JP5364068B2 - Gear pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gear pump capable of discharging a fluid sucked from a suction port from a discharge port by mutually meshing and rotating a drive gear having a tooth shape at an outer circumference and a driven gear having a tooth shape at an inner circumference. <P>SOLUTION: Disks 3 are concentrically attached to one side or both sides of a drive gear 1. Through-holes 8, 8, ... of the same number as the number of teeth of the drive gear 1 are provided through a disk outer circumferential part. A torque limiter is attached so that the phase is changed by the slip when a rotational speed of the drive gear 1 is increased and a specific region is exceeded. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a gear pump capable of suppressing a discharge amount during high-speed rotation.

  In general, a pump is used to pump out a fluid, and the pump is a device that gives mechanical energy from the outside and converts it into kinetic energy of the fluid. There are various types of pumps, and these pumps are used properly according to their applications. The gear pump targeted by the present invention is a pump provided with a mechanism for limiting the discharge amount in the high-speed rotation region.

  By the way, vane pumps and piston pumps are frequently used as representative of variable displacement pumps, but the vane pumps and piston pumps are inferior in mechanical efficiency of gear pumps at low pressure and low rotation. Since one gear pump has a constant discharge amount per one rotation, when the rotation speed increases, the discharge amount becomes more than necessary, and as a result, the loss increases. That is, a discharge amount that is not used is sent out in the high rotation range, and energy is consumed for that purpose, resulting in a loss. That is, even when such a gear pump is used in a vehicle automatic transmission, an unnecessary discharge amount is generated, resulting in power loss.

  FIG. 5 is a schematic view showing a gear pump. In FIG. 5, (a) shows a drive gear, (b) shows a driven gear, and an inner small drive gear (A) on the driving side and an outer side on the driven side. Large driven gears (B) can mesh with each other and rotate. The driven gear (B) is housed in a case and is rotatably supported. The drive gear (A) can be rotated with the shaft by fitting the shaft into the central shaft hole (C).

In the gear pump shown in the figure, the number of teeth of the drive gear (A) is Z ₂ = 9 and the number of teeth of the driven gear (B) is Z ₁ = 10. Therefore, the gear tooth number difference is Z ₁ −Z ₂ = 1, there is no crescent, and all the internal teeth of the driven gear (B) are meshed with the external teeth of the drive gear (A). By the way, when the suction port (d) is located on the right side and the discharge port (e) is located on the left side, if the drive gear (b) rotates in the right direction (clockwise), the fluid from the suction port (d) Is sucked in and discharged from the discharge port (e) on the left side.

  In the gear pump shown in the figure, when the drive gear (A) rotates, the tooth profile space between the suction port (d) and the driven gear (b) formed between the suction port (d) and the discharge port (e) increases. Is sucked from the suction port (d). And it discharges from the discharge port (e) where a tooth profile space is shrunk | reduced again with rotation of a drive gear (a). Therefore, in the gear pump, fluid is discharged as the drive gear (A) rotates, so that the discharge amount inevitably increases as the rotational speed increases.

  FIG. 6 is a schematic view showing a gear pump (f) incorporated in an automatic transmission for a vehicle. The gear pump (f) includes a torque converter (g) and a speed change mechanism ( H) is installed during. The torque converter (g) is a fluid coupling including a pump impeller, a turbine runner, and a lock-up damper device, and transmits engine torque to the speed change mechanism (h) through the input shaft.

  For this purpose, the torque converter (g) is filled with hydraulic oil, which is stored in an oil pan and circulated by the gear pump (f). Further, the hydraulic oil supplied to the transmission mechanism (h) is also circulated by the gear pump (f). By the way, a sleeve (re) that is provided on the inner diameter portion of the pump impeller and serves as an oil pump drive shaft is fitted in a shaft hole (c) of a drive gear (b) of the gear pump (f). Accordingly, when the pump impeller rotates, the drive gear (A) rotates, and when the rotational speed of the pump impeller increases, the gear pump (F) inevitably rotates at a high speed. As a result, the amount of hydraulic oil discharged from the gear pump (f) increases.

  However, the amount of hydraulic oil required in the torque converter (g) and the transmission mechanism (h) is not proportional to the increase / decrease in rotational speed from a predetermined region. FIG. 7 is a graph showing the relationship between the rotation speed and the discharge amount of the gear pump, and the discharge amount is proportional to the rotation speed. For this reason, the shaded area is an unnecessary discharge amount, and a large amount of hydraulic oil is discharged. Supply is wasted. In order to discharge a large amount of hydraulic oil, a large amount of energy is required, resulting in a reduction in power transmission efficiency from the engine.

