JP2020029826A - Liquid pump - Google Patents

Abstract

To provide a liquid pump capable of switching an operation by two pump rotors and an operation by only one pump rotor with a simple constitution.SOLUTION: An oil pump 1 includes a shaft 2, a first pump rotor 3 and a second pump rotor 4 arranged in parallel with each other in an axial direction of the shaft 2 and fixed to the shaft 2, and a housing 5 rotatably supporting the shaft 2 and housing the first pump rotor 3 and the second pump rotor 4. The shaft 2 has a first shaft portion 8 fixed to the first pump rotor 3, and a second shaft portion 9 fixed to the second pump rotor 4 in a manner of being kept into contact with and separated from the first shaft portion 8. The first shaft portion 8 and the second shaft portion 9 are connected when a discharge pressure of the first pump rotor 3 is a prescribed value or less, and the first shaft portion 8 and the second shaft portion 9 are separated when the discharge pressure of the first pump rotor 3 is higher than the prescribed value.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a liquid pump.

  As a conventional liquid pump, for example, an oil pump described in Patent Document 1 is known. The oil pump described in Patent Literature 1 includes a first pump and a second pump that are driven by a drive gear and are removably connected via a clutch. When the engine is at a low speed and does not require much oil pressure and oil amount, the clutch is disengaged to cut off oil supply to the second pump and to allow oil to flow only to the first pump. When the engine rotates at a high speed and a hydraulic pressure and an oil amount are required, engaging the clutch allows oil to be sent to the second pump, and allows the oil to flow through the first and second pumps.

JP-B-59-150991

  However, in the above-mentioned conventional technology, the oil pump to the second pump is allowed or cut off by controlling the clutch and the solenoid valve based on a signal from the CPU, so that the configuration of the oil pump must be complicated. Absent.

  An object of the present invention is to provide a liquid pump that can switch between operation by two pump rotors and operation by only one pump rotor with a simple configuration.

  A liquid pump according to one embodiment of the present invention includes a shaft that is rotationally driven via a drive system, a first pump rotor and a second pump rotor that are arranged side by side in the axial direction of the shaft and fixed to the shaft. And a housing for rotatably supporting the shaft and accommodating the first pump rotor and the second pump rotor, wherein the shaft is connected to a drive system and fixed to the first pump rotor. And a second shaft portion fixed to the second pump rotor and separable from the first shaft portion. When the discharge pressure of the first pump rotor is equal to or lower than a predetermined value, the first shaft portion When the discharge pressure of the first pump rotor is higher than a predetermined value, the first shaft portion and the second shaft portion are separated from each other.

  In such a liquid pump, the first shaft portion fixed to the first pump rotor and the second shaft portion fixed to the second pump rotor can be separated. When the discharge pressure of the first pump rotor is equal to or lower than a predetermined value, the first shaft portion and the second shaft portion are connected. Therefore, the normal operation of discharging the liquid from the first pump rotor and the second pump rotor is performed. When the discharge pressure of the first pump rotor is higher than a predetermined value, the first shaft portion and the second shaft portion are separated. Therefore, since the liquid is discharged only from the first pump rotor, it is possible to prevent the second pump rotor from performing useless work. As described above, with the simple configuration of coupling or separating the first shaft portion and the second shaft portion, the operation by the first pump rotor and the second pump rotor and the operation by only the first pump rotor can be switched.

  The liquid pump further includes an elastic member that urges the first shaft portion and the second shaft portion in a direction in which the first shaft portion and the second shaft portion are coupled to each other. The first shaft portion and the second shaft portion may be separated when the portion and the second shaft portion are connected and the discharge pressure of the first pump rotor is higher than the urging force of the elastic member. By using the elastic member as described above, when the discharge pressure of the first pump rotor is equal to or less than a predetermined value, the first shaft portion and the second shaft portion are connected to each other, and the discharge pressure of the first pump rotor is set to a predetermined value. When it is higher than the value, the operation of separating the first shaft portion and the second shaft portion can be realized by a simple mechanism.

