JP5441873B2 - External gear pump - Google Patents

Description

  The present invention relates to an external gear pump that is suitable not only for use in a hydraulic source such as a hydraulic device but also for boosting a low-viscosity fluid such as gasoline or brake fluid.

  As background art of the present invention, there are, for example, Patent Document 1 and Patent Document 2.

  Patent Document 1 discloses that a pair of gears that are supported by their respective rotating shafts and circumscribing each other, a side plate that is provided in sliding contact with the side surfaces of the pair of gears, and the gears that are close to each other from some directions. And a seal block that contacts and seals the side plate, and a pump assembly that drives one of the rotating shafts, a casing that houses the pump assembly, and a shaft that is fixed to the casing and that supports the rotating shaft. An external gear pump comprising: a bearing that is configured to restrict movement of the seal block in a plane perpendicular to a rotation axis with respect to a component integral with the casing. Yes.

  Patent Document 2 discloses at least one of a pump assembly including a gear driven by a drive shaft, a pair of side plates that suppress leakage of hydraulic fluid from the side surface of the gear, and a tooth tip seal member that seals the tooth tip. A gear pump in which the side plate and the tooth tip seal member are integrally formed is disclosed.

JP 2010-31771 A JP 2010-121447 A

  In the external gear pump described in Patent Document 1, one side surface of the gear is configured to slide on a plurality of members such as a casing as a pressure vessel and a bearing portion, and the material is not suitable for sliding. In some cases, the sliding resistance increases.

  On the other hand, the external gear pump described in Patent Document 2 needs to be designed to allow a sufficient part strength in order to prevent deformation of the seal block when subjected to pressure.

  An object of the present invention is to provide an external gear pump that can achieve both sealing performance and slidability and is advantageous in terms of manufacturing cost.

  In order to solve the above problems, an external gear pump of the present invention includes a casing, a pair of rotary shafts supported by bearings provided in the casing, and a pair of rotary shafts that are fixed to the pair of rotary shafts and circumscribed with each other. At least a pair of gears meshing with each other, a side plate provided in sliding contact with one side surface of the pair of gears, a side sliding portion sliding in contact with the other side surface of the pair of gears, and a tooth tip of the gear A seal block integrally formed with a tooth tip sliding portion that seals, and provided with movement restriction means on both sides of a straight line connecting the shafts of the pair of gears, the seal block, The movement of the casing is restricted within a plane orthogonal to the rotation axis.

  According to the present invention, a material suitable for the sliding surface can be selected and the deformation of the sealing block can be reduced by forming the seal block integrally formed with the side surface sliding portion and the tooth tip seal portion of the gear. Therefore, it is possible to provide an external gear pump that can achieve both sealing performance and sliding performance.

  In addition to the above effects, the present invention provides an external gear pump that can reduce the number of parts and reduce the manufacturing cost.

It is a figure which shows the external gear pump of Example 1 which concerns on this invention, Comprising: It is sectional drawing along the C-C 'line in FIG. It is a figure which shows the external gear pump of Example 1 which concerns on this invention, Comprising: It is sectional drawing along the A-A 'line | wire in FIG. It is a figure which shows the external gear pump of Example 1 which concerns on this invention, Comprising: It is sectional drawing along the B-B 'line | wire in FIG. It is a top view of the 1st seal block which constitutes the external gear pump of Example 1 concerning the present invention. It is a top view which shows the lower surface of the intermediate casing which comprises the external gear pump of Example 1 which concerns on this invention. In the external gear pump of Example 1 which concerns on this invention, it is a top view at the time of attaching a 1st seal block using the jig | tool 60. FIG. FIG. 7 is a front view when the first seal block is attached using a jig 60 in the external gear pump according to the first embodiment of the present invention, and is a cross-sectional view taken along line EE ′ in FIG. 6. It is a perspective view of the convex insertion pin used for the external gear pump concerning the present invention. It is a top view of the state which removed the intermediate casing 6 from the external gear pump of Example 2 which concerns on this invention. FIG. 12 is a cross-sectional view taken along line H-H ′ of FIG. 11 in the external gear pump according to the third embodiment of the present invention. FIG. 11 is a cross-sectional view taken along line GG ′ of FIG. 10 in the external gear pump according to the third embodiment of the present invention. It is sectional drawing along the FF 'line of FIG. 10 about the external gear pump of Example 3 which concerns on this invention. It is sectional drawing which shows the structure of the external gear pump of Example 4 which concerns on this invention.

