JP3665696B2 - Hydraulic pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic pump such as a gear pump.
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, the gear pump is used in various industrial fields as a small and light pump having a simple structure, in addition to a power steering device and an automatic transmission in an automobile.
As a structure of this type of gear pump, a pair of side plates are fitted into a cavity inside a housing to define a pump chamber, and a pair of gears that mesh with each other are accommodated inside the pump chamber, and a support shaft of each gear is provided. The side holes are fitted and supported by support holes formed in each side plate, and a low pressure chamber for sucking hydraulic oil and a high pressure chamber for discharging hydraulic oil are formed inside the pump chamber with the meshing positions of both gears interposed therebetween. The type is common.
[0003]
On the other hand, in recent years, there has been a demand for a small-sized and high-rotation gear pump having high discharge pressure for the purpose of energy saving. However, due to the increase in speed, for example, radiated sound such as rattling noise increases from the pump chamber. In order to prevent the noise caused by this, conventionally, it has been difficult to make a soundproof or vibration-proof structure. This noise problem is not limited to gear pumps, but also exists in trochoid pumps and other hydraulic pumps.
[0004]
Then, the subject of this invention is providing the hydraulic pump which can reduce a radiation noise.
[0005]
[Means for Solving the Problems]
In order to solve the above-described problem, the hydraulic pump according to the first aspect of the present invention is a hydraulic pump that compresses hydraulic oil sucked into the suction chamber from the suction destination via the suction oil passage and discharges the hydraulic oil from the discharge chamber via the discharge oil passage. A suction pipe having an L-shape that forms a suction port that opens to the suction chamber, the suction oil passage including a portion formed by the suction pipe, and a bent portion of the suction pipe . The diameter is gradually reduced.
[0006]
In this configuration, since the diameter of the suction oil passage is narrowed, it is possible to suppress noise generated in the pump chamber from leaking outside through the suction oil passage.
Here, when the diameter of the suction oil passage is narrowed, the minimum diameter of the suction oil passage is set to a value within a range in which sufficient noise prevention can be achieved while smoothly supplying hydraulic oil to the suction chamber. It means that there is. Specifically, it is in the range of 20% to 75% of the suction port diameter that is normally set based on JIS. That is, when the diameter of the set suction oil passage is smaller than 20% of the normal suction port diameter, the suction chamber tends to be negative pressure, and the pump efficiency is lowered. On the other hand, if the diameter of the set suction oil passage is larger than 75% of the normal suction port diameter, the noise prevention effect is reduced. Preferably, it is more effective to set in the range of 30% to 60%.
[0007]
A hydraulic pump according to a second aspect of the present invention is the hydraulic pump according to the first aspect, further comprising a rubber silencer pipe connected to the suction pipe, wherein the suction oil passage includes a portion formed by the silencer pipe. It is a feature. In this configuration, the sound can be silenced by the silencer tube.
A hydraulic pump according to a third aspect of the present invention is the normally closed oil according to the first or second aspect , comprising a check valve that opens to the suction chamber and opens only when the suction chamber reaches a predetermined negative pressure. A road is further provided.
In this configuration, if some conditions overlap (for example, the viscosity of the hydraulic oil is high at low temperatures), the flow resistance of the suction oil passage increases and the flow rate of the hydraulic oil through the suction oil passage is insufficient. When the suction chamber reaches a predetermined negative pressure, hydraulic oil is supplied into the suction chamber through a normally closed oil passage that is opened by opening the check valve. Thus, since the suction flow rate is ensured when negative pressure is generated, the pump efficiency does not decrease.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof. 1 is a longitudinal side view of a hydraulic pump according to an 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. 4 is a sectional view taken along line IV-IV in FIG.
[0009]
The hydraulic pump A shown in FIGS. 1 to 4 is 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) linked to the drive shaft 1 via a drive joint 3. A drive gear 5 driven via the driven shaft 4, a driven gear 6 meshed with the drive gear 5, and a suction chamber 71 and a discharge chamber 72 formed by meshing of the drive and driven gears 5 and 6. A pump housing 7 (see FIG. 3), first and second housing supports 8, 9 for supporting the pump housing 7 from both sides, and a second housing support in a state combined with the first housing support 8. And a bottomed cylindrical tank housing 10 that covers the outside of the body 9 and the pump housing 7.
