Variable displacement gear pump

Abstract

The utility model provides a variable displacement gear pump which comprises a driving device and two gears meshed with each other, the driving device is connected with one gear and is used for driving the gear to rotate along a first direction or a second direction, and the first direction and the second direction are two opposite directions in the circumferential direction of the gear; the two ends, in the circumferential direction of the gear, of teeth of the gear are provided with a first tooth profile face and a second tooth profile face respectively, and the pressure angle of the first tooth profile face is not equal to the pressure angle of the second tooth profile face. For the two gears engaged with each other, the first tooth profile surfaces of the two gears are oppositely arranged, and the second tooth profile surfaces of the two gears are oppositely arranged. According to the variable-displacement gear pump, the teeth of the gear are arranged to be the first tooth profile surface and the second tooth profile surface with different pressure angles, and the tooth profile surfaces with the same pressure angle in the two meshed gears are matched with each other, so that different displacements can be formed when the gears rotate towards different directions, more use scenes are met, and the application range of the variable-displacement gear pump is widened.

Description

TECHNICAL FIELD

[0001] The utility model relates to gear pump field especially relates to a variable displacement gear pump. BACKGROUND

[0002] The displacement of the gear pump is related to the tooth profile of the gear, and the tooth profile of the gear is usually symmetrical, that is, the pressure angle or modulus of the two tooth profile surfaces of the gear is the same, and the displacement of the gear pump is always the same whether the gear pump rotates forward or reversely, that is, a single gear pump only has one displacement. Figure 1 As shown in the drawings, the conventional spur gear pump 1 uses a spur gear 101, or as shown in the drawings, the helical gear pump 2 adopts a single helical gear 201, and the two gears also have the problem of easy local failure of the gear. Figure 2 The utility model discloses a variable displacement gear pump, which can overcome the defect that a single gear pump only has one displacement and cannot adapt to various application scenarios. TECHNICAL PROBLEM

[0003] The utility model discloses a variable displacement gear pump, which can overcome the defect that a single gear pump only has one displacement and cannot adapt to various application scenarios.

[0004] The utility model discloses a variable displacement gear pump, which can overcome the defect that a single gear pump only has one displacement and cannot adapt to various application scenarios.

[0005] The utility model provides a variable displacement gear pump, it includes drive arrangement and two gears that mesh with each other, drive arrangement is connected with one of gear, is used for driving gear rotates along the first direction or second direction, the first direction with second direction is two opposite directions on the circumference of gear, the tooth of gear has first tooth profile surface and second tooth profile surface respectively on two ends on the circumference of gear, the angle of pressure angle of first tooth profile surface with the angle of pressure angle of second tooth profile surface is not equal, for two gears that mesh with each other, the first tooth profile surface of two gears is relatively arranged, and the second tooth profile surface of two gears is relatively arranged.

[0006] In the scheme, since the displacement of the gear pump is affected by the pressure angle modulus and other parameters of the tooth profile surfaces of the gears, the first tooth profile surface and the second tooth profile surface of the gear are set to have different pressure angles in the scheme, so that the gear forms an asymmetric tooth surface, the tooth profile surfaces with the same pressure angle in the two gears that mesh with each other cooperate with each other, thereby forming different displacements when the gears rotate in different directions, meeting more use scenarios and improving the application range of the variable displacement gear pump.

[0007] Preferably, the first tooth profile and the second tooth profile are both involute tooth profiles.

[0008] In this solution, the involute tooth profile is easy to process, and the processing cost can be reduced. In addition, the use of the involute tooth profile is conducive to further improving the tolerance of the gear pump to solid particles.

[0009] Preferably, the gear is divided into a first tooth portion and a second tooth portion along the tooth width direction of the gear, the first tooth portion and the second tooth portion are both helical teeth, and the tooth line of the first tooth portion intersects the tooth line of the second tooth portion.

