JP4212455B2 - Oil pump - Google Patents

Description

  The present invention relates to an engine-driven oil pump, and more particularly to an oil pump having a function of reducing a pulse pressure at a discharge port.

  As this type of oil pump, one described in Patent Document 1 has been devised.

  This oil pump is a trochoidal pump. The pump chambers between the inner rotor and the outer rotor receive the driving force of the engine to continuously increase or decrease the volume, and the oil sucked in the suction port is added in the pump chamber. It has a basic configuration in which the pressure is discharged and discharged to the discharge port. A closed groove is formed in the upper part of the discharge port, and the upper part of the closed groove is an air chamber for storing air.

Since this oil pump has an air chamber with a closed groove at the discharge port, a plurality of pump chambers open to the discharge port in sequence, and the pulse pressure generated by discharging oil is absorbed by the damping action by the air chamber. can do.
Japanese Utility Model Publication No. 2-43482

  However, since this conventional oil pump has a structure in which the closed groove forming the air chamber is simply opened to the discharge port, when the pulse pressure is generated in the discharge port in a low pressure state, the pulse pressure is reliably ensured by the action of air. However, when pulse pressure is generated in a high pressure state, the pulse pressure cannot be sufficiently reduced.

  Therefore, the present invention is to provide an oil pump that can reliably reduce both the pulse pressure in the low pressure state and the pulse pressure in the high pressure state of the discharge port.

  As means for solving the above-described problems, the present invention provides a pulse pressure reducing chamber that is connected to the discharge port with a plate-shaped partition wall separated from the discharge port, and the partition wall is formed by oil pulse pressure. Deformable.

  In the case of this invention, when a pulse pressure is generated in the discharge port in a low pressure state, the pulse pressure is reduced by the elasticity of air slightly mixed in the oil in the chamber, and when a pulse pressure is generated in the high pressure state, the discharge passage The pulse pressure on the discharge port side and the pulse pressure on the chamber side are made to interfere with each other through the partition wall separating the chamber, thereby reducing the pulse pressure at the discharge port.

  According to a second aspect of the present invention, there is provided a chamber for reducing pulse pressure that is conducted to the discharge port, with a plate-like partition wall provided with respect to the discharge port, and the chamber and the discharge port together with the partition wall have a plurality of housing configurations It may be formed so as to straddle the blocks, and the partition wall may be tapered toward the mating surfaces of the housing constituent blocks.

  In this case, since the vicinity of the tapered mating surface between the housing constituent blocks of the partition walls easily deforms, when the pulse pressure is generated in a high pressure state, the partition walls are likely to fluctuate according to the pulse pressure. Become.

  The chamber is preferably formed such that the longitudinal direction thereof is along the extending direction of the discharge port.

  In this case, since the length of the partition wall can be increased, the partition wall can be more easily deformed and the oil contact area of the partition wall can be increased.

  According to the present invention, the pulse pressure of the discharge port generated in the low pressure state can be reduced by the elasticity of the mixed air in the chamber, and the pulse pressure of the discharge port generated in the high pressure state can be reduced by the oil in the chamber through the partition wall. It can be reliably reduced by the mutual interference action with the pulse pressure.

  Next, an embodiment of the present invention will be described with reference to the drawings.

  The oil pump 1 of this embodiment is attached to a balancer device 2 of a vehicle engine as shown in FIGS. 2 and 3, and a front end portion of a balancer shaft 4B protruding from a support frame 3 of the balancer device 2 is connected to a drive shaft 5. Has been.

  The balancer device 2 has a pair of balancer shafts 4A and 4B that mesh with the synchronous gears 6A and 6B shown in FIG. 2 and rotate synchronously in opposite directions, and one shaft 4A is chained to a crankshaft (not shown) of the engine. The other shaft 4B drives the oil pump 1. Both shafts 4A and 4B of the balancer device 2 rotate at twice the speed of the crankshaft, and the secondary vibrations of the engine are reduced by rotation of weights provided on both shafts 4A and 4B. The balancer device 2 including the oil pump 1 as a whole is disposed inside an oil pan (not shown) at the bottom of the engine.

  The pump housing 7 of the oil pump 1 includes a substantially rectangular base block 8 formed integrally with the front end of the support frame 3 of the balancer device 2 and a cover block 9 attached to the front surface of the base block 8. The outer peripheral edges of both blocks 8 and 9 are connected by a plurality of bolts 10. In the case of this embodiment, the base block 8 and the cover block 9 are made of an aluminum alloy.

  The pump body of the oil pump 1 is constituted by a trochoid pump, and includes an inner rotor 11 that is rotatably attached to the drive shaft 5 and an outer rotor 13 that is rotatably accommodated in the recess 12 of the cover block 9. ing. The inner rotor 11 has a plurality of external teeth formed of a trochoid curve, and the outer rotor 13 is formed of a trochoid curve, and has an internal tooth having one division tooth number larger than the external teeth of the inner rotor 11.

