JP3176508B2 - Chainsaw - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chainsaw,
In particular, the present invention relates to a chain saw provided with an oil pump for supplying lubricating oil to a saw blade chain.

[0002]

2. Description of the Related Art In general, a chain saw is provided with an oil pump for smoothing the movement of a saw blade chain, and lubricating oil is supplied to the saw blade chain. As such an oil pump for a chain saw, a so-called rotary plunger type oil pump is used, in which a plunger reciprocating in a cylinder forming a pump chamber rotates around its central axis and is reciprocated in the cylinder by the rotation. At the same time, a technique in which oil supplied from an oil pump is supplied from a discharge port of a discharge pipe to an oil supply port provided in a guide bar of a saw blade chain has been disclosed in, for example, Japanese Utility Model No. As described in JP-A-5-18088 and the like, it is well known in the related art.

[0003]

In the conventional oil pump for a chain saw, for example, when the position of the oil pump is lower than the oil supply port of the guide bar, the operation is left for a while after the operation of the oil pump. In this case, the oil remaining in the discharge pipe may flow back into the oil pump. At the time of this backflow, metal powder or dust such as iron powder on the surface of the guide bar or residual powder obtained by sharpening the saw blade chain may be mixed into oil and enter the oil pump. If the operation of the oil pump is resumed as it is, metal powder and dust are caught between the cylinder and the plunger of the oil pump, which not only causes power loss and noise, but also damages surrounding members and causes durability. There is a problem that various troubles such as remarkably impairing the performance are caused. Therefore, maintenance work such as replacement of a plunger and a cylinder, which is extremely troublesome, must be performed frequently, and there is a problem in that work efficiency is reduced and cost is increased.

The present invention has been made in view of such a conventional problem, and has as its object to prevent, in particular, entry of metal powder and dust into an oil pump due to backflow of oil. Thus, a chain saw oil pump that can prevent power loss and noise, improve the durability of the oil pump, is economically advantageous, and does not reduce work efficiency. To provide.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, a chain saw according to the present invention discharges lubricating oil for a saw blade chain from an opening groove defined by a substantially elliptical exposed end face of a discharge pipe. Equipped with an oil pump
From the bottom of the opening groove, the bottom of the opening groove is sealed in a direction that blocks the flow of oil, and a small gap is provided between the opening groove and the extension of the exposed end surface so as not to hinder the flow of oil. It is characterized by having been erected.
As a more preferable specific example, a filter provided at the most upstream portion of the opening groove can be cited.

[0006]

[Operation] In the chain saw according to the present invention configured as described above, the oil remaining in the opening groove of the discharge pipe may fall into the oil pump between the end of the operation of the oil pump and the restart of the operation. Even if an attempt is made to reverse the flow, the metal powder and dust mixed in the oil are temporarily stored in the compartment formed by the backflow prevention wall, and are collected by, for example, adhering to the inner surface of the opening groove. And is prevented from entering the oil pump.

[0007]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cutaway cross-sectional view of a main part of a chain saw according to one embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view taken along the line II-II of FIG. Chain saw saw blade chain (not shown)
The illustrated oil pump 1 for supplying lubricating oil to the engine is of a rotary plunger type, and its casing 2 is disposed adjacent to a lubricating oil tank (not shown) of a chain saw main body. I have. A drive shaft 4 of a motor (not shown) is rotatably inserted into the casing 2, and a worm 3 is fixed to the drive shaft 4 so as to be integrally rotatable therewith.

On the other hand, a plunger 6 having a worm wheel portion 5 meshing with the worm 3 is provided on the casing 2.
Are provided rotatably and slidably in the axial direction in the internal space 7 formed in the inner space. The worm wheel portion 5 is made of a suitable synthetic resin material, and is integrally molded coaxially with the plunger 6 using a commercially available needle roller machined with a suitable metal material with high precision. I have. A bearing 8 formed of a cylindrical steel material is fitted and fixed in the internal space 7. One of the shaft portions 61 extending from the worm wheel portion 5 to the one end side of the plunger 6 is extended in the axial direction so that the bearing 8
The pump section 20 of the oil pump 1 is configured by projecting from the section. A cut-out portion 61 a formed by additionally processing a needle roller used as the plunger 6 is provided at the tip of the one shaft portion 61. On the other hand, the plunger 6 has a cam portion 62a formed of an inclined surface formed at the tip end portion of the other shaft portion 62 extending coaxially with the worm wheel portion 5 on the opposite side of the pump portion 20.