  The elastic member may be arranged on the opposite side of the first shaft portion with respect to the second shaft portion. Since the drive system is connected to the first shaft portion, if the elastic member is disposed on the opposite side of the second shaft portion with respect to the first shaft portion, the size of the liquid pump may increase in the axial direction of the shaft. is there. By arranging the elastic member on the opposite side of the first shaft portion with respect to the second shaft portion, the elastic member can be arranged with good space efficiency. This prevents the liquid pump from increasing in size in the axial direction of the shaft.

  The housing has a partition wall disposed between the first pump rotor and the second pump rotor. The partition wall has liquid chambers for the first pump rotor and the second pump rotor, a first shaft portion, and a second shaft portion. A leak passage communicating the space between the two shaft portions may be provided. In such a configuration, the liquid discharged from the first pump rotor passes through the leak passage and is guided to the space between the first shaft portion and the second shaft portion. For this reason, the discharge pressure of the first pump rotor is given to the space between the first shaft portion and the second shaft portion. Accordingly, the first shaft portion and the second shaft portion are easily coupled or separated according to the magnitude relationship between the discharge pressure of the first pump rotor and the urging force of the elastic member.

  One of the first shaft portion and the second shaft portion may be provided with a convex portion, and the other of the first shaft portion and the second shaft portion may be provided with a concave portion fitted with the convex portion. . In this case, coupling and separation between the first shaft portion and the second shaft portion can be realized with a simple structure.

  The protrusion and the recess may have a structure for preventing relative rotation between the first shaft portion and the second shaft portion. In this case, when the first shaft portion and the second shaft portion are coupled to each other, the first shaft portion and the second shaft portion are prevented from rotating relative to each other.

  The capacity of the first pump rotor may be larger than the capacity of the second pump rotor. In this case, since the first shaft portion and the second shaft portion are separated from each other, the discharge pressure of the first pump rotor is ensured even when the liquid is discharged only from the first pump rotor.

  According to the present invention, operation with two pump rotors and operation with only one pump rotor can be switched with a simple configuration.

FIG. 1 is a sectional view showing an oil pump as a liquid pump according to one embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II of FIG. FIG. 3A is a cross-sectional view illustrating a state where the first shaft portion and the second shaft portion illustrated in FIG. 1 are combined, and FIG. 3B is a cross-sectional view illustrating the first shaft portion illustrated in FIG. It is sectional drawing which shows the state which the part and the 2nd shaft part were isolate | separated. FIG. 4 is a cross-sectional view showing the shapes of the convex portions and the concave portions shown in FIG. FIG. 5 is a conceptual diagram showing an operation state of an oil pump as a comparative example. FIG. 6A is a conceptual diagram illustrating an operating state of the oil pump at a normal time, and FIG. 6B is a conceptual diagram illustrating an operating state of the oil pump at an excessive pressure.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or equivalent elements have the same reference characters allotted, and overlapping description will be omitted.

  FIG. 1 is a sectional view showing an oil pump as a liquid pump according to one embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II of FIG. 1 and 2, an oil pump 1 according to the present embodiment is a liquid pump mounted on a vehicle and for pumping engine oil for lubricating an engine. The oil pump 1 is, for example, a two-rotor trochoid pump.

  The oil pump 1 is rotatable with the shaft 2, the first pump rotor 3 and the second pump rotor 4 which are arranged side by side in the axial direction of the shaft 2, and are fixed to the outer peripheral surface of the shaft 2. And a housing 5 for accommodating the first pump rotor 3 and the second pump rotor 4.

  The shaft 2 is rotationally driven via a drive system 6. The drive system 6 has an oil pump gear 7 fixed to the outer peripheral surface of the shaft 2. A crank gear (not shown) meshes with the oil pump gear 7 via an idler gear (not shown). When a crankshaft (not shown) rotates, the rotation is transmitted to an oil pump gear 7 via a crank gear and an idler gear, and the shaft 2 rotates.

  The shaft 2 has a first shaft portion 8 and a second shaft portion 9 arranged on the rear end side of the first shaft portion 8. The oil pump gear 7 is connected to a front end of the first shaft 8. The first shaft portion 8 is fixed to the first pump rotor 3. The second shaft portion 9 is fixed to the second pump rotor 4. The second shaft section 9 is separable from the first shaft section 8.

