JP2009162250A - Engine oil pump drive - Google Patents

Abstract

In an engine oil pump drive device in which rotational power of an engine can be input to a rotating member housed in a pump housing of an oil pump via power transmission means, the rotational speed is higher than necessary with a simple and compact configuration. In order to prevent the oil pump from rotating, the size of the oil pump is reduced and the pump efficiency of the oil pump is improved.
Rotational power is transmitted from a power transmission means 15A to a rotating member 13A of an oil pump 11A in a state where the rotational speed of rotational power transmitted from an engine E to a power transmission means 15A is less than a predetermined rotational speed. However, the rotational power transmission from the power transmission means 15A to the rotating member 13A is interrupted by the power transmission / interruption switching means 18A.
[Selection] Figure 1

Description

  The present invention relates to an engine oil pump drive device in which rotational power of an engine can be input to a rotating member housed in a pump housing of an oil pump via power transmission means.

An engine oil pump generally employs a mechanical drive system of a positive displacement pump such as a trochoid pump or a gear pump because of its reliability, simple structure, and compactness. In this case, the oil pump is often driven by a crankshaft or driven by a shaft that is linked to and connected to the crankshaft by a gear or a chain to rotate at a constant speed or increase / decrease. In many cases, the rotational speed of the oil pump increases as the speed increases. Further, as disclosed in Patent Document 1, there is a type in which a variable displacement oil pump is connected to a pump impeller of a torque converter in an automatic transmission, or an oil pump is connected to an electric motor having a variable rotation speed. .
JP-A-61-88056

  By the way, the positive displacement oil pump is small and can secure a large flow rate, but it has a narrow rotation speed range that can efficiently secure the required discharge amount due to the occurrence of cavitation, internal leakage, etc. The effect of changes in viscosity on pump performance is also significant.

  In recent years, vehicle engines tend to be smaller and faster in order to pursue thermal efficiency, but the engine rotation speed range has been expanded as a result of the desire to keep the idle rotation speed low, and consistency with the rotation speed range of the oil pump. Is difficult. For example, when trying to secure a sufficient discharge rate with a sufficient oil pump during low speed operation of the engine, not only the pump efficiency decreases due to the occurrence of cavitation near the maximum speed of the engine, but also the commerciality due to the occurrence of noise, erosion, and corrosion. , Durability may be impaired.

  In addition, various control devices using hydraulic pressure are installed in vehicle engines for convenience and thermal efficiency improvement. Conventionally, hydraulic pressure has been reduced even in idling conditions at high oil temperatures where the pump discharge pressure is the lowest. In order to guarantee the operation of the device, it is common to increase the capacity of the oil pump. When the oil temperature is low or the engine speed is high, the discharge pressure of the oil pump becomes excessive to protect the hydraulic system. The pressure regulating valve is opened and the oil pumped up by the oil pump is discharged into the oil reservoir. Such an increase in the capacity of the oil pump and the release of excess oil not only deteriorate the engine efficiency, but also promote the foaming of the circulating oil, leading to further reduction in the efficiency of the oil pump, and various tribological It becomes a factor of a malfunction. In the first place, the oil discharge amount required to keep the oil pressure for lubrication and device control constant is almost independent of the engine rotation speed, and the oil discharge amount of the oil pump is proportional to the engine rotation speed. Inevitably, there are more problems as mentioned above.

  Patent Document 1 includes a slide ring that is housed in a pump housing and supported so as to be swingable in the pump housing, and a drive rotor and an outer ring that are disposed inside the slide ring, and a drive rotor. Driven by a vane-type oil pump and an electric motor configured to change the discharge amount of the oil pump by changing the amount of eccentricity between the outer ring and the slide ring by swinging the slide ring An oil pump is disclosed, and the oil discharge amount of the oil pump is controlled regardless of the engine rotation speed. However, the structure disclosed in Patent Document 1 has a complicated structure, This leads to an increase in the size of the electric motor.

  The present invention has been made in view of such circumstances, and has a simple and compact configuration so that the oil pump does not rotate at an unnecessarily high rotational speed. An object of the present invention is to provide an improved oil pump drive device for an engine.

