CN204322203U - Oil pump and portable work machine - Google Patents

Abstract

The utility model provides an oil pump and a portable working machine, which can accurately specify the maximum value of the amount of engine oil sprayed out per one stroke. By engaging the anti-dropping pin (14) provided on the adjusting shaft (15) with the inclined portion (12a) of the cover (12), the adjusting shaft (15) preloaded by the second spring (13) is prevented from falling from the cover. (12) SHUT OFF. When the adjusting shaft (15) is rotated relative to the cover (12), the anti-dropping pin (14) slides on the inclined portion (12a), and the axial position of the adjusting shaft (15) changes. The rotatable range of the adjustment shaft (15) with respect to the cover (12) is limited by the contact of the anti-drop pin (14) with the wall portions (12b) at both ends of the inclined portion (12a). The adjustment shaft (15) locks the pump gear shaft (10) by engaging the end face (15a) of the adjustment shaft (15) with the end face (10c) of the central shaft portion.

Description

Oil pumps and portable work machines

technical field

The utility model relates to an oil pump for supplying engine oil in portable working machines such as chain saws, and a portable working machine equipped with the oil pump.

Background technique

For example, in a chain saw, in order to prevent scorching of the saw chain, an oil pump supplies lubricating oil to the saw chain (Patent Document 1 below). The user of the saw chain adjusts the amount of oil sprayed on the saw chain according to the type of material to be cut and the like. In the plunger type oil pump, the discharge amount of the oil can be adjusted by adjusting the stroke of the pump gear shaft (plunger) reciprocating in the pump housing. For example, the stroke is adjusted by the rotation of an adjustment shaft that is screwed to the pump casing and locks the pump gear shaft.

Patent Document 1: Japanese Patent Laid-Open No. 2012-71486

In the structure in which the discharge amount of oil is adjusted by rotating the adjustment shaft screwed with the pump casing, if the adjustment shaft is retracted by a constant amount or more, the adjustment shaft will not engage with the pump gear shaft (variation) It has nothing to do with the determination of the stroke range of the pump gear shaft), and the maximum value of the discharge amount of oil per one stroke cannot be accurately determined. Therefore, the amount of injection per one stroke may become excessive, and the oil may disappear before the fuel is exhausted. If the oil disappears before the fuel is used up, insufficient lubrication can result. Therefore, it is necessary to avoid running out of oil before fuel.

Utility model content

This invention was made after recognizing the above situation, and it aims at providing the oil pump and the portable work machine which can accurately determine the maximum value of the discharge quantity of the engine oil per 1 stroke.

One mode of the utility model is an oil pump. The oil pump has:

a pump casing formed with an inlet and an outlet;

a pump gear shaft that rotates within said pump casing via a gear system;

a first preload unit, which preloads the pump gear axially to one end opening of the pump casing; and

a locking part, which locks the pump gear shaft at the opening at the one end of the pump casing,

In this oil pump, the pump gear shaft is reciprocated in the axial direction in the pump casing to supply oil, wherein

The end surface of the pump gear shaft on the locking part side has an inclined surface,

The locking part has: a cover part, which is provided at the opening of the one end of the pump casing, and the cover part corresponds to the rotation position of the pump gear shaft, and is positioned at a position from the central axis of the pump gear shaft to Engage with the inclined surface of the pump gear shaft at the separated position to lock the pump gear shaft; and an adjustment shaft, which is arranged to be substantially coaxial with the pump gear shaft, passes through the cover, The adjustment shaft engages with the end of the pump gear shaft corresponding to the rotational position of the pump gear shaft to lock the pump gear shaft,

If the adjustment shaft is rotated relative to the cover, the axial position of the adjustment shaft changes, and the rotatable range of the adjustment shaft relative to the cover is limited to a predetermined angle range, regardless of the At any rotational position within the rotatable range, the adjustment shaft defines one end of the range of travel of the pump gear shaft.

It may be configured such that a second pretensioning unit is provided, and the second pretensioning unit pretensions the adjustment shaft in the axial direction relative to the cover portion, and the cover portion has an inclined portion relative to the inclined portion. The plane perpendicular to the axis of the adjustment shaft is inclined, and the anti-falling part engaged with the inclined part is provided on the adjustment shaft. When the adjustment shaft is rotated relative to the cover part, the anti-off part Sliding on the inclined portion, the axial position of the adjusting shaft changes.