[0010]
1, 2 and 3, the pump housing 7 accommodates the drive gear 5 and the driven gear 6, and has a cylindrical body 7a having a pump chamber 70 as an oval gear chamber communicating with each other. , And a pair of side plates 7b, 7c for closing the opening portions on both sides of the pump chamber 70. The pump housing 7 has two sets of bearing holes 11 and 12 drilled in the side plates 7 b and 7 c, the drive gear 5 and the driven gear 5 via the driven shaft 4 and the driven shaft 51 parallel to the driven shaft 4. The driven gear 6 is alternately meshed and supported rotatably, and 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 is driven and driven. The pump 5 is configured to receive between the teeth of the gears 5 and 6 and seal it between the inner peripheral surface of the pump chamber 70 and send it to the discharge chamber 72.
[0011]
A suction port 73 that opens to the pump chamber 70 is provided at one place of the body portion 7a, a second discharge oil passage 74 that penetrates in the axial length direction is provided on the opposite side, and the discharge port is provided on one side plate 7b. A first discharge oil passage 75 having a discharge port that opens to the chamber 72 is provided. Between the first suction pipe 29 communicating with the tank housing 10 that is the suction port tip and the L-shaped second suction pipe 27 forming the suction port 73, rubber that extends upward along the inner peripheral surface of the low-pressure chamber described later. A sound deadening pipe 11 is connected so that the sound generated when the pressure oil sealed between the pair of meshing teeth of the driving and driven gears 5 and 6 is returned to the suction chamber 71 can be eliminated. I have to. A suction oil passage 35 is formed by the first suction pipe 29, the muffler pipe 11, and the second suction pipe 27.
[0012]
Here, the diameter d of the suction oil passage 35 (meaning the minimum diameter, which corresponds to the minimum diameter of the second suction pipe 27 in the present embodiment) is that noise generated in the pump chamber 70 is externally passed through the suction oil passage 35. It is squeezed so as to prevent leaking. The degree of restriction is set in a range in which the hydraulic oil can be smoothly supplied to the suction chamber 71 and sufficient noise prevention can be achieved.
[0013]
Specifically, it is in the range of 20% to 75% of the suction port diameter that is normally set based on JIS. That is, if the set diameter d of the suction oil passage 35 is smaller than 20% of the normal suction port diameter, the suction chamber 31 becomes negative pressure and the pump efficiency is likely to be lowered, while the set suction oil passage 35 is set. If the diameter d is greater than 75% of the normal suction port diameter, the noise prevention effect is reduced, so this range was set. Preferably, it is more effective to set in the range of 30% to 60%.
[0014]
On the other hand, the discharge oil passage 36 includes the first discharge oil passage 75, the first communication hole 91, the oil passage 26 of the discharge cylinder 25, the capacity chamber 20a, the second communication hole 92, and the pump that are formed in the side plate 7b. A second discharge oil passage 74 formed in the body 7 a of the housing 7 and an L-shaped third discharge oil passage 81 formed in the first housing support 8 and opening at the connection port 37 are included. In the discharge oil passage 36, the oil passage 26 of the discharge cylinder 25 has a minimum diameter, and the restriction by the oil passage 26 prevents noise generated in the pump chamber 70 from leaking outside through the discharge oil passage 36. ing. The connection port 37 is a connection port connected to an external discharge destination, for example, a power steering device.
[0015]
The first housing support 8 that supports the pump housing 7 is detachably attached to the motor housing of the electric motor 2, and the second housing support 9 is attached to the outer surface of the body portion 7a as shown in FIG. It is detachably attached to the first housing support 8 via four screw bodies 12 arranged along the same, and the pump housing 7 is clamped and fixed by attaching the second housing support 9. I have to.
[0016]
The second housing support 9 includes a first communication hole 91 that communicates with the first discharge oil passage 75 and a second communication hole 92 that is formed in parallel with the first communication hole 91. A plate wall portion 9a that is in contact with one end in the axial direction of the tube wall portion, and a cylindrical wall portion 9b that is connected to the outer peripheral portion of the plate wall portion 9a. A fitting portion 93 into which the portion 23 is screwed is provided, and the female screw of the fitting portion 93 communicates with the discharge chamber 72 via the oil passage 26 and the first discharge oil passage 75 of the discharge cylinder 24; A bottomed noise damper cylinder 20 having a capacity chamber 20a larger in volume than the discharge chamber 72 is detachably attached. A discharge cylinder 24 having an oil passage 26 connected to the first communication hole 91 of the plate wall 9 a is accommodated in the noise damper cylinder 20 so as to reach the bottom 22.
[0017]
The cylindrical wall portion 9b has a length that is inserted from the open end to the bottom of the noise damper cylinder 20, and is formed between the inner peripheral surface on the plate wall portion 9a side of the cylindrical wall portion 9b and the open outer peripheral surface of the noise damper cylinder 20. A seal body 13 is interposed therebetween to prevent leakage of pressure oil. Further, two rotation stop projections 94, 94 are integrally projected with a phase difference of 180 degrees on the outer peripheral surface on the open end side of the cylindrical wall portion 9b.
