JP2015004362A - Internal gear pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accommodate a check valve in a pump outlet in a cover of an internal gear pump while saving a space, in a skid control type hydraulic vehicle brake system.SOLUTION: An internal gear pump includes a pinion 9 eccentrically positioned in a ring gear 11 and engaged with the ring gear, and a cover 4 for sealing an installation space 28. A pump outlet 29 of the internal gear pump lis led through the cover, and includes a check valve 38 to allow a liquid from the internal gear pump to flow, and to inhibit backflow of the liquid from the pump outlet to the internal gear pump. A filter 31 is disposed in a pressure field 20 of the cover 4.

Description

  The present invention relates to an internal gear pump having the features set forth in the preamble of claim 1. This is particularly expected as a hydro pump instead of the piston pump normally used in skid controlled vehicle brake systems. Such hydropumps are often called return pumps, although this is not always the case. In the skid-controlled hydraulic vehicle brake system, the pump outlet, that is, the pressure side of the hydro pump is connected to a brake line that leads from the master brake cylinder to the wheel brake cylinder. The brake pressure generated by the operation of the master brake cylinder dominates the pump outlet.

  The internal gear pump includes a ring gear, that is, a gear with internal teeth, and a pinion that is arranged eccentrically in the ring gear and meshes with the ring gear, that is, a gear with external teeth. These gears are called pinion and ring gear, respectively, to help distinguish them. One of the two gears, most of which is driven by the rotation of the pinion, the other gear is driven together. Both gears are fluid, especially liquid, and in the vehicle brake system, the brake fluid is passed through the gap between the two gears and sucked into the internal gear pump. Carry from side to discharge side. This is known and will not be described in detail here.

  In any case, Patent Document 1 discloses an example of such an internal gear pump that is expected not for a hydraulic vehicle brake system but for a hydraulic machine, particularly for a construction machine. A conventionally known internal gear pump has a separate piece in a crescent-shaped pump chamber that extends through a circumferential section between two gears that are bounded by a pinion on the inside and a ring gear on the outside. The pinion tooth crown hits the inside thereof, and the ring gear tooth crown hits the outside thereof. The separate piece divides the pump chamber into a suction chamber communicating with the pump inlet and a pressurizing chamber communicating with the pump outlet. Because of its typical crescent or half moon shape, such separate pieces of internal gear pumps are often referred to as crescent pieces. Another name is the filling piece. An internal gear pump having a separate piece in the pump chamber is also called a crescent pump. An internal gear pump having no separate piece is also known, which is also called a gerotor pump. The present invention can be realized in the form of a crescent pump or a gerotor pump.

  In a skid-controlled hydraulic vehicle brake system, the internal gear pump is a check valve on the edge or inside of the pump outlet, if specified, when the pump is stopped, ie when the skid control is not active, the master brake cylinder is activated In this state, the brake fluid flows backward from the pump outlet into the internal gear pump in the direction opposite to the discharge direction of the internal gear pump, and then flows out again from the pump inlet of the internal gear pump. A check valve is needed to prevent the pressure from being lowered and the brake pedal from loosening.

German Patent No. 1961833B4

  The internal gear pump according to the invention having the features described in claim 1 is provided with a cover for sealing the internal gear pump installation space on the front side of the pinion and ring gear, wherein the cover includes the pinion and the ring gear. There may be one or more members between the cover on one side and the pinion / ring gear on the other side. The installation space of the internal gear pump is, for example, the countersunk hole of the hydraulic block of the skid-controlled vehicle brake system in which the internal gear pump is installed, or the inner space of the pump housing, in which the internal gear pump is inserted. The hydraulic block in which the gear pump is incorporated may be understood as the pump housing of the internal gear pump. In particular, for an internal gear pump, a built-in space is expected in which only one front side is open and the other side is closed. However, preferably it is not compulsory that the cover seals the installation space.

