JP5654717B1 - Hydraulic device - Google Patents

Abstract

The first gear 10 and the second gear 15 that mesh with each other, the main body 3 having the hydraulic chamber 4 in which the first gear 10 and the second gear 15 are accommodated, and the first and second of the first gear 10. Bearing members 20 and 25 that rotatably support the rotary shafts 11 and 12 and the first and second rotary shafts 16 and 17 of the second gear 15 and both end surfaces of the main body 3 are fixed in a liquid-tight manner. A front cover 5 and an end cover 7 are provided, and a meshing thrust force received by meshing and a pressure-receiving thrust force received by the high-pressure side working fluid act on the first gear 10 in the same direction. A meshing thrust force and a pressure-receiving thrust force acting on the first gear 10 when the first gear 10 rotates in the forward rotation direction with respect to at least one of the first and second rotating shafts 11 and 12 of the first gear 10. A first force applying mechanism 40 that applies a drag force against the resultant force of the meshing thrust force and the pressure-receiving thrust force that acts on the first gear 10 when rotating in the reverse rotation direction. Provide.

Description

  The present invention relates to a hydraulic apparatus including a pair of helical gears whose tooth surfaces mesh with each other, and more specifically, a usage mode in which a helical gear is rotated in the forward direction about its axis, and a reverse direction. It is related with the hydraulic apparatus which can be used conveniently in both aspects of the use aspect rotated to 1).

  In the hydraulic device, a pair of gears is appropriately rotated by a drive motor, and a hydraulic pump that pressurizes and discharges the working liquid by a rotating operation of the gears, or a pressurized hydraulic fluid is introduced to introduce the gears. There are hydraulic motors that rotate and use the rotational force of the rotating shaft as power.

  In general, the hydraulic device has a pair of gears meshing with each other housed in a housing, and rotating shafts extending outward from both end surfaces of the gears are housed in the housing. A structure is provided that is rotatably supported by bearing members disposed on both sides of each gear.

  Conventionally, a pair of gears of various shapes are used, and among them, there is a hydraulic device using a helical gear. Although this helical gear has a structure in which the teeth are inclined obliquely, the tooth contact of the gear is dispersed, so that it has a characteristic that the noise is low. On the other hand, this is used as a hydraulic device. In this case, there is a characteristic that an axial thrust force (meshing thrust force) is generated by the meshing of the teeth, and a thrust force (pressure receiving thrust force) is similarly generated by receiving the pressure of the working liquid on the tooth surface.

  This thrust force is periodically changed by the rotation of the gear, and this periodic change causes the gear and the bearing member to vibrate and generates noise, or the vibration causes the end face of the gear and the end face of the bearing member to be generated. A problem arises in that a gap is formed between the two and a leak from the high pressure side toward the low pressure side is caused through the gap.

  Therefore, in order to solve such a problem, a liquid configured to restrain displacement in the axial direction of the gear by applying a force (resistance force) in the opposite direction exceeding the thrust force to each rotating shaft. A pressure device (specifically, a gear pump) has been proposed (see US Pat. No. 6,888,055 (Patent Document 1)). The structure of the gear pump described in this patent document 1 is shown in FIG.

  As shown in FIG. 12, the gear pump 100 includes a main body 101 in which a hydraulic chamber 101a is formed and a pair of helical screws inserted into the hydraulic chamber 101a in a state where teeth are engaged with each other. Gears 115 and 120 are provided. The pair of gears 115 and 120 is configured such that the gear 115 is a driving gear and the gear 120 is a driven gear, and the rotation shafts 116 and 121 are similarly supported by bearings 110a, 110b, 110c, and 110d inserted into the hydraulic chamber 101a. Are supported rotatably.

  Further, a front cover 102 is fixed on the front end surface of the main body 101 in a liquid-tight manner by a seal, while an intermediate plate 106 is fixed on the rear end surface of the main body 101 in a liquid-tight manner by a seal. Similarly, a rear cover 104 is fixed to the rear end surface of the intermediate plate 106 in a liquid-tight manner by a seal. Thus, the main body 101, the front cover 102, the intermediate plate 106, and the rear cover 104 constitute a housing in which the hydraulic chamber 101a is sealed.

  The hydraulic chamber 101a is divided into a high pressure side and a low pressure side with a meshing portion of the pair of gears 115 and 120 as a boundary, and the drive gear 115 is driven to rotate by a driving source as appropriate, so that the pair of gears 115 is driven. , 120 is rotated about its axis, the working liquid is introduced into the low-pressure side from an intake port (not shown), and the introduced working liquid is guided to the high-pressure side while being pressurized by the action of the pair of gears 115, 120, The working liquid that has become is discharged from a discharge port (not shown).

  The intermediate plate 106 has through holes 106a and 106b in portions corresponding to the rotary shafts 116 and 121, and pistons 108 and 109 are inserted into the through holes 106a and 106b, respectively. Yes. In addition, a concave hydraulic chamber 104a corresponding to a region including the through holes 106a and 106b is formed on a surface (front surface) of the rear cover 104 that contacts the intermediate plate 106. The concave hydraulic chamber 104a is appropriately formed in the hydraulic chamber 104a. The high-pressure side working liquid is supplied through a flow path. Further, a high-pressure side working liquid is supplied between the front surface of the intermediate plate 106 and the rear surfaces of the bearings 110a and 110c as appropriate.

  According to the gear pump 100 having the above configuration, during the operation of the gear pump 100, the high-pressure side working liquid is supplied to the hydraulic pressure chamber 104a of the rear cover 104, and the pistons 108 and 109 are respectively caused by the high-pressure working liquid. The gears 115 and 120 are pressed forward by the pistons 108 and 109 via the rotating shafts 116 and 121 by the pistons 108 and 109, and the front surface of the intermediate plate 106 and the rear surfaces of the bearings 110a and 110c. The bearings 110a and 110c are respectively pressed forward by the high-pressure working liquid supplied therebetween, and the bearings 110a and 110c, the gears 115 and 120, and the bearings 110b and 110d are integrally pressed forward by these actions. The bearings 110b and 110d are pressed against the rear end surface of the front cover 102.

As shown in FIG. 12, in this gear pump 100, when the drive gear 115 is rotated in the direction of the arrow, a pressure receiving thrust force F _pa and a meshing thrust force F _ma directed toward the piston 108 are generated in the drive gear 115. , the driven gear 120, the pressure receiving thrust force directed to the piston 109 side _{F pa} and the thrust force _{F ma} meshing thereof toward the opposite occurs. The pressing force that integrally presses the structure including the bearings 110a and 110c, the gears 115 and 120, and the bearings 110b and 110d in the forward direction is set to exceed the thrust force generated by the rotation of the gears 115 and 120. Yes. The pressure receiving areas (cross-sectional areas) of the pistons 108 and 109 are set according to the thrust force acting on the drive gear 115 and the driven gear 120, and the cross-sectional area of the piston 108 is larger than the cross-sectional area of the piston 109. ing.

  As described above, in the hydraulic device using the helical gear, the thrust force generated by the rotation of the helical gear causes vibration and noise, or leaks from the high pressure side to the low pressure side. According to the gear pump 100, the structure including the bearings 110a and 110c, the gears 115 and 120, and the bearings 110b and 110d is integrally pressed forward with a force exceeding the thrust force, and the rear end surface of the front cover 102 is pressed. Therefore, the gears 115 and 120 and the bearings 110a, 110b, 110c, and 110d do not vibrate, and the problem of noise and leakage due to the vibration described above is prevented.

  In addition, as a gear pump using a helical gear, in addition to the gear pump disclosed in Patent Document 1, a gear pump disclosed in Japanese Patent Laid-Open No. 2-95789 (Patent Document 2), A gear pump disclosed in Japanese Utility Model Publication No. 47-16424 (Patent Document 3) is also known.

  In the gear pump disclosed in Patent Document 2, the pressure of the driven fluid is applied to the shaft end surface opposite to the output side of the drive gear, and the thrust force acting on the drive shaft by this pressure and the meshing of the gear The thrust force acting on the drive shaft is offset.

  Further, in the gear pump disclosed in Patent Document 3, similar to the gear pump disclosed in Patent Document 1, a thrust force caused by pressurized liquid is applied to the shaft ends of the drive gear and the driven gear, respectively. The force and the thrust force acting on the drive gear and the driven gear are offset.

US Pat. No. 6,888,055 Japanese Patent Laid-Open No. 2-95789 Japanese Utility Model Publication No. 47-16424

  By the way, for example, in the case of a gear pump applied to a hydraulic servomechanism, it is not a usage mode in which the gear is rotated in a predetermined direction, and the rotation direction of the gear is selectively switched between forward and reverse. The mode of use is taken.

  In this case, the thrust force acting on each gear when each gear of the gear pump is rotated in one direction and the thrust force acting on each gear when rotated in the opposite direction are such that the acting direction is The opposite is true.

For example, taking the gear pump 100 shown in FIG. 12 as an example, as shown in FIG. 12, when the drive gear 115 is rotated in the direction indicated by the arrow D (this direction is the positive direction), As shown, a meshing thrust force [F _ma ] and a pressure receiving thrust force [F _pa ] toward the piston 108 act on the drive gear 115, and a pressure receiving thrust force toward the piston 109 side acts on the driven gear 120. [F _pa ] and the meshing thrust force [−F _ma ] directed to the opposite side act.

On the other hand, when the drive gear 115 of the gear pump 100 is rotated in the direction indicated by the arrow E, that is, in the opposite direction as shown in FIG. Meshing thrust force [−F _ma ] and pressure-receiving thrust force [−F _pa ] directed toward the opposite side act, and the meshing thrust force [F _ma ] directed toward the piston 109 side and the opposite side are applied to the driven gear 120. The pressure receiving thrust force [−F _pa ] directed toward is applied.

  In this way, in the case of a hydraulic device using a helical gear, the thrust force acting on each gear is exactly opposite depending on the rotation direction of the gear.

  However, the conventional gear pump has a structure in which the drag force against the thrust force acting on each gear can be applied only in one direction. In the case of use, however, an appropriate drag can be applied to the thrust force in one rotation direction of the gear, but a drag is applied to the thrust force in the other rotation direction of the gear. There is a problem that the above-mentioned problems due to the thrust force acting on the gear cannot be solved.

  The present invention has been made in view of the above circumstances, and even when a hydraulic device using a helical gear is used in a mode in which the gear is rotated in the forward direction and a mode in which the gear is rotated in the reverse direction, An object of the present invention is to provide a hydraulic device capable of appropriately mitigating the thrust force acting on each gear.

The present invention for solving the above problems is as follows.
A first and a second pair of helical gears having first and second rotating shafts provided so as to extend outward from both end faces, respectively, and the tooth portions mesh with each other;
A hydraulic chamber accommodated in a state where both end portions are open and the first and second gears are engaged with each other; the hydraulic chamber has a main body having an arcuate inner peripheral surface;
A bearing member disposed on each side of the first and second gears in the hydraulic chamber of the main body and rotatably supporting the first and second rotating shafts of the first and second gears;
A front-side front cover and a rear-side end cover, which are fixed in a liquid-tight manner on both end faces of the main body and seal the hydraulic chamber,
The hydraulic chamber is set to one side on the low pressure side and the other side to the high pressure side with the meshing portion of the first and second gears as a boundary,
A meshing thrust force received by the meshing and a pressure receiving thrust force received by the high-pressure side working fluid act in the same direction on the first gear,
The first rotating shaft of the first gear is provided so as to extend outwardly through the front cover, and the first rotating shaft of the second gear is provided on the front cover side. Pressure device,
The meshing thrust force and the pressure-receiving thrust force acting on the first gear when the first gear rotates in the forward rotation direction with respect to at least one of the first and second rotating shafts of the first gear. A first force that acts against the resultant force of the meshing thrust force and the pressure-receiving thrust force that acts on the first gear when the first gear rotates in the reverse rotation direction. The present invention relates to a hydraulic device provided with a drag application mechanism.