A guide pin 12 projecting into the internal space 7 is implanted in the casing 2, and an inner end of the guide pin 12 is connected to the cam portion 62 of the plunger 6.
a. Further, a compression coil spring 22 is interposed between the inner end 8a of the bearing 8 and the worm wheel portion 5, and the compression coil spring 22 connects the cam portion 62a of the plunger 6 to the pin 12 Is pressed so as to be pressed.

The pump portion 20 has an inlet opening 31 and an outlet opening 32 formed in a pump chamber 30 formed between the front end portion of the plunger 6 and a peripheral wall portion facing the diametrical direction. I have. The opening of the outer end 8b of the casing 2 is closed by fitting and fixing a plug member 8c formed of an elastic material such as rubber in a liquid-sealed state. At the inlet opening 31, the pump chamber 30 is connected to a lubricating oil tank (not shown) by a flexible tube 25 fitted and connected in a liquid-sealed state to an inlet nipple 34 formed integrally with the casing 2. on the other hand,
The outlet nipple 35 integrally formed with the outlet opening 32 is connected to a cylindrical connecting portion 41 formed at an upstream end of a discharge pipe 40 described later in a liquid-sealed state.

Next, the details of the discharge pipe 40 will be described. FIG. 3 shows the discharge pipe 4 integrally connected to the oil pump 1 and made of oil-resistant synthetic rubber or the like.
FIG. 4 is a perspective view showing the entirety of an example of FIG.
FIG. 5 is a sectional view taken along the line VV in FIG. The illustrated discharge pipe 40 has a substantially U-shaped cross-sectional shape, and has a boat bottom-shaped discharge pipe body 42 as a whole,
The upstream end of the discharge pipe main body 42 (the oil pump 1)
(The outlet nipple 35 side).

The opening of the discharge pipe main body 42 is defined by a substantially elliptical exposed end surface 43 and extends in the vertical direction and has a tapered side wall with respect to the bottom 44a (see FIG. 5). 44 are formed. Then, a plurality of backflow prevention walls 45, 4 made of plate-like tongues are formed from the bottom 44 a of the opening groove 44 in a direction (direction in which oil flows) orthogonal to the length direction (oil flowing direction).
5, ... are erected. As can be seen from FIG. 5, the backflow prevention walls 45, 45,.
4a is sealed, and a small gap (for example, about 1 mm) is provided between the exposed end face 43 and the extension line so as not to hinder the oil flow, so that the lubricating oil can be discharged. At the upstream end of the opening groove 44 (on the side of the connection portion 41), a mesh filter 46 for filtering and removing metal powder, dust, etc., which does not hinder oil flow, is provided. The flow path in the connection part 41 also
It is preferable that the thickness be as small as possible and the backflow prevention effect is improved.

The discharge pipe 40 thus constructed
Is connected to the outlet nipple 35 of the oil pump 1 and communicates with the discharge side of the oil pump 1. FIG.
As shown in FIGS. 2 and 3, the exposed end face 43 of the discharge pipe 40 is pressed from behind by a main body portion of a chain saw (not shown), and thereby overlaps with the mounting seat surface 51 of the guide bar 50 for guiding the running of the saw blade chain. In a liquid-sealed state on the side plate 51a,
Reference numeral 4 communicates with an oil supply port 53 of the guide bar 50 through an elongated opening 52 formed in the side plate 51a.

