A differential mechanical speed limiter

Abstract

The present invention provides a differential mechanical speed limiter, which includes a support frame, an outer brake drum and an inner brake drum sequentially installed from the inside out, and the three are coaxially arranged. The ends of the active member and the driven member are both movably connected to the friction blocks, and the friction blocks are located between the outer brake drum and the inner brake drum. After the center of the active member is connected to the center of the driven member, a linkage mechanism is formed. The structure of the linkage mechanism is symmetrical. A driving shaft is provided in the middle of the active member. When the driving shaft rotates along the direction of the force under the action of an external force, the relative position between the active member and the driven member changes, causing the shape of the linkage mechanism to change, and the friction blocks generate a displacement change along the radial direction of the support frame, thereby squeezing the inner brake drum or the outer brake drum to provide braking friction force. The differential mechanical speed limiter described in the present invention solves the problem of realizing product lightweight of the existing speed limiter using rotational centrifugal force, and can be used bidirectionally.

Description

Technical Field

[0001] The present invention belongs to the field of speed limiters, and particularly relates to a differential mechanical speed limiter. Background Art

[0002] Mechanical speed limiters usually utilize rotational motion to generate centrifugal force, causing the braking structure inside the speed limiter to move radially under the action of centrifugal force, and then generating extrusion and friction with the brake drum to achieve deceleration or braking of the moving object. Mechanical speed limiters have the advantages of simple structure and reliable performance, and are widely used in the speed control of precision mechanisms, the speed limit control of aerospace products, and can also be applied to civil fields such as mine mining vehicles and elevators, as well as the deceleration and braking of related devices such as the rapid descent of personnel and goods. The speed limiters of elevators are currently used relatively more. The principle is that when the elevator falls rapidly, the rotating shaft of the speed limiter connected to it rotates rapidly. When the rotational speed reaches a specific value, the heavy block inside the speed limiter moves away from the axis direction under the action of centrifugal force and triggers the alarm device to achieve the braking function.

[0003] The current mechanical speed limiters usually use rotational centrifugal force to achieve speed limit and braking. Since the magnitude of rotational centrifugal force is directly related to the mass of the rotating object, a relatively large mass of heavy block usually needs to be equipped inside to generate sufficient frictional force to achieve specific speed limit performance. Therefore, the mass of the existing speed limiters is usually relatively large, making it difficult to meet the requirements of usage scenarios with strict weight limitations, and it is difficult to achieve product lightweight. In addition, most of the current mechanical speed limiters adopt rotational structures and are not completely symmetrical. Therefore, there are differences in the speed limit effects when the rotating shaft rotates in different directions during operation, making it difficult to meet the requirements of bidirectional use. The existing mechanical speed limiters mainly utilize the principle of generating centrifugal force by rotational motion. According to this principle, it can be known that such speed limiters can only control the change of speed, with relatively low sensitivity, and cannot control acceleration. In application scenarios where acceleration needs to be controlled, the traditional mechanical speed limiters are difficult to meet the usage requirements. Summary of the Invention

[0004] In view of this, the present invention aims to propose a differential mechanical speed limiter to solve the problems that the current speed limiters cannot be used bidirectionally and have a relatively large mass.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] A differential mechanical speed limiter includes an active member, a driven member, friction blocks, a support frame, and an outer brake drum and an inner brake drum that are sequentially installed from the inside out. The support frame, the outer brake drum, and the inner brake drum are coaxially arranged. The ends of the active member and the driven member are both movably connected to the friction blocks, and the friction blocks are located between the outer brake drum and the inner brake drum. The centers of the active member and the driven member are fixedly connected to form a linkage mechanism. The linkage mechanism is a single-degree-of-freedom linkage mechanism with a symmetric structure. A driving shaft is provided in the middle of the active member. When the driving shaft rotates along the direction of the force under the action of an external force, the relative positions between the active member and the driven member change, causing the shape of the linkage mechanism to change, and the friction blocks generate a displacement change along the radial direction of the support frame, thereby squeezing the inner brake drum or the outer brake drum to provide braking friction force.

