JP2001182648A - Hydraulic pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce noise by hydraulic pressure fluctuation with a excellent follow-up in a small size, and to preclude the possibility of mixing of gas in oil in a hydraulic pump. SOLUTION: In this gear pump, a pair of driving gear 5 and driven gear 6 are arranged in a pump chamber 70, and a hydraulic fluid is sent out to a delivery chamber 72 from a suction chamber 71 by rotation of both gears 5, 6. This hydraulic pump is provided with a noise damper cylinder 20 having a capacity chamber 20a communicated with the delivery chamber 72, and is provided with a bottomed cylindrical elastomer member 32 having a peripheral wall part 33 and a bottom wall part 34 fixed in close contact to a peripheral wall surface 30 and a bottom wall surface 31 of the noise damper cylinder 20. The elastomer member 32 changes the volume to absorb the hydraulic pressure fluctuation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a gear pump and other hydraulic pumps.

[0002]

2. Description of the Related Art Conventionally, a gear pump has been used as a small and light pump having a simple structure in various industrial fields, such as a power steering device and an automatic transmission in an automobile. Have been. As a structure of this type of gear pump, a pair of side plates are fitted into a cavity inside the housing to define a pump chamber, and a pair of gears meshing with each other are housed inside the pump chamber. A low-pressure chamber for sucking hydraulic oil and a high-pressure chamber for discharging hydraulic oil were formed inside the pump chamber while being fitted and supported by support holes formed in the side plates, with the meshing positions of both gears interposed therebetween. Type is common.

On the other hand, in recent years, there has been a demand for a compact, high-rotation type gear pump having a high discharge pressure for the purpose of energy saving, but there is a possibility that noise due to a hydraulic shock or pulsation may increase due to an increase in speed. This type of problem exists not only in gear pumps but also in trochoid pumps and other hydraulic pumps. Therefore, an accumulator has been conventionally used. The accumulator has a gas chamber and a hydraulic chamber, and has a structure in which a piston and a diaphragm are provided on a partition that partitions the two chambers. However, in this accumulator,
In the event of a failure, gas will enter the oil in the hydraulic chamber. Also, it cannot follow a rapid change in oil pressure. further,
It is necessary to provide a gas chamber, and there is a problem that the structure becomes large.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a hydraulic pump which is small in size, can reduce noise due to fluctuations in hydraulic pressure with good followability, and has no risk of gas being mixed into oil.

[0005]

According to a first aspect of the present invention, there is provided a hydraulic pump including a noise damper cylinder communicating with a discharge chamber of a pump housing having a suction chamber and a discharge chamber. A bottomed cylindrical elastomer member substantially along the inner wall of the housing.

In this configuration, since the shock and the pulsation of the oil pressure fluctuation are absorbed by the volume change due to the elasticity of the elastomer member, the oil pressure fluctuation can be absorbed with good followability. Also, unlike the conventional accumulator, there is no need to provide a gas chamber, and the size can be reduced. Further, there is no possibility that gas is mixed into the oil unlike the conventional accumulator. In particular, since the elastomer member is provided inside the original noise damper tube, the structure is simple.In addition, since the elastomer member is formed into a bottomed tube substantially along the inner wall of the noise damper tube, it is possible to use a conventional space. However, a sufficient pressure receiving area can be secured. Therefore, it is possible to obtain a sufficient amount of volume change of the elastomer member even with a small oil pressure fluctuation, and from this point, it is possible to greatly improve the followability to the oil pressure fluctuation and to reliably absorb the oil pressure fluctuation. Can be.