  In order to achieve the above object, an invention according to claim 1 is an oil pump driving apparatus for an engine, in which the rotational power of the engine can be input to the rotating member accommodated in the pump housing of the oil pump through the power transmission means. A state in which the rotational power transmitted from the engine to the power transmission means is less than a predetermined rotational speed, and the rotational power is transmitted from the power transmission means to the rotational member; Power transmission / cut-off switching means for switching between a state in which rotational power transmission from the power transmission means to the rotating member is cut off when the rotational speed is equal to or higher than a predetermined number of rotations is provided.

  According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the predetermined rotational speed is a value near the rotational speed of the rotating member when the pump efficiency of the oil pump is the highest. It is characterized by that.

  According to a third aspect of the invention, in addition to the configuration of the first or second aspect of the invention, the power transmission / cutoff switching means is a centrifugal clutch.

  According to a fourth aspect of the present invention, in addition to the configuration of the third aspect of the invention, the oil pump is an inner rotor that is the rotating member that meshes with the pump housing and is housed in the pump housing. A trochoid pump having an outer rotor, wherein the power transmission / cutoff switching means is accommodated in the pump housing.

  Furthermore, the invention according to claim 5 is characterized in that, in addition to the configuration of the invention according to any one of claims 1 to 3, the power transmission / cutoff switching means is configured separately from the oil pump. .

  According to the first aspect of the present invention, when the rotational speed of the rotational power transmitted from the engine to the power transmission means is less than the predetermined rotational speed, the rotational power is transmitted from the power transmission means to the rotating member of the oil pump. Since the power transmission from the power transmission means to the rotating member is interrupted when the rotational speed of the rotating member exceeds a predetermined rotational speed due to the rotational power transmission from the means, the power transmission / shut-off switching means can be used simply and easily. With a compact configuration, it is possible to reduce the size of the oil pump and prevent the oil pump from rotating at an unnecessarily high rotation speed, and to improve the pump efficiency of the oil pump, thereby reducing the fuel consumption of the engine. Can do.

  According to the second aspect of the present invention, when the pump efficiency of the oil pump is the maximum, the rotational power is transmitted from the power transmission means to the rotating member in a state less than the value added with the rotational speed, and the pump efficiency is the highest. Since the rotational power transmission to the rotating member is cut off as the rotational speed of the rotating member increases beyond the value of the rotational speed, the oil pump is at the highest pump efficiency even when the engine rotational speed increases. The cost can be reduced by eliminating the need for a pressure regulator or the like.

  According to the third aspect of the present invention, since the power transmission / cut-off switching means is a centrifugal clutch, the power transmission / cut-off switching means can be configured at low cost.

  According to the invention described in claim 4, since the oil pump is a trochoid pump and the centrifugal clutch is housed in the pump housing of the oil pump, it is possible to prevent the apparatus from being enlarged, particularly as in a four-wheeled vehicle or the like. Moreover, the oil pump can be suitably applied to a large oil pump.

  Furthermore, according to the invention described in claim 5, versatility can be improved by configuring the power transmission / cutoff switching means separately from the oil pump.

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

  1 to 5 show a first embodiment of the present invention. FIG. 1 is a schematic view showing the configuration of an oil pump drive device, FIG. 2 is a transverse sectional view of the oil pump, and FIG. FIG. 4 is a diagram showing a change in pump efficiency with respect to the engine speed, and FIG. 5 is a diagram showing a change in pump engine speed with respect to the engine speed.

  First, in FIG. 1, an oil pump 11A is a trochoid pump in which an inner rotor 13A and an outer rotor 14 as rotating members meshing with each other are accommodated in a pump housing 12, and the oil pump 11A includes an engine E Rotational power can be input via the power transmission means 15A. Moreover, the power transmission means 15A has a pump shaft 17A that is linked to and connected to the crankshaft 16 of the engine E. Between the pump shaft 17A and the inner rotor 13A, power transmission / cutoff switching means is provided. A centrifugal clutch 18A is interposed. The centrifugal clutch 18A transmits power from the power transmission means 15A to the inner rotor 13A in a state where the rotational speed of the rotational power transmitted from the engine E to the power transmission means 15A is less than a predetermined rotational speed. The state where the power transmission from the pump shaft 17A to the inner rotor 13A is cut off is switched according to the increase in the rotational speed of the inner rotor 13A to a predetermined rotational speed or more by the power transmission from the power transmission means 15A.