[0007] Further, the active member includes an active part, a plurality of friction rods, and a driving shaft. The active part includes a plurality of identical active rods. The plurality of active rods are circumferentially distributed and fixedly connected at the axis to form a radial shape. The driving shaft is fixedly installed on one side of the axis. The end of each active rod is movably connected to the first end of a friction rod, and the second end of the friction rod is movably connected to a friction block.

[0008] Further, the friction blocks are of a cylindrical structure.

[0009] Further, the active part includes 3 active rods, and the 3 active rods are fixedly connected to form a Y-shaped structure. The driving shaft is fixedly installed on one side of the intersection of the three active rods, and the included angle between two adjacent active rods is 120°.

[0010] Further, the active part includes 8 active rods, and the 8 active rods are fixedly connected to form a cross-shaped structure, and the included angle between two adjacent active rods is 45°.

[0011] Further, the driven member includes a driven part, a plurality of linkage rods, and a driven shaft. The driven part includes a plurality of identical driven rods. The number of driven rods is the same as the number of active rods. The plurality of driven rods are circumferentially distributed and fixedly connected at the axis to form a radial shape. A through hole is formed at the axis, and the driven shaft is fixedly installed on the outer circle of the through hole. The driven shaft is a hollow ring, and the driven shaft and the driving shaft are connected by a rotating pair; the end of each driven rod is movably connected to the first end of a linkage rod, and the second end of the linkage rod and the second end of the friction rod are movably connected to the friction block.

[0012] Further, the driven part includes 3 driven rods, and the 3 driven rods are fixedly connected to form a Y-shaped structure. A through hole is formed at the intersection of the 3 driven rods, and the driven shaft is fixedly installed on the outer circle of the through hole. The included angle between two adjacent driven rods is 120°.

[0013] Further, the driven part includes eight driven rods, and the eight driven rods are fixedly connected to form a cross structure, and the included angle between two adjacent driven rods is 45°.

[0014] Compared with the prior art, the differential mechanical speed limiter of the present invention has the following advantages:

[0015] (1) The differential mechanical speed limiter of the present invention solves the problem of realizing product lightweight of the existing speed limiter using rotational centrifugal force, making the external volume of the speed limiter smaller, the mass lighter, and it can be used bidirectionally, with stronger adaptability to the working environment.

[0016] (2) The differential mechanical speed limiter of the present invention adopts a single-degree-of-freedom link mechanism, greatly reducing the external dimensions of the speed limiter and improving the flexibility and reliability of the speed limiter. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation to the present invention. In the drawings:

[0018] Figure 1 is a schematic structural diagram of the differential mechanical speed limiter according to an embodiment of the present invention;

[0019] Figure 2 is a schematic side view diagram of the differential mechanical speed limiter according to an embodiment of the present invention;

[0020] Figure 3 is a schematic diagram of the driving part according to an embodiment of the present invention;

[0021] Figure 4 is a schematic diagram of the driven part according to an embodiment of the present invention;

[0022] Figure 5 is a schematic diagram of the link mechanism according to an embodiment of the present invention;

[0023] Figure 6 is a schematic diagram of the support frame according to an embodiment of the present invention;

[0024] Figure 7 is a schematic diagram of the working state of the inner brake drum of the differential mechanical speed limiter according to an embodiment of the present invention;

[0025] Figure 8 is a schematic diagram of the working state of the outer brake drum of the differential mechanical speed limiter according to an embodiment of the present invention.

[0026] Description of the reference numerals:

[0027] 1 - Support frame; 2 - Outer brake drum; 3 - Driving part; 31 - Driving rod; 4 - Driven part; 41 - Driven rod; 5 - Linking rod; 6 - Friction rod; 7 - Friction block; 8 - Inner brake drum; 9 - Driving shaft; 10 - Driven shaft; 11 - Cotter screw. Detailed implementation manners

[0028] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments may be combined with each other.

[0029] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and 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 operated in a specific orientation, and thus should not be construed as a limitation of the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, the meaning of "a plurality" is two or more.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", "coupled" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0031] The present invention will be described in detail below with reference to the drawings and in combination with the embodiments.

