JP4690855B2 - Trochoid pump - Google Patents

Description

  The present invention provides a rotor housing recess that houses an inner rotor that is attached to a pump shaft so as not to rotate relatively, and an outer rotor that forms a plurality of pump chambers between the inner rotor and meshes with the inner rotor. A pump case comprising one case member and a second case member coupled to the first case member by closing the open end of the rotor accommodating recess leads to a pump chamber in the expansion process among the plurality of pump chambers. The present invention relates to a trochoid pump provided with a suction port and a discharge port leading to a pump chamber in a compression process.

Such a trochoid pump is disclosed in Patent Document 1, for example.
Japanese Patent Laid-Open No. 10-281078

  By the way, in the trochoid type pump, when the clearance between the end faces of the inner rotor and the outer rotor and the pump case increases, the leakage of hydraulic fluid from the discharge side to the suction side increases, and the discharge efficiency decreases. It is difficult to increase the processing accuracy of the rotor accommodating recess provided in the pump case to accommodate the inner rotor and outer rotor to such an extent that the leakage can be tolerated.

  On the other hand, in the one disclosed in the above-mentioned Patent Document 1, in order to prevent an excessive increase in pressure by reducing the discharge amount at a low temperature and to reduce the leakage amount at a high temperature to increase the pump efficiency, the second of the pump cases. A spacer having a larger linear expansion coefficient than the first case member, the inner rotor, and the outer rotor is attached to the case member so as to face the end surfaces of the inner rotor and the outer rotor. The clearance is increased in proportion to the temperature drop.

  With such a trochoid pump disclosed in Patent Document 1, it is possible to reduce the amount of hydraulic fluid leakage at high temperatures, but it is not possible to reduce the amount of leakage at low temperatures.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a trochoidal pump that can contribute to improvement in discharge efficiency by reducing leakage of hydraulic fluid with a simple and small number of parts.

  In order to achieve the above object, an invention according to claim 1 is directed to an inner rotor which is attached to a pump shaft so as not to be relatively rotatable, and an outer which is engaged with the inner rotor by forming a plurality of pump chambers between the inner rotor. A plurality of pumps in a pump case comprising: a first case member that forms a rotor housing recess for housing the rotor; and a second case member that is coupled to the first case member by closing an opening end of the rotor housing recess. In a trochoid pump provided with a suction port leading to a pump chamber in an expansion process and a discharge port leading to a pump chamber in a compression process in the chamber, the axial end faces of the inner rotor and the outer rotor face each other A suction port and a discharge port are provided in a second case member of the pump case, and the inner rotor and the discharge port are provided. The suction port of the pump chamber has an inner periphery corresponding to the outer periphery of the outer rotor between the other axial end surface of the outer rotor and the closed end of the rotor housing recess formed in the first case member. A flat plate-like spacer facing the opening opposite to the discharge port is interposed so as to be inclined so as to be separated from the discharge port and close to the suction port.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the first case member has an axis parallel to the pump shaft at a position corresponding to the space between the suction port and the discharge port. An anti-rotation pin is planted, and the spacer is provided with an engagement hole through which the anti-rotation pin is inserted and engaged so as to allow the inclination of the spacer.

  Furthermore, the invention according to claim 3 is the first case member in addition to the configuration of the invention according to claim 2, in a position corresponding to between the suction end side end of the suction port and the discharge start side end of the discharge port. A single non-rotating pin is implanted in the structure.

  According to the first aspect of the present invention, in the pump chamber formed between the inner rotor and the outer rotor in the space interposed between the closed end of the rotor accommodating recess and the end surfaces of the inner rotor and the outer rotor. Due to the action of the hydraulic pressure of the pump chamber in the compression process and the hydraulic pressure of the pump chamber in the expansion process, the spacer is inclined away from the discharge port and close to the suction port. The clearance between the end surfaces of the inner rotor and the outer rotor is kept small on the side. In other words, it has a simple structure that reduces the number of parts required to insert spacers between the closed end of the rotor housing recess and the end surfaces of the inner rotor and outer rotor, and prevents leakage of hydraulic fluid from the discharge side to the suction side. It is possible to suppress the discharge and improve the discharge efficiency.

  According to the second aspect of the present invention, the rotation of the spacer within the rotor accommodating recess is achieved by the engagement of the spacer with the rotation stop pin implanted in the first case member correspondingly between the suction port and the discharge port. Is prevented, and the spacer is easily inclined with the engaging portion to the detent pin as a fulcrum.

