JPH112190A - Rotary displacement type hydraulic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress noise generated in operation. SOLUTION: First gears 24, 27 and second gears 25, 28 are rotatably installed on two actuation chambers 11, 12 provided on a housing 10, and the first gear and the second gear in each actuation chamber 11, 12 are installed in such a way that their tooth phases are mutually deflected by 1/4 pitch, and that teeth of one gear of two gears in each engaged gear set are simultaneously engaged with flanks of two adjacent teeth of the other gear along two parallel contact lines.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary positive displacement hydraulic device such as a gear pump and a gear motor.

[0002]

BACKGROUND OF THE INVENTION A rotary positive displacement hydraulic device in the form of a gear pump or gear motor generally comprises two actuating, axially extending, communicating parts that are mutually parallel. It has a housing with chambers and two sets of meshing gears rotatably mounted on each chamber about an axis for pumping fluid from an inlet to an outlet.

[0003]

The source flow characteristics of the outer involute gear pump and the gear motor determine the generation of fluid-borne noise in such devices and the air-borne noise from the hydraulic systems used in these devices. Is the main cause.

In general, devices that generate the lowest number of frequencies yield the quietest systems. Gear pumps and prime movers are characterized by the noise of the first four harmonics of the gear tooth frequency. That is, the first harmonic, the second harmonic having 1/4 the amplitude of the first harmonic, the third harmonic having 1/9 the amplitude of the first harmonic, and the first harmonic.
It is characterized by a fourth harmonic having 1/16 of the amplitude of the harmonic.

In each working chamber, there are two identical gears separated from each other by a center plate,
Each gear in each chamber forms a meshing set with a corresponding gear in the other chamber, the gears in each gear set make a single flank contact (with backlash), and two gears in each chamber. Gear pumps or prime movers are known in which the teeth are out of phase with each other (corresponding to a 180 ° phase shift at the first harmonic frequency).

[0006] Such a structure produces a distribution variation at twice the tooth frequency by eliminating odd harmonic frequency components that would otherwise occur. The noise output of such a device is therefore the first (which would otherwise occur).
A second harmonic frequency component of 1/4 of the amplitude of the harmonic component;
And a fourth harmonic frequency component that is 1/16 of the amplitude of the harmonic component.

As an alternative to such a structure, it is known to use a double flank contact meshing gear (without backlash), in which each tooth of each meshing gear has two adjacent teeth of the other meshing gear. Engages simultaneously with the flank along two parallel contact lines,
Dispersion fluctuations occur at twice the frequency of the teeth and at 1/4 of the amplitude of the single flank backlash contact structure.
That is, a flow fluctuation having a harmonic component similar to that of the above-described structure occurs.

Although both of the above structures have been used separately to form low noise gear pumps and gear prime movers, low noise gear pumps and gear prime movers can still produce significant noise in some conditions. is there.

It is an object of the present invention to provide a low noise gear pump or prime mover.

[0010]

SUMMARY OF THE INVENTION In accordance with the present invention, a housing containing two working chambers extending axially with axes parallel to each other, and each chamber having an axially extending axis for fluid pumping. A first gear and a second gear rotatably mounted, wherein each gear in each chamber forms a meshing set with a respective one gear in the other chamber, and the first gear and the second gear in each chamber are engaged. The teeth are mounted out of phase with each other by about 1/4 pitch,
Characterized in that the teeth of one of the two gears of each meshing gear set mesh with the flanks of two adjacent teeth of the other gear so as to simultaneously engage along two parallel contact lines. A rotary positive displacement hydraulic device in the form of a gear pump or gear motor is provided.

The teeth of the first and second gears have exactly one tooth pitch corresponding to a 90 ° phase shift at the first harmonic frequency.
Ideally, a phase shift of / 4 would be ideal, but it should be understood that manufacturing tolerances will cause this phase shift to vary from the ideal value, for example in the range of 80 to 100 degrees.

