JP7540262B2 - Electric pump - Google Patents

Description

The present invention relates to an electric pump.

Electric pumps are known that have a structure that returns a portion of the fluid discharged from the discharge flow passage to the pump chamber. For example, Patent Document 1 describes an electric pump that is used to supply oil for lubrication of automobile engines, etc.

JP 2009-162146 A

In electric pumps like the one described above, the pressure of the fluid in the pump chamber may fluctuate due to some of the fluid returning from the discharge flow path to the pump chamber, causing the pressure of the fluid discharged from the discharge flow path to pulsate.

In view of the above circumstances, one of the objects of the present invention is to provide an electric pump having a structure capable of suppressing pressure pulsation of the fluid discharged from the discharge flow path.

One aspect of the electric pump of the present invention includes a motor unit, a pump mechanism connected to the motor unit, a housing having a pump chamber that houses the pump mechanism, an intake flow path connected to the pump chamber, a discharge flow path connected to the pump chamber, and a relief flow path extending from the discharge flow path to the intake flow path, and a relief valve provided in the relief flow path. The housing has an intake opening that opens to the outside of the housing. The intake flow path has a first intake flow path portion extending from the intake opening and a second intake flow path portion that bends and extends from the first intake flow path portion. The relief flow path has a first relief flow path portion extending from the discharge flow path and a second relief flow path portion extending from the first relief flow path portion to the intake flow path. The relief valve is switchable between a state in which the first relief flow path portion and the second relief flow path portion are connected to each other and a state in which the first relief flow path portion and the second relief flow path portion are blocked from each other. The second relief flow passage portion is connected to the connection portion between the first and second intake flow passage portions of the intake passage or to the first intake flow passage portion.

According to one aspect of the present invention, it is possible to suppress pressure pulsations of the fluid discharged from the discharge flow path in an electric pump.

FIG. 1 is a partial cross-sectional view showing an electric pump according to the present embodiment. FIG. 2 is a perspective view showing each flow path of the present embodiment. FIG. 3 is a cross-sectional view showing a part of the electric pump of this embodiment, taken along line III-III in FIG. FIG. 4 is a cross-sectional view showing a part of the electric pump of this embodiment, taken along line IV-IV in FIG. FIG. 5 is a partially cutaway perspective view showing a part of the electric pump of the present embodiment.

Each figure shows an X-axis, a Y-axis perpendicular to the X-axis, and a Z-axis perpendicular to the X-axis and Y-axis. In the following explanation, the direction parallel to the Z-axis is called the "up-down direction", the direction parallel to the Y-axis is called the "left-right direction", and the direction parallel to the X-axis is called the "front-back direction". The up-down direction, left-right direction, and front-back direction are perpendicular to each other.

In the up-down direction, the positive side (+Z side) where the Z-axis arrow points is called the "upper side," and the negative side (-Z side) opposite the side where the Z-axis arrow points is called the "lower side." In the left-right direction, the positive side (+Y side) where the Y-axis arrow points is called the "left side," and the negative side (-Y side) opposite the side where the Y-axis arrow points is called the "right side." In the front-to-back direction, the positive side (+X side) where the X-axis arrow points is called the "front side," and the negative side (-X side) opposite the side where the X-axis arrow points is called the "rear side."

Note that the terms up-down, left-right, front-rear, upper, lower, left side, right side, front, and rear are simply names used to describe the relative positions of the various parts, and the actual relative positions may be other than those indicated by these names.

The electric pump 10 of this embodiment shown in FIG. 1 is an electric oil pump that pumps oil O as a fluid. The electric pump 10 is mounted on, for example, a vehicle. As shown in FIG. 1, the electric pump 10 of this embodiment includes a housing 20, a motor unit 30, a pump mechanism 40, a control device 50, and a busbar assembly 80. In addition, as shown in FIG. 2, the electric pump 10 includes a relief valve 70.

