JP5222758B2 - Gear pump - Google Patents

Description

  The present invention relates to a gear pump.

  Conventionally, the technique of patent document 1 is well-known as a gear pump. According to this invention, the driven gear is fixed so as to be relatively rotatable so that the driven shaft has a function of a sliding bearing.

JP 2002-31065 A

  However, in the conventional invention, if the diameter of the driven shaft is reduced or the driven gear (both the drive gear) is thinned for the purpose of reducing the size of the gear pump, the sliding resistance between the driven shaft and the driven gear increases. There was a problem of end.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a gear pump capable of realizing downsizing of the gear pump and reduction of manufacturing cost.

According to the first aspect of the present invention, there is provided an external gear pump including at least two gears meshing with each other , and a drive shaft and a driven shaft for driving each of the gears . The front end is provided with a fitting convex portion or a fitting concave portion that can be fitted with the front end of the drive motor, and the driving shaft and the driven shaft are provided with convex portions capable of driving the corresponding gears, respectively. Each gear is provided with a concave portion that can be fitted to the corresponding convex portion of the drive shaft and the convex portion of the driven shaft at a common position, and is provided at the tip of the drive shaft when the gear pump is assembled. By aligning the direction of the convex portion or concave portion with the convex portion of the driven shaft, the convex portion of the drive shaft and the convex portion of the driven shaft are set to a position having a predetermined phase difference. engaged to fitting of the concave portion to the convex portion And wherein the door.

  According to the first aspect of the present invention, the driven shaft and the driven gear are prevented from rotating by the convex portion and the concave portion, and no sliding resistance is generated between them. The gear pump can be miniaturized.

It is a front view of the gear pump of Example 1. It is sectional drawing in the A2-A2 line | wire of FIG. FIG. 3 is an enlarged view of a main part of FIG. 2. It is a principal part expanded sectional view in the A4-A4 line of FIG. 2 is a front perspective view of a seal member of Example 1. FIG. 3 is a front view of a seal member of Example 1. FIG. FIG. 3 is a front perspective view of a first side plate according to the first embodiment. FIG. 3 is a front perspective view of a first side plate according to the first embodiment. FIG. 6 is a rear view of the first side plate according to the first embodiment. It is a figure explaining arrangement | positioning of the 1st side plate of Example 1, and a 1st gear. It is a figure explaining (a) before the connection of the gear pump and motor of Example 1, and (b) after connection. It is a figure explaining arrangement | positioning of the sealing member of Example 1, a 1st side plate, and a 1st gear. It is sectional drawing in the A13-A13 line | wire of FIG. It is a figure explaining arrangement | positioning of the drive convex part of the drive shaft of Example 1, and the driven pin of a driven shaft. It is a figure explaining arrangement | positioning of the drive convex part of the drive shaft of Example 2, and the driven pin of a driven shaft. It is sectional drawing explaining the rotation prevention of the driven shaft and driven gear of Example 3. It is a figure explaining the rotation prevention of the driven shaft and driven gear of Example 3. FIG.

  Embodiments of the present invention will be described below with reference to the drawings.

Example 1 will be described below.
As shown in FIGS. 1 and 2, the gear pump 1 of the first embodiment is used for an actuator for controlling the brake fluid pressure of an automobile, and includes a housing 2 and a pump assembly 3 accommodated in the housing 2. Is provided.

[About housing]
Next, the housing 2 will be described. The housing 2 is formed in a substantially rectangular shape, and a plurality of mounting holes 2a to which a switching valve and a sensor (not shown) are attached are formed on the outer surface. A pump chamber 4 that is recessed in a substantially cylindrical shape with steps having different diameters is formed in the approximate center of the front surface of the housing 2, and the pump assembly 3 is accommodated therein.

