JP7637335B2 - Multiple gear pump or multiple gear motor - Google Patents

Description

The present invention relates to a multiple gear pump or multiple gear motor.

Various multiple gear pumps or multiple gear motors have been developed and disclosed in the past, including Patent Document 1 below. The multiple gear pump in Patent Document 1 below has a front stage and a rear stage. A drive gear and a driven gear are arranged in the front stage and the rear stage, respectively. The shafts of the drive gears in the front stage and the rear stage are connected by a mechanical connector. For example, when a multiple gear pump is used in construction machinery, the front stage may be used for rotating the cockpit and the rear stage for steering within the cockpit.

WO2014/191253A1 (Figure 12)

The multiple gear pump in Patent Document 1 has almost the same shape for the front and rear stages, making the multiple gear pump large in size. Since the size of the equipment in which the multiple gear pump is used also increases, it is desirable to reduce the size of the multiple gear pump. In addition, when the multiple gear pump is used in construction machinery, it is desirable to reduce noise inside the cockpit of the construction machinery by reducing vibrations caused by the discharge of hydraulic fluid in the rear stage used for steering.

The object of the present invention is to provide a multiple gear pump or multiple gear motor that is compact and reduces vibration caused by the discharge of hydraulic fluid.

To solve the above problems, the multiple gear pump or multiple gear motor of the present invention has the following configuration.

The multiple gear pump or multiple gear motor of the present invention includes a casing, a first gear storage chamber formed in the casing, a second gear storage chamber formed in the casing, a first drive gear arranged in the first gear storage chamber, a drive shaft rotatably supporting the first drive gear, a first driven gear arranged in the first gear storage chamber, meshed with the first drive gear and rotated by the first drive gear, a driven shaft rotatably supporting the first driven gear, n (n is an integer of 2 or more) drive gears attached to the drive shaft and arranged in the second gear storage chamber, and n driven gears attached to the driven shaft, arranged in the second gear storage chamber, meshed with the n drive gears arranged in the second gear storage chamber, and rotated by the n drive gears.

According to the present invention, the driving gear and driven gear in the second gear housing do not have a rotating shaft, so the external dimensions of the multiple gear pump or multiple gear motor are unlikely to become large. The teeth of the driving gear in the second gear housing are shifted at equal intervals, and the teeth of the driven gear in the second gear housing are shifted at equal intervals, so the discharge of the working fluid is shifted by half a period, which reduces the pressure pulsation of the combined working fluid and reduces the vibration of the multiple gear pump or multiple gear motor.

FIG. 1 is a diagram showing a configuration of a multiple gear pump of the present application. FIG. 4 is a diagram showing a second driving gear and a second driven gear. 4 is a diagram showing the positional relationship between the teeth of a second drive gear and the teeth of a third drive gear. FIG. FIG. 2 is a diagram showing the rear where the driven shaft is located and its surroundings. FIG. 13 is another view showing the rear where the driven shaft is located and its surroundings. 10 is a graph showing the pressure of the hydraulic fluid in the second discharge path, the pressure of the hydraulic fluid in the third discharge path, and a combined pressure of these pressures.

Embodiments of the present invention will be described with reference to the drawings. In multiple embodiments, identical parts will be designated by the same reference numerals and descriptions thereof may be omitted.

[Embodiment 1]
A multiple gear pump 10 of the present application shown in FIG. 1 includes gears 12, 14, shafts 16, 18 which rotatably support the gears 12, 14, and a casing 20 in which the gears 12, 14 and the shafts 16, 18 are housed.

The gears are made up of a pair of a first drive gear 12 and a first driven gear 14. Each gear 12, 14 has multiple teeth arranged at equal intervals. The teeth and tooth spaces of each gear 12, 14 are of the same shape. The first drive gear 12 and the first driven gear 14 mesh with each other, and as the first drive gear 12 rotates, the first driven gear 14 also rotates.