It may be configured such that wall portions are provided at both ends of the inclined portion, and the rotation range of the adjustment shaft is limited by the abutment of the anti-slip portion on the wall portions.

A pin may be provided which penetrates the pump casing so as to be non-parallel to the axial direction of the pump gear shaft, and a groove through which the pin passes is provided in the cover so that the pin prevents The cover part is detached from the pump casing.

The pin may function as a rotation stop that prevents the cover from rotating relative to the pump housing.

The pin may become a positioning component for the pump housing relative to the main body of the working machine.

Another aspect of the present utility model is a portable work machine equipped with the oil pump.

In addition, an embodiment obtained by converting the present invention between arbitrary combinations of the above constituent elements, methods, systems, etc. is also effective as an embodiment of the present invention.

The effect of utility model

According to the present invention, it is possible to provide an oil pump and a portable work machine capable of accurately specifying the maximum value of the oil discharge amount per one stroke.

Description of drawings

FIG. 1 is a side view of the portable work machine according to the embodiment of the present invention.

Fig. 2 is an enlarged side view of main parts in which a part of the portable work machine is cut away.

Fig. 3(A) is an enlarged sectional view of the oil pump 6 shown in Fig. 2, Fig. 3(B) is a B-B sectional view of Fig. 3(A), and Fig. 3(C) is a C-C sectional view of Fig. 3(A).

Fig. 4 is an enlarged view of an essential part of Fig. 3(A) .

Fig. 5 is an enlarged view of the main part of Fig. 3(B) (when the stroke is the shortest).

Fig. 6 is an enlarged view of the main part of Fig. 3(B) (when the stroke is the longest).

FIG. 7 is an explanatory view of the operation when the pump gear shaft 10 is rotated in FIG. 3(A) .

Explanation of labels

1 Main Body, 2 Guide Rod, 2a Discharge Hole, 3 Saw Chain, 4 Oil Tank, 5 Oil, 6 Oil Pump, 7 Suction Passage, 8 Discharge Passage, 8a Discharge Port, 9 Pump Housing, 9a Inlet, 9b Outlet, 9c Opening, 10 Pump gear shaft, 10a Inclined surface, 10b Flat surface, 10c Center shaft end surface, 10d Gear part (worm wheel), 10e Notched part, 11 First spring, 12 Cover part, 12a Inclined part, 12b Wall part , 12c convex part, 12d groove part, 13 second spring, 14 anti-drop pin, 15 adjustment shaft, 15a end surface, 15b engaging part, 16 positioning pin, 16a engaging part, 17 handle, 18 throttle rod, 19 inside Space, 20 gears (worm), 21 positioning pins

Detailed ways

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Here, the same or equivalent structural elements, components, and the like shown in the drawings are assigned the same reference numerals, and redundant descriptions are appropriately omitted. In addition, the embodiment does not limit the present invention, but is only an example, and all the features and combinations described in the embodiment are not necessarily the essential content of the invention.

FIG. 1 is a side view of the portable work machine according to the embodiment of the present invention. Fig. 2 is a side view of main parts in which a part of the portable working machine is cut away.

The portable work machine of this embodiment is a chain saw, and a drive source such as a motor (not shown) is provided inside the main body 1 . The guide rod 12 extends in front of the main body 1 , and the saw chain 3 is provided around the guide rod 2 . A handle 17 is connected to the main body 1, and a throttle rod 18 is arranged on the handle 17. The user adjusts the pulling amount of the throttle lever 18 , thereby adjusting the rotational speed of the drive source from an idle state to a full speed state. When the rotational speed of the driving source is greater than or equal to a constant amount, the saw chain 3 that guides the outer periphery of the rod 2 starts to move, and cutting operations such as trees can be performed.

As shown in FIG. 2 , an oil tank 4 is provided in the main body 1 , and engine oil 5 (lubricating oil) is stored in the oil tank 4 . The oil 5 is sucked up by the oil pump 6 through the suction passage 7 , and discharged from the discharge port 8 a through the discharge passage 8 . The discharged engine oil 5 is sprayed from the discharge hole 2a provided on the guide rod 2, and adheres to the saw chain 3, reducing the friction between the guide rod 2 and the saw chain 3, and between the saw chain 3 and the material to be cut. , to prevent scorching of the saw chain 3.