Next, the operation of the oil pump of the chain saw according to the embodiment of the present invention will be described. When the worm 3 is rotated by a driving force from a motor (not shown), the worm wheel portion 5 meshing with the worm 3 is reciprocated in the axial direction together with the plunger 6 while rotating. This reciprocation is caused by the cam 62
a within the range set by the guide pin 12 and thereby the one shaft 6 of the plunger 6
The volume of the pump chamber 30 is increased or decreased by the reciprocating motion of one tip. During the pump operation, during the suction stroke in which the volume of the pump chamber 30 increases, the outlet opening 32 is closed by the peripheral surface of the distal end of the plunger 6 without the notch 61a, but the inlet opening 31 is closed by the plunger 6. The notch portion 61a formed at the tip of the one shaft portion 61 communicates with the inside of the pump chamber 30 so that the lubricating oil in the lubricating oil tank passes through the flexible pipe 25 and the inlet opening 31. Through the pump chamber 30
It is sucked in.

On the other hand, during the discharge stroke in which the volume of the pump chamber 30 decreases, the one shaft portion 61 of the plunger 6 whose inlet opening 31 has changed its position by rotation.
Although closed by the tip, the outlet opening 32 communicates with the pump chamber 30 through the cutout portion 61a, and therefore, the lubricating oil in the pump chamber 30 flows from the outlet opening 32 to the opening groove in the discharge pipe 40. The oil is supplied to the saw blade chain guide groove 55 through the oil supply port 53 of the guide bar 50 to lubricate the saw blade chain.

After the operation of the oil pump 1 is completed and before the operation is restarted, the oil remaining in the opening groove 44 of the discharge pipe 40 is removed by the oil pump 1.
May flow back into the interior. If metal powder or dust such as iron powder or residual powder after grinding of the saw blade chain adheres to the surface of the guide bar 50 and enters the oil pump 1 in the backflow oil, as described above. There is a possibility that various troubles may occur. However, such metal powder, dust, and the like may not be covered by the backflow prevention wall 4 provided in the opening groove 44.
The oil is temporarily stored in a compartment formed by partitioning the opening groove 44 by 5, 45,..., And is removed, and is also filtered by the filter to enter the oil pump 1. Is blocked. In addition,
Since a plurality of backflow prevention walls 45 are provided, the guide bar 50
There is no problem even if the position of the oil supply port 53 changes depending on the type of the oil supply port.

As described above, one embodiment of the present invention has been described in detail. However, the present invention is not limited to the above-described embodiment, and various designs may be made without departing from the present invention described in the appended claims. It is possible to make changes. For example, in the illustrated example, an example in which a rotary plunger type oil pump is used as the oil pump is shown. However, for example, a gear type or diaphragm type oil pump may be used.

[0018]

As will be understood from the above description, according to the present invention, the occurrence of power loss and noise is prevented by preventing metal powder and dust from entering the oil pump due to the backflow of oil. Can be prevented, and while improving the durability of the oil pump, it is economically advantageous,
In addition, a decrease in work efficiency can be prevented.

[Brief description of the drawings]

FIG. 1 is a cutaway cross-sectional view of a main part of a chainsaw according to one embodiment of the present invention.

FIG. 2 is a vertical sectional view taken along the line II-II in FIG.

FIG. 3 is a perspective view of a discharge pipe of an oil pump applied to the present invention.

FIG. 4 is a front view as seen from the direction of arrow IV in FIG. 3;

FIG. 5 is a sectional view taken along the line VV in FIG. 4;

[Description of Signs] 1 ... Oil pump 40 ... Discharge pipe 44 ... Opening groove 44a ... Bottom of opening groove 45 ... Backflow prevention wall 46 ... Filter

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 51-146599 (JP, U) JP-A 5-58251 (JP, U) JP-A 59-43101 (JP, U) JP-A 62- 178105 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B27B 17/12

Claims (2)

(57) [Claims] A chain saw having an oil pump (1) for discharging lubricating oil for a saw blade chain from an opening groove (44) defined by a substantially elliptical exposed end surface (43) of a discharge pipe (40). In the above, between the bottom (44a) of the opening groove (44) and the bottom (44a) of the opening groove (44) in a direction in which oil flow is blocked, and between the bottom (44a) and the extension of the exposed end face (43). A chain saw characterized in that backflow prevention walls (45, 45, ...) are provided upright with small gaps in a range not obstructing oil flow. 2. The chainsaw according to claim 1, wherein a filter (46) is provided at a most upstream portion of the opening groove (44).