JP2016070209A - Gear pump or motor - Google Patents

Abstract

A working fluid leaks from a space surrounded by a tooth surface of a gear and an inner peripheral surface of a spectacle hole of a casing to a low-pressure suction passage side, and there is a possibility that the efficiency of the gear pump or the motor is lowered. A suction-side communication passage 31 communicating with a low-pressure space in a spectacle hole has a suction passage 32 (first flow passage) and a diffusion passage 33 (first flow passage) having a larger flow path than the suction passage 32 (first flow passage). 2 flow paths). An opening 34 extending along the axial direction of the helical gear is formed at the boundary between the low-pressure space of the spectacle hole 10 and the diffusion passage 33 (second flow path). When the opening 34 is viewed from the eyeglass hole 10 to the suction passage 32 (first flow path) side, the opening width W2 on the side where the teeth of the pair of helical gears are far away is the width of the pair of helical gears. It is wider than the opening width W1 on the side where the tooth trace approaches. [Selection] Figure 4

Description

  The present invention relates to a gear pump or a motor using a helical gear.

  As a conventional gear pump, a casing having a spectacle hole having a cross-sectional shape of approximately 8 characters, a drive gear and a driven gear housed in a spectacle hole of the casing and configured as a helical gear, and the outside of the casing There is known one having a suction passage for sucking the working fluid from the inside and a discharge passage for discharging the working fluid pressurized by the glasses hole to the outside of the casing. In this gear pump, the working fluid taken into the space surrounded by the tooth surface of the gear and the inner peripheral surface of the eyeglass hole is transferred to the discharge passage side by the rotation of the gear, and is discharged to the outside of the casing.

Utility model registration No. 3189138

  Hereinafter, an example of the gear pump as described above will be described with reference to FIGS. 9 and 10 are for explaining the diffusion passage 133 formed between the spectacle hole 110 and the suction passage 132 of the casing 106 and the opening 134 formed at the boundary between the spectacle hole 110 and the diffusion passage 133. FIG. FIG. 11 is a view for explaining a seal region where the gear tooth tip and the inner peripheral surface 110a of the eyeglass hole 110 abut. In FIG. 10, members such as the drive gear 102 and the driven gear 103 accommodated in the casing 106 are omitted, and only the casing 106 is illustrated. 10 and 11, a range b in the figure indicates a width at which the gear tip contacts the inner peripheral surface of the eyeglass hole.

  In the gear pump as described above, as shown in FIG. 9, it extends along the axial direction of the drive gear 102 and the driven gear 103 between the spectacle hole 110 of the casing 106 and the suction passage 132, and the suction passage 132. A diffusion passage 133 having a larger flow path is formed, and an opening 134 extending along the axial direction of the drive gear 102 and the driven gear 103 is formed at the boundary between the spectacle hole 110 and the diffusion passage 133. Can be considered. Due to the diffusion passage 133 and the opening 134, the working fluid sucked into the suction passage 132 is diffused in the diffusion passage 133 and then flows into the eyeglass hole 110, so that the working fluid easily spreads over the entire tooth width of the gear. . As shown in FIG. 10, it is conceivable that the opening width of the opening 134 is constant in the axial direction of the gear so that processing is easy. In addition, it is conceivable that the opening 134 is formed such that both end portions 135 and 136 in the width direction are in contact with the outer peripheral surface of the suction passage 132 so that the suction passage 132 is not blocked.

  By the way, the working fluid flowing into the eyeglass hole 110 from the suction passage 132 is taken into a space surrounded by the tooth surface of the gear and the inner peripheral surface 110a of the eyeglass hole 110 and is sent to the high-pressure discharge passage 142 side. At this time, in order to prevent the working fluid taken into the space from leaking to the low-pressure suction passage 132 side, the gear tooth tip and the inner peripheral surface 110a of the eyeglass hole 110 are in contact with each other (a very narrow gap is opened). Must be close). As shown in FIG. 9, when the gear pump is discharging high-pressure working fluid, the drive gear 102 and the driven gear 103 are pressed toward the suction passage 132 by the high pressure in the high-pressure space 124 on the discharge passage 142 side. Therefore, the drive gear 102 and the driven gear 103 are close to the suction passage 132 side. Therefore, of the plurality of tooth tips of the gear, the tooth tip that is in contact with the inner peripheral surface 110a of the spectacle hole 110 is the tooth tip located on the suction passage 132 side, and the working fluid is moved to the suction passage 132 side by this tooth tip. Leakage is prevented.

  In this gear pump, helical gears are used for the drive gear 102 and the driven gear 103. The teeth of the drive gear 102 and the driven gear 103 have the same twist angle, but the twist direction is opposite. Therefore, when viewed from the side, there are a closer side and a farther side of the two gear teeth. The amount of twist of the drive gear 102 and the driven gear 103 is, for example, one front pitch (in other words, the overlap meshing rate is 1).

