TW201350681A - Gear pump and motor - Google Patents

Abstract

A gear pump and a motor are provided, which include: an external gear pair including a driving side helical gear and a driven side helical gear engaging with each other; a casing having a gear receiving room for receiving the external gear pair in an inner portion and having a bearing for receiving a driving axis for rotatably supporting the driving-side helical gear and a driven axis for rotatably supporting the driven-side helical gear; a pair of side plate received in the casing and respectively spliced with two side surfaces of each helical gear of the external gear pair; a hydraulic mechanism including a hydraulic room, the hydraulic mechanism squeezes the driving axis and the driven axis on an anti-thrust direction by hydraulic pressure lead to the hydraulic room; a high-pressure working fluid leading route leading working fluid from a high-pressure side to the hydraulic room of the hydraulic mechanism. Then, a squeezing force of the hydraulic mechanism is set to squeeze the driving axis and the driven axis on the anti-thrust direction through a value over a variable maximum thrusting force.

Description

Gear pump and motor

The present invention relates to a gear pump and a motor including an external gear pair and a casing, the external gear pair including a driving gear and a driven gear respectively utilizing mutually meshing helical gears, the casing having a gear for housing the external gear pair therein Storage room.

Conventionally, a gear pump or a motor including an external gear pair and a casing including a drive gear and a driven gear that mesh with each other has been widely used, and the casing has a gear housing chamber that accommodates the external gear pair inside. The drive gear and the driven gear of such a gear pump or motor are mainly spur gears in which teeth parallel to the shaft core are formed. However, in the case where a spur gear is used for the drive gear and the driven gear, there are the following problems. Specifically, the teeth of the drive gear and the teeth of the driven gear are meshed simultaneously throughout the tooth width when engaged. Further, when the teeth of the drive gear mesh with the teeth of the driven gear, the meshing is completed at the same time throughout the tooth width. Thereby, noise or vibration is now generated. In order to solve this problem, a design using a helical gear as a drive gear and a driven gear has been proposed (for example, refer to Patent Document 1).

Such a gear pump or motor has, for example, the configuration shown below. That is, as shown in FIG. 2, it includes: an external gear pair X1 including driving side helical gears that mesh with each other X6 and the driven side helical gear X7; the casing X2 has a gear housing chamber X2a for accommodating the external gear pair X1 therein, and has a drive shaft X8 for pivotally supporting the drive side helical gear X6 and a pivotal support The bearing of the driven shaft X9 of the driven side helical gear X7; the rear bearing case X3a and the front bearing housing X3b are housed in the casing X2, and are respectively spliced to the external gear pair X1. The two side faces X6a, X6b, X7a, and X7b of each of the helical gears X6 and X7 also serve as a pair of side plates; the hydraulic mechanism X4 has hydraulic chambers X41a and X41b, and is hydraulically introduced into the hydraulic chambers X41a and X41b. The drive shaft X8 and the driven shaft X9 and the high-pressure working fluid introduction path X5 are pressed in the reverse thrust direction, and the working fluid is introduced into the hydraulic chambers X41a and X41b of the hydraulic mechanism X4 from the high pressure side. The casing X2 includes a cylindrical main body X23 having the gear housing chamber X2a, a front cover X22 attached to the front side of the main body X23, and a rear cover X24 attached to the back side of the main body X23. The rear side bearing housing X3a is housed inside the main body X23, and serves as a side plate, and pivotally supports the rear end side of the drive shaft X8 and the rear end side of the driven shaft X9; and the rear side bearing housing X3b serves as another The side plate pivotally supports the front end side of the drive shaft X8 and the front end side of the driven shaft X9.

In the state in which the gear pump having the above-described configuration is operated, the thrust load due to the component of the rotational torque and the thrust load due to the hydraulic pressure are generated in the drive side helical gear X6 and the driven side helical gear X7. The thrust load generated by the component of the rotational torque is combined with the thrust load generated by the hydraulic pressure. As a result, as shown in FIG. 2, the drive side helical gear X6 and the driven side helical gear X7 are respectively different in size toward the rear. Thrust load (hereinafter, the direction of the thrust load is referred to as "thrust direction", and the opposite direction is referred to as "anti-thrust direction").

The contact pressure of the rear bearing housing X3a due to the above thrust load becomes large, Therefore, for the purpose of reducing the load, the balance pistons X43a and X43b of the hydraulic mechanism X4 are brought into contact with the rear end sides of the drive shaft X8 and the driven shaft X9, respectively, and the balance is achieved by the hydraulic pressure. As a result, the pressure equalizing pistons X43a and X43b can exert a pressing force proportional to the hydraulic pressure against the above-described thrust load.