  As shown in FIG. 3, a convex portion 10 is provided on the front end surface of the second shaft portion 9. The rear end surface of the first shaft portion 8 is provided with a concave portion 11 that fits with the convex portion 10. The convex portion 10 and the concave portion 11 have a structure for preventing relative rotation between the first shaft portion 8 and the second shaft portion 9.

  Specifically, as shown in FIG. 4, the protrusion 10 has a columnar portion 12 and a pair of protrusions 13 protruding from the outer peripheral surface of the columnar portion 12. The pair of projecting portions 13 are arranged so as to sandwich the columnar portion 12. The concave portion 11 has a cross-sectional shape corresponding to the convex portion 10. Specifically, the concave portion 11 has a column fitting portion 14 that fits with the columnar portion 12, and a pair of projection fitting portions 15 that fit with the respective projecting portions 13. FIG. 4 is a cross-sectional view taken perpendicularly to the axial direction of the shaft 2.

  The first pump rotor 3 has an inner rotor 16 fixed to the outer peripheral surface of the rear end portion of the first shaft portion 8, and an outer rotor 17 arranged radially outside the inner rotor 16. The outer peripheral portion of the inner rotor 16 is provided with a plurality of outer peripheral teeth 16a. The shape of the outer peripheral teeth 16a is a shape similar to a trochoid curve or a substantially trochoid curve. The inner peripheral portion of the outer rotor 17 is provided with a plurality of inner peripheral teeth 17a. The space between the inner rotor 16 and the outer rotor 17 forms a hydraulic chamber 18 (liquid chamber).

  The axis of the first shaft portion 8 and the axis of the inner rotor 16 are eccentric with respect to the axis of the outer rotor 17. A part of the plurality of outer teeth 16a meshes with a part of the plurality of inner teeth 17a. Therefore, when the inner rotor 16 rotates due to the rotation of the first shaft portion 8, the outer rotor 17 rotates.

  The second pump rotor 4 has an inner rotor 19 fixed to the outer peripheral surface of the second shaft portion 9 and an outer rotor 20 disposed radially outside the inner rotor 19. A plurality of outer teeth (not shown) are provided on the outer periphery of the inner rotor 19. The shape of the outer peripheral teeth is a shape similar to a trochoid curve or a substantially trochoid curve. A plurality of inner peripheral teeth (not shown) are provided on an inner peripheral portion of the outer rotor 20. The space between the inner rotor 19 and the outer rotor 20 constitutes a hydraulic chamber 21 (liquid chamber).

  The axes of the second shaft portion 9 and the inner rotor 19 are eccentric with respect to the axis of the outer rotor 20. A part of the plurality of outer teeth meshes with a part of the plurality of inner teeth. Therefore, when the inner rotor 19 rotates due to the rotation of the second shaft portion 9, the outer rotor 20 rotates.

  The outer diameter of the outer rotor 17 is equal to the outer diameter of the outer rotor 20. The outer diameter of the inner rotor 16 is larger than the outer diameter of the inner rotor 19. Thereby, the capacity of the first pump rotor 3 is larger than the capacity of the second pump rotor 4.

  The housing 5 houses the first pump rotor 3 and the second pump rotor 4, and is disposed between the body 22 and the oil pump gear 7, and rotatably supports the second shaft portion 9, The cover 23 rotatably supports the first shaft portion 8 and is disposed between the first pump rotor 3 and the second pump rotor 4, and rotatably supports the first shaft portion 8 and the second shaft portion 9. And a partition wall 24. The cover 23 is fastened to the front end surface of the body 22 with bolts 25. The partition wall 24 is fixed to the inner wall surface of the body 22.

  The body 22 is provided with a suction port 26 for sucking engine oil and a discharge port 27 for discharging engine oil. The partition wall 24 has a suction section 28 communicating with the hydraulic chamber 18 of the first pump rotor 3, a suction section 29 communicating with the hydraulic chamber 21 of the second pump rotor 4, and a hydraulic chamber of the first pump rotor 3. A discharge section 30 communicated with 18 and a discharge section 31 communicated with the hydraulic chamber 21 of the second pump rotor 4 are provided. The discharge units 30 and 31 are arranged at positions away from the suction units 28 and 29.