  As described above, in a gear in which the tooth trace is twisted by one front pitch, at least one full width of the tooth tip is in contact with the inner peripheral surface 110a of the spectacle hole 110 at any moment. At least a seal area corresponding to two front pitches is required on the surface 110a. For example, as shown in FIG. 11A, when the tooth tip 151 of the drive gear 102 is closest to the opening 134 as far as it can be sealed, the seal area necessary for the inner peripheral surface 110a of the eyeglass hole 110 is 1 It becomes the front pitch. However, as shown in FIG. 11 (b), when a part of the tooth tip 151 is in a portion facing the opening 134, it is taken into the space surrounded by the tooth surface of the gear and the inner peripheral surface 110 a of the eyeglass hole 110. The leaked working fluid leaks from the hatched portion in FIG. 11B, so that the working fluid is prevented from leaking at the tooth tip 152 of the tooth adjacent to the tooth having the tooth tip 151. For this reason, a seal area of about 2 front pitches is required. Therefore, in a gear in which the tooth traces are twisted by one front pitch, as shown in FIG. 11C, a seal region corresponding to at least two front pitches from the opening 134 is required on the inner peripheral surface 110a of the eyeglass hole 110. . In contrast, in a gear pump using a spur gear, at least a seal region for one pitch is sufficient.

  In the gear pump as described above, the two front pitches become the seal region, but the tooth tip is difficult to be pressed against the inner peripheral surface 110a of the spectacle hole 110 in the portion of the seal region away from the opening 134. The working fluid taken in the space surrounded by the tooth surface and the inner peripheral surface 110a of the eyeglass hole 110 is likely to leak to the suction passage 132 side. Therefore, in order to prevent the working fluid from leaking from the space to the suction passage 132 side, the opening width of the opening 134 is made as narrow as possible, and the seal region is viewed from the eyeglass hole side, and the suction passage 132 side (the suction passage It is desirable to bring it close to the shaft center side.

  On the other hand, if the opening width of the opening 134 is narrowed, the flow rate of the working fluid at the time of passage becomes high and cavitation is likely to occur, so that there is a problem that the maximum rotational speed of the gear pump cannot be increased. Therefore, in order to ensure the maximum rotational speed of the gear pump at a predetermined level or more, it is necessary to widen the opening width of the opening 134 and ensure the area of the opening 134 at a predetermined area or more. Therefore, in the gear pump as described above, the opening width of the opening 134 can be determined in consideration of the balance between bringing the seal region as close to the suction passage 132 as possible and securing the area of the opening 134 to a predetermined area or more. Desired. As a result, the seal region cannot be sufficiently moved to the suction passage 132 side, and the working fluid leaks to the suction passage 132 side from the space surrounded by the gear tooth surface and the inner peripheral surface 110a of the eyeglass hole 110, The efficiency of the gear pump may be reduced.

  Moreover, as a conventional gear motor, there exists what was comprised similarly to the conventional gear pump. Also in this gear motor, the opening width of the opening 134 is made as small as possible in order to prevent the working fluid from leaking from the space surrounded by the gear tooth surface and the inner peripheral surface 110a of the eyeglass hole 110 to the suction passage 132 side. Thus, it is desirable to bring the seal area as close to the suction passage 132 as possible. However, on the other hand, if the opening width of the opening 134 is narrowed, there is a problem that the flow resistance of the diffusion passage 133 increases and the efficiency of the gear motor decreases. It is necessary to secure an area of a predetermined area or more. Therefore, even in the gear motor, it is required to determine the opening width of the opening 134 in consideration of the balance between bringing the seal region as close to the suction passage 132 as possible and securing the area of the opening 134 to a predetermined area or more. As a result, the seal region cannot be sufficiently moved to the suction passage 132 side, and the working fluid leaks to the suction passage 132 side from the space surrounded by the gear tooth surface and the inner peripheral surface 110a of the eyeglass hole 110, The efficiency of the gear motor may be reduced.

  Then, the objective of this invention is providing the gear pump or motor which can prevent that the efficiency of a gear pump or a motor falls.

  If the opening width of the opening formed at the boundary between the diffusion passage and the spectacle hole is constant in the axial direction of the gear as in the gear pump described above, the gear teeth are inclined with respect to the gear axis. Therefore, even if the gear teeth are on the most open side within the sealable range, the pair of helical gears is always used for sealing on the inner peripheral surface of the eyeglass hole on the far side. There is a region that cannot be used (for example, in the above gear pump, the shaded portion in FIG. 11A). The inventors of the present invention have studied to utilize an area not used for the seal, and have completed the present invention.

  A gear pump or motor according to a first aspect of the present invention includes a casing having a spectacle hole, and is accommodated in the spectacle hole, and abuts on the inner peripheral surface of the spectacle hole so that the spectacle hole is a high-pressure space and a low-pressure space. A pair of helical gears and a communication passage communicating with the low pressure space of the spectacle hole, the communication passage including a first flow path that opens to the outside of the casing, and a low pressure space of the spectacle hole. And a second channel that extends along the axial direction of the helical gear and is larger than the first channel. An opening extending along the axial direction of the helical gear is formed at the boundary between the low pressure space and the second flow path, and the opening extends from the eyeglass hole to the first flow path side. When viewed, the opening width on the far side of the pair of helical gears , And wherein the wider than the opening width of the side where the tooth trace approach of helical gears of said pair.