  According to the present invention, the pump outlet of the internal gear pump communicates with the cover, the liquid flow from the internal gear pump is passed through the cover through which the pump outlet communicates, and from the pump outlet to the internal gear pump. A check valve is provided to prevent the backflow. This check valve prevents the liquid from the internal gear pump from flowing backward from the pump outlet toward the pump inlet in the direction opposite to the discharge direction when the internal gear pump is stopped. When the internal gear pump is used as a hydropump in a skid-controlled hydraulic vehicle brake system, the check valve discharges brake fluid from the master brake cylinder of the internal gear pump when the internal gear pump is stopped and the master brake cylinder is operating. Block the flow in the opposite direction. Here, the flow in the direction opposite to the discharge direction of the internal gear pump or the flow through the pump outlet into the internal gear pump is referred to as reverse flow.

  The present invention has the advantage of storing the check valve in a space-saving manner at the pump outlet in the cover of the internal gear pump.

  The dependent claims are directed to the advantageous and further developments of the invention as defined in claim 1.

  According to a preferred aspect of the present invention as set forth in claim 3, the check valve in the cover of the internal gear pump is expected to include a damper for reducing the pressure fluctuation of the fluid discharged from the internal gear pump. . The damper can act as a space or volume that houses the check valve, a movable, particularly elastic and / or elastic damper body, or one with a small cross-section at the pump outlet, for example Restrictor or orifice. What is listed is an example and does not end there.

  According to another preferred embodiment of the present invention as set forth in claim 6, the internal gear pump is provided with a filter disposed at the pump outlet between the gear of the internal gear pump and the check valve when viewed in the flow direction. Is expected. The filter prevents solid particles from the internal gear pump, i.e., cutting waste, particles, etc., from reaching the check valve, which can lead to check valve leakage. The form of the internal gear pump according to the invention having a filter at the pump outlet is also conceivable without a check valve.

  A further embodiment of the invention as claimed in claim 7 contemplates placing the filter in the pressure field. The pressure field is on the opposite side of the pinion and ring gear of the axially movable axially movable axial disk that is arcuate or crescent shaped in the circumferential direction over almost all or part of the pump chamber area between the pinion and ring gear. A typical flat shape, countersunk countersink. By applying impulsive pressure to the axial disk from the outside, the axial disk is tightly pressed against the front side of the pinion and the ring gear, thereby sealing the pump chamber on the side surface. Sealing does not necessarily prevent leakage, and the axial disk hits the front side of the pinion, ring gear and separate piece (if provided) like a hydrodynamic axial plain bearing, where Limited leakage between the pinion / ring gear on one side and the axial disk on the other side. It is important to find a good compromise between low friction and proper sealing. Axial discs are also called pressure discs or control discs, or control plates. The shape of the disc or the shape of the plate is not mandatory for the present invention.

  A further embodiment of the invention as claimed in claim 8 allows for the filter arranged in the pressure field to comprise a support element for the pressure field seal, which supports the pressure field seal from the inside. . A pressure field seal is a seal that surrounds a pressure field and seals along its periphery. The skid-controlled hydraulic vehicle brake system is evacuated to avoid air entrainment before filling with brake fluid. The evacuation can cause a negative pressure in the pressure field. The support element of the inventive filter prevents the pressure field seal from entering from the periphery of the pressure field in the pressure field and holds the pressure field seal in its peripheral position surrounding the pressure field.

  Hereinafter, the present invention will be described in detail according to embodiments shown in the drawings.

It is an axial sectional view of the internal gear pump by the present invention. It is an enlarged view of the detail of the rectangle II of FIG.

  The internal gear pump 1 according to the invention depicted in FIG. 1 includes a pump shaft 2 that is rotatably supported in a cover 4 with a bearing (ball bearing 3 in the present embodiment). The cover 4 is a cylindrical part with a flange 5 on one side. This comprises a diametrically parallel, axially parallel passage 6 for passing the pump shaft 2, which is located eccentrically in the cover 4. A gear called a driving wheel 7 is press-fitted to the end of the pump shaft 2 that protrudes from the cover 4, or is arranged so as not to rotate. The driving wheel 7 meshes with a gear referred to as a driving wheel 8 here, and this driving wheel can be driven to rotate by an electric motor (not shown) via a gear device connected in the middle as required.