According to a second aspect of the present invention, in the first aspect, the elastomer member is tightly fixed to an inner wall surface of the noise damper cylinder. With this configuration, the same operation and effect as the first aspect of the invention can be obtained. In addition, since the elastomer member is tightly fixed to the inner wall surface of the noise damper cylinder, the elastomer member does not hinder the air bleeding operation during assembly. According to a third aspect of the present invention, in the first or second aspect, an undulating shape for increasing a surface area is provided on an inner surface of the elastomer member. With this configuration, the same operation and effect as the operation and effect of the first or second aspect of the invention can be obtained. In addition, by further increasing the pressure receiving area, it is possible to further improve the responsiveness to hydraulic pressure fluctuations and to more reliably absorb the hydraulic pressure fluctuations. The undulating shape may be, for example, a pleated shape or a wart shape.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing the embodiments. 1 is a longitudinal sectional side view of a hydraulic pump according to one embodiment of the present invention, FIG. 2 is a sectional view from another angle, and FIG. 3 is a sectional view taken along line III-III in FIG. FIG. 4 is a sectional view taken along line IV-IV in FIG. The hydraulic pump A shown in FIGS. 1 to 4 is composed of an electric gear pump. Referring mainly to FIG. 2, the hydraulic pump A includes an electric motor 2 having a drive shaft 1 (motor shaft), and a driven shaft 4 (pump shaft) interlocked with the drive shaft 1 via a drive joint 3. And a driving gear 5 driven via the driven shaft 4, and a driven gear 6 meshing with the driving gear 5
And a pump housing 7 having a suction chamber 71 and a discharge chamber 72 (see FIG. 3) formed by meshing of the driving and driven gears 5 and 6, and first and second housings supporting the pump housing 7 from both sides. Supports 8, 9;
There is provided a bottomed cylindrical tank housing 10 that covers the outside of the second housing support 9 and the pump housing 7 in a state combined with the first housing support 8.

Referring to FIG. 1, a bottomed noise damper tube 20 is fitted and fixed in a fitted portion 93 formed in a cylindrical wall portion 7b of a pump housing 7. The noise damper cylinder 20 communicates with the discharge chamber 72 and the discharge chamber 7.
It has a capacity chamber 20a having a capacity larger than two.
The feature of this embodiment is that the noise damper cylinder 2
An elastomer member 32, such as a bottomed cylindrical rubber, along the peripheral wall surface 31 and the bottom wall surface 32, which is the inner wall of No. 0, is fixed by lining (lining), and pulsation and other hydraulic fluctuations can be effectively reduced by a simple structure. The point is to control.

The capacity chamber 20a is substantially partitioned by a bottomed cylindrical elastomer member 32. It is preferable that the elastomer member 32 has a closed cell foam structure in that the volume change can be increased. In order to line the elastomer member 32, for example, baking or bonding may be used. Referring to FIGS. 1, 2 and 3, pump housing 7 accommodates drive gear 5 and driven gear 6, and has a cylindrical body 7a having a pump chamber 70 as an elliptical gear chamber communicating with each other. And a pair of side plates 7b and 7c for closing both open portions of the pump chamber 70. The pump housing 7 includes these side plates 7
The drive gear 5 and the driven gear 6 are alternately meshed with the two sets of bearing holes 11 and 12 formed in the b and 7c via the driven shaft 4 and the driven shaft 51 parallel to the driven shaft 4. The suction chamber 71 and the discharge chamber 72 are formed on both sides of the meshing position so that the hydraulic oil sucked into the suction chamber 71 can be supplied between the teeth of the driving and driven gears 5 and 6. It is configured to perform a pumping action of receiving and sealing between the inner peripheral surface of the pump chamber 70 and the pump chamber 70 and sending out the same to the discharge chamber 72. In FIG. 1, 49 and 50 are each side plate 7.
b, 7c and a sealing member for sealing between the corresponding plate walls 9a, 8a of the supports 9, 8.

