JP5878625B2 - Pump device - Google Patents

Description

  The present invention relates to a pump device including a vacuum pump and a pressure pump.

  An oscillating piston pump, which is a kind of vacuum pump, is known as a reciprocating pump that alternately performs intake and exhaust of air in a pump chamber by reciprocating a piston in a cylinder. Widely used as a pump.

  On the other hand, a composite pump device having two pistons for evacuation and pressurization driven simultaneously by a common motor is also known. As a driving method of this type of pump device, there are known a method of reciprocating the two pistons in mutually opposite phases and a method of reciprocating them in the same phase (for example, Patent Document 1 below). reference).

  The former method, that is, a driving method in which the rotational phases of both pistons are reciprocated by 180 ° has the advantage that the dynamic balance of each pump can be maintained well and vibration of the entire pump device can be reduced. On the other hand, the latter method, that is, a driving method in which both pistons are moved to the top dead center or the bottom dead center at the same time, can reduce the load fluctuation of the driving source and realize a stable operation of the pump device.

JP-A-7-310651

  In recent years, reduction of power consumption of the pump device has been demanded, and further reduction of power consumption is desired also in the above-described composite pump device.

  In view of the circumstances as described above, an object of the present invention is to provide a pump device that can realize further reduction in power consumption.

In order to achieve the above object, a pump device according to an embodiment of the present invention includes a drive motor, a first pump unit for evacuation, and a second pump unit for pressurization.
The drive motor has a first drive shaft and a second drive shaft. The drive motor is configured to be able to rotate the first drive shaft and the second drive shaft around the first axis in synchronization.
The first pump unit responds to the reciprocation of the first piston that reciprocates in the second axial direction orthogonal to the first axis by the rotation of the first drive shaft, and the reciprocation of the first piston. And a first pump chamber whose internal pressure changes.
The second pump unit includes a second piston that reciprocates in the second axial direction by rotation of the second drive shaft, and a second piston whose internal pressure changes according to the reciprocating movement of the second piston. And a pump chamber. The second piston advances with a rotational phase difference of more than 0 ° and less than 80 ° with respect to the first piston.

It is the perspective view seen from the front side of the pump apparatus which concerns on one Embodiment of this invention. It is the perspective view seen from the back side of the said pump apparatus. It is a right view of the said pump apparatus. It is a left view of the said pump apparatus. It is a longitudinal cross-sectional view which shows the structure of a part of vacuum pump part and drive part of the said pump apparatus. It is a schematic diagram explaining the relationship between the eccentric shaft by the side of the vacuum pump part of the said pump apparatus, and the eccentric shaft by the side of a pressurization pump part, (A) is a front view, (B) is from the vacuum pump part side. FIG. It is one experimental result when the pump device is driven so that the pump chamber pressure in the vacuum stage and the pump chamber pressure in the pressurization stage are in phase, and (A) shows the relationship between the pump chamber pressure in the vacuum stage and the piston position. (B) shows the time change of the pump chamber pressure and the piston position in the pressurizing stage, and (C) shows the pressure waveform of the pump chamber in the vacuum stage and the pressure waveform of the pump chamber in the pressurizing stage. The composite waveform is shown. It is one experimental result when the pump device is driven so that the pump chamber pressure in the vacuum stage and the pump chamber pressure in the pressurization stage are in opposite phases, and (A) shows the relationship between the pump chamber pressure in the vacuum stage and the piston position. (B) shows the time change of the pump chamber pressure and the piston position in the pressurizing stage, and (C) shows the pressure waveform of the pump chamber in the vacuum stage and the pressure waveform of the pump chamber in the pressurizing stage. The composite waveform is shown. It is an experimental result which shows the relationship between the rotation phase difference of the piston of a pressurization stage with respect to the piston of a vacuum stage, and the consumption current of a motor.