[0032] A differential mechanical speed limiter, as Figures 1 to 8As shown in the figure, it includes a support frame 1, an outer brake drum 2, a driving part 3, a driven part 4, a linkage rod 5, a friction rod 6, a friction block 7, an inner brake drum 8, a driving shaft 9, a driven shaft 10, a pin screw 11, a driving member, and a driven member. The support frame 1 fixedly installs the outer brake drum 2 and the inner brake drum 8 in sequence from the inside to the outside, and the support frame 1, the outer brake drum 2, and the inner brake drum 8 are coaxially arranged. The ends of the driving member and the driven member are both movably connected to the friction block 7. The friction block 7 is located between the outer brake drum 2 and the inner brake drum 8. After the centers of the driving member and the driven member are fixedly connected, a linkage mechanism is formed. The linkage mechanism is a symmetric structure and a single-degree-of-freedom linkage mechanism. The speed limiter has good symmetry inside and does not adopt the form of a weight. It not only realizes the function of two-way speed limit of the product, but also simplifies the internal structure of the speed limiter and solves the problem of weight reduction of the speed limiter. A driving shaft 9 is provided in the middle of the driving member. The driving shaft 9 is connected to the support frame 1 in a limited and movable manner and extends out of the support frame 1. When the driving shaft 9 rotates under the action of an external force along the direction of the force, the relative position between the driving member and the driven member changes, causing the shape of the linkage mechanism to change, and the friction block 7 generates a displacement change in the radial direction of the speed limiter rotating shaft (support frame 1), so as to squeeze the inner brake drum 8 or the outer brake drum 2 to provide braking friction force. The differential mechanical speed limiter of the present invention solves the problem of weight reduction of the existing speed limiter using rotational centrifugal force, makes the external volume of the speed limiter smaller and the mass lighter, and can be used bidirectionally, with stronger adaptability to the working environment.

[0033] The driving member includes a driving part 3, a friction rod 6, and a driving shaft 9. The driving part 3 is a symmetric structure. The driving part 3 includes a number of identical driving rods 31. The driving rods 31 are circumferentially distributed and fixedly connected at the axis to form a radial shape. One side of the axis fixedly installs the driving shaft 9. The end of each driving rod 31 is movably connected to the first end of the friction rod 6, and the second end of the friction rod 6 is movably connected to the friction block 7.

[0034] The friction block 7 is a cylindrical structure, which is convenient for tangential friction with the outer edge of the inner brake drum 8 and the outer edge of the outer brake drum 2 to generate braking.

[0035] Specifically, one end of each driving rod 31 is fixedly connected to one end of other driving rods 31, and the other end is rotatably connected to the first end of the friction rod 6 and the center of the friction block 7 through a pin screw 11.

[0036] Preferably, the driving part 3 is an integral structure, and the driving part 3 and the driving shaft 9 are connected by a tight fit of the shaft hole.

[0037] In one embodiment, as Figure 3As shown, the driving part 3 includes three driving rods 31. The three driving rods 31 are fixedly connected to form a Y-shaped structure. One side of the junction of the three driving rods 31 is fixedly installed with a driving shaft 9, and the included angle between two adjacent driving rods 31 is 120°. In another embodiment, the driving part 3 includes eight driving rods 31. The eight driving rods 31 are fixedly connected to form a cross-shaped structure, and the included angle between two adjacent driving rods 31 is 45°.

[0038] The driven member includes a driven part 4, a linkage rod 5 and a driven shaft 10. The driven part 4 includes a number of identical driven rods 41. The number of driven rods 41 is the same as that of the driving rods 31. The number of driven rods 41 is circumferentially evenly distributed and fixedly connected at the axis to form a radial shape. A through hole is formed at the axis. The outer ring of the through hole is fixedly installed with the driven shaft 10. The driven shaft 10 is a hollow ring. The inner diameters of the through hole and the driven shaft 10 are the same. The driven shaft 10 and the driving shaft 9 are connected by a rotating pair; the end of each driven rod 41 is movably connected to the first end of the linkage rod 5, and the second end of the linkage rod 5, the second end of the friction rod 6 and the friction block 7 are movably connected to each other.