  In this gear pump or motor, a pair of helical gears has a wider opening width on the side farther away than an opening width on the side closer to the helical gear teeth of a pair of helical gears. By utilizing the region where the tooth traces of the gear are not used for the seal on the far side, the first flow path (suction passage) is seen from the eyeglass hole side as much as possible to the seal region where the pair of helical gear teeth approaches. ) And the area of the opening was increased. As a result, for example, when used as a gear pump, the working fluid is prevented from leaking to the first flow path (suction passage) side from the space surrounded by the tooth surface of the helical gear and the inner peripheral surface of the eyeglass hole. However, cavitation can be prevented from occurring. In addition, when used as a gear motor, the working fluid is prevented from leaking to the first flow path (suction passage) side from the space surrounded by the tooth surface of the helical gear and the inner peripheral surface of the eyeglass hole. And it can prevent that the pressure loss in a 2nd flow path (diffusion passage) increases. Therefore, it can prevent that the efficiency of a gear pump or a motor falls.

  A gear pump or motor according to a second aspect of the present invention is the gear pump or motor according to the first aspect of the present invention, wherein the opening width on the side where the teeth of the pair of helical gears approach is larger than the width of the first flow path. Is also narrow.

  In this gear pump or motor, the opening width of the pair of helical gears on the side where the tooth traces approach is narrower than the width of the first flow path (suction passage). Can be brought closer to the first flow path (suction passage) side.

  A gear pump or motor according to a third aspect of the invention is the gear pump or motor according to the first or second aspect of the invention, wherein the opening is a tooth line (tooth tip twist angle) in the tooth tip cylinder of the helical gear. The opening width changes along the line.

  In this gear pump or motor, since the opening width of the opening changes so as to follow the tooth trace in the tooth tip cylinder of the helical gear, the area of the opening can be efficiently increased.

  A gear motor or pump according to a fourth aspect of the invention is the gear pump or motor according to the third aspect of the invention, wherein the end in the width direction of the opening is inclined so as to follow the tooth trace in the tooth tip cylinder of the helical gear. It is characterized by that.

  In this gear pump or motor, since the end in the width direction of the opening is inclined so as to follow the tooth trace in the tooth tip cylinder of the helical gear, the area of the opening can be increased more efficiently.

  A gear motor or pump according to a fifth aspect of the present invention is the gear pump or motor according to any one of the first to fourth aspects of the invention, wherein the second flow path is on the side where the teeth of the pair of helical gears are far away. The depth from the opening is deeper than the depth from the opening on the side closer to the teeth of the pair of helical gears.

  In this gear pump or motor, the flow volume of the second flow path (diffusion path) can be increased on the side where the teeth of the pair of helical gears having a large opening width are far away, so that the pressure loss of the working fluid can be reduced. .

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, the pair of helical gears has a pair of helical gears whose opening width on the far side is larger than the opening width on the side where the pair of helical gears approaches. By utilizing the region where the tooth traces of the pair of helical gears are not used for the seal on the far side, the seal region on the side where the tooth traces of the pair of helical gears approach is moved as close to the first flow path (suction passage) as possible, and The area of the opening was increased. As a result, for example, when used as a gear pump, the working fluid is prevented from leaking to the first flow path (suction passage) side from the space surrounded by the tooth surface of the helical gear and the inner peripheral surface of the eyeglass hole. However, cavitation can be prevented from occurring. In addition, when used as a gear motor, the working fluid is prevented from leaking to the first flow path (suction passage) side from the space surrounded by the tooth surface of the helical gear and the inner peripheral surface of the eyeglass hole. And it can prevent that the pressure loss in a 2nd flow path (diffusion passage) increases. Therefore, it can prevent that the efficiency of a gear pump or a motor falls.

  In the second invention, since the opening width on the side where the teeth of the pair of helical gears approach is narrower than the width of the first flow path (suction passage), the tooth tip of the gear and the inner peripheral surface of the eyeglass hole It is possible to bring the seal area where the abuts closer to the first flow path (suction passage) side.

  In the third aspect of the invention, the opening width of the opening changes so as to follow the tooth trace in the tooth tip cylinder of the helical gear, so that the area of the opening can be efficiently increased.

  In the fourth aspect of the invention, since the end in the width direction of the opening is inclined so as to follow the tooth trace in the tooth tip cylinder of the helical gear, the area of the opening can be increased more efficiently.

  In the fifth aspect of the invention, the flow volume of the second flow path (diffusion passage) can be increased on the side where the teeth of the pair of helical gears having a large opening width are distant from each other, so that the pressure loss of the working fluid can be reduced.

It is a figure explaining the whole gear pump composition concerning a 1st embodiment of the present invention. It is a figure explaining the structure of a drive gear and a driven gear. It is sectional drawing (horizontal sectional drawing of a gear pump) in the III-III line | wire shown in FIG. It is sectional drawing in the IV-IV line shown in FIG. FIG. 5 is a partially enlarged view of FIG. 4. (A) shows the opening of the gear pump according to the embodiment of the present invention, (b) shows the opening of the gear pump according to the first comparative example, and (c) shows the second comparative example. The opening of a gear pump is shown. It is sectional drawing in the VII-VII line shown in FIG. FIG. 6 is a view corresponding to FIG. 5 of a gear pump according to a second embodiment of the present invention. It is a horizontal sectional view of the gear pump concerning a comparative example. FIG. 10 is a sectional view taken along line XX shown in FIG. 9. It is a figure for demonstrating a seal | sticker area | region.