[0010] In this solution, by dividing the gear into a first tooth portion and a second tooth portion along the tooth width direction, both of which are helical teeth, the tooth line of the first tooth portion intersects the tooth line of the second tooth portion, that is, the first tooth portion and the second tooth portion form a certain angle to form a double helical gear. The double helical gear has a smaller width-diameter ratio than the original structure under the condition of the same flow rate of the single pair of helical gears, which is conducive to realizing the uniform load of the gear transmission, and further reduces the failure probability of the gear.

[0011] Preferably, the first tooth portion and the second tooth portion abut each other, or the first tooth portion and the second tooth portion are spaced apart along the tooth width direction of the gear, and the gear further comprises a connecting portion connected between the first tooth portion and the second tooth portion.

[0012] In this solution, the above arrangement causes the helical teeth of the first tooth portion and the second tooth portion on the same shaft to generate an automatic centering force due to the axial force, thereby reducing the gap value of the tooth width end face, and further improving the pressure and volumetric efficiency of the variable displacement gear pump. Compared with the structure in which the first tooth portion and the second tooth portion are spaced apart, the structure in which the first tooth portion and the second tooth portion abut each other can reduce the gap between the gears, further reduce the leakage amount, and thereby improve the volumetric efficiency of the gear pump.

[0013] Preferably, the length of the first tooth portion in the tooth width direction of the gear is 0.8-1.2 times the length of the second tooth portion in the tooth width direction of the gear.

[0014] In this solution, by setting the length of the first tooth portion in the tooth width direction of the gear to be 0.8-1.2 times the length of the second tooth portion in the tooth width direction of the gear, the double helical gear structure formed by the first tooth portion and the second tooth portion has a further smaller width-diameter ratio than the original structure under the condition of the same flow rate of the single pair of helical gears, thereby further realizing the uniform load of the gear transmission and reducing the failure probability of the gear.

[0015] Preferably, the length of the first tooth portion in the tooth width direction of the gear is equal to the length of the second tooth portion in the tooth width direction of the gear.

[0016] In the scheme, by making the tooth width direction proportion of the first tooth part and the second tooth part each half, the load sharing of the gear can be further improved, and the failure probability of the gear is further reduced.

[0017] Preferably, the first tooth part and the second tooth part are mutually symmetrical.

[0018] In the scheme, by making the first tooth part and the second tooth part mutually symmetrical relative to the gear tooth width direction center, the load borne by both ends of the gear when the gear pumps the liquid can be balanced, and the durability of the gear is improved.

[0019] Preferably, the driving device comprises a rotary motor and a control unit, the variable displacement gear pump further comprises a gear shaft, the gear shaft is connected with the output end of the rotary motor, and the gear is sleeved on the gear shaft; the control unit is used for changing the rotation direction of the rotary motor, so as to drive the gear shaft and the corresponding gear to rotate synchronously in the first direction or the second direction.

[0020] In the scheme, by connecting the rotary motor and the gear through the gear shaft, the gear shaft has the advantages of compact structure, light weight and stable rotation, and is suitable for application in the space-limited occasions such as the pump body. The rotation direction of the gear can be quickly changed by the control unit, so that the displacement of the gear pump is conveniently switched.

[0021] Preferably, the gear shaft and the corresponding gear are integrally formed.

[0022] In the scheme, by integrally forming the gear and the gear shaft, the gear has higher durability and can bear greater load because there is no connecting point between the gear and the gear shaft.

[0023] Preferably, the axial center lines of the two gears are parallel or intersected.

[0024] In the scheme, by making the axial center lines of the gears parallel, the whole device has the advantages of compact structure, space saving, convenient installation and maintenance. By making the axial center lines of the gears intersected, the backflow of the pumped liquid can be reduced, and the efficiency of the gear pump is improved.