  In a hydraulic device using a helical gear, a meshing thrust force is generated by meshing teeth, and a pressure-receiving thrust force is generated by the tooth surface receiving the pressure of the working liquid.

  Of these thrust forces, the pressure-receiving thrust force acts on the tooth surfaces of the pair of gears in the same manner, and thus acts on the pair of gears in the same direction. On the other hand, the meshing thrust force is generated by the meshing of the tooth portions and acts as a reaction force with each other, and thus acts in the opposite direction to the pair of gears. Therefore, for one gear, the meshing thrust force and the pressure-receiving thrust force are in the same direction, and a thrust force as a resultant force of the meshing thrust force and the pressure-receiving thrust force acts on the one gear. For the other gear, the meshing thrust force and the pressure-receiving thrust force are in opposite directions, and a thrust force that is the difference between the meshing thrust force and the pressure-receiving thrust force acts on the other gear.

  Thus, according to this hydraulic device, the meshing thrust force and the pressure-receiving thrust force are applied to the first gear in the same direction, and the meshing force and the pressure-receiving thrust force are applied to the second gear. Acts in the opposite direction. The first rotation shaft of the first gear functions as an input shaft or an output shaft.

  In the hydraulic device according to the present invention, the first gear is unidirectionally (forward rotation direction) with respect to at least one of the first and second rotation shafts of the first gear by the first drag application mechanism. A drag force acting on the first gear when it rotates and resisting the resultant force of the meshing thrust force and the pressure-receiving thrust force is applied, and when the first gear rotates in the reverse rotation direction, it acts on the first gear. Then, a resistance against the resultant force of the meshing thrust force and the pressure-receiving thrust force is applied.

  Thereby, even if the first gear and the second gear rotate in either the forward or reverse direction, a drag force against the thrust force generated in each case can be applied to the first gear. It is possible to prevent various problems caused by the thrust force, for example, problems such as seizure of the bearing members that are in sliding contact with both end faces of the pair of gears, or damage of these members.

As one specific aspect of the first drag application mechanism,
A first cylinder hole formed in the end cover in the extending direction of the second rotating shaft of the first gear;
A first piston fitted into the first cylinder hole and having a front end engaged with a second rotating shaft of the first gear;
The first piston has a front pressure-receiving surface that is formed in a front portion thereof and receives a pressure directed in the rear direction, and a rear pressure-receiving surface that is formed in a rear portion and receives a pressure directed in the front direction. Have
A first cylinder chamber in which the front pressure receiving surface is located and a second cylinder chamber in which the rear pressure receiving surface is located are formed in the first cylinder hole in a state where the first piston is fitted. ,
Further, a high-pressure working fluid is applied to the front pressure-receiving surface of the first piston so as to communicate with the hydraulic chamber and the first cylinder chamber, which become high when the resultant force acts in the forward direction. A first flow path to be
A second hydraulic pressure chamber that communicates with the hydraulic chamber that is high when the resultant force acts in the rearward direction and the second cylinder chamber, and causes a high-pressure working fluid to act on the rear pressure-receiving surface of the first piston. The aspect provided with the flow path can be mentioned.

  According to the first drag application mechanism having this configuration, when the direction in which the resultant force acts is the front direction, high-pressure working liquid is supplied from the hydraulic chamber to the first cylinder chamber through the first flow path. A high-pressure working liquid acts on the front pressure-receiving surface of the first piston, and the first piston is urged backward, and this attachment is applied to the second rotation shaft of the first gear engaged with the first piston. Power is acting. Thereby, the urging | biasing force (resistance force) toward the back which resists the said resultant force acts on a 1st gearwheel.

  On the other hand, when the direction in which the resultant force acts is the backward direction, the high pressure working liquid is supplied from the hydraulic pressure chamber to the second cylinder chamber through the second flow path, and the high pressure is applied to the rear pressure receiving surface of the first piston. The working liquid acts to urge the first piston forward, and this urging force acts on the second rotating shaft of the first gear engaged with the first piston. Thereby, the urging | biasing force (drag) toward the front direction which resists the said resultant force acts on a 1st gearwheel.

  In the case of this aspect, the first piston may be separated between the front pressure receiving surface and the rear pressure receiving surface, and may be configured to contact and separate from each other. Even if configured in this way, when the high-pressure working liquid is supplied to the second cylinder chamber, the rear pressure-receiving surface side is urged forward and comes into contact with the front pressure-receiving surface side, and the front pressure-receiving surface side Thus, the second rotation shaft of the first gear can be biased forward.

As another aspect of the first drag application mechanism,
A second cylinder hole formed in the through hole portion of the front cover through which the first rotation shaft of the first gear passes, and having a diameter larger than the through hole and opened to the first gear side;
A third cylinder hole formed in the end cover so as to face the end surface of the second rotation shaft of the first gear;
A second piston inserted into the third cylinder hole;
A large-diameter member having a ring shape larger in diameter than the outer diameter of the first rotation shaft of the first gear, engaged with the first rotation shaft, and fitted into the second cylinder hole;
A third cylinder chamber, which is a closed space, is formed on the front side of the large-diameter member in the second cylinder hole, and is closed on the rear side of the second piston in the third cylinder hole. A fourth cylinder chamber is formed,
Further, a third hydraulic fluid chamber communicates with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the forward direction, and the third cylinder chamber, and causes a high-pressure working liquid to act on the front end surface of the large-diameter member. A flow path;
A fourth flow path that communicates with the hydraulic chamber that is high when the resultant force acts in the rearward direction and the fourth cylinder chamber, and causes the high-pressure working liquid to act on the rear end surface of the second piston. The aspect provided with these can be mentioned.

  According to the first drag application mechanism having this configuration, when the direction in which the resultant force acts is the front direction, high-pressure working liquid is supplied from the hydraulic chamber to the third cylinder chamber through the third flow path, A high-pressure working liquid acts on the front end surface of the large-diameter member, and the first rotating shaft of the first gear is urged backward. Thereby, the urging | biasing force (drag) toward the back which resists the said resultant force acts on a 1st gearwheel.

  On the other hand, when the direction in which the resultant force acts is the backward direction, the high pressure working liquid is supplied from the hydraulic pressure chamber to the fourth cylinder chamber through the fourth flow path, and the high pressure operation is applied to the rear end surface of the second piston. The liquid acts and the second piston is urged forward, abuts against the end surface of the second rotation shaft of the first gear, and urges the second rotation shaft forward. Thereby, the urging | biasing force (drag) toward the front direction which resists the said resultant force acts on a 1st gearwheel.

As still another aspect of the first drag application mechanism,
A fourth cylinder hole formed in the through hole portion of the front cover through which the first rotation shaft of the first gear passes, and having a diameter larger than the through hole and opened to the first gear side;
A large-diameter member having a ring shape larger than the outer diameter of the first rotating shaft of the first gear, engaged with the first rotating shaft, and fitted into the fourth cylinder hole;
In the fourth cylinder hole, a fifth cylinder chamber, which is a closed space, is formed on the front side of the large diameter member, and a sixth cylinder chamber, which is a closed space, is formed on the rear side of the large diameter member. And
Further, a fifth fluid pressure chamber communicates with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the front direction, and the fifth cylinder chamber, and causes a high-pressure working fluid to act on the front end surface of the large-diameter member. A flow path;
A sixth flow path that communicates with the hydraulic chamber that has a high pressure when the direction in which the resultant force acts is the backward direction and the sixth cylinder chamber, and causes the high-pressure working liquid to act on the rear end surface of the large-diameter member. The aspect provided with these can be mentioned.

  According to the first drag application mechanism of this configuration, when the direction in which the resultant force acts is the front direction, high-pressure working liquid is supplied from the hydraulic chamber to the fifth cylinder chamber through the fifth flow path. A high-pressure working liquid acts on the front end surface of the large-diameter member, and the first rotating shaft of the first gear is urged backward. Thereby, the urging | biasing force (drag) toward the back which resists the said resultant force acts on a 1st gearwheel.

  On the other hand, when the direction in which the resultant force acts is the backward direction, the high pressure working liquid is supplied from the fluid pressure chamber to the sixth cylinder chamber through the sixth flow path, and the high pressure operation is performed on the rear end surface of the large-diameter member. The liquid acts to urge the first rotation shaft of the first gear in the forward direction. Thereby, the urging | biasing force (drag) toward the front direction which resists the said resultant force acts on a 1st gearwheel.

As still another aspect of the first drag application mechanism,
A fifth cylinder hole formed in the end cover along the extending direction of the second rotating shaft of the first gear and into which the second rotating shaft is inserted;
A large-diameter member having a ring shape larger than the outer diameter of the second rotating shaft of the first gear, engaged with the second rotating shaft, and fitted into the fifth cylinder hole;
In the fifth cylinder hole, a seventh cylinder chamber that is a closed space is formed on the front side of the large-diameter member, and an eighth cylinder chamber that is a closed space is formed on the rear side of the large-diameter member. And
Further, a seventh hydraulic fluid chamber communicates with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the forward direction and the seventh cylinder chamber, and causes a high-pressure working liquid to act on the front end surface of the large-diameter member. A flow path;
An eighth flow path that communicates with the hydraulic chamber that becomes high when the direction in which the resultant force acts is the backward direction and the eighth cylinder chamber, and that causes the high-pressure working liquid to act on the rear end surface of the large-diameter member. The aspect provided with these can be mentioned.

  According to the first drag application mechanism of this configuration, when the direction in which the resultant force acts is the front direction, high-pressure working liquid is supplied from the hydraulic chamber to the seventh cylinder chamber through the seventh flow path, A high-pressure working liquid acts on the front end surface of the large-diameter member, and the second rotating shaft of the first gear is urged backward. Thereby, the urging | biasing force (drag) toward the back which resists the said resultant force acts on a 1st gearwheel.

  On the other hand, when the direction in which the resultant force acts is the backward direction, the high pressure working liquid is supplied from the hydraulic pressure chamber to the eighth cylinder chamber through the eighth flow path, and the high pressure operation is performed on the rear end surface of the large-diameter member. The liquid acts to bias the second rotation shaft of the first gear forward. Thereby, the urging | biasing force (drag) toward the front direction which resists the said resultant force acts on a 1st gearwheel.