A drive shaft 16 is formed integrally with the first drive gear 12. The drive shaft 16 is disposed perpendicular to the side surface 22 from the center of the side surface 22 of the first drive gear 12. A driven shaft 18 is formed integrally with the first driven gear 14. The driven shaft 18 is disposed perpendicular to the side surface 24 from the center of the side surface 24 of the first driven gear 14.

The casing 20 includes a body 26, a front 28, and a rear 30. The body 26, the front 28, and the rear 30 have holes into which fasteners such as bolts are inserted. The body 26, the front 28, and the rear 30 are fixed together by fasteners such as bolts.

A first gear storage chamber 32 is formed inside the body 26. The first drive gear 12 and the first driven gear 14 are stored in the first gear storage chamber 32. The first gear storage chamber 32 is closed by the front 28. A bearing hole 34 is formed in the body 26 and the front 28, and the bearing hole 34 is connected to the first gear storage chamber 32. The drive shaft 16 and the driven shaft 18 are passed through the bearing hole 34 via a bush 36. The drive shaft 16 is rotated by a motor.

The first side plate 38 is disposed in contact with the side surfaces 22, 24 of the gears 12, 14. The first side plate 38 is a plate body with good sliding properties. The gears 12, 14 rotate with their side surfaces 22, 24 in contact with the first side plate 38.

A first suction passage (not shown) and a first discharge passage (not shown) are formed in the casing 20. The first suction passage and the first discharge passage are connected to the first gear housing chamber 32. Working fluid (hydraulic oil) is sucked into the first gear housing chamber 32 from the first suction passage, and the working fluid is discharged from the first gear housing chamber 32 through the first discharge passage. When the drive shaft 16 is rotated, the first drive gear 12 and the first driven gear 14 rotate, and the working fluid flows from the first suction passage to the first discharge passage.

A second gear housing 40 is formed in the rear 30 of the casing 20. The second gear housing 40 is connected to a bearing hole 34 between the first gear housing 32 and the second gear housing 40. The drive shaft 16 and the driven shaft 18 extend into the second gear housing 40. The first gear housing 32 and the second gear housing 40 may be formed in any of the body 26, the front 28, and the rear 30.

The second gear storage chamber 40 houses a second drive gear 42, a second driven gear 44, a third drive gear 46, and a third driven gear 48. Each of the gears 42, 44, 46, and 48 has multiple teeth arranged at equal intervals. The teeth and tooth spaces of each of the gears 42, 44, 46, and 48 are of the same shape.

The second drive gear 42 and the second driven gear 44 mesh together, and as the second drive gear 42 rotates, the second driven gear 44 also rotates. Furthermore, the third drive gear 46 and the third driven gear 48 mesh together, and as the third drive gear 46 rotates, the third driven gear 48 also rotates.

The second drive gear 42 has a through hole 50 in the center, through which the drive shaft 16 passes (Figure 2). Similarly, the third drive gear 46 has a through hole in the center, through which the drive shaft 16 passes. The inner surfaces of the second and third drive gears 42, 46 that form the through hole 50 are in contact with the outer surface of the drive shaft 16. An uneven portion 52 is formed on the outer surface of the drive shaft 16. The uneven portion 52 is uneven in the circumferential direction of the drive shaft 16. The inner surfaces of the second and third drive gears 42, 46 that form the through hole 50 are formed with an uneven portion 54 so that they can be fitted into the uneven portion 52. The uneven portions 52, 54 can be formed by spline processing on the outer surface of the drive shaft 16 and the inner surfaces of the second and third drive gears 42, 46 that form the through hole 50. When the drive shaft 16 rotates, the second and third drive gears 42, 46 rotate in accordance with the rotation. Although the shape of the uneven portions 52 and 54 shown in FIG. 2 is rectangular, the shape of the uneven portions 52 and 54 is not limited.

