight is provided inside the swing rod. The support rods are arranged in a herringbone shape, and the cross portion thereof is located at the center of the swing rod.

[0016] The beneficial effects of the present invention are:

[0017] The present invention proposes a demonstration device design scheme that is small in size and light in weight, maintains ring vibration for a long time, can effectively adjust the angle between the ring surface and the ground during ring vibration movement, and is easy to observe. The main technical problems to be solved are the stability of the ring vibration movement state, the adjustment of the angle between the ring surface and the ground during ring vibration, etc.

[0018] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0020] Figure 1 Schematic diagram of ring vibration motion;

[0021] Figure 2 This is a schematic diagram of the structure of Embodiment 1 of the present invention;

[0022] Figure 3 is a schematic diagram of the angle α;

[0023] Figure 4 It is a schematic diagram of the force of the device;

[0024] Figure 5 It is a schematic diagram of the regulation principle;

[0025] Figure 6 This is a schematic diagram of the motion state of Example 1;

[0026] Figure 7 This is a schematic diagram of the motion state of Example 2. DETAILED DESCRIPTION

[0027] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0028] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0029] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0030] See also Figure 1-Figure 7 The component numbers in the accompanying drawings represent: fixed frame 1, driver 2, rigid ring 3, flange 4, counterweight 5, and rocker arm 6 respectively.

[0031] The present invention discloses a demonstration device with adjustable ring vibration state, which is mainly composed of a rigid ring 3, a fixing frame 1, a flange 4, a driver 2, a swing rod 6 and a counterweight 5. The fixing frame 1 can be in the shape of a straight line, a herringbone, or a cross. The fixing frame 1 is installed on the inner side of the rigid ring 3 and passes through the center of the ring, and is used to fix the flange 4; one end of the flange 4 is installed on the fixing frame 1 at the center of the ring, and the other end is connected to the shaft of the driver 2; the driver 2 is installed at one end of the swing rod 6, and the driver 2 is provided with driving force by a motor or other power device to drive the swing rod 6 to rotate; the swing rod 6 can be in the shape of a straight line, a herringbone, or a ring. Under the action of the driver 2, the swing rod 6 can rotate around the central axis perpendicular to the ring surface and passing through the center of the ring, so as to change the center of gravity of the device; the counterweight 5 is fixed on the swing rod 6, and the center of gravity of the annular device is changed by the rotation of the swing rod 6.

[0032] The ring surface of the device is placed vertically on the ground. When the driver 2 is not working, due to the influence of gravity, the line connecting the center of the ring and the center of mass of the counterweight 5 is vertical to the ground. Figure 2 As shown, at this time, the swing rod 6 and the ground form a 90-degree angle.

[0033] Process analysis of the device from startup to stabilization:

[0034] When starting, tilt the device by hand and give an initial velocity that causes the device ring surface to twist around the line connecting the highest point and the lowest point of the ring surface off the ground. At this time, the pendulum 6 will move to a suitable position, such as Figure 3 As shown in the figure, it always maintains a suitable angle α with the line connecting the center of the ring and the point where the ring touches the ground. Since the counterweight 5 is fixed on the swing rod 6, the center of gravity of the entire device changes significantly. At this time, the stress condition of the device is as follows: Figure 4 As shown, the center of gravity of the device is near the counterweight 5, and it is subject to gravity G, ground support force Fb, and friction force Fa. Since gravity G and support force Fb are equal in magnitude and opposite in direction and not collinear, the device will rotate at this time, causing the device to rotate and move forward. The rotation direction is as follows Figure 4 As shown in the figure V, the device is tilted at this time, and the friction force provides the centripetal force, causing the device to enter the ring vibration state. Due to friction loss, the potential energy of the device is reduced, the angle between the ring surface and the ground will decrease, and the time for the particles on the ring to touch the ground twice in a row will become shorter. At this time, the driver 2 drives the pendulum 6 to increase the angle α appropriately to compensate for the energy loss. Within a certain angle range, even if there is a slight external disturbance, the driver 2 can dynamically adjust the angle α to increase the potential energy to compensate for the energy loss, so that the angle between the ring surface and the ground can remain stable.

[0035] Analysis of the principle of ring oscillation state adjustment:

[0036] like Figure 5 As shown in the figure, the Z axis is the axis perpendicular to the ground when the device is ring-vibrating, the S axis is the central axis perpendicular to the ring surface and passing through the center of the ring, the solid line circle in the figure is the device, the dotted line circle is the trajectory of the device's rotation axis when it passes through the plane, and the angle θ is the angle between the central axis S and the axis Z perpendicular to the ground. Assume that the angle between the central axis S of the device and the Z axis at time t is θ, the angular velocity is ω, the moment of inertia is I, and the projection of the angular momentum on the Z axis is Lcosθ; at time t+dt, due to the action of the gravity torque M, the device will tilt downward, so that the angle between the S axis and the Z axis becomes θ+dθ, and the projection of the angular momentum on the Z axis becomes Lcos(θ+dθ), then the increment of the angular momentum in the Z axis direction is:

[0037] dL z =Lcos(θ+dθ)-Lcosθ=-Lsinθdθ=-Iωsinθdθ

[0038] However, M has no component in the Z-axis direction, so the angular momentum of the device must be conserved in the Z-axis direction, which means that the device will definitely obtain an angular momentum Iωsinθdθ along the positive direction of the Z-axis, causing the central axis S of the device to rotate counterclockwise along the Z-axis, generating ring vibration.

