JP2014013010A - Water pump - Google Patents

Abstract

To provide a water pump that is small in size, has high discharge rate controllability, and can improve the fuel efficiency of a vehicle.
The present invention provides a water pump 1 provided in a vehicle for circulating cooling water, which has a pump portion 2 having an impeller 4 for pumping cooling water, and a shaft connected to the impeller 4. A drive unit 2 that rotationally drives the engine 5 and an engine control unit E that controls the drive unit 2. The drive unit 3 includes a mechanical drive mechanism 10 and an electrical drive mechanism 11 as a pump drive source. The control unit E switches between the mechanical drive mechanism 10 and the electrical drive mechanism 11 based on the engine speed of the vehicle and the fuel injection amount.
[Selection] Figure 1

Description

  The present invention relates to a water pump that is provided in a vehicle and circulates cooling water.

  Conventionally, as a technical document related to a water pump, for example, Japanese Patent Publication No. 2011-518283 is known. This publication shows a coolant pump provided with a mechanical drive means and an electronic motor drive means, wherein the mechanical drive means and the electronic motor drive means can be switched by a clutch.

Special table 2011-518283 gazette

  However, the above-mentioned Japanese translations of PCT publication No. 2011-518283 does not fully describe pump discharge amount control, and does not disclose any pump configuration with high discharge amount controllability. For this reason, there is much room for improvement in the discharge amount control of the water pump.

  Therefore, an object of the present invention is to provide a water pump that is small in size, has high discharge rate controllability, and can improve the fuel efficiency of a vehicle.

  In order to solve the above-mentioned problems, the present invention is a water pump for circulating cooling water provided in a vehicle, and includes a pump unit having an impeller for pumping cooling water, and a rotating shaft connected to the impeller. And a control unit that controls the drive unit. The drive unit includes a mechanical drive unit and an electrical drive unit as a pump drive source, and the control unit includes an engine speed of the vehicle. And switching between mechanical drive means and electrical drive means based on the fuel injection amount.

  According to the water pump of the present invention, since the pump drive source can be switched between the mechanical drive means and the electric drive means, the electric drive means is compared with the case where only the rotation of the conventional engine is used as the pump drive source. Thus, it is possible to appropriately control the pump discharge amount to avoid excessive work of the pump, and to improve the fuel consumption of the vehicle. Further, according to this water pump, when a large pump discharge amount is required, the mechanical drive means is used, so that the pump discharge amount can be increased as compared with the case where only the electric drive means is used as the pump drive source. Therefore, there is no need to increase the size of the electric drive means, which is advantageous for downsizing the pump. Therefore, according to the water pump, high discharge rate controllability can be realized while being small, and the fuel efficiency of the vehicle can be improved.

  In the water pump according to the present invention, the mechanical driving means is means for rotating the rotating shaft by mechanically transmitting the rotation of the engine of the vehicle, and the electric driving means is between the energized coil and the magnet. The rotating shaft may be rotated by the electromagnetic force generated in.

  This water pump uses a mechanical drive mechanism when the engine has a high engine speed and a high load, and uses an electric drive means in other cases. Thus, the fuel efficiency of the vehicle can be improved.

  In the water pump according to the present invention, the mechanical driving means includes a pulley that rotates in conjunction with the rotation of the engine of the vehicle, and one end that is fixed to the rotating shaft and the other end that is pressed against the pulley to rotate the pulley. A transmission unit that transmits to the shaft, and the control unit separates the other end of the transmission unit from the pulley by electromagnetic force by energizing the coil, and rotates the rotating shaft by the electromagnetic force generated by energization of the coil. Thus, the mechanical drive means may be switched to the electrical drive means.