The second driven gear 44 has a through hole 56 in the center, through which the driven shaft 18 passes (FIG. 2). Similarly, the third driven gear 48 has a through hole in the center, through which the driven shaft 18 passes. The cross section of the driven shaft 18 perpendicular to its axial direction is a perfect circle. The through holes 56 of the second and third driven gears 44, 48 are shaped like a perfect circle, and the inner surfaces 58 of the second and third driven gears 44, 48 that form the through holes 56 are in contact with the outer surface 60 of the driven shaft 18. The second and third driven gears 44, 48 are not fixed to the driven shaft 18. The second and third drive gears 42, 46 rotate, so that the second and third driven gears 44, 48 can rotate independently of the rotation of the driven shaft 16. The central axis of the rotation is the center of the through hole 56, and the center coincides with the central axis of the driven shaft 16.

Since the second driven gear 44 and the third driven gear 48 are not fixed to the driven shaft 18, the gears 42, 44, 46, and 48 can rotate even if the dimensional accuracy of the shapes of the second driving gear 42, the second driven gear 44, the third driving gear 46, and the third driven gear 48 is somewhat reduced. When the gears 42, 44, 46, and 48 rotate, they are less likely to get stuck, so the gears 42, 44, 46, and 48 are less likely to be damaged.

The rotation shafts of the second drive gear 42, the second driven gear 44, the third drive gear 46 and the third driven gear 46 utilize the drive shaft 16 integrated with the first drive gear 12 and the driven shaft 18 integrated with the first driven gear 14, and do not have their own drive shaft or driven shaft. There is no need for the mechanical connectors described in the prior art. The multiple gear pump 10 is less likely to become large, making it easier to prevent the device that uses the multiple gear pump 10 from becoming large.

A second side plate 62 is disposed between the inner wall forming the second gear storage chamber 40 and the second drive gear 42 and second driven gear 44, and between the inner wall forming the second gear storage chamber 40 and the third drive gear 46 and third driven gear 48. The second side plate 62 is a plate body with good sliding properties, similar to the first side plate 38 disposed in the first gear storage chamber 32. One side of the second drive gear 42, second driven gear 44, third drive gear 46, and third driven gear 48 rotates while contacting the second side plate 62.

A third side plate 64 is disposed between the second driving gear 42 and the third driving gear 46 and between the second driven gear 44 and the third driven gear 48. The third side plate 64 is also a plate body with good sliding properties like the side plates 38 and 62. The other side surfaces (the surface opposite to the one side surface) of the second driving gear 42, the second driven gear 44, the third driving gear 46 and the third driven gear 48 rotate while contacting the third side plate 64.

In the second gear storage chamber 40, an area 66 for arranging the second drive gear 42 and the second driven gear 44 and an area 68 for arranging the third drive gear 46 and the third driven gear 48 are formed between the second side plate 62 and the third side plate 64.

When the second drive gear 42 and the third drive gear 46 are viewed in the longitudinal direction of the drive shaft 16, the center of the tooth 70 of the second drive gear 42 is located at the center of the tooth groove 72 of the third drive gear 46, and the center of the tooth 74 of the third drive gear 46 is located at the center of the tooth groove 76 of the second drive gear 42 (Figure 3). In other words, the second drive gear 42 and the third drive gear 46 are positioned with a half pitch (1/2 pitch) offset in the rotational direction of the drive shaft 16 (circumferential direction of the drive shaft 16).

When the second driven gear 44 and the third driven gear 48 are viewed in the longitudinal direction of the driven shaft 18, the center of the teeth of the second driven gear 44 is disposed at the center of the tooth groove of the third driven gear 48, and the center of the teeth of the third driven gear 48 is disposed at the center of the tooth groove of the second driven gear 44. In other words, the second driven gear 44 and the third driven gear 48 are disposed with a half-pitch offset in the rotational direction of the driven shaft 18 (circumferential direction of the driven shaft 16).