Further, the first rotating shaft of the first gear according to the present invention may have a stepped shaft shape having a large diameter portion and a small diameter portion in order toward the extending direction. As still another aspect of the first drag application mechanism,
The through-hole portion of the front cover through which the first rotation shaft of the first gear penetrates is larger in diameter than the through-hole through which the small-diameter portion of the first rotation shaft passes, and opens to the first gear side. A sixth cylinder hole that is formed and into which the large-diameter portion of the first rotating shaft is inserted;
A seventh cylinder hole formed in the end cover so as to face the end surface of the second rotation shaft of the first gear;
A third piston fitted into the seventh cylinder hole,
In the sixth cylinder hole, a ninth cylinder chamber, which is a closed space, is formed on the front side of the large-diameter portion of the first rotation shaft, and in the seventh cylinder hole, the third piston is provided. A tenth cylinder chamber, which is a closed space, is formed on the rear side,
Further, a high-pressure working liquid is connected to the front end face of the large-diameter portion of the first rotating shaft, and communicates with the hydraulic chamber that becomes high when the resultant force acts in the forward direction and the ninth cylinder chamber. A ninth flow path for causing
A tenth flow path that communicates with the hydraulic chamber that is high when the direction in which the resultant force acts is the backward direction and the tenth cylinder chamber, and causes the high pressure working liquid to act on the rear end surface of the third piston. The aspect provided with can be taken.

  According to the first drag application mechanism of this configuration, when the direction in which the resultant force acts is the front direction, high-pressure working liquid is supplied from the hydraulic chamber to the ninth cylinder chamber through the ninth flow path, A high-pressure working liquid acts on the front end surface of the large-diameter portion of the first rotating shaft, and the first rotating shaft of the first gear is urged backward. Thereby, the urging | biasing force (resistance force) toward the back which resists the said resultant force acts on a 1st gearwheel.

  On the other hand, when the direction in which the resultant force acts is the backward direction, the high pressure working liquid is supplied from the hydraulic pressure chamber to the tenth cylinder chamber through the tenth flow path, and the high pressure operation is applied to the rear end surface of the third piston. The liquid acts and the third piston is urged forward, abuts against the end surface of the second rotation shaft of the first gear, and urges the second rotation shaft forward. Thereby, the urging | biasing force (drag) toward the front direction which resists the said resultant force acts on a 1st gearwheel.

  In the hydraulic device according to the present invention, the first and second rotating shafts are centered on the shaft in the positive rotation direction with respect to at least one of the first and second rotating shafts of the second gear. When the first and second rotating shafts rotate in the reverse rotation direction, the counteracting force acting on the second gear when it rotates and acting against the resultant force of the meshing thrust force and the pressure-receiving thrust force is applied. You may provide the 2nd force provision mechanism which acts on the 2nd gearwheel and acts the resisting force with respect to the resultant force of the meshing thrust force and the pressure receiving thrust force.

  As described above, the meshing thrust force and the pressure-receiving thrust force act on the second gear in opposite directions. That is, the difference between the meshing thrust force and the pressure receiving thrust force, in other words, the thrust force related to the resultant force of the meshing thrust force and the pressure receiving thrust force acts on the second gear.

  According to the hydraulic device according to the above configuration, the first and second rotating shafts are centered on at least one of the first and second rotating shafts of the second gear by the second drag applying mechanism. A drag acting against the resultant force of the meshing thrust force and the pressure-receiving thrust force acting on the second gear when rotating in the forward rotation direction, and the first and second rotation shafts in the reverse rotation direction. A drag force acting on the second gear when it rotates and acting against the resultant force of the meshing thrust force and the pressure-receiving thrust force is applied.

  As a result, even if the first gear and the second gear rotate in either the forward or reverse direction, a drag force against the thrust force generated in each case can be applied to the second gear. It is possible to prevent various problems caused by the thrust force generated.

As one specific aspect of the second drag application mechanism,
An eighth cylinder hole formed in the front cover in the extending direction of the first rotating shaft of the second gear;
A fourth piston fitted into the eighth cylinder hole and having a rear end engaged with a first rotating shaft of the second gear;
The fourth piston has a front pressure-receiving surface that is formed at a front portion thereof and receives a pressure directed in the rearward direction, and a rear pressure-receiving surface that is formed at a rear portion and receives a pressure directed toward the front. Have
An eleventh cylinder chamber in which the rear pressure receiving surface is located and a twelfth cylinder chamber in which the front pressure receiving surface is located are formed in the eighth cylinder hole in a state where the fourth piston is inserted. ,
Further, a high-pressure working fluid is applied to the rear pressure-receiving surface of the fourth piston so as to communicate with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the backward direction and the eleventh cylinder chamber. An eleventh flow path;
A fluid pressure chamber that is high when the direction in which the resultant force acts is a front direction and a fluid pressure chamber that communicates with the twelfth cylinder chamber and a high-pressure working fluid that acts on the front pressure-receiving surface of the fourth piston. The aspect provided with 12 flow paths can be mentioned.

  According to the second drag application mechanism having this configuration, when the direction in which the resultant force acts is the backward direction, the high-pressure working liquid is supplied from the hydraulic chamber to the eleventh cylinder chamber through the eleventh flow path. A high-pressure working liquid acts on the rear pressure receiving surface of the fourth piston, and the fourth piston is urged forward, and this urging force is applied to the first rotating shaft of the second gear engaged with the fourth piston. Works. Thereby, the urging | biasing force (drag) toward the front which resists the said resultant force acts on a 2nd gearwheel.

  On the other hand, when the direction in which the resultant force acts is the front direction, a high pressure working liquid is supplied from the hydraulic pressure chamber to the twelfth cylinder chamber through the twelfth flow path, and a high pressure is applied to the front pressure receiving surface of the fourth piston. The fourth piston is urged backward, and this urging force acts on the first rotating shaft of the second gear engaged with the fourth piston. Thereby, the urging | biasing force (resistance force) toward the back which resists the said resultant force acts on a 2nd gearwheel.

  In the case of this aspect, the fourth piston may be configured to be separated between the front pressure receiving surface and the rear pressure receiving surface so as to contact and separate from each other. Even if configured in this way, when the high-pressure working liquid is supplied to the twelfth cylinder chamber, the front pressure-receiving surface side is urged rearward, abuts on the rear pressure-receiving surface side, and the rear pressure-receiving surface side is Thus, the first rotation shaft of the second gear can be urged rearward.

Moreover, as another aspect of the second drag application mechanism,
A ninth cylinder hole formed in the end cover in the extending direction of the second rotating shaft of the second gear;
A fifth piston fitted into the ninth cylinder hole and having a front end engaged with a second rotating shaft of the second gear;
The fifth piston has a front pressure-receiving surface that is formed at a front portion thereof and receives a pressure directed in the rearward direction, and a rear pressure-receiving surface that is formed at a rear portion and receives a pressure directed toward the front. Have
In the ninth cylinder hole, a thirteenth cylinder chamber in which the front pressure-receiving surface is located and a fourteenth cylinder chamber in which the rear pressure-receiving surface is located are formed in a state where the fifth piston is fitted. ,
Further, a high-pressure working liquid is applied to the front pressure-receiving surface of the fifth piston so as to communicate with the hydraulic chamber that becomes high when the resultant force acts in the forward direction and the thirteenth cylinder chamber. A thirteenth flow path,
A fourteenth fluid pressure chamber communicates with the fourteenth cylinder chamber, which is high when the direction in which the resultant force acts is the rearward direction, and the fourteenth cylinder chamber, and causes the high pressure working liquid to act on the rear pressure receiving surface of the fifth piston. The aspect provided with the flow path can be mentioned.

  According to the second drag application mechanism of this configuration, when the direction in which the resultant force acts is the front direction, high-pressure working liquid is supplied from the hydraulic chamber to the thirteenth cylinder chamber through the thirteenth flow path. A high-pressure working liquid acts on the front pressure-receiving surface of the fifth piston, and the fifth piston is urged backward, and this attachment is applied to the second rotating shaft of the second gear engaged with the fifth piston. Power is acting. Thereby, the urging | biasing force (resistance force) toward the back which resists the said resultant force acts on a 2nd gearwheel.

  On the other hand, when the direction in which the resultant force acts is the backward direction, the high pressure working liquid is supplied from the hydraulic pressure chamber to the fourteenth cylinder chamber through the fourteenth flow path, and the high pressure is applied to the rear pressure receiving surface of the fifth piston. , The fifth piston is urged forward, and this urging force acts on the second rotating shaft of the second gear engaged with the fifth piston. Thereby, the urging | biasing force (drag) toward the front which resists the said resultant force acts on a 2nd gearwheel.

  In the case of this aspect, the fifth piston may be configured to be separated between the front pressure receiving surface and the rear pressure receiving surface so as to contact and separate from each other. Even if configured in this way, when the high-pressure working liquid is supplied to the twelfth cylinder chamber, the rear pressure-receiving surface side is urged in the forward direction and comes into contact with the front pressure-receiving surface side, and the front pressure-receiving surface side The second rotation shaft of the second gear can be urged forward via the.

As another aspect of the second drag application mechanism,
A tenth cylinder hole formed in the front cover so as to face the end surface of the first rotation shaft of the second gear;
A sixth piston fitted into the tenth cylinder hole;
An eleventh cylinder hole formed in the end cover so as to face the end surface of the second rotation shaft of the second gear;
A seventh piston fitted into the eleventh cylinder hole,
In the tenth cylinder hole, a fifteenth cylinder chamber, which is a closed space, is formed on the front side of the sixth piston, and in the eleventh cylinder hole, on the rear side of the seventh piston. A sixteenth cylinder chamber is formed,
Further, a fifteenth fifteenth fluid is communicated with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the front direction, and the fifteenth cylinder chamber, and a high-pressure working liquid acts on the front end surface of the sixth piston. A flow path;
A sixteenth flow path that communicates with the hydraulic chamber that is high when the resultant force acts in the rearward direction and the sixteenth cylinder chamber, and causes the high pressure working liquid to act on the rear end surface of the seventh piston. The aspect provided with these can be mentioned.

  According to the second drag application mechanism of this configuration, when the direction in which the resultant force acts is the front direction, high-pressure working liquid is supplied from the hydraulic chamber to the 15th cylinder chamber through the 15th flow path, A high-pressure working liquid acts on the front end surface of the sixth piston, and the sixth piston is urged rearward to come into contact with the end surface of the first rotating shaft of the second gear, and this is applied rearward. Rush. Thereby, the urging | biasing force (resistance force) toward the back which resists the said resultant force acts on a 2nd gearwheel.

  On the other hand, when the direction in which the resultant force acts is the backward direction, the high pressure working liquid is supplied from the hydraulic pressure chamber to the sixteenth cylinder chamber through the sixteenth flow path, and the high pressure operation is applied to the rear end surface of the seventh piston. The liquid acts and the seventh piston is urged forward, and abuts against the end surface of the second rotating shaft of the second gear, and urges it forward. Thereby, the urging | biasing force (drag) toward the front which resists the said resultant force acts on a 2nd gearwheel.

  As described above, according to the hydraulic device according to the present invention, the first drag application mechanism causes the first gear and the second gear to rotate in either the forward or reverse direction. A drag force against the thrust force can be applied to the first gear, and problems caused by the thrust force can be prevented from occurring.

  Further, even if the first gear and the second gear are rotated in either the forward or reverse direction by the second drag applying mechanism, the drag that resists the thrust force generated in each case acts on the second gear. Therefore, it is possible to prevent problems caused by the thrust force acting on the second gear.

