CN221068357U - Bicycle crank dabber connection structure - Google Patents

Abstract

The utility model discloses a bicycle crank core shaft connecting structure, wherein a fixing hole for locking a core shaft is formed in the end part of a crank, the core shaft is inserted into the fixing hole to be fixed so as to rotate along with a crankshaft, the fixing hole is of a stepped double-layer structure, and the core shaft is axially engaged and locked by a fastener after being inserted into the fixing hole. On the one hand, set up the double-deck hole structure that the internal diameter is different in the fixed orifices, utilize the interhole transition step to constitute a usable fastener with dabber presss from both sides the fixed position of fastening, two-layer hole site structure is used for fixed shield and dabber respectively, promotes space utilization and has simplified the fixed knot between dabber and the bent axle and construct, has still improved life simultaneously.

Description

Bicycle crank dabber connection structure

Technical Field

The utility model relates to the field of bicycle crankshafts, in particular to a bicycle crank spindle connecting structure.

Background

Fig. 1 shows a detachable connection of a conventional crank and a spindle. A fixing hole 24 is usually formed by tapping a core shaft connecting end 21 of the crank 20, a separating groove 22 is formed on one side of the fixing hole 24, a clamping type fixing structure is formed, and opposite drilling and tapping are performed on crank parts on two sides of the separating groove 22. When the mandrel 10 is assembled, the mandrel 10 is inserted into the fixing hole 24, then screwed into the clamping hole 23 through the bolt 3 for locking, and finally the buckle type dust plug 1 is plugged through pre-tightening and cross locking. The existing locking structure has the following defects:

1. The end of the crank 10 is subjected to tapping, slotting and drilling at two sides, so that the strength is reduced, the size of the big end is required to be increased, the wall thickness and the weight of the part are increased, and the lightweight principle is not met.

2. In order to meet the requirement of light weight, the mandrel 10 is usually hollow and has a relatively thin wall thickness. Because the securing holes 24 are snap-in, the mandrel 10 is at risk of being deformed by force or fatigue failure. Once the mandrel 10 is deformed, the new fitting cannot be detached and replaced if it is light, breakage is caused if it is heavy, and safety is affected if the vehicle falls.

3. Most of the dust plugs 1 in the market are made of plastic materials, and are easy to damage or lose after being assembled and disassembled for many times. If the dust plug 1 is missing, dust, sundries, water and the like can enter the joint of the mandrel 10 and the crank 20, and the service life of the joint is affected.

Disclosure of utility model

In order to overcome the above-mentioned drawbacks of the prior art, an object of the present utility model is to provide a connecting structure for a crank spindle of a bicycle, which simplifies the fixing structure between the crank and the spindle.

In order to achieve the above purpose, the technical scheme adopted by the utility model is as follows:

A fixing hole for locking a mandrel is formed in the end portion of a crank, the mandrel is inserted into the fixing hole to be fixed in order to rotate along with a crankshaft, the fixing hole is of a stepped double-layer structure, and the mandrel is axially engaged and locked by a fastener after being inserted into the fixing hole.

Further, the double-layer structure is composed of a second through hole and a first through hole which are adjacently connected but have unequal inner diameters, a positioning step is arranged at the joint of the second through hole and the first through hole, a stop part extending towards a hole core is arranged on the positioning step, and the mandrel is inserted into the second through hole and is locked on the stop part through a fastener.

Further, an internal thread is formed on the end part, connected with the second through hole, of the mandrel, and the fastening piece penetrates through the blocking part to be meshed with the mandrel for locking.

Further, a convex key is arranged on the inner wall of the second through hole, and a structure matched with the convex key is also arranged at the end part of the mandrel, so that the mandrel can not rotate when inserted into the second through hole.

Further, the device further comprises a dust cover fixed on the first through hole, and the dust cover covers the end part of the mandrel.

Further, an internal thread is also arranged on the hole wall of the first through hole, and the dust cover is a threaded dust cover.

Further, a gasket for preventing excessive extrusion is further arranged between the dust cover and the fastener.

Further, the stop portion is a retainer ring fixed on the positioning step.

Furthermore, the retainer ring is welded and fixed with the positioning step.

The utility model has the beneficial effects that:

According to the connecting structure of the bicycle crank spindle, on one hand, the double-layer hole structures with different inner diameters are arranged in the fixing holes, the transition steps among the holes are used for forming a fixing position capable of clamping and fixing the spindle by using the fastener, the two-layer hole structure is respectively used for fixing the dust cover and the spindle, the space utilization rate is improved, the fixing structure between the spindle and the crankshaft is simplified, and meanwhile the service life is prolonged.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below.