  The "engine oil pump" according to Japanese Utility Model Laid-Open No. 1-83194 is eccentrically meshed with an outer rotor rotatably incorporated in a pump body and an inner rotor fixed to a shaft driven by engine power. The oil is sucked into the outer rotor from the suction port opened in the pump body by the rotation of the inner rotor and the outer rotor, and discharged to the discharge port, and the oil is discharged into the pump body according to the oil discharge pressure. An oil discharge variable member that moves in the rotational direction is provided.

  For example, the oil discharge amount variable member (timing rotor) moves in the direction opposite to the outer rotor due to an increase in oil discharge pressure, thereby speeding up the opening timing of the discharge port and causing the oil to flow backward to the suction port. That is, once the oil discharge state is converted into oil pressure (discharge pressure), the variable device is operated, and therefore, there is a difference between the rotational speed change and the discharge pressure rise timing, and correct control cannot be performed.

The “engine oil supply device” according to Japanese Patent Application Laid-Open No. 2005-140022 is an oil supply device that can reliably ensure the amount of oil to be supplied to the working oil supplied portion even when the engine rotates at high speed.
Therefore, the pump body provided with the suction port, the first discharge port, and the second discharge port, the oil supply passage, the first oil passage, the second oil passage, and the oil pressure of the working oil to the supply oil passage. And a return oil path for returning hydraulic oil from a hydraulic control valve having a valve element that operates to the suction port, and the valve element includes a first valve chamber, a second valve chamber, and a hydraulic oil storage portion. When the hydraulic pressure of the working oil to the feed oil passage is within a predetermined range, the working oil from the second discharge port is fed to the feed oil passage via the first valve chamber, and the working oil to the feed oil passage When the hydraulic pressure is larger than the predetermined range, the working oil from the second discharge port can be fed to the feed oil passage via the second valve chamber.

This engine oil supply device has two discharge ports, has a hydraulic control valve with a valve element that operates in response to the hydraulic pressure of the hydraulic oil to the oil supply passage, and switches the hydraulic control valve to operate the hydraulic oil Is returned to the suction port. Therefore, the structure of the oil supply device of the engine is very complicated, and a shift occurs between the change of the rotation speed and the pressure rise to the oil supply passage, and correct control cannot be performed.
“Engine oil pump” according to 1-83194 "Engine oil supply device" according to JP-A-2005-140022

  Thus, the conventional gear pump has the above-described problems. The problem to be solved by the present invention is this problem, and provides a gear pump that is configured so that the discharge rate does not increase even when the rotational speed of the drive gear increases, and that has a simple structure.

  The gear pump according to the present invention is configured such that the drive gear and the driven gear mesh with each other, and the driven gear rotates together with the rotation of the drive gear so that fluid can be sucked and discharged, and the basic structure is shown in FIG. Common to conventional gear pumps. In the gear pump of the present invention, a disk is attached to the side surface of the drive gear, and the disk rotates together with the drive gear.

  The disk has the same number of holes as the number of teeth of the drive gear, and the holes are arranged in the same phase as the valleys of the drive gear. The disk is mounted on the shaft of the drive gear, but a torque limiter is interposed between them, and when a certain rotational speed is exceeded, the connection between the disk and the drive gear is cut off, causing a shift in the phase of the disk. The suction or discharge of the fluid into the gear pump is performed through the hole in the disk. However, when the phase is shifted, the passage area of the hole is reduced, and the suction port and the discharge port communicate with each other through the hole. Here, the specific structure of the torque limiter for connecting the disks is not limited. The disk is attached to one side or both sides of the drive gear.

In the gear pump of the present invention, a disk is attached to at least one side of the drive gear,
Fluid is sucked or discharged from a hole provided in the disk. However, when the rotation speed of the gear pump increases, the torque limiter provided between the drive gear and the disc shifts the phase of the disc by changing the centrifugal force of the limiter member and the drag torque of the disc. To do. As a result, the amount of fluid suction or discharge decreases.

  In addition, since the timing at which the suction port and the discharge port communicate with each other through a phase-shifted hole is generated, the delivery pressure associated with the rotation of the drive gear is reduced, and as a result, the discharge amount is reduced. Therefore, as the rotational speed of the gear pump increases, the amount of fluid discharged does not increase proportionally, and the amount of power required to rotationally drive the drive gear is reduced by suppressing the amount of discharge. The gear pump of the present invention has a simple structure in which a disk is simply attached to the side surface of the drive gear, but an effect of suppressing the discharge amount can be obtained and the manufacturing cost can be reduced.