  Hereinafter, embodiments of a gear pump according to the present invention will be described with reference to the drawings.

[First Embodiment]
[Overall configuration of gear pump]
First, with reference to FIGS. 1-4, the whole structure of the gear pump which concerns on 1st Embodiment is demonstrated. Here, FIG. 1 is a diagram illustrating the overall configuration of the gear pump 1 of the present embodiment. FIG. 2 is a diagram illustrating the configuration of the drive gear 2 and the driven gear 3 that are configured as helical gears. 3 and 4 are views for explaining the shape of the opening 34 formed between the eyeglass hole 10 of the main body 7 (casing 6) and the diffusion passage 33 (second flow path). In FIG. 4, members such as the drive gear 2 and the driven gear 3 housed in the main body 7 (casing 6) are omitted, and only the main body 7 (casing 6) is illustrated. Moreover, in FIG. 4, the range b in the figure shows the width | variety with which the tooth | gear tip of a gear contact | abuts with a spectacles hole inner peripheral surface.

  As shown in FIG. 1, the gear pump 1 of this embodiment includes a pair of drive gears 2 and driven gears 3 that mesh with each other, and drive shafts 4a and 4b and a driven shaft 5a that support the drive gears 2 and 3 respectively. 5b and a casing 6 that houses the drive gear 2, the driven gear 3, the drive shafts 4a and 4b, and the driven shafts 5a and 5b. The gear pump 1 of the present embodiment, for example, sucks and pressurizes the working fluid supplied from a tank that stores the working fluid (for example, working oil), and then discharges the working fluid to a hydraulic device (for example, a hydraulic device). To supply.

  The casing 6 has a main body 7 having an internal space (glasses hole 10) having a substantially cross-sectional shape of 8, a mounting 8 screwed to one end surface of the main body 7, and is screwed to the other end surface of the main body 7. Cover 9. In the gear pump 1, the spectacle hole 10 formed inside the main body 7 is closed by the mounting 8 and the cover 9.

  As shown in FIGS. 1 to 3, the drive gear 2 and the driven gear 3 are each configured as a helical gear and are accommodated in a spectacle hole 10 formed inside the casing 6. In the eyeglass hole 10, the drive shafts 4 a and 4 b extend from both end surfaces of the drive gear 2 along the axial direction, and the driven shafts 5 a and 5 b extend from both end surfaces of the driven gear 3 along the axial direction. The The drive shaft 4a is inserted through an insertion hole 8a formed in the mounting 8, and a drive means (not shown) is connected to the end of the drive shaft 4a. In the gear pump 1, the driving gear 2 and the driven gear 3 are accommodated in the eyeglass hole 10 in a state of being engaged with each other, and their tooth tips abut against the inner peripheral surface 10 a of the eyeglass hole 10 (a very narrow gap is opened). (Including cases where they are close to each other). As a result, the eyeglass hole 10 has a meshing portion between the driving gear 2 and the driven gear 3, a contact portion between the tooth tip of the driving gear 2 and the inner peripheral surface 10 a of the eyeglass hole 10, and the tooth tip of the driven gear 3 and the eyeglass hole 10. The high-pressure space 24 and the low-pressure space 25 are divided into two parts with a contact portion with the inner peripheral surface 10a as a boundary.

  The driving gear 2 is rotated in the direction of arrow R in FIG. 3 by driving means (not shown). On the other hand, the driven gear 3 meshed with the drive gear 2 rotates in the direction opposite to the rotation direction of the drive gear 2 by the rotation of the drive gear 2, that is, in the direction of the arrow R 'in FIG. The teeth of the drive gear 2 and the driven gear 3 are inclined with respect to the axes of the drive gear 2 and the driven gear 3, respectively. The tooth traces of the drive gear 2 and the driven gear 3 have the same twist angle, but the twist direction is opposite. Therefore, when viewed from the side, there is a side closer to the teeth of the pair of gears and a side farther away. The amount of twist of the drive gear 2 and the driven gear 3 is, for example, one gear pitch (in other words, the overlap meshing rate is 1). However, the amount of twist may be larger or smaller than one front pitch.

  In the eyeglass hole 10 formed inside the casing 6, in FIG. 1, a bearing case 11 that supports a drive shaft 4 a extending leftward from the drive gear 2 and a leftward drive from the driven gear 3. A bearing case 111 that supports the extended driven shaft 5a is inserted. Each of the bearing cases 11 and 111 has one support hole, and a bearing 11a that is a bearing of the drive shaft 4a and a bearing 111a that is a bearing of the driven shaft 5a are provided in the support holes. Therefore, the bearing case 11 rotatably supports the drive shaft 4a when the drive shaft 4a is inserted through the bearing 11a, and the bearing case 111 is driven by the driven shaft 5a when the driven shaft 5a is inserted through the bearing 111a. Is supported rotatably.

  Similarly, in the eyeglass hole 10 formed inside the casing 6, in FIG. 1, a bearing case 12 that supports the drive shaft 4 b extending from the drive gear 2 to the right and a right side from the driven gear 3 are provided. A bearing case 112 that supports the driven shaft 5b extending toward is inserted. Each of the bearing cases 12 and 112 has one support hole, and a bearing 12a that is a bearing of the drive shaft 4b and a bearing 112a that is a bearing of the driven shaft 5b are provided in the support holes. Therefore, the bearing case 12 rotatably supports the drive shaft 4b by the drive shaft 4b being inserted into the bearing 12a, and the bearing case 112 is driven by the driven shaft 5b being inserted into the bearing 112a. Is supported rotatably.