[0025] The positive progress effect of the utility model lies in:

[0026] The variable displacement gear pump of the utility model, since the displacement of the gear pump is influenced by parameters such as the pressure angle modulus of the tooth profile surface of the gear meshing, therefore, the first tooth profile surface and the second tooth profile surface with different pressure angles are arranged to the gear, so that the gear forms an asymmetric tooth surface, the tooth profile surfaces with the same pressure angle in the two gears meshing with each other cooperate with each other, so that different displacements can be formed when the gears rotate in different directions, more use scenarios are met, and the application range of the variable displacement gear pump is improved. In addition, the gear adopts the asymmetric tooth profile, so that the variable displacement gear pump has low center distance sensitivity, so that the liquid containing solid particles can be pumped, and the application scenarios are widened. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 It is a structural schematic view of a straight tooth gear pump in the prior art

[0028] Figure 2 It is a structural schematic view of a helical tooth gear pump in the prior art

[0029] Figure 3 It is an assembly view of the variable displacement gear pump of the utility model embodiment

[0030] Figure 4 It is a structural schematic view of the driving gear of the utility model embodiment

[0031] Figure 5 It is a structural schematic view of the driven gear of the utility model embodiment

[0032] Figure 6 It is a schematic view of the gear meshing of the utility model embodiment

[0033] Figure 7 It is a partial schematic view of the gear of the utility model embodiment

[0034] Prior art reference signs are explained as follows:

[0035] Straight tooth gear pump 1

[0036] Straight tooth gear 101

[0037] Helical tooth gear pump 2

[0038] Single helical gear 201

[0039] Reference signs of the embodiment are explained as follows:

[0040] Variable displacement gear pump 1000

[0041] Driving gear 3

[0042] Driven gear 4

[0043] First tooth profile surface 5

[0044] Second tooth profile surface 6

[0045] First direction 7

[0046] Second direction 8

[0047] Tooth width direction 9

[0048] First tooth part 10

[0049] Second tooth part 11

[0050] Gear shaft 12

[0051] Pressure angle a 13

[0052] Pressure angle b 14 DETAILED DESCRIPTION

[0053] The utility model will be further illustrated below by way of examples, but the utility model is not limited in the scope of the examples.

[0054] As Figures 3 to 7 shown, the embodiment provides a variable displacement gear pump 1000, including driving device and two gears meshing with each other, the driving device is connected with one of the gears, for driving the gear rotates along the first direction 7 or the second direction 8, the first direction 7 and the second direction 8 are two directions opposite in the circumferential direction of the gear;The tooth of the gear has first tooth profile surface 5 and second tooth profile surface 6 at both ends in the circumferential direction of the gear respectively, the angle of the pressure angle of first tooth profile surface 5 and the angle of the pressure angle of second tooth profile surface 6 are not equal;For the two gears meshing with each other, the first tooth profile surface 5 of the two gears is oppositely arranged, and the second tooth profile surface 6 of the two gears is oppositely arranged.

[0055] Therefore, since the displacement of the gear pump is affected by the pressure angle modulus and other parameters of the meshing tooth profile surface of the gear, the present scheme sets the teeth of the gear to have first tooth profile surface 5 and second tooth profile surface 6 with different pressure angles, so that the gear forms an asymmetric tooth surface, and the tooth profile surfaces with the same pressure angle in the two gears meshing with each other cooperate with each other, thereby forming different displacements when the gear rotates in different directions, meeting more use scenarios and improving the application range of the variable displacement gear pump. In addition, the asymmetric tooth profile of the gear makes the variable displacement gear pump have lower center distance sensitivity, so that it can pump liquid containing solid particles, thereby widening its application scenarios.