However, the above-described hydraulic mechanism X4 is provided for the purpose of balancing the thrust only. Therefore, when the operating conditions fluctuate, the thrust load on the driving side helical gear X6 and the driven side helical gear X7 is uneven and does not occur. Stable situation. At this time, not only the rear side bearing housing X3a and the front side bearing housing X3b are loaded with the thrust load, but also the side surfaces X6a, X6b, X7a, and X7b of the driving side helical gear X6 and the driven side helical gear X7 are displaced, thereby causing work. The leakage of the liquid from the side faces X6a, X6b, X7a, and X7b of the helical gears X6 and X7 is increased, and the volume performance is deteriorated. In order to prevent this from occurring, it is necessary to use a material which is expensive and has high contact strength for each of the bearing housings X3a, X3b, by using a pressure balance of a so-called 3-shaped gasket X31, that is, by a 3-shaped pad. A hydraulic seal region is formed inside the sheet X31, and the rear bearing housing X3a is strongly pushed back to the side surfaces X6a and X7a on the rear side of the drive side helical gear X6 and the driven side helical gear X7 to maintain the performance.

Prior technical literature

Patent literature

Patent Document 1: Japanese Patent Laid-Open No. Hei 5-330330

The present invention has been made in view of the above aspects, and an object of the present invention is to provide a restriction that can eliminate the necessity of using a side plate having high cost and high contact pressure, thereby improving A gear pump or motor that is designed to reduce the cost of parts.

That is, the gear pump and the motor of the present invention are characterized by comprising: an external gear pair including a driving side helical gear and a driven side helical gear that mesh with each other; and a casing having a gear housing chamber for housing the external gear pair therein, and a bearing for accommodating a drive shaft pivotally supporting the drive side helical gear and a driven shaft pivotally supporting the driven side helical gear; a pair of side plates housed in the cover and respectively coupled to the external connection Two sides of each helical gear of the pair of gears; a hydraulic mechanism having a hydraulic chamber, and squeezing the drive shaft and the driven shaft in a reverse thrust direction by using hydraulic pressure introduced into the hydraulic chamber; and a high pressure working fluid introduction path from the high pressure The working fluid is introduced into the hydraulic chamber of the hydraulic mechanism, and the pressing force of the hydraulic mechanism is set to press the drive shaft and the driven shaft in a reverse thrust direction by a value exceeding a maximum value of the varying thrust.

According to the above configuration, the drive shaft and the driven shaft are pressed in the reverse thrust direction by the hydraulic pressure mechanism in a value exceeding the maximum value of the varying thrust force. Therefore, the side plate disposed on the thrust direction side is not received. The influence of the thrust load on the drive side helical gear and the driven side helical gear. Therefore, the side plate disposed on the thrust direction side can be made of a material having a low contact pressure. Further, since both the drive side helical gear and the driven side helical gear are constantly pressed in the reverse thrust direction, the positions of the side surfaces of the drive side helical gear and the driven side helical gear accompanying the pressure fluctuation can be eliminated. The problem of offset.

According to the present invention, it is possible to provide a design capable of eliminating the necessity of using a costly and high-pressure side panel, thereby improving the design for reducing the cost of parts. Freedom gear pump and motor.

P1, PP‧‧‧ gear pump

1. X1‧‧‧ external gear pair

2, X2‧‧‧ cover

2a, X2a‧‧‧ gear storage room

2b‧‧‧Working fluid suction port and working fluid discharge port

3‧‧‧ side panels

3a‧‧‧ rear side panel

3b‧‧‧ front side panel

4, X4‧‧‧ hydraulic institutions

5, X5‧‧‧ high pressure working fluid introduction

6, X6‧‧‧ drive side helical gear

Sides of 6a, 6b, 7a, 7b, X6a, X6b, X7a, X7b‧‧‧ helical gears

7, X7‧‧‧ driven side helical gear

8, X8‧‧‧ drive shaft

9, X9‧‧‧ driven shaft

21‧‧‧ Cover body

End face of 21a‧‧‧

22, X22‧‧‧ front cover

22a‧‧‧ inner surface

23. X23‧‧‧ Subject

24, X24‧‧‧ back cover

25, 26‧ ‧ bearing

25x, 26x‧‧‧ bearing holes

25y, 26y‧‧‧ bushings

31, 32, X31‧‧‧ gasket

41‧‧‧ hydraulic room

41a, 41b, X41a, X41b‧‧‧ hydraulic room

42a, 42b‧‧ ‧ cylinder bore

43a, 43b, X43a, X43b‧‧‧ pressure equalizing piston

X3a‧‧‧ rear bearing housing

X3b‧‧‧ front bearing housing

Fig. 1 is a schematic view showing a gear pump or a motor according to an embodiment of the present invention.