  2 and 3, the pump housing 12 of the oil pump 11A has a housing main body 19 having an end wall 19a on one end side and formed in a dish shape, and an opening end of the housing main body 19 is closed. The pump shaft 17A has an axis at a position eccentric from the pump housing 12, and is rotatable by the end wall 19a of the housing main body 19 and the cover 20. Supported.

  The outer rotor 14 is rotatably fitted to the housing main body 19 of the pump housing 12, and the inner rotor 13A is disposed coaxially with the pump shaft 17A so as to mesh with the outer rotor 14, A pump chamber 21 is formed between the rotor 13 </ b> A and the outer rotor 14.

  The centrifugal clutch 18A is housed in the pump housing 12 so as to be disposed in the housing hole 22 provided in the inner rotor 13A and opened to the end wall 19a and the cover 20 side. One end portion of the inner rotor 13A is rotatably supported by a support shaft 23 parallel to the shaft 17A, and the other end portion is fitted into the outer periphery of the pump shaft 17A and can be frictionally engaged. A pair of weights 24, 24 on which 24a ... are formed, and the weights 24 ... so as to exert a spring force that presses the fitting recesses 24a ... of the weights 24 ... against the outer periphery of the pump shaft 17A. And springs 25, 25 that are contracted between the inner rotors 13A.

  Thus, when the rotational speed of the pump shaft 17A to which rotational power is transmitted from the engine E is low, the fitting recesses 24a are frictionally engaged with the outer periphery of the pump shaft 17A by the spring force exerted by the springs 25. As a result, the inner rotor 13A rotates together with the pump shaft 17A. However, when the rotational speed of the pump shaft 17A and the inner rotor 13A is increased to a predetermined rotational speed or more, centrifugal force acting on the weights 24. When the spring force becomes larger, the weights 24 rotate around the axis of the support shaft 23 in a direction to move the fitting recesses 24a away from the outer periphery of the pump shaft 17A, and in this state the pump shaft 17A As a result, slippage occurs between the inner rotor 13A and the power transmission from the pump shaft 17A to the inner rotor 13A. Rotational speed of the motor 13A is not said predetermined rotational speed or more. When the rotational speed of the inner rotor 13A becomes less than the predetermined rotational speed due to the disconnection of the centrifugal clutch 18A, the centrifugal clutch 18A enters the power transmission state again. As a result, the rotational speed of the pump shaft 17A exceeds the predetermined rotational speed. In the region, the centrifugal clutch 18A is in a half-clutch state, and the rotational speed of the inner rotor 13A is maintained at the predetermined rotational speed.

  By the way, the pump efficiency of the oil pump 11A gradually increases as the rotational speed of the inner rotor 13A increases as shown in FIG. 4, but after reaching the highest pump efficiency at a certain rotational speed Npm, the rotational speed is increased. The predetermined rotational speed at which the centrifugal clutch 18A cuts off the power transmission is the rotation of the pump shaft 17A and the inner rotor 13A when the oil pump 11A has the highest pump efficiency. The number, that is, a value near the rotation speed Npm is set.

  Here, the value near the rotation speed Npm is preferably within a range of about 10% with respect to the rotation speed Npm. In addition, as shown in FIG. 4, the pump efficiency with respect to the engine speed gradually increases as the engine speed increases when the engine speed is lower than the engine speed Npm, whereas the engine speed increases with the engine speed. In a state higher than Npm, it sharply decreases as the engine speed increases. Therefore, the width x1 (for example, Npm × 0.07) on the side where the engine speed is lower than the rotation speed Npm is smaller than the width x2 (for example, Npm × 0.03) on the side where the engine speed is higher than the rotation speed Npm. More preferably, the predetermined rotational speed at which the centrifugal clutch 18A interrupts power transmission is set to a value larger than (Npm−Npm × 0.07) and smaller than (Npm + Npm × 0.03). preferable. By doing in this way, the dispersion | variation in the rotation speed which the centrifugal clutch 18A clutches in can be absorbed efficiently.

