CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and benefits of Chinese Patent Application Serial No. 201120472248.X, filed with the State Intellectual Performance Office (SIPO) of P. R. China on November 24, 2011, the entire contents of which are incorporated herein by reference.

FIELD

The present disclosure relates to an oil pump, an engine comprising the oil pump and a vehicle comprising the engine.

BACKGROUND

The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.

Conventionally, an oil pump in an engine of a vehicle is usually a rotor pump. The rotor pump normally may comprise an inner rotor, an outer rotor, a pump case and a pump cover. The inner and outer rotors are disposed eccentrically within the pump case. The pump case and the pump cover are fixed by, for example, fastening screws. A low pressure oil chamber communicated with an oil inlet and a high pressure oil chamber communicated with an oil outlet may be formed in the pump case. When the engine is running, the engine drives the inner rotor to rotate, and the outer rotor may rotate along with the inner rotor. With the rotation of the inner rotor and the outer rotor, the low pressure oil from the oil inlet is gradually pressurized and becomes high pressure oil which is, subsequently released from the oil outlet.

Generally, the oil pump has a pressure relief device to release the exceeding high pressure oil to the oil sink of the engine when the pressure of the high pressure oil chamber exceeds a preset limit. Therefore, the pressure relief device may prevent overpressure of the oil pressure in the engine, however on the other hand, may cause loss of energy and affect the efficiency of oil pumping. SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In viewing thereof, the present disclosure is directed to solve at least one of the problems existing in the art. Accordingly, an oil pump may need to be provided, which may improve the efficiency of oil pumping and reduce the loss of energy.

According to an aspect of the present disclosure, an oil pump may be provided. The oil pump may comprise a housing, a mounting passage, a piston and an elastic member. The housing may be formed with an oil inlet, an oil outlet, a low pressure oil chamber communicated with the oil inlet and a high pressure oil chamber communicated with the oil outlet. The mounting passage may be formed in the housing defining a first end communicated with the high pressure oil chamber and a sealed second end, the mounting passage being formed with at least one oil release port and at least one pressure relief port adjacent to the second end for communicating with the low pressure oil chamber. The piston may be slidable along the mounting passage, and the elastic member elastically pressing against the piston to close the first end. The at least one oil release port may be blocked by a circumferential surface of the piston when the first end is closed by the piston, and the piston is movable toward the second end with an oil pressure from the high pressure oil chamber.

With the at least one oil release port and pressure relief port communicating with the low pressure oil chamber, the released oil from the high pressure oil chamber is recycled with the oil in the mounting passage not being discharged outside the oil pump and the pressure relief port may function for air discharging, thus improving efficiency of the oil pumping and reducing loss of energy.

In one embodiment, an engine comprising the above oil pump is provided.

Further, in one embodiment, a vehicle comprising the above engine is provided accordingly.

Other advantages and features of the disclosure are described below.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the disclosure will become apparent and more readily appreciated from the following descriptions taken in conjunction with the drawings in which:

Fig. 1 is a schematic view of an oil pump according to an embodiment of the present disclosure.

Fig. 2 is an exploded perspective view of an oil pump according to an embodiment of the present disclosure.

Fig. 3 is a partial schematic cross sectional view of an oil pump according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Embodiments of the present disclosure will be described in detail in the following descriptions, examples of which are shown in the accompanying drawings, in which the same or similar elements and elements having same or similar functions are denoted by like reference numerals throughout the descriptions. It is to be understood that, the embodiments described herein are merely used to generally understand the present disclosure, but shall not be construed to limit the present disclosure.

In the following, detailed description of an oil pump 100 will be described, in which like numerals refer to like elements through the accompanying figures.

As shown in Figs. 1-3, in one embodiment, the oil pump 100 according to an embodiment of the present disclosure may comprise a housing 1, a mounting passage 114, a piston 116 and an elastic member, for example a compression spring 115 as described in detail below. The housing 1 may be formed with an oil inlet 121, an oil outlet 111, a low pressure oil chamber 113 communicated with the oil inlet 121 and a high pressure oil chamber 112 communicated with the oil outlet 111.

The mounting passage 114 may be formed in the housing 1 defining a first end 1141 communicated with the high pressure oil chamber 112 and a sealed second end 1142. The mounting passage 114 may be formed with at least one oil release port 119 and at least one pressure relief port 117 adjacent to the second end 1142 for communicating with the low pressure oil chamber 113. The piston 116 may be slidable along the mounting passage 114, and the elastic member elastically pressing against the piston 116 to close the first end 1141. In one embodiment, the at least one oil release port 119 may be blocked by a circumferential surface 1161 of the piston 116 when the first end 1141 is closed by the piston 116, and the piston 116 may be movable toward the second end 1142 with an oil pressure from the high pressure oil chamber 112. It should be noted that the "communicating" disclosed in the embodiment may mean communicating directly or communicating indirectly via other parts or structures.