A second intake passage 80 for supplying hydraulic fluid to the area 66 where the second drive gear 42 and the second driven gear 44 are arranged, and a second discharge passage 82 for discharging hydraulic fluid from the area 66 where the second drive gear 42 and the second driven gear 44 are arranged are formed in the rear 30 of the casing 20 (Figure 4). These passages are cavities formed in the casing 20. The second intake passage 80 and the second discharge passage 82 are connected to the area 66.

A third suction passage 84 for supplying hydraulic fluid to the region 68 in which the third drive gear 46 and the third driven gear 48 are arranged, and a third discharge passage 86 for discharging hydraulic fluid from the region 68 in which the third drive gear 46 and the third driven gear 48 are arranged are formed in the casing 20 (Figure 4). These passages are cavities formed in the casing 20. The third suction passage 84 and the third discharge passage 86 are connected to the region 68.

As shown in FIG. 4, the second suction passage 80 and the third suction passage 84 are separate passages formed in the casing 20. Also, as shown in FIG. 5, the second suction passage 80 and the third suction passage 84 may be a single passage 90 outside the casing 20, and may branch into the respective suction passages 80, 84 inside the casing 20.

As shown in FIG. 4, the second discharge passage 82 and the third discharge passage 86 are separate passages formed in the casing 20. Also, as shown in FIG. 5, the second discharge passage 82 and the third discharge passage 86 may merge inside the casing 20 to form a single passage 92. Furthermore, even if the second discharge passage 82 and the third discharge passage 86 do not merge inside the casing 20, a passage for the working fluid may be formed so that the working fluids in the respective passages 82, 86 merge outside the casing 20.

The pressure Pa when the working fluid is discharged by the second driving gear 42 and the second driven gear 44 and the pressure Pb when the working fluid is discharged by the third driving gear 46 and the third driven gear 48 are pulsating (Figure 6). Furthermore, the second driving gear 42 and the third driving gear 46 are shifted by half a pitch, and the second driven gear 44 and the third driven gear 48 are shifted by half a pitch. Therefore, when the pressure Pa when the working fluid is discharged by the second driving gear 42 and the second driven gear 44 increases, the pressure Pb when the working fluid is discharged by the third driving gear 46 and the third driven gear 48 decreases. Conversely, when the pressure Pb when the working fluid is discharged by the third driving gear 46 and the third driven gear 48 increases, the pressure Pa when the working fluid is discharged by the second driving gear 42 and the second driven gear 44 decreases.

When the hydraulic fluid in the second discharge passage 82 and the third discharge passage 86 are joined, the hydraulic fluid pressures Pa and Pb are combined, and pulsation is reduced, as shown by pressure P in FIG. 6. Vibrations caused when the hydraulic fluid is discharged by the second drive gear 42, the second driven gear 44, the third drive gear 46, and the third driven gear 48 are suppressed. When the second drive gear 42, the second driven gear 44, the third drive gear 46, and the third driven gear 48 are used for steering the cockpit of a construction machine, vibrations in the cockpit can be suppressed.

As described above, the present application does not provide shafts for the second drive gear 42, the second driven gear 44, the third drive gear 46, and the third driven gear 48, so the size of the multiple gear pump 10 is unlikely to increase. By shifting the teeth or tooth grooves of the second drive gear 42 and the third drive gear 46, and the second driven gear 44 and the third driven gear 46 by half a pitch, the pulsation of the working fluid discharged from the second discharge passage 82 and the third discharge passage 86 is reduced, and vibration can be reduced.

[Embodiment 2]
To generalize the above embodiment, in the multiple gear pump 10 according to the preferred embodiment of the present invention, the numbers of the drive gears 42, 46 and the driven gears 44, 48 arranged in the second gear housing 40 are arbitrary as long as they are 2 or more. Hereinafter, the numbers of the drive gears and the driven gears arranged in the second gear housing 40 are each assumed to be n, where n is an integer of 2 or more.

