JP2006132330A - Pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pump device materializing a mechanism adjusting pressing force of a sealing body against a gear side part according to pressure of working fluid with a simple structure. <P>SOLUTION: A gear pump device 10 is provided with a gear 30 sending hydraulic oil to a high pressure side flow pass 40 from a low pressure side flow pass 42, and a case 14 pressed against the side part 36 of the gear 30. hydraulic oil in the high pressure side flow pass 40 is led to a first pressure operating surface 16 and a second pressure operating surface 18 formed on the case 14 in a multi-stage shape. The valves 20, 22 leads hydraulic oil in the high pressure side flow pass 40 to the second pressure operating surface 18 when pressure of hydraulic oil in the high pressure side flow pass 40 and leads hydraulic oil in the low pressure side flow pass 42 to the second pressure operating surface 18 when pressure of hydraulic oil in the high pressure side flow pass 40 is low. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pump device having a gear, and more particularly to a pump device applicable to a gear pump that can be used as a hydraulic source such as a hydraulic suspension for vehicles.

A gear pump is sometimes used as a hydraulic source of a hydraulic system because of its simple structure, small size, light weight, and excellent noise characteristics, and several techniques for improving the gear pump have been proposed. For example, Patent Document 1 proposes a variable displacement gear pump that changes the oil liquid discharge capacity with a simple structure.
JP 2002-106479 A

  When a working fluid such as oil leaks from the side of a gear used in a pump device such as a gear pump, the operating efficiency related to the discharge of the working fluid accompanying the rotation of the gear may be reduced. Therefore, the discharge efficiency of the working fluid can be kept good by pressing the seal body against the side of the gear to improve the sealing performance of the side of the gear in order to fill the gap on the side of the gear. Note that the pressing of the seal body against the gear side portion is particularly called “pressure loading”. In this pressure loading, from the viewpoint of improving the sealing performance of the gear side portion, it is preferable to strongly press the seal body against the gear side portion. However, if the sealing body is strongly pressed against the gear side portion, the seal body and the gear side portion are preferably pressed. The frictional force generated between the two increases, which may hinder the improvement of the discharge efficiency of the working fluid. Therefore, depending on the discharge pressure of the working fluid adjusted by the pump device, there is a “pushing force of the seal body against the gear side” indicating the optimum discharge efficiency of the working fluid. The upper limit of the discharge pressure of the working fluid is also limited according to the “force”. Therefore, it is preferable to adjust the “pressing force of the seal body against the gear side portion” according to the desired discharge pressure of the working fluid, and in particular, the adjustment of the “pressing force of the seal body against the gear side portion” is simplified. It is preferable to achieve with a simple configuration.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pump device that achieves a mechanism that adjusts the pressing force of the seal body against the gear side portion according to the pressure of the working fluid with a simple configuration. It is to propose.

  One aspect of the present invention relates to a pump apparatus including a gear disposed in a housing. The pump device includes a pressure acting portion including at least one pressure acting surface, and changes a pressing force against the side portion of the gear according to pressure applied to the pressure acting surface, thereby operating the side portion of the gear. A seal body that changes the degree of sealing of the flow of fluid according to the pressing force; and a pressure adjusting means that controls the area of the pressure acting surface to which a high pressure is applied according to the pressure of the working fluid in the housing; It is characterized by providing.

  According to the pump device, since the area of the pressure acting surface to which high pressure is applied is adjusted according to the pressure of the working fluid in the housing, the pressing force against the side of the gear according to the pressure of the working fluid in the housing And the degree of sealing of the working fluid flow at the side of the gear is controlled. Thus, in the pump device, the pressure adjusting means appropriately changes the characteristic of the pressure acting portion of the seal body in accordance with the pressure of the working fluid in the housing, thereby allowing the working fluid to flow in the side portion of the gear. Adjust the degree of stopping.

  The pressure acting part may have a plurality of pressure acting surfaces, and the pressure adjusting means may control the number of pressure acting surfaces to which a high pressure is applied according to the pressure of the working fluid in the housing. In this case, the area of the pressure acting surface to which the high pressure is applied is adjusted by adjusting the number of pressure acting surfaces to which the high pressure is applied according to the pressure of the working fluid in the housing.

  The pressure adjusting means may apply a high pressure to the pressure acting surface using a working fluid in the housing. In this case, the working fluid in the housing can be effectively utilized.

  The seal body may include at least one step portion constituting the pressure acting portion, and the pressure acting surface may be constituted by the step portion. In this case, the pressure acting portion and the pressure acting surface can be configured with a simple structure called a stepped portion.