(A) It is an Example which shows the gear pump which concerns on this invention, (b) is the state which removed the disk of the front side. A specific example of a disk attached to a drive gear. When the disc mounted on the drive gear is out of phase. A gear pump according to the present invention incorporated in an automatic transmission of a vehicle. Conventional gear pump. A conventional gear pump built in an automatic transmission of a vehicle. The graph which shows the relationship between the rotation speed of a gear pump, and discharge amount.

  FIG. 1 (a) is an embodiment showing a gear pump according to the present invention, and FIG. 1 (b) shows a state where a disk is removed. In the figure, 1 is a drive gear, 2 is a driven gear, and 3 is a disk. (B) with the disc 3 removed is the same in structure as the gear pump shown in FIG. 5, the drive gear 1 disposed on the inner side and serving as the driving side is small, and the outer driven gear serving as the driven side. 2 is large and can mesh with each other and rotate.

  The driven gear 2 is housed in a casing, and the outer periphery is guided by a casing positioning member 4 arranged at an eccentric position with respect to the drive gear 1 so as to be rotatably supported. The drive gear 1 has a shaft 5 at its center. The shaft 5 is provided with a shaft hole 6. The drive gear 1 can be rotated by a shaft that fits in the shaft hole 6.

  The disk 3 is attached to the shaft 5 of the drive gear 1 and can rotate with the drive gear 1. Moreover, a torque limiter capable of relative rotation when a torque exceeding a certain level is applied is attached. FIG. 2 shows a specific example of the disk 3 alone. The disk 3 has a shaft hole 7 in the center, and a plurality of holes 8, 8.. Yes. And between the holes 8,8 ... is formed with partition parts 21,21 .... Here, the number of the holes 8, 8... Is the same as the number of teeth of the drive gear 1. However, the shape and size of the hole 8 are not particularly limited.

  And the small slot 9, 9, ... is extended in the radial direction on the internal peripheral surface of the axial hole 7. As shown in FIG. A small coil spring 10 is fitted in the slot 9, and a ball 11 is disposed at the tip, and the ball 11 is partially fitted in a groove 12 formed in the shaft 5 of the drive gear 1. The ball 11 is biased by the spring force of the coil spring 10 fitted in the groove 9, and the ball 11 is engaged with the groove 12 of the shaft 5, so that the disk 3 can rotate together with the drive gear 1.

  However, when the rotational speed of the drive gear 1 increases, the centrifugal force acting on the coil spring 10 and the ball 11 fitted in the slot 9 increases, and the ball 11 tends to move away from the groove 12 of the shaft 5, and further the disk 3 The drag torque increases and the ball 11 is disengaged from the groove 12. As a result, the phase of the disk 3 shifts and the position of the hole 8 changes.

  As shown in FIG. 1 (a), the disk 3 has holes 8, 8,... Formed in the outer peripheral portion thereof positioned in the valleys 13, 13,. .. are arranged so as to be located at the peaks 17, 17..., And rotate together with the drive gear 1 in this state. In FIG. 1A, 14 indicated by a dotted line is a suction port, 15 is a discharge port, and the drive gear 1 and the disk 3 rotate clockwise in the direction of the arrow. The suction area of the suction port 14 increases with rotation, and the discharge area of the discharge port 15 decreases with rotation.

  Therefore, the fluid passes through the holes 8, 8... Provided in the disk 3 from the suction port 14, flows into the tooth-shaped spaces 16, 16... Of the drive gear 1 and the driven gear 2, and is confined. The fluid confined in the tooth profile spaces 16, 16... Passes through the holes 8, 8. In this state, it is the same as a conventional gear pump without the disk 3 attached.

  By the way, when the rotational speed of the drive gear 1 increases, the disk 3 rotates relative to each other and the phase of the hole 8 provided in the disk 3 changes. FIG. 3 shows a case where the phase of the disk 3 has changed, but the holes 8, 8... Of the disk 3 are located at the positions of the peaks 17, 17. Therefore, the opening through which the suction port 14 indicated by the dotted line passes through the holes 8, 8... Of the disk 3 and flows into the tooth profile spaces 16, 16.