  According to the invention described in claim 3, the single detent pin is implanted in the first case member at a position corresponding to between the suction end side end portion of the suction port and the discharge start side end portion of the discharge port. Therefore, the spacer is easily inclined so as to be closer to the end surfaces of the inner rotor and the outer rotor between the suction start side end of the suction port and the discharge end side end of the discharge port, and the working fluid from the discharge side to the suction side The discharge efficiency can be further reduced and the discharge efficiency can be further improved.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.

  1 to 8 show an embodiment of the present invention, FIG. 1 is a side view of an internal combustion engine, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 3 is a line 3-3 of FIG. 4 is a sectional view taken along line 4-4 in FIG. 3, FIG. 5 is a sectional view taken along line 5-5 in FIG. 3, FIG. 6 is a sectional view taken along line 6-6 in FIG. FIG. 8 is a cross-sectional view taken along line 7 and FIG.

  First, in FIG. 1, an engine body 11 of this internal combustion engine includes a crankcase 12 formed by coupling an upper case 12a and a lower case 12b, a cylinder block 13 formed integrally with the upper case 12a, and the cylinder block 13 The cylinder head 14 is coupled with a head cover 15, and the lower case of the crankcase 12 is coupled with an oil pan 16.

  The crankcase 12 is rotatably supported by a crankshaft 17 having an axis line disposed on a joint surface between the upper case 12a and the lower case 12b constituting the crankcase 12, and the crankshaft 17 and the crankshaft 17 A timing transmission mechanism 21 having an endless cam chain 20 is provided between a pair of camshafts 18 and 19 rotatably supported on the cylinder head 14 with an axis parallel to the cylinder head 14.

  Referring also to FIG. 2, in the crankcase 12, a main shaft 22 and a counter shaft 23 that are rotatably supported by the crankshaft 17 in parallel with the crankshaft 17 can be alternatively established. A transmission mechanism 25 having a gear train group 24 of a plurality of shift stages provided between the main shaft 22 and the counter shaft 23 is accommodated, and the transmission mechanism 25 has a start mounted on one end portion of the main shaft 22. Power from the crankshaft 17 is input via the clutch 26.

  With further reference to FIG. 3, a trochoid oil pump 28 and a water pump 29 are attached to the crankcase 12 below the speed change mechanism 25 with the axes thereof being coaxial, and a pump shaft 30 of the oil pump 28 is provided. The pump shaft 31 of the water pump 29 is coaxially connected so that relative rotation is impossible. In addition, a driven sprocket 32 is fixed to the pump shaft 30 of the oil pump 28, and an endless transmission chain 34 is wound around the drive sprocket 33 fixed to the main shaft 22 of the transmission mechanism 25 and the driven sprocket 32. It is done. That is, the power from the crankshaft 17 is transmitted to the main shaft 22 via the starting clutch 26, and the rotational power of the main shaft 22 is transmitted to the oil pump 28 and the water pump 29.

  An oil strainer 35 is disposed in the oil pan 16, and the oil pump 28 pumps up the oil in the oil pan 16 through the oil strainer 35. An oil filter 36 and an oil cooler 37 are attached to the outer surface of the crankcase 12, and oil discharged from the oil pump 28 is purified by the oil filter 36 and cooled by the oil cooler 37.

  4 to 6, the oil pump 28 accommodates in the pump case 40 an inner rotor 41 that is attached to the pump shaft 30 so as not to rotate relative to the pump shaft 30, and an outer rotor 42 that meshes with the inner rotor 41. The pump case 40 includes a first case member 44 that forms a rotor housing recess 43 having a circular cross section for housing the inner rotor 41 and the outer rotor 42 that mesh with each other, and a lower case of the crankcase 12. A second case member 45 formed integrally with 12b and closing the opening end of the rotor accommodating recess 43 is coupled by a plurality of bolts 39, and is offset from the center of the rotor accommodating recess 43. An inner rotor 4 is connected to the pump shaft 30 that penetrates the first and second case members 44 and 45 in a liquid-tight and rotatable manner. There is mounted by a pin 46 in a relatively non-rotatable manner.

  The outer periphery of the outer rotor 42 having inner teeth 48 that mesh with a plurality of outer teeth 47 formed on the outer periphery of the inner rotor 41 is formed corresponding to the inner periphery of the rotor accommodating recess 43, and The rotation center of the rotor 42 and the rotation center of the inner rotor 41, that is, the axis of the pump shaft 30, are at eccentric positions.