  The working fluid in the housing is divided into a low-pressure working fluid and a high-pressure working fluid through the gear, and the pressure adjusting means is on the high-pressure working fluid side of the side portion of the gear with respect to the low-pressure working fluid side portion. The area of the pressure acting surface to which a high pressure is applied may be controlled so that the side of the pressure member is strongly pressed by the seal body.

  Usually, the stronger the seal body is pressed against the gear side, the higher the effect of sealing the flow of working fluid in the gear side. Therefore, according to the pump device, since a high sealing effect can be ensured at least on the side portion on the high pressure working fluid side, it is possible to effectively prevent the high pressure working fluid from flowing into the low pressure working fluid. .

  According to the present invention, the area of the pressure acting surface to which a high pressure is applied according to the pressure of the working fluid in the housing is controlled, and a mechanism for adjusting the pressing force against the gear side surface of the seal body is realized with a simple configuration. Can do.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view of a gear pump device 10 to which an embodiment of the present invention is applied. FIG. 2 is a cross-sectional view taken along line CC in FIG. Note that the drive gear 30 and the driven gear 32 shown in FIG. 2 are viewed from above.

  The gear pump device 10 according to the present embodiment is provided in each of the drive gear 30 and the driven gear 32 arranged in the housing 12 and meshing with each other, and the drive gear 30 and the driven gear 32. And a case 14 in contact with one side portion 36 (also referred to as “first gear side portion 36”).

  The drive gear 30 has a drive gear shaft portion 31 connected to a drive motor (not shown), and is driven to rotate about the drive gear shaft portion 31 by the drive motor. The driven gear 32 rotates about the driven gear shaft 33 as the drive gear 30 rotates. The drive motor and the drive gear shaft 31 are connected via a joint (not shown).

  As shown in FIG. 1, the case 14 has a cylindrical shape and is in close contact with the first gear side portion 36 of the drive gear 30 or the driven gear 32 to seal the flow of hydraulic oil in the first gear side portion 36. Stop. A case center hole 19 into which the drive gear shaft portion 31 and the driven gear shaft portion 33 are inserted is formed in the center portion of the case 14, and a first pressure action stage provided in a step shape around the entire case center hole 19. A portion 15 and a second pressure acting step portion 17 are formed. The upper surface portion of the first pressure acting step portion 15 constitutes a ring-shaped first pressure acting surface 16, and the upper surface portion of the second pressure acting step portion 17 constitutes a ring-shaped second pressure acting surface 18. The case 14 changes the pressing force against the driving gear 30 or the driven gear 32 according to the pressure applied to the first pressure acting surface 16 and the second pressure acting surface 18, and the first gear of the driving gear 30 or the driven gear 32. The degree of sealing of the distribution of the working oil in the side portion 36 is changed according to the pressing force.

  The housing 12 is formed with a high-pressure side flow path 40 and a low-pressure side flow path 42, which are working oil flow paths. The high pressure side flow path 40 and the low pressure side flow path 42 are arranged at positions via the drive gear 30 and the driven gear 32, and the operating oil is scratched by the rotation of the drive gear 30 and the driven gear 32, and the low pressure side flow path 42. The working oil flows into the high-pressure side passage 40 from above. Therefore, the hydraulic oil in the housing 12 is relatively low pressure hydraulic oil (also referred to as “low pressure hydraulic oil”) flowing in the low pressure side flow path 42 and relatively high pressure hydraulic oil (“high pressure hydraulic oil” flowing in the high pressure side flow path 40. Is also called).

  In the housing 12, a first pressure adjustment oil passage 44 that communicates the high pressure side flow path 40 and the first pressure application surface 16, and a second pressure adjustment oil that communicates the high pressure side flow passage 40 and the second pressure application surface 18. A passage 46 is formed. The second pressure adjusting oil passage 46 branches in the middle and communicates with the low pressure side passage 42 via the first pressure sensitive valve 20. The first pressure sensitive valve 20 adjusts the flow rate of the working oil between the second pressure adjusting oil passage 46 and the low pressure side passage 42. The second pressure adjusting oil passage 46 is provided with a second pressure sensitive valve 22 for adjusting the flow rate of the working oil flowing from the high pressure side passage 40.