1 is a cross-sectional plan view showing a hydraulic apparatus according to a first embodiment of the present invention. It is arrow AA sectional drawing of FIG. (A) is the enlarged view which expanded the B section in FIG. 1, (b) is sectional drawing of the arrow CC direction. It is explanatory drawing for demonstrating operation | movement of the 1st drag provision mechanism which concerns on 1st Embodiment. It is the plane sectional view showing the hydraulic device concerning a 2nd embodiment of the present invention. It is explanatory drawing which showed the piston which concerns on the 3rd Embodiment of this invention. It is the fragmentary sectional view which showed the 1st drag provision mechanism which concerns on the 4th Embodiment of this invention. It is the plane sectional view showing the hydraulic equipment concerning a 5th embodiment of the present invention. It is the plane sectional view showing the hydraulic device concerning a 6th embodiment of the present invention. It is the plane sectional view showing the hydraulic equipment concerning a 7th embodiment of the present invention. It is the plane sectional view showing the hydraulic equipment concerning an 8th embodiment of the present invention. It is the plane sectional view showing the conventional hydraulic device. It is the plane sectional view showing the conventional hydraulic device.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. Note that the hydraulic device of this example is a hydraulic pump, and hydraulic oil is used as the hydraulic fluid.

[First Embodiment]
1. Configuration of Hydraulic Pump First, the configuration of the hydraulic pump according to the first embodiment will be described with reference to FIGS. As shown in FIGS. 1 and 2, the hydraulic pump 1 includes a housing 2 in which a hydraulic chamber 4 is formed, and a pair of helical gears (hereinafter referred to as a helical gear) disposed in the hydraulic chamber 4. 10 and 15), a pair of bearings 20 and 25, a pair of side plates 30 and 35, a first drag application mechanism 40, and a second drag application mechanism 60.

  The housing 2 includes a main body 3 in which the hydraulic pressure chamber 4 having a space having a cross-sectional shape of approximately 8 is formed from one end face toward the other end face, and a liquid is formed on the front end face of the main body 3. The front cover 5 is tightly fixed and the end cover 7 is also liquid-tightly fixed to the rear end surface of the main body 3. The hydraulic chamber 4 is closed by the front cover 5 and the end cover 7. Has been. A seal plate 6 is embedded in the rear end surface of the front cover 5, and similarly, a seal plate 8 is embedded in the front end surface of the end cover 7.

  One of the pair of gears 10 and 15 is a drive gear (first gear) 10, and the other is a driven gear (second gear) 15. The tooth portion of the drive gear 10 is right-handed, and the tooth portion of the driven gear 15. Is left-handed. The gear 10 has a first rotary shaft 11 and a second rotary shaft 12 extending from the both end surfaces along the axial direction, respectively. Similarly, the gear 15 has the first rotary shaft 16 from the both end surfaces along the axial direction. And the 2nd rotating shaft 17 is extended. The pair of gears 10 and 15 are inserted into the hydraulic pressure chamber 4 in a state of being engaged with each other, and the outer surface of the tooth tip is in sliding contact with the inner peripheral surface 3a of the hydraulic pressure chamber 4, The hydraulic chamber 4 is divided into a high pressure side and a low pressure side with the meshing portion of the pair of gears 10 and 15 as a boundary. The first rotating shaft 11 of the gear 10 extends outward through a through hole 6 a formed in the seal plate 6 and through holes 5 a and 5 b formed in the front cover 5. The first rotary shaft 11 is fitted into the through holes 5a and 6a, and the oil seal 13 seals between the outer peripheral surface and the inner peripheral surface of the through hole 5b.

  The main body 3 is formed with a first port 3b that communicates with the hydraulic chamber 4 on one side surface, and a second port 3c that communicates with the hydraulic chamber 4 on the other side surface opposite to the first port 3b. Is formed. The first port 3b and the second port 3c are provided such that their respective axes are positioned at the center between the pair of gears 10 and 15.

  The pair of side plates 30 and 35 are plate-like members having two through-holes 31 and 32 and through-holes 36 and 37, respectively, each having a cross-sectional shape of approximately 8 characters. The first rotary shaft 11 of the gear 10 is fitted, the second rotary shaft 12 is fitted in the through hole 36, the first rotary shaft 16 of the gear 15 is fitted in the through hole 32, and the first rotary shaft 12 is inserted in the through hole 37. In a state where the two rotating shafts 17 are fitted and inserted, the gears 10 and 15 are disposed on both sides, respectively, and one end surface thereof is in contact with the entire end surface including the tooth portion of each gear 10 and 15. Yes.

  The bearings 20 and 25 are metal bearings each having two support holes 21 and 22 and support holes 26 and 27 and made of a member having a cross-sectional shape of approximately eight. The first rotation shaft 11 is inserted, the second rotation shaft 12 is inserted into the support hole 26, the first rotation shaft 16 of the gear 15 is inserted into the support hole 22, and the second rotation shaft 17 is inserted into the support hole 27. Are inserted on the outer sides of the pair of side plates 30 and 32, respectively, and rotatably support the first rotary shafts 11 and 16 and the second rotary shafts 12 and 17, respectively.

  Further, the seal plate 6, the bearing 20, the side plate 30, the gear 10 and the gear 15, the side plate 35, the bearing 25, and the seal plate 8 that are sequentially arranged are in contact with each other, and the gears 10, 15, A preload is applied to the side plates 30 and 35 and the bearings 20 and 25, respectively.

  As shown in FIGS. 1 to 3, the first drag applying mechanism 40 is formed on the end cover 7 in the extension direction of the second rotary shaft 12 of the gear 10 in order. A cylinder hole 41 having a diameter larger than the diameter, a cylinder hole 43 having an inner diameter smaller than the inner diameter of the cylinder hole 41, a large-diameter portion 46 fitted into the cylinder hole 41, and the cylinder hole 43. And a piston 45 having a small diameter portion 47.

  The second rotary shaft 12 of the gear 10 has an end portion positioned in the cylinder hole 41 in a state of being fitted into the through hole 8a of the seal plate 8, and an ant formed at the same end portion. By inserting a flange 48 formed at the front end of the piston 45 into the groove 13, the piston 45 and the second rotating shaft 12 are engaged with each other.

  Thus, a cylinder chamber 44 is formed between the bottom of the cylinder hole 43 and the rear end surface of the small diameter portion 47, and a cylinder is formed between the front end surface of the large diameter portion 46 and the rear end surface of the seal plate 8. A chamber 42 is formed.

  Further, as shown in FIG. 2, the cylinder chamber 42 is communicated with the first port 3b by a flow path 50 formed in the end cover 7 and a flow path 51 formed in the main body 3. The chamber 44 is communicated with the second port 3 c by a flow path 52 formed in the end cover 7 and a flow path 53 formed in the main body 3.

  Further, the end cover 7 is formed with a drain hole 49 communicating with a space between the rear end surface of the large diameter portion 46 and the bottom surface of the cylinder hole 41.

  As shown in FIG. 1, the second drag applying mechanism 60 is formed on the front cover 5 in the extension direction of the first rotating shaft 16 of the gear 15, and the diameter of the first rotating shaft 16 is sequentially formed. A large-diameter cylinder hole 61, a cylinder hole 63 whose inner diameter is a blind hole smaller than the inner diameter of the cylinder hole 61, a large-diameter portion 66 inserted into the cylinder hole 61, and a small-diameter portion inserted into the cylinder hole 63 And a piston 65 having 67.

  The first rotary shaft 16 of the gear 15 has an end portion located in the cylinder hole 61 in a state of being fitted into the through hole 6b of the seal plate 6, and an ant formed at the same end portion. By inserting a flange 68 formed at the rear end of the piston 65 into the groove 18, the piston 65 and the first rotating shaft 16 are engaged with each other.

  Thus, a cylinder chamber 64 is formed between the bottom of the cylinder hole 63 and the front end surface of the small diameter portion 67, and a cylinder is formed between the rear end surface of the large diameter portion 66 and the front end surface of the seal plate 6. A chamber 62 is formed.

  As shown in FIG. 2, the cylinder chamber 62 is communicated with the second port 3c by a flow path 70 formed in the front cover 5 and a flow path 71 formed in the main body 3. On the other hand, The chamber 64 is communicated with the first port 3 b by a flow path 72 formed in the front cover 5 and a flow path 73 formed in the main body 3.

  The front cover 5 is provided with a drain hole 69 communicating with a space between the front end surface of the large diameter portion 66 and the bottom surface of the cylinder hole 61.

2. Usage Mode of Hydraulic Pump Next, usage modes of the hydraulic pump 1 having the above configuration will be described.
When the gear 10 of the hydraulic pump 1 of this example is rotated in the direction D indicated by the solid arrow in FIGS. 1 and 2, the first port 3b becomes a suction port and the second port 3c becomes a discharge port. On the other hand, when the gear 10 is rotated in the direction E indicated by the dashed arrow, the second port 3c becomes a suction port and the first port 3b becomes a discharge port. Hereinafter, a usage mode in which the gear 10 is rotated in the arrow D direction and a usage mode in which the gear 10 is rotated in the arrow E direction will be described, taking the case where the hydraulic pump 1 of the present example is applied to a hydraulic servo mechanism as an example. The first port 3b and the second port 3c are each connected to the hydraulic servo mechanism, and the hydraulic pump 1 is filled with hydraulic oil.

a. A mode in which the gear 10 is rotated in the arrow D direction When a drive motor is appropriately connected to the first rotating shaft 11 of the gear 10 and the gear 10 is rotated in the arrow D direction by the drive motor, the gear 10 is engaged. The gear 15 rotates in the direction opposite to that of the gear 10, and the hydraulic oil in the space sandwiched between the inner peripheral surface 3 a of the hydraulic chamber 4 and the teeth of the gears 10 and 15 rotates the gears 10 and 15. Is transferred to the second port 3c side, and the second port 3c side becomes a high pressure and the first port 3b side becomes a low pressure with the meshing portion of the pair of gears 10 and 15 as a boundary, and a hydraulic servo is placed in the first port 3b. The hydraulic oil in the mechanism is sucked, and the hydraulic oil that has become high pressure is discharged from the second port 3c toward the hydraulic servo mechanism.

As described above, the tooth portion of the gear 10 of this example is right-handed, and the tooth portion of the gear 15 is left-handed. Therefore, when the gear 10 is rotated in the direction indicated by the arrow D, a pressure-receiving thrust force [F _pa ] indicated by a solid line directed toward the rear direction generated by the high-pressure hydraulic oil acting on the tooth portion of the gear 10 is indicated in FIG. Then, a meshing thrust force [F _ma ] indicated by a solid line acting in the rearward direction caused by the meshing of the gears 10 and 15 acts, and the resultant force of the pressure receiving thrust force [F _pa ] and the meshing thrust force [F _ma ] Act.

On the other hand, the gear 15 has a pressure-receiving thrust force [F _pa ] indicated by a solid line and a forward direction generated by the meshing of the gears 10 and 15, which are generated when high-pressure hydraulic oil acts on the tooth portion. The meshing thrust force [−F _ma ] indicated by the solid line is applied, and the resultant force of the pressure receiving thrust force [F _pa ] and the meshing thrust force [−F _ma ] is applied. In this example, it is assumed that the relationship between the pressure-receiving thrust force and the meshing thrust force is F _pa > F _ma . Therefore, the resultant force of the pressure receiving thrust force [F _pa ] and the meshing thrust force [−F _ma ] acts on the gear 15 in the backward direction.