  On the other side of the ball bearing 3 where the drive wheel 7 is present, a gear with external teeth called a pinion 9 is fitted on the pump shaft 2. The pinion 9 is axially shiftable and is non-rotatably fitted on the pump shaft 2. In this embodiment, the pinion 9 is achieved by the tetrahedron 10 to be axially shiftable and non-rotatable. . However, the present invention is not limited to this possibility. The pinion 9 is arranged in one plane with the pinion 9 and has the same width as the pinion 9, and is in a gear with internal teeth called a ring gear 11 here. Since the ring gear 11 is coaxial with the cylindrical cover 4 and is eccentric with respect to the pump shaft 2 and the pinion 9, the pinion 9 and the ring gear 11 mesh with each other. When the pinion 9 is rotationally driven by the pump shaft 2, the pinion 9 drives the ring gear 11 meshing with the pinion 9 to rotate together. The ring gear 11 is pressed into a bearing ring 12 that is slidably supported in a hydraulic block 15.

  The pinion 9 and the ring gear 11 form a crescent-shaped pump chamber 13 in the circumferential section between them and do not mesh with each other. A half-moon-shaped separate piece is arranged in the pump chamber 13, which divides the pump chamber 13 into a suction chamber and a pressurizing chamber. The separate piece has the same width as the pinion 9 and the ring gear 11. This separate piece, also called a filling piece or a crescent piece because of its shape, is outside the cut surface and is therefore not visible in the figure. By rotating the pinion 9 and the ring gear 11, the internal gear pump 1 causes fluid (brake fluid in this embodiment) to flow from the suction chamber of the tooth gap between the pinion 9 and the ring gear 11 along the inside and outside of the separate piece. To send.

  A seal device including a collar seal 16, a support ring 17 and a secondary seal 18 is disposed between the ball bearing 3 and the pinion 9, and seals the pump shaft 2 in the cover 4. The collar seal 16 has a trumpet funnel shape and is arranged to be pressed against the pump shaft 2 when pressure is applied. The support ring 17 between the ball bearing 3 and the color seal 16 has a ring front surface that is curved in a concave shape in accordance with the convex shape of the color seal 16, and the color seal 16 is in contact therewith. The secondary seal 18 is a seal ring disposed in the front groove of the ring step of the through hole 6 in the cover 4. The secondary seal 18 is on the side facing the support ring 17 along the outer peripheral edge of the collar seal 16, and sandwiches the outer edge of the collar seal 16 between itself and the support ring 17.

  There is an axial disk 19 between the sealing device 16, 17, 18 on one side and the pinion 9 and ring gear 11 on the other side, which hits the front side of the pinion 9, the ring gear 11 and the separate piece. The axial disk 19 has a through hole for the pump shaft 2. The axial disk 19 is stationary and movable in the axial direction. At first glance, the axial disk 19 has an arcuate shape with an area larger than a semicircle, and a step is carved at the corner. The axial disk 19 covers the separate piece and the pressurizing chamber of the pump chamber 13 on one side.

  The cover 4 has a pressure field 20 on the inner side facing the axial disk 19, that is, on the outer side of the axial disk 19 opposite to the pinion 9 and the ring gear 11. The pressure field 20 is a substantially semicircular flat recess that extends approximately over the pressurization chamber of the pump chamber 13 and a portion of the separate piece. The pressure field 20 is surrounded by a pressure field seal 21, which seals the pressure field 20 between the cover 4 and the axial disk 19. Instead of being as illustrated, the cover 4 may be provided with a pressure field 20 outside the axial disk 19 (not shown). The axial disk 19 has a through hole 22 that leads from the pressurizing chamber of the pump chamber 13 into the pressure field 20. Since the pressure field 20 communicates with the pressurizing chamber of the pump chamber 13 of the internal gear pump 1 through the through hole 22, the pressure field 20 is controlled by the same pressure as the pump outlet. By applying impulsive pressure in the pressure field 20, the axial disk 19 is pressed tightly against the front side of the pinion 9, the ring gear 11 and the separate piece. The axial disk 19 hits the front side of the pinion 9, the ring gear 11 and the separate piece like a kind of sliding bearing, but does not prevent leakage. Select the optimum relationship or at least the preferred relationship between the friction between the rotating pinion 9 on the one hand and the rotating ring gear 11 on the other hand, the friction between the rotating pinion 9 on the other hand and the non-rotating axial disk 19 and the small leakage. Less leakage can be selected experimentally by the size, shape and position of the pressure field 20. From the pressure field 20, the bent bore hole extends short in the cover 4 in the axial direction and then extends radially outward to the periphery of the cover 4. The through hole 22 of the axial disk 19 and the bent bore hole of the cover 4 are components of the pump outlet of the internal gear pump 1. The bent bore hole of the cover 4 leads into the ring groove 23 in the hydraulic block 15 already described, and this surrounds the cover 4 at the height of the radial portion of the bent bore hole. The ring groove 23 is also provided in the hydraulic block 15 and intersects with an outlet bore hole 24 which is a constituent part of the pump outlet, like the ring groove 23. The outlet bore hole 24 communicates with the master brake master cylinder via a separate valve and communicates with the wheel brake via a booster valve. The separate valve, booster valve, master brake cylinder and wheel brake are not shown.