  The rotational speed Npm varies depending on the oil temperature. For example, it is desirable to predetermine the rotation speed Npm based on a normally used oil temperature (for example, 80 ° C.), thereby further improving the pump efficiency. Can be expected.

  Next, the operation of the first embodiment will be described. Between the pump shaft 17A in the power transmission means 15A and the inner rotor 13A in the oil pump 11A, the power is transmitted from the engine E to the pump shaft 17A of the power transmission means 15A. The rotational speed of the inner rotor 13A is greater than or equal to a predetermined rotational speed by transmitting power from the pump shaft 17A to the inner rotor 13A when the rotational speed of the rotating power is less than the predetermined rotational speed. A centrifugal clutch 18A that switches between a state in which the transmission of power from the pump shaft 17A to the inner rotor 13A is cut off in response to the increase in speed is provided. Therefore, when the rotational speed of the pump shaft 17A in the power transmission means 15A and the inner rotor 13A in the oil pump 11A exceeds a predetermined rotational speed, power transmission from the pump shaft 17A to the inner rotor 13A of the oil pump 11A is interrupted, When power transmission from the pump shaft 17A is interrupted and the rotational speed of the inner rotor 13A falls below a predetermined rotational speed, rotational power is transmitted from the front pump shaft 17A to the inner rotor 13A. The oil pump 11A is reduced in size by a simple and compact configuration using a centrifugal clutch 18A that switches between power transmission and interruption between the 17A and the inner rotor 13A so that the oil pump 11A does not rotate at an unnecessarily high rotational speed. Oil pump 11 It is possible to pump efficiency, it is possible to reducing fuel consumption and thus the engine E.

  Further, the predetermined rotational speed at which the centrifugal clutch 18A switches between power transmission and shut-off is a value near the rotational speed Npm of the inner rotor 13A when the pump efficiency of the oil pump 11A is the highest. Therefore, as shown in FIG. Even if the rotational speed is increased, the inner rotor 13A of the oil pump 11A rotates around the rotational speed Npm where the pump efficiency is the highest, so that a pressure regulator or the like is not required and the cost can be reduced.

  By setting the speed ratio between the crankshaft 16 and the pump shaft 17A so that the rotational speed Npm is close to the rotational speed of the pump shaft 17A and the inner rotor 13A during the idle operation of the engine E, the oil pump 11A The pump capacity can be minimized. In this case, it is premised that oil is lubricated between the weight 24... And the pump shaft 17A in the half clutch state of the centrifugal clutch 18A, and an increase in the slip torque at the maximum rotation speed of the engine E is the oil pump 11A. It is necessary to pay attention to the setting of the speed ratio between the crankshaft 16 and the pump shaft 17A so as not to exceed the merit of miniaturization.

  In addition, since the power transmission / cut-off switching means is the centrifugal clutch 18A, the power transmission / cut-off switching means can be constructed at low cost, and the centrifugal clutch 18A is housed in the pump housing 12 of the oil pump 11A. The oil pump 11A can be suitably applied to a large oil pump such as a four-wheel vehicle.

  FIG. 6 shows a second embodiment of the present invention. The parts corresponding to those of the first embodiment are indicated by the same reference numerals and are not described in detail.

  The oil pump 11B is a trochoid pump in which an inner rotor 13B and an outer rotor 14 as rotating members meshing with each other are accommodated in a pump housing 12 so as to form a pump chamber 21 therebetween, and a power transmission means 15A. A centrifugal clutch 18B, which is a power transmission / cutoff switching means, is interposed between the pump shaft 17A and the inner rotor 13B. The centrifugal clutch 18B has a predetermined rotational speed of the pump shaft 17A and the inner rotor 13A. A state in which power transmission from the power transmission means 15A to the inner rotor 13B is interrupted when the rotational speed becomes equal to or higher than the rotational speed, and from the pump shaft 17A when the rotational speed of the inner rotor 13A falls below a predetermined rotational speed. The state in which the rotational power is transmitted to the inner rotor 13B is switched.