[About pump assembly]
Next, the pump assembly 3 will be described. In addition, the opening end side (the 2nd pump 9 side mentioned later) of the pump chamber 4 is set as the front, and the bottom part side (the 1st pump 8 side mentioned later) of the pump chamber 4 is described as the back. As shown in FIGS. 3 and 4, the pump assembly 3 includes a plug member 5, a cover member 6, a seal member 7, a first pump 8 and a second pump 9. The plug member 5 is formed in a substantially disk shape, and a through hole 5a formed in a hexagonal column shape is formed at the center thereof. The rear end of the plug member 5 is formed with a rear surface 5d that comes into contact with a cover member 6 to be described later, and an annular protrusion 5b that surrounds the outer periphery of the rear surface 5d and projects annularly rearward. Further, a male screw groove 5 c is formed on the outer periphery of the plug member 5. The male screw groove 5 c is screwed into a female screw groove 4 a formed in the inner peripheral portion of the pump chamber 4. The cover member 6 is formed in a substantially disk shape, and has a front surface 6e that comes into contact with the plug member 5 and a step portion 6f cut out over the entire outer periphery of the front surface 6e. Then, the front surface 6e is pressed backward by the axial force generated by the screwing of the plug member 5, so that the front surface 6e comes into contact with the rear surface 5d of the plug member 5, and further, the annular protrusion 5b and the step portion 6f of the plug member 5 are contacted. Are arranged at predetermined positions in a state of being fitted. On the outer periphery of the cover member 6, a convex portion 6 g having a height substantially the same as that of the inner periphery of the pump chamber 4 and substantially the same radial height as the annular protrusion 5 b is formed. Further, a seal groove 6h is formed on the outer periphery of the cover member 6 and behind the convex portion 6g. An annular seal S1 is provided between the convex portion 6g and the annular protrusion 5b to ensure sealing performance with the inner periphery of the pump chamber 4, and the seal groove 6h is provided with the inner periphery of the pump chamber 4. An annular seal S2 is provided to ensure sealing performance. That is, the seals S1 and S2 are mounted at positions separated from each other in the front-rear direction. At the eccentric position of the cover member 6, a stepped through hole 6 b having a different inner diameter is formed. The drive shaft 10 is inserted into the through hole 6b with a gap 6a. On the other hand, annular seals S3 for securing the sealing performance with the drive shaft 10 are respectively mounted on the large diameter side and the small diameter side of the through hole 6b. Further, a recess 6d that is annularly formed forward and an annular protrusion 6c that protrudes annularly rearward from the recess 6d is formed at the rear end of the cover member 6. On the inner periphery of the annular protrusion 6c, a step portion 6i is formed that is cut out over the entire inner periphery.

  As shown in FIGS. 5 and 6, the seal member 7 is formed in a substantially disk shape, and in the drawing, the two through holes 7 a and 7 b have a circular opening cross section in the front-rear direction. It is formed through. Further, side seal portions 7d protruding in the axial direction along the peripheries of the through holes 7a and 7b are formed on the front and rear surfaces of the seal member 7, respectively, and a pair of engagement convex portions 7e are formed on one side surface thereof. It protrudes to the side. Each side seal portion 7d is formed with a ring accommodating portion 7f that is coaxially formed with the through-hole 7a and is annularly recessed inward in the thickness direction. Further, on the inner side in the thickness direction of the ring housing portion 7f on the rear surface of the seal member 7, a small-diameter seal housing portion 7g that is continuously annularly recessed with the ring housing portion 7f is formed. In addition, on the outer periphery of the seal member 7, a seal receiving groove 7 h that is annularly recessed radially inward is formed, and an annular protrusion 7 i that is annularly protruded forward is formed at the front end thereof. .