Further, the suction port 14 and the discharge port 15 can communicate with each other through the hole 8 of the disk 3 by the relative rotation of the disk 3 and the phase change. For example, the fluid flows from the suction port 14 through the hole 8a into the tooth-shaped space 16a of the drive gear 1 and the driven gear 2, and this space 16a communicates with the space 16b opened in the adjacent hole 8b.
That is, the space 16a and the space 16b are the same continuous space. The space 16b is partitioned by the mountain of the drive gear 1 and the mountain of the driven gear 2 contacting each other, but flows through the hole 8b of the disk 3 and flows into the space 16c. That is, if the disk 3 does not exist, the spaces are separated from each other, but are communicated with each other through the hole 8b of the disk 3.

  The space 16c is the same space as the space 16d. Since the space 16d is connected to the discharge port 15, the pressure on the suction port 14 side and the pressure on the discharge port 15 side are balanced to suppress the discharge amount. As shown in FIG. 1, if the holes 8, 8... Are located in the valleys 13, 13. Are not communicated with each other through the holes 8, 8..., But a phase shift occurs as shown in FIG. If 8 ... is located in the peaks 17, 17 ..., the tooth profile spaces 16, 16 ... communicate with each other through the holes 8, 8 .... However, because of the repetition of the state in which the fluid is communicated by the rotation and the state in which the fluid is not communicated, the pressures on the fluid suction port side and the discharge port side are balanced, and the fluid does not flow backward due to a negative pressure.

  Therefore, even if the rotational speed of the drive gear 1 is increased, more fluid than necessary is not discharged. As a result, energy consumption accompanying the increase in the discharge amount is suppressed, and the power transmission efficiency of the automatic transmission is improved. Here, the size and shape of the hole 8 of the disk 3 are such that when the disk 3 is relatively rotated and the phase is changed and the hole 8 is at the position of the peak 17 of the drive gear 1, the suction port 14 side and the discharge port 15 side. In the state where the peak 17 of the drive gear 1 and the peak of the driven gear are in contact with each other, it is only necessary that the two tooth profile spaces communicate with each other through the hole 8.

  FIG. 4 is a schematic diagram showing a mounting structure of a gear pump built in an automatic transmission of a vehicle. The gear pump 18 is mounted between the torque converter 19 and a transmission mechanism housed in the transmission. A sleeve 20 that is located on the inner diameter of the pump impeller and serves as an oil pump drive shaft is fitted in the shaft hole 6 of the drive gear 1 of the gear pump 18. Therefore, when the pump impeller rotates, the drive gear 1 rotates. When the rotational speed of the pump impeller increases, the gear pump 18 necessarily rotates at a high speed.

  Although the disk 3 is attached only to one side in the figure, it may be attached to both sides. As shown in FIG. 4, by attaching the disk 3 to the gear pump 18, the timing for communicating the suction port 14 side and the discharge port 15 side through the holes 8, 8. As the speed increases, the rotational speed of the gear pump 18 increases. However, by attaching the disk 3, an effect of suppressing the fluid discharge amount can be obtained, and energy loss can be suppressed.

DESCRIPTION OF SYMBOLS 1 Drive gear 2 Driven gear 3 Disk 4 Positioning member 5 Shaft 6 Shaft hole 7 Shaft hole 8 Hole 9 Groove hole
10 Coil spring
11 balls
12 groove
13 valley
14 Suction port
15 Discharge port
16 space
17 mountains
18 Gear pump
19 Torque converter
20 sleeve
21 Partition

Claims (3)

In a gear pump that can discharge the fluid sucked from the suction port by the meshing rotation of the drive gear having the tooth shape on the outer periphery and the driven gear having the tooth shape on the inner periphery, the one side of the drive gear. Alternatively, if the discs are mounted concentrically on both sides, and the same number of holes as the number of teeth of the drive gear are provided in the outer periphery of the disc, the rotational speed of the drive gear increases and exceeds a certain range. A gear pump with a torque limiter attached so that the phase changes due to relative rotation. The disk hole is in a state where the drive gear peak and the driven gear peak are in contact with each other at the boundary between the suction port side and the discharge port side when the disk rotates relative to the phase and is at the drive gear peak position. The gear pump according to claim 1, wherein the two tooth profile spaces communicate with each other through the hole. The torque limiter is provided with a slot in the radial direction from the inner periphery of the shaft hole of the disk, and a coil spring and a ball are fitted into the slot, and the ball is engaged by energizing a spring force in a groove formed on the shaft of the drive gear. The gear pump according to claim 1 or claim 2.

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