JP2005036687A - Hydraulic pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic pump capable of preventing leak oil from leaking to the outside due to the breakage of a seal member even when the amount of the leak oil is increased while securing lubricity between bushes and a drive shaft. <P>SOLUTION: This hydraulic pump comprises a pump housing 3 in which a through-hole 3a is formed, a pump unit 1 installed between the pump housing 3 and a pump cover 2, the drive shaft 15 pivotally supported in the through-hole 3a through the bushes 13 and 14, a seal chamber 11 formed at the end of the through-hole 3a, and the seal member 12. Also, the hydraulic pump comprises a first oil groove Y1 formed between the drive shaft 15 and the bushes 13 and 14 and allowed to communicate with the seal chamber 11 from the pump unit side of the through-hole 3a, a second oil groove Y2 allowed to communicate with the seal chamber 11 from the pump unit side of the through-hole 2a so as to avoid the first oil groove Y1, and a communication passage 19 communicating from the seal chamber 11 to the low-pressure side (low-pressure chamber 3c) of the pump unit 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic pump suitable for use in a power source such as a power steering device of an automobile.
[0002]
[Prior art]
Conventionally, this type of hydraulic pump is configured by housing a pump unit between a pump housing and a pump cover, and a through-hole penetrating the pump housing is provided with a drive shaft that is supported via a bush. ing.
Further, the hydraulic pump normally uses leaked oil that leaks into the through hole as the pump unit is driven as lubricating oil for the drive shaft.
Therefore, a hydraulic pump is formed in which a spiral oil groove is formed on the inner surface of the bush, and the leakage oil is circulated through the oil groove and led to the seal chamber to improve the lubricity between the bush and the drive shaft. This technique is known (see Patent Document 1).
Further, a technique in which an oil groove is formed between the bush and the through hole to achieve the same effect is known (see Patent Document 2).
[0003]
[Patent Document 1]
Japanese Utility Model Publication No. 63-143786 (page 1-3, FIG. 1)
[Patent Document 2]
JP 11-13670 A (page 1-3, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, in the invention of Patent Document 1 described above, when the leakage oil increases, the flow rate of the leakage oil flowing through the oil groove increases, and the stress exceeds the sealing force of the sealing member. There is a problem that the seal member is broken and leak oil may leak out of the pump housing from the space between the drive shaft.
In addition, if the flow rate of the leak oil flowing through the oil groove is increased, the load applied to the bush is also increased, so that the durability of the bush is also decreased.
Further, the opening end of the oil groove on the seal chamber side faces the lip portion of the seal member and is structured to be easily subjected to stress due to the flow rate of the leak oil.
Further, the invention of Patent Document 2 has a problem in that a desired lubricity cannot be obtained in the drive shaft because leak oil does not sufficiently penetrate between the bush and the drive shaft.
[0005]
The present invention has been made paying attention to the above-mentioned problems, and the purpose thereof is to ensure lubricity between the bush and the drive shaft, and even when leak oil increases, the seal member is damaged. An object of the present invention is to provide a hydraulic pump that can prevent leakage to the outside.
[0006]
[Means for Solving the Problems]
According to the first aspect of the present invention, a pump housing having a through hole formed therein, a pump unit housed between the pump housing and the pump cover, and a drive shaft pivotally supported by the through hole through a bush. A seal chamber and a seal member that are provided at an end portion of the through hole, seals between the pump housing and the drive shaft, and are provided between the drive shaft and the bush. A first oil groove that communicates from the pump unit side to the seal chamber and leaks leaked oil into the through hole from the pump unit to the seal chamber, and communicates from the pump unit side of the bush to the seal chamber and penetrates from the pump unit. A second oil groove that guides leaked oil leaking into the hole to the seal chamber so as to avoid the first oil groove, and communicated from the seal chamber to the low pressure side of the pump unit. A communication passage for recovering oil, was appreciated by one skilled in the art.
[0007]
Accordingly, the leaked oil leaked into the through hole from the pump unit side in the hydraulic pump according to the present invention flows into the first oil groove, thereby acting as a lubricating oil between the drive shaft and the bush. Lubricity is obtained.
[0008]
In addition, since the leak oil branches into two flow paths of the first oil groove and the second oil groove and is guided to the seal chamber, the second oil groove bypasses the first oil groove even when the leak oil increases. Thus, the entire amount of leak oil does not flow into the first oil groove.