  As shown in FIGS. 3 and 4, the seal member 7 is pressed rearward through the cover member 6 by the axial force generated by the screwing of the plug member 5. As a result, the annular protrusion 7i of the seal member 7 is fitted into the step 6i of the cover member 6, and further, a part of the rear surface thereof is disposed at a predetermined position in contact with the step 4b of the pump chamber 4. (Positioning). The drive shaft 10 is inserted into the through hole 7a of the seal member 7, while the driven shaft 11 is inserted into the through hole 7b. An annular rotary seal member 12 (X ring or the like) is interposed in the seal housing portion 7g of the seal member 7, and a sealing property between the drive shaft 10 and a first pump chamber P1 described later is ensured. Further, a first seal ring 13 a is interposed in the ring housing portion 7 f on the rear surface of the seal member 7 in a state where the seal housing portion 7 g of the rotary seal member 12 is closed. An annular second seal ring 13b is interposed in the front ring accommodating portion 7f. Each of the seal rings 13a and 13b is formed of a material that is harder and more durable than at least the seal member 7. The seal housing groove 7h of the seal member 7 is fitted with an annular seal S4 that is in close contact with the inner periphery of the pump chamber 4 and ensures a sealing property between the first pump chamber P1 and the second pump chamber P2. Has been. A first pump chamber P1 serving as a closed space is formed between the seal member 7 and the recess 4c that is annularly recessed rearward from the step 4b of the pump chamber 4, and the first pump 8 is provided here. It is arranged. On the other hand, between the recessed part 6d of the cover member 6 and the sealing member 7, the 2nd pump chamber P2 used as a closed space is formed, and the 2nd pump 9 is arrange | positioned here. The first pump 8 is provided with a first gear 15 whose front and rear surfaces and tooth tips are sealed by a seal member 7 and a first side plate 14 described later. First, the first side plate 14 will be described. As shown in FIGS. 7 to 9, the first side plate 14 is made of resin and has a substantially triangular shape in front view. Also, three through holes 14a, 14b, 14c are formed in the vicinity of the apex of the substantially triangular shape. On the front surface of the first side plate 14, a side seal portion 14d protruding forward is formed around the through holes 14a and 14b. In addition, a seal block 14e protruding forward in a substantially triangular shape is formed on the front surface of the first side plate 14. The seal block 14e has a passage portion 14f that forms an opening toward the center continuously from the through-hole 14c, and a pair that is formed on both sides of the passage portion 14f and continues to a part of the side seal portion 14d. Are formed with a curved surface tooth tip seal portion 14g and an engagement portion 14h located on the front side of each tooth tip seal portion 14g. Further, the seal block 14e is formed with a groove 14i that is recessed inward from the outer periphery of the tooth tip seal portion 14g so as to surround the through hole 14c. On the other hand, on the rear surface of the first side plate 14 (see FIG. 9), a seal accommodation groove 14j bent into a substantially triangular shape is provided so as to surround each through hole.

  As shown in FIG. 4, the drive shaft 10 is rotatably inserted into the through hole 14 a of the first side plate 14 with a predetermined gap in the radial direction. On the other hand, the driven shaft 11 is inserted into the through hole 14b with a predetermined gap in the radial direction. Further, a seal S5 is interposed in the seal housing groove 14j, and the sealing performance between the low pressure side and the high pressure side of the first pump chamber P1 is ensured.

  Next, the first gear 15 will be described. As shown in FIG. 10, the first gear 15 is composed of a drive gear 16 through which the drive shaft 10 is inserted and a driven gear 17 through which the driven shaft 11 is inserted, and the tooth tips 16a, The teeth 17a are meshed with each other at the meshing portion 18. A concave portion 10a that is recessed inward is formed at a position corresponding to the drive gear 16 in the drive shaft 10, and the distal end side of a cylindrical drive pin 10b extending in the radial direction from the axis of the drive shaft 10 is inserted here. Has been. The base end side of the drive pin 10 b is engaged with a recess 16 b formed in the inner periphery of the drive gear 16. On the other hand, a recessed portion 11a that is recessed inward is formed at a position corresponding to the driven gear 17 on the driven shaft 11, and the tip of a cylindrical driven pin 11b that extends radially from the axis of the driven shaft 11 is formed here. The side is inserted. The base end side of the driven pin 11 b is engaged with a recess 17 b formed in the inner periphery of the driven gear 17. Further, as shown in FIGS. 11A and 11B, a front surface of the drive shaft 10 is formed with a fitting convex portion 19 having a two-surface width, while the rotation shaft 20a of the motor M1 (drive source). A fitting recess 20b that can be engaged with the fitting protrusion 19 and connected to the rotary shaft 20a is formed at the distal end portion. Thus, the drive shaft 10 is configured to be rotationally driven in the direction around the shaft by driving the motor M1. Further, since the drive gear 16 is prevented from rotating around the drive shaft 10 by engagement with the drive pin 10b, the drive gear 16 rotates in the same rotational direction as the drive shaft 10 as the drive shaft 10 rotates. On the other hand, the driven gear 17 meshed with the drive gear 16 is prevented from rotating around the driven shaft 11 by the engagement with the driven pin 11b, and thus rotates together with the driven shaft 11 in the direction opposite to the drive shaft 10.