  The first pressure sensitive valve 20 and the second pressure sensitive valve 22 have a mechanical structure that operates according to the hydraulic pressure of the working oil in the housing 12. In particular, in the present embodiment, when the pressure of the working oil in the high-pressure side passage 40 reaches a predetermined pressure or higher, the second pressure sensitive valve 22 is opened and the first pressure sensitive valve 20 is closed. On the other hand, when the pressure of the working oil in the high-pressure channel 40 is smaller than a predetermined pressure, the second pressure sensitive valve 22 is closed and the first pressure sensitive valve 20 is opened. An example of the configuration of the first pressure sensitive valve 20 and the second pressure sensitive valve 22 is shown in FIG.

  FIG. 3 is a diagram showing an example of the first pressure sensitive valve 20 and the second pressure sensitive valve 22 having a mechanical structure. Between the high-pressure side passage 40 and the second pressure adjustment oil passage 46 and between the low-pressure side passage 42 and the second pressure adjustment oil passage 46, a hydraulic pressure adjustment cylinder 60 and a hydraulic pressure adjustment piston 62 having a piston-cylinder structure. Is arranged. A high pressure side branch flow path 41 that branches from the high pressure side flow path 40 is connected to one end of the hydraulic pressure adjustment cylinder 60. In the hydraulic pressure adjustment cylinder 60, hydraulic oil flows into the one side of the hydraulic pressure adjustment piston 62 from the high pressure side branch passage 41 and presses the hydraulic pressure adjustment piston 62 to the other side of the hydraulic pressure adjustment piston 62. 64 is arranged. The hydraulic pressure adjusting piston 62 changes the arrangement position in the hydraulic pressure adjusting cylinder 60 based on the balance relationship between the force caused by the working oil flowing from the high pressure side branch flow path 41 and the elastic force of the hydraulic pressure adjusting spring 64.

  For example, when the pressure of the high pressure hydraulic oil flowing into the hydraulic pressure adjustment cylinder 60 from the high pressure side branch passage 41 is relatively high, the hydraulic pressure adjustment piston 62 moves toward the hydraulic pressure adjustment spring 64 against the elastic force of the hydraulic pressure adjustment spring 64. (See arrow A in FIG. 3). When the hydraulic pressure adjustment piston 62 is disposed between the low pressure side flow path 42 and the second pressure adjustment oil path 46, the flow of the working oil between the high pressure side flow path 40 and the second pressure adjustment oil path 46 is ensured. At the same time, the flow of the working oil between the low pressure side flow path 42 and the second pressure adjusting oil path 46 is stopped (see 62 and 64 drawn by the dotted line in FIG. 3). On the other hand, when the pressure of the high pressure hydraulic oil flowing into the hydraulic pressure adjustment cylinder 60 from the high pressure side branch passage 41 is relatively low, the hydraulic pressure adjustment piston 62 is pressed by the hydraulic pressure adjustment spring 64 and moves to the high pressure hydraulic oil side (FIG. 3). Arrow B). When the hydraulic pressure adjustment piston 62 is disposed between the high pressure side flow path 40 and the second pressure adjustment oil path 46, the flow of the working oil between the high pressure side flow path 40 and the second pressure adjustment oil path 46 is stopped. Thus, the flow of the working oil between the low pressure side flow path 42 and the second pressure adjustment oil path 46 is ensured (see 62 and 64 drawn with a solid line in FIG. 3).

  As described above, in the example illustrated in FIG. 3, the first pressure sensitive valve 20 and the second pressure sensitive valve 22 are mechanically configured by the hydraulic pressure adjusting cylinder 60, the hydraulic pressure adjusting piston 62, and the hydraulic pressure adjusting spring 64. The first pressure sensitive valve 20 and the second pressure sensitive valve 22 are opened or closed by the movement of the hydraulic pressure adjustment piston 62 in the hydraulic pressure adjustment cylinder 60 according to the pressure of the high pressure hydraulic oil in the high pressure side flow path 40. The area of the pressure acting surface to which the high pressure is applied is controlled by adjusting the number of pressure acting surfaces to which the high pressure is applied using the high pressure hydraulic oil in the high pressure side flow path 40. When the first pressure sensitive valve 20 is opened and the second pressure sensitive valve 22 is closed, the high pressure working oil flows from the high pressure side passage 40 into the first pressure adjusting oil passage 44 and the first pressure acting surface 16. Although a high pressure is applied to the second pressure acting surface 18, a relatively low pressure is applied to the second pressure acting surface 18 by the low pressure hydraulic oil flowing from the low pressure side passage 42 into the second pressure adjusting oil passage 46. On the other hand, when the first pressure sensitive valve 20 is closed and the second pressure sensitive valve 22 is opened, the high pressure hydraulic oil is transferred from the high pressure side passage 40 to the first pressure adjustment oil passage 44 and the second pressure adjustment oil passage 46. Flows into the second pressure acting surface 18 as well as the first pressure acting surface 16. The first pressure sensitive valve 20 is opened and the second pressure sensitive valve 22 is closed while the high pressure working oil in the high pressure side flow passage 40 is flowing into the second pressure acting surface 18. The pressure of the low-pressure working oil in the low-pressure side flow path 42 acts on the two pressure acting surface 18 to apply a relatively low pressure.