[0009]
Therefore, compared with the conventional invention, the amount of leaked oil flowing into the first oil groove can be reduced and the flow velocity thereof can be lowered, and the bush and the seal member can be prevented from being damaged by the stress of the leaked oil.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the hydraulic pump of the present invention will be described.
In the present embodiment, an example in which the present invention is applied to a hydraulic pump of a power steering device, specifically, a vane pump will be described.
The hydraulic pump of the present invention is not limited to the application of the power steering device, and the pump type can be applied to all general liquid pumps such as a plunger pump and a piston pump.
[0011]
<Embodiment 1>
Embodiment 1 of the present invention will be described below.
1 is a sectional view showing a hydraulic pump according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line S1-S1 of FIG. 1, FIG. 3 is a development view of a bush according to the present embodiment, and FIG. It is the schematic explaining the flow path of the leak oil in this hydraulic pump.
[0012]
As shown in FIGS. 1 and 2, the hydraulic pump according to the present embodiment is provided with a pump cover 2 for housing the pump unit 1, a pump housing 3 in which a through hole 3a is formed, and the through hole 3a. The driven drive shaft 15 is the main component.
[0013]
The cam ring 4 of the pump unit 1 is provided in a state of being sandwiched between side plates 7 and 8 (to be described later), and a rotor 6 having a plurality of vanes 5 mounted in the cam ring 4 so as to be freely projecting and retracting in the radial direction is accommodated. Has been.
A pump chamber 9 is formed in the cam ring 4 and is separated by adjacent vanes 5.
The volume of the pump chamber 9 is changed by the rotation of the rotor 6, and a suction region is formed in a portion that is increased by the volume change, and a discharge region is formed in a portion in which the volume is reduced.
[0014]
The side plates 7 and 8 facing the discharge region are formed with notched passages 7a and 8a that are opened in the radial direction so that the internal hydraulic oil is discharged into the discharge chamber 20 in the annular recess on the outer periphery of the cam ring 4. It has become.
Further, a suction port (not shown) is formed through the side plate 7 facing the suction area.
[0015]
A seal chamber 11 and a seal member 12 are provided at the end of the through hole 3a of the pump housing 3, and a bush 13 (first bush) and a bush 14 (second bush), which will be described later, are provided in the through hole 3a. The drive shaft 15 is pivotally supported.
The drive shaft 15 is for driving the pump unit 1, and the serration 16 on the pump unit 1 side passes through the through hole 7 b of the side plate 7 and is fitted into the serration hole 6 a of the rotor 6, thereby The drive shaft 15 rotates the rotor 6, in other words, drives the pump unit 1.
The tip of the drive shaft 15 on the pump unit 1 side is loosely fitted in the through hole 8 a of the side plate 8.
[0016]
As shown in FIG. 3, each of the bushes 13 and 14 is formed in a cylindrical shape by rolling a plate member in which two grooves M are formed so that the grooves M are on the inner surface side.
The bushes 13 and 14 are provided at a predetermined interval in the axial direction of the drive shaft 15.
The predetermined interval is a distance necessary for bearing the drive shaft 15, for example, a dimension of about ３ or less between both ends of the bushes 13 and 14.
[0017]
The opening end of the first oil groove Y1 formed on the inner surface of the bush 13 on the seal chamber 11 side communicates with the seal member 12, specifically the lip portion R of the seal member 12.
On the other hand, the opening end of the first oil groove Y1 on the pump unit 1 side communicates with a space O1 sandwiched between the bushes 13 and 14.
[0018]
A second oil groove Y2 communicating with the seal chamber 11 from the space O1 is formed so as to avoid the first oil groove Y1.
The second oil groove Y2 is formed in the lowermost portion of the through hole 3a along the axial direction, and is separated from the first oil groove Y1 by a bush 14 (see FIG. 2).
Further, the opening end of the second oil groove Y2 on the seal chamber 11 side is in a state offset to the lip portion R radially outward, so that leakage oil, which will be described later, does not collide with the lip portion R vigorously. Has been.
On the other hand, the bush 14 also has a first oil groove Y3 formed in the same manner as the bush 13, and the first oil groove Y3 communicates with the space O2 on the pump unit 1 side and the space O1.