  Embodiments will be described below with reference to the drawings.

[Example 1]
Example 1 of the external gear pump according to the present invention will be described. Embodiment 1 is an external gear pump 1 shown in FIGS. 1 to 3, and includes a front casing 2 on the side where a drive source such as a motor (not shown) is installed, a rear casing 3 on the opposite side of the motor, An intermediate casing 6 provided between the front casing 2 and the rear casing 3, a drive shaft 4, a driven shaft 5 driven by a drive source, a driven shaft 5, and an intermediate casing 6 that are freely rotated with respect to these casings. The external gear pump includes a first pump portion 20 provided on the front casing 2 side and a second pump portion 10 provided on the rear casing 3 side.

  The front casing 2 has a stepped shape into which the seal member 36 can be inserted on the drive source side and the front bearing 30 of the drive shaft can be inserted on the intermediate casing side 6, and a through hole 2a into which the drive shaft 4 can be inserted. A stepped insertion hole 2b is provided so that the driven shaft 5 and the front shaft bearing 32 of the driven shaft can be inserted.

  The rear casing 3 has a stepped shape so that the rear bearing 31 of the drive shaft 4 can be inserted on the intermediate casing 6 side, the insertion hole 3a into which the drive shaft 4 can be inserted, and the rear of the driven shaft 5 and the driven shaft. A stepped insertion hole 3b is provided so that the side bearing 33 can be inserted.

  The intermediate casing 6 is provided with a cylindrical recess 6c on the front casing 2 side and a cylindrical recess 6d on the rear casing 3 side so that the first pump part 20 and the second pump part 10 are inserted. On the other hand, an insertion hole 6f for inserting the seal member 35 is provided, and a through hole 6a for inserting the drive shaft 4 and a through hole 6b for inserting the driven shaft 5 are provided.

  The drive shaft 4 is connected to the rear casing 3 via a rear bearing 31 of the drive shaft provided in the rear casing 3 and to the front casing 2 via a front bearing 30 of the drive shaft provided on the front casing 2 side. It is pivotally supported.

  The driven shaft 5 is connected to the rear casing 3 via the rear bearing 33 of the driven shaft provided in the rear casing 3 and to the front casing 2 via the front bearing 32 of the driven shaft provided on the front casing 2 side. It is pivotally supported.

  The first pump part 20 is inserted into the cylindrical recess 6c, and the second pump part 10 is inserted into the cylindrical recess 6d, respectively, where the pump functions. The first pump part 20 and the second pump part 10 have the same configuration and operation except that the first pump part 20 is attached to the front casing 2 and the second pump part 10 is attached to the rear casing 3. Since there is no fundamental difference, the configuration and operation of these pump units will be described in detail below using the first pump unit 20 as an example.

  The first pump unit 20 includes a first drive gear 23, a first driven gear 24, a first seal block 22, a first side plate 21, a first seal block seal member 26, and a first side plate seal member 25. The first drive gear 23 meshes with the first driven gear 24, and both the gears 23, 24 rotate as a unit. Further, the first drive gear 23 is provided with a key groove, and the drive pin 4a that is fitted into the drive shaft 4 and operates integrally is fitted into the key groove, whereby the first drive gear 23 and the drive shaft 4 are fitted. Rotate together. Similarly, the first driven gear 24 is similarly provided with a key groove, and a drive pin 5a that operates integrally with the driven shaft 5 is fitted into the key groove. The first driven gear 24 and the driven shaft 5 Rotate together. Accordingly, as the drive shaft 4 rotates, the first drive gear 23, the first driven gear 24, and the driven shaft 5 rotate together.