  The separate valve and the booster valve are electromagnetic valves incorporated in the hydraulic pressure block 15, but in any case, they are outside the cut surface and are not seen in the drawing. The master brake cylinder and the wheel brake are located outside the hydraulic block 15 and are connected by a brake line.

  The cover 4 is provided with two seal rings 25 on both sides of the entrance / exit of the bent bore hole leading to the peripheral edge of the cover 4, and thus also on both sides of the ring groove 23 of the hydraulic block 15, It is arranged inside and seals both sides of the ring groove 23 between the hydraulic block 15 and the cover 4.

  Similar to the axial disk 19, the internal gear pump 1 is provided with a pressure disk 26 closely contacting the front side of the pinion 9, the ring gear 11, and the separate piece on the side where the pinion 9 and the ring gear 11 face each other. The pressure disk 26 is arranged in the hydraulic block 15 so that it cannot move, that is, it does not rotate, does not move in the radial direction, and does not move in the axial direction. The pressure disk 26 is circular. The pressure disk 26 is provided with a cylindrical through hole coaxial with the pump shaft 2 at an eccentric position, which forms a bearing 27, so that the end of the pump shaft 2 far from the drive wheel 7 can slide freely. Has been. For the sliding bearing of the pump shaft 2, a sliding bearing bush (not shown) may be pressed into the hole 27 of the pressure disk 26 or alternatively fixed there. It is also possible to roll-support the pump shaft 2 on the pressure disk 26 using a rolling bearing (not shown).

  By applying pressure to the outside of the axial disk 19 in the pressure field 20, the axially movable axial disk 19 is pressed against the front side of the pinion 9, the ring gear 11 and the separate piece, and on the opposite side of the axial disk 19, The front side of the axially movable pinion 9, the axially movable ring gear 11 and the axially movable separate piece is pressed against the inside of the pressure disk 26 facing the pinion 9, and as a result, the pinion 9 and the ring gear 11 The front side of the separate piece also closely contacts the pressure disk 26. Again, the way of hitting is like a kind of plain bearing, not leaking but showing leaking.

  The hydraulic block 15 includes a stepped bag hole as a built-in space 28 for the internal gear pump 1, and the gear pump 1 is fitted therein and fixed by, for example, caulking. The hydraulic block 15 is part of a skid control (not shown) of the hydraulic vehicle brake system. The hydraulic block 15 is a rectangular member made of an aluminum alloy, a second countersink as a mounting space 28 for the second internal gear pump 1 and a further countersink for a hydraulic component of the skid control. It comprises. Such components are solenoid valves and accumulators not shown. An electric motor (not shown) is connected to the outside of the hydraulic block 15 by flange, and the drive wheel 7 is connected to the motor shaft or to the gear shaft of the gear device flange-connected to the electric motor. A driving wheel 8 for driving both internal gear pumps 1 is fitted through the wheel. The receiving holes for the hydraulic components are connected to each other through the bore holes of the hydraulic block 15 so that the hydraulic components (not shown) of the skid control are hydraulically connected to each other. The hydraulic block 15 with hydraulic components and with the electric motor and further electrical components, electromechanical components and electronic components now forms the skid control unit and hydraulic unit of the hydraulic vehicle brake system.