[0019]
Further, the pump housing 3 includes a low pressure chamber 3c (low pressure side of the pump unit) that communicates the pump chamber 9 in the suction region and an oil storage tank (not shown), a pump chamber 9 in the discharge region, and a power steering device (not shown). A discharge passage 3d for communicating with the actuator, a flow rate control valve S for controlling the flow rate by discharging surplus oil of the working oil in the discharge chamber 20 from a drain port (not shown) are provided.
[0020]
The low-pressure chamber 3c is formed to branch in two directions in the direction perpendicular to the axis at the joint with the side plate 7, and an arcuate suction port (not shown) is formed at the tip.
The low pressure chamber 3c is formed facing a suction port (not shown) formed in the side plate 7.
Further, the low-pressure chamber 3c communicates with the seal chamber 11 through a communication passage 19 formed substantially parallel to the through hole 3a.
[0021]
The pump housing 3 and the pump cover 2 are connected and fixed to each other by bolts or the like (not shown), and the joint between these two leaks the leaked oil discharged into the discharge chamber 20 by the seal portion 17 to the outside. It is supposed not to.
Further, a seal portion 18 is provided between the pump cover 2 and the side plate 8, and the space between the discharge chamber 20 and the through hole 3a is sealed.
A driving means P such as a pulley that is driven to rotate by an internal combustion engine (not shown) is attached to the tip of the drive shaft 15 protruding from the pump housing 3.
[0022]
Hereinafter, the operation of the hydraulic pump according to the present embodiment will be described.
In the hydraulic pump configured as described above, when the drive shaft 15 is rotated by the driving means P, the rotor 6 is rotationally driven.
Then, the hydraulic oil is supplied from the passage 3e to the low pressure chamber 3c by the rotational drive of the rotor 6, and then sucked into the pump chamber 9 in the suction region.
Here, the hydraulic oil is discharged from the pump chamber 9 in the discharge region into the discharge chamber 20 after receiving the pump action.
[0023]
Thereafter, the hydraulic oil discharged into the discharge chamber 20 is discharged to the actuator of the power steering apparatus (not shown) through the passage 3f of the discharge passage 3d while being controlled in flow rate by the flow control valve S.
The hydraulic oil is discharged from the passage 3f, while a space portion is formed along the drive shaft 15 from the pump unit 1 through a gap formed mainly for lubrication between the rotor 6 and the side plates 7 and 8. Leak into O2.
[0024]
The leaked oil leaked into the space portion O2 acts as lubricating oil in the space portion O2, and flows into the first oil groove Y3 of the bush 14 to act as lubricating oil between the drive shaft 15 and the space portion. Guided to O1.
[0025]
Next, the leaked oil flowing into the first oil groove Y1 of the bush 13 from the space O1 is guided to the seal chamber 11 while acting as a lubricating oil with the drive shaft 15.
On the other hand, the leaked oil flowing into the second oil groove Y2 from the space O1 is guided directly to the seal chamber 11 while avoiding the first oil groove.
[0026]
As described above, since the second oil groove Y2 is provided at the lowermost part of the through hole 3a, the leaked oil easily flows into the second oil groove Y2 by its own weight.
Moreover, since the leak oil in the second oil groove Y2 is not affected by the rotation of the drive shaft 15, the leak oil flows more smoothly than the first oil groove Y1.
Subsequently, the leaked oil flowing into the seal chamber 11 is returned to the low-pressure chamber 3 c on the low-pressure side of the pump unit 1 through the communication path 19 and circulates in the pump unit 1 again.
[0027]
That is, in the hydraulic pump of the present embodiment, as shown in FIG. 4, after the leaked oil leaked from the pump unit 1 side to the space O 2 gathers in the space O 1 through the first oil groove Y 3 of the bush 14. , A flow path (illustrated by solid line arrows) guided to the seal chamber 11 via the first oil groove Y1 of the bush 13 and a flow path (illustrated by broken line arrows) guided to the seal chamber 11 via the second oil groove Y2. Branches to (shown).
In FIG. 4, the second oil groove Y <b> 2 is illustrated at a side position of the drive shaft 15 for the sake of explanation.
[0028]
Therefore, in the hydraulic pump of the present embodiment, desired lubricity can be obtained between the drive shaft 15 and the bushes 13 and 14 by the first oil grooves Y1 and Y3 (corresponding to claim 1).