Fig. 2 is a schematic view showing a conventional gear pump or motor.

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

As shown in FIG. 1, the gear pump P1 of the present embodiment includes: an external gear pair 1, including a driving side helical gear 6 and a driven side helical gear 7 that mesh with each other; and a casing 2 that houses the external gear pair 1 therein. The gear housing chamber 2a has a bearing for housing the drive shaft 8 pivotally supporting the drive side helical gear 6 and a driven shaft 9 pivotally supporting the driven side helical gear 7; the pair of rear side plates 3a and The front side plate 3b is housed in the casing 2, and is respectively joined to the side faces 6a, 7a, 6b, and 7b of the respective helical gears 6 and 7 of the external gear pair 1, and the hydraulic mechanism 4 has hydraulic chambers 41a and 41b. And driving the drive shaft 8 and the driven shaft 9 in the reverse thrust direction by the hydraulic pressure introduced into the hydraulic chambers 41a, 41b; and the high-pressure working fluid introduction path 5, and introducing the working fluid from the high-pressure side to the hydraulic mechanism Hydraulic chambers 41a, 41b of 4.

The drive side helical gear 6 and the driven side helical gear 7 constituting the external gear pair 1 are well-known helical gears for such a gear pump. Here, when the teeth of the drive side helical gear 6 and the teeth of the driven side helical gear 7 are operated as a gear pump in the meshing state, the drive side helical gear 6 is subjected to the component of the rotational torque. The thrust load toward the rear causes the driven side helical gear 7 to bear forward The thrust load of the square. Further, the drive side helical gear 6 and the driven side helical gear 7 are subjected to a thrust load toward the rear due to the hydraulic pressure in a state where they are operated as a gear pump. The thrust load generated by the component of the rotational torque is combined with the thrust load generated by the hydraulic pressure. As a result, as shown in FIG. 2, the drive side helical gear 6 and the driven side helical gear 7 are respectively different in size toward the rear. Thrust load. In the present embodiment, the drive side helical gear 6 is integrally provided with the drive shaft 8. The drive shaft 8 extends from the center of the drive side helical gear 6 in the direction of the rotation axis. The drive shaft 8 has one end extending to the outside of the casing 2. Further, the driven side helical gear 7 is also integrally provided with the driven shaft 9. The driven shaft 9 extends from the center of the driven side helical gear 7 in the direction of the rotation axis.

The casing 2 includes a casing body 21, a gear housing chamber 2a having an opening at the front, and a front cover 22 attached to the front side of the casing body 21.

The cover main body 21 is integrally formed with a tubular main body 23 and a rear cover 24 that blocks the rear end of the main body 23, and the cylindrical main body 23 includes the above-described gear storage chamber 2a having a substantially spectacles shape. In the meshed state, the pair of external gears 1, that is, the drive side helical gear 6 and the driven side helical gear 7, and the working fluid suction port and the working fluid discharge port 2b (not shown) are accommodated, and the gear accommodation chamber 2a is communicated with the outside. Further, the main body 23 includes a bearing 25 pivotally supporting the drive shaft 8 and the rear end side of the driven shaft 9 at the rear of the gear housing chamber 2a. Each of the bearings 25 includes a bearing hole 25x that can be fitted into the rear end sides of the drive shaft 8 and the driven shaft 9, respectively, and a bush 25y disposed on the inner circumference of the bearing hole 25x and slidably respectively The drive shaft 8 and the driven shaft 9 are pivotally supported.

The front cover 22 is detachably attached to the cover body 21 by a bolt or the like, and blocks an opening surface of the gear accommodation chamber 2a. Moreover, the front cover 22 includes The bearing 26 of the drive shaft 8 and the front end side of the driven shaft 9 is pivotally supported. Each of the bearings 26 includes a bearing hole 26x that is respectively engageable with the front end sides of the drive shaft 8 and the driven shaft 9, and a bushing 26y that is disposed on the inner circumference of the bearing hole 26x and slidably supports the above Drive shaft 8 and driven shaft 9. The front end of the drive shaft 8 protrudes to the outside of the casing 2 through the bearing hole 26x.