The effect of adjusting the phase of the two gears in each chamber so that the gear teeth are out of phase by about 1/4 pitch is due to the double flank contact of the meshing gear (no backlash contact) resulting in the original odd frequency component. The odd harmonic frequency components remaining after the removal of the first harmonic component are substantially removed, and only the fourth harmonic frequency component having 1/16 of the amplitude of the first harmonic component may remain. Such a structure allows for hydraulic transmission in the first three harmonics of the tooth frequency with substantially no noise of fluid origin.

The present invention also provides a housing having two working chambers extending axially with axes parallel to each other, and rotatably mounted about each axis within each chamber to provide fluid pumping. 1st gear and 2nd gear
And each gear of each chamber forms an intermeshed set with a respective gear of the other chamber, and the teeth of the first and second gears of each chamber are mutually in phase by about 1/4 pitch. A rotary positive displacement hydraulic device in the form of a gear pump or a gear motor, wherein the first and second gears of the other chamber are separately rotatably supported by respective bearings while being mounted on a common shaft while being shifted. I will provide a.

[0014]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a double flank contact device. In this double flank contact device, the two meshing gears 2, 3 of the gear pump are engaged with each other and the teeth 4 of one gear are connected to the flank 5, 6 of two adjacent teeth 5, 6 of the other gear. On the other hand, simultaneous contact is made along two parallel contact lines 7, 8 extending parallel to the gear axis. The double flank contact device (without backlash) is twice the tooth frequency of the single flank contact device (with backlash),
A distribution change occurs at 1/4 of the amplitude. As a result, it is possible to eliminate an odd harmonic component which is generated when using the single type flank contact device.

FIGS. 2 and 3 show a gear pump 1 having a pot-shaped body formed from cast iron. The gear pump 1 has a housing 10 including a pot body 13 and an end cover 14 fastened to the pot body 13 by bolts 19. Two meshing pump rotor 1
5 and 16 are provided with axes 17, 1 in two mutually intersecting working chambers 11, 12 formed in a body 13.
It is mounted so that it can rotate around eight. Each rotor has sleeve bearings 20, 2 received on body 13 and end cover 14.
1, respectively.

The pump rotor 16 has a hole 23 in the cover 13.
And a first and second gear 24, 25 attached to the drive shaft 22. Further, the pump rotor 15 has a driven shaft 26 and first and second gears 27 and 28 attached to the driven shaft 26. The body 10 forms a low pressure or inlet port 29 and a high pressure or outlet port 30 at its closed end, each port communicating with a working chamber 11 and 12, respectively.

The first of each of the two rotors 15 and 16
Gears 24 and 27 engage in double flank contact mesh engagement (no backslash), and their respective second gears 25 and 28 also form a similar double flank engagement. Also, each second gear 25
And 28 are respectively the corresponding drive shaft 22 or driven shaft 26
The first gear 24 is attached to the shaft 22 by a key 31, and has a specific phase relationship with the second gear 25 on the same shaft. In this case, the teeth of these two gears are out of phase with each other by ４ of the tooth pitch, and the first gear 27 is rotatable about the shaft 26. Each gear set, 24, 25 or 27, 28 has two pressure balance plates 32 and 33, respectively.
Between each gear set are separated from each other by a center plate 34, which separately holds the fluid flow pumped by the two gears. First gears 24 and 27 on shafts 22 and 26 are mounted for axial movement and engage hydraulically with center plate 34 to provide a seal between the two pumping streams.

The gear pump with the compound gear arrangement with such balancing plate and compound flank contact allows hydraulic transmission with substantially no fluid noise in the first three harmonics of the tooth frequency, so that the gear pump operates. Especially quiet inside.

In addition, a similar structure can be applied to the conventional type gear pump 40 shown in FIG. 4, in which the housing 41 has a generally cylindrical body 42, which has opposite ends. Are provided with two end covers 43 and 44 for closing the chamber, and aluminum bushings 45 and 46 for defining both ends of each chamber 11 or 12 inside the main body. This construction is otherwise similar to the pump having the pot-shaped body shown in FIG. 2, and similar parts are indicated by similar reference numerals.