[0029]
Further, since the second oil groove Y2 serves as a bypass for the first oil groove Y1, the entire amount of the leak oil does not flow into the first oil groove Y1, and as a result, even when the leak oil increases, the first oil groove Y1 does not flow. The flow rate of the leaked oil in the oil groove Y1 can be reduced as compared with the conventional invention to reduce the flow rate of the leaked oil, and the bush 13 and the seal member 12 can be prevented from being damaged by the stress of the leaked oil. 1).
[0030]
Further, since the opening end of the second oil groove Y2 on the seal chamber 11 side is communicated with the lip portion R of the seal member 12 at a position offset in the radial direction, the leaked oil guided to the second oil groove Y2 is lip It is possible to avoid a direct collision with the portion R, and it is possible to improve the durability of the seal member 12 by avoiding excessive stress on the lip portion R (corresponding to (B) described later).
Further, in the present embodiment, the first oil groove Y1 is formed on the inner peripheral surface of the bush 13, so that it is not necessary to form an oil groove in the drive shaft 15 that requires strength, and the second oil groove Y2 is a through hole. The second oil groove Y2 can be formed at the same time as the through hole 3a by being formed on the inner peripheral surface of the space 3a (space O1) (corresponding to (d) described later).
[0031]
<Embodiment 2>
The second embodiment of the present invention will be described below.
In the hydraulic pump according to the present embodiment, the third embodiment except that the third oil groove Y4 communicating from the space O2 to the space O1 is formed so as to avoid the first oil groove Y3 of the bush 14. 1 are the same as those shown in FIG.
FIG. 5 is a schematic diagram for explaining the flow path of the leak oil in the second embodiment of the present invention.
[0032]
As shown in FIG. 5, the hydraulic pump of the present embodiment is formed with a third oil groove Y4 that communicates from the space portion O2 to the space portion O1 so as to avoid the first oil groove Y3 of the bush 14.
In FIG. 5, for the sake of explanation, the second oil groove Y2 and the third oil groove Y4 are shown at the side positions of the drive shaft 15, but the second oil groove Y2 is at the lowest position of the through hole 3a. The third oil groove Y4 is formed at the uppermost position of the through hole 3a.
[0033]
Hereinafter, the operation of the hydraulic pump according to the present embodiment will be described.
In addition, since the description about the action | operation of the pump unit 1 is the same as that of the said Embodiment 1, it abbreviate | omits.
[0034]
In the hydraulic pump according to the present embodiment, as in the first embodiment, leaked oil leaked from the pump unit 1 flows into the space O2 and acts as lubricating oil in the space O2.
[0035]
Next, the leaked oil that has flowed into the first oil groove Y3 of the bush 14 from the space O2 is guided to the space O1 while acting as a lubricating oil with the drive shaft 15.
On the other hand, leak oil that has flowed into the third oil groove Y4 from the space O2 flows directly into the space O1 while avoiding the first oil groove Y3.
Note that the leaked oil in the third oil groove Y4 is not affected by the rotation of the drive shaft 15, and therefore flows more smoothly than the first oil groove Y3.
[0036]
Next, the leaked oil that has flowed into the first oil groove Y <b> 1 of the bush 13 from the space O <b> 1 is guided to the seal chamber 11 while acting as lubricating oil for the drive shaft 15.
On the other hand, the leaked oil that flows into the second oil groove Y2 from the space O1 flows directly into the seal chamber 11 while avoiding the first oil groove Y1.
[0037]
Subsequently, the leaked oil that has flowed into the seal chamber 11 is returned to the low-pressure chamber 3 c through the communication passage 19 and circulates again in the pump unit 1.
That is, in the hydraulic pump of the present embodiment, the leaked oil leaking from the pump unit 1 collects in the space O2, and then flows into the space O1 via the first oil groove Y3 of the bush 13 (solid arrow) And a flow path (illustrated by a broken arrow) led to the space O1 through the third oil groove Y4.
[0038]
Therefore, in the hydraulic pump of the present embodiment, desired lubricity can be obtained between the bushes 13 and 14 and the drive shaft 15 by the first oil grooves Y1 and Y3 (corresponding to claim 1).
[0039]
Further, even when leak oil increases, the entire amount of leak oil that has flowed into the space O2 does not flow into the first oil groove Y3 of the bush 14, and as a result, the flow speed of the leak oil is lowered at an earlier stage. The breakage of the bushes 13 and 14 and the seal member 12 can be more effectively prevented (corresponding to (B) described later).