  The internal pressure of the pump chamber in the oscillating piston pump periodically changes as the piston reciprocates. For example, when the piston moves from bottom dead center to top dead center, the volume of the pump chamber decreases, so the internal pressure changes in an increasing direction. When the piston moves from top dead center to bottom dead center, the volume of the pump chamber increases. Therefore, the internal pressure changes in the decreasing direction. At this time, in the case of a vacuum pump, the internal pressure of the pump chamber changes in a pressure range below the atmospheric pressure (negative pressure), and in the case of a pressure pump, the internal pressure of the pump chamber in a pressure range above the atmospheric pressure (positive pressure). Changes.

  However, according to the experiments by the present inventors, even when the piston for the vacuum pump and the piston for the pressure pump are reciprocated in the same phase as described above, the internal pressures of both pump chambers change synchronously. It was confirmed that there was a phase difference in the pressure change between the two pump chambers. Further, it was confirmed that the load on the motor does not become the minimum value even if the rotation phase of both the pistons is controlled so that the internal pressure change of both pump chambers becomes the same phase by the vacuum pump and the pressure pump.

  Therefore, in the present invention, in order to realize further reduction in power consumption of the pump device, the pump device is configured as follows.

That is, a pump device according to an embodiment of the present invention includes a drive motor, a first pump unit for evacuation, and a second pump unit for pressurization.
The drive motor has a first drive shaft and a second drive shaft. The drive motor is configured to be able to rotate the first drive shaft and the second drive shaft around the first axis in synchronization.
The first pump unit responds to the reciprocation of the first piston that reciprocates in the second axial direction orthogonal to the first axis by the rotation of the first drive shaft, and the reciprocation of the first piston. And a first pump chamber whose internal pressure changes.
The second pump unit includes a second piston that reciprocates in the second axial direction by rotation of the second drive shaft, and a second piston whose internal pressure changes according to the reciprocating movement of the second piston. And a pump chamber. The second piston advances with a rotational phase difference of more than 0 ° and less than 80 ° with respect to the first piston.

  According to the experiments by the present inventors, the piston top dead center and the pressure peak position of the pump chamber almost coincide with each other in the first pump unit for evacuation, but the piston in the second pump unit for pressurization. The top dead center and the pressure peak position in the pump chamber did not match. In particular, in the second pump section, it was confirmed that the pump chamber reached a pressure peak before the piston reached top dead center.

  The rotational phase difference can be set as appropriate within a range of more than 0 ° and less than 80 °. For example, a stable power consumption reduction effect can be obtained at 40 ° ± 30 °, and further consumption within a range of 40 ° ± 15 °. A power reduction effect can be obtained. Thus, by optimizing the rotational phase difference, the pump device can be stably operated with low power consumption.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 to 4 are external views showing a pump device according to an embodiment of the present invention. FIG. 1 is a perspective view seen from the front side, FIG. 2 is a perspective view seen from the back side, and FIG. FIG. 4 is a left side view.

  The pump device 1 of the present embodiment includes a vacuum pump unit 11 (first pump unit) as a vacuum stage, a pressurizing pump unit 12 (second pump unit) as a pressurizing stage, a vacuum pump unit 11, And a drive unit 13 that drives the pressure pump unit 12 in common. The pump device 1 is used as, for example, a gas pressure booster used in a fuel cell system, a vacuum and a pressure pump used in a medical analyzer.

  The vacuum pump unit 11 and the pressurizing pump unit 12 typically have a common configuration, and are configured as a swing piston pump in the present embodiment.

  The pump device 1 includes a first casing 101 that constitutes a part of the vacuum pump unit 11, a second casing 102 that constitutes a part of the pressure pump unit 12, and a second part that constitutes a part of the drive unit 13. And a pump case 100 including three casings 103.

  FIG. 5 is a vertical cross-sectional view showing a partial configuration of the vacuum pump unit 11 and the drive unit 13. In FIG. 5, an X axis, a Y axis, and a Z axis indicate three axial directions that are orthogonal to each other. In addition, since the pressurization pump part 12 has the structure similar to the vacuum pump part 11, the vacuum pump part 11 is mainly demonstrated here.