  The inner rotor 11 is arranged eccentrically on the inner peripheral side of the outer rotor 13, the outer teeth are meshed with the inner side of the outer rotor 13 at the most eccentric position, and the remaining portions are in sliding contact with the inner teeth at a plurality of locations in the circumferential direction. It is supposed to be. A plurality of spaces formed between the contact portions of the inner rotor 11 and the outer rotor 13 form a pump chamber 14, and these pump chambers 14 continuously increase or decrease the volume as the inner rotor 11 rotates. It has become.

  As shown in FIG. 1, the pump main body (11, 13) is offset from the upper end of the horizontally long pump housing 7, and is below the pump main body (11, 13) in the pump housing 7. Is formed with a suction port 15 for sucking oil in the oil pan into a suction region of the pump body (11, 13). The pump housing 7 is formed with a discharge port 16 for guiding oil discharged from the discharge region of the pump body (11, 13) to a discharge passage (not shown). The discharge port 16 extends obliquely upward from the pump body (11, 13) by bypassing the protruding end of one balancer shaft 4A in a substantially V shape, and the extending end is connected to the discharge passage.

  Further, the pump housing 7 is formed with an oil chamber 18 that is electrically connected to the discharge port 16 through the communication hole 17 as shown in FIG. The oil chamber 18 is formed on the lower side of the upper extension region 16 a of the discharge port 16 along the longitudinal direction of the port 16, and the end portion of the communication hole 17 is located at the vertical upper position of the oil chamber 18. 16 is communicated. The resonance frequency of the oil chamber 18 is shifted so as not to match the resonance frequency of the discharge port 16.

  As shown in FIG. 4, the discharge port 16 and the oil chamber 18 are formed in half between the joint portions of the base block 8 and the cover block 9. The oil chamber 18 is formed in a substantially rectangular parallelepiped shape along the upper extension region 16 a of the discharge port 16, and the upper wall portion of the chamber 18 along the upper extension region 16 a is a partition wall 21 that separates the discharge port 16 and the chamber 18. It has become. The communication hole 17 having a smaller cross-sectional area than the cross section of the oil chamber 18 is formed at the upper end of the partition wall 21.

  Here, the partition wall 21 is formed by abutment of the base block 8 and the cover block 9, but for the convenience of description, the partition wall configuration portion on the base block 8 side is referred to as the first wall 21a and the partition block configuration on the cover block 9 side. This part is called the second wall 21b.

  The first and second walls 21a and 21b forming the partition wall 21 are formed thin as a whole, and in particular, both are tapered so as to taper toward the mating surfaces as shown in FIG. Is formed. The thin-walled configuration and the tapered shape of the first and second walls 21a and 21b are provided so that both the walls 21a and 21b can be easily changed according to the pulse pressure of the discharge port 16 and the oil chamber 18. When the pulse pressures on the discharge port 16 side and the oil chamber 18 side act on both walls 21a and 21b, these pulse pressures interfere with each other through both walls 21a and 21b. Further, since the partition wall 21 is formed in a substantially planar shape along the upward extending region 16a extending linearly obliquely above the discharge port 16, it is compared with the case where the partition wall 21 is formed in a curved shape. And more easily deformed.

  In FIG. 1, reference numeral 19 denotes a relief valve interposed in a return passage 20 that connects the discharge port 16 and the suction port 15.

  Since the oil pump 1 is configured as described above, when the balancer shaft 4B rotates as the engine starts, the volumes of the plurality of pump chambers 14 change continuously due to the rotation of the inner rotor 11, and the suction port 15 The oil sucked up from the water is continuously discharged to the discharge port 16. At this time, the discharged oil includes a pulse pressure, which is reduced by the oil chamber 18 as follows.

  That is, when the pulse pressure of the discharge port 16 is generated in a low pressure state, the pulse pressure is reduced in the same manner as in a normal oil chamber by the elasticity of the air mixed in the oil in the oil chamber 18. Further, since the oil pump 1 has a thin partition wall 21 separating the discharge port 16 and the oil chamber 18, when the pulse pressure of the discharge port 16 is generated in a high pressure state, the discharge port 16 and the oil chamber 18 are separated from each other. The pulse pressures out of phase interfere with each other through the partition wall 21, and as a result, the pulse pressure at the discharge port 16 is reliably reduced.

  In particular, in this embodiment, the base block 8 and the cover block 9 forming the first and second walls 21a and 21b are formed of an easily deformable aluminum alloy, and the first and second walls 21a and 21b are formed. Since it is formed to be tapered toward the mating surface, when pulse pressure is generated under high pressure conditions, the first and second walls 21a and 21b are large around the mating portion as shown in FIG. As a result, the pulse pressures of the discharge port 16 and the oil chamber 18 can be effectively interfered with each other. Further, the linear extension of the partition wall 21 along the discharge port 16 greatly contributes to facilitating the deformation of the partition wall 21.