In the hydraulic pump 1 of this example, when the hydraulic oil in the second port 3c becomes high pressure, this flows into the cylinder chamber 44 through the flow paths 53 and 52 of the first drag application mechanism 40, and The piston 45 acts on the rear end surface of the small diameter portion 47 of the piston 45, and as shown in FIG. 4A, the piston 45 is urged toward the front direction, and the front end surface of the flange portion 48 is the second rotation shaft 12. Abutting on the front end surface 13a of the dovetail groove 13 is urged forward so as to press the second rotating shaft 12. As a result, an urging force directed in the forward direction against the resultant force of the pressure receiving thrust force [F _pa ] and the meshing thrust force [F _ma ] via the second rotating shaft 12 engaged with the piston 45 ( Drag) acts on the gear 10. Thus, the gear 10 is subjected to a forward drag force against the resultant force of the pressure-receiving thrust force [F _pa ] and the meshing thrust force [F _ma ] by the first drag applying mechanism 40.

The drag by the first drag application mechanism 40 is obtained by multiplying the area of the rear end surface (pressure receiving surface) of the small diameter portion 47 by the pressure of the hydraulic oil, and meshes with the pressure receiving thrust force [F _pa ] and the thrust force [ F _ma ] is sufficient as long as it resists the resultant force, and may be a force equal to the resultant force, a smaller force than the resultant force, or a larger force than the resultant force. It is preferable to have an equal drag.

Further, the high-pressure hydraulic oil in the second port 3 c flows into the cylinder chamber 62 through the flow paths 71 and 70 of the second drag application mechanism 60, and the rear end surface of the large-diameter portion 66 of the piston 65. In the same manner as in the case of the first drag application mechanism 40, the piston 65 is urged forward. As a result, a forward biasing force against the resultant force of the pressure-receiving thrust force [F _pa ] and the meshing thrust force [−F _ma ] via the first rotating shaft 16 engaged with the piston 65. (Drag) acts on the gear 15. Thus, a drag force directed in the forward direction against the resultant force of the pressure receiving thrust force [F _pa ] and the meshing thrust force [−F _ma ] acts on the gear 15 by the second drag applying mechanism 60. .

The drag of the second drag applying mechanism 60 is activated to an effective pressure receiving area of the rear end surface of the large diameter portion 66, that is, an area obtained by subtracting the cross sectional area of the first rotating shaft 16 from the cross sectional area of the large diameter portion 66. The drag force is multiplied by the oil pressure, and this drag force is sufficient if it resists the resultant force of the received thrust force [F _pa ] and the thrust force [−F _ma ]. Either a drag force equal to the resultant force, a drag force smaller than the resultant force, or a drag force greater than the resultant force may be used, but a drag force equal to the resultant force is preferable.

  When high-pressure hydraulic oil is supplied into the cylinder chamber 44, a space between the rear end surface of the large diameter portion 46 and the bottom surface of the cylinder hole 41 from the gap between the small diameter portion 47 and the cylinder hole 43. Although there is a concern that the hydraulic oil leaks, the leaked hydraulic oil is discharged to the outside from the drain hole 49. Similarly, when high-pressure hydraulic oil is supplied into the cylinder chamber 62, the gap between the large diameter portion 66 and the cylinder hole 61 is between the front end surface of the large diameter portion 66 and the bottom surface of the cylinder hole 61. Although there is a concern that the hydraulic oil leaks into the space, the leaked hydraulic oil is discharged from the drain hole 69 to the outside.

b. A mode of rotating the gear 10 in the direction of arrow E When the gear 10 is rotated in the direction of arrow E by the drive motor, the gear 15 meshed with the gear 10 rotates in the opposite direction to the gear 10 and the hydraulic chamber The hydraulic oil in the space sandwiched between the inner peripheral surface 3a of 4 and the tooth portions of the gears 10 and 15 is transferred to the first port 3b side by the rotation of the gears 10 and 15, and the pair of gears 10 and 15 The first port 3b side is at a high pressure and the second port 3c side is at a low pressure at the meshing portion, and the hydraulic oil in the hydraulic servomechanism is sucked into the second port 3c. Discharge from the first port 3b toward the hydraulic servo mechanism.

Further, when the gear 10 is rotated in the direction indicated by arrow E, the pressure receiving thrust force [−F _pa , indicated by a broken line, directed in the forward direction caused by the action of high-pressure hydraulic oil on the tooth portion of the gear 10 is applied. ] And a meshing thrust force [-F _ma ] indicated by a broken line, which is generated in the forward direction by the meshing of the gears 10 and 15, and acts on the pressure thrust force [-F _pa ] and the meshing thrust force [-F _ma]. ] And the resultant force acts.

On the other hand, the gear 15 has a pressure receiving thrust force [−F _pa ] indicated by a broken line and a rearward direction generated by meshing of the gears 10 and 15, which is generated in the forward direction due to the action of high-pressure hydraulic oil on the tooth portion. The meshing thrust force [F _ma ] indicated by the broken line is applied to the pressure, and the resultant force of the pressure-receiving thrust force [−F _pa ] and the meshing thrust force [F _ma ] acts. In this example, the relationship between the pressure-receiving thrust force and the meshing thrust force is F _pa > F _ma , and therefore, the gear 15 has a pressure-receiving thrust force [−F _pa ] and a meshing thrust force [F _ma ]. The resultant force acts in the forward direction.

In the hydraulic pump 1 of this example, when the hydraulic oil in the first port 3b becomes high pressure, this flows into the cylinder chamber 42 through the flow paths 51 and 50 of the first drag application mechanism 40, and The piston 45 acts on the front end surface of the large-diameter portion 46 of the piston 45, and as shown in FIG. 4B, the piston 45 is urged rearward, and the rear end surface of the flange portion 48 is the second rotating shaft 12. The dovetail groove 13 is brought into contact with the rear end surface 13b of the dovetail groove 13 and biased backward so as to retract the second rotary shaft 12. As a result, the second thrust shaft 12 engaged with the piston 45 is directed rearward against the resultant force of the pressure-receiving thrust force [−F _pa ] and the meshing thrust force [−F _ma ]. An urging force (resistance force) acts on the gear 10. Thus, the gear 10 has a drag force directed in the backward direction against the resultant force of the pressure-receiving thrust force [−F _pa ] and the meshing thrust force [−F _ma ] by the first drag applying mechanism 40. Works.

The drag of the first drag application mechanism 40 is activated to an effective pressure receiving area of the front end surface of the large diameter portion 46, that is, an area obtained by subtracting the cross sectional area of the second rotating shaft 12 from the cross sectional area of the large diameter portion 46. The drag force is multiplied by the oil pressure, and this drag force is sufficient as long as it resists the resultant force of the received thrust force [−F _pa ] and the thrust force [−F _ma ]. Either a drag force equal to the resultant force, a drag force smaller than the resultant force, or a drag force greater than the resultant force may be used, but a drag force equal to the resultant force is preferable.

Further, the high pressure hydraulic oil in the first port 3 b flows into the cylinder chamber 64 through the flow paths 73 and 71 of the second drag application mechanism 60, and reaches the front end surface of the small diameter portion 67 of the piston 65. Acts and urges the piston 65 in the rearward direction as in the case of the first drag application mechanism 40. As a result, the urging force directed rearward against the resultant force of the pressure-receiving thrust force [−F _pa ] and the meshing thrust force [F _ma ] via the first rotating shaft 16 engaged with the piston 65. (Drag) acts on the gear 15. Thus, a drag force acting in the backward direction against the resultant force of the pressure-receiving thrust force [−F _pa ] and the meshing thrust force [F _ma ] acts on the gear 15 by the second drag applying mechanism 60. To do.

The drag force generated by the second drag application mechanism 60 is obtained by multiplying the area of the front end surface (pressure receiving surface) of the small diameter portion 67 by the pressure of the hydraulic oil. Similarly to the above, the pressure receiving thrust force [−F _pa ] And meshing thrust force [F _ma ], it is sufficient if it resists the resultant force, either as a force equal to the resultant force, as a drag smaller than the resultant force, or as a drag greater than the resultant force. Although it is good, it is preferable to set the drag equal to the resultant force.

  When high-pressure hydraulic oil is supplied into the cylinder chamber 42, a space between the rear end surface of the large diameter portion 46 and the bottom surface of the cylinder hole 41 from the gap between the large diameter portion 46 and the cylinder hole 41. However, the leaked hydraulic oil is discharged from the drain hole 49 to the outside. Similarly, when high-pressure hydraulic oil is supplied into the cylinder chamber 64, the space between the front end surface of the large diameter portion 66 and the bottom surface of the cylinder hole 61 from the gap between the small diameter portion 67 and the cylinder hole 63. However, the leaked hydraulic oil is discharged from the drain hole 69 to the outside.

3. As described above, in the hydraulic pump 1 of this example, even if the gear 10 rotates in either the arrow D direction or the arrow E direction, in each case, the gear 10 A drag force resisting the acting thrust force can be applied to the gear 10 by the first drag applying mechanism 40, and a drag force resisting the thrust force acting on the gear 15 is applied by the second drag applying mechanism 60. Since it can act on the gear 15, various problems caused by the thrust force, for example, in this example, the side plates 30, 35 that are in sliding contact with both end faces of the pair of gears 10, 15 are seized, or It is possible to prevent the problem that they are damaged.

  Although the first embodiment of the present invention has been described above, the first embodiment can further take the following aspects.

That is, in the above example, the relationship between the pressure-receiving thrust force F _pa acting on the gear 15 and the meshing thrust force F _ma is F _pa > F _ma , but when F _pa <F _ma , the second When the flow path 70 and the flow path 71 communicated with the port 3c are communicated with the cylinder chamber 64, and the flow path 72 and the flow path 73 communicated with the first port 3b are communicated with the cylinder chamber 62. good.

  Also with the second drag applying mechanism 60 configured in this manner, when the gear 10 rotates in the direction indicated by the arrow D, the gear 10 is directed in the backward direction against the thrust force in the forward direction acting on the gear 15. A drag force can be applied to the gear 15, and when the gear 10 rotates in the direction of arrow E, it is directed in the forward direction against the thrust force in the backward direction acting on the gear 15. A drag force can be applied to the gear 15.

  Hereinafter, other embodiments of the present invention will be described.

[Second Embodiment]
FIG. 5 is a plan sectional view showing a hydraulic pump according to the second embodiment of the present invention. As shown in FIG. 5, this hydraulic pump 1A is provided with a second drag application mechanism 60 ′ on the end cover 7 side instead of the second drag application mechanism 60. This is the same as the hydraulic pump 1 according to the first embodiment. Accordingly, the same components as those of the hydraulic pump 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The second drag applying mechanism 60 ′ is formed in the end cover 7 sequentially in the extending direction of the second rotating shaft 17 of the gear 15 and has a cylinder hole 61 having a diameter larger than the diameter of the second rotating shaft 17. ', A cylinder hole 63' that is a blind hole whose inner diameter is smaller than the inner diameter of the cylinder hole 61 ', a large-diameter portion 66' that is inserted into the cylinder hole 61 ', and a small-diameter portion that is inserted into the cylinder hole 63'. And a piston 65 ′ having 67 ′.

  The second rotary shaft 17 of the gear 15 has an end portion located in the cylinder hole 61 ′ in a state of being fitted into the through hole 8 b of the seal plate 8, and is formed at the same end portion. By inserting a flange 68 ′ formed at the front end of the piston 65 ′ into the dovetail groove 19, the piston 65 ′ and the second rotating shaft 17 are engaged with each other.