  A plurality of pump chambers 49 are formed between the inner rotor 41 and the outer rotor 42, and the volume of the pump chamber is gradually increased in accordance with the rotation in the rotation direction 50 indicated by the arrows of the inner rotor 41 and the outer rotor 42. 49... That is, the pump port 49 that leads to the pump chamber 49 in the expansion process, and the pump chamber 49 that gradually decreases in volume according to the rotation of the inner rotor 41 and the outer rotor 42. 49 is provided in the second case member 45 of the pump case 40 so as to face the axial end surfaces of the inner rotor 41 and the outer rotor 42. Thus, the oil strainer 35 is connected to the second case member 45 so as to communicate with the suction port 51, and the discharge port 52 is connected to the oil filter 36 and the oil cooler 37 via an oil supply passage (not shown).

  Referring also to FIG. 7, the outer rotor 42 is interposed between the other axial end surfaces of the inner rotor 41 and the outer rotor 42 and the closed end of the rotor housing recess 43 formed in the first case member 44. A flat plate-like spacer 53 having an inner circumference corresponding to the outer circumference of the pump chamber 49 and facing the opening on the side opposite to the suction port 51 and the discharge port 52 of the pump chamber 49. In addition, the spacer 53 is made of the same material as that of the first and second case members 44 and 45, and the other axial end surfaces of the inner rotor 41 and the outer rotor 42 and the rotor housing recess 43 are closed. The distance between the ends is set to such an extent that the spacer 53 can be allowed to tilt.

  Thus, when the oil pump 28 is operated, the hydraulic pressure of the pump chamber 49 in the compression process and the hydraulic pressure of the pump chamber 49 in the expansion process act on the spacer 53. The spacer 53 is inclined so as to be separated from the discharge port 52 and close to the suction port 51 depending on the hydraulic pressure in the pump chambers 49... It is possible to incline so as to be close to the port 51 and is interposed between the closed end of the rotor accommodating recess 43 and the other axial end surfaces of the inner rotor 41 and the outer rotor 42.

  The first case member 44 is provided with a single detent pin 54 having an axis parallel to the pump shaft 30, and the spacer 53 is configured to allow the inclination of the spacer 53. An engagement hole 55 is provided through which the rotation stop pin 54 is inserted and engaged.

  In addition, the detent pin 54 is implanted in the first case member 44 at a position corresponding to the space between the suction port 51 and the discharge port 52. Preferably, the suction end side end portion 51b of the suction port 51 and the discharge port 51 are discharged. A rotation prevention pin 54 is implanted in the first case member 44 at a position corresponding to the discharge start side end portion 52a of the port 52.

  Next, the operation of this embodiment will be described. The pump case 40 of the oil pump 28 includes a first case member 44 that forms a rotor housing recess 43 that houses an inner rotor 41 and an outer rotor 42 that mesh with each other, and a rotor housing. The suction port 51 and the discharge port are formed of a second case member 45 that closes the opening end of the concave portion 43 and is coupled to the first case member 44 and faces one end surface of the inner rotor 41 and the outer rotor 42 in the axial direction. 52 is provided in the second case member 45, and has an inner circumference corresponding to the outer circumference of the outer rotor 42 between the other axial end surfaces of the inner rotor 41 and the outer rotor 42 and the closed end of the rotor housing recess 43. And a flat plate-like shape facing the opening opposite to the suction port 51 and the discharge port 52 of the pump chamber 49. Pacer 53 is interposed as possible to inclined so as to be closer to the suction port 51 as well as away from the discharge port 52.

  According to such an oil pump 28, the spacer 53 interposed between the closed end of the rotor accommodating recess 43 and the end surfaces of the inner rotor 41 and the outer rotor 42 is placed in the compression process of the pump chamber 49. As a result of the action of the hydraulic pressure in the pump chamber 49 and the hydraulic pressure in the pump chamber 49 in the expansion process, the spacer 53 is inclined away from the discharge port 52 and close to the suction port 51. In addition, the clearance between the inner rotor 41 and the outer rotor 42 on the suction port 51 side can be kept small. That is, the operation from the discharge side to the suction side is performed with a simple structure in which the number of parts is simply reduced by interposing the spacer 53 between the closed end of the rotor accommodating recess 43 and the end surfaces of the inner rotor 41 and the outer rotor 42. It is possible to suppress the leakage of the liquid and improve the discharge efficiency.