A suction port 73 opening to the pump chamber 70 is provided at one portion of the body portion 7a, a second discharge oil passage 74 penetrating in the axial direction on the opposite side, and a side plate 7b is provided at one side plate 7b. A first discharge oil passage 75 having a discharge port opening to the discharge chamber 72 is provided. First suction pipe 29 communicating with tank housing 10 which is the suction port destination
And a rubber silencer 80 extending upward along the inner peripheral surface of the low-pressure chamber described later is connected between the L-shaped second suction pipe 27 forming the suction port 73 and the drive and driven gear. The sound generated when the pressure oil sealed between the pair of meshing teeth 5, 6 is returned to the suction chamber 71 can be suppressed. A suction oil passage 35 is formed by the first suction pipe 29, the silencing pipe 80, and the second suction pipe 27.

The discharge oil passage 36 is formed in the first discharge oil passage 75, the first communication hole 91, the capacity chamber 20a, the second communication hole 92, and the body 7a of the pump housing 7 formed in the side plate 7b. And a third discharge oil passage 81 formed in the first housing support member 8 and opened at the connection port 37. The above connection port 37
Is a connection port connected to an external discharge destination, for example, a power steering device. A first housing support 8 supporting the pump housing 7 is detachably attached to the motor housing of the electric motor 2, and a second housing support 9 is provided on an outer surface of the body portion 7a as shown in FIG. The pump housing 7 is detachably attached to the plate wall portion 8a of the first housing support 8 via four fixing bolts 40 disposed along the same. I am trying to do it.

The second housing support 9 is provided with a first communication hole 91 communicating with the first discharge oil passage 75 and the first communication hole 9.
A plate wall portion 9a having a second communication hole 92 drilled in parallel with the first housing member 1 and in contact with one axial end of the pump housing 7;
A cylindrical wall portion 9b connected to an outer peripheral portion of the plate wall portion 9a; and a fitting portion 93 to which a fitting fixing portion 23 to be described later is screw-fitted is formed on an inner periphery of the open end side of the cylindrical wall portion 9b. Provided,
The female thread of the fitted portion 93 communicates with the discharge chamber 72 via a first discharge oil passage 75, and a bottomed noise damper cylinder 20 having a capacity chamber 20a having a larger volume than the discharge chamber 72 is detachable. Attached to.

The cylinder wall 9b has a length that can be inserted from the open end of the noise damper cylinder 20 to the bottom thereof.
The seal body 13 is interposed between the inner peripheral surface on the side of the plate wall 9a and the outer peripheral surface of the open portion of the noise damper cylinder 20 to prevent leakage of pressure oil. Further, on the outer peripheral surface on the open end side of the cylindrical wall portion 9b, two rotation stopping projections 94, 94 are integrally provided with a phase difference of 180 degrees. The noise damper tube 20 has a fitting portion 23 near the bottom 22 of the tube portion 21, and a male screw screwed to the female screw is provided on an outer peripheral surface of the fitting fixed portion 23, and the male screw portion is screwed to the female screw portion. Thus, it is detachably attached to the second housing supporting solid 9.

On the outer periphery of the bottom 22 of the noise damper cylinder 20,
A plurality of engaging recesses 24 are provided at regular intervals in the circumferential direction,
The tool is engaged with the engaging recesses 24..., And the noise damper cylinder 20 is rotated in a state where the tool is engaged with the rotation stopping projection 94 of the second housing partition plate 9. The noise damper cylinder 20 can be attached without rotating the noise damper 9. As shown in FIG. 1, the inner surface of the bottom 22 of the noise damper cylinder 20 has a curved surface shape that continuously curves inward from the outer peripheral portion to the radial center, disperses the points of action of the pressure oil, and can withstand high-pressure oil. Like that.

The first housing support 8 includes a substantially L-shaped third discharge oil passage 81 communicating with the second discharge oil passage 74, a relief oil passage 82 opening to the third discharge oil passage 81, An annular oil return path 83 that communicates with the relief oil path 82 via a relief valve 14 mounted on the relief oil path 82, and an insertion hole 84 through which the driven shaft 4 is inserted. An oil seal 15 is provided. Oil return path 83
Is a low-pressure chamber 1 defined in the tank housing 10.
6, the relief hydraulic fluid can be returned to the low-pressure chamber 16.