[0040]
The second oil groove Y2 is formed at the lowest position of the through hole 3a, and the third oil groove Y4 is formed at the lowest position of the through hole 3a. In other words, the second oil groove Y2 and the third oil groove Y4 are driven. Since it is formed at a position rotated 180 degrees with respect to the circumferential position of the shaft 15, the flow resistance of the leaked oil flowing into the second oil groove Y2 via the third oil groove Y4 can be increased, and as a result, the leak The oil flow rate can be effectively reduced.
[0041]
<Embodiment 3>
The third embodiment of the present invention will be described below.
The hydraulic pump of the present embodiment is the same as that of the first embodiment except that the second oil groove Y2 is omitted and the second communication passage 19a that communicates from the space O2 to the low pressure chamber 3c is formed. For this reason, the same constituent members are denoted by the same reference numerals, and the description thereof is omitted.
FIG. 6 is a schematic diagram for explaining the flow path of the leak oil in the third embodiment of the present invention.
[0042]
As shown in FIG. 6, the hydraulic pump of the present embodiment is formed with a second communication passage 19a that communicates from the space O2 to the low pressure chamber 3c.
The second communication passage 19a is provided at the uppermost part of the through hole 3a.
The second communication passage 19a is preferably provided with a flow rate control valve capable of adjusting the flow rate of leak oil, which will be described later.
[0043]
Hereinafter, the operation of the hydraulic pump according to the present embodiment will be described.
In addition, since the description about the action | operation of the pump unit 1 is the same as that of the said Embodiment 1, it abbreviate | omits.
[0044]
In the hydraulic pump of the present embodiment, the leaked oil leaked from the pump unit 1 collects in the space O2, as in the first embodiment.
Next, the leak oil acts as lubricating oil in the space O2, and flows into the first oil groove Y3 of the bush 14 and collects in the space O1 while acting as lubricating oil for the drive shaft 15.
[0045]
Next, the leaked oil that has flowed into the first oil groove Y1 from the space O1 is guided to the seal chamber 11 while acting as lubricating oil for the drive shaft 15, and is then guided to the low pressure chamber 3c via the communication passage 16. .
On the other hand, the leaked oil that has flowed from the space O1 into the second communication passage 19a is directly guided to the low pressure chamber 3c.
The leaked oil that has flowed into the low pressure chamber 3c from the second communication passage 19a and the first oil groove Y1 circulates in the pump unit 1 again.
[0046]
That is, in the hydraulic pump of the present embodiment, the leaked oil leaked from the pump unit 1 gathers in the space O2, and is guided to the space O1 via the first oil groove Y3 of the bush 14, and then the first oil It is branched into a flow path (illustrated by a solid line arrow) guided to the seal chamber 11 via the groove Y1 and a flow path (illustrated by a broken line arrow) guided to the low pressure chamber 3c via the second communication path 19a.
[0047]
Therefore, in the hydraulic pump of the present embodiment, desired lubricity can be obtained between the bushes 13 and 14 and the drive shaft 15 by the first oil grooves Y1 and Y3 (corresponding to claim 1).
[0048]
Further, since the flow rate of the leaked oil flowing through the first oil groove Y1 is reduced by the second communication passage 19a, even when the leaked oil increases, the flow rate of the leaked oil increases and the stress causes the lip R to break. Can be prevented (corresponding to (C) described later).
[0049]
Although the embodiment of the present invention has been described above, the specific configuration of the present invention is not limited to the present embodiment, and the present invention can be applied even if there is a design change or the like without departing from the gist of the invention. include.
For example, the shape, position, and number of formation of each oil groove through which leak oil flows can be set as appropriate.
A valve may be provided in the middle of each oil groove through which leaked oil flows.
[0050]
Furthermore, technical ideas other than the claims that can be understood from the above-described embodiments and examples will be described together with the effects thereof.
[0051]
(A) In the hydraulic pump according to claim 1,
A hydraulic pump characterized in that the opening end portion of the second oil groove on the seal chamber side is formed at a position offset in a radial direction from the lip portion of the seal member.
[0052]
That is, it is possible to avoid the leaked oil led to the second oil groove from strikingly directly colliding with the lip portion, and it is possible to reduce the extra stress applied to the lip portion and improve the durability of the seal member.
