WO2006039858A1 - A ratchet overrunning clutch - Google Patents

Abstract

A ratchet overrunning clutch comprising a ratchet wheel (1) with a number of ratchet teeth (7) and a pawl disk member (2) with a number of pawl (3) and the reset means thereof is disclosed. The pawl disk member (2) and the ratchet wheel (1) are supported by a bearing (15) so that the pawl disk member (2) and the ratchet wheel (1) can rotate coaxially. The pawl (3) is an integral structure. The pawl (3) includes a head end (9), a shaft portion (10) and a tail end (11). The head end (9) includes a contacting end (8) having a contacting surface (13). The shaft portion (10) is rotationally supported on the disk member (2) by a shaft pin (4). The tail end (11) is opposing to the reset means so as to be applied the acting force of the reset means. The pawl (3) is T - shaped cross section. The width of the contacting end (8) is larger than the width of the shaft portion (10) and the tail end (11) respectively. When the clutch is used in the case of frequently engagement, the pawl (3) can be resetted quickly to improve engagement accuracy. When the clutch is used in the case of a long - time overrun, the pawl (3) can be disengaged with the ratchet teeth (7) to avoid worn.

Description

技术领域

Technical field

 BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a ratchet overrunning clutch. The novel pawl structure and its resetting device can make the overrunning clutch reliably used for a long-term overloaded working state and a long-time overrun working state. Background technique

 Chinese patent CN 91208227. 5 discloses an inertial centrifugal ratchet in which a magnetic ring is disposed under the ratchet. When the gear rotates, the pawl expands radially outwardly by the centrifugal force to engage the ratchet teeth on the ratchet. According to the technical solution disclosed in the patent, since the power acting on the pawl to swing radially outward to mesh with the ratchet on the ratchet is centrifugal force, when the pawl is inflexible, the ratchet Can't work reliably.

US Patent No. 5,205,386 discloses a ratchet overrunning clutch with a pawl retaining device in which a magnet is provided on the radially outer side of the pawl engaging end, and the pawl is in centrifugal force when the rotational speed of the output shaft exceeds a desired value. Under the action of the radial outward swing, once it is in contact with the corresponding magnet, it will be held by the magnet. The clutch is still driven by a spring force to drive the pawl to oscillate with the ratchet on the ratchet. This clutch can only be used for long-term overrunning. When the heavy load frequently exceeds, the spring will be repeatedly and frequently loaded, and the spring will be fatigue fractured, resulting in the entire clutch not working properly. In addition, the pawl relies on the centrifugal force, the elastic force and the magnetic force to engage or disengage the ratchet. The instability of the clutch speed, the spring action of the spring and the magnetic attenuation of the magnet all affect the long-term normal operation of the clutch. Chinese patent ZL00254031. 2 Gong Hui has a ratchet overrunning clutch with a pawl that relies on magnetic reset. This type of clutch is suitable for frequent meshing operation. When used for a long time beyond the working state, the pawl and the ratchet need to be in frequent contact, which is easy to wear and damage the component. The patent defines that the pawl disk is an inner ring and the ratchet wheel is an outer ring. In some use cases, the overrunning clutch must adopt a structure in which the pawl disk is an outer ring.

Summary of the invention

 SUMMARY OF THE INVENTION An object of the present invention is to overcome the deficiencies of the prior art overrunning clutch technology and to provide a ratchet overrunning clutch using a novel pawl structure and a resetting device thereof, thereby improving the performance of the overrunning clutch. When the clutch is used for frequent engagement, the new pawl structure can be quickly reset to improve the engagement accuracy with the ratchet; when the clutch is in the overrun state for a long time, the pawl and ratchet can be completely disengaged to avoid wear. This is a ratchet overrunning clutch that is more reliable, more versatile and has a longer service life.

 The object of the present invention is achieved by the following scheme.

A ratchet overrunning clutch according to the present invention includes a ratchet wheel provided with a ratchet, a pawl disk provided with a pawl and a resetting device thereof, and bearing support between the two to ensure that the ratchet and the pawl disk can rotate coaxially The pawl structure is a unitary structure divided into three parts: a head portion, a shaft portion and a tail portion. The pawl head portion includes a contact end having a contact surface, and the pawl shaft portion is rotatably mounted on the pawl plate by a shaft pin. The pawl tail portion is disposed corresponding to the resetting device to receive the force of the resetting device. The pawl structure has a "T" shape in plan view, and the width of the head contact end of the pawl structure is greater than the width of the shaft portion and the tail portion.