  The suction port 26 and the suction portions 28 and 29 communicate with each other via a passage 32 provided in the body 22 and the partition wall 24. The discharge port 27 and the discharge units 30 and 31 communicate with each other through a passage 33 provided in the partition wall 24. Further, the partition wall 24 is provided with a leak passage 35 that allows the discharge units 30 and 31 to communicate with a space 34 (see FIG. 3B) between the first shaft unit 8 and the second shaft unit 9. ing.

  A shaft spring 36 that urges the second shaft portion 9 toward the first shaft portion 8 is disposed behind the second shaft portion 9. That is, the shaft spring 36 is disposed on the opposite side of the first shaft portion 8 with respect to the second shaft portion 9. The shaft spring 36 is an elastic member that urges the first shaft portion 8 and the second shaft portion 9 in a direction in which they are joined. One end of the shaft spring 36 contacts the second shaft portion 9, and the other end of the shaft spring 36 contacts the body 22.

  In the oil pump 1 as described above, the engine oil in the hydraulic chamber 18 of the first pump rotor 3 passes through the discharge portion 30 and the leak passage 35 and is provided in the space between the first shaft portion 8 and the second shaft portion 9. 34 leaks. Therefore, the discharge pressure of the first pump rotor 3 is given to the space 34 between the first shaft portion 8 and the second shaft portion 9.

  When the discharge pressure of the first pump rotor 3 is equal to or lower than the urging force (predetermined value) of the shaft spring 36, as shown in FIG. The two shaft portions 9 are connected. At this time, the convex portion 10 of the second shaft portion 9 and the concave portion 11 of the first shaft portion 8 are fitted. Therefore, since the first shaft portion 8 and the second shaft portion 9 rotate together, the first pump rotor 3 and the second pump rotor 4 are driven to rotate together. Therefore, the engine oil from the first pump rotor 3 and the second pump rotor 4 is discharged from the discharge port 27.

  On the other hand, when the discharge pressure of the first pump rotor 3 is higher than the urging force (predetermined value) of the shaft spring 36, as shown in FIG. The shaft portion 8 and the second shaft portion 9 are separated. Therefore, only the first shaft portion 8 rotates and the second shaft portion 9 does not rotate, so that only the first pump rotor 3 is driven to rotate, and the second pump rotor 4 is not driven to rotate. Therefore, only the engine oil from the first pump rotor 3 is discharged from the discharge port 27. In FIG. 3B, the state where the first shaft portion 8 and the second shaft portion 9 are separated is exaggerated for convenience.

  FIG. 5 is a conceptual diagram showing an operation state of an oil pump as a comparative example. In FIG. 5, an oil pump 50 of the present comparative example includes a first pump rotor 3 and a second pump rotor 4 fixed to one shaft 51. A relief valve 52 is connected to a discharge port of the oil pump 50. When the discharge pressure of the oil pump 50 is excessive, the relief valve 52 releases the engine oil. Therefore, the first pump rotor 3 and the second pump rotor 4 are performing useless work.

  In the present embodiment, at normal times when the discharge pressure of the oil pump 1 is not excessive, the urging force of the shaft spring 36 overcomes the discharge pressure of the oil pump 1 as shown in FIG. And the second shaft portion 9 are connected. Thereby, the engine oil from the first pump rotor 3 and the second pump rotor 4 is discharged from the discharge port 27 as described above.

  On the other hand, when the discharge pressure of the oil pump 1 is excessive, as shown in FIG. 6B, the discharge pressure of the oil pump 1 overcomes the urging force of the shaft spring 36, so that the first shaft portion 8 and the second shaft portion 9 is cut off. As a result, only the engine oil from the first pump rotor 3 is discharged from the discharge port 27 as described above.

  As described above, according to the present embodiment, the first shaft portion 8 fixed to the first pump rotor 3 and the second shaft portion 9 fixed to the second pump rotor 4 can be separated. When the discharge pressure of the first pump rotor 3 is equal to or lower than a predetermined value, the first shaft portion 8 and the second shaft portion 9 are connected. Therefore, the normal operation of discharging the engine oil from the first pump rotor 3 and the second pump rotor 4 is performed. When the discharge pressure of the first pump rotor 3 is higher than a predetermined value, the first shaft portion 8 and the second shaft portion 9 are separated. Therefore, since engine oil is discharged only from the first pump rotor 3, it is possible to prevent the second pump rotor 4 from performing useless work. As described above, with the simple configuration of coupling or separating the first shaft portion 8 and the second shaft portion 9, the operation by the first pump rotor 3 and the second pump rotor 4 and the operation by only the first pump rotor 3 can be performed. Can switch.