  The first side plate 21 is a member that makes sliding contact with the side surfaces of the first drive gear 23 and the first driven gear 24 and seals the side surfaces of the gear, and is sandwiched between the intermediate casing 6 and both the gears 23 and 24. Has been. A seal member 25 is provided on the first casing 21 on the side plate 21 side. The first seal block 22 has an L shape as shown in FIG. 1 and seals the tooth tip at the same time as sealing the surface of the gear side opposite to the first side plate 21.

  Next, the structure of the first seal block 22 will be described with reference to FIG. The first seal block 22 is provided with a groove 22d so as to form a sliding surface on the inner side of the tooth bottom, and has a structure in which the side surface of the gear is in sliding contact with a convex sliding contact portion 22g. For example, resin can be used for the first seal block 22 to reduce sliding friction. In addition, in order to position the first seal block 22 in the front casing 2, the first seal block first pin insertion hole 22a is on the right side and the first seal block second pin insertion hole 22b is on the left side in FIGS. Provided. Further, as shown in FIG. 4, the first seal block 22 has tooth tip sliding surfaces 22e and 22f that seal when the tooth tip slides.

  A method for attaching the first seal block 22 will be described. Since the first seal block tooth sliding surfaces 22e and 22f seal with the gear teeth, the first seal block teeth sliding surfaces 22e and 22f have a diameter slightly smaller than the diameter of the tooth tip passage when the pump is driven. It is required that there is little individual variation in the hit amount. If this is not appropriate, an increase in leakage at the tooth tip due to the formation of a gap when pressure is applied, and variation in the volumetric efficiency due to variations in the amount of contact of the tooth tip with the first seal block 22 described later, etc. There is a risk of connection.

  Therefore, a seal block positioning method will be described with reference to FIGS. First, a jig 60 composed of a shaft portion 60a having the maximum diameter that can be inserted into the through hole 2a of the front casing 2 and a gear replacement portion 60b having a diameter corresponding to a desired tooth tip position is used. Here, the diameter corresponding to the desired tooth tip position is, for example, when the tooth tip is closest to the tooth tip seal side, [Distance from bearing center to tooth tip]> [Distance from bearing center to tooth tip seal] When the tooth tip is farthest from the tooth tip seal, the [distance from the bearing center to the tooth root on the tooth tip seal side] <[distance from the bearing center to the tooth tip seal] relationship It means a diameter in a range where is established.

  Next, the fixing position of the first seal block 22 is determined by inserting the jig 60 having such a configuration into the front casing 2. In this state, the hole penetrating from the first seal block 22 to the front casing 2 is located on the right side of the line connecting the drive shaft to the driven shaft (from the first pin insertion hole 22a of the first seal block 22 on the suction side, Drill, for example, on the left side (hole to the first pin insertion hole 2d) and the left side (discharge side, hole from the second pin insertion hole 22b of the first seal block 22 to the second pin insertion hole 2c of the front casing 2). Use it for co-drilling. Thereafter, the first pin 50 is inserted into the first pin insertion hole 22 a of the first seal block 22 and the first pin insertion hole 2 d of the front casing 2, the second pin insertion hole 22 b of the first seal block 2, and the first pin 2 of the front casing 2. The second pin 51 is inserted into the 2-pin insertion hole 2c. Thus, the first seal block 22 is fixed to the front casing 2. The second seal block 12 is fixed to the rear casing 3 by the same method.

  The first pin 50 is formed in a columnar shape, and the first pin insertion hole 22a of the first seal block 22 and the first pin insertion hole 2d of the front casing 2 are formed in a cylindrical shape having the same diameter as the first pin 50. . The first seal block 22 is rotatably fixed to the front casing 2 by the first pin 50. The second pin 51 is similarly formed in a columnar shape, and the second pin insertion hole 22b of the first seal block 22 and the second pin insertion hole 2c of the front casing 2 are formed in a cylindrical shape having the same diameter as the second pin 51. Is done. Thus, the first seal block 22 that is freely rotatable by the first pin 50 is restricted from moving in the rotational direction, and is restricted from moving in a plane perpendicular to the drive shaft 4 and the driven shaft 5 with respect to the front casing 2. .