  Two side plates 15 a and 15 b are arranged on both sides of the drive gear 2 and the driven gear 3, respectively. The side plate 15a is a plate-like member in which two through holes are formed, and contacts the end surfaces of the drive gear 2 and the driven gear 3 with the drive shaft 4a and the driven shaft 5a inserted through the two through holes. Touch. Similarly, the side plate 15b is a plate-like member in which two through holes are formed, and the drive gear 2 and the driven gear 3 of the drive gear 2 and the driven gear 3 are inserted in a state where the drive shaft 4b and the driven shaft 5b are inserted into the two through holes. Abuts against the end face. Therefore, the side plate 15a is disposed between the drive gear 2 and the driven gear 3 and the bearing cases 11 and 111, and the side plate 15b is disposed between the drive gear 2 and the driven gear 3 and the bearing cases 12 and 112. Placed in.

  An elastic seal member 11b is provided on an end surface of the bearing cases 11 and 111 facing the side plate 15a. The seal member 11b divides a gap between the bearing cases 11 and 111 and the side plate 15a into a high pressure side and a low pressure side. The other end face of the bearing case 11 is in contact with the end face of the mounting 8, thereby restricting the movement of the bearing cases 11 and 111 in the axial direction. Similarly, an elastic seal member 12b is provided on the end surface of the bearing cases 12 and 112 facing the side plate 15b. The seal member 12b divides a gap between the bearing cases 12 and 112 and the side plate 15b into a high pressure side and a low pressure side. The other end surfaces of the bearing cases 12 and 112 are in contact with the end surface of the cover 9, thereby restricting the movement of the bearing cases 12 and 112 in the axial direction.

  In the gear pump 1, a suction side communication path 31 (communication path) communicating with the low pressure space 25 of the spectacle hole 10 is formed on one side surface of the main body 7 as shown in FIG. On the other side, a discharge side communication passage 41 communicating with the high-pressure space 24 of the spectacle hole 10 is formed. The suction side communication path 31 has a suction path 32 (first flow path) communicating with the outside of the main body 7 (casing 6) and a diffusion path 33 (second flow path) having a larger flow path than the suction path 32. The discharge side communication passage 41 has a discharge passage 42 communicating with the outside of the main body 7 (casing 6) and a collecting passage 43 having a larger flow path than the discharge passage 42. The suction passage 32 and the discharge passage 42 are circular holes provided so that their respective axes are positioned at the center between the rotation shafts of the drive gear 2 and the driven gear 3. Further, the suction passage 32 and the discharge passage 42 are provided so as to be positioned at the axial center of the drive gear 2 and the driven gear 3.

  The diffusion passage 33 extends along the axial direction of the drive gear 2 and the driven gear 3 between the low pressure space 25 of the spectacle hole 10 and the suction passage 32, and the low pressure space 25 and the diffusion passage of the spectacle hole 10. An opening 34 extending along the axial direction of the drive gear 2 and the driven gear 3 is formed at the boundary with the shaft 33. The working fluid sucked into the suction passage 32 by the diffusion passage 33 and the opening 34 is diffused in the axial direction of the drive gear 2 and the driven gear 3 in the diffusion passage 33 and then flows into the eyeglass hole 10. The working fluid easily spreads over the entire tooth width of the gear 2 and the driven gear 3. As shown in FIG. 3, the diffusion passage 33 is formed by hollowing out the main body 7 in the axial direction of the drive gear 2 and the driven gear 3 so that the shape of the passage becomes a substantially semi-cylindrical shape in a horizontal sectional view. Further, the opening 34 is opened in the entire axial direction of the drive gear 2 and the driven gear 3.

  The collective passage 43 extends along the axial direction of the drive gear 2 and the driven gear 3 between the high-pressure space 24 of the spectacle hole 10 and the discharge passage 42, and the collective passage 43 and the collective passage 43 of the spectacle hole 10. Is formed with an opening (not shown) extending along the axial direction of the drive gear 2 and the driven gear 3. As shown in FIG. 3, the collective passage 43 is formed by hollowing out the main body 7 in the axial direction of the drive gear 2 and the driven gear 3 so that the shape of the passage is a substantially semi-cylindrical shape in a horizontal sectional view. . This opening is opened in the entire axial direction of the drive gear 2 and the driven gear 3.

  In this gear pump 1, a pipe from a tank that stores the working fluid is connected to the suction passage 32 of the casing 6, and a pipe that is directed to the hydraulic device is connected to the discharge passage 42. 4a is rotated by driving means (not shown). As a result, the driven gear 3 meshed with the drive gear 2 rotates, and the working fluid in the space surrounded by the tooth surfaces of the drive gear 2 and the driven gear 3 and the inner peripheral surface 10a of the eyeglass hole 10 is discharged by the rotation of the gear. It is transferred to the passage 42 side, the discharge passage 42 side becomes the high pressure side, and the suction passage 32 side becomes the low pressure side.