  The vacuum pump unit 11 includes a first casing 101, a piston 21, a connecting rod 22 (rod member), and an eccentric member 23.

  The first casing 101 includes a case main body 110, a cylinder 111, a pump head 112, and a pump head cover 113. The case body 110, the cylinder 111, the pump head 112, and the pump head cover 113 are integrated with each other so as to be stacked in the Z-axis direction.

  The case main body 110 is connected to the third casing 103 that houses the motor M, and has a through hole 110h through which the connecting rod 22 passes. The case main body 110 includes a fixed portion 110 a that fixes the bearing 32 that rotatably supports the drive shaft 131 of the motor M, and a cylindrical portion 110 b that houses the coil 132 of the motor M. The drive shaft 131 is disposed parallel to the Y-axis direction (first axial direction), and rotates around the Y-axis by driving the motor M. The bearing 32 is disposed between the main body of the motor M and the eccentric member 23.

  The cylinder 111 is disposed between the case main body 110 and the pump head 112, and accommodates the piston 21 slidably in the Z-axis direction. The pump head 112 is disposed between the cylinder 111 and the pump head cover 113, and includes an intake valve 112a and an exhaust valve 112b. The pump head cover 113 is disposed on the pump head 112 and has an intake chamber 113a that communicates with the intake port 114a and an exhaust chamber 113b that communicates with the exhaust port 114b. As shown in FIGS. 1 and 2, the intake port 114a and the exhaust port 114b are provided on the side surfaces of the pump portions 11 and 12 facing each other.

  The piston 21 has a disk shape, and is fixed to the first end 221 of the connecting rod 22 via a screw member 25. The piston 21 forms a pump chamber 26 between the piston 21 and the pump head 112. The piston 21 changes the internal pressure of the pump chamber 26 by reciprocating in the direction parallel to the Z-axis direction (second axial direction) inside the cylinder 111. The piston 21 performs a predetermined pump action by alternately sucking and exhausting the pump chamber 26 via the intake valve 112a and the exhaust valve 112b.

  The connecting rod 22 connects the piston 21 and the eccentric member 23 to each other. The connecting rod 22 has a first end 221 connected to the piston 21 and a second end 222 connected to the eccentric member 23. The first end 221 is formed in a circular shape having substantially the same diameter as the piston 21. A disc-shaped seal member 24 is attached between the piston 21 and the first end 221. The peripheral portion of the seal member 24 is bent toward the pump chamber 26 so as to be slidable on the inner peripheral surface of the cylinder 111.

  In the pressurizing pump section 12, the peripheral edge of the seal member is bent toward the pump chamber side, contrary to the above example.

  A fitting hole 222 a that fits the eccentric shaft 232 of the eccentric member 23 is formed in the second end portion 222 of the connecting rod 22. A bearing 31 that rotatably supports the eccentric shaft 232 is mounted in the fitting hole 222a.

  The eccentric member 23 connects the drive shaft 131 of the motor M housed in the third casing 103 and the connecting rod 22 to each other. The eccentric member 23 has a substantially cylindrical base block 230. A drive shaft 131 is connected to the surface of the base block 230 on the motor M side, and an eccentric shaft 232 is formed on the surface of the connecting rod 22 side. The shaft axis of the eccentric shaft 232 is eccentric with respect to the drive shaft 131 so as to be deflected as the drive shaft 131 rotates. The drive shaft 131 is connected to the base block 230 by screws 41 fastened to the side peripheral surface of the base block 230.

  A counterweight 51 is attached to the eccentric member 23. The counterweight 51 is fixed to the side peripheral portion of the eccentric member 23 by a fixing screw 42 fastened to the side peripheral surface of the base block 230. The counterweight 51 rotates together with the piston 21 and has a function of canceling vibration generated when the connecting rod 22 rotates around the eccentric shaft 232 as the drive shaft 131 rotates. The counterweight 51 is disposed at a position deviated in the direction opposite to the eccentric direction of the eccentric shaft 232 with respect to the drive shaft 131.