[0018]
The noise damper cylinder 20 has a fitting portion 23 near the bottom 22 of the cylinder portion 21. A male screw that is screwed into the female screw is provided on the outer peripheral surface of the fitting fixing portion 23, and the male screw portion is screwed to the female screw portion. Thus, the second housing support solid 9 is detachably attached.
On the outer periphery of the bottom 22 of the noise damper cylinder 20, a plurality of engaging recesses 24 are provided at equal intervals in the circumferential direction, a tool is engaged with the engaging recesses 24, and the second housing partition plate. The noise damper cylinder 20 can be attached without rotating the second housing support 9 together by rotating the noise damper cylinder 20 with the tool engaged with the rotation stop projection 94 of the body 9.
[0019]
As shown in FIG. 1, the inner surface of the bottom 22 of the noise damper cylinder 20 has a curved shape that curves inward continuously from the outer periphery to the center in the radial direction, disperses the working point of pressure oil, and can withstand high pressure oil. I am doing so.
The first housing support 8 includes a substantially L-shaped third discharge oil passage 81 that communicates with the second discharge oil passage 74, a relief oil passage 82 that opens to the third discharge oil passage 81, and the relief oil passage An annular oil return passage 83 communicating with the relief oil passage 82 via a relief valve 14 attached to the passage 82 and an insertion hole 84 through which the driven shaft 4 is inserted. The oil seal 15 is inserted into the insertion hole 84. Is provided. The oil return path 83 communicates with the low pressure chamber 16 defined in the tank housing 10 so that the hydraulic fluid that has been relieved can be returned to the low pressure chamber 16.
[0020]
The relief valve 14 is a cartridge type including a valve body 14a that closes the relief passage 82, a valve spring 14b that urges the valve body 14a, and a valve housing 14c that holds the valve body 14a and the valve spring 14b. The relief passage 82 is detachably inserted and held, and the valve body 14a is opened when the third discharge oil passage 81 is overpressured. Further, the valve housing 14c is in contact with the plate wall portion 9a of the second housing support 9 and is prevented from coming off.
[0021]
The tank housing 10 includes a clamp ring 17 abutted against the opening flange 10a, and four fixing bolts 40 passing through the clamp ring 17 in the axial length direction. Removably attached to the side.
The inside of the tank housing 10 is used as an oil tank that stores hydraulic oil. A circular partition plate 18 is inserted and fixed in the tank housing 10, and the pump housing 7, the second housing support 9 and the noise damper cylinder 20 are surrounded between the partition plate 18 and the first housing support 8. A return chamber 19 is defined between the partition plate 18 and the bottom portion 10b. The return chamber 19 is supplied with hydraulic oil stored in a sub-tank (not shown) by its own weight, and further supplied from the return chamber 19 through the three oil return holes 18a to the low pressure chamber 16 until it is full. Is done.
[0022]
The oil return hole 18a is formed on the lower side of the partition plate 18 in the radial direction so that the oil return hole 18a of the return chamber 19 is decompressed and returned 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 that opens to the discharge chamber 72, and the valve hole 95 includes a valve body and a valve spring that biases the valve body. 41, and when the electric motor 2 is stopped due to a failure in a state where the pressure oil is supplied to the one side working chamber of the hydraulically operated device, the hydraulic oil in the high pressure side hydraulic path to which the pressure oil is supplied A part can be returned from the discharge chamber 72 through the check valve 41 into the noise damper cylinder 20.
[0023]
The driven shaft (pump shaft) that supports the drive gear 5 passes through the insertion hole 84 of the first housing support 8 and protrudes toward the electric motor 2, and is electrically supported by being fixedly supported on the other side of the first housing support 8. The drive shaft 1 (motor shaft) of the motor 2 is abutted coaxially, and the drive shaft 1 and the driven shaft 4 are connected by the drive shaft 3.
[0024]
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, when the electric motor 2 is driven, the drive gear 5 and the driven gear 6 are rotated through the drive shaft 1 (setter shaft) and the driven shaft 4 (pump shaft), and the drive and driven gears 5 and 6 are rotated. Accordingly, the hydraulic oil in the low pressure chamber 16 is sucked into the suction chamber 71 from the muffler pipe 11 and the second suction pipe 27 of the suction oil passage 35, and is further defined by the space between the tooth portions and the gear chamber peripheral surface. Each time each oil chamber is opened to the discharge chamber 72, pressure oil is generated, and this pressure oil is supplied into the noise damper cylinder 20 through the first discharge oil passage 75 and the first communication passage 91. Since the capacity chamber 20a of the noise damper cylinder 20 has a larger volume than the discharge chamber 72, the pressure oil pulsation is reduced.