  Further, fuel efficiency can be improved by reducing the work amount of the second pump rotor 4. Further, since the relief valve as in the comparative example is not required, the number of parts can be reduced, and the cost and the mass can be reduced.

  Further, in the present embodiment, the shaft spring 36 that urges the first shaft portion 8 and the second shaft portion 9 in the direction of coupling is provided, and the discharge pressure of the first pump rotor 3 is reduced by the shaft spring 36. When the pressure is equal to or less than the biasing force, the first shaft portion 8 and the second shaft portion 9 are connected. When the discharge pressure of the first pump rotor 3 is higher than the biasing force of the shaft spring 36, the first shaft portion 8 and the second shaft portion 9 are connected. The second shaft portion 9 is separated. By using the shaft spring 36 in this manner, when the discharge pressure of the first pump rotor 3 is equal to or lower than a predetermined value, the first shaft portion 8 and the second shaft portion 9 are connected, and the first pump rotor 3 When the discharge pressure is higher than a predetermined value, the operation of separating the first shaft portion 8 and the second shaft portion 9 can be realized by a simple mechanism.

  In this embodiment, since the shaft spring 36 is arranged on the opposite side of the first shaft portion 8 with respect to the second shaft portion 9, the second shaft shaft 36 is connected to the first shaft portion 8 to which the drive system 6 is connected. Compared to the case where the shaft spring 36 is arranged on the opposite side of the portion 9, the shaft spring 36 can be arranged with a better space efficiency. This prevents the oil pump 1 from increasing in size in the axial direction of the shaft 2.

  Further, in the present embodiment, the partition wall 24 disposed between the first pump rotor 3 and the second pump rotor 4 includes the hydraulic chamber 18 of the first pump rotor 3 and the hydraulic chamber 21 of the second pump rotor 4. A leak passage 35 is provided to allow communication between the first shaft portion 8 and the space 34 between the second shaft portion 9. In such a configuration, the engine oil discharged from the hydraulic chamber 18 of the first pump rotor 3 passes through the leak passage 35 and is guided to the space 34 between the first shaft portion 8 and the second shaft portion 9. For this reason, the discharge pressure of the first pump rotor 3 is given to the space 34 between the first shaft portion 8 and the second shaft portion 9. Thus, the first shaft portion 8 and the second shaft portion 9 are easily coupled or separated according to the magnitude relationship between the discharge pressure of the first pump rotor 3 and the urging force of the shaft spring 36.

  Further, in the present embodiment, the convex portion 10 is provided on the second shaft portion 9, and the concave portion 11 to be fitted with the convex portion 10 is provided on the first shaft portion 8. Coupling and separation with the shaft portion 9 can be realized with a simple structure.

  Further, in the present embodiment, since the convex portion 10 and the concave portion 11 have a structure for preventing the relative rotation between the first shaft portion 8 and the second shaft portion 9, the first shaft portion 8 and the second shaft portion 9 have the same structure. In a state where the portion 9 is connected, the first shaft portion 8 and the second shaft portion 9 are prevented from rotating relative to each other.

  Further, in the present embodiment, since the capacity of the first pump rotor 3 is larger than the capacity of the second pump rotor 4, the first shaft section 8 and the second shaft section 9 are separated, so that the first pump rotor 3 is separated. The discharge pressure of the first pump rotor 3 is secured even when the engine oil is discharged only from the third pump rotor 3.

  Note that the present invention is not limited to the above embodiment. For example, in the above embodiment, the convex portion 10 has the columnar portion 12 and the pair of projection portions 13, and the concave portion 11 has the columnar fitting portion 14 and the pair of projection fitting portions 15. And the concave portion 11 has a structure for preventing the relative rotation between the first shaft portion 8 and the second shaft portion 9, and the structure for preventing the relative rotation between the first shaft portion 8 and the second shaft portion 9. Is not particularly limited to that form. For example, the shape of the convex portions 10 and the concave portions 11 may be a rectangular parallelepiped shape, or the number of the convex portions 10 and the concave portions 11 may be plural.

