JP2004197699A - Recoil cranking motor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a recoil cranking motor device which makes it possible to prevent the coming off of a hook for a pressure accumulator spring and to enhance the durability of the hook, which is also excellent in assemblage capacity, and which is easily procured because of its low cost. <P>SOLUTION: The recoil cranking motor device is equipped with a rope reel, a return spring designed to wind back the rope reel, a driving pulley formed on the axis line of the rope reel and connected with the crank axis of an engine through a one-way clutch, and a pressure accumulator spring installed between the rope reel and the driving pulley. The pressure accumulator spring is fitted with a hook unit in its internal end portion, while the driving pulley has an almost round-shaped core unit on which the pressure accumulator spring is wound. In the core unit, an almost round recessed unit is formed, and in this recessed unit, a protrusion to which the hook unit of the pressure accumulator spring is to be connected, is built. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a recoil starter device.
[0002]
[Prior art]
FIG. 6 is a front sectional view of a chain saw 1 as an example of a machine provided with a recoil starter device. 6, a saw (not shown) is attached to the left end of the engine 2, and a cooling fan 4 attached to the crankshaft 3 and a recoil starter device 20 provided substantially coaxially are attached to the right side. The engine 2 is covered with an engine cover 5, and a recoil starter cover 21 that covers the recoil starter device 20 is attached to the engine cover 5. A rope reel 23 having a rope groove 24 and a driving pulley 40 are rotatably inserted into a shaft 22 provided inside the recoil starter cover 21, and a storage spring is provided between the rope reel 23 and the driving pulley 40. The outer end of the energy storage spring 400 is locked to the rope reel 23, and the inner end is locked to the drive pulley 40. The drive pulley 40 is connected to the crankshaft 3 via a one-way clutch (not shown).
[0003]
The rope 6 wound around the rope groove 24 is connected to the start knob 7. When the operator pulls the start knob 7, the rope reel 23 rotates to wind up the accumulation spring 400. The accumulation spring 400 gradually increases the torque of the driving pulley 40 while accumulating the rotational force. When the torque of the drive pulley 40 reaches a value at which the engine 1 can rotate, the engine 1 is rapidly driven to rotate by the energy stored in the energy storage spring 400 and starts, and the rope reel 23 is rewound by the return spring 25. . Therefore, the operator can start the engine 1 with a small operation force.
[0004]
FIG. 7 is a perspective view of a driving pulley 40 generally known in the related art. 7, the inner end of the energy storage spring 400 shown in FIG. 6, which applies a rotational force to the drive pulley 40, has a hook portion (not shown) formed in a substantially U-shape. It is inserted and locked by a substantially U-shaped locking portion 42 provided on the winding core 41.
[0005]
FIG. 8 is a plan view showing another example of the rope reel 50, the driving pulley 53, and the energy storage spring 500 stored in the rope reel 50. In FIG. 8, the inner end of the energy storage spring 500 that applies a rotational force to the driving pulley 53 includes a hook portion 501 formed in a ring shape, and the hook portion 501 is provided on the winding core portion 51 of the driving pulley 53. The energy storage spring 500 is inserted and locked in the substantially circular locking portion 52, and the energy storage spring 500 is used to prevent the hook portion 501 from coming off. It is formed so that at least a part thereof is brought into close contact (for example, see Patent Document 1).
[0006]
[Patent Document 1]
JP-A-2002-235638 (pages 1 to 7, FIG. 6)
[0007]
[Problems to be solved by the invention]
The inner end of the energy storage spring 400 for applying a rotational force to the drive pulley 40 shown in FIG. 6 has a hook portion formed in a substantially U shape, and the hook portion is a core portion of the drive pulley 40 shown in FIG. 41 is inserted and locked in the substantially U-shaped locking portion 42 provided in the hook 41, so that even if a force acts on the hook portion by the action of retracting from the retracting spring of the energy storage spring and reaching the open state, The part does not come off from the locking part 42 of the driving pulley. However, according to this locking method, the hook portion of the energy storage spring is fixed to the locking portion 42, so that the above operation causes an excessive repetitive stress in the hook portion, which easily causes fatigue failure. There is. In addition, since the energy storage spring 400 has an outer end attached to the rope reel 23 and an inner end hook attached to the drive pulley 40, the attachment is usually a relatively difficult operation. The operation of attaching the substantially U-shaped hook portion to the locking portion 42 further deteriorates the assembling workability.
[0008]
In FIG. 8, the inner end of the energy storage spring 500 that applies a rotational force to the driving pulley 53 includes a hook portion 501 formed in a ring shape, and the hook portion 501 is provided on the winding core portion 51 of the driving pulley 53. It is inserted and locked by a substantially circular locking portion 52. Accordingly, when a force is applied to the hook portion 501 by an operation from the entrainment of the energy storage spring 500 to the unwinding state and the open state, the hook portion moves and the force can be released, thereby avoiding the generation of excessive stress. As a result, the hook portion 501 is easily detached although the durability is excellent. Therefore, the energy storage spring 500 presses the hook portion 501 so as to prevent the energy storage spring 500 from coming off. Although it is manufactured by applying a special molding, there arises a problem that the manufacturing cost of the energy storage spring 500 increases and it becomes difficult to obtain it.