[0056] In the embodiment, as Figure 3 shown, the gears meshing with each other are divided into driving gear 3 and driven gear 4, as Figure 4 and Figure 5 shown, the driving gear 3 and the driven gear 4 are the same in structure, and are both provided with first tooth profile surface 5 and second tooth profile surface 6. As Figure 7As shown in the figure, the pressure angles of the first tooth profile surface 5 and the second tooth profile surface 6 are different, and the pressure angles of the first tooth profile surface 5 and the second tooth profile surface 6 are both in the range of 0-90 degrees. Preferably, the pressure angle a13 of the first tooth profile surface 5 is 23 degrees, and the pressure angle b14 of the second tooth profile surface 6 is 14.5 degrees. The driving device is connected with the driving gear 3 to rotate the driving gear 3 in the first direction 7 or the second direction 8. Among them, as shown in the figure, Figure 3 and Figure 6 the first direction 7 is clockwise rotation along the gear circumferential direction, and the second direction 8 is counterclockwise rotation along the gear circumferential direction. The driving gear 3 drives the driven gear 4 to rotate. When the driving gear 3 rotates clockwise, the first tooth profile surface 5 of the driving gear 3 meshes with the first tooth profile surface 5 of the driven gear 4, and the displacement of the gear pump depends on the pressure angle of the first tooth profile surface 5; when the driving gear 3 rotates counterclockwise, the second tooth profile surface 6 of the driving gear 3 meshes with the second tooth profile surface 6 of the driven gear 4, and the displacement of the gear pump depends on the pressure angle of the second tooth profile surface 6.

[0057] Specifically, the first tooth profile surface 5 and the second tooth profile surface 6 are both involute tooth profiles.

[0058] In this way, the involute tooth profile is easy to process, which can reduce the processing cost. In addition, the use of involute tooth profile is conducive to further improving the resistance of the gear pump to solid particles.

[0059] In this embodiment, the involute tooth profile means that the distance from any point on the first tooth profile surface 5 or the second tooth profile surface 6 to the gear axis is equal to the sine value of the included angle between the tangent direction of the point and the gear axis multiplied by the distance from the point to the circumferential line. In other embodiments, those skilled in the art can also choose other types of tooth profiles.

[0060] Specifically, as shown in the figure, Figures 3 to 5 the gear is divided into a first tooth part 10 and a second tooth part 11 along the tooth width direction 9 of the gear, and the first tooth part 10 and the second tooth part 11 are both helical teeth, and the tooth line of the first tooth part 10 intersects with the tooth line of the second tooth part 11.

[0061] In this way, by dividing the gear into the first tooth part 10 and the second tooth part 11 which are both helical teeth along the tooth width direction 9, the tooth lines of the first tooth part 10 and the second tooth part 11 intersect, that is, the first tooth part 10 and the second tooth part 11 form a certain angle to form a double helical gear. The width-diameter ratio of the double helical gear is smaller than that of the original structure under the same flow of the single pair of helical gears, which is conducive to realizing the uniform load of the gear transmission, and further reduces the failure probability of the gear.

[0062] In the embodiment, the first tooth portion 10 and the second tooth portion 11 can abut each other. In other embodiments, the first tooth portion 10 and the second tooth portion 11 can be spaced apart along the tooth width direction 9 of the gear, and the gear comprises a connecting portion connected between the first tooth portion 10 and the second tooth portion 11. The connecting portion can be a connecting rod or a connecting shaft or the like structure, so that the first tooth portion and the second tooth portion are spliced together. The above arrangement makes the helical teeth of the first tooth portion 10 and the second tooth portion 11 on the same shaft produce an automatic centering force due to the axial force, thereby reducing the gap value of the tooth width end face, and further improving the pressure and volumetric efficiency of the variable displacement gear pump 1000. Compared with the structure in which the first tooth portion 10 and the second tooth portion 11 are spaced apart, the structure in which the first tooth portion 10 and the second tooth portion 11 abut each other can reduce the gap between the gears, further reduce the leakage amount, and thus improve the volumetric efficiency of the gear pump.

[0063] Specifically, the length of the first tooth portion 10 in the tooth width direction 9 of the gear is 0.8-1.2 times the length of the second tooth portion 11 in the tooth width direction 9 of the gear.