The ratchet overrunning clutch is characterized in that the head portion, the shaft portion and the tail portion of the pawl structure are in a "T" shape, and the head portion includes a contact end having a contact surface, the width of which is larger than the pawl axis. The width of the part and the tail. This structure optimizes the force state of the pawl so that the compressive stress on the head contact surface of the pawl and the shear stress of the pin are at the same level. The wide portion of the first contact end can also serve as a limit function for the rotation of the pawl structure, so that the tail portion of the pawl structure does not come into contact with the ratchet when the pawl and the ratchet are disengaged.

 With the ratchet overrunning clutch of the "T"-shaped pawl structure, the force of the pawl and its axle pin is more reasonable, and the clutch can transmit more torque than other types of overrunning clutches of the same structural size; The number of claws and the number of ratchets are prime numbers. When engaged, each pawl has a pawl that engages with the ratchet to extend the service life of the clutch. By changing the number and structure of the pawl and ratchet, the clutch can be effectively changed. The engagement accuracy (return angle) or the transmission torque; the pawl structure adjusts the interaction between the restoring force and the centrifugal force to achieve frequent engagement with the ratchet or long-term disengagement, making the clutch operation more stable and reliable. . DRAWINGS

FIG 1 is a ratchet pawl overrunning clutch disc of the present invention as the outer clutch, the inner ring is a side view of the ratchet; ¹

 Figure 2 is a cross-sectional view of the pawl disk of Figure 1 as a clutch outer ring;

 Figure 3 is a side view of the pawl disk as a bad inside the clutch and the outer ring of the ratchet;

 Figure 4 is a cross-sectional view of the pawl disk of Figure 3 as a clutch inner ring;

 Figure 5 is a side elevational view of the pawl structure of Figure 1;

 Figure 6 is a plan view of the pawl structure shown in Figure 5;

 Figure 7 is a diagram showing the working state of the pawl completely out of the ratchet.

— O — detailed description

 According to the figure, the present invention is a ratchet overrunning clutch comprising a ratchet 1 provided with a plurality of ratchet teeth 1, a pawl disk 2 on which a plurality of pawls 3 are mounted, which can be supported by bearings 15 therebetween. It is also ensured that the ratchet 1 and the pawl disk 2 can rotate coaxially. The pawl 3 is of a unitary structure, divided into a head portion 9, a shaft portion 10 and a tail portion 11 having a shaft hole 12 according to a function, and the head portion 9 includes a contact end 8 having a contact surface 13, the width of the contact end being greater than The widths of the shaft portion 10 and the tail portion 11 are generally "T" shaped as shown in Fig. 6. The pawl 3 is rotatably supported on the pawl disk 2 by the shaft pin 4. The pawl disk ≤ is disposed coaxially with the ratchet wheel 1, and the pawl 3 can be properly engaged with the ratchet teeth 7 by the resetting device, and the resetting device can be The suction of the magnet or the pulling force of the spring acts on the tail of the pawl 3, so that the rotation of the pawl 3 facilitates the engagement with the ratchet 7.

 The resetting device of the ratchet 3 can be spring or magnet as needed. In a preferred embodiment, the pawl '3 is reset by the magnet 6, and the pawl 3 should be made of a ferromagnetic material such as steel. Each of the magnets 6 is preferably embedded in the interior of the mounting sleeve 5 and fixed to the pawl disk 2, opposite to but not in contact with the tail portion 11 of the pawl 3, so that the magnetic attraction force is maximized. Made of non-magnetic material. The pawl 3 is subjected to heat treatment to increase the surface hardness of the contact surface 13 and the shaft hole 12 while ensuring that the material inside the structure of the pawl 3 maintains corresponding toughness.

As shown in FIG. 6, the position of the center of gravity of the pawl 3 can be adjusted as needed. When the overrunning clutch is used for frequent meshing conditions, the position of the center of gravity of the pawl 3 should be such that the torque generated by the centrifugal force is less than the reset torque of the resetting device. Preferably, the torque direction is the same; when the overrunning clutch is used for a long time to exceed the working condition, the center of gravity of the pawl 3 should be such that the torque generated by the centrifugal force is greater than the reset torque of the reset device, and the torque direction is opposite. In this way, beyond The clutch can flexibly engage or disengage the pawl 3 depending on the interaction requirements of the restoring force and the centrifugal force. ·

 The head portion 9, the shaft portion 10 and the tail portion 11 of the pawl 3 have a "T" shape in plan view, and the width of the contact end 8 is larger than the width of the remaining portion of the pawl 3, on the one hand, the wide portion thereof and the pawl disk 2 The corresponding structure is used for the limit of rotation of the pawl 3, ensuring that the tail portion 11 of the pawl 3 is not in contact with the ratchet teeth 7; on the other hand, increasing the contact area when the contact surface 13 is engaged with the ratchet teeth 7, reducing the compressive stress, The stress levels of the pawl and the shaft pin are equivalent, and the optimized structural design is achieved. A substance having a density greater than the density of the pawl material may be embedded in the pawl 3 to adjust the position of the center of gravity of the pawl 3.