  As shown in FIG. 10, the tooth tips 16a and 17a of the gears 16 and 17 are slidable in liquid-tight contact with the corresponding tooth tip seal portions 14g of the seal block 14e of the first side plate 14. Yes. Further, as shown in FIGS. 12 and 13, the pair of engaging convex portions 7e on the rear surface of the seal member 7 are engaged in close contact with the curved surfaces of the corresponding engaging portions 14h of the seal block 14e. The tooth tips 16a and 17a of the gears 16 and 17 are sealed with the side seal portion 14d of the first side plate 14. Further, a holding member 21 is mounted in a substantially triangular shape so as to be hung on a corresponding side seal portion 7d of the seal member 7 and a groove 14i formed on the outer periphery of the seal block 14e (see FIG. 4). Although not shown, the pump chamber 4 is provided with a suction port that communicates with the through hole 14c of the first side plate 14 and a discharge port that communicates with the first pump chamber P1. On the other hand, the second pump 9 has a symmetrical configuration with the first pump 8 around the seal member 7. That is, the second gear 23 whose front and rear surfaces are sealed by the seal member 7 and the second side plate 22 is disposed. Since the second side plate 22 and the second gear 23 have the same shape as the first side plate 14 and the first gear 15 in the left-right symmetry, the description thereof is omitted.

  As shown in FIG. 4, the drive shaft 10 is rotatably inserted into the through hole 22a of the second side plate 22 with a predetermined gap in the radial direction, while the driven shaft is inserted into the through hole 22b. 11 is inserted in a state having a predetermined gap in the radial direction. Further, a seal S6 is interposed in the seal housing groove 22j, and the sealing performance between the high pressure side and the low pressure side of the second pump chamber P2 is ensured.

  In addition, in the second pump 9, the pump chamber 4 is provided in the second side plate 22 through a through hole (not shown) corresponding to the above-described through hole 14 c of the first side plate 14 and an oil passage of the cover member 6. The first pump 8 is substantially the same as the first pump 8 except that a suction port (not shown) communicated to the second pump chamber P2 via an oil passage formed in the cover member 6 is provided. It is a configuration. The diameters of the through holes 14a and 22a of the side plates 14 and 22 are set larger than the diameter of the drive shaft 10, and the diameters of the through holes 14b and 22b are set larger than the diameter of the driven shaft 11. . That is, the drive shaft 10 and the driven shaft 11 are inserted through the through holes 14a and 22a and the through holes 14b and 22b of the corresponding side plates 14 and 22, respectively, through a slight gap.

[Phase relationship between drive gear and driven gear]
Next, the phase relationship between the drive gear 16 and the driven gear 17 of the first gear 15 and the phase relationship between the drive gear 26 and the driven gear 27 of the second gear 23 will be described. Since both gears 15 and 23 have the same configuration, only the phase relationship between the drive gear 26 and the driven gear 27 in the second gear 23 will be illustrated and described. As shown in FIG. 14, both gears 26 and 27 of the second gear 23 are composed of identically shaped parts having recesses 26b and 27b at a common position, and are assembled to each other with a phase shifted by an angle α. In addition, the longitudinal direction L1 of the fitting projection 19 of the drive shaft 10 (hereinafter referred to as the arrangement direction L1 of the fitting projection 19) and the protruding direction L2 of the driven pin 11d (hereinafter, the arrangement direction of the driven pin 11d). L2) is set at an equal angle in the 0 degree direction. When the number of teeth of each gear 26 and 27 is z, the following expressions (1) and (2) are established for the angle α between the arrangement direction L1 of the fitting protrusion 19 and the protruding direction of the drive pin 10e. ing.
α = 360 / 2z = 180 / z (1)
(2n-1) α <360 (n = 1, 2, 3...) (2)
In the first embodiment, the gears 26 and 27 have 18 teeth and α is set to 10 degrees, but this value can be set as appropriate and is not limited to this.