  According to this water pump, switching from the mechanical drive means to the electrical drive means can be realized simply by energizing the coil, and the configuration of the drive section can be simplified and pump control can be facilitated. . Moreover, in this water pump, even if the coil cannot be energized due to some failure, the other end of the transmission portion attracted to the coil is restored and pressed against the pulley, so that the mechanical drive means The water pump can be driven by engine rotation. Therefore, according to this water pump, even if there is an abnormality in the electrical system such as an abnormality in the energization of the coil, the water pump is automatically switched to the mechanical drive mechanism to drive the cooling water. It is possible to avoid a situation that stops and causes engine failure.

  According to the present invention, it is possible to provide a water pump that is small in size, has high discharge rate controllability, and can improve vehicle fuel efficiency.

It is sectional drawing which shows one Embodiment of the water pump which concerns on this invention. It is sectional drawing for demonstrating switching to an electric drive mechanism. It is a graph for demonstrating discharge amount control of the conventional water pump. It is a graph for demonstrating discharge amount control of a water pump in case an engine is a low load state or a medium load state. It is a graph for demonstrating discharge amount control of a water pump in case an engine is a high load state.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  A water pump 1 shown in FIG. 1 is provided in a vehicle such as a truck, for example, and is a pump for circulating cooling water for a diesel engine. The water pump 1 is controlled by an engine control unit E that controls the entire diesel engine. The water pump 1 may be provided for a gasoline engine or other internal combustion engine in addition to a diesel engine.

  The water pump 1 includes a pump unit 2 having an impeller 4 for pumping cooling water, and a drive unit 3 that rotationally drives a shaft (rotating shaft) 5 connected to the impeller 4. FIG. 1 shows the central axis C of the shaft 5.

  The pump unit 2 includes an impeller 4 including a plurality of vanes 4a and a pump housing 6 that forms a flow path of cooling water. In the pump housing 6, in addition to the impeller 4, a cylindrical shaft bearing 7 that rotatably supports the shaft 5 and an annular seal member 8 for sealing around the shaft 5 are provided.

  The drive unit 3 serves as a pump drive source by a mechanical drive mechanism (mechanical drive means) 10 for mechanically rotationally driving the shaft 5 and an electrical drive mechanism (electrical drive mechanism for electrically rotating the shaft 5 ( Electrical drive means) 11.

  The mechanical drive mechanism 10 includes a pulley 12 that rotates in conjunction with an unillustrated engine rotation (crankshaft rotation), and a plurality of transmission units 13 that transmit the rotation of the pulley 12 to the shaft 5. It is.

  The pulley 12 rotates when the rotation of the vehicle engine is transmitted through the engine belt 14 hung on the outer periphery of the pulley 12. An annular ball bearing 15 that rotatably supports the shaft 5 is provided at the center of the pulley 12. Further, a friction pad 16 that comes into contact with the transmission portion 13 is disposed inside the pulley 12.

  The transmission unit 13 is, for example, a long member provided at a predetermined angle with the shaft 5 as the center, and one end side is fixed to the shaft 5 and the other end side contacts the pulley 12 to rotate the pulley 12. It is transmitted to the shaft 5. The transmission unit 13 includes a shaft fixing unit 17, a leaf spring 18, and an armature 19.

  The shaft fixing portion 17 is a portion that fixes one end of the leaf spring 18 to the shaft 5. The shaft fixing portion 17 is fixed to the shaft 5 and fixes one end side of the leaf spring 18 by sandwiching the leaf spring 18 with a screw 17a.

  The leaf spring 18 is a long leaf spring that extends in the radial direction of the shaft 5. The leaf spring 18 biases the armature 19 fixed at the other end toward the pulley 12.

  The armature 19 is a part that is provided on the other end side of the leaf spring 18 and is pressed against the friction pad 16 of the armature 19 by the bias of the leaf spring 18. The armature 19 transmits the rotation of the pulley 12 to the shaft 5 by a frictional force generated between the armature 19 and the friction pad 16. The friction pad 16 is made of a resin or other appropriate material in order to generate an appropriate frictional force. The armature 19 is fixed to the other end side of the leaf spring 18 by a metal bolt / nut 20. The armature 19 may be provided with irregularities on the surface in order to increase the frictional force with the friction pad 16, or may be formed with a layer made of a material having a high frictional force on the surface.

