Lock washer

Abstract

The utility model discloses a kind of lock washer, it relates to mechanical engineering technical field, mainly solve the problem of low lock washer lock ability. The technical scheme that is adopted is that the outer conical surface of disc spring is connected with limit buckle, limit buckle is evenly distributed along the outer conical surface circumference of disc spring, limit buckle can limit the rotation of hexagonal head bolt or hexagon nut, the depth of limit buckle is about one sixth of the height of hexagonal head or hexagon nut of bolt, limit buckle does not affect the use of various wrenches to tighten bolt. Small lock inclined tooth is connected on the inner conical surface of disc spring, it is evenly distributed along the inner conical surface circumference of disc spring, when disc spring is pressed flat, small lock inclined tooth is embedded fastener, prevent bolt connection loose. The utility model has good lock ability, its elasticity is big, intensity is high, cost is low, safe and reliable, can be repeatedly used, suitable for various grades of hexagonal head bolt connection.

Description

Technical Field

[0001] This utility model relates to the field of mechanical engineering technology, and in particular to an anti-loosening washer for preventing hexagonal head bolt connections from loosening. Background Technology

[0002] Hex head bolts are widely used in various industries such as vehicles, ships, railways, aviation, weaponry, and construction. When using hex head bolts, spring washers are generally used to prevent loosening, but spring washers have low anti-loosening ability.

[0003] Experiments show that when using a 20mm spring washer and an 8.8 grade M20 hexagonal head bolt with a preload torque of 320 Nm, the spring washer is completely flattened when the tightening torque exceeds 20 Nm. At this point, the sharp angle at the bevel of the spring washer cannot engage with the fastener or the fastened component, and the spring washer loses its anti-loosening capability. As the 320 Nm preload torque slowly decreases to below 20 Nm, the spring washer begins to prevent loosening, but by then, the 20 Nm tightening torque has already lost its tightening effect. Improper installation can also cause the spring washer to expand from the bevel, posing a safety hazard. NASA states in its fastener design manual that once the bolt is fully tightened, the spring washer is flattened, becoming essentially a solid flat washer and losing its anti-loosening capability.

[0004] A search revealed the Nord Lock anti-loosening washer, invented by the Swedish company Nordlock. It consists of two identical circular washers, one with radial serrations on one plane and wedge-shaped teeth on the other. The wedge-shaped teeth of the two washers interlock to form the Nord Lock anti-loosening washer. When tightened, the radial serrations embed into the fastener and the fastened component, making it difficult to loosen. Because the wedge angle of the wedge-shaped teeth is greater than the thread helix angle, any misalignment or lifting of the wedge-shaped teeth increases the bolt's tightening force, thus preventing the bolt connection from loosening. While the Nord Lock anti-loosening washer offers good anti-loosening performance, it requires machining the radial serrations and wedge-shaped teeth, resulting in high manufacturing costs and an expensive price. Furthermore, it cannot be reused.

[0005] Another type of locking nut, invented by Hard Lock Industries, Ltd. of Japan, consists of a convex nut with an outer cone and a concave nut with an inner cone. The convex nut is the main nut, and the concave nut is the auxiliary locking nut, used in pairs. The center of the outer cone of the convex nut is eccentric to the center of the thread, while the center of the inner cone of the concave nut is not eccentric to the center of the thread. When the concave nut is tightened, the outer cone of the convex nut and the inner cone of the concave nut wed each other, generating a large wedging force. This wedging force acts on the threaded pair simultaneously, preventing the threaded pair from loosening. It has a good locking effect. However, Hard Lock locking nuts are difficult to manufacture, have high manufacturing costs, are expensive, and excessive tightening torque can damage the threads. Utility Model Content

[0006] The anti-loosening washer provided by this utility model aims to improve the anti-loosening capability of hexagonal head bolt connections, prevent the hexagonal head bolt connections from loosening, and prevent safety accidents. To achieve the above objectives, the following technical solution is adopted:

[0007] The outer conical surface of the disc spring is connected to a limiting buckle, which is evenly distributed along the circumference of the outer conical surface. Inserting the hexagonal head of the bolt or hexagonal nut into the limiting buckle restricts its rotation. The depth of the limiting buckle is approximately one-sixth of the height of the hexagonal head of the bolt or hexagonal nut, so it does not affect the use of various wrenches to tighten the bolt. Because the limiting buckle only bears a small portion of the preload torque, the preload torque will not damage it. Small anti-loosening helical teeth are connected to the inner conical surface of the disc spring, evenly distributed along its circumference. When the hexagonal head bolt or hexagonal nut is tightened, the disc spring is flattened, and the small anti-loosening helical teeth embed into the fastened part. At this time, the anti-loosening washer effectively prevents the hexagonal head bolt connection from loosening.