  A pump inlet arranged at an angle with respect to the pump outlet 29 may pass through the cover 4 and the axial disk 19 in the same way as the pump outlet 29, or a countersink in the hydraulic block 15 forming an installation space 28. May pass through a through hole in the pressure disk 26 at the bottom. Since the pump inlet is outside the cut surface, it is not visible in the drawing.

  The pressure field seal 21 is a seal having a stepped ring cross-section surrounding the meniscus pressure field 20. The front surface of the pressure field seal 21 is in contact with the outside of the axial disk 19. The pressure field seal 21 is provided with a seal bead at a position that is opposed to this and shifted outward in the direction of the cover 4, which hits the bottom of the pressure field 20 in the cover 4. In the ring stage outside the pressure field seal 21, the support ring 30 faces the axial disk 19 and surrounds the pressure field seal 21 to support the pressure field seal 21 from the outside.

  Inside the pressure field seal 21, a filter 31 is arranged in the pressure field 20. The filter 31, for example a fabric fiber filter, is covered with a flange-shaped frame 32 along its edge, the shape of which is half-moon shaped depending on the pressure field 20 and the inside of the pressure field seal 21. Similarly, the internal free space of the frame 32 with the filter 31 in it is also half-moon shaped to guarantee a large area of the filter. Since the flange-shaped frame 32 of the filter 31 is smaller than the inner periphery of the pressure field seal 21, there is a gap 33 (see FIG. 2) between the frame 32 of the filter 31 and the pressure field seal 21 along the periphery. The flange-like frame 32 of the filter 31 is flatter than the pressure field 20 with a depth, so that there is a gap 34 between the side of the frame 32 of the filter 31 facing the axial disk 19 and the axial disk 19. Through the gap 22 between the through hole 22 of the axial disk 19, the frame 32 of the filter 31 and the axial disk 19 and the pressure field seal 21, the pressure field 20 is connected to the pressurizing chamber of the pump chamber 13 of the internal gear pump 1. contact. By applying pressure, the pressure field seal 21 is tightly pressed against the axial disk 19 and also to the periphery and / or bottom of the pressure field 20 of the cover 4. A gap 34 between the frame 32 of the filter 31 and the axial disk 19 is part of the pressure field 20.

  The frame 32 of the filter 31 includes a collar 35 that protrudes toward the bottom of the pressure field 20 and is in a mating cover surrounding the collar 35, ie, the pressure field 20, with a seal bead protruding outward. It closely contacts the facing collar 14 on the cover 4 side. The color 35 of the frame 32 of the filter 31 surrounds the internal free space of the frame 32 in which the filter 31 is disposed.

  The frame 32 of the filter 31 forms a support element that supports the pressure field seal 21 from the inside. When the hydraulic block 15 is evacuated by the internal gear pump 1 before the vehicle brake system is filled with brake fluid, the frame 32 of the filter 31 forming the support element has the pressure field seal 21 facing the pressure field 20 inward. The pressure field seal 21 is held in a position provided at the periphery of the pressure field 20 for this purpose.

  Inside the collar 35, a through hole 36 leads to the bottom of the pressure field 20. The through hole 36 penetrates the cover 4 of the internal gear pump 1 in parallel with the axis. As viewed from the pressure field 20, the through hole 36 first expands in a tapered manner while forming the valve seat 37, and then expands with the two ring stages. A check valve 38 is arranged in the through hole 36 and comprises a disc-shaped valve body 39 and a valve stem 41 having an annular sealing surface 40 cooperating with the valve seat 37.

  The valve stem 41 penetrates into the tubular damper main body 42, and the valve stem 41 is caught in a hole provided in the lateral wall 43 inside. Since the hole provided in the lateral wall 43 of the damper main body 42 is larger than the valve shaft portion 41, a passage exists there.

  On the opposite side of the pressure field 20, the stepped through hole 36 of the cover 4 is pressure-tightly sealed with a cap 44. The cap 44 is pressed into the through hole 36 and is held in a pressure-tight manner by, for example, caulking (not shown). The cap 44 is in contact with the ring step of the through hole 36. The damper body 42 can move in the through hole 36, and a spring element 45 in the form of a coil compression spring arranged between the cap 44 and the lateral wall 43 of the damper body 42 presses the damper body 42 and reverses through it. The closing body 39 of the stop valve 38 is pressed against the valve seat 37. Since it can move in the through hole 36, the damper main body 42 reduces the pressure vibration of the brake fluid flowing out through the check valve 38 when the internal gear pump 1 is operated.