[0064] In this way, by setting the length of the first tooth portion 10 in the tooth width direction 9 of the gear to be 0.8-1.2 times the length of the second tooth portion 11 in the tooth width direction 9 of the gear, the double helical gear structure formed by the first tooth portion 10 and the second tooth portion 11 has a further smaller width-to-diameter ratio than the original structure under the condition of the same flow rate of the single pair of helical gears, thereby further realizing the uniform load of gear transmission and reducing the failure probability of the gear.

[0065] In the embodiment, the length of the first tooth portion 10 in the tooth width direction 9 of the gear is equal to the length of the second tooth portion 11 in the tooth width direction 9 of the gear. By making the tooth width direction 9 of the first tooth portion 10 and the second tooth portion 11 each account for half, the uniform load of the gear can be further improved, and the failure probability of the gear can be further reduced.

[0066] Specifically, the first tooth portion 10 and the second tooth portion 11 are symmetrical to each other.

[0067] In this way, by making the first tooth portion 10 and the second tooth portion 11 symmetrical to each other with respect to the center of the tooth width direction 9 of the gear, the load borne by the two ends of the gear when the gear pumps the liquid can be balanced, and the durability of the gear can be improved.

[0068] In the embodiment, the first tooth portion 10 and the second tooth portion 11 can be two single helical gears 201 spliced and assembled together to form a double helical structure, or can be integrally formed. Preferably, the first tooth portion 10 and the second tooth portion 11 are integrally formed on the same gear. With such a structure, the gap between the gears can be minimized, thereby improving the volumetric efficiency of the gear pump.

[0069] Specifically, the driving device comprises a rotary motor and a control unit, the variable displacement gear pump 1000 further comprises a toothed shaft 12 connected with the output end of the rotary motor, wherein a gear is sleeved on the toothed shaft 12; the control unit is used for changing the rotation direction of the rotary motor to drive the toothed shaft 12 and the corresponding gear to rotate synchronously in the first direction 7 or the second direction 8.

[0070] In this way, the rotary motor and the gear are connected through the toothed shaft 12, and the gear shaft has the advantages of compact structure, light weight and stable rotation, and is suitable for application in a space-limited occasion such as a pump body. The rotation direction of the gear can be quickly changed by changing the rotation direction of the rotary motor through the control unit, so that the displacement of the gear pump can be switched.

[0071] In the embodiment, the rotary motor is used to provide power for the rotation of the toothed shaft 12. The control unit is electrically connected with the rotary motor to facilitate switching the direction of the output of the motor.

[0072] Specifically, as shown in Figures 3 to 5 the toothed shaft 12 is integrally formed with the corresponding gear.

[0073] In this way, the gear and the toothed shaft 12 are integrally formed, and there is no connection point between the gear and the toothed shaft 12, so that the gear has higher durability and can bear larger load.

[0074] In the embodiment, the gear is sleeved on the toothed shaft 12, and the gear can be detachably connected with the toothed shaft 12 or fixedly connected with the toothed shaft 12 by welding or the like. Preferably, the gear is integrally formed with the toothed shaft 12. By adopting such a structure, the strength of the gear and the toothed shaft 12 can be maximized, thereby improving the durability of the gear pump.

[0075] Specifically, the axial center lines of the two gears are parallel or intersected.

[0076] In this way, by making the axial center lines of the gears parallel, the whole device can have a compact structure, save space and be convenient for installation and maintenance. By making the axial center lines of the gears intersected, the backflow of the pumped liquid can be reduced, thereby helping to improve the efficiency of the gear pump.

[0077] In the embodiment, the axial center line of the gear refers to the center line in the axial direction of the gear. The axial center lines of the driving gear 3 and the driven gear 4 are parallel, i.e. parallel-axle gears, or the axial center lines of the driving gear 3 and the driven gear 4 are intersected, i.e. intersected-axle gears.