[0025]
Since the noise damper cylinder 20 is thus 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 one-side working chamber of the hydraulic operating device through the second communication hole 92, the second and third 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-side working chamber of the hydraulic operating device is decompressed from the oil return hole 18a of the partition plate 18 and returned to the low pressure chamber 16.
[0026]
And in this embodiment, since the diameter d of the suction oil path 35 which connects the low pressure chamber 16 used as a suction destination and the suction chamber 71 is narrowed rather than usual, the noise which generate | occur | produces in the pump chamber 70 is the suction oil path. Leakage to the outside through 35 can be suppressed. Moreover, since the diameter of the discharge oil passage 36 is also narrowed by the discharge cylinder 24, noise leaking to the outside from the pump chamber 70 via the discharge oil passage 36 can be suppressed.
[0027]
Next, FIG. 5 schematically shows another embodiment of the present invention. Referring to the figure, this embodiment is different from the embodiment of FIGS. 1 to 4 in that a normally closed oil passage 47 is provided which communicates the suction chamber 71 and the suction pipe 29 and is normally closed. That is. The normally closed oil passage 47 is provided with a check valve 42 that opens only when the inside of the suction chamber 71 reaches a predetermined negative pressure. The check valve 42 includes, for example, a ball valve that elastically urges a ball 43 as a valve body toward the valve seat 45 by an urging member 44 such as a compression coil spring. Further, the suction oil passage 35 and the normally closed oil passage 47 are each formed in a dogleg shape that is bent in the opposite direction. Reference numerals 33 and 34 denote a suction port and a discharge port, respectively.
[0028]
In the present embodiment, the following effects can be achieved. That is, for example, because the viscosity of the hydraulic oil is high at low temperatures, the flow resistance of the suction oil passage 35 increases, the flow rate of the hydraulic oil through the suction oil passage 35 becomes insufficient, and the suction chamber 71 becomes negative pressure. May end up. In such a case, the check valve 42 is opened in response to the suction chamber 71 having a predetermined negative pressure, and hydraulic oil is supplied into the suction chamber 71 through the normally closed oil passage 47 opened thereby. The As a result, since the suction flow rate is ensured when negative pressure is generated, the pump efficiency can be prevented from being lowered, and therefore noise can be suppressed without lowering the pump efficiency.
[0029]
In addition, this invention is not limited to said each embodiment, This invention is applicable to other well-known hydraulic pumps, such as a trochoid pump. In addition, various modifications can be made within the scope of the present invention.
[0030]
【The invention's effect】
In the first aspect of the present invention, since the diameter of the suction oil passage is reduced more than usual, it is possible to suppress noise generated in the pump chamber from leaking outside through the suction oil passage.
In the invention described in claim 2, the sound can be silenced by the silencer tube.
In the third aspect of the invention, when the amount of working oil through the suction oil passage is insufficient, the working oil is supplied into the suction chamber through the normally closed oil passage that is opened. As a result, the pump efficiency does not decrease.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a gear pump as a hydraulic pump according to an embodiment of the present invention.
FIG. 2 is a sectional view from another angle of the gear pump.
3 is a cross-sectional view taken along line III-III in FIG.
4 is a cross-sectional view taken along line IV-IV in FIG.
FIG. 5 is a cross-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]
5 drive gear 6 driven gear 7 pump housing 7a body 7b, 7c side plate 8 first housing support 9 second housing support 11 muffler pipe 27 second suction pipe 29 first suction pipe 35 suction oil path 36 discharge oil path 42 Check valve 47 Normally closed oil passage 70 Pump chamber 71 Suction chamber 72 Discharge chamber

Claims (3)

In the hydraulic pump that compresses the hydraulic oil sucked into the suction chamber from the suction destination via the suction oil passage and discharges it from the discharge chamber via the discharge oil passage.
An L-shaped suction pipe that forms a suction port that opens into the suction chamber;
The suction oil passage includes a portion formed by the suction pipe,
The hydraulic pump , wherein a diameter of the suction oil passage is gradually narrowed at a bent portion of the suction pipe . A rubber silencer connected to the suction pipe,
The hydraulic pump according to claim 1, wherein the suction oil passage includes a portion formed by the silencer pipe . The normally closed oil path which has a check valve which connects the said suction chamber and a suction destination, and opens only when the said suction chamber becomes a predetermined negative pressure is provided. Hydraulic pump.

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