  The electric drive mechanism 11 is a mechanism that rotationally drives the shaft 5 by electromagnetic force generated between the energized coil 21 and the magnet 22. The electric drive mechanism 11 includes a coil 21 fixed to the pump housing 6 and an annular magnet 22 fixed to the shaft 5. The coil 21 and the magnet 22 are resin-molded for improving durability.

  The annular magnet 22 is provided along the side surface of the shaft 5 around the shaft 5, and the coil 21 is provided so as to surround the annular magnet 22. The coil 21 and the magnet 22 face each other in the radial direction of the shaft 5, and the coil 21 functions as a stator and the magnet 22 functions as a mover. Further, the coil 21 is disposed so as to face the other end side (the other end side of the leaf spring 18) of the transmission portion 13 of the mechanical drive mechanism 10 in the extending direction of the central axis C of the shaft 5. .

  Energization of the coil 21 is controlled by the engine control unit E. When the coil 21 is energized, the weak current is returned from the coil 21 side for failure detection.

  In the water pump 1 having the above configuration, the pump drive source can be switched to the mechanical drive mechanism 10 or the electric drive mechanism 11 depending on whether the coil 21 is energized. That is, in the water pump 1, as shown in FIG. 1, when the coil 21 is not energized, the armature 19 of the transmission portion 13 is pressed against the friction pad 16 of the pulley 12 by the bias of the leaf spring 18. Accordingly, the rotation of the pulley 12 that rotates in conjunction with the engine of the vehicle is mechanically transmitted through the transmission unit 13, and the shaft 5 is driven to rotate by the mechanical drive mechanism 10.

  On the other hand, in the water pump 1, as shown in FIG. 2, when the coil 21 is energized, the armature 19 of the transmission unit 13 is electromagnetically attracted to the coil 21, so that the transmission unit 13 is separated from the pulley 12. Then, the rotation of the pulley 12 is not transmitted to the shaft 5. At the same time, when the coil 21 is energized, an electromagnetic force is generated between the coil 21 and the magnet 22, and the shaft 5 is rotationally driven by the electric drive mechanism 11. The armature 19 has an appropriate material and configuration so that it can be attracted to the coil 21 with sufficient force when the coil 21 is energized.

  Thereafter, when the energization of the coil 21 is stopped, the electromagnetic force disappears and the rotation drive of the shaft 5 by the electric drive mechanism 11 is stopped, and the armature 19 is moved to the pulley 12 by the restoring force of the leaf spring 18 in the transmission unit 13. Pressing against the friction pad 16, the rotation of the pulley 12 is transmitted again and the shaft 5 is driven to rotate by the mechanical drive mechanism 10. That is, the transmission unit 13 functions as a clutch mechanism that switches the pump drive source.

  Next, pump drive source switching control in the water pump 1 according to the present embodiment will be described. In the water pump 1 according to this embodiment, the engine control unit E switches between the mechanical drive mechanism 10 and the electrical drive mechanism 11.

Here, FIG. 3 is a graph for explaining the discharge amount control of the conventional water pump. In FIG. 3, a pump discharge amount V ₀ of a water pump that uses only engine rotation as a pump drive source is indicated by a bold line. As shown in FIG. 3, in a water pump that uses only engine rotation as a pump drive source, the pump discharge amount V ₀ increases in proportion to the engine speed.

On the other hand, the required discharge amount of the cooling water required for the water pump 1 varies depending on the load state of the engine. In FIG. 3, the required discharge amount in the full load state (maximum load state) of the engine is a circle plot, the required discharge amount in the medium load state (half maximum load state) is a triangular plot, and the engine low load The required amount of discharge in the state (maximum quarter load state) is shown as a square plot. As shown in FIG. 3, in the conventional water pump, the difference between the pump discharge amount V ₀ indicated by a bold line and each plot is an extra work, which causes a deterioration in fuel consumption of the vehicle.