  In the vacuum pump unit 11 configured as described above, the eccentric member 23 rotates around the drive shaft 131 by driving the motor M, so that the eccentric shaft 232 is offset from the drive shaft 131. Revolves around the drive shaft 131 along a circumference having a radius corresponding to. The connecting rod 22 connected to the eccentric shaft 232 converts the rotation of the drive shaft 131 into the reciprocating movement of the piston 21 inside the cylinder 111. That is, the piston 21 reciprocates in the Z-axis direction while swinging in the X-axis direction in FIG. As a result, intake and exhaust of the pump chamber 26 are alternately performed, and a predetermined vacuum exhaust action by the vacuum pump unit 11 is obtained.

  On the other hand, the pressurizing pump unit 12 is configured in the same manner as the vacuum pump unit 11, and the drive shaft 131 protrudes also to the pressurizing pump unit 12 side and is connected to an eccentric shaft (not shown) of the pressurizing pump unit 12. The Thus, the pressurizing pump unit 12 is driven by the common motor M simultaneously with the vacuum pump unit 11 and performs a predetermined pressurizing (pressurizing) action.

  Here, the vacuum pump unit 11 and the pressurizing pump unit 12 are driven in mutually different phases. That is, in the present embodiment, the piston 21 (second piston) of the pressurizing pump unit 12 advances with a rotational phase difference of more than 0 ° and less than 80 ° with respect to the piston 21 (first piston) of the vacuum pump unit 11. Configured to do.

  In this embodiment, the positions of the eccentric shafts 232 of the pumps 11 and 12 are made different so that the pistons have the rotational phase difference as described above. According to the present embodiment, since the eccentric member 23 is fixed to the drive shaft 131 only by fastening the screw 41, the relative positions of the eccentric shafts 232 in the two pumps 11 and 12 can be easily adjusted.

  Further, since the position of the counterweight fixed to the eccentric member 23 correlates with the eccentric direction of the eccentric shaft 232, the rotational phase difference between the pistons 21 can be easily confirmed even from the outside of the pump device 1. be able to. That is, as shown in FIGS. 1 to 4, the counter weight 52 of the pressurizing pump unit 12 is rotated in the rotational direction of the drive shaft 131 (centered on the Y axis in FIG. 3) with respect to the counter weight 51 of the vacuum pump unit 11. It is fixed at a position advanced in the clockwise direction (counterclockwise around the Y axis in FIG. 4) by the predetermined rotational phase difference (over 0 ° and less than 80 °).

  6A and 6B are schematic views for explaining the relationship between the eccentric shaft 232v on the vacuum pump unit 11 side and the eccentric shaft 232c on the pressure pump unit 12 side, and FIG. FIG. 4B is a side view seen from the vacuum pump unit 11 side. As shown in FIG. 6B, the eccentric shaft 232c on the pressure pump side is provided at a position advanced by a predetermined rotational phase difference φ from the eccentric shaft 232v on the vacuum pump unit 11 side. For this reason, the piston 21v on the vacuum pump unit 11 side and the piston 21c on the pressure pump unit 12 side are driven with a phase difference φ shifted from each other, and the piston 21c is driven by a time corresponding to the phase difference φ relative to the piston 21v. Reach top dead center early.

  The rotational phase difference φ is set in an appropriate range of more than 0 ° and less than 80 °. Thereby, compared with the case where both pistons 21v and 21c are driven by the same phase (phi = 0), the power consumption of the motor M can be made small. Further, by setting φ = 40 ° ± 15 °, the above-described low power consumption operation of the motor M can be stably maintained.

  FIG. 7 (A) is an experimental result showing the time change between the pump chamber pressure and the piston position in the vacuum pump, and FIG. 7 (B) shows the time change between the pump chamber pressure and the piston position in the pressurizing pump. It is one experimental result shown. In the figure, the solid line represents the experimental results during 50 Hz operation, and the broken line represents the experimental results during 60 Hz operation.