  When the working fluid is transferred to the discharge passage 42 side and the suction passage 32 side becomes negative pressure, the working fluid in the tank passes through the piping and the suction passage 32 and then flows into the diffusion passage 33 and diffuses to the low pressure side. Is sucked into the eyeglass hole 10. Then, the working fluid in the space surrounded by the tooth surfaces of the drive gear 2 and the driven gear 3 and the inner peripheral surface 10a of the eyeglass hole 10 is transferred to the discharge passage 42 side by the rotation of the gear and is sent to the hydraulic device.

  By the way, when the working fluid is taken into the space surrounded by the tooth surface of the gear and the inner peripheral surface 10a of the eyeglass hole 10 and sent to the high-pressure discharge passage 42 side, the working fluid taken into the space is taken up. In order not to leak to the low-pressure suction passage 32 side, the gear teeth and the inner peripheral surface 10a of the eyeglass hole 10 must be in contact (including a case where they are close to each other with a very narrow gap). . As shown in FIG. 3, when the gear pump 1 is discharging high pressure working fluid, the drive gear 2 and the driven gear 3 are pressed toward the suction passage 32 by the high pressure space 24 on the discharge passage 42 side. The drive gear 2 and the driven gear 3 are close to the suction passage 32 side. Therefore, among the plurality of tooth tips of the drive gear 2 and the driven gear 3, the tooth tips that are in contact with the inner peripheral surface 10a of the eyeglass hole 10 are the tooth tips that are located closest to the suction passage 32, and by this tooth tip, The working fluid is prevented from leaking to the suction passage 32 side.

[Details of opening]
Next, details of the opening 34 formed at the boundary between the eyeglass hole 10 and the diffusion passage 33 will be described with reference to FIGS. Here, FIG. 5 is a diagram for explaining the shape of the opening 34, and is an enlarged view of a portion where the tooth tip abuts when the suction passage 32 is viewed from the inside of the eyeglass hole 10. FIG. 6 is a diagram for comparing the opening 34 of the gear pump according to the embodiment of the present invention and the opening of the gear pump according to the comparative example. FIG. 7 is a diagram for explaining a change in the depth of the diffusion passage 33 in the axial direction of the drive gear 2 and the driven gear 3. Here, in FIG. 5 to FIG. 7, a range “b” in the figure indicates a width at which the tooth tip of the gear comes into contact with the inner peripheral surface of the eyeglass hole. 5 and 6 show only the tooth width of the gear in the spectacle hole in the axial direction of the gear.

  As shown in FIG. 5, when the opening 34 is viewed from the inside of the eyeglass hole 10 to the suction passage 32 (first flow path) side, the teeth that are located closest to the suction passage 32 side of the pair of helical gears. The opening width W2 on the far side (the right side of the drive gear 2 and the driven gear 3) of the tooth trace (the tooth traces 51 and 61 in the tooth tip cylinders of the drive gear 2 and the driven gear 3) is closer to the side of the tooth trace (drive). The opening width W1 of the gear 2 and the driven gear 3) is made wider. Here, "the opening width on the far side of the pair of helical gears is wider than the opening width on the side on which the pair of helical gears approaches" means that the tooth line is closest ( (The left end of the drive gear 2 and the driven gear 3) has the narrowest opening width, and there is a portion where the opening width is wider than the opening width of the portion closest to the tooth streak in the direction from the side closer to the tooth streak Means that.

  In the opening 34, both end portions 35 and 36 in the width direction have one step portion 35 </ b> A and 36 </ b> A, respectively, so that the opening width W <b> 2 on the side where the tooth trace is far is wider than the opening width W <b> 1 on the side where the tooth trace approaches. Has been. As shown in FIG. 5, the step portions 35 </ b> A and 36 </ b> A are arranged, for example, at the same position in the axial direction of the gear. Further, the step portions 35A and 36A are arranged on the side closer to the tooth line than the axial center of the suction passage 32 in the axial direction of the gear. Therefore, the opening area of the suction passage 32 is made as large as possible. The opening width W1 and the opening width W2 are narrower than the width D (diameter) of the suction passage 32. As shown in FIG. 7, the depth W4 from the opening 34 on the side where the spiral of the pair of helical gears is farther is deeper than the depth W5 from the opening 34 on the side where the tooth is approaching.

  Here, the tooth trace 51 indicates the tooth trace in the tooth tip cylinder of the drive gear 2 when it is closest to the opening 34 within the sealable range, and the tooth trace 61 is closest to the opening 34 within the sealable range. The tooth trace in the tooth tip cylinder of the driven gear 3 is shown. As shown in FIG. 5, when the left ends of the tooth traces 51 and 61 substantially coincide with the left ends of both ends 35 and 36 in the width direction of the opening 34, the entire area of the opening 34 is inside the tooth trace 51 and the tooth trace 61. An opening 34 is formed so as to fit in the space. Therefore, when the left ends of the tooth traces 51 and 61 substantially coincide with the left ends of both ends 35 and 36 in the width direction of the opening 34, the opening 34 surrounds the tooth surface of the gear and the inner peripheral surface 10 a of the eyeglass hole 10. The working fluid is prevented from leaking from the space, and the seal region is located as close to the suction passage 32 side as possible (the axial center side of the suction passage 32).