  In contrast, the engine control unit E of the water pump 1 according to the present embodiment calculates the required discharge amount according to the engine state, and the required discharge amount does not exceed the limit discharge amount Pe of the electric drive mechanism 11. The electric drive mechanism 11 is used as a pump drive source.

  Specifically, the engine control unit E first recognizes the engine load state based on the fuel injection amount of the engine and the EGR [Exhaust Gas Recirculation] gas flow rate. Thereafter, the engine control unit E calculates a required discharge amount of the cooling water required for the water pump 1 based on the engine speed of the vehicle and the engine load state. When the calculated required discharge amount does not exceed the limit discharge amount Pe of the electric drive mechanism 11, the engine control unit E performs discharge amount control using the electric drive mechanism 11 as a pump drive source.

  The limit discharge amount Pe of the electric drive mechanism 11 is not necessarily matched with the performance limit in the specification, and a discharge amount lower than the performance limit may be set as the limit discharge amount Pe for extending the life. Further, it is not always necessary to calculate the required discharge amount, and it may be obtained by map control based on the engine speed or the like. Further, it may be determined directly from the combination of the engine speed and the engine load state whether or not the required discharge amount exceeds the limit discharge amount Pe.

  FIG. 4 is a graph for explaining the discharge amount control of the water pump 1 when the engine is in a low load state or an intermediate load state. In the situation shown in FIG. 4, the engine is in a low load state or a medium load state, and the required discharge amount (square or triangular plot) does not exceed the limit discharge amount Pe of the electric drive mechanism 11. For this reason, the engine control unit E performs discharge amount control by the electric drive mechanism 11.

  In this case, the engine control unit E can appropriately control the rotation of the shaft 5, that is, the pump discharge amount, by controlling the power supplied to the coil 21. That is, in the discharge amount control by the electric drive mechanism 11, it is possible to realize the control of the discharge amount V1 according to the required discharge amount in the low load state (square plot). Similarly, control of the discharge amount V2 according to the required discharge amount (triangular plot) in the middle load state can be realized. Thereby, it can be avoided that the water pump 1 performs extra work exceeding the required discharge amount.

  On the other hand, when the required discharge amount exceeds the limit discharge amount Pe of the electric drive mechanism 11, the engine control unit E switches the pump drive source from the electric drive mechanism 11 to the mechanical drive mechanism 10.

  FIG. 5 is a graph for explaining the discharge amount control of the water pump 1 when the engine is in a high load state. In the situation shown in FIG. 5, when the engine is in a high load state and the engine speed increases, the required discharge amount exceeds the limit discharge amount Pe of the electric drive mechanism 11. Even in this case, when the engine speed is low and the required discharge amount does not exceed the limit discharge amount Pe of the electric drive mechanism 11, discharge amount control by the electric drive mechanism 11 is performed.

  Thereafter, when the engine speed increases and the required discharge amount exceeds the limit discharge amount Pe of the electric drive mechanism 11, the engine control unit E stops the energization of the coil 21 to electrically drive the pump drive source. The mechanism 11 is switched to the mechanical drive mechanism 10. Thereby, the water pump 1 can ensure a sufficient discharge amount V3 by the mechanical drive mechanism 10 using the rotation of the engine when the required discharge amount is large.

  According to the water pump 1 according to the present embodiment described above, since the pump drive source can be switched between the mechanical drive mechanism 10 and the electric drive mechanism 11, only the rotation of the conventional engine is used as the pump drive source. In comparison, the water pump 1 can be prevented from being overworked by appropriate discharge amount control by the electric drive mechanism 11, and the fuel efficiency of the vehicle can be improved. This prevents the pump from circulating the cooling water excessively when the outside air temperature is low, which is advantageous for promoting warm-up of the engine.