Next, the operation of the first embodiment will be described.
[Assembly of gear pump]
Next, assembly of the gear pump 1 will be described. When assembling the gear pump 1 configured as described above, first, the rotary seal member 12 is inserted and temporarily fixed in the seal accommodating portion 7g of the seal member 7 to which the seal S4 is previously attached. Next, the drive shaft 10 is inserted into the through hole 7a of the seal member 7, while the driven shaft 11 is inserted into the through hole 7b. Next, the seal rings 13a and 13b respectively corresponding to the ring accommodating portions 7f of the seal member 7 are inserted. At this time, when the rotary seal member 12 is pressed by the first seal ring 13 a, the rotary seal member 12 is in good contact with the drive shaft 10. Next, the drive pins 10b and 10e and the driven pins 11b and 11d are inserted into the corresponding recesses 10a and 10d of the drive shaft 10 and the recesses 11a and 11c of the driven shaft 11, respectively. Next, the drive gears 16, 26 and the driven gears 17, 27 are assembled to the corresponding drive shaft 10 and the driven shaft 11, respectively.

[Assembly of drive gear and driven gear]
Here, the gears 16, 26, 17, and 27 are assembled to the corresponding shafts 10 and 11, respectively. At this time, the drive gears 16 and 26 and the driven gears 17 and 27 are connected to the gears 15 and 23, respectively. It is necessary to avoid collision in the thickness direction when combining. That is, if the relative rotation angle between the drive gears 16 and 26 and the driven gears 17 and 27 to be engaged with each other is not set to the angle α, the engagement cannot be achieved. Therefore, it is conceivable that the angle α is set by the drive pins 10b and 11b and the driven pins 11b and 11d. However, the angle α is an angle that is difficult to set visually by the operator (10 degrees in the first embodiment). As a result, the actual work becomes difficult. On the other hand, in the first embodiment, the drive gears 16 and 26 and the driven gears 17 and 27 are simply aligned with the arrangement direction L1 of the fitting convex portion 19 and the arrangement direction L2 of the driven pins 11b and 11d in the 0 degree direction. The relative rotation angle can be easily set to the angle α by visual observation. Therefore, it is possible to avoid collision in the thickness direction when the drive gears 16 and 26 and the driven gears 17 and 27 are engaged with each other, and the assemblability of the gears 16, 26, 17, and 27 can be improved.

(Assembly example 1)
For example, as an assembly example 1, first, the driven gears 11 and 27 are assembled to the driven shaft 11 by engaging the recesses 17b and 27b of the driven gears 17 and 27 of the driven pins 11b and 11d of the driven shaft 11. Next, the recesses 16b and 26b of the drive gears 16 and 26 are engaged with the drive pins 10b and 10e of the drive shaft 10, and the drive gears 16 and 26 are assembled to the drive shaft 10. At this time, the fitting protrusion 19 And the arrangement direction L2 of the driven pins 11b and 11d are made to coincide with the 0 degree direction. As a result, the drive gears 16 and 26 can be engaged with the corresponding driven gears 17 and 27 without colliding in the thickness direction. The same operation and effect can be obtained by assembling the driven gears 17 and 27 to the driven shaft 11 after the drive gears 16 and 26 are assembled to the drive shaft 10.