[0009]
SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to prevent a hook of a storage spring from coming off and to improve the durability, and it is excellent in assemblability, and inexpensive and easily available. It is intended to provide a starter device.
[0010]
Means for Solving the Problems, Functions and Effects
In order to achieve the above object, a first aspect of the present invention provides a rope reel, a return spring for rewinding the rope reel, provided on an axis of the rope reel, via a one-way clutch to an engine crankshaft. In a recoil starter device including a driving pulley to be coupled, and a power storage spring interposed between the rope reel and the driving pulley,
The energy storage spring has a hook portion at an inner end thereof, the drive pulley has a substantially circular core portion around which the energy storage spring is wound, and the core portion has a substantially arcuate concave portion. The concave portion is provided with a projection for locking the hook portion of the energy storage spring.
[0011]
According to the first invention, the energy storage spring has a hook portion at an inner end thereof, and the drive pulley has a substantially circular core portion around which the energy storage spring is wound. A substantially arcuate concave portion is formed, and a projection for locking the hook portion of the energy storage spring is provided in the concave portion. By inserting the hook portion of the energy storage spring into the projection, the hook is formed. Detachment can be prevented. Therefore, in order to hold the hook portion and to prevent the energy storage spring from coming off, special forming is performed such that at least a part of the second winding is brought into close contact with the first winding of the inner peripheral winding portion of the energy storage spring. Since it is not required, the manufacturing cost can be reduced.
[0012]
A second invention comprises the hook portion formed in a circular shape and the projection formed in a columnar shape, and the hook portion is locked to the driving pulley by inserting the hook portion into the projection. It is characterized by the following.
[0013]
According to the second invention, the hook portion is formed in the circular shape, and the projection formed in the column shape is provided, and the hook portion is inserted into the projection to lock the hook portion to the driving pulley. With this configuration, the hook portion and the protrusion can be easily processed, and the manufacturing cost can be reduced.
[0014]
A third invention is characterized in that a dimensional difference between the inner diameter of the hook portion and the outer diameter of the projection is formed larger than the dimensional difference between the inner diameter of the concave portion and the outer diameter of the hook portion.
[0015]
According to the third aspect, the dimensional difference between the inner diameter of the hook portion and the outer diameter of the projection is formed to be larger than the dimensional difference between the inner diameter of the concave portion and the outer diameter of the hook portion. When a force is applied to the hook portion by a normal operation from the retracting of the spring to the unwinding state to the open state, the hook portion moves, and the inner surface of the concave portion contacts the outer surface of the hook portion to move the hook portion. The inner surface of the circular hook portion does not come into contact with the outer surface of the cylindrical projection. For this reason, stress does not concentrate on the protrusion, and there is no breakage of the drive pulley and the hook portion coming off due to breakage of the protrusion. In addition, when the energy storage is released, the hook rotates around the projection and escapes the generation of local stress in the energy storage spring, so that the durability of the energy storage spring is improved.
[0016]
A fourth invention is characterized in that the protrusion is formed such that the height of the protrusion is lower than the height of the core.
[0017]
According to the fourth aspect, since the height of the protrusion is formed to be lower than the height of the core, the work of inserting the hook into the protrusion becomes easy, and the assembling workability is improved. Is further improved.
[0018]
In a fifth aspect, the protrusion is formed integrally with a clutch engagement shaft of the drive pulley.
[0019]
According to the fifth aspect, the projection is formed integrally with the clutch engagement shaft of the drive pulley, and is provided at a location on the bottom surface where the projection is provided with high rigidity, so that the projection is added to the projection. The deformation of the root of the projection due to the force is small, and the generated stress is low, so that the projection is hard to break, and the breakage of the driving pulley and the detachment of the hook of the energy storage spring can be prevented.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of a recoil starter device according to the present invention will be described in detail with reference to the drawings. The same components as those in the conventional example are denoted by the same reference numerals.
[0021]
FIG. 1 is a sectional view showing an example of a recoil starter device of a small engine. A rope reel 23 having a rope groove 24 and a driving pulley 30 are rotatably inserted into a shaft 22 provided inside the recoil starter cover 21, and a storage spring 300 is provided between the rope reel 23 and the driving pulley 30. The outer end of the energy storage spring 300 is locked by the rope reel 23, and the inner end is locked by the drive pulley 300. The clutch engagement shaft 30C of the drive pulley 30 is connected to the engine crankshaft 3 (indicated by a two-dot chain line) via a one-way clutch (not shown).
[0022]
When the rope 6 wound around the rope groove 24 is pulled, the rope reel 23 rotates and winds up the energy storage spring 300. The storage spring 300 gradually increases the torque of the driving pulley 30 while accumulating the rotational force. When the torque of the drive pulley 30 reaches a value at which the crankshaft 3 can be rotated, the crankshaft 3 is rapidly driven to rotate by the energy stored in the energy storage spring 300 to start the engine, and the rope reel 23 returns to the return spring 27. Rewind by Therefore, the operator can start the engine with a small operation force.