  In this gear pump 1, the opening width W2 on the side where the tooth trace is farther is made wider than the opening width W1 on the side where the tooth streak is approached, and an area not used for the seal on the far side is utilized (the opening By doing so, the area of the opening 34 is increased while bringing the seal region on the side where the teeth of the pair of helical gears approach each other as close as possible to the suction passage 32 side. As shown in FIG. 6, for example, when the opening width is constant in the axial direction, the area (S1) of the opening is made the same as the area (S1) of the opening 34 of the present embodiment as in Comparative Example 1. In this case, the opening width W3 of the opening in the comparative example 1 is larger than the opening width W1 at the left end of the opening 34 in the present embodiment. Accordingly, the seal region is separated from the suction passage 32 correspondingly, and the working fluid is likely to leak to the suction passage 32 side from the space surrounded by the gear tooth surface and the inner peripheral surface 10a of the eyeglass hole 10. Similarly, when both ends in the width direction of the opening are constant in the axial direction, the opening width of the opening is made the same as the opening width W1 at the left end of the opening 34 of the present embodiment as in Comparative Example 2. Since the area S2 of the opening in the comparative example 2 becomes smaller than the area S1 of the opening 34 in the present embodiment, there is a possibility that the maximum number of rotations of the gear cannot be secured above a predetermined value. On the other hand, in this embodiment, since the opening width W1 at the left end of the opening 34 is narrow, the area (S1) of the opening 34 is the same as that in Comparative Example 1 while bringing the seal region as close to the suction passage 32 as possible. Can be.

<Characteristics of the gear pump according to this embodiment>
The gear pump 1 according to the present embodiment has the following characteristics.

  In the gear pump 1 according to the present embodiment, the opening width W2 on the side where the teeth of the pair of helical gears are farther is wider than the opening width W1 on the side where the teeth of the pair of helical gears approach, By utilizing the area where the tooth traces of the pair of helical gears are not used for the seal on the far side, the seal area on the side where the tooth traces of the pair of helical gears approach is viewed from the eyeglass hole 10 side as much as possible. The area of the opening 34 was enlarged while approaching the 1 flow path (suction passage 32) side. As a result, the working fluid is prevented from leaking from the space surrounded by the tooth surface of the helical gear and the inner peripheral surface 10a of the eyeglass hole 10 to the first flow path (suction passage 32), and cavitation occurs. It can be prevented from occurring. Therefore, it can prevent that the efficiency of a gear pump falls. Moreover, in the gear pump 1 according to the present embodiment, the diffusion passage 33 (second flow path) is provided on the side where the teeth of the pair of helical gears are far away, and on the side where the teeth of the pair of helical gears are far away. The depth W4 from the opening 34 is deeper than the depth W5 from the opening 34 on the side where the helical gears of the pair of helical gears are close to each other. The flow path volume of the second flow path (diffusion path 33) can be increased. Therefore, the pressure loss of the working fluid can be reduced, and the occurrence of cavitation can be further prevented.

  In the gear pump 1 according to the present embodiment, the opening width W1 on the side where the teeth of the pair of helical gears approach is narrower than the width D (diameter) of the first flow path (suction passage 32). The seal area where the gear teeth and the inner peripheral surface 10a of the eyeglass hole 10 abut can be brought closer to the first flow path (suction passage 32) side.

[Second Embodiment]
Next, a gear pump according to a second embodiment will be described with reference to FIG. In FIG. 8, a range “b” in the figure indicates a width in which the tooth tip of the gear contacts the inner peripheral surface of the eyeglass hole.

  As shown in FIG. 8, the opening 44 of the gear pump of the present embodiment is similar to the first embodiment in that the teeth of the teeth that are located closest to the suction passage 32 of the pair of helical gears (drive gear) 2 and the opening width W12 on the side where the tooth traces 51, 61) of the tooth tip cylinders of the driven gear 3 are farther are wider than the opening width W11 on the side where the tooth trace approaches. Moreover, the opening width of the opening 44 changes so as to follow the tooth trace in the tooth tip cylinder of the pair of helical gears. More specifically, both ends 45 and 46 in the width direction of the opening 44 have inclined portions 45A and 46A that are inclined so as to follow the tooth traces in the tooth tip cylinder of the pair of helical gears. Further, linear portions 45B and 46B having a constant opening width in the axial direction of the gear are formed on the side farther from the inclined portions 45A and 46A. As a result, it is possible to prevent the strength of the main body 7 (casing 6) from being lowered due to the opening width becoming too wide on the side where the tooth trace is far away. The opening width W11 is narrower than the width (diameter) of the suction passage 32. Although not shown, the depth of the pair of helical gears from the opening 44 on the side where the tooth traces are far away is made deeper than the depth from the opening 44 on the side where the teeth are approaching.

<Characteristics of the gear pump according to this embodiment>
The gear pump according to the present embodiment has the following characteristics.

  In the gear pump according to the present embodiment, the opening width of the opening 44 changes so as to follow the tooth trace in the tooth tip cylinder of the helical gear, so that the area of the opening 44 can be efficiently increased.