 In order to improve the engagement accuracy of the clutch, the number of the pawls 3 and the number of the ratchets 7 are mutually prime. At least one pawl engages the ratchet each time to transmit torque. Depending on the actual use requirements, the clutch engagement accuracy (return angle) or torque can be effectively changed by changing the number and structure of the pawl 3 or the ratchet 7. When the number of the pawl 3 and the ratchet 7 is increased, the structural dimensions of the pawl 3 and the ratchet 7 are correspondingly reduced, and the transmission torque is also lowered; when the number of the pawl 3 and the ratchet 7 is reduced, the pawl 3 and The structural size of the ratchet 7 is correspondingly increased, and the transmission torque is also increased.

 As shown in Fig. 5, the angle between the tail portion and the head portion of the pawl structure is different according to the specific use requirements, and the purpose is to maximize the force of the reset device on the tail of the pawl, and the pawl head can flexibly flex with the ratchet Engage or disengage. When the pawl disk is in the inner ring, the angle is relatively small; when the pawl disk is in the outer ring, the angle is relatively large.

A guide groove 14 may be provided on the inner surface of the pawl 3 shaft hole 12 as shown in Fig. 6 to facilitate lubrication of the shaft pin to minimize wear. The matching clearance between the shaft hole 12 and the axle pin 4 should minimize the impact of the pawl 3 on the axle pin 4 when engaged, and at the same time ensure that the rotation of the pawl 3 is flexible. As an embodiment of the present invention, the ratchet 1 is disposed inside as shown in Fig. 1, and the pawl disk 2 is disposed outside the ratchet 1, and the structure is suitable for a gas turbine-like starting condition, a ratchet and a starter drive. The shafts are connected and the pawl disk is connected to the driven shaft of the turbine. Under the action of the starter, after the gas turbine starts and reaches a certain speed, the pawl of the clutch maintains the disengagement state from the ratchet under the action of the centrifugal force, and avoids the frequent meshing of the pawl and the ratchet to cause wear.

 As another embodiment of the present invention, as shown in Fig. 3, the ratchet 1 is disposed outside, and the pawl disk 2 is disposed inside the ratchet 1, and the structure is suitable for a condition similar to the frequent engagement of the pumping unit, the ratchet and The pulleys are connected and the pawl disk is connected to the motor drive shaft. The number of pawls and the number of ratchets are prime numbers. When engaged, each pawl has a pawl that engages with the ratchet, extending the life of the clutch.

 Figure 7 shows the pawl's complete disengagement from the ratchet, where the pawl tail cannot contact the ratchet.

Claims

Rights request 1. A ratchet overrunning clutch comprising a ratchet provided with a ratchet, a pawl disc provided with a pawl and a resetting device thereof, bearing support between the two to ensure that the ratchet and the pawl disk can rotate coaxially The pawl structure is a unitary structure, which is divided into three parts: a head portion, a shaft portion and a tail portion. The pawl head portion includes a contact end having a contact surface, and the pawl shaft portion is rotatably mounted on the pawl plate by a shaft pin, the spine The claw tail portion is disposed corresponding to the resetting device to receive the force of the resetting device, and is characterized in that: the pawl structure has a "T" shape in plan view, and the width of the head contact end of the pawl structure is greater than the width of the shaft portion and the tail portion.  2. The ratcheting overrunning clutch according to claim 1, wherein: the number of the pawls and the number of ratchets are prime numbers, and the pawl is embedded with a substance having a density greater than the density of the pawl material. To adjust the position of the center of gravity of the pawl structure:  3. The ratchet overrunning clutch according to claim 1, wherein: said pawl resetting means employs a magnet fixed to the pawl disk, corresponding to said pawl tail portion such that the magnet is opposite to the pawl tail portion The magnetic force is the largest, and it cannot contact the tail of the pawl under normal working conditions.  The ratchet overrunning clutch according to claim 3, wherein the magnet is disposed in a mounting sleeve made of a non-magnetic material, and both are fixed to the pawl disk. The ratchet overrunning clutch according to claim 1 or 2, wherein: the ratchet is disposed inside the clutch as an inner ring structure, and the pawl disk is disposed outside the ratchet as an outer ring structure, Rotate in coaxial.  The ratchet overrunning clutch according to claim 1 or 2, wherein: the ratchet is disposed outside the clutch as an outer ring structure, and the pawl disk is disposed inside the ratchet as an inner ring structure, both Rotate in coaxial.