  Note that the movement characteristic of the hydraulic pressure adjusting piston 62 in the hydraulic pressure adjusting cylinder 60 varies depending on the pressure of the high pressure hydraulic oil and the spring characteristics of the hydraulic pressure adjusting spring 64, and therefore flows into the hydraulic pressure adjusting piston 62 from the high pressure side flow path 40, for example. By adjusting the spring constant of the hydraulic pressure adjustment spring 64 according to the pressure of the high-pressure hydraulic oil that is expected to be expected, a desired “movement characteristic of the hydraulic pressure adjustment piston 62” can be obtained. FIG. 3 shows a configuration showing the basic principle, and the actual gear pump device 10 is appropriately modified in accordance with the arrangement state of other parts.

  Further, as shown in FIG. 1, a first annular seal member 24 is provided between the housing 12 and the case 14 in the first pressure adjusting oil passage 44, and between the housing 12 and the case 14 in the second pressure adjusting oil passage 46. Is provided with a second annular seal member 26 to seal between the housing 12 and the case 14.

  Next, the operation of the present embodiment will be described.

  In the gear pump device 10 of the present embodiment, the degree of hydraulic oil circulation sealing in the first gear side portion 36 of the drive gear 30 and the driven gear 32 varies depending on the pressure of the hydraulic oil in the high-pressure side flow path 40. For example, when the pressure of the working oil in the high-pressure side passage 40 is relatively low, the second pressure sensitive valve 22 is closed, and a high pressure is applied to the first pressure acting surface 16 by the working oil and the second pressure acting surface. With the low pressure applied to the case 18, the case 14 is pressed against the first gear side 36 of the drive gear 30 and the driven gear 32. On the other hand, when the pressure of the working oil in the high-pressure side passage 40 is relatively high, the second pressure sensitive valve 22 is opened, and not only the first pressure acting surface 16 but also the second pressure acting surface 18 is caused by the working oil. The case 14 is pressed against the first gear side portion 36 of the drive gear 30 and the driven gear 32 with a strong force.

  Since the degree of hydraulic oil flow sealing in the first gear side portion 36 varies depending on the pressing force of the case 14 against the drive gear 30 and the driven gear 32, the pressure of the hydraulic oil in the high-pressure side passage 40 is low. The higher the case, the higher the degree of hydraulic oil flow sealing at the first gear side 36. Therefore, in the present embodiment, the degree of hydraulic oil circulation sealing in the first gear side portion 36 can be appropriately controlled according to the pressure of the hydraulic oil in the high-pressure side passage 40, and the drive gear 30 and the driven gear can be controlled. The efficiency related to the pressure increase of the working oil generated by the gear 32 and discharged into the high-pressure channel 40 can be kept good (see FIG. 5 described later).

  FIG. 4 is a diagram showing a general relationship between the operating oil pressure in the high-pressure channel 40 (also referred to as “high-pressure operating oil pressure”) and the operating efficiency. The “operation efficiency” here is an index value that directly or indirectly indicates a ratio of “amount of energy consumed when the gear pump device 10 is operated” to “amount of pressure fluctuation of the working oil”. In FIG. 4, type 1 shows the relationship “when the pressing force of the case 14 against the driving gear 30 and the driven gear 32 is small”, and type 2 shows the relationship “the pressing force of the case 14 against the driving gear 30 and the driven gear 32. The relationship of “medium” is shown, and the type 3 shows the relationship of “when the pressing force of the case 14 against the driving gear 30 and the driven gear 32 is large”. As shown in FIG. 4, types 1 to 3 each have a more advantageous range than the other types depending on their characteristics. For example, in the range where the high pressure hydraulic oil pressure is relatively small (see “A” in FIG. 4), type 1 is advantageous in terms of operating efficiency, and in the range where the high pressure hydraulic oil pressure is moderate (see “B” in FIG. 4) 2 is advantageous in terms of operating efficiency, and type 3 is advantageous in terms of operating efficiency in the range where the high-pressure operating oil pressure is relatively large (see “C” in FIG. 4).