  The centrifugal clutch 18B is accommodated in the pump housing 12 so as to be disposed in the accommodation hole 28 provided in the inner rotor 13B, and slides on one diameter line of the pump shaft 17A. A pair of weights 29, 29 that are supported by the inner rotor 13B as possible and that are formed with fitting recesses 29a on the inner end of the pump shaft 17A that can be fitted and frictionally engaged with the outer periphery of the pump shaft 17A; A spring that is contracted between the outer ends of the weights 29 and the inner rotor 13B so as to exert a spring force that presses the fitting recesses 29a of the weights 29 to the outer periphery of the pump shaft 17A. 30 and 30.

  Thus, in a state where the rotational speed of the pump shaft 17A and the inner rotor 13B is low, the fitting recess 29a is frictionally engaged with the outer periphery of the pump shaft 17A by the spring force exerted by the springs 30 ... It rotates together with the pump shaft 17A, but when the rotational speed of the pump shaft 17A and the inner rotor 13B becomes larger than the predetermined rotational speed, the centrifugal force acting on the weights 29 becomes larger than the spring force of the springs 30. The weights 29 are slid in a direction in which the fitting recesses 29a are separated from the outer periphery of the pump shaft 17A, thereby interrupting power transmission from the pump shaft 17A to the inner rotor 13B. .

  The same effects as those of the first embodiment can be obtained by the second embodiment.

  7 and 8 show a third embodiment of the present invention. FIG. 7 is a longitudinal sectional view of a part of the power transmission means and the oil pump, taken along line 7-7 in FIG. 8 is a cross-sectional view taken along line 8-8 in FIG.

  First, in FIG. 7, an oil pump 11C is a trochoid pump in which an inner rotor 13C and an outer rotor 14 as rotating members that mesh with each other form a pump chamber 21 therebetween and are accommodated in a pump housing 12. The rotational power of the engine E can be input to the oil pump 11C via the power transmission means 15B.

  The power transmission means 15B is rotatably supported by the pump housing 21 of the oil pump 11C and is connected to the inner rotor 13C so as not to be relatively rotatable, and is relatively non-rotatable and coaxial with the pump shaft 17B. The first transmission shaft 31 to be connected, the second transmission shaft 32 arranged coaxially with the first transmission shaft 31, and the power transmission / cutoff switching means interposed between the first and second transmission shafts 31 and 32 The second transmission shaft 32 is interlocked and connected to the crankshaft 16 (see FIG. 1) of the engine E.

  The centrifugal clutch 18C is configured such that the rotational speed of the rotational power transmitted from the engine E to the power transmission means 15B, that is, the rotational speed of the second transmission shaft 32 is less than a predetermined rotational speed and the second transmission shaft 32 to the first transmission shaft 31 and The state in which the rotational power is transmitted to the pump shaft 17B and the inner rotor of the oil pump 11C from the power transmission means 15B when the rotational speed of the inner rotor 13C, the pump shaft 17B and the first transmission shaft 31 exceeds the predetermined rotational speed. The state where the rotational power transmission to 13C is cut off is switched.

  Referring also to FIG. 8, a pair of support portions 31a and 31a projecting outward along one diameter line of the first transmission shaft 31 at the end of the first transmission shaft 31 on the second transmission shaft 32 side. And a fitting shaft portion 32a that is coaxially fitted to the first transmission shaft 31 so as to be relatively rotatable with respect to the end portion of the second transmission shaft 32 on the first transmission shaft 31 side. In addition, a dish-shaped housing 33 having a cylindrical portion 33a surrounding the support portions 31a is integrally provided.

  The centrifugal clutch 18 </ b> C is provided with a pair of shoes 34 slidably contacting the inner surface of the cylindrical portion 33 a at one end, and supported by a support shaft 35 parallel to the axis of the first transmission shaft 31 so as to be swingable. The supporting portions 31a and the weights 36 are provided so as to exert a spring force that urges the weights 36 in a direction in which the weights 36 and 36 and the shoes 34 are pressed against the inner surface of the cylindrical portion 33a. It is comprised with the springs 37 and 37 provided between the other ends.