  Further, according to the water pump 1, when a large pump discharge amount is required, the mechanical drive mechanism 10 is used, so that the pump discharge amount is compared with a case where only the electric drive mechanism 11 is used as a pump drive source. There is no need to increase the size of the electric drive mechanism 11 in order to cope with the increase, which is advantageous in reducing the size of the pump. Therefore, according to the water pump, high discharge rate controllability can be realized while being small, and the fuel efficiency of the vehicle can be improved. In addition, the miniaturization of the pump (weight reduction, reduction in the number of parts) itself contributes to the improvement of vehicle fuel efficiency.

  Furthermore, according to this water pump, the switching from the mechanical drive mechanism 10 to the electrical drive mechanism 11 can be realized simply by energizing the coil 21, and the configuration of the drive unit 3 can be simplified and pump control can be performed. Can be easily. Moreover, in this water pump, the armature 19 is pressed against the friction pad 16 of the pulley 12 by the restoring force of the leaf spring 18 in the transmission portion 13 even when the coil 21 cannot be energized due to some failure, The rotation of the pulley 12 is transmitted again, and the shaft 5 is rotationally driven by the mechanical drive mechanism 10. Therefore, according to the water pump 1, even when there is an abnormality in the electrical system such as an abnormality in energization of the coil 21, the water pump 1 is automatically switched to drive the water pump 1, so that The situation where the engine breaks down can be avoided by stopping the water circulation.

  The present invention is not limited to the embodiment described above.

  For example, switching between the mechanical drive mechanism and the electrical drive mechanism is not limited to the mechanism described above. For example, an electronically controlled viscous clutch may be employed as the switching mechanism. When an electronically controlled viscous clutch is employed, the rotation of the shaft can be suppressed even during mechanical driving, and unnecessary pump work can be avoided, which is advantageous in improving fuel consumption. Moreover, generation | occurrence | production of a cavitation and abrasion of a seal part can also be suppressed.

  DESCRIPTION OF SYMBOLS 1 ... Water pump 2 ... Pump part 3 ... Drive part 4 ... Impeller 4a ... Vane 5 ... Shaft (rotary shaft) 6 ... Pump housing 7 ... Shaft bearing 8 ... Seal member 10 ... Mechanical drive mechanism (mechanical drive means) 11 ... electric drive mechanism (electric drive means) 12 ... pulley 13 ... transmitting part 14 ... engine belt 15 ... ball bearing 16 ... friction pad 17 ... shaft fixing part 17a ... screw 18 ... leaf spring 19 ... armature 20 ... bolt / nut 21 ... Coil 22 ... Magnet C ... Center axis E ... Engine control unit Pe ... Limit discharge amount V0-V3 ... Pump discharge amount

Claims (3)

A water pump for circulating cooling water provided in a vehicle,
A pump unit having an impeller for pumping the cooling water;
A drive unit that rotationally drives a rotating shaft coupled to the impeller;
A control unit for controlling the driving unit;
With
The drive unit has mechanical drive means and electrical drive means as a pump drive source,
The said control part switches the said mechanical drive means and the said electric drive means based on the engine speed and fuel injection quantity of the said vehicle, The water pump characterized by the above-mentioned. The mechanical drive means is means for rotating the rotating shaft by mechanically transmitting the rotation of the engine of the vehicle.
2. The water pump according to claim 1, wherein the electrical drive means is means for rotating the rotating shaft by electromagnetic force generated between a coil and a magnet that are energized. The mechanical drive means is
A pulley that rotates in conjunction with rotation of the engine of the vehicle;
One end side is fixed to the rotating shaft, and the other end side is pressed against the pulley, thereby transmitting the rotation of the pulley to the rotating shaft, and
The control unit separates the other end side of the transmission unit from the pulley by electromagnetic force by energizing the coil, and rotates the rotating shaft by the electromagnetic force generated by energization of the coil. The water pump according to claim 1 or 2, wherein the mechanical drive means is switched to the electrical drive means.

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