  The second pin 51 only needs to be able to regulate the movement in the rotational direction around the first pin 50. Instead of the columnar shape, the second pin 51 may have, for example, a convex shape as shown in FIG. It is preferable to install in an orientation that restricts movement in the vertical direction (the rotational direction about the first pin 50). Thus, the position of the first seal block 22 with respect to the front casing 2 is fixed.

  Further, as shown in FIG. 1, a first seal block seal member 26 is provided in an annular shape on the outer peripheral portion of the side surface of the first seal block 22 on the front casing 2 side. Inside the first seal block seal member 26, the suction pressure is low. On the other hand, the high pressure discharge pressure generated when the pump is driven in the outer side of the side seal portion 22g on the side surface on the gear side of the first seal block 22 and in the outer side of the seal line 22h on the side surface of the intermediate casing 6. It takes. Therefore, the force by this discharge pressure generates a force that pushes the first seal block 22 onto the front casing 2 from the upper side to the lower side in FIG. 1 (from the front side to the back side in FIG. 2), The movement of the first seal block 22 in the vertical direction in FIG. 1 is limited. At this time, it is sufficient if the movement in the vertical direction can be restricted, and the first seal block seal member 26 may be installed inside instead of the outer peripheral portion of the first seal block 22. However, the condition is that the pressure receiving area outside the sealing member 26 provided on the inner side is smaller than the high pressure receiving area on the opposite side.

  In this case, although the processing is performed by the common hole, it is sufficient that the distance from the bearing center to the tooth tip is a desired distance. Therefore, the first pin insertion hole 22a of the first seal block 22 for that purpose, the first of the front casing. It is only necessary that the position and shape of the pin insertion hole 2d, the second pin insertion hole 22b of the first seal block 22, and the second pin insertion hole 2c of the front casing 2 can be accurately processed, and the processing method is not limited to this.

  As a result, the first seal block 22 is fixed to the drive shaft 4 and the driven shaft 5 both in the orthogonal direction and in the parallel direction.

  Next, the operation and effect of the first embodiment will be described. When the drive shaft 4 is driven by a drive source (not shown), the first drive gear 23 also rotates in the direction of the arrow 55 in FIG. 2, and the first driven gear 24 meshed with the first drive gear 23 is moved to the arrow 55. Rotate in the direction of '.

  At this time, the liquid enters the intermediate casing 6 from the suction port 41 through a path (not shown), fills the suction portion 56, and is accommodated in the tooth gap as the first drive gear 23 and the first driven gear 24 rotate. And conveyed in the rotation direction. Thereafter, the first driving gear 23 and the first driven gear 24 start to mesh with each other on the discharge portion 57 side, so that the liquid is pushed out from the tooth gap. Therefore, when the liquid is continuously conveyed by the rotation of the first drive gear 23 and the first driven gear 24, the pressure on the discharge part 57 side is increased, and the liquid is discharged from a discharge port (not shown). At this time, since the respective tooth tips of the first drive gear 23 and the first driven gear 24 and the seal block 22 are sealed, only the suction portion 56 side of the seal becomes low pressure, and other portions become high pressure. Become.

  During driving of the pump, the first drive gear 23 and the first driven gear 24 are located between the clearance between the drive shaft 4 and the driven shaft 5 and between the drive shaft 4 and the driven shaft 5 and the bearings. The tooth tip is pushed rightward from the high pressure side to the low pressure side, that is, in FIG. When assembled so as to come into contact with the tooth tip sliding surfaces 22e and 22f of the first seal block 22 when pushed, the tooth tip sliding surfaces 22e and 22f of the first seal block 22 are cut by the amount of movement of the tooth tips. Is done. In the external gear pump 1, contact is made by this cutting to absorb manufacturing variations between the tooth tip sliding surfaces 22e and 22f and the first drive gear 23 or the first driven gear 24, and the tooth tip and the first tip when the pump is driven. Minimizing the gap with the one seal block 22 has the effect of increasing volumetric efficiency by minimizing the return of liquid from the high pressure side to the low pressure side.