  In such a centrifugal clutch 18C, when the rotational speed of the second transmission shaft 32 is low, the spring force exerted by the springs 37 is pressed against the inner periphery of the shoe 34. Rotational power from the second transmission shaft 32 is transmitted to the first transmission shaft 31 and the pump shaft 17B, and the pump shaft 17B and the inner rotor 13C rotate together with the second transmission shaft 32. When the rotational speed of the pump shaft 17B and the inner rotor 13C is greater than a predetermined rotational speed, the centrifugal force acting on the weights 36 is greater than the spring force of the springs 37, so that the weights 36 are The shoes 34 are rotated about the axis of the support shafts 35 in a direction to separate the shoes 34 from the inner periphery of the cylindrical portion 33a, and in this state, between the second transmission shaft 32 and the first transmission shaft 31. Ri is generated, will be the power transmission from the power transmission means 15B to the inner rotor 13C is cut off, the rotational speed of the inner rotor 13C is not said predetermined rotational speed or more. Further, when the rotational speed of the inner rotor 13C becomes less than the predetermined rotational speed due to the disconnection of the centrifugal clutch 18C, the centrifugal clutch 18C again enters the power transmission state, and as a result, the rotational speed of the second transmission shaft 31 becomes the predetermined rotational speed. In the above region, the centrifugal clutch 18C is in a half-clutch state, and the rotational speed of the inner rotor 13C is maintained at the predetermined rotational speed.

  According to the third embodiment, the same effects as in the first and second embodiments can be obtained, and the centrifugal clutch 18C is configured separately from the oil pump 11C, so that versatility is enhanced. be able to.

  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.

It is the schematic which shows the structure of the oil pump drive device of 1st Example. It is a cross-sectional view of an oil pump. It is sectional drawing which follows the 3-3 line of FIG. It is a figure which shows the change of the pump efficiency with respect to rotation speed. It is a figure which shows the change of the pump rotation speed with respect to an engine rotation speed. It is a cross-sectional view of the oil pump of the second embodiment. It is a longitudinal cross-sectional view of a part of power transmission means and oil pump of 3rd Example, Comprising: It is sectional drawing which follows the 7-7 line | wire of FIG. FIG. 8 is a view taken along arrow 8 in FIG. 7.

Explanation of symbols

11A, 11B, 11C ... Oil pump 12 ... Pump housings 13A, 13B, 13C ... Inner rotor 14 as rotating member ... Outer rotor 15A, 15B ... Power transmission means 18A, 18B, 18C ... Centrifugal clutch E as engine for switching power transmission / disconnection ... Engine

Claims (5)

  The rotational power of the engine (E) is input to the rotating member (13A, 13B, 13C) accommodated in the pump housing (12) of the oil pump (11A, 11B, 11C) via the power transmission means (15A, 15B). In the engine oil pump drive apparatus, the power transmission means (15A, 15B) in a state where the rotational speed of the rotational power transmitted from the engine (E) to the power transmission means (15A, 15B) is less than a predetermined rotational speed. ) From the power transmission means (15A, 15B) when the rotational power is transmitted to the rotating members (13A to 13C) and the rotational speed of the rotating members (13A to 13C) is equal to or higher than the predetermined rotational speed. Power transmission / shut-off switching means (18A, 18B, 18C) for switching between a state in which the rotational power transmission to the rotating members (13A to 13C) is shut off is provided. Oil pump drive device for an engine, characterized in that.   2. The engine according to claim 1, wherein the predetermined rotational speed is a value near the rotational speed of the rotating member (13 </ b> A to 13 </ b> C) when the pump efficiency of the oil pump (11 </ b> A to 11 </ b> C) is maximum. Oil pump drive device.   The engine oil pump drive device according to claim 1 or 2, wherein the power transmission / cut-off switching means (18A to 18C) is a centrifugal clutch.   The oil pumps (11A to 11C) are engaged with the pump housing (12) and are inner members and outer rotors (14) which are the rotating members (13A to 13C) accommodated in the pump housing (12). The engine oil pump drive device according to claim 3, wherein the power transmission / cut-off switching means (18A, 18B) is housed in the pump housing (12).   The engine oil pump drive device according to any one of claims 1 to 3, wherein the power transmission / cutoff switching means (18C) is configured separately from the oil pump (11C).

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