As shown in FIG. 1, the housing 20 accommodates the motor section 30 and the pump mechanism 40 inside. In this embodiment, the housing 20 is configured by connecting a number of separate members. In this embodiment, the housing 20 has a housing main body 21, a first cover 22, and a second cover 23. The housing main body 21, the first cover 22, and the second cover 23 are each made by die casting, for example.

As shown in FIG. 2, the housing body 21 has a base 21a and a protruding portion 21b. The protruding portion 21b protrudes, for example, to the left from the rear end portion of the base 21a. As shown in FIG. 1, the first cover 22 is attached to the right side of the housing body 21. The first cover 22 is provided with a breather 27. The second cover 23 is attached to the left side of the housing body 21.

The housing 20 has a motor housing 24, a pump chamber 25, a connection hole 26, an intake port 28a, and a discharge port 28b. The motor housing 24 is a portion in which the motor unit 30 is housed. The motor housing 24 is configured, for example, by a recess recessed from the right side surface of the housing body 21 to the left side being covered from the right side by the first cover 22. At the left end of the motor housing 24, a bearing holder 24a and a seal holder 24b are provided, which reduce the inner diameter of the motor housing 24. The seal holder 24b is located to the left of the bearing holder 24a. An oil seal 90 is provided in the seal holder 24b. The oil seal 90 seals between the inner circumferential surface of the seal holder 24b and the outer circumferential surface of the shaft 31a described later.

The pump chamber 25 is located, for example, on the left side of the motor housing 24. The pump chamber 25 houses the pump mechanism 40. The pump chamber 25 is formed, for example, by a recess recessed from the left side surface of the housing body 21 to the right side, which is blocked from the left side by the second cover 23. The connection hole portion 26 extends in the left-right direction and connects the interior of the motor housing portion 24 and the interior of the pump chamber 25.

The suction port 28a and the discharge port 28b are recessed to the right from the right side of the inner surface of the pump chamber 25. The inside of the suction port 28a and the inside of the discharge port 28b are connected to the inside of the pump chamber 25. Oil O is drawn into the pump chamber 25 from the suction port 28a. The oil O drawn into the pump chamber 25 is discharged from the discharge port 28b.

2, the housing 20 has an intake opening 60a and an exhaust opening 60b. The intake opening 60a and the exhaust opening 60b open to the outside of the housing 20. The intake opening 60a and the exhaust opening 60b open, for example, to the rear side. The intake opening 60a and the exhaust opening 60b open, for example, to the rear surface of the base 21a in the housing main body 21. The intake opening 60a and the exhaust opening 60b are, for example, circular. The exhaust opening 60b is, for example, located to the left of the intake opening 60a and above the intake opening 60a. Oil O is sucked into the housing 20 from the intake opening 60a. The oil O sucked into the housing 20 is discharged to the outside of the housing 20 from the exhaust opening 60b.

The housing 20 has an intake passage 61, a discharge passage 62, and a relief passage 63. The cross-sectional shapes of the intake passage 61, the discharge passage 62, and the relief passage 63 are, for example, circular.

The intake passage 61 is connected to the pump chamber 25. In this embodiment, the intake passage 61 is connected to the pump chamber 25 via the intake port 28a. The intake passage 61 has a first intake passage section 61a, a second intake passage section 61b, and a third intake passage section 61c.

The first intake passage section 61a is a portion that extends from the intake opening 60a. In this embodiment, the first intake passage section 61a extends forward from the intake opening 60a. The second intake passage section 61b is a portion that extends in a curved manner from the first intake passage section 61a. In this embodiment, the second intake passage section 61b extends in a left-right direction that is perpendicular to the front-rear direction in which the first intake passage section 61a extends. The second intake passage section 61b extends, for example, from the front end of the first intake passage section 61a to the left. As shown in FIG. 3, the inner diameter of the second intake passage section 61b increases, for example, toward the left.