Fig. 1 is a prior art schematic.

Fig. 2 is an enlarged view of a portion of the end of the crankshaft of the present utility model.

Fig. 3 is a sectional view of the assembled utility model.

Detailed Description

In the description of the present utility model, it should be noted that the directions or positional relationships indicated by the terms "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, and the above description is for convenience of description of the present utility model to simplify the description, rather than to indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model.

In the description, an element is referred to as being "on," "fixed" to, "connected" to another element, which may be directly on, fixed to, connected to or contacting the other element, or intervening elements may be present.

Exemplary embodiments of the present application will be described below with reference to the accompanying drawings. It should be understood, however, that the application may be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide yet additional embodiments. Throughout the drawings, like reference numbers indicate identical or functionally identical elements.

Referring to fig. 2 and 3, a connecting structure of a crank spindle of a bicycle is shown, a fixing hole for locking the spindle 10 is formed on a spindle connecting end 21 of a crank 20, and the fixing hole is a double-layer structure formed by a first through hole 25 with a larger inner diameter and a second through hole 26 with a smaller inner diameter. A transitional positioning step 27 is provided between the second through hole 26 and the first through hole 25, and a retainer ring 29 having a through hole in the middle is fixed to the positioning step 27 by welding, and the through hole inner diameter of the retainer ring 29 is slightly smaller than the second through hole 26 inner diameter (which is approximately equal to the outer diameter of the mandrel 10) and the maximum outer diameter of the fastener 5. The end of the mandrel 10 is tapped with the internal thread 4 inwards in the axial direction, the mandrel 10 is inserted into the second through hole 26 from one side, the fastener 5 is screwed into the mandrel 10 from the side of the first through hole 25 to be engaged and fixed with the thread structure of the end of the mandrel 10, and the mandrel 10 is fixed on the retainer ring 29. The dust cap 2 is fixed in the first through hole 25 so as to partially cover the fixed structure of the spindle 10.

In one embodiment of the present utility model, the hole wall of the first through hole 25 is also provided with an internal thread 4, and the dust cover 2 can be screwed into the threaded dust cover fixed in the first through hole 25. Since a part of the fastener 5 is accommodated at the bottom of the first through hole 25, a gasket 6 is further arranged between the dust cover 2 and the fastener 5, so that the parts are prevented from being damaged due to excessive extrusion of the two.

In one embodiment of the present utility model, the hole wall of the second through hole 26 is provided with a protruding key 28 in a surrounding manner, and the joint surface of the mandrel 10 and the second through hole 26 is also provided with a structure matched and jointed with the protruding key 28, so that the mandrel 10 is inserted into the second through hole 26 and limited by the protruding key 28, and relative rotation is prevented.

Claims (9)

1. The connecting structure of the crank core shaft of the bicycle is characterized in that the fixing hole is of a stepped double-layer structure, and the core shaft is axially engaged and locked by a fastener after being inserted into the fixing hole.

2. A bicycle crank spindle connection according to claim 1, wherein the double-layer structure is composed of a second through hole and a first through hole which are adjacently joined but have unequal inner diameters, a positioning step is provided at the junction of the second through hole and the first through hole, a stopper portion protruding toward the hole center is provided on the positioning step, and the spindle is inserted into the second through hole and is locked to the stopper portion by a fastener.

3. A bicycle crank spindle connection structure as claimed in claim 2, wherein the end of the spindle connected to the second through hole is provided with an internal thread, and the fastener passes through the stop portion to be engaged with the spindle for locking.

4. The bicycle crank spindle connecting structure according to claim 2, wherein a protruding key is arranged on the inner wall of the second through hole, and a structure matched with the protruding key is also arranged at the end part of the spindle, so that the spindle cannot rotate when being inserted into the second through hole.

5. A bicycle crank spindle connection according to claim 2, further comprising a dust cover secured to the first through hole, the dust cover covering the spindle end.

6. The bicycle crank spindle connection structure of claim 5, wherein the wall of the first through hole is also provided with an internal thread, and the dust cover is a threaded dust cover.

7. A bicycle crank spindle connection as claimed in claim 5, wherein a washer is further provided between the dust cap and the fastener to prevent over-extrusion.

8. A bicycle crank spindle connection as claimed in claim 2, wherein the stop portion is a retainer ring secured to the positioning step.

9. A bicycle crank spindle connection as claimed in claim 8, wherein the retaining ring is welded to the locating step.