(Assembly example 2)
As an assembly example 2, first, the driven gear 27 is assembled to the driven shaft 11 by engaging the recess 27 b of the driven gear 27 with the driven pin 11 d of the driven shaft 11. Next, the recess 26b of the drive gear 26 is engaged with the drive pin 10e of the drive shaft 10 and the drive gear 26 is assembled to the drive shaft 10. At this time, the arrangement direction L1 of the fitting protrusion 19 and the driven pin 11d The arrangement direction L2 is made to coincide with the 0 degree direction. Thereby, the drive gear 26 can be meshed with the driven gear 27 without colliding in the thickness direction. Note that the driven gear 27 may be assembled to the driven shaft 11 after the drive gear 26 is assembled to the drive shaft 10. Next, after the recess 16b of the drive gear 16 is engaged with the drive pin 10b of the drive shaft 10 and the drive gear 16 is assembled to the drive shaft 10, the recess 17b of the driven gear 17 is engaged with the driven pin 11b. The driven gear 17 is assembled to the driven shaft 11. At this time, since the relative rotational angles of the shafts 10 and 11 have already been determined by the engagement of the drive gear 26 and the driven gear 27 in the previous process, the driven gear 17 is not caused to collide with the drive gear 16 in the thickness direction. Can be combined. The same operation and effect can be obtained by assembling the driven gear 17 to the driven shaft 11 after the drive gear 16 is assembled to the drive shaft 10. Thus, in the first embodiment, when the drive gears 16 and 26 and the driven gears 17 and 27 are assembled, the fitting protrusion 19 provided at the tip of the drive shaft 10 and the driven pins 11b and 11d of the driven shaft 11 Positioning of the gears 16, 17, 26, and 27 can be easily performed by visual observation, and assemblability can be improved.

[About sharing of driven shaft]
In addition, when the driven gears 17 and 27 are provided with independent driven shafts, the number of positioning steps increases, whereas in the first embodiment, the driven gears 17 and 27 share the driven shaft 11. Therefore, the assembly efficiency can be improved and the number of parts can be reduced to reduce the manufacturing cost.

  Subsequently, after the drive gears 16 and 26 and the driven gears 17 and 27 are assembled, the drive shaft 10 and the driven shaft 11 are inserted into the side plates 14 and 22 on which the seals S5 and S6 and the holding members 21 and 23 are mounted in advance. And assembled to the seal member 7. At this time, on the first side plate 14 side of the seal member 7, the pair of engaging convex portions 7 e are engaged with the corresponding engaging portions 14 h of the first side plate 14, so that both of them are positioned. Can be assembled easily. In addition, the holding member 21 can fix the seal member 7 and the first side plate 14 in a temporarily held state. In addition, the holding member 21 can be attached to the seal member 7 in advance, and then the diameter can be expanded and hung on the first side plate 14. Similarly, on the second side plate 22 side, the pair of engaging convex portions 7e of the seal member 7 are engaged with the corresponding engaging portions 22g of the second side plate 22 so that both of them are positioned. Can be assembled easily. In addition, the holding member 24 can fix the seal member 7 and the first side plate 14 in a temporarily held state. Further, the holding member 23 can be attached to the seal member 7 in advance, and then the diameter can be expanded and hung on the second side plate 22, so that the mounting property is good.

  Next, the drive shaft 10 is inserted into the through-hole 6a of the cover member 6 on which the seals S1 and S2 are mounted in advance, and the annular protrusion 6c of the cover member 6 is fitted to the seal member 7 so that the cover member 6 is inserted. Assembling the seal member 7, the pump assembly 3 is assembled.

  Next, after inserting the pump assembly 3 assembled in this way into the pump chamber 4 of the housing 2, the plug member 5 is screwed into the pump chamber 4 and fixed. At this time, the sealing member 7 can be brought into close contact with the step portion 4b of the pump chamber 4 by the axial force generated by the screwing of the plug member 5 and can be fixed in a stable state, and the positions of the respective members in the front-rear direction can be accurately arranged. It is possible to prevent rattling caused by fluctuations in the pressure of the operating oil. In addition, when the seal S <b> 1 is pressed against the annular protrusion 5 b of the plug member 5, the sealing performance between the pump chamber 4 and the cover member 6 is improved. Thus, in the gear pump 1 of Example 1, the pump assembly 3 can be accommodated in the housing 2 in a temporarily assembled state, and the assembling work can be simplified.

