Hydraulic pump

Abstract

To provide a hydraulic pump which has a single member having a plurality of functions to reduce the number of part items, and can be simplified in a constitution.SOLUTION: An insertion hole 16 into which an input shaft 12h is inserted is formed in a casing 1, and the insertion hole 16 is opened in one side face 2A of the casing 1. The input shaft 12 protrudes to the outside in an axial direction at its tip side with respect to an opening of the insertion hole 16. A sealing member 18 for sealing the inside of the casing 1 while slide-contacting with the input shaft 12 is arranged in the insertion hole 16. An annular collar member 19 into which the input shaft 12 is inserted while adjoining the outside of the sealing member 18 in an axial direction is fixedly arranged in the insertion hole 16. The collar member 19 protrudes to the outside in the axial direction with respect to one side face 2A of the casing 1 at one end side in the axial direction, and has a protrusion 7 which is spigot-fit to an electric motor 8.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a hydraulic pump that sucks in and discharges liquid by rotating an input shaft with an output shaft of an electric motor, and more particularly to a hydraulic pump that is directly attached to an electric motor by spigot-fitting a protrusion thereon. [Background technology]

[0002] This type of hydraulic pump houses a drive gear and a driven gear that mesh with each other and constitute the pump mechanism inside a casing, and sucks in and expels liquid by driving the rotation of both gears. The input shaft that is formed integrally with the drive gear passes through an insertion hole (bearing hole) formed in a front cover that constitutes the casing and protrudes outward in the axial direction. A sealing member (oil seal) that seals the insertion point of the input shaft is disposed in the insertion hole, and the sealing member is prevented from coming off by a C-shaped snap ring. In addition, a protrusion is formed on the front cover that protrudes in the axial direction radially outward from the insertion hole and concentric with the input shaft, and the protrusion is directly attached to the electric motor by fitting the protrusion to the electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2008 / 029477 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in such conventional hydraulic pumps, the snap ring has the function of preventing the sealing member from coming off, and the protrusion has the function of fitting into the electric motor, and since the snap ring and the protrusion each have only one function, there was a problem in that the number of parts was increased.

[0005] An object of the present invention is to provide a hydraulic pump having a plurality of functions in one member, thereby reducing the number of parts and simplifying the configuration. [Means for solving the problem]

[0006] In order to achieve this object, the present invention takes the following measures: In this hydraulic pump, an input shaft is rotationally driven by the output shaft of an electric motor, and liquid is sucked in and discharged by a pump mechanism provided inside a casing when the input shaft is rotated, and the pump is directly attached to the electric motor by a spigot fitting of a protrusion, wherein the casing is formed with an insertion hole through which the input shaft passes, the insertion hole opens to one side of the casing, the tip side of the input shaft protrudes axially outward from the opening of the insertion hole, a sealing member is disposed in the insertion hole by sliding contact with the input shaft to seal the inside of the casing, and an annular collar member through which the input shaft passes is fixed to the insertion hole adjacent to the axially outward side of the sealing member, one axial end side of the collar member protrudes axially outward from one side of the casing, and one axial end side of the collar member is a protrusion that is spigot fitted into the electric motor.

[0007] In this case, the collar member may be press-fitted into the insertion hole. Also, the collar member may have a threaded hole into which a bolt member can be screwed, so that the collar member can be pulled out of the insertion hole by the bolt member. Effect of the Invention

[0008] As described above in detail, the invention described in claim 1 has a casing having an insertion hole through which an input shaft is inserted, the insertion hole opening on one side of the casing, the input shaft having a tip end protruding axially outward from the opening of the insertion hole, a sealing member arranged in the insertion hole that comes into sliding contact with the input shaft to seal the inside of the casing, an annular collar member through which the input shaft is inserted is fixed to the insertion hole adjacent to the axially outward side of the sealing member, one axial end side of the collar member protruding axially outward from one side of the casing, and the one axial end side of the collar member being a convex portion that is spigot-fitted with the electric motor. Therefore, the collar member has a function of preventing the sealing member from coming off the insertion hole and a function of spigot-fitting with the electric motor, so that one member has multiple functions, reducing the number of parts and simplifying the configuration.

[0009] In the invention described in claim 2, the collar member is press-fitted into the insertion hole, which makes it possible to easily fix the collar member and facilitates assembly of the hydraulic pump.