FIG. 3(A) is an enlarged sectional view of the oil pump 6 shown in FIG. 2 . Fig. 3(B) is a B-B sectional view of Fig. 3(A). Fig. 3(C) is a C-C sectional view of Fig. 3(A). Fig. 4 is an enlarged view of an essential part of Fig. 3(A) . Fig. 5 is an enlarged view of the main part of Fig. 3(B) (when the stroke is the shortest). Fig. 6 is an enlarged view of the main part of Fig. 3(B) (when the stroke is the longest).

The oil pump 6 includes a pump housing 9 , a pump gear shaft 10 (plunger), a first spring 11 as a first pretensioner, a cover 12 , a second spring 13 as a second pretensioner, and an adjustment shaft 15 . The pump casing 9 is, for example, bottomed cylindrical metal, and is fixed at a predetermined position inside the main body 1 . The pump casing 9 has an inflow port 9a and an outflow port 9b on the outer peripheral surface. The inflow port 9 a is connected to the suction passage 7 , and the outflow port 9 b is connected to the discharge passage 8 . The pump housing 9 and the pump gear shaft 10 form an internal space 19 capable of communicating with the inflow port 9 a and the outflow port 9 b. The oil pump 6 sucks the oil 5 into the internal space 19 from the suction passage 7 through the inlet 9 a through the reciprocating operation of the pump gear shaft 10 in the pump housing 9 , and discharges the oil 5 from the internal space 19 to the discharge passage 8 through the outlet.

The pump gear shaft 10 is rotatably arranged in the pump casing 9 . The first spring 11 is provided between the pump casing 9 and the pump gear shaft 10, and pretensions the pump gear shaft 10 toward one end opening of the pump casing 9 (upward in FIG. 3(A) ). The cover portion 12 is provided at the one-end opening of the pump casing 9 , and locks the pump gear shaft 10 according to the rotational position of the pump gear shaft 10 as will be described later. The adjustment shaft 15 is provided substantially coaxially with the pump gear shaft 10 , penetrates the cover portion 12 , and locks the pump gear shaft 10 according to the rotational position of the pump gear shaft 10 as will be described later. In other words, the pump gear shaft 10 is locked on the cover portion 12 or the adjustment shaft 15 corresponding to its own rotational position. The second spring 13 is provided between the cover portion 12 and the adjustment shaft 15, and biases the adjustment shaft 15 in a direction away from the pump gear shaft 10 (upward in FIG. 3(A) ). The outer peripheral surface of the adjusting shaft 15 is fixed (integrated) by means of press fitting or the like, and the anti-loosening pin 14 is engaged (hooked) on the inclined portion 12a described later of the cover portion 12, thereby preventing the adjusting shaft 15 from falling out. Comes off from the cover 12. Moreover, the upper end part of the adjustment shaft 15 is provided with the engaging part 15b which is the operation part which can engage with a hand tool. The pump gear shaft 10 and the adjustment shaft 15 are arranged so that the rotation shaft faces vertically with respect to the main body 1 . rotation, whereby the adjustment shaft 15 can be adjusted to any desired rotational position.

The pump gear shaft 10 has an inclined surface 10a, a flat surface 10b, and a center shaft end surface 10c on the end surface on the cover portion 12 side. The inclined surface 10 a is inclined in a direction around the axis of the pump gear shaft 10 with respect to a plane perpendicular to the axis of the pump gear shaft 10 . The flat surface 10 b is parallel to a plane perpendicular to the axis of the pump gear shaft 10 . The inclined surfaces 10 a and the flat surfaces 10 b are alternately provided at two places along the direction around the axis of the pump gear shaft 10 . A center shaft end surface 10c is provided in a region surrounded by the inclined surface 10a and the flat surface 10b. The central shaft end face 10c is parallel to a plane perpendicular to the axis of the pump gear 10.

The pump gear shaft 10 has a gear portion 10d (worm wheel) on the outer peripheral portion. Through an opening 9c provided on the outer peripheral surface of the pump casing 9, the gear portion 10d meshes with a gear 20 (worm) driven to rotate by the drive source. The pump gear shaft 10 rotates within the pump casing 9 in conjunction with the rotation of the drive source by the meshing of the gear portion 10 d and the gear 20 . A notch 10 e is provided on the outer peripheral surface of the lower end portion of the pump gear shaft 10 . The notched portion 10e is formed to communicate with the inlet 9a or the outlet 9b of the pump housing 9, or not to communicate with the inlet 9a or the outlet 9b according to the rotational position of the pump gear shaft 10 (internal space 19 closed state).