  The closing body 39 of the check valve 38 and the end of the damper body 42 facing this are surrounded by a ring channel 46 which is formed following the valve seat 37 as a relief groove of the through hole 36. A pump outlet 29 extending in the radial direction in the cover 4 passes through the ring channel 46. The pump outlet 29 is axially offset with respect to the ring channel 46 in such a way that the pump outlet 29 is a cut in the ring channel 46. This creates a step with a small flow cross section, which also serves to alleviate pressure oscillations at the pump outlet.

  A passage 22 of the axial disk 19 communicating with the pressurizing chamber in the pump chamber 13 of the internal gear pump 1, a free space inside the frame 32 of the filter 31, a passage 36 to the damper main body 42, and a check valve 38 are closed. The ring channel 46 surrounding the body 39, the cover 4 surrounding the seal ring 25, and the ring groove 23 of the hydraulic block 15 through which the radial portion of the pump outlet 29 communicates, and intersects this ring groove 23 An outlet bore hole 24 in the hydraulic block 15 forms the pump outlet.

DESCRIPTION OF SYMBOLS 1 Internal gear pump 2 Pump shaft 4 Cover 6 Passage hole 9 Pinion 11 Ring gear 13 Pump chamber 15 Hydraulic block 19 Axial disk 20 Pressure field 21 Pressure field seal 26 Pressure disk 28 Installation space 29 Pump outlet 30 Support ring 31 Filter 32 Support element Or frame 36 through hole 37 valve seat 38 check valve

Claims (10)

  A ring gear (11), a pinion (9) that is eccentrically arranged in the ring gear (11) and meshes with the ring gear (11), and a pinion (9) of the internal gear pump (1) and the front of the ring gear (11) An internal gear pump having a cover (4) disposed on the side and sealing a built-in space (28) of the internal gear pump (1), wherein the pump outlet (29) of the internal gear pump (1) Passing through the cover (4), and the cover (4) allows the liquid flow from the internal gear pump (1) to pass through the pump outlet (29) at the pump outlet (29). An internal gear pump comprising a check valve (38) for preventing back flow to the internal gear pump (1).   The cover (4) has a stepped hole (36) as a built-in space for the check valve (38), and the valve of the check valve (38) in the step of the hole (36) 2. Internal gear pump according to claim 1, characterized in that the seat (37) is shaped.   The internal gear pump according to claim 1, wherein the check valve (38) includes a damper for relaxing pressure vibration of the liquid discharged from the internal gear pump (1).   4. The internal gear pump according to claim 3, wherein the check valve (38) comprises an elastic and / or elastic damper body (42).   The pump outlet (29) has a small flow cross section in the cover (4) of the internal gear pump (1) in order to alleviate pressure oscillations of the fluid discharged from the internal gear pump (1). The internal gear pump according to claim 3, wherein   The internal gear pump (1) passes the filter (31) in the cover (4) through which the pump outlet (29) passes, and the check valve (38) in the direction of outflow from the internal gear pump (1). The internal gear pump according to claim 1, wherein the internal gear pump is provided in front of.   The internal gear pump (1) is provided with an axial disk (19) which is stationary and axially movable, and the axial disk (19) is connected to the pinion (9) and the ring gear (11) on one side and the other side. Arranged between the cover (4) on the side, which also comprises a pressure field (20) on the outer side opposite to the pinion (9) and the ring gear (11), when pressure is applied thereto The axial disk (19) is pressed tightly on the front side of the pinion (9) and ring gear (11), and the filter (31) is arranged in the pressure field (20). The internal gear pump according to claim 6.   The pressure field (20) comprises a pressure field seal (21) surrounding the pressure field (20), and the filter (31) provides the pressure field seal (21) for the pressure field seal (21). 8. The internal gear pump according to claim 7, further comprising a support element (32) for supporting the field seal (21) on the inside.   9. The internal gear pump according to claim 8, wherein the filter (31) and the support element (32) have a one-piece structure.   9. The internal gear pump according to claim 8, wherein the filter (31) comprises a sealing collar (35).

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