  The embodiment of the present invention is not limited to the above-described embodiment. For example, in the above embodiment, the pump body is constituted by a trochoid pump, but a plurality of pump chambers continuously increase / decrease the volume. A vane-type pump or the like may be used as long as it can be used. The oil pump does not necessarily have to be directly connected to the balancer shaft. However, in the case where the oil pump is driven by the balancer shaft that rotates at the double speed of the crankshaft as in this embodiment, the high-frequency pulse is driven. Since the pressure is easily generated, the countermeasure by the oil chamber of the present invention is particularly effective.

  Next, inventions other than the invention described in the claims that can be grasped from the description of the embodiment described above will be described together with the effects thereof.

  (A) The oil pump according to claim 3, wherein the partition wall is linearly extended along the discharge port.

  In this case, the partition wall is more easily deformed, and the pulse pressure can be reduced more effectively.

  (B) The oil pump according to any one of claims 1 to 3 and (a), wherein at least one of the housing constituent blocks forming the mating surfaces of the partition walls is formed of an aluminum alloy.

  In this case, since the partition wall is easily deformed, the effect of reducing the pulse pressure is further increased.

  (C) Driven by a balancer shaft that rotates at a speed twice that of the crankshaft and cancels secondary vibrations of the engine, any one of (A) and (B) above Oil pump as described in

  In this case, the pump shaft rotates at the double speed of the crankshaft together with the balancer shaft, so that the pulse pressure frequency increases as a whole and the pulse pressure level also increases, but this oil pump is in the oil chamber under high pressure. Since the pulse pressure of the discharge port is reduced by the interference action due to the pulse pressure on the chamber side through the partition wall, it is particularly effective under the conditions where the pulse pressure level increases as described above. To do.

  (D) A plurality of external teeth having a trochoidal curve shape are provided on the outer periphery, an inner rotor that is rotationally driven by a drive shaft, and a trochoidal curve shape that is eccentrically disposed on the outer peripheral side of the inner rotor and meshes with the inner rotor on the inner periphery. The oil pump according to any one of claims 1 to 3, and (a) to (c), wherein the oil pump is a trochoid pump including an outer rotor provided with a plurality of internal teeth.

  In this case, a plurality of pump chambers formed between the inner rotor and the outer rotor sequentially open to the discharge port along with the rotation of the drive shaft, and discharge the oil. At this time, the pulse pressure generated in the discharge port passes through the partition wall. It can be reliably reduced by the interference action due to the pulse pressure on the chamber side.

The end elevation which follows the CC line of Drawing 2 which shows the 1st embodiment of the present invention. The top view of the balancer apparatus which shows the embodiment. Sectional drawing which follows the AA line of FIG. 1 which shows the same embodiment. Sectional drawing which follows the BB line of FIG. 1 which shows the same embodiment. Sectional drawing corresponding to FIG. 4 which shows the action | operation in the high voltage | pressure state of the embodiment.

Explanation of symbols

1 ... Oil pump 7 ... Pump housing 8 ... Base block (housing block)
9 ... Cover block (housing block)
14 ... pump chamber 15 ... suction port 16 ... discharge port 18 ... oil chamber (chamber)
21 ... Bulkhead

Claims (4)

In an oil pump in which a plurality of pump chambers continuously increase / decrease the volume by driving by the engine, pressurize the oil sucked in the suction port and discharge it from the discharge port,
The oil chamber for conducting the discharge port, with respect to the discharge port provided at a septal wall, the oil pump to the partition wall, characterized in that the deformable by the pulse pressure of the oil. An oil pump in which a plurality of pump chambers continuously increase or decrease in volume by driving by an engine, pressurizes oil sucked in at a suction port and discharges it from a discharge port, and a pump housing including a discharge port forming portion is an aluminum alloy In which a plurality of housing constituent blocks formed by the above are coupled to each other,
The oil chamber for conducting the discharge port, with respect to the discharge port provided at a septum wall, the oil chamber and the discharge port is formed by straddle the housing building blocks several, said septum housing building blocks of the mutual An oil pump characterized by being tapered toward the mating surface. The oil pump according to claim 1 or 2, wherein the oil chamber is formed such that a longitudinal direction thereof is along an extending direction of the discharge port. Driven by a balancer shaft that rotates at twice the speed of the crankshaft and counteracts secondary vibrations of the engine, multiple pump chambers continuously change volume, pressurize the oil sucked in the suction port, and discharge port A trochoidal oil pump that discharges from
  A pump housing including the discharge port forming portion is configured by mutually connecting a plurality of housing constituent blocks formed of an aluminum alloy, and an oil chamber connected to the discharge port is provided with a partition wall with respect to the discharge port. An oil pump characterized in that the oil chamber and the discharge port are formed across a plurality of housing constituent blocks, and the partition wall is tapered toward a mating surface between the housing constituent blocks. .

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