Further, in the present embodiment, the rear side plate 3a is provided to be joined to the side surface 6a on the rear side of the drive side helical gear 6 and the side surface 7a on the rear side of the driven side helical gear 7. The rear side plate 3a has a substantially thin plate shape similar to that used for a spur gear type gear pump. The back surface of the rear side plate 3a is interposed between the segment end faces 21a of the cover body 21 via the 3-shaped spacer 31. Further, the hydraulic seal region formed inside the figure-shaped spacer 31 is set to be narrower than the conventional one. Further, a front side plate 3b is provided to be joined to the side surface 6b on the front side of the drive side helical gear 6 and the side surface 7b on the front side of the driven side helical gear 7. The front side panel 3b is made of a material having a relatively high contact pressure and is in the form of a thin plate. The front surface of the front side panel 3b is a spacer 32 that abuts against the inner surface 22a of the front cover 22. Further, in the present embodiment, the material of the front side panel 3b is different from the material of the rear side panel 3a.

The hydraulic mechanism 4 includes a pair of hydraulic chambers 41a and 41b respectively corresponding to the drive shaft 8 and the driven shaft 9 and formed inside the rear cover 24; pair of cylinder bores 42a and 42b, The hydraulic chambers 41a, 41b are communicated into the casing body 21; and a pair of pressure equalizing pistons 43a, 43b are slidably fitted in the cylinder bores 42a, 42b, respectively; and the respective pressure equalizing pistons are 43a and 43b abut against the corresponding end faces of the drive shaft 8 and the driven shaft 9. The diameters of the pressure equalizing pistons 43a and 43b, in other words, the diameters of the cylinder bores 42a and 42b in which the pressure equalizing pistons 43a and 43b are fitted, are set so as to exceed the maximum value of the varying thrust force to press the drive in the reverse thrust direction. The value of the shaft 8 and the above-described driven shaft 9. Specifically, an example When the pressure of the working fluid is P and the cross-sectional area of the cylinder bore 42a on the drive shaft 8 side is A1, the counterpressure is applied by the pressure F1 of the P×A1 by the pressure equalizing piston 43a on the drive shaft 8 side. Squeeze the above drive shaft in the direction. In the present embodiment, when it is determined by the prior measurement that the thrust received by the drive shaft 8 is varied within the range of 7 to 9, the cylinder hole on the drive shaft 8 side is set so that the above-described pressing force F1 is 10. The cross-sectional area A1 of 42a. When the pressure of the working fluid is P and the cross-sectional area of the cylinder bore 43b on the driven shaft 9 side is A2, the pressure is applied to the reverse thrust direction by the force F2 of P×A2 by the pressure equalizing piston. The above-mentioned driven shaft 9. In the present embodiment, when it is determined by the prior measurement that the thrust received by the driven shaft 9 is within the range of 2 to 4, the pressing force F2 is set to 5 so that the pressing force F2 is set to 5. The cross-sectional area A2 of the cylinder bore 42b.

The high-pressure working fluid introduction path 5 is for introducing the working fluid into the hydraulic chambers 41a and 41b of the hydraulic mechanism 4 from the high pressure side, and is formed in the casing body 21.

Here, when the drive side helical gear 6 and the driven side helical gear 7 are synchronously driven in reverse rotation via the drive shaft 8 of the gear pump P1, the working fluid suction port and the working fluid discharge port are A high and low pressure difference is generated between 2b. At this time, the space inside the main body 23 on which the teeth of the driven side helical gear 6 and the driven side helical gear 7 gradually deviate from each other, that is, the space on the side of the working fluid suction port becomes a low pressure region, and the teeth gradually mesh with each other. The space inside the main body 23, that is, the space on the side of the working fluid discharge port 2b becomes a high pressure region. Further, the pumping action is performed to close the working fluid introduced from the working fluid suction port to a volume which is closed between the tooth top of the driving side helical gear 6 and the driven side helical gear 7 and the gear housing chamber 2a. And it is guided to the working fluid discharge port 2b for discharge. Furthermore, it is needless to say that the gear pump P1 can also function as a gear motor that functions as a motor that The action is to introduce a high-pressure working fluid from the working fluid discharge port 2b, thereby obtaining a rotational torque from the drive shaft 8, driving an external load, and ejecting a working fluid that becomes a low pressure from the working fluid suction port.