[0053]
(B) In the hydraulic pump according to claim 1 or (a),
The bush is composed of a first bush on the seal chamber side and a second bush on the pump unit side spaced apart at a predetermined interval in the axial direction,
A third oil groove that communicates between the bushes from the pump unit side of the second bush and guides leaked oil leaked into the through hole from the pump unit between the bushes so as to avoid the oil groove of the second bush. A hydraulic pump comprising:
[0054]
That is, even in a hydraulic pump of a type in which two bushes are provided in the axial direction of the drive shaft, the entire amount of leaked oil that has flowed into the pump unit side of the second bush flows into the first oil groove of the second bush. Furthermore, when the leak oil increases, the flow rate of the leak oil flowing into the seal chamber at an earlier stage can be lowered, and damage to the first and second bushes and the seal member can be prevented more effectively.
[0055]
(C) a pump housing having a through hole;
A pump unit housed between the pump housing and the pump cover;
A drive shaft pivotally supported in the through hole via a bush;
A seal chamber and a seal member which are provided at an end of the through hole and seal between the pump housing and the drive shaft;
A first oil groove that is provided between the drive shaft and the bush, and that communicates with the seal chamber from the pump unit side of the through hole and leaks leaked oil into the through hole from the pump unit to the seal chamber;
A communication path communicating from the seal chamber to the low pressure side of the pump unit, and collecting leaked oil in the seal chamber;
A second communication path communicating from the pump unit side of the bush to the low pressure side of the pump unit and guiding leaked oil leaking from the pump unit into a through hole to the low pressure side of the pump unit so as to avoid the first oil groove; ,
A hydraulic pump comprising:
[0056]
That is, the leaked oil that has flowed into the pump unit side of the bush is branched into two channels: a flow path that leads to the seal chamber via the first oil groove and a flow path that directly flows into the low pressure side of the pump unit. The total amount of oil does not flow into the first oil groove of the bush, and as a result, the leaked oil flowing into the first oil groove can be reduced, and damage to the bush and the seal member can be prevented more effectively.
[0057]
(D) In the hydraulic pump according to claim 1, (a) to (c) above,
The first oil groove is formed on an inner peripheral surface of the bush;
The hydraulic pump according to claim 1, wherein the second oil groove is formed between the through hole and the bush and on an inner peripheral surface of the through hole.
[0058]
That is, since the first oil groove is formed on the bush side, it is not necessary to form the oil groove on the drive shaft that requires strength, and the second oil groove is formed on the inner peripheral surface of the through hole. The second oil groove can be formed simultaneously with the through hole.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a hydraulic pump according to a first embodiment of the present invention.
2 is a cross-sectional view taken along line S1-S1 of FIG.
FIG. 3 is a schematic diagram illustrating a flow path of leak oil according to the present embodiment.
FIG. 4 is a development view of the bush according to the present embodiment.
FIG. 5 is a schematic diagram illustrating a flow path of leak oil according to the present embodiment.
FIG. 6 is a schematic diagram illustrating a flow path of leak oil according to the present embodiment.
[Explanation of symbols]
O1, O2 Space P Driving means R Lip part S Flow rate control valve Y1, Y3 First oil groove Y2 Second oil groove Y4 Third oil groove 1 Pump unit 2 Pump cover 3 Pump housing 3a Through hole 3c Low pressure chamber 3d Discharge passage 3e, 3f passage 4 cam ring 5 vane 6 rotor 6a serration hole 7, 8 side plate 7a, 8a notch passage 9 pump chamber 11 seal chamber 12 seal member 13, 14 bush 15 drive shaft 16 serrations 17, 18 seal portion 19 communication passage 19a Second communication passage 20 Discharge chamber

Claims (1)

A pump housing having a through hole formed therein;
A pump unit housed between the pump housing and the pump cover;
A drive shaft pivotally supported in the through hole via a bush;
A seal chamber and a seal member which are provided at an end of the through hole and seal between the pump housing and the drive shaft;
A first oil groove that is provided between the drive shaft and the bush, and that communicates with the seal chamber from the pump unit side of the through hole and leaks leaked oil into the through hole from the pump unit to the seal chamber;
A second oil groove that communicates with the seal chamber from the pump unit side of the bush and guides leaked oil leaked into the through hole from the pump unit to the seal chamber so as to avoid the first oil groove;
A communication path communicating from the seal chamber to the low pressure side of the pump unit, and collecting leaked oil in the seal chamber;
A hydraulic pump comprising:

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