[0078] The variable displacement gear pump 1000 adopting the above structure has the following advantages:

[0079] 1. The gear pump can cope with higher pressure performance, and the pressure differential of the gear pump is greater than 20 Mpa, and the pressure at the pressure-bearing end is greater than 35 Mpa;

[0080] 2. The gear pump has two separate displacement;

[0081] 3. The gear pump does not need to process separately unloading groove;

[0082] 4. The gear pump can accept a certain degree of solid particles in the liquid, the viscosity range of the liquid end is 1-4000000mpas;

[0083] 5. When the gear pump should respond to large flow conditions, the gear tooth width ratio can be reduced as much as possible to reduce the risk of local failure of the gear;

[0084] 6. The gear pump speed can reach 30000rpm, under the premise of a certain unilateral displacement, the pump flow per unit time increases by about 5-10 times;

[0085] 7. The gear pump has low sensitivity to spiral angle and center distance, and the gear does not need to be run separately to achieve ideal running state;

[0086] 8. The gear pump can correct the gear noise and vibration caused by load, thermal deformation, assembly and machining errors by modification, so that the gear pump has the same low noise and low vibration as the single helical gear pump.

[0087] Although the specific embodiments of the present application are described above, those skilled in the art should understand that this is only an example, the protection scope of the present application is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principles and essence of the present application, but these changes and modifications all fall within the protection scope of the present application.

Claims

1. A variable-displacement gear pump comprising a driving device and two gears which mesh with each other, characterized in that, The driving device is connected with one of the gears, and is used to drive the gear to rotate in a first direction or a second direction, the first direction and the second direction being two opposite directions in the circumferential direction of the gear; The gear has a first tooth profile surface and a second tooth profile surface at two ends in the circumferential direction of the gear, and the pressure angle of the first tooth profile surface and the pressure angle of the second tooth profile surface are not equal; for the two gears in mutual engagement, the first tooth profile surfaces of the two gears are oppositely arranged, and the second tooth profile surfaces of the two gears are oppositely arranged.

2. The variable-displacement gear pump of claim 1, wherein The first tooth profile surface and the second tooth profile surface are both involute tooth profiles.

3. The variable-displacement gear pump of claim 1, wherein The gear is divided into a first tooth part and a second tooth part in the tooth width direction of the gear, the first tooth part and the second tooth part are both helical teeth, and the tooth line of the first tooth part intersects the tooth line of the second tooth part.

4. A variable-displacement gear pump as set forth in claim 3, characterized in that, The first tooth part and the second tooth part abut against each other. Alternatively, the first tooth part and the second tooth part are arranged in a spaced manner in the tooth width direction of the gear, and the gear further comprises a connecting part connected between the first tooth part and the second tooth part.

5. The variable-displacement gear pump of claim 3, wherein, The length of the first tooth part in the tooth width direction of the gear is 0.8-1.2 times the length of the second tooth part in the tooth width direction of the gear.

6. A variable-displacement gear pump as set forth in claim 5, characterized in that, The length of the first tooth part in the tooth width direction of the gear is equal to the length of the second tooth part in the tooth width direction of the gear.

7. A variable-displacement gear pump as set forth in claim 6, characterized in that, The first tooth part and the second tooth part are symmetrical to each other.

8. The variable-displacement gear pump of claim 1, wherein, The driving device comprises a rotary motor and a control unit, and the variable displacement gear pump further comprises a gear shaft connected with the output end of the rotary motor, and one of the gears is sleeved on the gear shaft; The control unit is used to change the rotation direction of the rotary motor to drive the gear shaft and the corresponding gear to rotate synchronously in a first direction or a second direction.

9. A variable-displacement gear pump as set forth in claim 8, characterized in that, The gear shaft and the corresponding gear are integrally formed.

10. The variable-displacement gear pump of claim 1, wherein, The axial center lines of the two gears are parallel or intersected.

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