[Connection between gear pump and motor]
As shown in FIGS. 11 (a) and 11 (b), the gear pump 1 configured in this manner has a fitting convex portion 19 that is cut out in the shape of a long hole in cross section at the tip of a cylindrical drive shaft 10. It connects with the fitting recessed part 20b of the rotating shaft 20a of M1. Under the present circumstances, the cross-sectional longitudinal direction of the fitting recessed part 20b is preset to the 0 degree direction equal to the arrangement direction L1 of the fitting convex part 19. As shown in FIG. Therefore, the shafts 10 and 19 can be connected by the operation of relatively moving the drive shaft 10 and the rotary shaft 20a in the axial direction, and the gear pump 1 and the motor M1 can be easily connected. In addition, you may reverse the uneven | corrugated shape of the fitting convex part 19 and the fitting recessed part 20b.

[About operation of gear pump]
Next, the operation of the gear pump 1 will be described. As shown in FIG. 10, when the drive shaft 10 is driven to rotate in the direction of the arrow in the drawing by driving the motor M <b> 1, the driven gear 17 is driven via the drive gear 16 in the first pump 8. By this action, low-pressure hydraulic oil is introduced from the through hole 14c of the seal block 14e of the first side plate 14 communicating with the suction port, and high-pressure hydraulic oil is output to the pump chamber P1. This high pressure hydraulic oil is output from the corresponding discharge port. Further, in the second pump 9, similarly to the first pump 8, the driven gear 18 b is driven via the drive gear 18 a, thereby penetrating the second side plate 22 corresponding to the through hole 14 c of the first side plate 14. Low pressure (negative pressure) hydraulic oil is introduced from a hole (not shown), and high pressure hydraulic oil is output to the pump chamber P2. This high pressure hydraulic oil is output to the corresponding discharge port. In this way, the gear pump 1 performs suction and discharge of hydraulic oil in different piping systems in both pump chambers P1 and P2, and functions as a so-called tandem external gear pump. Normally, the hydraulic fluid of the first piping system introduced into the first pump chamber P1 corresponds to either the left front wheel and the right rear wheel or the right front wheel and the left rear wheel of the automobile. The hydraulic fluid of the second piping system introduced into the pump chamber P2 corresponds to the other of the left front wheel and the right rear wheel or the right front wheel and the left rear wheel of the automobile.

[Gear sharing]
As described above, since the drive gears 16 and 27 and the driven gears 26 and 27 are composed of the same shape parts and are assembled with each other with the phase shifted by an angle α, all the gears 16, 17, 26, and 27 are combined into one type. It can be shared by parts, reducing manufacturing costs and eliminating assembly errors.

[About downsizing and weight reduction of gear pump]
As described above, since the gears 16, 26, 17, and 27 are respectively prevented from rotating around the corresponding drive shaft 10 and driven shaft 11, no sliding resistance is generated between them. As a result, the diameter of the driven shaft 11 can be reduced and the driven gears 17 and 27 (both the drive gears 16 and 26) can be thinned, and the gear pump 1 can be reduced in size and weight. In the case of a tandem external gear pump as in the first embodiment, since the two gears 15 and 23 are arranged side by side and are particularly easy to increase in size, the effect of reduction in size and weight is great and suitable.

Finally, the effect of Example 1 is listed with (1)-(3) corresponding to Claims 1-3.
(1) A drive gear 16, 26 and driven gears 17, 27 are provided, and a drive shaft 10 and a driven shaft 11 for driving the drive gears 16, 26 and the driven gears 17, 27 are rotatably mounted. In the gear pump 1, the drive shaft 10 and the driven shaft 11 are provided with drive pins 10b and 10e and driven pins 11b and 11d, respectively, which can drive the corresponding drive gears 16 and 26 and driven gears 17 and 27, respectively. The gears 16 and 26 and the driven gears 17 and 27 have the same recesses 16b, 17b, 26b, and 27b that can be fitted to the corresponding drive pins 10b and 10e of the drive shaft 10 and the driven pins 11b and 11d of the driven shaft 11, respectively. The drive gears 16 and 26 and the driven gears 17 and 27 are assembled to each other while shifting the phases of the recesses 16b, 17b, 26b, and 27b. Thereby, size reduction of the gear pump 1 and reduction of manufacturing cost are realizable.