[0039] Since the angular velocity ω of the device around the S axis is much greater than its angular velocity around the Z axis, the total angular momentum of the device is approximately equal to the sum of the angular momentum of the pendulum 6 and the angular momentum of the rotation around the S axis, and can therefore be represented by L. Figure 6 As shown in the figure, when the pendulum 6 of the device rotates through a small angle dφ, the increment of the angular momentum of the device (assuming that θ remains unchanged) dL=Lsin θdφ=Iωsinθdφ. Noting the differential form of the angular momentum theorem dL=M2dt (M2 is the torque of the resultant external force), the angular velocity of the central axis S rotating around the Z axis can be obtained, that is, the angular velocity of the ring oscillation of the device Angle between the torus and the ground This formula shows that within 0-90 degrees, the angle θ between the torus and the ground is proportional to the torque M2 of the resultant external force on the device. This device uses this principle. Within a certain range, the angle α is proportional to the torque of the resultant external force. The torque of the resultant external force on the device is changed by adjusting the angle α by the driver 2, thereby changing the ring vibration state of the device. Within a certain range (such as within 30-80 degrees), the angle between the torus and the ground can be reduced by appropriately reducing the angle α; within a certain range (such as within 30-80 degrees), the angle between the torus and the ground can be increased by appropriately increasing the angle α.

[0040] Example 1

[0041] Reference Figure 6 The device of this example is composed of a rigid ring 3, a straight-shaped fixing frame 1, a flange 4, a driver 2, a straight-shaped swing rod 6, and two counterweights 5. The driver 2 is driven by a motor, and the rigid ring 3, the fixing frame 1 and the swing rod 6 are all made of aluminum alloy.

[0042] When the device is started, the device is tilted by hand and an initial velocity is given to make the device ring surface twist around the line connecting the highest point and the lowest point of the ring surface. At this time, the pendulum 6 will move to a suitable position, such as Figure 6 As shown, when the angle α is lower than the set lower threshold, the driver 2 is started, and the straight-line pendulum 6 rotates, so that the device enters the ring vibration state and keeps the angle between the ring surface and the ground unchanged.

[0043] When the device is in the ring oscillation state, within a certain range, the angle between the ring surface and the ground can be reduced by appropriately reducing the angle α through the driver 2; within a certain range, the angle between the ring surface and the ground can be increased by appropriately increasing the angle α through the driver 2.

[0044] Example 2

[0045] Reference Figure 7 The device of this example is composed of a rigid ring 3, a straight-shaped fixing frame 1, a flange 4, a driver 2, an annular swing rod 6 and two counterweights 5. The driver 2 is driven by a motor, and the rigid ring 3, the fixing frame 1 and the swing rod 6 are all made of aluminum alloy.

[0046] When the device is started, the device is tilted by hand and an initial velocity is given to make the device ring surface twist around the line connecting the highest point and the lowest point of the ring surface. At this time, the annular pendulum 6 will move to a suitable position, such as Figure 4 As shown, when the angle α is lower than the set lower threshold, the driver 2 is started and the annular pendulum 6 rotates, so that the device enters the ring vibration state and keeps the angle between the ring surface and the ground unchanged.

[0047] When the device is in the ring oscillation state, within a certain range, the angle between the ring surface and the ground can be reduced by appropriately reducing the angle α through the driver 2; within a certain range, the angle between the ring surface and the ground can be increased by appropriately increasing the angle α through the driver 2.

[0048] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A demonstration device with adjustable ring oscillation state, characterized in that: The invention comprises a rigid ring, a fixing frame fixedly arranged inside the rigid ring and passing through the center of the rigid ring, a rotating shaft is arranged at a position matching the center of the rigid ring, a driver for driving the rotating shaft is connected to the rotating shaft, a swing rod for changing the center of gravity is arranged on the rotating shaft, and the swing rod is driven to rotate by the driver to change the center of gravity of the device; a plane of an annular surface of the rigid ring is defined as a first plane, and a plane passing through the center of the rigid ring and parallel to the first plane is defined as a second plane; the fixing frame is arranged in the second plane; the rotating surface of the swing rod is parallel to the first plane; the device When starting, tilt the device by hand and give an initial velocity that causes the device's ring surface to twist around the line connecting the highest point and the lowest point of the ring surface. At this time, the pendulum will move to a suitable position and always maintain a suitable angle α with the line connecting the center of the ring and the ring contact point. When the angle α is lower than the set lower threshold, the driver starts, and the straight-line pendulum rotates, causing the device to enter the ring vibration state and keep the angle between the ring surface and the ground unchanged; when the device is in the ring vibration state, the angle between the ring surface and the ground can be reduced by reducing the angle α through the driver; the angle between the ring surface and the ground can be increased by increasing the angle α through the driver.

2. The demonstration device with adjustable ring oscillation state as claimed in claim 1, characterized in that: The swing rod is also provided with a detachable counterweight.

3. The demonstration device with adjustable ring oscillation state as claimed in claim 2, characterized in that: The fixing position of the counterweight on the swing rod is adjustable.

4. The demonstration device with adjustable ring oscillation state as claimed in claim 2, characterized in that: There are multiple counterweight blocks.

5. The demonstration device with adjustable ring oscillation state as claimed in claim 1, characterized in that: The fixing frame is in a straight line shape, a cross shape or a herringbone shape.

6. The demonstration device with adjustable ring oscillation state as claimed in claim 1, characterized in that: The rotating shaft is fixed on the fixing frame via a flange.

7. The demonstration device with adjustable ring oscillation state as claimed in claim 6, characterized in that: The swing rod is in the shape of a circular ring, and a support rod for installing a counterweight is arranged inside the swing rod. The support rods are arranged in a herringbone shape, and the cross portion thereof is located at the center of the swing rod.

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