The first drive gear 12 and the first driven gear 14 are arranged in the first gear storage chamber 32. The configuration is the same as that described in the first embodiment above. The n drive gears and the n driven gears are arranged in the second gear storage chamber 40. The configuration of these drive gears and driven gears is the same as that of the second drive gear 42, the second driven gear 44, the third drive gear 46, and the third driven gear 48 described in the first embodiment above. The drive gear arranged in the second gear storage chamber 40 has a through hole 50 with a concave-convex portion 54 formed therein, and the driven gear has a circular through hole 56 formed therein. The drive shaft 16 passes through the through hole 50, and the driven shaft 18 passes through the through hole 56.

The teeth of the n driving gears arranged in the second gear storage chamber 40 are offset by 1/n pitch in the circumferential direction of the drive shaft 16, and are arranged so that the teeth and tooth grooves are equally spaced. Similarly, the teeth of the n driven gears arranged in the second gear storage chamber 40 are offset by 1/n pitch in the circumferential direction of the driven shaft 18, and are arranged so that the teeth and tooth grooves are equally spaced. By offsetting the positions of the teeth and tooth grooves as described above, it is possible to reduce pulsation of the working fluid.

A third side plate 64 is provided between the drive gears and between the driven gears in the second gear storage chamber 40. Each gear is arranged in an area partitioned by the third side plate 64. Furthermore, a second side plate 62 is arranged on the inner wall of the second gear storage chamber 40. The drive gear and driven gear arranged at the extreme ends of the second gear storage chamber 40 are also in contact with the second side plate 62. Suction passages and discharge passages are individually connected to the areas where each gear is arranged, and the working fluid is sucked into those areas and discharged from those areas. Also, as shown in FIG. 5, a single passage 90 may branch into multiple suction passages, or multiple discharge passages may merge into a single passage 92.

[Embodiment 3]
The multiple gear motor of the present application can be configured in the same structure as the multiple gear pump 10 described in the above embodiment.

(1) A multiple gear pump 10 or multiple gear motor according to one embodiment of the present application includes a casing 20, a first gear storage chamber 32 formed in the casing 20, a second gear storage chamber 40 formed in the casing 20, a first drive gear 12 arranged in the first gear storage chamber 32, a drive shaft 16 rotatably supporting the first drive gear 12, a first driven gear 14 arranged in the first gear storage chamber 32, meshing with the first drive gear 12 and rotated by the first drive gear 12, a driven shaft 18 rotatably supporting the first driven gear 14, n (n is an integer of 2 or more) drive gears attached to the drive shaft 16 and arranged in the second gear storage chamber 40, and n driven gears attached to the driven shaft 18, arranged in the second gear storage chamber 40, meshing with the n drive gears arranged in the second gear storage chamber 40, and rotated by the n drive gears.

According to the multiple gear pump 10 or multiple gear motor described in paragraph 1, the multiple drive gears and driven gears arranged in the second gear storage chamber 40 do not have their own rotating shafts, but are supported by the drive shaft 16 of the first drive gear 12 and the driven shaft 18 of the first driven gear 14, so that the external dimensions of the multiple gear pump 10 or multiple gear motor are smaller than those of the conventional multiple gear pump 10 or multiple gear motor.

(2) When the n driving gears in the second gear storage chamber 40 are viewed from the longitudinal direction of the drive shaft 16, the teeth of the n driving gears in the second gear storage chamber 40 are shifted from each other by 1/n pitch, and when the n driven gears in the second gear storage chamber 40 are viewed from the longitudinal direction of the driven shaft 18, the teeth of the n driven gears in the second gear storage chamber 40 are shifted from each other by 1/n pitch.

According to the multiple gear pump 10 or multiple gear motor described in paragraph 2, by shifting the pitch of each gear arranged in the second gear storage chamber 40 at equal intervals, when the working fluid discharged from each gear is joined, the amplitude of the pulsation of the working fluid generated by each gear is offset, so that the amplitude of the pulsation of the working fluid that is joined and discharged by each gear can be reduced.

(3) An uneven portion 52 is formed on the outer surface of the drive shaft 16, and a through hole 50 that fits into the uneven portion 52 is formed in the center of the n drive gears in the second gear storage chamber 40.