  (2) A fitting projection 19 that can be fitted to the drive motor M1 is provided at the tip of the drive shaft 10, and a fitting projection 19 provided at the tip of the drive shaft 10 is provided at the tip of the drive motor M1. And when the gear pump 1 is assembled, the drive gears 16 and 26 and the driven gear are driven by the fitting convex portion 19 provided at the tip of the drive shaft 10 and the fitting concave portion 20b of the driven shaft 10 when the gear pump 1 is assembled. The gears 17 and 27 are positioned. Thereby, at the time of the assembly of the gear pump 1, the contact of the drive gears 16 and 26 and the driven gears 17 and 27 in the thickness direction can be avoided, and the assembling property can be improved.

  (3) When the gear pump 1 and the drive motor M1 are assembled, the fitting convex portion 19 provided at the tip of the driving shaft 10 and the fitting concave portion 20b of the driving motor M1 are positioned. Thereby, the gear pump 1 and the motor M1 can be easily connected.

Example 2 will be described below.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, the description thereof will be omitted, and only the differences will be described in detail.

  As shown in FIG. 15, the invention of the second embodiment is different from the first embodiment in that the arrangement direction L <b> 1 of the fitting convex portion 19 described in the first embodiment is a 90-degree direction. Accordingly, the positioning of the gears 16, 17, 26, and 27 can be easily performed by setting the direction in which the arrangement direction L1 of the fitting projection 19 and the arrangement direction L2 of the driven pins 11b and 11d of the driven shaft 11 are orthogonal to each other. The same actions and effects as those of the first embodiment can be obtained.

Example 3 will be described below.
In the third embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, the description thereof will be omitted, and only differences will be described in detail. As shown in FIGS. 16 and 17, in the invention of the third embodiment, the drive gear 26 and the driven gear 27 are coupled to the corresponding shafts 10 and 11 by serration grooves 30 and 31 formed respectively. . In addition, since the structure of the drive gear 16 and the driven gear 27 and the shafts 10 and 11 is the same, the illustration explanation is omitted. Accordingly, the gears 16, 26, 17, and 27 can be prevented from rotating on the corresponding driven shaft 10 and the driven shaft 11, respectively, and at the same time, the phases of the drive gears 16, 26 and the driven gears 17, 27 can be positioned. The same actions and effects can be obtained.

Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and design changes and the like within the scope not departing from the gist of the present invention are included in the present invention.
For example, when the rotation direction of the drive shaft described in the embodiment is reversed, it goes without saying that the hydraulic oil flows from the discharge port side toward the suction port side. The gear pump is not limited to a tandem external gear pump, and can be employed in a single external gear pump similar to that of the invention described in Patent Document 1, and a gear pump having other driven shafts and driven gears. Furthermore, it is possible to provide independent driven shafts for the driven gears.

DESCRIPTION OF SYMBOLS 10 Drive shaft 10b, 10e Drive pin 11 Drive shaft 11b, 11d Drive pin 16b, 17b, 26b, 27b Recessed part 17, 27 Drive gear

Claims (2)

A circumscribed gear pump comprising at least two gears meshing with each other, and a drive shaft and a driven shaft for driving each of the gears are rotatably mounted,
The front end of the drive shaft is provided with a fitting convex part or a fitting concave part that can be fitted with the tip of the drive motor,
The drive shaft and the driven shaft are provided with convex portions capable of driving the corresponding gears, respectively.
Each of the gears is provided with a concave portion that can be fitted to the corresponding convex portion of the drive shaft and the convex portion of the driven shaft at a common position.
When the gear pump is assembled, the convex portion of the drive shaft and the convex portion of the driven shaft are aligned by aligning the direction of the convex portion or concave portion provided at the tip of the drive shaft with the convex portion of the driven shaft. A gear pump characterized in that the concave portion of each gear is fitted to the convex portion . The gear pump according to claim 1, wherein
A gear pump characterized in that, when the gear pump and the drive motor are assembled, a convex portion or a concave portion provided at the tip of the drive shaft and a concave portion or a convex portion of the drive motor are positioned .

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