  Thus, a cylinder chamber 64 ′ is formed between the bottom of the cylinder hole 63 ′ and the rear end surface of the small diameter portion 67 ′, and the front end surface of the large diameter portion 66 ′ and the rear end surface of the seal plate 8 are formed. In the middle, a cylinder chamber 62 'is formed.

Although not particularly shown, when the relationship between the pressure-receiving thrust force F _pa and the meshing thrust force F _ma is F _pa > F _ma , the cylinder chamber 64 ′ is formed in the end cover 7. The cylinder chamber 62 ′ is communicated with the second port 3 c by a flow path and a flow path formed in the main body 3, and the flow path formed in the end cover 7 and the flow path formed in the main body 3. In the case where F _pa <F _ma , on the other hand, the cylinder chamber 64 ′ is formed by the flow path drilled in the end cover 7 and the flow path drilled in the main body 3. While communicating with the first port 3 b, the cylinder chamber 62 ′ is communicated with the second port 3 c through a flow path drilled in the end cover 7 and a flow path drilled in the main body 3.

Thus, according to the hydraulic pump 1A, when the relationship between the pressure-receiving thrust force and the meshing thrust force is F _pa > F _ma , when the gear 10 rotates in the direction indicated by the arrow D, the gear 15 A thrust force is generated in the rearward direction. In this case, high-pressure hydraulic oil is supplied from the second port 3c to the cylinder chamber 64 ′ of the second drag applying mechanism 60 ′, and the gear 15 is moved forward by the piston 65 ′. Drag in the direction acts. On the other hand, when the gear 10 rotates in the direction indicated by the arrow E, a thrust force directed forward is generated in the gear 15. In this case, the first port is provided in the cylinder chamber 62 ′ of the second drag applying mechanism 60 ′. High pressure hydraulic oil is supplied from 3b, and a drag force directed backward by the piston 65 'acts on the gear 15.

In the case of F _pa <F _ma , when the gear 10 rotates in the direction indicated by the arrow D, a thrust force is generated in the gear 15 in the forward direction. In this case, the second drag application mechanism 60 ′ High-pressure hydraulic oil is supplied to the cylinder chamber 62 ′ from the second port 3c, and a drag force directed backward by the piston 65 ′ acts on the gear 15. On the other hand, when the gear 10 rotates in the direction indicated by the arrow E, a thrust force is generated in the rear direction in the gear 15. In this case, the first port is provided in the cylinder chamber 64 ′ of the second drag applying mechanism 60 ′. High pressure hydraulic oil is supplied from 3b, and a drag force directed forward by the piston 65 'acts on the gear 15.

  Thus, even in the hydraulic pump 1A according to the second embodiment, even if the gear 10 rotates in either the arrow D direction or the arrow E direction, it acts on the gear 15 in each case. A drag force against the thrust force can be applied to the gear 15 by the second drag applying mechanism 60 ′.

  In this example as well, as in the first embodiment, it is preferable to provide a drain hole communicating with the space between the rear end surface of the large-diameter portion 66 'and the bottom surface of the cylinder hole 61'. In this case, a space between the rear end surface of the large diameter portion 66 ′ and the bottom surface of the cylinder hole 61 ′ and a space between the rear end surface of the large diameter portion 46 of the first drag application mechanism 40 and the bottom surface of the cylinder hole 41. It is more preferable to provide a common drain hole 49 ′ that communicates with both spaces.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In this aspect, the pistons 45, 65, 65 ′ according to the first and second embodiments are separated between the large diameter portions 46, 66, 66 ′ and the small diameter portions 47, 67, 67 ′, respectively. It is an aspect.

  Even in this case, when the high-pressure hydraulic oil is supplied to the cylinder chambers 44, 64, and 64 ′, the small diameter portions 47, 67, and 67 ′ are pressed forward, and the large diameter portions 46, 66, and 66 are respectively pressed. A drag force can be applied to the second rotation shaft 12 of the gear 10, the first rotation shaft 16 of the gear 15, and the second rotation shaft 17 of the gear 15 via '.

  In this case, the large diameter portions 46, 66, 66 'can take the form shown in FIG. 6 instead of the form in the first and second embodiments. FIG. 6 shows, as a representative, a modification example related to the first drag application mechanism 40 according to the first embodiment.

  The large-diameter portion 74 shown in FIG. 6A is made of a ring-shaped member, and is fitted into a small-diameter portion 12 a formed at the end of the second rotating shaft 12. A retaining ring 75 is fitted in the small diameter portion 12 a behind the large diameter portion 74, and the rearward movement of the large diameter portion 74 is stopped by the retaining ring 75.

  Further, the large diameter portion 76 shown in FIG. 6B is also made of a ring-shaped member, is fitted into the small diameter portion 12 a formed at the end of the second rotating shaft 12, and is The rotary shaft 12 is fixed.

  The large-diameter portion 78 shown in FIG. 6C is made of a cylindrical member, and has a blind hole fitting hole 78a on the front end surface thereof. The fitting hole 78a has a second rotating shaft. 12 is fixed to the second rotary shaft 12 by a bolt 79 in a state in which the small diameter portion 12a formed at the end of 12 is fitted.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. The fourth embodiment relates to a modification of the first drag application mechanism 40 and the second drag application mechanisms 60, 60 ′ according to the first and second embodiments. In addition, although the modified example corresponding to the said 1st resistance provision mechanism 40 is demonstrated as a representative here, the modification similarly comprised can also be employ | adopted about 2nd resistance provision mechanism 60, 60 '. FIG. 7 is an enlarged cross-sectional view showing a B ′ portion corresponding to the B portion in FIG. 1, and is an enlarged cross-sectional view showing a first drag applying mechanism 40 ′ of this example. The same components as those of the drag application mechanism 40 are denoted by the same reference numerals.

  As shown in FIG. 7, the first drag application mechanism 40 ′ includes a large-diameter cylinder hole 41 ′ formed in the end cover 7 sequentially in the extending direction of the second rotation shaft 12 of the gear 10, A piston having a cylinder hole 43 that is a blind hole whose inner diameter is smaller than the inner diameter of the cylinder hole 41 ′, a large diameter portion 46 ′ that is inserted into the cylinder hole 41 ′, and a small diameter portion 47 ′ that is inserted into the cylinder hole 43. 45 ′, and the inner diameter of the cylinder hole 41 ′ is smaller than the outer diameter of the second rotating shaft 12.

  Reference numeral 9 denotes a cup-shaped seal member, which is embedded in the end cover 7 so that the cup bottom surface side seals the opening on the front side of the cylinder hole 41 ′. Further, the rear end portion of the second rotary shaft 12 is fitted into the hole 9b of the seal member 9, and the piston 45 'is formed from the large diameter portion 46' formed in front of the large diameter portion 46 '. In a state where the small-diameter shaft portion 46 a ′ is fitted in a through hole 9 c formed in the bottom portion of the seal member 9, a front flange portion 48 ′ is formed at the rear end portion of the second rotary shaft 12. The dovetail groove 13 is engaged. Reference numeral 49 'denotes a drain hole.

  The cylinder chamber 42 ′ is communicated with the first port 3 b by the flow path 50 formed in the end cover 7 and the flow path 51 formed in the main body 3, similarly to the first drag application mechanism 40. On the other hand, the cylinder chamber 44 is communicated with the second port 3 c by the flow path 52 formed in the end cover 7 and the flow path 53 formed in the main body 3.

  When the high-pressure hydraulic oil is supplied to the cylinder chamber 42 ′, the high-pressure hydraulic oil acts on the front end surface of the large-diameter portion 46 ′ of the piston 45 ′ similarly to the first drag application mechanism 40. Thus, the piston 45 ′ is urged rearward, and the urging force directed rearward acts on the first gear 10 via the second rotating shaft 12 engaged therewith. On the other hand, when high-pressure hydraulic oil is supplied to the cylinder chamber 44, the high-pressure hydraulic oil acts on the rear end surface of the small diameter portion 47 of the piston 45 ', and the piston 45' is urged forward, A forward biasing force is applied to the first gear 10 via the second rotating shaft 12 engaged with the first gear 10.

  Thus, it is needless to explain in detail, and the configuration of the first drag application mechanism 40 ′ also causes the gear 10 to move in the direction indicated by the arrow D and the direction indicated by the arrow E in the same manner as in the first drag application mechanism 40. In any case, a drag force against the thrust force acting on the gear 10 can be applied to the gear 10 in any case.

[Fifth Embodiment]
Next, a fifth embodiment of the present invention will be described. FIG. 8 is a plan sectional view showing a hydraulic pump according to a fifth embodiment of the present invention.

  As shown in FIG. 8, the hydraulic pump 1 </ b> B is provided with a first drag application mechanism 80 having a configuration different from the first drag application mechanism 40 of the hydraulic pump 1 according to the first embodiment, Instead of the drag imparting mechanism 60, a second drag imparting mechanism 90 having a different configuration is provided, and the seal plates 6 and 8 are omitted. The other configurations are related to the first embodiment. Similar to the hydraulic pump 1. Accordingly, the same components as those of the hydraulic pump 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The first drag applying mechanism 80 is provided coaxially with the through hole 5a so as to open at the rear end surface of the front cover 5, and a cylinder hole 81 having a diameter larger than the through hole 5a, and the gear 10 A large-diameter member 83 fitted on the first rotating shaft 11, a cylinder hole 84 formed in the end cover 7 so as to face the end surface of the second rotating shaft 12 of the gear 10, and the cylinder And a piston 85 fitted in the hole 84.

  The large-diameter member 83 has a ring shape having a larger diameter than the outer diameter of the first rotary shaft 11, and movement along the axial direction of the first rotary shaft 11 is performed by retaining rings 83 a provided at both ends thereof. It is regulated. The large-diameter member 83 is inserted into the cylinder hole 81, and a cylinder chamber 82 is formed between the bottom surface of the cylinder hole 81 and the front end surface of the large-diameter member 83. A cylinder chamber 86 is formed between the bottom surface of the cylinder hole 84 and the rear end surface of the piston 85.

  Although not shown, the cylinder chamber 86 is communicated with the second port 3c through a flow path drilled in the end cover 7 and a flow path drilled in the main body 3, and the cylinder chamber 82. Is communicated with the first port 3b by a flow path drilled in the front cover 5 and a flow path drilled in the main body 3.

  The second drag applying mechanism 90 includes a cylinder hole 91 formed in the front cover 5 so as to face the end surface of the first rotation shaft 16 of the gear 15, and a piston 93 fitted into the cylinder hole 91. And a cylinder hole 94 formed in the end cover 7 so as to face the end surface of the second rotary shaft 17 of the gear 15, and a piston 96 fitted into the cylinder hole 94. A cylinder chamber 92 is formed between the bottom surface of the piston 93 and the front end surface of the piston 93, and a cylinder chamber 95 is formed between the bottom surface of the cylinder hole 94 and the rear end surface of the piston 96.

Although not shown, when the relationship between the pressure-receiving thrust force F _pa and the meshing thrust force F _ma is F _pa > F _ma , the cylinder chamber 95 is a flow path formed in the end cover 7. In addition, the cylinder chamber 92 communicates with the second port 3 c by a flow path drilled in the main body 3, and the cylinder chamber 92 is formed by the flow path drilled in the front cover 5 and the flow path drilled in the main body 3. In the case where F _pa <F _ma , the cylinder chamber 92 is connected to the port 3b by the flow path drilled in the front cover 5 and the flow path drilled in the main body 3. The cylinder chamber 95 is communicated with the first port 3 b through a flow path drilled in the end cover 7 and a flow path drilled in the main body 3.