According to the multiple gear pump 10 or multiple gear motor described in paragraph 3, the uneven portion 52 is formed on the outer surface of the drive shaft 16, so that the drive gear arranged in the second gear storage chamber 40 can rotate in accordance with the rotation of the drive shaft 16 without increasing the size of the entire device.

(4) A through hole 56 is formed in the center of the n driven gears in the second gear storage chamber 40, and a driven shaft 18 having a circular cross section is inserted through the n driven gears in the second gear storage chamber 40 without being fixed thereto.

According to the multiple gear pump 10 or multiple gear motor described in paragraph 4, the driven gears in the second gear housing 40 are not fixed to the driven shaft 18, so even if there is some error in the dimensions of each gear arranged in the second gear housing 40, those gears can rotate.

(5) The second gear storage chamber 40 includes side plates 64 arranged between two adjacent drive gears among the n drive gears, and between two adjacent driven gears among the n driven gears in the second gear storage chamber 40.

According to the multiple gear pump 10 or multiple gear motor described in paragraph 5, the area in which the drive gear and driven gear are arranged is divided by the side plate 64, and the working fluid can be sucked in and discharged by each gear.

In addition, the present invention can be implemented in various forms with various improvements, modifications, and changes based on the knowledge of those skilled in the art without departing from the spirit of the invention.

10: multiple gear pump 12, 14, 42, 44, 46, 48: gear 16: drive shaft 18: driven shaft 20: casing 26: body 28: front 30: rear 32, 40: gear storage chamber 34: casing through hole 36: bushing 38, 62, 64: side plate 50, 56: gear through hole 52, 54: uneven portion 58: inner surface of driven gear 60: outer surface of driven shaft 66, 68: area where gear is arranged 70, 74: teeth 72, 76: tooth groove 80, 84: suction passage 82, 86: discharge passage

Claims (5)

A casing;
a first gear housing formed in the casing;
a second gear housing formed in the casing;
A first drive gear disposed in the first gear housing;
a drive shaft that rotatably supports the first drive gear;
a first driven gear disposed in the first wheel housing, meshing with the first drive gear and rotated by the first drive gear;
a driven shaft that rotatably supports the first driven gear;
n (n is an integer of 2 or more) drive gears attached to the drive shaft and disposed in the second gear housing;
n driven gears attached to the driven shaft, disposed in the second gear housing, meshed with the n driving gears disposed in the second gear housing, and rotated by the n driving gears;
A multiple gear pump or multiple gear motor comprising:
The n driving gears are spaced apart from one another in the longitudinal direction of the drive shaft,
A multiple-gear pump or multiple-gear motor, wherein the n driven gears are arranged at intervals from one another in the longitudinal direction of the driven shaft . When the n driving gears in the second gear housing are viewed from the longitudinal direction of the drive shaft, the teeth of the n driving gears in the second gear housing are shifted from each other by 1/n pitch,
2. The multiple-gear pump or multiple-gear motor of claim 1, wherein, when the n driven gears in the second gear housing are viewed from the longitudinal direction of the driven shaft, the teeth of the n driven gears in the second gear housing are shifted from each other by 1/n pitch. The outer surface of the drive shaft is formed with projections and recesses,
A through hole that fits into the concave and convex portion is formed at the center of the n driving gears in the second gear storage chamber.
3. A multiple gear pump or multiple gear motor according to claim 1 or 2. A through hole is formed at the center of the n driven gears in the second gear housing,
4. The multiple-gear pump or multiple-gear motor according to claim 1, wherein a driven shaft having a circular cross section is inserted through the n driven gears in the second gear housing chamber without being fixed thereto. A multiple gear pump or multiple gear motor according to any one of claims 1 to 4, including side plates arranged between two adjacent drive gears among the n drive gears in the second gear storage chamber, and between two adjacent driven gears among the n driven gears in the second gear storage chamber.

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