JP2534569Y2 - General-purpose engine oil pump - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal structure applied to an oil pump of a general-purpose engine.

[0002]

2. Description of the Related Art A conventional general-purpose engine oil pump will be described with reference to FIG. FIG. 3 is a cross-sectional view of an oil pump mounted on a conventional general-purpose engine. In the figure, reference numeral 4 denotes a drive shaft, which is a pump shaft. 5 is a balancer shaft and a drive shaft 4 at the shaft end.
Are connected. A ball bearing 12 supports the end of the balancer shaft 5, and the drive shaft 4 is located outside the balancer shaft 5. Reference numeral 2 denotes an oil pump which is mounted on the drive shaft 4. Reference numeral 24 denotes a pump case in which the oil pump 2 is incorporated and forms a bearing box for the ball bearing 12. Reference numeral 21 denotes a side cover which is attached to a crank chamber (not shown). 22 is a peripheral wall and side cover 2
1 and a pump case 24 is fitted inside.

[0003] Reference numeral 25 designates bolts for connecting the pump case 24 to the side cover 2.
It is tightened to 1. Numeral 23 denotes a space surrounded by the peripheral wall 22 and accommodates the pump case 24 therein. 10
Is an oil inlet provided in the pump case 24 at a suction port. Reference numeral 9 denotes an oil passage which is provided in the pump case 24 and has an inlet 10
Leads to. A discharge port 11 is provided in the pump case 24 and is a discharge port for oil. Reference numeral 26 denotes a rotor cover which is attached to the pump case 24. 27 is a bolt for attaching the rotor cover 26 to the pump case 24. Side cover 2
1 or the pump case 24 is provided with an oil return hole for returning oil to an oil pan (not shown).

The operation of the conventional example will be described. The rotation of the balancer shaft 5 is transmitted to the drive shaft 4 so that the pump 2 rotates and the oil passage 9
Then, the oil is sucked from the suction port 10 and discharged to the discharge port 11. The remainder is drained from the oil return hole to the oil pan.

[0005]

When the discharge-side oil passage is formed, the balancer shaft cannot be used in the conventional example shown in FIG. A discharge oil passage is formed by using a camshaft in Japanese Utility Model Publication No. 63-41527, but in this case, the bearing of the camshaft needs to be a sliding bearing in order to secure an oil seal. Lack. This is particularly problematic for vertical engines where the bearings are not in the oil bath. Provided with a discharge-side oil passage in the drive shaft and a ball bearing as a bearing to further improve the reliability of the bearing. Suitable as a means to prevent oil leakage and send oil to the rotating drive shaft while securing hydraulic pressure. There is nothing cheap. In the conventional example shown in FIG. 3, the components of the oil pump are complicated and bolts are fastened at various places, which is disadvantageous in terms of assembly cost.

It is an object of the present invention to provide an oil pump for a general-purpose engine which solves the above-mentioned problems and which can use a drive shaft supported by a ball bearing for a discharge oil passage and has a simple structure.

[0007]

In a general-purpose engine having one end of a balancer shaft supported on a side wall via a ball bearing, a suction port and a discharge port are integrally formed on the side of the side wall on the shaft end side of the balancer shaft. The pump casing provided, an oil pump incorporated in the pump casing, and functions as a pump end face cover between one end face of the oil pump and the ball bearing to seal both oils, and to the discharge portion. A cover having an oil passage for guiding the discharged oil to an oil passage provided on the balancer shaft.

[0008]

[Function] The cover holds the oil pump on one end face of the oil pump and the oil pump, and at the same time, has a minimum gap between the outer periphery of the balancer shaft to prevent oil leakage and discharge oil in the balancer shaft. Rolling bearings can be used that can have a seal that can be guided to the road. The cover secures the required gap in the axial direction of the oil pump and regulates the dimensions up to the axial end surface of the ball bearing. By assembling the pump, cover and bearing in order, the axial clearance of the balancer shaft is maintained. Is determined.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of an embodiment according to the present invention, and FIG. 2 is a plan view of a pump casing 53 taken along the arrow II in FIG.
In the figure, reference numeral 58 denotes a known part of the engine, which is a crankcase. Reference numeral 59 denotes a ball bearing provided in the crank chamber 58. 51 is a side wall attached to the crank chamber 58. Numeral 60 denotes a ball bearing provided on the side wall 51. 57 is a balancer shaft and ball bearings 59 and 6
0 and is connected to a crankshaft (not shown) by a gear. 53 is a pump casing, 54 is a suction port, and 55 is a discharge port, both of which are formed on the side wall 51. Reference numeral 52 denotes an oil pump, which is incorporated in a pump casing 54. 57a is a groove provided on the end face of the balancer shaft 57. 57b is a discharge oil passage formed in the center of the balancer shaft 57 from the lower surface. An oil outlet 57c is a hole penetrating the balancer shaft 57 perpendicularly to the axis, and also penetrates the discharge oil passage 57b. Reference numeral 61 denotes a pump shaft on which the oil pump 52 is mounted, and one end of which is fitted in the groove 57a.