  FIG. 5 is a diagram showing the relationship between the high-pressure side hydraulic oil pressure and the operating efficiency (see FIG. 5A) and the diagram showing the relationship between the high-pressure side hydraulic oil pressure and the gear pressing force in the present embodiment. (See FIG. 5B). Here, the “gear pressing force” means the pressing force of the case 14 against the first gear side portion 36 of the drive gear 30 and the driven gear 32. In the present embodiment, in a range where the high pressure hydraulic oil pressure is relatively small (see “A ′” in FIG. 4), the second pressure sensitive valve 22 is closed and high pressure is applied only to the first pressure acting surface 16. The gear pressing force is relatively small. In a range where the high pressure hydraulic oil pressure is relatively large (see “B ′” in FIG. 4), the second pressure sensitive valve 22 is opened and high pressure is applied to the first pressure acting surface 16 and the second pressure acting surface 18. Therefore, the gear pressing force becomes relatively large. As a result, the “relationship between the high-pressure side hydraulic oil pressure and the operational efficiency” becomes a relationship as shown by the solid line in FIG. 5A, and it is possible to ensure an appropriate operational efficiency according to the range of the high-pressure side hydraulic oil pressure.

  As described above, according to the present embodiment, the opening and closing of the first pressure sensitive valve 20 and the second pressure sensitive valve 22 are adjusted according to the pressure of the working oil in the high pressure side passage 40, and the pressure at which high pressure is applied. Since the number and area of the working surfaces are appropriately controlled, the pressing force of the case 14 against the first gear side portion 36 can be controlled to an appropriate magnitude. In particular, in the present embodiment, the number of pressure applied surfaces 16 and 18 that are formed is controlled so that the pressure applied to the case 14 against the first gear side portion 36 is a simple configuration. Therefore, the pressing force can be adjusted to a more appropriate size. As a result, the first gear side portion 36 is properly sealed by the case 14, and energy loss due to frictional force between the case 14, the drive gear 30, and the driven gear 32 can be reduced, and the gear pump is excellent in energy efficiency. The operation of the device 10 can be carried out. Particularly in the present embodiment, the efficient operation of the gear pump device 10 as described above is realized by devising the structural characteristics of the pressure acting portion of the case 14. As described above, according to the present embodiment, efficient pump operation can be performed with a simple mechanical configuration, so that the gear pump device 10 can be provided at a low cost while preventing complication.

  The present invention is not limited to the above-described embodiments, and various modifications such as design changes can be added to the above-described embodiments based on the knowledge of those skilled in the art. Embodiments to which is added can also be included in the scope of the present invention.

  For example, in the above-described embodiment, as shown in FIG. 1, the hydraulic oil flow paths 40 and 42 controlled in pressure by the drive gear 30 and the driven gear 32 are along a plane including the rotation directions of the drive gear 30 and the driven gear 32. However, the present invention is not limited to this. In the gear pump device 10 according to the present invention, it is possible to extend the flow path of the working oil in the housing 12 in an arbitrary direction as long as the above-described object can be achieved. For example, as shown in FIG. 6, the high-pressure side flow path 40 and the low-pressure side flow path 42 can be extended in a direction perpendicular to a plane including the rotation direction of the drive gear 30 and the driven gear 32.

  In the above-described embodiment, the example in which the first pressure-sensitive valve 20 and the second pressure-sensitive valve 22 have the mechanical configuration shown in FIG. 3 has been described. It is also possible to configure the sensitive valve 20 and the second pressure sensitive valve 22. For example, a hydraulic pressure sensor that detects the hydraulic pressure of the working oil in the high-pressure side flow path 40 is provided, and the electromagnetic valves whose opening and closing are controlled based on the detection result of the hydraulic pressure sensor are the first pressure sensitive valve 20 and the second It is also possible to apply to the pressure sensitive valve 22.

  Moreover, although the above-mentioned embodiment demonstrated the example which forms two pressure action surfaces by the two-step structure of the 1st pressure action step part 15 and the 2nd pressure action step part 17, it is not limited to this. . For example, three pressure action surfaces are formed by three or more multistage configurations, or a plurality of pressure action surfaces are formed by dividing a plurality of pressure action surfaces formed by one step portion, or other than stepped structures It is also possible to form a plurality of pressure acting surfaces by this structure. Further, a single pressure acting surface is formed, and an area where a relatively high pressure is applied and an area where a relatively low pressure is applied are controlled in accordance with the pressure of the working oil in the high pressure side flow path 40. By adopting the mechanism, it is possible to control the pressing force of the case 14 against the first gear side portion 36 to an appropriate magnitude.