  According to the external gear pump 1 of the first embodiment, the position of the first seal block 22 with respect to the gear can be determined with high accuracy, so that differences in the dimensions of parts due to manufacturing variations can be absorbed during assembly. Further, the contact time can be adjusted by adjusting the fixing position of the first seal block 22. For example, when the jig 60 is used, the diameter is adjusted, and the first seal block 22 is applied to the jig 60 for positioning, fixing, and fixing at an intermediate position is easy. As a result, it is possible to obtain a configuration capable of obtaining a high volumetric efficiency with a minimum hitting time.

  Further, since the first seal block 22 is formed integrally with the gear side surface sliding portion and the tooth tip sliding portion, it is possible to select a material having a small sliding resistance at the sliding portion. In addition, since the load is supported by the first pin 50, the material of the first seal block 22 can be selected with emphasis on slidability. Thereby, it can be set as a gear pump with sufficient mechanical efficiency.

  Furthermore, since the first seal block 22 is fixed at two locations, it is possible to increase the bending rigidity by using a pin having a large cross-sectional area. Therefore, the deformation of the first seal block 22 with respect to the load is small, the gaps at the tooth tip sliding surfaces 22e and 22f can be reduced, and the high sealing performance of the external gear pump 1 can be realized.

  In addition, since two pump parts are provided, for example, when used in a pump used for braking, a highly reliable external gear pump capable of producing two separated high pressures with one drive source is provided. You can also.

[Example 2]
The circumscribed gear pump of the second embodiment is an example in which the first pin insertion hole 22a of the first seal block 22 is not circular but has a shape in which only one direction is restricted.

  FIG. 9 is a plan view (a diagram corresponding to FIG. 5 of the first embodiment) with the intermediate casing 6 removed from the external gear pump of the second embodiment. As shown in FIG. 9, the first pin insertion hole 22a of the first seal block 22 is machined into a shape in which the right half of FIG. 9 has the same diameter as the first pin 50 and a gap is provided on the left side. Is done.

  The second pin insertion hole 22b of the first seal block 22 may be cylindrical, and the second pin 51 may be columnar or convex as shown in FIG.

  When the pump is driven, high pressure is applied to the first seal block 22 from the right side in FIG. 9, and from the left side, only the portion where the gear tooth sliding part is sealed is low, and a leftward force is applied as a whole. ing. Therefore, since the first seal block 22 does not move to the right side, the first seal block 22 is rotatably fixed to the front casing 2 in the same manner as when the entire circumference is restricted by the restriction of only a half circumference. The Further, the first seal block 22 is also restricted from moving in the rotational direction of the first seal block 22 by the second pin 51, and the first seal block 22 is connected to the drive shaft 4 and the driven shaft 5 with respect to the front casing 2. On the other hand, the movement in the plane orthogonal to each other is restricted. Other configurations and operations are the same as those in the first embodiment.

  In the second embodiment, in addition to the same effects as those of the first embodiment, the assembly is facilitated by the restraint of only a half circumference, and there is an effect that the component accuracy of each part can be relaxed.

[Example 3]
The external gear pump of Example 3 is an example provided with one pump part.
The configuration of the external gear pump 1 according to the third embodiment will be described with reference to FIGS. In the third embodiment, the front casing 2 provided on the side where a drive source such as a motor (not shown) is installed, the lid casing 70 provided on the opposite side of the motor, and the front casing 2 and the lid casing 70 are rotated. A pair of freely installed shafts 4 and 5, which are composed of a drive shaft 4 driven by a drive source, its driven shaft 5, a pump portion 90 provided on the front casing 2 side in the lid casing 70, etc. Is done.

  The lid casing 70 is provided with a cylindrical recess 70a into which the pump unit 90 is inserted. The pump unit 90 has the same configuration as the first pump unit 20 in the first embodiment, and the mounting method is the same as that in the first or second embodiment. Other configurations and operations are the same as those in the first embodiment.

  According to the third embodiment, the same effect as that of the first or second embodiment can be obtained. Furthermore, in Example 3, since there is only one pump part, it is suitable as a pump used for hydraulic equipment with only one system for boosting, and the external gear pump can be combined in a simple configuration.