  In the above embodiment, the convex portion 10 is provided on the second shaft portion 9 and the concave portion 11 is provided on the first shaft portion 8. However, the present invention is not particularly limited to this, and the convex portion 10 may be provided on the first shaft portion 8. The portion 10 may be provided, and the concave portion 11 may be provided in the second shaft portion 9.

  Further, in the above embodiment, the shaft spring 36 is disposed on the opposite side of the first shaft portion 8 with respect to the second shaft portion 9; however, the present invention is not particularly limited to this, and if there is no obstacle in space, The shaft spring 36 may be arranged on the opposite side of the first shaft portion 8 from the second shaft portion 9.

  Further, in the above embodiment, the capacity of the first pump rotor 3 is larger than the capacity of the second pump rotor 4. However, the present invention is not particularly limited to this, and the capacity of the first pump rotor 3 is 4, or the capacity of the first pump rotor 3 may be equal to the capacity of the second pump rotor 4.

  Furthermore, in the above embodiment, the oil pump 1 is a trochoid pump, but the present invention is also applicable to an internal gear pump other than the trochoid pump.

  Further, the above embodiment is the oil pump 1 for pumping the engine oil, but the present invention is also applicable to an oil pump for pumping oil other than the engine oil. Further, the present invention is not particularly limited to an oil pump, but can be applied to any liquid pump that pumps liquid.

  DESCRIPTION OF SYMBOLS 1 ... Oil pump (liquid pump), 2 ... Shaft, 3 ... 1st pump rotor, 4 ... 2nd pump rotor, 5 ... Housing, 6 ... Drive system, 8 ... 1st shaft part, 9 ... 2nd shaft part, Reference numeral 10: convex portion, 11: concave portion, 18: hydraulic chamber (liquid chamber), 21: hydraulic chamber (liquid chamber), 24: partition wall, 34: space, 35: leak passage, 36: shaft spring (elastic member).

Claims (7)

A shaft that is rotationally driven through a drive system,
A first pump rotor and a second pump rotor arranged in the axial direction of the shaft and fixed to the shaft;
A housing that rotatably supports the shaft and houses the first pump rotor and the second pump rotor;
The shaft is connected to the driving system, and a second shaft fixed to the first pump rotor and a second shaft fixed to the second pump rotor and separable from the first shaft. And a shaft portion,
When the discharge pressure of the first pump rotor is equal to or lower than a predetermined value, the first shaft portion and the second shaft portion are connected, and when the discharge pressure of the first pump rotor is higher than the predetermined value. A liquid pump in which the first shaft portion and the second shaft portion are separated. An elastic member that urges the first shaft portion and the second shaft portion in a direction in which the first shaft portion and the second shaft portion are coupled to each other;
When the discharge pressure of the first pump rotor is equal to or lower than the urging force of the elastic member, the first shaft portion and the second shaft portion are connected, and the discharge pressure of the first pump rotor is reduced by the elastic member. The liquid pump according to claim 1, wherein when the force is higher than the urging force, the first shaft portion and the second shaft portion are separated.   The liquid pump according to claim 2, wherein the elastic member is disposed on a side opposite to the first shaft portion with respect to the second shaft portion. The housing has a partition wall disposed between the first pump rotor and the second pump rotor,
The partition wall is provided with a leak passage that communicates a liquid chamber of the first pump rotor and the second pump rotor with a space between the first shaft portion and the second shaft portion. Item 4. The liquid pump according to item 2 or 3. A convex portion is provided on one of the first shaft portion and the second shaft portion,
The liquid pump according to any one of claims 1 to 4, wherein the other of the first shaft portion and the second shaft portion is provided with a concave portion that fits with the convex portion.   6. The liquid pump according to claim 5, wherein the convex portion and the concave portion have a structure that prevents relative rotation between the first shaft portion and the second shaft portion. 7.   The liquid pump according to claim 1, wherein a capacity of the first pump rotor is larger than a capacity of the second pump rotor.

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