FIG. 5 shows a tandem structure 50 in which a pump having two pot-like bodies is arranged back to back and has a common housing 51 formed from a single cast iron body 52, Both ends cover 53 and 54
And has two differently sized pump sections on a common drive shaft 55. Each section includes a respective single gear 56 or 57 mounted in a particular phase relationship on the drive shaft 55, and meshes with these gears 56 or 57 to form a second integral with the respective driven shafts 60 and 61.
Includes gear 58 or 59. Each gear 56, 57, 58,
59 is held between the corresponding balancing plates 62 and 63 with a small degree of axial freedom, and the gear 57 is arranged by a key 64 on the shaft 55 to allow relative axial movement in the gears 56 and 57. The phase relationship between the gear sets 56, 57 is precisely controlled by its mounting on the common shaft 55, each of which is controlled such that the gear teeth are 1/4 pitch out of phase with each other. Such a phase structure reduces the amplitude of odd frequency harmonics, such as would occur when combining the outputs of two pump sections without such a phase relationship (or where the two pump sections are of the same size). In some cases, such harmonics are completely eliminated), and when the drive shaft consists of two parts for the two pump sections and these parts need to be interconnected by interengaging splines, this spline is removed. The need for accurate positioning can be avoided. Such tandem arrangements may each have separate or interconnected inlets and outlets, and the pump (or prime mover) may be single or dual rotation.

The tandem structure 65 shown in FIG. 6 is similar to the structure shown in FIG. 5, but differs from the structure shown in FIG.
The first and second gears 66, 67 having a phase shift of the following are provided on the drive shaft 55 in each pump section, and a center plate 68 is disposed between the first and second gears 66, 67 in each section, The first and second gears 6
6, 67 are mounted on driven shafts 60 or 61, respectively, and are separated by a center plate 71.
And a double flank contact meshing engagement with the second gears 69, 70. A common drive shaft 55 controls the phase relationship between the first and second gears 66 and 67 of each pump section and the phase relationship between the gears of both pump sections, and the key 72 on shaft 55 The attachment of three of the gears allows relative axial movement between the gears and provides a fluid seal between the separate fluid streams of each gear. The combination of the phase relationship of the first and second gears 66, 67 and the double flank contact structure allows the first three frequency adjustments of the tooth frequency in each pump section in a manner similar to that described for the embodiment of FIGS. Waves can be eliminated. Further, if the outputs of the two pump sections are combined, the phase of the first and second gears 66, 67 in one section will be the first in the other pump section.
Of the tooth pitch with respect to the phase of the
If shifted by / 8, the fourth frequency harmonic is also removed, and the eighth frequency harmonic remains as the lowest harmonic.

The pump structure 74 shown in FIG. 7 has a cylindrical body 42 and end cover 4 generally similar to the embodiment of FIG.
3 and 44, with the difference that the two pump sections comprise gears 56 and 57 mounted on a common drive shaft 55, the gears 56 and 57 of which the teeth are 1/1 relative to each other. The gears 56, 57 are arranged in a specific phase relationship such that they are out of phase by four pitches, and these gears 56, 57 are mounted on respective drive shafts 60 and 61.
Engage with 8,59. Each gear is held between a respective bushing 45 and 46, and both pump sections are optionally separated from one another by a separating plate 76. In this embodiment, the inlet and outlet of both pump sections are combined, and the particular phase relationship of both pump sections creates odd frequency harmonics that would otherwise occur without such a phase relationship. Can be removed.

[Brief description of the drawings]

FIG. 1 shows a double flank contact device.

FIG. 2 shows a first embodiment of a gear pump according to the invention, FIG.
FIG. 2 is an axial sectional view taken along line II-II of FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is an axial sectional view of a second embodiment of the gear pump according to the present invention.

FIG. 5 is an axial sectional view of a third embodiment of the gear pump according to the present invention.