[0008] Disc springs have relatively low elasticity and strength when compressed. To increase the elasticity and strength of the anti-loosening washer, since the elasticity of a disc spring when compressed is proportional to the product of the cube of its thickness and the amount of deformation, appropriately increasing the thickness of the disc spring significantly increases its elasticity and strength. However, this increased thickness causes the calculated stress at point 0M on the upper surface of the disc spring to exceed the yield strength of the spring material. To reduce this calculated stress, since the calculated stress at point 0M on the upper surface of the disc spring is proportional to the product of its thickness and the amount of deformation, appropriately reducing the amount of deformation during compression ensures that the calculated stress at point 0M on the upper surface of the disc spring remains below the yield strength of the spring material.

[0009] By adopting the above technical solution, this utility model has the following beneficial effects compared with the prior art:

[0010] 1. Anti-loosening washers have excellent anti-loosening ability, high elasticity, and high strength, and are suitable for hexagonal head bolt connections of various grades.

[0011] 2. Anti-loosening washers can be stamped and formed, with low manufacturing cost, safety and reliability, and can be reused. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the operation of the anti-loosening washer in an embodiment of this utility model.

[0013] Figure 2 These are the top view, sectional view, and bottom view of the anti-loosening washer in the embodiments of this utility model. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to the accompanying drawings and examples:

[0015] Figure 1 The anti-loosening washer 4 shown has the following structure: Figure 2 As shown, a limiting buckle 1 is connected to the outer conical surface of the disc spring 2. The limiting buckles 1 are evenly distributed along the circumference of the outer conical surface of the disc spring 2. When the hexagonal head 7 of the bolt or the hexagonal nut 5 is inserted into the limiting buckle 1, the limiting buckle 1 restricts the rotation of the hexagonal head 7 of the bolt or the hexagonal nut 5. The depth of the limiting buckle 1 is about one-sixth of the height of the hexagonal head 7 of the bolt or the hexagonal nut 5, so the limiting buckle 1 does not affect the use of various wrenches to tighten the bolt. Because the limiting buckle 1 only bears a small portion of the preload torque, the preload torque will not damage the limiting buckle 1. Small anti-loosening helical teeth 3 are connected to the inner conical surface of the disc spring 2. They are evenly distributed along the circumference of the inner conical surface of the disc spring 2. When the hexagonal head 7 of the bolt or the hexagonal nut 5 is tightened, the disc spring 2 is flattened, and the small anti-loosening helical teeth 3 are embedded in the fastened part 6. At this time, the anti-loosening washer 4 can effectively prevent the bolt connection from loosening. Experiments show that the anti-loosening washer has a good anti-loosening effect.

[0016] In other embodiments of this invention, the deformation of the disc spring 2 when it is compressed can be set to zero, and the disc spring 2 is equivalent to a flat washer.

Claims

1. An anti-loosening washer, characterized in that... The outer conical surface of the disc spring (2) is connected to a limiting buckle (1). The limiting buckle (1) is evenly distributed along the circumference of the outer conical surface of the disc spring (2). The limiting buckle (1) can restrict the rotation of the hexagonal head (7) of the bolt or the hexagonal nut (5). The depth of the limiting buckle (1) is about one-sixth of the height of the hexagonal head (7) of the bolt or the hexagonal nut (5). The inner conical surface of the disc spring (2) is connected to a small anti-loosening helical tooth (3). The small anti-loosening helical tooth (3) is evenly distributed along the circumference of the inner conical surface of the disc spring (2).

2. The anti-loosening washer according to claim 1, characterized in that: The deformation of the disc spring (2) when compressed can be set to zero. The disc spring (2) is equivalent to a flat washer.

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