  Further, at the position corresponding to between the suction port 51 and the discharge port 52, the first case member 44 is provided with a detent pin 54 having an axis parallel to the pump shaft 30, and the spacer 53 has the inclination of the spacer 53 described above. Since the engagement hole 55 for inserting and engaging the detent pin 54 is provided so as to allow the rotation, the rotation of the spacer 53 in the rotor accommodating recess 43 is prevented and the engagement with the detent pin 54 is prevented. With the joint portion as a fulcrum, the spacer 53 is easily inclined, and the leakage of hydraulic fluid from the discharge side to the suction side can be further suppressed.

  Further, since the single detent pin 54 is implanted in the first case member 44 at a position corresponding to between the suction end side end portion 51b of the suction port 51 and the discharge start side end portion 52a of the discharge port 52, the spacer 53 is easily inclined between the suction start side end portion 51a of the suction port 51 and the discharge end side end portion 52b of the discharge port 52 so as to be closer to the end surfaces of the inner rotor 41 and the outer rotor 42, and from the discharge side to the suction side. This makes it possible to further reduce the leakage of the hydraulic fluid and further improve the discharge efficiency.

  The oil pump 28 using such a spacer 53 exhibits the discharge characteristic indicated by the solid line A in FIG. 8, whereas the discharge characteristic of a conventional oil pump not using the spacer 53 is indicated by the dotted line B in FIG. Indicated. That is, it can be seen that the discharge characteristics of the oil pump 28 according to the present invention can be dramatically increased as compared with the conventional oil pump.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the present invention described in the claims. It is.

  For example, although the oil pump of the internal combustion engine has been described in the above embodiment, the present invention can be widely implemented with respect to the trochoid pump.

It is a side view of an internal combustion engine. FIG. 2 is a sectional view taken along line 2-2 of FIG. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. 5 is a sectional view taken along line 5-5 of FIG. FIG. 6 is a sectional view taken along line 6-6 of FIG. FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 4. It is a figure which shows the change of the flow volume characteristic by the presence or absence of a spacer.

Explanation of symbols

30 ... Pump shaft 40 ... Pump case 41 ... Inner rotor 42 ... Outer rotor 43 ... Rotor housing recess 44 ... First case member 45 ... Second case member 49 ...・ Pump chamber 51... Suction port 51 b... Suction end side end 52 of the suction port... Discharge port 52 a... Discharge start side end 53 of the discharge port. Pin 55 ... engaging hole

Claims (3)

  An inner rotor (41) attached to the pump shaft (30) in a relatively non-rotatable manner, and an outer rotor that forms a plurality of pump chambers (49) between the inner rotor (41) and meshes with the inner rotor (41) A first case member (44) that forms a rotor accommodating recess (43) that accommodates (42), and a first case member (44) that is coupled to the first case member (44) by closing the open end of the rotor accommodating recess (43). A pump case (40) comprising two case members (45), a suction port (51) leading to the pump chamber (49) in the expansion process among the plurality of pump chambers (49), and a pump in the compression process In the trochoid pump provided with the discharge port (52) leading to the chamber (49), before the axial end faces of the inner rotor (41) and the outer rotor (42) are exposed. The suction port (51) and the discharge port (52) are provided in the second case member (45) of the pump case (40), and the other axial end surfaces of the inner rotor (41) and the outer rotor (42). And an inner periphery corresponding to the outer periphery of the outer rotor (42) between the closed end of the rotor housing recess (43) formed in the first case member (44) and the pump chamber (49) A flat plate-like spacer (53) facing the opening opposite to the suction port (51) and the discharge port (52) is separated from the discharge port (52) and close to the suction port (51). A trochoid pump characterized in that it can be tilted so as to be inclined.   A locking pin (54) having an axis parallel to the pump shaft (30) is implanted in the first case member (44) at a position corresponding to between the suction port (51) and the discharge port (52). The spacer (53) is provided with an engagement hole (55) through which the detent pin (54) is inserted and engaged so as to allow the inclination of the spacer (53). The trochoid pump according to claim 1.   The single case around the first case member (44) at a position corresponding to the end portion (51b) of the suction port (51) and the discharge start side end portion (52a) of the discharge port (52). A trochoidal pump according to claim 2, characterized in that a stop pin (54) is implanted.

Images