JP-7857170-B2 - Internal gear pump

JP7857170B2JP 7857170 B2JP7857170 B2JP 7857170B2JP-7857170-B2

Inventors

石夏氷
大西孝明
竹田博昭

Assignees

住友精密工業株式会社

Dates

Publication Date: 20260512
Application Date: 20220616

Claims (5)

A pinion gear having external teeth, A ring gear having internal teeth that mesh with the external teeth, A housing having an intake port and a discharge port, and rotatably housing the pinion gear and the ring gear, The crescent is located at a point where the meshing of the pinion gear and the ring gear separates, and has a first arc-shaped wall in contact with the external teeth and a second arc-shaped wall in contact with the internal teeth. The first and second arc-shaped walls are both fixed walls that do not move toward the external and internal teeth. Of the region on the pinion gear side and the region on the ring gear side, the pressure transmission oil passage extending from the discharge port is formed within the housing only in the region on the ring gear side. The pressure transmission oil passage is an internal gear pump that connects the discharge port and the space between the teeth of the ring gear.
In the internal gear pump according to claim 1, The housing has a sliding surface on which the outer circumferential surface of the ring gear slides, The system includes a high-pressure oil supply unit that supplies high-pressure hydraulic fluid between the outer circumferential surface and the sliding surface through an inlet opening that opens to the sliding surface, The inlet is located on the opposite side of the crescent from the ring gear in the internal gear pump.
In the internal gear pump according to claim 1 or 2, The housing has a first support surface and a second support surface that support two sides of the ring gear that are perpendicular to the rotation axis of the ring gear, respectively. The discharge ports are formed on the first support surface and the second support surface, The pressure transmission oil passage is formed to be recessed from the first support surface, the second support surface, or the first support surface and the second support surface. An internal gear pump in which the pressure transmission oil passage overlaps with the space between the teeth of the ring gear when viewed in the direction of the rotating shaft.
In the internal gear pump according to claim 1 or 2, The pressure transmission oil passage is formed to recess from the second circular arc wall of the crescent, in an internal gear pump.
In the internal gear pump according to claim 1 or 2, An internal gear pump in which the tip of the pressure transmission oil passage is located within a range of an angle θ1 or greater from the edge of the discharge port, corresponding to the tooth width of the ring gear, and an angle θ2 or less from the midpoint of the crescent extending from the discharge port to the suction port, with respect to the rotation axis of the ring gear.

Description

The technology disclosed herein relates to an internal gear pump. Patent Document 1 describes an internal gear pump (1). This internal gear pump (1) has a separating member (7) (a so-called crescent). The teeth of the internal gear (2) and the teeth of the pinion (3) each contact the separating member (7). The separating member (7) has an inner portion (13), an outer portion (14), and a spring (16). The spring (16) presses the inner portion (13) against the teeth of the pinion (3) and the outer portion (14) against the teeth of the internal gear (2). The separating member (7) has a movable structure. The movable separating member (7) suppresses leakage flow within the internal gear pump (1) and improves pump efficiency. The separating member (7) also has an intermediate space (17) between its inner portion (13) and outer portion (14). The intermediate space (17) communicates with the pressurized region (9) of the internal gear pump (1). The inner portion (13) and outer portion (14) have through-holes (19). The through-holes (19) penetrate radially through both the inner portion (13) and the outer portion (14), connecting the intermediate portion (17) to the space between the teeth of the pinion (3) and the internal gear (2). When the internal gear pump (1) is operating, the intermediate space (17) is at the same pressure as the pressurized region (9), thus increasing the pressure in the space between the teeth of the pinion (3) and the internal gear (2) through the through-holes (19). This high pressure in the space between the teeth suppresses rapid pressure changes at the pump discharge section, thereby reducing noise from the internal gear pump (1). Patent No. 6297277 Figure 1 is an exploded view of an internal gear pump.Figure 2 is a cross-sectional view of an internal gear pump.Figure 3 illustrates a pressure transmission oil passage.Figure 4 shows a modified example of a pressure transmission oil passage.Figure 5 shows a modified example of a pressure transmission oil passage. The following describes an embodiment of the internal gear pump with reference to the drawings. The internal gear pump described here is illustrative. (Overall structure of the internal gear pump) Figures 1 and 2 illustrate an internal gear pump 1. The internal gear pump 1 comprises a shaft 2, a pinion gear 3, a ring gear 4, a gear housing 5, and a front cover 6. The gear housing 5 and the front cover 6 constitute the housing 10 of the internal gear pump 1. Figure 1 is an exploded view with the front cover 6 removed from the gear housing 5. Shaft 2 extends in the left-right direction in Figure 2. Shaft 2 consists of a first shaft 21 and a second shaft 22. The first shaft 21 and the second shaft 22 are coupled coaxially and rotate together. The second shaft 22 protrudes from the housing 10 and is connected to a prime mover (not shown). The prime mover is, for example, an electric motor. The pinion gear 3 is integrally formed at the intermediate position of the first shaft 21. The pinion gear 3 and the shaft 2 are coaxial. The pinion gear 3 rotates together with the shaft 2. The pinion gear 3 has external teeth 31. The ring gear 4 meshes with the pinion gear 3. The ring gear 4 is positioned eccentrically with respect to the shaft 2. In Figure 1, C1 is the axis of rotation of the pinion gear 3, and C2 is the axis of rotation of the ring gear 4. Internal teeth 41 are formed on the inner circumferential surface of the ring gear 4. In the right-hand diagram of Figure 1, in the area on the right side of the paper, a portion of the external teeth 31 of the pinion gear 3 meshes with a portion of the internal teeth 41 of the ring gear 4. The gear housing 5 accommodates the pinion gear 3 and the ring gear 4. An inner bore 53 is formed in the gear housing 5. The end of the first shaft 21 is located within the inner bore 53. The pinion gear 3 and ring gear 4 are rotatably housed in the gear housing 5. The gear housing 5 has a sliding surface 51 on which the outer circumferential surface 42 of the ring gear 4 slides. The outer circumferential surface 42 of the ring gear 4 has a circular cross-section. The sliding surface 51 of the gear housing 5 also has a circular cross-section. The sliding surface 51 is eccentric with respect to the shaft 2. The gear housing 5 has a first support surface 52 perpendicular to the sliding surface 51. The sliding surface 51 and the first support surface 52 form a space 50 that houses the pinion gear 3 and the ring gear 4. This space 50 is open to the left side of the paper in Figure 2. The first side surface 32 of the pinion gear 3 and the first side surface 43 of the ring gear 4 are supported by and slide on the first support surface 52 of the gear housing 5. The first side surface 32 of the pinion gear 3 is the surface perpendicular to the rotation axis C1 of the pinion gear 3, and is the right side surface in Figure 2. The first side surface 43 of the ring gear 4 is the surface perpendicular to the rotation