  The pump head used in the experiment was 40 [kPa (absolute pressure)] in the vacuum stage (vacuum pump) and 220 [kPaG (gauge pressure)] in the pressurization stage (pressurization pump). The internal pressure of the pump chamber was measured through a tube inserted in the pump chamber in an airtight manner. The piston position used the output of the accelerometer attached to the lower part of the connecting rod. The cylinder diameter of each stage of the pump was 37 mm, the eccentric amount of the eccentric shaft was 3.3 mm, and the rotational speed of the motor was about 1400 rpm / 1700 rpm (50 Hz / 60 Hz). The conditions of the experimental results shown in FIGS. 8 and 9 are the same.

  In the vacuum stage, the pump chamber pressure changes in the same phase in synchronization with the piston position (FIG. 7A), whereas in the pressurization stage, the pump chamber pressure does not synchronize with the piston position. A phase difference is generated between them (FIG. 7B). More specifically, a pressure peak appears in the pump chamber before the pressurizing stage piston reaches top dead center.

  From the above experimental results, even if the pistons of the vacuum stage and the pressurizing stage are driven in the same phase, the pump chamber pressures of the vacuum stage and the pressurizing stage do not change in the same phase, and the pump chamber of the pressurizing stage It was confirmed that the maximum pressure was reached earlier than the vacuum stage pump chamber.

  In addition, when the pump device is configured so that the internal pressure changes in both pump chambers are in opposite phases between the first pump portion and the second pump portion, the pistons of the pump portions are driven in phase with each other. It was confirmed by experiments that the power consumption of the drive motor can be reduced as compared with the above.

  Here, the time variation of the internal pressure is in reverse phase typically means that the pressure waveforms in the two pump chambers have a phase of 180 °, but the present invention is not limited to this. It is only necessary to have a phase relationship that can be interpreted as a relationship of. Here, the reverse phase in a substantial sense can be defined as a phase relationship in which power consumption is smaller than when both pistons are driven in the same phase.

  Pump with a predetermined phase difference between the pressure stage piston and the vacuum stage piston so that the pressure waveform of the vacuum stage pump chamber pressure and the pressure stage pump chamber pressure have the same phase. When the apparatus is configured, the pressure stage piston is set to a rotational phase difference that is advanced by more than 180 degrees and less than 260 degrees with respect to the vacuum stage piston. Experimental results when the rotational phase difference is 220 ° are shown in FIGS. FIG. 7C shows a combined waveform of the pressure waveform of the pump chamber in the vacuum stage and the pressure waveform of the pump chamber in the pressurization stage.

  On the other hand, a predetermined phase difference is provided between the pressure-stage piston and the vacuum-stage piston so that the pressure waveform of the vacuum-stage pump chamber pressure and the pressure waveform of the pressure-stage pump chamber pressure are in opposite phases. When the pump device is configured, the pressure stage piston is set to a rotational phase difference advanced by more than 0 ° and less than 80 ° with respect to the vacuum stage piston. The experimental results when the rotational phase difference is 40 ° are shown in FIGS. FIG. 8A shows the time change between the pump chamber pressure and the piston position in the vacuum stage, and FIG. 8B shows the time change between the pump chamber pressure and the piston position in the pressurization stage. FIG. 8C shows a combined waveform of the pressure waveform of the pump chamber in the vacuum stage and the pressure waveform of the pump chamber in the pressurization stage.

  FIG. 9 is an experimental result showing the relationship between the rotational phase difference of the pressurizing stage piston relative to the vacuum stage piston and the current consumption of the motor. The rotational phase difference on the horizontal axis represents the phase advance angle of the pressurizing stage piston with respect to the vacuum stage piston (the phase angle in which the pressurizing side piston advances from the vacuum side piston in the rotational direction of the drive shaft).

  As shown in FIG. 9, it can be seen that the current value of the motor changes in accordance with the rotational phase difference φ of the pressurizing stage piston with respect to the vacuum stage piston. This is considered to be related to the balance of pressure change between the pump chambers in each stage.