[0010] In the invention described in claim 3, a threaded hole into which a bolt member can be screwed is formed in the collar member, and the collar member can be pulled out of the insertion hole by the bolt member. Therefore, since the bolt member attached to the collar member can be easily grasped by an operator, the collar member can be easily removed from the pump housing during maintenance and inspection. [Brief description of the drawings]

[0011] [Figure 1] 1 is a vertical sectional view of a hydraulic pump according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a cross-sectional view taken along line AA in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line BB in FIG. [Figure 4] FIG. 2 is a cross-sectional view taken along line CC in FIG. [Diagram 5] FIG. 11 is a longitudinal sectional view of a main portion showing another embodiment. [Figure 6] FIG. 11 is a longitudinal sectional view of a main portion showing still another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In Figures 1 and 2, reference numeral 1 denotes a casing which is composed of a front body member 2, a rear body member 3, and an intermediate member 4. The intermediate member 4 is sandwiched between the front body member 2 and the rear body member 3. As shown in Figures 3 and 4, the casing is positioned by two pin members 5 which pass between the members 2, 3, and 4, and is fastened together by four bolt members 6.

[0013] Reference numeral 7 denotes a convex portion which is spigot-fitted into a concave portion 9 of the electric motor 8. Reference numeral 10 denotes the output shaft of the electric motor 8, which has a hole 11 drilled at its tip. Reference numeral 12 denotes an input shaft which is inserted into the hole 11 of the output shaft 10 by spigot-fitting the convex portion 7 into the concave portion 9, and engages in the rotational direction with a key 13. The input shaft 12 is rotated by the output shaft 10, and sucks in and discharges liquid with a pump mechanism 14, which will be described in detail later. Reference numeral 15 denotes two bolt members which are arranged spaced apart in a direction perpendicular to the axial direction, and with the convex portion 7 spigot-fitted into the concave portion 9, they are inserted through a flange portion formed on the front main body member 2 and screwed to the electric motor 8, and the casing 1 is directly attached to the electric motor 8.

[0014] Reference numeral 16 denotes an insertion hole formed axially penetrating front main body member 2 constituting casing 1 and opening to one side surface 2A. Reference numeral 17 denotes a ball bearing that journals input shaft 12, with an outer ring fixed axially to insertion hole 16 and an inner ring fixed axially to input shaft 12. Reference numeral 18 denotes an oil seal as a sealing member, which is arranged axially outside of ball bearing 17 with its outer periphery pressed against insertion hole 16 and has an inner lip portion that slides against input shaft 12 to seal the inside of casing 1.

[0015] Reference numeral 19 denotes a cylindrical collar member having an annular shape, which is press-fitted into the insertion hole 16 and fixed adjacent to the axially outward side of the oil seal 18. The collar member 19 has a through hole 20 formed in the radial center in the axial direction, through which the input shaft 12 is inserted. The through hole 20 has a diameter larger than the input shaft 12, and has a radial gap between it and the input shaft 12. One axial end of the collar member 19 protrudes axially outward from one side surface 2A of the front main body member 2 constituting the casing 1, and serves as a protrusion 7 that is spigot-fitted into the recess 9 of the electric motor 8. The other axial end of the collar member 19, which is opposite to the one axial end, is capable of abutting the oil seal 18, and prevents the oil seal 18 from slipping out to the outside.

[0016] 2, reference numeral 21 denotes two screw holes that axially penetrate collar member 19 and are formed at positions spaced equally apart in the circumferential direction radially outward of through hole 20. With casing 1 removed from motor 8, a bolt member (not shown) can be screwed into each screw hole 21 from one axial end side of collar member 19, and during maintenance and inspection, an operator holds the bolt member and removes collar member 19 from casing 1.

[0017] 1 to 4, the pump mechanism 14 is a double external gear pump mechanism in which a first drive gear 22 externally meshes with a first driven gear 23, and a second drive gear 24 externally meshes with a second driven gear 25. Each of the gears 22 to 25 has the same shape and a plurality of external teeth.