  In the above-described embodiment, the example in which the first pressure acting surface 16 and the second pressure acting surface 18 are formed in a ring shape has been described, but the case 14 is pressed against the driving gear 30 and the driven gear 32. If possible, any shape such as a semi-ring shape may be used. For example, a pressure acting surface to which high pressure is applied is formed on the high pressure side flow path 40 side through which the high pressure side working oil flows, and the first gear side portion 36 has a higher pressure side flow than the low pressure side flow path 42 through which the low pressure working oil flows. It is also possible to set so that the road 40 side is strongly pressed by the case 14. In this case, although a high pressure is applied to a relatively small pressure acting surface, the high-pressure hydraulic oil in the high-pressure side passage 40 that easily leaks to the first gear side portion 36 of the drive gear 30 and the driven gear 32 is appropriately applied by the case 14. Sealed. As described above, according to the present modification, not only can a high sealing effect be ensured in the first gear side portion 36, but also the amount of energy consumed for pressing the case 14 against the drive gear 30 and the driven gear 32 can be suppressed. be able to.

  Moreover, although the above-mentioned embodiment demonstrated the gear pump, this invention is applicable with respect to the pump apparatus with which a gear is arrange | positioned in a housing. For example, the present invention is also effective for various pumps such as a vane pump that includes a gear that is at least partially in contact with a fluid such as hydraulic oil.

It is sectional drawing of the gear pump apparatus to which one embodiment of this invention is applied. It is sectional drawing of the CC line part of FIG. It is a figure which shows an example of the 1st pressure sensitive valve and 2nd pressure sensitive valve which have a mechanical structure. It is a figure which shows the general relationship of the pressure of the working oil in a high voltage | pressure side flow path (it is also called "high pressure side working oil pressure"), and operating efficiency. (A) is a figure which shows the relationship between the high voltage | pressure side hydraulic oil pressure in one embodiment of this invention, and operating efficiency, (b) is the high voltage | pressure side hydraulic oil pressure and gear pushing in one embodiment of this invention. It is a figure which shows the relationship of application force. It is a figure which shows the gear pump apparatus of one modification of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Gear pump apparatus, 12 Housing, 14 Case, 15 1st pressure action step part, 16 1st pressure action surface, 17 2nd pressure action step part, 18 2nd pressure action surface, 19 Case center hole, 20 1st pressure sensitivity Valve, 22 second pressure sensitive valve, 24 first annular seal member, 26 second annular seal member, 30 drive gear, 31 drive gear shaft portion, 32 driven gear, 33 driven gear shaft portion, 36 first gear side portion, 37 second gear side, 40 high pressure side flow path, 41 high pressure side branch flow path, 42 low pressure side flow path, 44 first pressure adjustment oil path, 46 second pressure adjustment oil path, 60 hydraulic pressure adjustment cylinder, 62 hydraulic pressure adjustment Piston, 64 Hydraulic adjustment spring.

Claims (5)

A pump device comprising a gear arranged in a housing,
A pressure acting portion including at least one pressure acting surface, the pressing force against the side of the gear is changed according to the pressure applied to the pressure acting surface, and the working fluid is sealed in the side of the gear. A sealing body that changes the degree of stopping according to the pressing force;
Pressure adjusting means for controlling the area of the pressure acting surface to which a high pressure is applied according to the pressure of the working fluid in the housing;
A pump device comprising: The pressure acting part has a plurality of pressure acting surfaces,
2. The pump device according to claim 1, wherein the pressure adjusting unit controls the number of the pressure acting surfaces to which a high pressure is applied in accordance with the pressure of the working fluid in the housing.   The pump device according to claim 1, wherein the pressure adjusting unit applies a high pressure to the pressure acting surface using a working fluid in the housing. The seal body has at least one step portion constituting the pressure acting portion,
The pump device according to claim 1, wherein the pressure acting surface is constituted by the stepped portion. The working fluid in the housing is divided into a low pressure working fluid and a high pressure working fluid through the gear,
The pressure adjusting means is configured to apply the high pressure so that the side of the high pressure working fluid side of the side of the gear is pressed more strongly by the seal body than the side of the low pressure working fluid side. The pump device according to any one of claims 1 to 4, wherein the area of the pump is controlled.

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