  In the present experimental example, the rotational phase difference φ with the lowest current value is 40 °, and the pressure waveforms in the pump chambers of the respective stages at this time are in an opposite phase relationship as shown in FIGS. 8A and 8B. is there. In this case, the combined waveform of the internal pressures of the pump chambers of each stage is as shown in FIG. 8C, and the pump chamber pressures of the respective stages cancel each other. As a result, the current consumption of the motor is minimized. Conceivable.

  On the other hand, under a driving condition in which the internal pressures of the pump chambers of the respective stages are in phase with each other (the rotational phase difference of the pressurizing stage piston is + 220 ° with respect to the vacuum stage piston), as shown in FIG. It is thought that the internal pressure of the pump chambers at each stage overlaps to cause periodic load fluctuations in the motor, and this causes the current consumption value to increase.

  Also, as shown in FIG. 9, in the range where the rotational phase difference φ is greater than 0 ° and less than 80 °, the motor frequency is 50 Hz or 60 Hz, compared with the case where the rotational phase difference φ = 0 ° (360 °). It was confirmed that the drive current can be reduced. In particular, within the range of the rotational phase difference φ = 40 ° ± 30 °, the current value could always be made smaller than when φ = 0 ° regardless of the difference in power supply frequency. Furthermore, within the range of φ = 40 ° ± 15, the power consumption can be further effectively reduced, and the current value can be reduced by about 4.1% at 50 Hz and about 2.2% at 60 Hz. It was.

  Furthermore, by setting the phase difference φ to 40 ° ± 15 °, not only the current consumption can be reduced, but also vibrations generated when the pump device 1 is driven can be reduced. According to the experiments of the present inventors, for example, when φ = 40 °, each of X, Y, and Z is compared to when the pistons in the vacuum stage and the pressurizing stage are in phase (φ = 0 °). It was confirmed that any vibration acceleration in the axial direction (see FIG. 1) can be reduced. This vibration reduction effect was confirmed at both power supply frequencies of 50 Hz and 60 Hz.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

  For example, in the above embodiment, the vacuum pump unit 11 and the pressurizing pump unit 12 constituting the pump device are each constituted by an oscillating piston pump. However, the present invention is not limited to this, and other reciprocating type such as a diaphragm pump is used. Each pump may be composed of a piston pump.

  Moreover, although the above embodiment demonstrated and demonstrated the pump apparatus which has a single drive motor and two pump parts as an example, a plurality of pump units comprised by the said drive motor and two pump parts ( For example, the present invention can be applied to a pump device provided with two sets.

DESCRIPTION OF SYMBOLS 1 ... Pump apparatus 11 ... Vacuum pump 12 ... Pressure pump 21,21v, 21c ... Piston 26 ... Pump chamber 51,52 ... Counter weight 131 ... Drive shaft 232,232v, 232c ... Eccentric shaft M ... Motor

Claims (3)

A drive motor having a first drive shaft and a second drive shaft and capable of rotating the first drive shaft and the second drive shaft around the first axis in synchronization with each other; ,
A first piston that reciprocates in a second axial direction orthogonal to the first axis by rotation of the first drive shaft, and a first pressure that changes in accordance with the reciprocation of the first piston. A first pump part for evacuation having a pump chamber;
A second piston that reciprocates in the second axial direction by rotation of the second drive shaft; and a second pump chamber in which an internal pressure changes in accordance with the reciprocation of the second piston. A second pump portion for pressurization in which the second piston advances with a rotational phase difference of more than 0 ° and less than 80 ° with respect to the first piston;
A pump device comprising: The pump device according to claim 1,
The rotational phase difference is 40 ° ± 15 ° Pump device. The pump device according to claim 1,
The first pump unit rotates around the first drive shaft and a first eccentric member connected to the first drive shaft, and is fixed to the first eccentric member . 1 counter weight,
The second pump portion rotates around the second drive shaft with the second eccentric member coupled to the second drive shaft and the rotational phase difference with respect to the first counterweight. And a second counterweight fixed to the second eccentric member .

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