The cover portion 12 has an inclined portion 12 a inclined with respect to a plane perpendicular to the axis of the adjustment shaft 15 . The inclined portion 12a is provided toward the pump gear shaft 10 side (lower side in FIG. 3(B) ). Wall portions 12b extending in the axial direction of the adjustment shaft 15 are respectively provided at both ends of the inclined portion 12a. In other words, the cover portion 12 has a concave portion (notch) on the pump gear shaft 10 side, and the concave portion has the inclined portion 12 a as a bottom surface and the wall portion 12 b as a side wall.

The fall prevention pin 14 provided on the adjustment shaft 15 is engaged with the inclined portion 12 a, thereby preventing the adjustment shaft 15 biased by the second spring 13 from falling off from the cover portion 12 . When the adjusting shaft 15 is rotated with respect to the cover part 12, the anti-dropping pin 14 slides (up and down) on the inclined part 12a, and the axial position of the adjusting shaft 15 changes (FIGS. 5 and 6). The rotatable range of the adjustment shaft 15 with respect to the cover 12 is limited due to the abutment of the anti-dropping pin 14 against the wall 12b. The end surface 15 a of the adjustment shaft 15 on the pump gear shaft 10 side engages with the center shaft end surface 10 c of the pump gear shaft 10 , whereby the adjustment shaft 15 locks the pump gear shaft 10 . The stroke length of the pump gear shaft 10 can be adjusted by rotating the adjustment shaft 15 to change the axial position of the adjustment shaft 15 .

FIG. 5 shows the state in which the stroke of the pump gear shaft 10 is the shortest, and FIG. 6 shows the state in which the stroke is the longest. The longest stroke X1 shown in FIG. 6 is Y longer than the shortest stroke X shown in FIG. 5 . The difference Y is the adjustable range of the stroke of the pump gear shaft 10 realized by the rotation of the adjustment shaft 15, and is determined by the height difference of the inclined portion 12a. In FIGS. 5 , 6 and any state therebetween (ie, at any rotational position within the rotatable range of the adjustment shaft 15 ), the adjustment shaft 15 defines one end of the travel range of the pump gear shaft 10 .

The cover portion 12 has a boss portion 12c that protrudes toward the pump gear shaft 10 side. Viewed in the axial direction of the pump gear shaft 10 , the distances from the central axis of the pump gear shaft 10 to the inclined surface 10 a and the flat surface 10 b are equal from the protrusion 12 c. The cover part 12 locks the pump gear shaft 10 by engaging the protrusion part 12c with the inclined surface 10a or the flat part 10b. The pump gear shaft 10 is locked to one of the cover portion 12 and the adjustment shaft 15 depending on the rotational position of the pump gear shaft 10 .

As shown in FIG.3(A) and FIG.4, the cover part 12 has the groove part 12d in the outer peripheral surface. The groove portion 12d extends perpendicularly to the rotation axis of the pump gear shaft 10 . The positioning pin 16 , which penetrates the pump casing 9 perpendicular to the rotation axis of the pump gear shaft 10 , passes through the groove portion 12 d. The engagement between the groove portion 12 d and the positioning pin 16 prevents the lid portion 12 from coming off the pump casing 9 and the rotation of the lid portion 12 relative to the pump casing 9 . In addition, the positioning pin 16 also functions as a positioning member for the pump casing 9 with respect to the main body 1 . That is, the positioning pin 16 protrudes to one side (upper side in FIG. 3(C) and rear side in the drawing in the perspective of FIG. 2 and FIG. 3(A) ) with respect to the pump housing 9 to form an engaging portion 16a. The locating pin 16 and the locating pin 21 (having the same engaging portion as the locating pin 16 ) provided on the other end side in the longitudinal direction of the pump housing 9 are engaged with an unillustrated engaging portion on the main body side, thereby locking the casing. The body 9 is positioned relative to the main body 1 .

FIG. 7 is an explanatory view of the operation when the pump gear shaft 10 is rotated in FIG. 3(A) .