Thus, according to the hydraulic pump 1B, when the relationship between the pressure-receiving thrust force _Fpa and the meshing thrust force _Fma is _Fpa > _Fma , when the gear 10 rotates in the arrow D direction, In the gear 10 and the gear 15, a thrust force is generated in the rearward direction. In this case, high pressure hydraulic oil is supplied from the second port 3 c to the cylinder chamber 86 of the first drag application mechanism 80, and the gear 10 is supplied to the gear 10. Further, a forward drag force acting on the piston 85 acts, and high pressure hydraulic fluid is supplied from the second port 3c to the cylinder chamber 95 of the second drag applying mechanism 90, and the gear 15 is moved forward by the piston 96. Drag in the direction acts. On the other hand, when the gear 10 rotates in the direction indicated by the arrow E, a thrust force directed forward is generated in the gear 10 and the gear 15. In this case, the first force is applied to the cylinder chamber 82 of the first drag application mechanism 80. High pressure hydraulic oil is supplied from the port 3b, and a drag force acting in the backward direction by the large-diameter member 83 acts on the gear 10, and the cylinder port 92 of the second drag application mechanism 90 is applied to the cylinder chamber 92 from the first port 3b. High pressure hydraulic oil is supplied, and a drag force directed backward by the piston 93 acts on the gear 15.

In the case of F _pa <F _ma , when the gear 10 rotates in the direction indicated by the arrow D, a thrust force directed backward is generated in the gear 10, and a thrust force directed forward is generated in the gear 15. In this case, high-pressure hydraulic fluid is supplied from the second port 3c to the cylinder chamber 86 of the first drag application mechanism 80, and a drag force directed forward by the piston 85 acts on the gear 10, and The high pressure hydraulic oil is supplied from the second port 3 c to the cylinder chamber 92 of the second drag application mechanism 90, and a drag force directed backward by the piston 93 acts on the gear 15. On the other hand, when the gear 10 rotates in the direction indicated by the arrow E, a thrust force directed in the forward direction is generated in the gear 10 and a thrust force directed in the rear direction is generated in the gear 15. High pressure hydraulic oil is supplied from the first port 3b to the cylinder chamber 82 of the drag applying mechanism 80, and a drag force acting in the rear direction by the large-diameter member 83 acts on the gear 10, and the second drag applying mechanism. High pressure hydraulic oil is supplied from the first port 3 b to the 90 cylinder chambers 95, and a drag force directed forward by the piston 96 acts on the gear 15.

  Thus, even in the hydraulic pump 1B according to the fifth embodiment, even if the gear 10 rotates in any direction of the arrow D direction and the arrow E direction, it acts on the gear 10 in each case. A drag force against the thrust force can be applied to the gear 10 by the first drag application mechanism 80, and a drag force against the thrust force applied to the gear 15 is applied to the gear 15 by the second drag application mechanism 90. Can act.

[Sixth Embodiment]
Next, a sixth embodiment of the present invention will be described. FIG. 9 is a plan sectional view showing a hydraulic pump according to a sixth embodiment of the present invention. As shown in FIG. 9, the hydraulic pump 1 </ b> C of this example relates to a modification of the hydraulic pump 1 </ b> B according to the fifth embodiment. Accordingly, the same components as those of the hydraulic pump 1B are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, the first rotating shaft 11 of the first gear 10 of the present example has a stepped shaft shape having a large diameter portion 11a and a small diameter portion 11b in order in the extending direction. The large-diameter portion 11a of the first rotating shaft 11 is inserted into a cylinder hole 81 'formed in the front cover 5, and the small-diameter portion 11b is inserted into the through hole 5a.

  A cylinder chamber 82 ′ is formed between the bottom surface of the cylinder hole 81 ′ and the front end surface of the large diameter portion 11 a of the first rotating shaft 11, and the cylinder chamber 82 ′ is formed in the front cover 5. The cylinder chamber 86 communicates with the first port 3 b by a flow path and a flow path drilled in the main body 3, and the cylinder chamber 86 is secondly formed by the flow path drilled in the end cover 7 and the flow path drilled in the main body 3. It communicates with the port 3c. Reference numeral 80 'represents a first drag application mechanism.

  When high-pressure hydraulic oil is supplied to the cylinder chamber 82 ′, the hydraulic oil acts on the front end surface of the large-diameter portion 11a, and the first gear 10 is urged rearward, and the cylinder chamber When high-pressure hydraulic fluid is supplied to 86, this hydraulic fluid acts on the rear end surface of the piston 85, and the first gear 10 is urged forward.

  Thus, it is needless to explain in detail. Also in this hydraulic pump 1C, even if the gear 10 rotates in either the arrow D direction or the arrow E direction, it acts on the gear 10 in each case. A drag force against the thrust force can be applied to the gear 10 by the first drag application mechanism 80 ′, and a drag force against the thrust force applied to the gear 15 can be applied to the gear 15 by the second drag application mechanism 90. Can act on.

[Seventh Embodiment]
Next, a seventh embodiment of the present invention will be described. FIG. 10 is a plan sectional view showing a hydraulic pump according to a seventh embodiment of the present invention. As shown in FIG. 10, the hydraulic pump 1 </ b> D of this example relates to a modification of the hydraulic pump 1 </ b> B according to the fifth embodiment. Accordingly, the same components as those of the hydraulic pump 1B are denoted by the same reference numerals, and detailed description thereof is omitted.

  The hydraulic pump 1D omits the configuration related to the cylinder hole 84, the piston 85, the cylinder chamber 86, and the flow path connecting the cylinder chamber 86 and the second port 3c of the hydraulic pump 1B described above. A cylinder chamber 82a is formed between the bottom surface and the front end surface of the large-diameter member 83. A cylinder chamber 82b is formed between the front end surface of the bearing 20 and the rear end surface of the large-diameter member 83. The first port 3b is communicated with the flow path formed in the front cover 5 and the flow path formed in the main body 3, and the cylinder chamber 82b is formed in the flow path and the main body 3 similarly formed in the front cover 5. The second channel 3c communicates with the established flow path. Reference numeral 80 ″ denotes a first drag application mechanism.

  In the hydraulic pump 1D, when high-pressure hydraulic oil is supplied to the cylinder chamber 82a, the hydraulic oil acts on the front end surface of the large-diameter portion 83, and the first gear 10 is urged rearward. When high-pressure hydraulic oil is supplied to the cylinder chamber 82b, the hydraulic oil acts on the rear end surface of the large-diameter portion 83, and the first gear 10 is urged forward.

  Thus, it is not necessary to describe in detail. Even in this hydraulic pump 1D, even if the gear 10 rotates in either the arrow D direction or the arrow E direction, it acts on the gear 10 in each case. A drag force resisting the thrust force can be applied to the gear 10 by the first drag applying mechanism 80 ″, and a drag force resisting the thrust force acting on the gear 15 can be applied to the gear 15 by the second drag applying mechanism 90. Can act on.

[Eighth Embodiment]
Next, an eighth embodiment of the present invention will be described. FIG. 11 is a plan sectional view showing a hydraulic pump according to an eighth embodiment of the present invention. As shown in FIG. 11, the hydraulic pump 1 </ b> E of this example relates to a modification of the hydraulic pump 1 </ b> D according to the seventh embodiment. Accordingly, the same components as those of the hydraulic pump 1D are denoted by the same reference numerals, and detailed description thereof is omitted.

  The hydraulic pump 1E includes a configuration related to the first drag application mechanism 80 ″ of the hydraulic pump 1D, that is, a cylinder hole 81, cylinder chambers 82a and 82b, a large-diameter member 83 and a retaining ring 83a, and a cylinder chamber 82a. While omitting the flow path communicating with the first port 3b and the flow path communicating the cylinder chamber 82b with the second port 3c, a first drag application mechanism 80A is provided on the end cover 7 side.

  The first drag application mechanism 80A includes a cylinder hole 81 ′ and a support hole 7a that are sequentially formed in the end cover 7 along the extending direction of the second rotating shaft 12 ′ of the first gear 10. And a ring-shaped large-diameter member 83 ′ fitted on the rotary shaft 12 ′. The second rotating shaft 12 'is inserted into the cylinder hole 81', and its rear end is inserted into the support hole 7a. The large-diameter member 83 ′ is inserted into the cylinder hole 81 ′ in a state in which movement along the axial direction is restricted by retaining rings 83a ′ provided at both ends thereof, and a cylinder chamber 82a on the front side thereof. 'Is formed, and a cylinder chamber 82b' is formed on the rear side. The cylinder chamber 82 a ′ communicates with the first port 3 b through a flow path drilled in the end cover 7 and a flow path drilled in the main body 3, and the cylinder chamber 82 b ′ is similarly drilled in the end cover 7. The second port 3 c communicates with the provided channel and the channel formed in the main body 3.

  In the hydraulic pump 1E, when high-pressure hydraulic oil is supplied to the cylinder chamber 82a ′, the hydraulic oil acts on the front end surface of the large-diameter portion 83, and the first gear 10 is urged backward. Then, when high-pressure hydraulic oil is supplied to the cylinder chamber 82b ′, the hydraulic oil acts on the rear end surface of the large-diameter portion 83, and the first gear 10 is urged forward.

  Thus, it is needless to explain in detail. Even in this hydraulic pump 1E, even if the gear 10 rotates in either the arrow D direction or the arrow E direction, it acts on the gear 10 in each case. A drag force resisting the thrust force can be applied to the gear 10 by the first drag applying mechanism 80A, and a drag force resisting the thrust force acting on the gear 15 is applied to the gear 15 by the second drag applying mechanism 90. Can act.

  As mentioned above, although specific embodiment of this invention was described, the aspect which can take this invention is not limited to this at all.

  For example, in the above example, the hydraulic pump is illustrated as an example of the hydraulic device according to the present invention. However, the hydraulic pump is not limited to this and may be another hydraulic device such as a hydraulic motor.

In the above example, the case where the relationship between the pressure-receiving thrust force F _pa acting on the second gear 15 and the meshing thrust force F _ma is F _pa > F _ma or F _pa <F _ma has been described. Depending on the tooth profile of the gear 10 and the second gear, F _pa = F _ma may be obtained. In this case, the second drag application mechanisms 60, 60 'and 90 do not need to be provided.