[0039] The driven part 4 is a symmetric structure. The shape of the driven part 4 corresponds to the shape of the driving part 3. Preferably, the driven part 4 is an integral structure, and the driven part 4 and the driven shaft 10 are an integral structure.

[0040] In one embodiment, as Figure 4 shown, the driven part 4 includes three driven rods 41. The three driven rods 41 are fixedly connected to form a Y-shaped structure. A through hole is formed at the junction of the three driven rods 41. The outer ring of the through hole is fixedly installed with the driven shaft 10, and the included angle between two adjacent driven rods 41 is 120°. In another embodiment, the driven part 4 includes eight driven rods 41. The eight driven rods 41 are fixedly connected to form a cross-shaped structure, and the included angle between two adjacent driven rods 41 is 45°.

[0041] As Figure 6 shown, the support frame 1 is a hollow cylindrical structure with one end open. An inner brake drum 8 is fixedly installed (welded or integral) on the inner wall of the support frame 1. The inner brake drum 8 is a ring structure. An installation hole is provided at the center of the support frame 1. The outer brake drum 2 is fixedly installed (screwed or welded) on the support frame 1, and the three are coaxially arranged.

[0042] The outer diameter of the driving shaft 9 is smaller than the inner diameter of the installation hole, so that when the driving shaft 9 passes through the installation hole, it can rotate in the installation hole under the action of an external force. This structure enables the driving shaft 9 to be rotatably connected to the support frame 1, and at the same time, the installation hole plays a limiting role on the driving shaft 9.

[0043] The outer brake drum 2 is a hollow ring structure.

[0044] In the link mechanism herein, all movable connections are rotational connections connected by pin screws 11.

[0045] As Figure 1 , Figure 2 , Figure 7 , Figure 8 shown, in one embodiment (the linkage mechanism includes 3 linkage rods 5, 3 friction rods 6, 3 friction blocks 7, 3 driving rods 31 and 3 driven rods 41), the connection process between the linkage mechanism and the support frame 1 is as follows:

[0046] The driving shaft 9 is connected to the driving part 3 by a tight fit through a shaft hole. The driving shaft 9 sequentially passes through the through holes of the driven shaft 10 and the driven part 4 and the mounting hole of the support frame 1. The driving shaft 9 and the driven shaft 10 are rotationally connected, and the driving shaft 9 and the mounting hole are limitedly connected. Each driving rod 31 of the driving part 3 is rotationally connected to the first end of a friction rod 6, and each driven rod 41 of the driven part 4 is rotationally connected to the first end of a linkage rod 5. The second end of a linkage rod 5, the second end of a friction rod 6 and the center of a friction block 7 are rotationally connected. During the rotation process, the speed difference generated between the two components of the driving component and the driven component, as well as the inertial force and damping generated during the movement of the object, use the inertial force as the deformation force generated by the linkage mechanism inside the speed limiter and further convert it into frictional resistance to achieve the control of the rotational speed. In order to reduce the external dimensions of the speed limiter and improve the flexibility and reliability of the speed limiter, a single-degree-of-freedom linkage mechanism is adopted inside the speed limiter.

[0047] The working principle of a differential mechanical speed limiter is as follows:

[0048] When the speed limiter works, the driving component rotates along the set direction. The change in the relative position between the driving and driven components causes the shape of the linkage mechanism to change, causing the friction block 7 installed at the connection between the linkage rod 5 and the friction rod 6 of the linkage mechanism to generate a displacement change in the radial direction of the speed limiter rotating shaft, thereby squeezing the inner brake drum 8 or the outer brake drum 2 to provide braking frictional force. The inside of the speed limiter has good symmetry and does not adopt the form of heavy blocks, which not only realizes the two-way speed limiting function of the product, but also simplifies the internal structure of the speed limiter and solves the problem of weight reduction of the speed limiter.