FIG. 6 is an axial sectional view of a fourth embodiment of the gear pump according to the present invention.

FIG. 7 is an axial sectional view of a fifth embodiment of the gear pump according to the present invention.

[Description of Signs] 2, 3 Meshing gear 4, 5, 6 Teeth 7, 8 Contact surface 10 Housing 11, 12 Working chamber 22, 26, 55 Common shaft 24, 27, 56, 58, 66, 69 First gear 25 , 28, 57, 59, 67, 70 Second gear 34, 68, 76 Center plate 45, 46 Bushing

Claims (11)

[Claims] 1. A housing (10) containing two working chambers (11, 12) extending axially with axes parallel to each other and an axis around each of the chambers to provide fluid pumping. A first gear (24, 27) and a second gear (25, 28) rotatably mounted, wherein each gear of each working chamber meshes with a respective one gear of the other working chamber; Of the first and second gears are mounted out of phase with each other by about 1/4 pitch, with each tooth of one of the two gears of each meshing gear set being two adjacent teeth of the other gear. A rotary positive displacement hydraulic device in the form of a gear pump or a gear motor, which is intermeshing with the tooth flanks so as to engage simultaneously along two parallel contact lines. 2. A first gear and a second gear of one working chamber.
Gears (24 and 25; 56 and 57; 66 and 6)
7. The rotary positive displacement hydraulic device according to claim 1, wherein 7) is mounted on a common shaft (22, 55), and the teeth of these gears are mutually out of phase by about 1/4 of the tooth pitch. 3. The first and second gears (2) of the other chamber.
3. The rotary positive displacement hydraulic device according to claim 2, wherein the teeth of said 7, 28) are mounted on the common shaft (26) out of phase with each other by about 1/4 pitch. 4. The first and second gears (5) of the other chamber.
3. The rotary positive displacement hydraulic apparatus according to claim 2, wherein the bearings (8, 59) are separately rotatably supported by respective bearings. 5. A center plate (34, 68, 76) is arranged between the first and second gears of each chamber to separate the fluid flow pumped by these gears. The rotary positive displacement hydraulic device according to any one of claims 1 to 4. 6. The rotary positive displacement hydraulic apparatus according to claim 5, wherein at least one of the first gear and the second gear slides in the axial direction by fluid pressure and engages with the center plate. 7. A pump having two pump sections, each pump section having two sets of meshing gears (66, 67 and 69, 70), each set of two gears being located in a different working chamber; The teeth of the first and second gears of each chamber are mounted such that they are approximately 1/4 pitch out of phase with each other, such that each tooth of one of the two gears of each meshing gear set has two teeth of the other gear. The rotary positive displacement hydraulic device according to any one of claims 1 to 6, wherein the flank of the adjacent tooth is meshed with each other so as to be engaged simultaneously along two parallel contact lines to form a tandem structure. . 8. The first of one chamber of one of the pump sections.
8. The device according to claim 7, wherein the first and second gears of the first and second chambers of the other pump section are mounted on the common shaft in a specific phase relationship. Rotary displacement hydraulic system. 9. A method according to claim 1, wherein the working chamber is defined by two parallel intersecting holes formed in a one-piece body forming part of the housing. A rotary positive displacement hydraulic device according to claim 1. 10. The rotary displacement type according to claim 1, wherein the working chamber is defined by a bush (45, 46) inserted into a receiving recess formed in the housing. Hydraulic equipment. 11. A housing having two working chambers extending axially with axes parallel to each other, and a first gear rotatably mounted about each axis within each chamber to provide fluid pumping. (56, 58) and a second gear (57, 59), wherein each gear of each chamber forms an intermeshed set with a respective one gear of the other chamber, and a first gear and a second gear of each chamber. (56,
57) are mounted on a common shaft (55) out of phase with each other by about 1/4 pitch and the first in the other chamber.
A rotary positive displacement hydraulic device in the form of a gear pump or a gear motor, wherein a second gear (58, 59) is rotatably and separately supported by respective bearings.