Reference numeral 56 denotes a cover between the oil pump 52 and the ball bearing 60 for closing the end face of the oil pump 52 and covering the lower side of the ball bearing 60. 56
a is an oil passage provided on the cover 56. An oil passage 55a is provided in the pump casing 54 and communicates the discharge port 55 with the oil passage 56a. 62 is an oil passage which is an inlet 54
And an oil reservoir (not shown). Numeral 63 denotes a seal portion which is a clearance between the balancer shaft 57 and the cover 56 and is set to an appropriate clearance necessary for the balancer shaft 57 to rotate smoothly and to minimize oil leakage.

The operation of the embodiment will be described. When the balancer shaft 57 is rotated by a gear system (not shown), rotation is transmitted to the pump shaft 61 by the groove 57, and the oil pump 52 rotates to suck oil from the suction port 54 through the oil passage 62 and discharge the oil to the discharge port 55. . The oil passage 55a guides the oil discharged to the discharge port 55 to the oil passage 56a. The oil reaches the end of the balancer shaft 57 and the seal portion 63 of the cover 56, and the seal portion 63 smoothly rotates the balancer shaft 57 and secures hydraulic pressure by minimizing oil leakage. The oil kept at the pressure reaches the oil passage 57b and the oil injection hole 57c, and can perform a predetermined lubrication function. Even if the gap of the seal portion 63 of the cover 56 becomes smaller than an appropriate value due to variation, this portion is forcibly lubricated by the oil discharged from the oil pump 52 and can function as a normal sliding bearing without any problem. As described above, the cover 56 forms the discharge oil passage, and at the same time, has an oil seal with the balancer roller 57, and further regulates the gap in the axial direction of the oil pump 52 so as to control the dimension when the ball bearing 60 is press-fitted. It has a function of regulating the axial gap to an appropriate value.

[0012]

The bearing of the balancer shaft, which is the drive shaft of the pump, is a ball bearing, and the oil discharged from the pump can be introduced coaxially, thereby increasing the reliability of the bearing. The oil passage can be installed in the balancer shaft, and the rotary jet port 57c can be set at a required position without using a dedicated oil pipe part. The cover having the oil pump, the cover, the press-fitting positioning of the ball bearing, and the discharge oil supply passage makes the structure simple and easy to assemble, and does not require bolt fastening, thereby reducing the cost. Therefore, this invention can provide an oil pump for a general-purpose engine in which a drive shaft supported by a ball bearing can be used for a discharge oil passage and whose structure is simple.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment according to the present invention.

FIG. 2 is a view taken along a line II in FIG.
Top view of

FIG. 3 is a sectional view of a conventional oil pump.

[Explanation of symbols]

 51 side wall 52 oil pump 53 pump casing 54 suction port 55 discharge port 56 cover 56a oil passage 57 balancer shaft 57a discharge oil passage

Claims (1)

(57) [Scope of request for utility model registration] In a general-purpose engine in which one end of a balancer shaft (57) is supported on a side wall (51) via a ball bearing (60), a shaft end face side of the balancer shaft (57) of the side wall (51). A pump casing (53) provided with a suction port (54) and a discharge port (55) in one body;
An oil pump (52) incorporated in the pump casing (53), and between the oil pump and the ball bearing (60), functioning as an end face cover of the oil pump, performing oil sealing of both oil pumps and the discharge port; Department (5
And a cover (56) having an oil passage (56a) for guiding the oil discharged to the balancer shaft (57) to the discharge oil passage (57b) provided on the balancer shaft (57). Oil pump.