[0023]
FIG. 2 is a perspective view of the driving pulley 30 according to the present invention. The drive pulley 30 has a substantially circular core portion 31 around which the energy storage spring 300 shown in FIG. 4 is wound, and the core portion 31 has a substantially circular concave portion 33 and an arc of the concave portion 33. An engaging portion 32 composed of concentric columnar projections 34 is formed. Therefore, as shown in FIG. 4, the hook portion 301 formed at the inner end of the energy storage spring 300 and inserted into the locking portion 32 does not come off from the locking portion 32 due to the projection 34.
[0024]
In the drive pulley 30 shown in a sectional view in FIG. 3, the height h of the protrusion 34 is formed to be lower than the height H of the core 31. Therefore, the hook portion 301 formed at the inner end of the energy storage spring 300 shown in FIG. 4 can be easily inserted into the locking portion 32, and the assembling workability is improved. Further, as shown in FIG. 3, the projection 34 is continuously connected to the clutch engagement shaft 30C of the drive pulley 30, and is integrally formed. Therefore, the protrusion 34 is provided in a place with high rigidity in the range of the bottom surface 30T where the protrusion 34 is provided. As a result, the deformation of the root portion of the projection due to the force applied to the projection 34 is small, and the generated stress is low, so that the projection is less likely to break, and it is possible to prevent the drive pulley from being damaged and the hook portion of the energy storage spring from coming off. .
[0025]
FIG. 5 is an enlarged view of the locking portion 32 shown in FIG. In FIG. 5, the dimensional difference between the inner diameter d2 of the hook portion 301 and the outer diameter d1 of the projection 34 is formed larger than the dimensional difference between the inner diameter d4 of the recessed portion 33 and the outer diameter d3 of the hook portion 301. Accordingly, when a force is applied to the hook portion 301 by a normal operation from the winding of the accumulation spring 300 to the unwinding to the open state, the hook portion 301 moves, and the inner surface of the concave portion 33 comes into contact with the outer surface of the hook portion 301. Therefore, the inner surface of the circular hook portion 301 does not come into contact with the outer surface of the columnar projection 34.
[0026]
For this reason, no local stress is generated in the projection 34, the drive pulley 30 and the energy storage spring 300 are not damaged by the breakage of the projection 34, and the hook portion 301 does not come off. Since no force that causes deformation is applied, the durability is improved. When the energy storage is released, the hook portion 301 rotates about the projection 34 to avoid the occurrence of local stress in the energy storage spring 300, so that the durability of the energy storage spring 300 is improved.
[Brief description of the drawings]
FIG. 1 is a sectional view of a recoil starter device according to the present invention.
FIG. 2 is a perspective view of a driving pulley.
FIG. 3 is a sectional view of a driving pulley.
FIG. 4 is a plan view showing a driving pulley and a storage spring stored in the driving pulley.
FIG. 5 is a partially enlarged view of a locking portion of a driving pulley in which a hook portion of a storage spring is locked.
FIG. 6 is a front sectional view of a chain saw engine including a conventional recoil starter device.
FIG. 7 is a perspective view showing a conventional drive pulley.
FIG. 8 is a plan view showing a conventional driving pulley and a storage spring stored in the driving pulley.
[Explanation of symbols]
2 ... engine, 6 ... rope, 23 ... rope reel, 24 ... rope groove, 25 return spring, 30, 40, 50 ... drive pulley, 30C ... clutch engagement shaft, 31 ... core part, 32 ... locking part, 33 ... recessed part, 34 ... protrusion, 300, 400, 500 ... storage spring, 301 ... hook part.

Claims (5)

A rope spring, a return spring for rewinding the rope reel, a drive pulley provided on an axis of the rope reel, and coupled to a crankshaft of an engine via a one-way clutch, and a rope pulley and the drive pulley. In a recoil starter device including a power storage spring interposed therebetween, the power storage spring has a hook portion at an inner end thereof, and the drive pulley has a substantially circular winding around which the power storage spring is wound. A recoil starter device having a core portion, wherein a substantially arc-shaped concave portion is formed in the winding core portion, and a projection for locking the hook portion of the energy storage spring is provided in the concave portion. The method according to claim 1, further comprising: the hook portion formed in a circular shape; and the projection formed in a column shape, wherein the hook portion is locked to the driving pulley by inserting the hook portion into the projection. Item 2. A recoil starter device according to Item 1. The recoil starter according to claim 2, wherein a dimensional difference between an inner diameter of the hook portion and an outer diameter of the protrusion is formed to be larger than a dimensional difference between an inner diameter of the concave portion and an outer diameter of the hook portion. apparatus. 4. The recoil starter device according to claim 2, wherein the height of the projection is smaller than the height of the core. The recoil starter device according to claim 2, wherein the protrusion is formed integrally with a clutch engagement shaft of the drive pulley.

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