[0049] When the speed limiter is in a non-operating state, the active component and the driven component maintain a specific relative position, the linkage mechanism maintains a specific shape, and the friction block 7 at the end of the linkage mechanism is also separated from the friction drum (outer brake drum 2 and inner brake drum 8). When the driving shaft 9 rotates, the driving shaft 9 drives the active component to rotate, and at the same time the active component drives the driven component to rotate. The driven component is subject to its own inertia force and the friction force of the system. When the rotational speed of the driving shaft 9 gradually increases, a certain range of relative movement occurs between the driven component and the active component, thereby driving the linkage mechanism to change its shape, causing the friction block 7 installed at the connection of the linkage rod 5 and the friction rod 6 of the linkage mechanism to move radially along the axis of the speed limiter. When the rotational speed of the shaft reaches the set range, the friction block 7 will contact the friction drum (outer brake drum 2 or inner brake drum 8) and generate a certain contact normal pressure. The contact normal pressure generates a frictional force, that is, a rotational resistance moment, on the friction contact surface, hindering the rotation of the shaft, thereby realizing the speed limiting function.

[0050] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A differential mechanical speed limiter, characterized in that: It includes an active member, a driven member, friction blocks, a support frame, and an outer brake drum and an inner brake drum installed sequentially from the inside out. The support frame, the outer brake drum, and the inner brake drum are coaxially arranged. The ends of the active member and the driven member are both movably connected to the friction blocks. The friction blocks are located between the outer brake drum and the inner brake drum. After the centers of the active member and the driven member are connected, a linkage mechanism is formed. The linkage mechanism is a single-degree-of-freedom linkage mechanism with symmetrical structure. A driving shaft is provided in the middle of the active member. When the driving shaft rotates along the direction of the force under the action of an external force, the relative position between the active member and the driven member changes, causing the shape of the linkage mechanism to change, and the friction blocks generate a displacement change along the radial direction of the support frame, thereby squeezing the inner brake drum or the outer brake drum to provide braking friction force; The active member includes an active part, several friction rods, and a driving shaft. The active part includes several identical active rods. The several active rods are circumferentially distributed and fixedly connected at the axis to form a radial shape. One side of the axis is fixedly installed with the driving shaft. The end of each active rod is movably connected to the first end of a friction rod, and the second end of the friction rod is movably connected to a friction block; The driven member includes a driven part, several linkage rods, and a driven shaft. The driven part includes several identical driven rods. The number of driven rods is the same as the number of active rods. The several driven rods are circumferentially distributed and fixedly connected at the axis to form a radial shape. A through hole is formed at the axis. The outer ring of the through hole is fixedly installed with the driven shaft. The driven shaft is a hollow ring, and the driven shaft and the driving shaft are connected by a revolute pair; the end of each driven rod is movably connected to the first end of a linkage rod, and the second end of the linkage rod and the second end of the friction rod are movably connected to the friction block.

2. The differential mechanical speed limiter according to claim 1, characterized in that: The friction block is of a cylindrical structure.

3. The differential mechanical speed limiter according to claim 1, characterized in that: The active part includes 3 active rods, and the 3 active rods are fixedly connected to form a Y-shaped structure. One side of the intersection of the three active rods is fixedly installed with the driving shaft, and the included angle between two adjacent active rods is 120°.

4. The differential mechanical speed limiter according to claim 1, characterized in that: The active part includes 8 active rods, and the 8 active rods are fixedly connected to form a cross-shaped structure, and the included angle between two adjacent active rods is 45°.

5. The differential mechanical speed limiter according to claim 1, characterized in that: The driven part includes 3 driven rods, and the 3 driven rods are fixedly connected to form a Y-shaped structure. A through hole is formed at the intersection of the 3 driven rods. The outer ring of the through hole is fixedly installed with the driven shaft, and the included angle between two adjacent driven rods is 120°.

6. The differential mechanical speed limiter according to claim 1, characterized in that: The driven part includes 8 driven rods, and the 8 driven rods are fixedly connected to form a cross-shaped structure, and the included angle between two adjacent driven rods is 45°.

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