As described above, according to the configuration of the gear pump P1 of the present embodiment, the diameters of the cylinder bores 42a and 42b accommodating the pressure equalizing pistons 43a and 43b are set so as to exceed the maximum value of the varying thrust force in the reverse thrust direction. The values of the drive shaft 8 and the driven shaft 9 are such that the rear side plate 3a is not affected by the above-described thrust. Therefore, the rear side panel 3a can be constructed of a material having a low contact strength equivalent to that of a spur gear type gear pump. Further, since the front side plate 3b receives a pressing force from the equalizing pistons 43a and 43b, it is necessary to have a material having a sufficient contact strength. However, the front side plate 3b may be formed of a thin plate. That is, it is possible to eliminate restrictions such as the necessity of using a material which is expensive and has high contact strength among the side plates 3a and 3b, thereby improving the degree of design freedom for reducing the cost of parts. In other words, since the bearing housing including the bearing for inserting the drive shaft and the driven shaft can be omitted, the thrust is received by the thin plate-shaped rear side plate 31 and the front side plate 32, so that the number of parts can be reduced and the manufacturing cost can be reduced. Further, since both the drive side helical gear 6 and the driven side helical gear 7 are pressed in the forward thrust direction, that is, in the reverse thrust direction, the drive side helical gear 6 and the driven force accompanying the pressure fluctuation can be eliminated. The positions of the side faces 6a, 6b, 7a, 7b of the side helical gear 7 are shifted, and the working fluid leaks from the side faces 6a, 6b, 7a, 7b of the gears 6, 7, resulting in a problem of a decrease in volume performance.

Further, in the present embodiment, since the tubular main body 23 and the rear cover 24 that blocks the rear end of the main body 23 are integrally formed as the main body 21, the cylindrical main body 23 includes the above-mentioned gears in the form of substantially glasses. The storage chamber 2a accommodates the external gear pair 1 in an engaged state; and the working fluid suction port and the working fluid discharge port 2b, the gear accommodation chamber 2a is communicated to the outside; therefore, unlike the separate formation, it is impossible to cause leakage of the working fluid from the joint portion of the main body 23 and the rear cover 24, and this aspect can also eliminate the problem of deterioration in volume performance. .

Furthermore, the present invention is not limited to the embodiments described above, and various modifications can be made.

For example, in the above embodiment, the main body includes a main body including a gear housing chamber that houses the pair of external gears, and a rear cover that blocks the rear end of the main body. However, the present invention can also be applied to the main body and the main body. The above rear cover is separately constructed. Further, in a case where the main body is configured separately from the rear cover, the main body and the front cover that blocks the front end of the main body may be integrally formed.

Further, in the above embodiment, the front cover may also be used as the front side plate.

Further, in the above embodiment, the rear side panel and the front side panel are made of different materials, and it is needless to say that the rear side panel and the front side panel can be produced from the same material.

Further, various modifications may be made without departing from the spirit and scope of the invention.

Industrial availability

According to the configuration of the gear pump and the motor of the present invention, it is possible to eliminate the restriction of using a side plate having high cost and high contact pressure, and it is possible to increase the degree of freedom in design for reducing the cost of parts.

P1‧‧‧Gear pump

1‧‧‧External gear pair

2‧‧‧Shell

2a‧‧‧Gear storage room

2b‧‧‧Working fluid suction port and working fluid discharge port

3a‧‧‧ rear side panel

3b‧‧‧ front side panel

4‧‧‧Hydraulic institutions

5‧‧‧High pressure working fluid introduction

6‧‧‧Drive side helical gear

6a, 6b, 7a, 7b‧‧‧ side of helical gear

7‧‧‧ driven side helical gear

8‧‧‧Drive shaft

9‧‧‧ driven shaft

21‧‧‧ Cover body

End face of 21a‧‧‧

22‧‧‧ front cover

22a‧‧‧ inner surface

23‧‧‧ Subject

24‧‧‧ Back cover

25, 26‧ ‧ bearing

25x, 26x‧‧‧ bearing holes

25y, 26y‧‧‧ bushings

31, 32‧‧‧ shims

41a, 41b‧‧‧ hydraulic room

42a, 42b‧‧ ‧ cylinder bore

43a, 43b‧‧‧pressure equalizing piston

Claims (2)

A gear pump includes: an external gear pair including a driving side helical gear and a driven side helical gear that are in mesh with each other; and a casing having a gear housing chamber for housing the external gear pair inside the casing and having a bearing The bearing is configured to receive a drive shaft pivotally supporting the drive side helical gear and a driven shaft pivotally supporting the driven side helical gear; the pair of side plates are received in the cover and respectively coupled to the external connection Two sides of each helical gear of the pair of gears; the hydraulic mechanism has a hydraulic chamber, and the hydraulic drive is introduced into the hydraulic chamber to press the drive shaft and the driven shaft in a reverse thrust direction; and the high pressure working fluid introduction path, The working fluid is introduced into the hydraulic chamber of the hydraulic mechanism from the high pressure side; and the pressing force of the hydraulic mechanism is set to press the drive shaft and the driven shaft in the reverse thrust direction by a value exceeding the maximum value of the varying thrust. A motor comprising: the gear pump according to claim 1; and the hydraulic pressure is introduced into the motor by a working fluid discharge port as a pump to obtain a rotational torque of the motor.