  Further, in the gear pump according to the present embodiment, the width direction both ends 45 and 46 of the opening 44 are inclined so as to follow the tooth streaks in the tooth tip cylinder of the helical gear. Can be enlarged efficiently.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes meanings equivalent to the scope of claims for patent and all modifications within the scope.

  In the first and second embodiments described above, the case where there is no portion in which the opening width becomes narrower in the direction toward the far side from the side where the pair of helical gears approaches is described. If there is a part with a wider opening width than the opening width of the end in the direction toward the side farther from the side where the tooth trace approaches, the side farther from the side where the tooth trace approaches There may be a portion where the opening width becomes narrower in the direction toward.

  In the first and second embodiments described above, the case where the opening is in the entire tooth width of the helical gear has been described. However, the opening is not necessarily in the entire tooth width.

  Further, in the first embodiment described above, a case where both ends in the width direction of the opening have a step will be described, and in the second embodiment described above, both ends in the width direction of the opening are respectively along the gear teeth. However, the step or inclination is formed only at one end in the width direction of the opening, and the other end in the width direction of the opening extends in the axial direction of the helical gear. It may be.

  In the first and second embodiments described above, the case where the opening width of the pair of helical gears on the side where the tooth traces approach is narrower than the width (diameter) of the suction passage (first flow path) has been described. However, it may be the same as or wider than the width (diameter) of the suction passage (first flow path). Further, the opening width on the side where the tooth trace approaches may be zero.

  In the above-described first embodiment, the description has been given of the case where the opening width on the far side of the pair of helical gears is narrower than the width (diameter) of the suction passage (first flow path). It may be the same as or wider than the width (diameter) of the passage (first flow path).

  In the second embodiment described above, as an example in which the opening width changes along the tooth trace in the tooth tip cylinder of the helical gear, the end in the width direction of the opening is in the tooth tip cylinder of the helical gear. In the present invention, the case where the opening is inclined so as to be along the tooth trace is described. In the present invention, “the opening width changes along the tooth trace in the tooth tip cylinder of the helical gear” means that the end of the opening in the width direction. This is not limited to the case where the portion is inclined so as to follow the tooth trace in the tooth tip cylinder of the helical gear, so that the widthwise end of the opening follows the tooth stripe in the tooth tip cylinder of the helical gear. It may be formed in a step shape (at least two steps).

  Further, in the first and second embodiments described above, the diffusion path (second flow path) has a depth from the opening on the side farther away from the teeth of the pair of helical gears, and the opening on the side closer to the teeth. The depth from the opening has been described, but the depth from the opening may be the same, or the depth from the opening on the side where the pair of helical gears is far away is closer to the tooth line. It may be shallower than the depth from the opening on the side.

  In the second embodiment described above, both end portions in the width direction of the opening 44 have straight portions (straight portions 45B and 46B), but the entire region of both end portions in the width direction of the opening is inclined along the teeth. May be.

  In the first and second embodiments described above, the case where hydraulic oil is used as the working fluid has been described. However, other fluid (for example, water) may be used as the working fluid.

  In the first and second embodiments described above, the case where the present invention is applied to a gear pump has been described. However, the present invention may be applied to a gear motor configured similarly to the gear pump. Accordingly, the working fluid is prevented from leaking from the space surrounded by the tooth surface of the helical gear and the inner peripheral surface of the spectacle hole to the first flow path (suction passage) side, and the second flow path ( It is possible to prevent the pressure loss in the diffusion passage) from increasing.

  If this invention is utilized, it can prevent that the efficiency of a gear motor or a motor falls.

DESCRIPTION OF SYMBOLS 1 Gear pump 2 Drive gear 3 Driven gear 6 Casing 10 Glasses hole 24 High pressure space 25 Low pressure space 31 Suction side communication path (communication path)
32 Suction passage (first flow path)
33 Diffusion passage (second passage)
34, 44 Opening 35, 36, 45, 46 End in width direction

Claims (5)

A casing having glasses holes;
A pair of helical gears that are housed in the eyeglass holes and that abut against the inner peripheral surface of the eyeglass holes to partition the eyeglass holes into a high-pressure space and a low-pressure space;
A communication path communicating with the low-pressure space of the glasses hole,
The communication path is
A first flow path that opens to the outside of the casing;
A second passage that extends along the axial direction of the helical gear between the low-pressure space of the eyeglass hole and the first passage, and has a larger passage than the first passage. And
An opening extending along the axial direction of the helical gear is formed at the boundary between the low-pressure space of the glasses hole and the second flow path,
When the opening looks at the first flow path side from the glasses hole,
A gear pump or motor characterized in that the opening width of the pair of helical gears on the far side is wider than the opening width on the side of the pair of helical gears.   2. The gear pump or motor according to claim 1, wherein the opening width of the pair of helical gears on the side where the tooth traces approach is narrower than the width of the first flow path. The opening is
The gear pump or motor according to claim 1 or 2, wherein the opening width changes so as to follow the tooth trace in the tooth tip cylinder of the helical gear. The widthwise end of the opening is
The gear pump or motor according to claim 3, wherein the helical gear is inclined so as to follow a tooth trace in a tooth tip cylinder of the helical gear. The second flow path is
The depth from the opening on the far side of the pair of helical gears is deeper than the depth from the opening on the side where the pair of helical gears approaches. The gear pump or motor in any one of claim | item 1-4.

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