[0018] Reference numeral 26 denotes a first gear housing hole, which is recessed in one side surface 2A of the front main body member 2 and the other side surface 2B opposite thereto, and has a cross section formed in a substantially figure-8 shape. The opening of the first gear housing hole 26 is closed by the intermediate member 4, and an insertion hole 16 is opened in the bottom surface of the first gear housing hole 26. The first gear housing hole 26 rotatably houses a first driving gear 22 and a first driven gear 23, and the external teeth of the first gears 22, 23 slide against the inner peripheral surface of the first gear housing hole 26. The first driving gear 22 is axially movable and engaged with the input shaft 12 by four keys 27. The second driven gear 23 is axially movable and engaged with the driven shaft 28 by four keys 29.

[0019] Reference numeral 30 denotes a first suction port for sucking in liquid, which opens into the bottom surface of the first gear housing hole 26 on one side of the position where the first gears 22, 23 mesh. Reference numeral 31 denotes a first discharge port for discharging liquid, which opens into the bottom surface of the first gear housing hole 26 at a position symmetrical to the position where the first suction port 30 opens, with respect to the position where the first gears 22, 23 mesh.

[0020] The input shaft 12 and the driven shaft 28 are arranged approximately parallel to the axial direction, and pass through the front body member 2, the intermediate member 4, and the rear body member 3. The input shaft 7 is supported by a ball bearing 17 and a first plain bearing 32 arranged on the rear body member 3. The driven shaft 28 is supported by a second plain bearing 33 arranged on the front body member 2, and a third plain bearing 34 arranged on the rear body member 3.

[0021] Reference numeral 35 denotes a second gear housing hole, which is formed as a recess in one side surface 3A of the rear main body member 3 and has a cross section formed into a substantially figure-8 shape. The opening of the second gear housing hole 35 is closed by the intermediate member 4. The second gear housing hole 35 rotatably houses the second driving gear 24 and the second driven gear 25, and the external teeth of both second gears 24, 25 slide against the inner peripheral surface of the second gear housing hole 35. The second driving gear 24 is axially movable and engaged with the input shaft 12 by four keys 36 in the rotational direction. The second driven gear 25 is fitted to the driven shaft 28 so as to be axially movable and rotatable in the rotational direction.

[0022] Reference numeral 37 denotes a second suction port for sucking in liquid, which opens into the bottom surface of the second gear housing hole 35 on one side of the position where the second gears 24, 25 mesh. Reference numeral 38 denotes a second discharge port for discharging liquid, which opens into the bottom surface of the second gear housing hole 35 at a position symmetrical to the position where the second suction port 37 opens across the position where the second gears 24, 25 mesh.

[0023] Next, the operation of this configuration will be described. When the input shaft 12 is rotationally driven by the output shaft 10 of the electric motor 8, the first drive gear 22 and the second drive gear 24 are rotationally driven together with the input shaft 12 in the same direction, and the first driven gear 23 and the second driven gear 25, which mesh with the two drive gears 22, 24, are rotationally driven in the opposite direction to the two drive gears 22, 24.

[0024] The liquid in the first suction port 30 is sucked between the external teeth of the first driving gear 22 and between the external teeth of the first driven gear 23, transported along the inner circumference of the first gear housing hole 26, and discharged from the first discharge port 31. Meanwhile, the liquid in the second suction port 37 is sucked between the external teeth of the second driving gear 24 and between the external teeth of the second driven gear 25, transported along the inner circumference of the second gear housing hole 35, and discharged from the second discharge port 38.

[0025] In this operation, the casing 1 is formed with an insertion hole 16 through which the input shaft 12 is inserted, the insertion hole 16 opens to one side surface 2A of the casing 1, the tip side of the input shaft 12 protrudes axially outward from the opening of the insertion hole 16, a sealing member 18 that slides against the input shaft 12 and seals the inside of the casing 1 is disposed in the insertion hole 16, an annular collar member 19 through which the input shaft 12 is inserted is fixed to the insertion hole 16 adjacent to the axially outward side of the sealing member 18, one axial end side of the collar member 19 protrudes axially outward from the one side surface 2A of the casing 1, and one axial end side of the collar member 19 serves as a protrusion 7 that is spigot-fitted with the electric motor 8. Therefore, the collar member 19 has a function of preventing the sealing member 18 from coming off the insertion hole 16 and a function of spigot-fitting with the electric motor 8, so that one member has multiple functions, reducing the number of parts and simplifying the configuration.