The relief valve 14 includes a valve element 14a for closing the relief passage 82 and a valve spring 14 for urging the valve element 14a.
b and a valve housing 14c for holding the valve element 14a and the valve spring 14b. The cartridge type is removably inserted and held in the relief passage 82, and when the third discharge oil passage 81 is over-pressurized, The valve element 14a is opened. Further, the valve housing 14c is in contact with the plate wall 9a of the second housing support 9 and is prevented from falling off.

The tank housing 10 has a clamp ring 17 abutting against its opening flange 10a and four fixing bolts 40 penetrating the clamp ring 17 in the axial direction.
And is detachably attached to one side surface of the first housing support 8 via the first housing support 8. The inside of the tank housing 10
Used as an oil tank for storing hydraulic oil. A circular partition plate 18 is inserted and fixed in the tank housing 10,
A low-pressure chamber 16 surrounding the pump housing 7, the second housing support 9 and the noise damper cylinder 20 is returned between the partition plate 18 and the bottom portion 10b between the partition plate 18 and the first housing support 8. Each of the chambers 19 is defined. Hydraulic oil stored in a sub-tank (not shown) is dropped and supplied to the return chamber 19 by its own weight.
The pressure is supplied to the low-pressure chamber 16 through a.

The oil return hole 18a is formed in the radially lower side of the partition plate 18, and the oil return hole 18a of the return chamber 19 is formed.
From the pressure chamber 16 and return to the low-pressure chamber 16. Further, the plate wall portion 9a of the second housing support 9 is provided with a valve hole 95 opened to the discharge chamber 72, and a check valve having a valve element and a valve spring for urging the valve element in the valve hole 95. 41
If the electric motor 2 is stopped due to a failure while the hydraulic oil is being supplied to one working chamber of the hydraulic operating device, one of the hydraulic oil in the high-pressure hydraulic passage to which the hydraulic oil is being supplied is provided. The portion can be returned from the discharge chamber 72 to the noise damper cylinder 20 via the check valve 41.

Driven shaft (pump shaft) supporting the drive gear 5
Is protruded toward the electric motor 2 through the insertion hole 84 of the first housing support 8 and is coaxial with the drive shaft 1 (motor shaft) of the electric motor 2 fixedly supported on the other side of the first housing support 8. The drive shaft 1 and the driven shaft 4 are connected by the drive shaft 3. The drive joint 3 attached as described above performs an operation of transmitting the rotation of the electric motor 2 as a drive source to the driven shaft 4 via the drive shaft 1 so that the electric pump performs a pump operation. In the electric pump, the driving gear 5 and the driven gear 6 rotate through the driving shaft 1 (sweater shaft) and the driven shaft 4 (pump shaft) by the driving of the electric motor 2, and the driving and driven gears 5 and 6 rotate. As a result, the operating oil in the low-pressure chamber 16 is supplied to the muffler pipe 80 and the second suction pipe 2
7 is sucked into the suction chamber 71, and each oil chamber defined by the space between each tooth portion and the peripheral surface of the gear chamber is discharged into the discharge chamber 72.
Oil is generated each time it is opened to the noise damper cylinder 2 through the first discharge oil passage 75 and the first communication passage 91.
It is supplied within 0.

Since the capacity chamber 20a of the noise damper cylinder 20 has a larger volume than the discharge chamber 72, the pulsation of the pressure oil is reduced. In particular, since the shock and pulsation of the oil pressure fluctuation are absorbed by the volume change due to the elasticity of the elastomer member 32, the oil pressure fluctuation can be absorbed with good followability. Also, unlike the conventional accumulator, there is no need to provide a gas chamber, and the size can be reduced. Further, there is no possibility that gas is mixed into the oil unlike the conventional accumulator.