7(A) is the state where the pump gear shaft 10 is located at the bottom (after the internal space 19 is shrunk), and the raised portion 12c of the cover 12 engages (contacts) with the flat surface 10b at a higher position of the pump gear shaft 10. ), the end surface 15a of the adjustment shaft 15 is opposite to the central shaft end surface 10c of the pump gear shaft 10 in a non-contact manner, and the notch 10e of the pump gear shaft 10 is not connected to the inlet 9a and the outlet 9b of the pump casing 9 (inner space 19 is closed). In addition, before and after the state shown in FIG. 7(A), and during the period when the notch 10e and the inlet 9a and the outlet 9b of the pump casing 9 are not in communication, the protrusion 12c of the cover 12 and the pump gear Since the flat surface 10b of the shaft 10 is engaged, the pump gear shaft 10 does not move in the axial direction. Accordingly, when the internal space 19 is closed, mechanical loads on the pump casing 9 and the pump gear shaft 10 due to the change in the size of the internal space 19 are prevented.

Fig. 7(B) is the state after the pump gear shaft 10 is rotated 90° from the state shown in Fig. 7(A), the convex part 12c of the cover part 12 and the center of an inclined surface 10a of the pump gear shaft 10 in the axial direction The end surface 15a of the adjustment shaft 15 is opposed to the central shaft end surface 10c of the pump gear shaft 10 in a non-contact manner, and the cutout portion 10e of the pump gear shaft 10 communicates with the inlet 9a of the pump casing 9 . In the process of reaching the state of FIG. 7(B) from the state of FIG.

Fig. 7 (C) is the state after the pump gear shaft 10 is further rotated 90° from the state shown in Fig. 7 (B). The end surface 15a of the pump gear shaft 10 engages (contacts) the end surface 15a of the center shaft portion of the pump gear shaft 10, and the raised portion 12c of the cover portion 12 faces the lower flat surface 10b of the pump gear shaft 10 in a non-contact manner. The notched portion 10e of the pump gear shaft 10 does not communicate with either the inlet 9a or the outlet 9b of the pump casing 9 (the internal space 19 is closed). In the process from the state of FIG. 7(B) to the state of FIG. 7(C), the pump gear shaft 10 is raised by the remaining stroke amount, and the oil 5 is further sucked into the internal space 19 . In addition, before and after the state shown in FIG. 7(C), and during the period when the notch 10e is not in communication with the inlet 9a and the outlet 9b of the pump casing 9, the end surface 15a of the adjustment shaft 15 is in contact with the pump gear shaft 10. Therefore, the pump gear shaft 10 does not move in the axial direction. Accordingly, when the internal space 19 is closed, mechanical loads are prevented from being applied to the pump housing 9 and the pump gear shaft 10 due to the size change of the internal space 19 .

Fig. 7 (D) is the state after the pump gear shaft 10 is further rotated 90° from the state shown in Fig. 7 (C). The central part of the pump gear shaft 10 engages (contacts) with the end surface 15a of the adjustment shaft 15 in a non-contact manner with the central shaft end surface 10c of the pump gear shaft 10, and the notched part 10e of the pump gear shaft 10 meets the outlet of the pump casing 9. 9b is connected. In the process of reaching the state of Fig. 7 (D) from the state of Fig. 7 (C), the pump gear shaft 10 descends a specified distance (with the process of reaching the state of Fig. 7 (C) from the state of Fig. 7 (B) same as the ascent distance), the engine oil 5 is discharged from the internal space 19. Then, in the process of reaching the state of FIG. 7(A) from the state of FIG.

In addition, in the state of FIG. 7(B) and FIG. 7(D), depending on the axial position of the adjustment shaft 15, sometimes the end face 15a of the adjustment shaft 15 is engaged with the end face 10c of the central shaft portion of the pump gear shaft 10 ( abutment), the convex portion 12c of the cover portion 12 is not in contact with the inclined surface 10a of the pump gear shaft 10 . In this case, in the process of reaching the state of FIG. 7(C) from the state of FIG. 7(B) and the process of reaching the state of FIG. 7(D) from the state of FIG. 7(C), the pump gear shaft 10 Without moving in the axial direction, the engine oil 5 is neither sucked into the internal space 19 nor discharged from the internal space 19 .

According to the present embodiment, the following effects can be achieved.