[0026] Furthermore, collar member 19 is fixed to insertion hole 16. Therefore, it is not necessary for collar member 19 to have a radial dimension larger than insertion hole 16, so compared to conventional pumps in which a convex portion for fitting with a spigot is formed radially outward of the insertion hole, the radial dimension of the spigot-fitting convex portion 7 can be made smaller, and the entire hydraulic pump can be made smaller.

[0027] Furthermore, the collar member 19 is press-fitted into the insertion hole 16. Therefore, the collar member 19 can be easily fixed, and the assembly of the hydraulic pump can be facilitated.

[0028] In addition, a threaded hole 21 into which a bolt member can be screwed is formed in the collar member 19, so that the collar member 19 can be pulled out of the insertion hole 16 by the bolt member. Therefore, since the bolt member attached to the collar member 19 can be easily grasped by an operator, the collar member 19 can be easily removed from the pump housing 1 during maintenance and inspection, etc.

[0029] FIG. 5 shows another embodiment of the present invention. The same parts as those in the first embodiment are given the same reference numerals and their explanation is omitted, and only the different parts will be explained. The collar member 19A has one axial end protruding outward in the axial direction formed with a diameter larger than that of the insertion hole 16 to form a flange shape, and the protrusion 7A has a diameter larger than that of the protrusion 7 in one embodiment. The protrusion 7A is spigot-fitted into the large-diameter recess 9A. Therefore, by changing the collar member 19A, which is smaller and easier to handle than the casing 1, it can be attached to the electric motor 8 that forms the large-diameter recess 9A without changing the casing 1.

[0030] FIG. 6 shows still another embodiment of the present invention. The same parts as those in the first embodiment are designated by the same reference numerals and their explanation is omitted, and only the different parts will be explained. The collar member 19B has one axial end protruding outward in the axial direction formed with a smaller diameter than the insertion hole 16, forming a convex portion 7B with a smaller diameter than the convex portion 7 of one embodiment. The convex portion 7B is spigot-fitted into the small-diameter concave portion 9B. Therefore, by changing the collar member 19B, which is smaller and easier to handle than the casing 1, it can be attached to the electric motor 8 that forms the small-diameter concave portion 9B without changing the casing 1.

[0031] In the above embodiment, the pump mechanism 14 is a double external gear pump mechanism in which the first drive gear 22 and the first driven gear 23 are externally meshed with each other and the second drive gear 24 and the second driven gear 25 are externally meshed with each other, but it may be an external gear pump mechanism in which one drive gear is externally meshed with one driven gear, an internal gear pump mechanism in which an external gear is eccentrically accommodated inside an internal gear and the internal gear and the external gear are internally meshed with each other, a vane pump mechanism having multiple vanes on a rotor, or a piston pump mechanism having multiple pistons slidably provided in a cylinder block. Also, the collar members 19, 19A, and 19B fixed to the insertion hole 16 are press-fitted into the insertion hole 16, but it goes without saying that the collar members may be screwed or glued into the insertion hole. [Explanation of symbols]

[0032] 1: Casing 7, 7A, 7B: Convex 8: Electric motor 10: Output shaft 12: Input shaft 14: Pump mechanism 16:Through hole 18: Oil seal (sealing material) 19, 19A, 19B: Color parts

Claims

1. 1. A hydraulic pump in which an input shaft is rotationally driven by an output shaft of an electric motor, and liquid is sucked in and discharged by a pump mechanism provided inside a casing when the input shaft is rotated, and which is directly attached to the electric motor by a spigot fitting of a protrusion, wherein the casing is formed with an insertion hole through which the input shaft passes, the insertion hole opening into one side of the casing, a tip side of the input shaft protruding axially outward from the opening of the insertion hole, a sealing member is disposed in the insertion hole by sliding contact with the input shaft to seal the inside of the casing, and an annular collar member through which the input shaft passes is fixed to the insertion hole adjacent to the axially outward side of the sealing member, one axial end side of the collar member protruding axially outward from one side of the casing, and one axial end side of the collar member is a protrusion that is spigot fitted into the electric motor.

2. 2. The hydraulic pump according to claim 1, wherein the collar member is press-fitted into the insertion hole.

3. 3. The hydraulic pump according to claim 2, wherein said collar member is formed with a threaded hole into which a bolt member can be screwed, and said collar member can be pulled out of said insertion hole by the bolt member.

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