In one embodiment, the elastic member is pre-compressed against the piston 116. To be specific, the elastic member may be implemented as the compression spring 115. However, any elastic spring or elastomer may be alternatively selected according to the desired conditions.

As shown in Figs. 2-3, the oil pump 100 may further comprise a seal cap 118 for sealing the second end 1142 of the mounting passage 114. The seal cap 118 may be detachably connected with the second end 1142 of the mounting passage 114, and the compression spring 115 may be compressed between the piston 116 and the seal cap 118 respectively. In one embodiment, the seal cap 118 may be hermetically fitted with the mounting passage 114 by threads or by interference. During assembly, the piston 116 and the compression spring 115 may be inserted into the mounting passage 114 first, and then the seal cap 118 may be fixed at the second end 1142 in a sealed manner.

In one embodiment, the mounting passage 114 may be formed with a plurality of the oil release ports 119 which are blocked by the circumferential surface 1161 of the piston 116 when the first end 1141 of the mounting passage 114 is closed by the piston 116. The oil release ports 119 may be blocked by the piston 116 when the oil pressure from the high pressure oil chamber 112 is less than or equal to a preload of the compression spring 115. It should be noted that the preload of the compression spring 115 may be adjustable or predefined based on an engine using the oil pump 100 or actual conditions. And the oil release ports 119 may be configured to be opened one by one when the pressure from the high pressure oil chamber 112 larger than the preload of the compression spring 115 is increased gradually.

In one embodiment, the piston 116 may be configured with a hollowed end facing toward the second end 1142 of the mounting passage 114 with an end of the compression spring 115 being received therein.

In one embodiment, the piston 116 may be fitted with the mounting passage 114 by clearance. Thus, some oil may seep toward the second end 1142 via the gap between the circumferential surface 1161 of the piston and the mounting passage 114, and then it may flow through the pressure relief port 117 and enter into the lower pressure oil chamber 113. Thus, the oil passing through the oil inlet 121 may finally flow into the lower pressure oil chamber 113.

In one embodiment, the oil release ports 119 may be distributed in an axial direction of the mounting passage 114 for communicating with the lower pressure oil chamber 113. The oil release ports 119 may have an increased cross section toward the second end 1142 of the mounting passage 114.

To be specific, the oil release ports 119 may be configured into round-holes with the diameter each being increased toward the second end 1142 of the mounting passage 114.

In one embodiment, as shown in Figs. 1 and 2, the housing 1 may comprise a pump case 11 and a pump cover 12, the pump case 11 and the pump cover 12 are fixed by fastening screws (not shown). The oil pump 100 may comprise an inner rotor 2 and an outer rotor 3, the inner rotor 2 and outer rotor 3 are disposed eccentrically within the pump case 11.

When the oil pump 100 is operated, the high pressure oil chamber 112 will produce the oil pressure to press the piston 116 toward the second end 1142 of the mounting passage 114. When the oil pressure from the high pressure oil chamber 112 is less than or equal to the preload of the compression spring 115, the oil release ports 119 are blocked by the piston 116.

When the oil pressure from the high pressure oil chamber 112 which is larger than the preload of the compression spring 115 is increased gradually, the oil release ports 119 are configured to be opened one by one as the piston 116 slides toward the second end 1142, the oil from the high pressure oil chamber 112 will be released to the low pressure oil chamber 113 via the oil release ports 119 gradually. In this process, the oil pressure is decreased gradually, and with the continuous slide of the piston 116, more oil with high pressure flows into the mounting passage 114. Meanwhile, the air in the mounting passage 114 will be released to the oil inlet 121 or the low pressure oil chamber 113 via the pressure relief port 117 to ensure the smooth sliding of the piston 116 in the mounting passage 114.

With the oil release ports 119 distributing in the axial direction of the mounting passage 114 and having an increased cross section toward the second end 1142 of the mounting passage 114, the oil pressure from the high pressure oil chamber 112 may be adjusted in a stepwise manner. The released oil from the high pressure oil chamber 112 is released to the low pressure oil chamber 113 via the oil release ports 119, so the released oil from the high pressure oil chamber is recycling, which may improve the efficiency of the oil pumping and reduce the loss of energy.

In the following, an engine comprising the above oil pump 100 may be provided.

Further, in one embodiment, a vehicle comprising the above engine may also be provided.

Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that changes, alternatives, and modifications may be made in the embodiments without departing from spirit and principles of the disclosure. Such changes, alternatives, and modifications all fall into the scope of the claims and their equivalents.