[Example 4]
The external gear pump of the fourth embodiment is an example in which one pump portion is provided and one rotary shaft is pivotally supported at two locations.

With reference to FIG. 13, the structure of the external gear pump 1 of Example 4 is demonstrated.
The lid casing 70 is provided with a cylindrical recess 70a on the front casing 2 side so that the pump part 90 can be inserted. The lid casing 70 is provided with a stepped insertion hole 70b, and the drive shaft 4 and the bearing 80 (on the lid casing side) are inserted. Further, the lid casing 70 is further provided with an insertion hole 70c having a stepped shape, and the driven shaft 5 and the bearing 81 (on the lid casing side) are inserted.

  The drive shaft 4 is pivotally supported on the front casing 2 via a bearing 30 on the front casing side, and is pivotally supported on the lid casing 70 via a bearing 80 on the lid casing side. The driven shaft 5 is pivotally supported on the front casing 2 via a bearing 32 on the front side of the driven shaft, and is pivotally supported on the lid casing 70 via a bearing 81 on the lid casing side. Other configurations and operations are the same as those of the third embodiment, and the same effects as those of the third embodiment can be obtained.

  In the fourth embodiment, since both the drive shaft 4 and the driven shaft 5 are both supported, the load is dispersed and the inclination of the shaft can be suppressed. As a result, sliding on the gear sliding surface and the tooth tip sliding surface can be achieved. Since the increase in resistance can be suppressed, the external gear pump 1 capable of improving the slidability can be provided.

  In the first to fourth embodiments described above, the pin is used, but instead of this, a movement restricting means such as a key or a bolt may be used. Moreover, as a material of the seal block, various metals, synthetic resins, and the like are used.

1 External gear pump
2 Front casing
3 Rear casing
4 Drive shaft
5 Driven shaft
6 Intermediate casing
7 Side plate
10 Second pump section
12 Second seal block
13 Second drive gear
14 Second driven gear
20 1st pump part
22 First seal block
23 First drive gear
24 1st driven gear
50 Pin 1
51 Pin 2

Claims (7)

A casing,
A pair of rotating shafts supported by bearings provided in the casing;
At least a pair of gears fixed to the pair of rotating shafts and circumscribed and meshed with each other;
A side plate provided in sliding contact with one side surface of the pair of gears;
A seal block integrally formed with a side sliding portion that is in sliding contact with the other side surface of the pair of gears and a tooth tip sliding portion that seals the tooth tip of the gear;
Movement restriction means is provided on both sides of a straight line connecting the shafts of the pair of gears, and the seal block is restricted from moving relative to the casing in a plane perpendicular to the rotation axis. Circumscribed gear pump. At least one of the movement limiting means restricts the seal block from moving in a direction substantially parallel to a straight line connecting the pair of gears within a plane orthogonal to the rotation axis;
At least the other one of the movement restricting means includes the seal block in a direction substantially orthogonal to or substantially parallel to a straight line connecting the pair of gears in a plane orthogonal to the rotation axis. The external gear pump according to claim 1, wherein movement of the external gear is restricted. At least one of the movement limiting means restricts the seal block from moving in a direction substantially parallel to a straight line connecting the pair of gears in a plane perpendicular to the rotation axis;
At least the other one of the movement limiting means is a direction substantially orthogonal to a straight line connecting the pair of gears in a plane orthogonal to the rotation axis, and the pair of the pair of gears from the tip sliding portion. The external gear pump according to claim 1, wherein the seal block is restricted from moving in a gear direction.   The external gear pump according to any one of claims 1 to 3, wherein at least one of the movement limiting means is a pin.   The external gear pump according to any one of claims 1 to 4, wherein the seal block is made of resin. A seal member is provided on a surface of the seal block in contact with the casing;
The area of the portion that is in contact with the casing and that receives the external high pressure surrounded by the seal member is smaller than the area that receives high pressure on the opposite side of the seal block. The external gear pump according to claim 5.   The external gear pump according to claim 6, wherein the seal member is provided in a circular shape on a surface that contacts the casing of the seal block.

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