JPS63263285A - Oil pump - Google Patents

Abstract

PURPOSE:To ensure returning path for leaked oil reliably by casting a pipe when pump body is casted. CONSTITUTION:When a front body 2 is manufactured, a core for forming a hole 2a is partially inflated then one end 42a of a pipe 42 is assembled therein while the other end 42b is assembled in a core print so as to position the pipe 42, thereafter the front body 2 is casted. When such front body 2 is assembled, one end 42a of the pipe 42 opens into a space 42a while the other end 42b communicates with a suction port 30 of a rear body 4 so as to enable circulation of inner leak oil around an input shaft 10. Consequently, necessary oil return path area can be ensured, and complex machining or blank plug is not required, resulting in cost reduction.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an oil pump.

(Prior Art) Generally speaking, an oil pump has a cam ring and a rotor that rotates within the cam ring housed in a pump body, and the rotor is connected to the tip of an input shaft inserted into the pump body. It transmits rotation to the rotor. In this type of oil pump, oil leaking inside the oil pump is used to lubricate the bearing that rotatably supports the input shaft relative to the pump body and the oil seal that prevents oil from leaking to the outside. That's what I do.

This oil is then returned to the suction side of the pump through a return passage that communicates the space around the human power shaft with a low pressure section such as a suction passage (Japanese Utility Model Publication No. 58-40592).

Conventionally, such a return passage is formed by machining. In other words, due to the shape of the pump body or internal passages, it is difficult to connect the space around the input shaft with the low pressure section in a straight line, so machining from multiple directions is performed to connect them internally. It was necessary to form a return passage by connecting.

[Problem that the invention seeks to solve]

As mentioned above, in conventional oil pumps, the return passage is formed by complicated machining, so sometimes the passages do not connect internally due to machining errors, or the connecting part is narrow due to misalignment, making it impossible to secure a sufficient area. There was a case. If the passages are not connected, there is no place for leaked oil to escape, resulting in high pressure, which can lead to external leakage due to damage to the oil seal.Also, if the passages are incompletely connected, there is no place for leaked oil to escape, resulting in external leakage. When the amount of leakage is large, the pressure of the leaked oil increases, causing the lip of the oil seal to wear out and affecting durability.

The present invention has been made to eliminate such drawbacks.
To provide an oil pump that can reliably secure a return path for leaked oil.

(Means for Solving the Problems) The oil pump according to the present invention lubricates the bearing that supports the manual shaft within the pump body and the oil seal fitted to the input shaft with internal leakage oil, and then The return passage for refluxing the pump body to the low-pressure section is constructed from a pipe cast into the pump body when the pump body is cast.

(Function) In the oil pump according to the present invention, there is no need to internally connect a plurality of passages formed by machining as in the past, and the area of the passage can be reliably secured regardless of the shape of the passage.

〔Example〕

The present invention will be explained below with reference to illustrated embodiments. FIG. 3 is a longitudinal cross-sectional view showing an example of an oil pump, in which a pump cartridge is installed in a pump body (6) made up of a cylindrical front body (2) and a cup-shaped rear body (4). (8) is accommodated. In addition, in this figure,
A return passage formed in the front body (2) for circulating leaked oil to the low pressure side is omitted.

Hole (2a) with multiple steps in front body (2)
A human power shaft (lO) is inserted inside, and a needle bearing (
12) and a ball bearing (14). Both of these bearings (12),
An oil seal (16) is provided between (14) to prevent oil leakage to the outside. Human power axis (lO)
A rotor (18) is connected to the end portion (10a) of the pump body (6) by a spline and is driven to rotate. Radial slits are formed in the rotor (bond 8) at equal intervals in the circumferential direction, and vanes (20) are fitted into each of these slits so as to be movable forward and backward.

A cam ring (22) having a substantially elliptical cam surface on the inner periphery is arranged on the outer circumferential side of the rotor (18), and the vane (20) slides on the inner surface of this cam ring (22).

The rotor (18) and cam ring (22) are connected to a side plate (24) on the front body (2) side and a pressure plate (24) placed on the bottom side of the rear body (4).
6) and the pressure plate (26).
, the cam ring (22) and the side plate (24) are positioned in the rotational direction with respect to the front body (2) by a pin (28).

The rear body j' (4) has a suction port (30) connected to an oil tank (not shown) and an upstream suction passage (32).
A downstream suction passage (34) connected to this upstream suction passage (32) is formed in the front body (2). The rotor (
18) is rotated, the two plates (24), (
2B), the volume inside each pump chamber formed by the vane (20) rotating while in contact with the cam ring (22) increases or decreases, and the volume of air sucked into this pump chamber from the suction passages (32), (34). The oil is on the pressure plate (
It is discharged into the discharge chamber (36) at the bottom of the rear body (4) through the discharge port (26a) of 26), and further, the flow rate is controlled by the flow control valve (38) and sent to the hydraulic equipment.

Internal leakage oil during pump operation travels around the input shaft (10), passes through the needle bearing (12), and enters the space (40) between this bearing (12) and the oil seal (16). , lubricate the bearing (12) and the oil seal (16). Thereafter, this oil is sucked back into the suction port (30) on the low pressure side.

1 and 2 show the front body (2) of the oil pump alone. This front body (
2), one end (42a) protrudes into a recess (40a) that slightly bulges the space (40) between the twenty dollar bearing (12) and the oil seal (16);
The other end (42b) is the joint surface (2b) with the rear body (4)
A single pipe (42) protruding from the side is embedded. This pipe (42) is partially exposed within the suction passage (34) formed in the front body (2) to the extent that it does not obstruct the flow of oil in this passage (34). When the front body (2) having such a shape is assembled as shown in Fig. 3, one end (42a) of the pipe (42) opens into the space (40), and the other end (42b) opens into the rear body (42).
It communicates with the suction port (30) of 4), so that internal leakage oil around the human power shaft (10) can be refluxed.

When manufacturing the above front body (2), the holes (2)
The pipe (42) is formed by inflating a part of the core to form the pipe (42), and incorporating one end (42a) of the pipe (42) into this part and incorporating the other end (42b) into the baseboard.
) and perform casting. This makes it possible to always secure the passage area necessary for the return passage, and also eliminates the need for complicated machining and driving of blind plugs as in the past, resulting in the effect of reducing costs. The reason why the pipe (42) is partially exposed inside the suction passage (34) is to ensure reliable positioning by holding the pipe (42) in the core that forms this passage (34). It does not necessarily need to be exposed inside the passageway (34).

(Effects of the Invention) As described above, according to the present invention, by ensuring the area of the return passage, the durability of the oil seal can be significantly improved, and costs can also be reduced.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view of a front body constituting an oil pump according to an embodiment of the present invention, Fig. 2 is a front view of the front body shown in Fig. 1, and Fig. 3 is a longitudinal sectional view of the oil pump. be. (2) --- Front body (10) that makes up the pump body --- Human power shaft (12) --- Bearing (16) --- Oil seal (42) --- Pipe (return passage) Fig. 1 Figure 2 Cause 3 16: Ill seal

Claims (1)

[Claims] The bearing that supports the input shaft within the pump body and the oil seal fitted to the input shaft are lubricated by internal leakage oil, and this oil is returned to the low pressure section via the return passage formed in the pump body. An oil pump characterized in that the return passage is constituted by a pipe cast into the pump body when the pump body is cast.