1 Hydraulic pump (hydraulic device)
2 housing 3 body 3b first port 3c second port 4 hydraulic chamber 5 front cover 7 end cover 10 helical gear (gear, first gear)
11 First rotating shaft 12 Second rotating shaft 15 Helical gear (gear, second gear)
16 First Rotating Shaft 17 Second Rotating Shaft 20, 25 Bearing 40 First Drag Applying Mechanism 41 Cylinder Hole 42 Cylinder Chamber 43 Cylinder Hole 44 Cylinder Chamber 45 Piston 46 Large Diameter Portion 47 Small Diameter Portion 60 Second Drag Applying Mechanism 61 Cylinder Hole 62 Cylinder chamber 63 Cylinder hole 64 Cylinder chamber 65 Piston 66 Large diameter portion 67 Small diameter portion

Claims (13)

A first and a second pair of helical gears having first and second rotating shafts provided so as to extend outward from both end faces, respectively, and the tooth portions mesh with each other;
A hydraulic chamber accommodated in a state where both end portions are open and the first and second gears are engaged with each other; the hydraulic chamber has a main body having an arcuate inner peripheral surface;
A bearing member disposed on each side of the first and second gears in the hydraulic chamber of the main body and rotatably supporting the first and second rotating shafts of the first and second gears;
A front-side front cover and a rear-side end cover, which are fixed in a liquid-tight manner on both end faces of the main body and seal the hydraulic chamber,
The hydraulic chamber is set to one side on the low pressure side and the other side to the high pressure side with the meshing portion of the first and second gears as a boundary,
A meshing thrust force received by the meshing and a pressure receiving thrust force received by the high-pressure side working fluid act in the same direction on the first gear,
The first rotating shaft of the first gear is provided so as to extend outwardly through the front cover, and the first rotating shaft of the second gear is provided on the front cover side. Pressure device,
The meshing thrust force and the pressure-receiving thrust force acting on the first gear when the first gear rotates in the forward rotation direction with respect to at least one of the first and second rotating shafts of the first gear. A first force that acts against the resultant force of the meshing thrust force and the pressure-receiving thrust force that acts on the first gear when the first gear rotates in the reverse rotation direction. A hydraulic device characterized by providing a drag application mechanism. The first drag application mechanism is:
A first cylinder hole formed in the end cover in the extending direction of the second rotating shaft of the first gear;
A first piston fitted into the first cylinder hole and having a front end engaged with a second rotating shaft of the first gear;
The first piston has a front pressure-receiving surface that is formed in a front portion thereof and receives a pressure directed in the rear direction, and a rear pressure-receiving surface that is formed in a rear portion and receives a pressure directed in the front direction. Have
A first cylinder chamber in which the front pressure receiving surface is located and a second cylinder chamber in which the rear pressure receiving surface is located are formed in the first cylinder hole in a state where the first piston is fitted. ,
Further, a high-pressure working fluid is applied to the front pressure-receiving surface of the first piston so as to communicate with the hydraulic chamber and the first cylinder chamber, which become high when the resultant force acts in the forward direction. A first flow path to be
A second hydraulic pressure chamber that communicates with the hydraulic chamber that is high when the resultant force acts in the rearward direction and the second cylinder chamber, and causes a high-pressure working fluid to act on the rear pressure-receiving surface of the first piston. The hydraulic apparatus according to claim 1, further comprising a flow path.   3. The hydraulic device according to claim 2, wherein the first piston is separated between the front pressure receiving surface and the rear pressure receiving surface, and is configured to be able to contact and separate from each other. The first drag application mechanism is:
A second cylinder hole formed in the through hole portion of the front cover through which the first rotation shaft of the first gear passes, and having a diameter larger than the through hole and opened to the first gear side;
A third cylinder hole formed in the end cover so as to face the end surface of the second rotation shaft of the first gear;
A second piston inserted into the third cylinder hole;
A large-diameter member having a ring shape larger in diameter than the outer diameter of the first rotation shaft of the first gear, engaged with the first rotation shaft, and fitted into the second cylinder hole;
A third cylinder chamber, which is a closed space, is formed on the front side of the large-diameter member in the second cylinder hole, and is closed on the rear side of the second piston in the third cylinder hole. A fourth cylinder chamber is formed,
Further, a third hydraulic fluid chamber communicates with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the forward direction, and the third cylinder chamber, and causes a high-pressure working liquid to act on the front end surface of the large-diameter member. A flow path;
A fourth flow path that communicates with the hydraulic chamber that is high when the resultant force acts in the rearward direction and the fourth cylinder chamber, and causes the high-pressure working liquid to act on the rear end surface of the second piston. The hydraulic apparatus according to claim 1, comprising: The first drag application mechanism is:
A fourth cylinder hole formed in the through hole portion of the front cover through which the first rotation shaft of the first gear passes, and having a diameter larger than the through hole and opened to the first gear side;
A large-diameter member having a ring shape larger than the outer diameter of the first rotating shaft of the first gear, engaged with the first rotating shaft, and fitted into the fourth cylinder hole;
In the fourth cylinder hole, a fifth cylinder chamber, which is a closed space, is formed on the front side of the large diameter member, and a sixth cylinder chamber, which is a closed space, is formed on the rear side of the large diameter member. And
Further, a fifth fluid pressure chamber communicates with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the front direction, and the fifth cylinder chamber, and causes a high-pressure working fluid to act on the front end surface of the large-diameter member. A flow path;
A sixth flow path that communicates with the hydraulic chamber that has a high pressure when the direction in which the resultant force acts is the backward direction and the sixth cylinder chamber, and causes the high-pressure working liquid to act on the rear end surface of the large-diameter member. The hydraulic apparatus according to claim 1, comprising: The first drag application mechanism is:
A fifth cylinder hole formed in the end cover along the extending direction of the second rotating shaft of the first gear and into which the second rotating shaft is inserted;
A large-diameter member having a ring shape larger than the outer diameter of the second rotating shaft of the first gear, engaged with the second rotating shaft, and fitted into the fifth cylinder hole;
In the fifth cylinder hole, a seventh cylinder chamber that is a closed space is formed on the front side of the large-diameter member, and an eighth cylinder chamber that is a closed space is formed on the rear side of the large-diameter member. And
Further, a seventh hydraulic fluid chamber communicates with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the forward direction and the seventh cylinder chamber, and causes a high-pressure working liquid to act on the front end surface of the large-diameter member. A flow path;
An eighth flow path that communicates with the hydraulic chamber that becomes high when the direction in which the resultant force acts is the backward direction and the eighth cylinder chamber, and that causes the high-pressure working liquid to act on the rear end surface of the large-diameter member. The hydraulic apparatus according to claim 1, comprising: The first rotation shaft of the first gear has a stepped shaft shape having a large diameter portion and a small diameter portion in order toward the extending direction,
The first drag application mechanism is:
The through-hole portion of the front cover through which the first rotation shaft of the first gear penetrates is larger in diameter than the through-hole through which the small-diameter portion of the first rotation shaft passes, and opens to the first gear side. A sixth cylinder hole that is formed and into which the large-diameter portion of the first rotating shaft is inserted;
A seventh cylinder hole formed in the end cover so as to face the end surface of the second rotation shaft of the first gear;
A third piston fitted into the seventh cylinder hole,
In the sixth cylinder hole, a ninth cylinder chamber, which is a closed space, is formed on the front side of the large-diameter portion of the first rotation shaft, and in the seventh cylinder hole, the third piston is provided. A tenth cylinder chamber, which is a closed space, is formed on the rear side,
Further, a high-pressure working liquid is connected to the front end face of the large-diameter portion of the first rotating shaft, and communicates with the hydraulic chamber that becomes high when the resultant force acts in the forward direction and the ninth cylinder chamber. A ninth flow path for causing
A tenth flow path that communicates with the hydraulic chamber that is high when the direction in which the resultant force acts is the backward direction and the tenth cylinder chamber, and causes the high pressure working liquid to act on the rear end surface of the third piston. The hydraulic apparatus according to claim 1, comprising:   With respect to at least one of the first and second rotating shafts of the second gear, the first and second rotating shafts act on the second gear when rotated in the positive rotation direction about the axis. A meshing thrust force acting on the second gear when the first and second rotating shafts rotate in the reverse rotation direction, while acting against the resultant force of the meshing thrust force and the pressure-receiving thrust force. The hydraulic device according to any one of claims 1 to 7, further comprising a second drag application mechanism that applies a drag force against a resultant force of the pressure-receiving thrust force. The second drag application mechanism is:
An eighth cylinder hole formed in the front cover in the extending direction of the first rotating shaft of the second gear;
A fourth piston fitted into the eighth cylinder hole and having a rear end engaged with a first rotating shaft of the second gear;
The fourth piston has a front pressure-receiving surface that is formed at a front portion thereof and receives a pressure directed in the rearward direction, and a rear pressure-receiving surface that is formed at a rear portion and receives a pressure directed toward the front. Have
An eleventh cylinder chamber in which the rear pressure receiving surface is located and a twelfth cylinder chamber in which the front pressure receiving surface is located are formed in the eighth cylinder hole in a state where the fourth piston is inserted. ,
Further, a high-pressure working fluid is applied to the rear pressure-receiving surface of the fourth piston so as to communicate with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the backward direction and the eleventh cylinder chamber. An eleventh flow path;
A fluid pressure chamber that is high when the direction in which the resultant force acts is a front direction and a fluid pressure chamber that communicates with the twelfth cylinder chamber and a high-pressure working fluid that acts on the front pressure-receiving surface of the fourth piston. The hydraulic apparatus according to claim 8, comprising 12 flow paths.   The hydraulic device according to claim 9, wherein the fourth piston is separated between the front pressure receiving surface and the rear pressure receiving surface and is configured to be able to contact and separate from each other. The second drag application mechanism is:
A ninth cylinder hole formed in the end cover in the extending direction of the second rotating shaft of the second gear;
A fifth piston fitted into the ninth cylinder hole and having a front end engaged with a second rotating shaft of the second gear;
The fifth piston has a front pressure-receiving surface that is formed at a front portion thereof and receives a pressure directed in the rearward direction, and a rear pressure-receiving surface that is formed at a rear portion and receives a pressure directed toward the front. Have
In the ninth cylinder hole, a thirteenth cylinder chamber in which the front pressure-receiving surface is located and a fourteenth cylinder chamber in which the rear pressure-receiving surface is located are formed in a state where the fifth piston is fitted. ,
Further, a high-pressure working liquid is applied to the front pressure-receiving surface of the fifth piston so as to communicate with the hydraulic chamber that becomes high when the resultant force acts in the forward direction and the thirteenth cylinder chamber. A thirteenth flow path,
A fourteenth fluid pressure chamber communicates with the fourteenth cylinder chamber, which is high when the direction in which the resultant force acts is the rearward direction, and the fourteenth cylinder chamber, and causes the high pressure working liquid to act on the rear pressure receiving surface of the fifth piston. The hydraulic apparatus according to claim 8, further comprising a flow path.   The hydraulic device according to claim 11, wherein the fifth piston is separated between the front pressure receiving surface and the rear pressure receiving surface, and is configured to be able to contact and separate from each other. The second drag application mechanism is:
A tenth cylinder hole formed in the front cover so as to face the end surface of the first rotation shaft of the second gear;
A sixth piston fitted into the tenth cylinder hole;
An eleventh cylinder hole formed in the end cover so as to face the end surface of the second rotation shaft of the second gear;
A seventh piston fitted into the eleventh cylinder hole,
In the tenth cylinder hole, a fifteenth cylinder chamber, which is a closed space, is formed on the front side of the sixth piston, and in the eleventh cylinder hole, on the rear side of the seventh piston. A sixteenth cylinder chamber is formed,
Further, a fifteenth fifteenth fluid is communicated with the hydraulic chamber which becomes high when the direction in which the resultant force acts is the front direction, and the fifteenth cylinder chamber, and a high-pressure working liquid acts on the front end surface of the sixth piston. A flow path;
A sixteenth flow path that communicates with the hydraulic chamber that is high when the resultant force acts in the rearward direction and the sixteenth cylinder chamber, and causes the high pressure working liquid to act on the rear end surface of the seventh piston. The hydraulic apparatus according to claim 8, comprising:

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