(1) By limiting the rotatable range of the adjustment shaft 15 relative to the cover portion 12, regardless of any rotational position within the rotatable range, one end of the stroke range of the pump gear shaft 10 by the adjustment shaft 15 can be used Make provisions. Accordingly, the longest stroke of the pump gear shaft 10 can be accurately determined, and furthermore, the upper limit of the discharge amount of the engine oil 5 can be accurately determined for each reciprocation process (per one stroke) of the pump gear shaft 10 . Therefore, it is possible to prevent the engine oil 5 from being used up before the fuel, and to reduce the risk of insufficient lubrication.

(2) When adjusting the discharge amount of the engine oil 5, it is not necessary to shift the phase of the reciprocating movement of the pump gear shaft 10 relative to the timing at which the notch 10e communicates with the inlet 9a or the outlet 9b of the pump housing 9, Therefore, the cover part 12 can be fixed to the pump casing 9, the cover part 12 is hard to fall off from the pump casing 9, and it can prevent that the lifetime of a component falls.

(3) It is configured such that the adjustment shaft 15 is prevented from coming off from the cover portion 12 and the stroke of the adjustment shaft 15 is adjusted by engaging the inclined portion 12 a of the cover portion 12 with the drop-off prevention pin 14 provided on the adjustment shaft 15 . Therefore, compared with the structure (screw type) in which the cover portion 12 and the adjustment shaft 15 are screwed together, it is possible to perform stroke adjustment with high precision.

Above, the present invention has been described by taking the embodiment as an example, but those skilled in the art should understand that various modifications can be made within the scope described in the claims for each structural element and each processing program in the embodiment. Hereinafter, modification examples will be described.

The portable working machine is not limited to the chain saw illustrated in the embodiment, and may be other portable working machines such as pole saws.

Claims (7)

1. An oil pump, which has: a pump casing formed with an inlet and an outlet; a pump gear shaft that rotates within said pump casing via a gear system; a first preload unit, which preloads the pump gear axially to one end opening of the pump casing; and a locking part that locks the pump gear shaft at the opening side of the one end of the pump casing, In this oil pump, the pump gear shaft is reciprocated in the axial direction in the pump casing to supply oil, wherein The end surface of the pump gear shaft on the locking part side has an inclined surface, The locking part has: a cover part, which is provided at the opening of the one end of the pump casing, and the cover part corresponds to the rotation position of the pump gear shaft, and is positioned at a position from the central axis of the pump gear shaft to Engage with the inclined surface of the pump gear shaft at the separated position to lock the pump gear shaft; and an adjustment shaft, which is arranged to be substantially coaxial with the pump gear shaft, passes through the cover, The adjustment shaft engages with the end of the pump gear shaft corresponding to the rotational position of the pump gear shaft to lock the pump gear shaft, If the adjustment shaft is rotated relative to the cover, the axial position of the adjustment shaft changes, and the rotatable range of the adjustment shaft relative to the cover is limited to a predetermined angle range, regardless of the At any rotational position of the rotatable range, the adjustment shaft defines one end of the range of travel of the pump gear shaft. 2. The oil pump according to claim 1, wherein: A second pretensioning unit is provided, and the second pretensioning unit pretensions the adjustment shaft relative to the cover part in the axial direction, and the cover part has an inclined part relative to the adjustment shaft. The plane perpendicular to the axis of the shaft is inclined, and the anti-off part engaged with the inclined part is provided on the adjustment shaft. If the adjustment shaft is rotated relative to the cover part, the anti-off part will sliding on the part, the axial position of the adjustment shaft changes. 3. The oil pump according to claim 2, wherein: Wall parts are provided at both ends of the inclined part, and the rotatable range of the adjustment shaft is limited by the abutment of the anti-off part against the wall parts. 4. The oil pump according to claim 1, wherein: A pin is provided, and the pin penetrates the pump casing so as not to be parallel to the axial direction of the pump gear shaft, and a groove portion through which the pin passes is provided on the cover, and the pin prevents the cover from detach from the pump casing. 5. The oil pump according to claim 4, wherein: The pin functions as a stopper that prevents the cover from rotating relative to the pump casing. 6. The oil pump according to claim 4, wherein: The pin serves as a positioning member for the pump housing relative to the main body of the working machine. A portable work machine comprising the oil pump according to any one of claims 1 to 6.