In particular, since the elastomer member 32 is provided inside the noise damper cylinder 20, the structure is simple, and the elastomer member 32 is connected to the noise damper cylinder 20.
Because it has a bottomed cylindrical shape substantially along the inner wall, a sufficient pressure receiving area can be secured while using a conventional space. Therefore, a sufficient amount of volume change of the elastomer member 32 can be obtained even with a slight change in the hydraulic pressure, and from this point, the followability to the change in the hydraulic pressure can be greatly improved, and the change in the hydraulic pressure can be reliably absorbed. be able to.

Further, since the bottomed cylindrical elastomer member 32 is adhered to the inner wall of the noise damper tube 20 by lining, the elastomer member 32 does not hinder the air bleeding work at the time of assembly. Since the noise damper cylinder 20 is provided to reduce the pulsation of the pressure oil, the vibration of the driven shaft 4 due to the pulsation can be reduced. The pressure oil in the noise damper cylinder 20 is supplied to the second communication hole 92, the second and third communication holes 92, and
The oil is supplied to one working chamber of the hydraulic working device via the discharge oil passages 74 and 81. The hydraulic oil returned to the return chamber 19 from the oil return pipe 42 communicating with the other working chamber of the hydraulic operating device is decompressed through the oil return hole 18 a of the partition plate 18 and returned to the low-pressure chamber 16.

FIG. 5 shows another embodiment of the present invention. Referring to FIG. 5, the present embodiment is different from the embodiment of FIG. 1 in that elastomer member 32A of the present embodiment is a peripheral wall 30 which is an inner wall of noise damper cylinder 20.
And the outer surface of the elastomer member 32A and the noise damper cylinder 20 opposed thereto
A slight gap is provided between the inner wall surface and the inner wall surface. This gap is not sealed and is full of oil.
Further, a bellows portion 38 is provided on the inner surface of the elastomer member 32A as an undulating shape for increasing the surface area.

In the present embodiment, the same functions and effects as those of FIG. 1 are obtained. In addition, by further increasing the pressure receiving area by the bellows portion 38, the ability to follow the hydraulic pressure fluctuation is further improved, and the hydraulic pressure fluctuation can be more reliably absorbed. The undulating shape may be, for example, a wart shape or a pleated shape. In addition, a small hole that penetrates the elastomer member 32A inside and outside may be provided. The present invention is not limited to the above embodiments, and the present invention can be applied to other known hydraulic pumps such as a trochoid pump. In addition, various changes can be made within the scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a sectional view of a gear pump as a hydraulic pump according to an embodiment of the present invention.

FIG. 2 is a sectional view of the gear pump from another angle.

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

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is a sectional view of a main part of a gear pump as a hydraulic pump according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 5 drive gear 6 driven gear 7 pump housing 7a body 7b, 7c side plate 8 first housing support 9 second housing support 20 noise damper cylinder 20a capacity chamber 30 peripheral wall surface 31 bottom wall surface 32, 32A elastomer member 33 peripheral wall portion 34 Bottom wall 38 Bellows part (undulating shape) 70 Pump chamber 71 Suction chamber 72 Discharge chamber

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H044 AA02 BB02 BB03 CC11 CC13 CC16 CC19 CC21 DD10 DD13 DD23 DD24 DD28 3H075 AA02 BB06 CC03 CC17 CC30 CC34 CC36 DA11 DA17 DB03

Claims (3)

[Claims] 1. A hydraulic pump having a noise damper cylinder communicating with a discharge chamber of a pump housing having a suction chamber and a discharge chamber, wherein a bottomed cylindrical elastomer member substantially along an inner wall of the noise damper cylinder is housed. Features a hydraulic pump. 2. The hydraulic pump according to claim 1, wherein said elastomer member is fixedly attached to an inner wall surface of said noise damper cylinder. 3. The hydraulic pump according to claim 1, wherein an undulating shape for increasing a surface area is provided on an inner surface of the elastomer member.