The third intake passage section 61c is a portion that bends and extends from the second intake passage section 61b. In this embodiment, the third intake passage section 61c extends in a front-rear direction perpendicular to the left-right direction in which the second intake passage section 61b extends. The third intake passage section 61c extends, for example, from the left end of the second intake passage section 61b to the front. The front end of the third intake passage section 61c is connected to the intake port 28a. The third intake passage section 61c is formed, for example, by blocking the rear opening of a hole that extends from the rear surface of the housing main body 21 toward the front with a plug member 94. The hole is formed, for example, by drilling using a drill or the like.

As shown in FIG. 4, the discharge flow path 62 is connected to the pump chamber 25. In this embodiment, the discharge flow path 62 is connected to the pump chamber 25 via the discharge port 28b. In this embodiment, the discharge flow path 62 extends in the front-rear direction from the discharge port 28b to the discharge opening 60b. As shown in FIG. 2 and FIG. 5, the discharge flow path 62 is located, for example, above the suction flow path 61. The discharge flow path 62 is located, for example, above the third suction flow path section 61c.

The relief flow path 63 extends from the discharge flow path 62 to the intake flow path 61. As shown in FIG. 5, the relief flow path 63 has a first relief flow path portion 63a and a second relief flow path portion 63b. The first relief flow path portion 63a is a portion extending from the discharge flow path 62. The first relief flow path portion 63a extends, for example, in the left-right direction. As shown in FIG. 4, the first relief flow path portion 63a extends, for example, from a portion of the discharge flow path 62 closer to the rear side to the right. The inner diameter of the first relief flow path portion 63a increases, for example, toward the right. As shown in FIG. 5, the first relief flow path portion 63a is, for example, located above the second intake flow path portion 61b. The left-right dimension of the first relief flow path portion 63a is, for example, larger than the left-right dimension of the second intake flow path portion 61b.

The second relief flow passage portion 63b is a portion that extends from the first relief flow passage portion 63a to the intake flow passage 61. In this embodiment, the second relief flow passage portion 63b is connected to a connection portion 61d of the intake flow passage 61 between the first intake flow passage portion 61a and the second intake flow passage portion 61b. In this embodiment, the second relief flow passage portion 63b has a first portion 63c and a second portion 63d.

The first portion 63c is a portion that extends from the first relief flow path portion 63a. The first portion 63c extends, for example, in the vertical direction. The first portion 63c extends, for example, downward from the right end of the first relief flow path portion 63a. In other words, in this embodiment, the first portion 63c extends from the first relief flow path portion 63a, bending in the vertical direction perpendicular to the left-right direction in which the first relief flow path portion 63a extends.

The second portion 63d is a portion that bends and extends from the first portion 63c and connects to the intake passage 61. The second portion 63d extends, for example, in the left-right direction. That is, the second portion 63d extends in the left-right direction perpendicular to the up-down direction in which the first portion 63c extends. The second portion 63d extends in the same direction as the second intake passage section 61b extends. The second portion 63d extends, for example, from the lower end of the first portion 63c to the left side. The second portion 63d is located, for example, below the right portion of the first relief passage section 63a. As shown in FIG. 3, the inner diameter of the second portion 63d is, for example, smaller than the inner diameter of the second intake passage section 61b. The inner diameter of the second portion 63d increases, for example, toward the left side.

The left end of the second portion 63d is connected to the connection portion 61d between the first intake passage portion 61a and the second intake passage portion 61b. Thus, in this embodiment, the second portion 63d of the second relief passage portion 63b that is connected to the intake passage 61 extends in the same direction as the second intake passage portion 61b, and is connected to the connection portion 61d of the intake passage 61 between the first intake passage portion 61a and the second intake passage portion 61b.

As shown in FIG. 3, the left-right dimension of the second portion 63d is, for example, larger than the front-rear dimension of the first intake passage portion 61a and the left-right dimension of the second intake passage portion 61b. As shown in FIG. 5, the left-right dimension of the second portion 63d is, for example, smaller than the left-right dimension of the first relief passage portion 63a.

As shown in Figures 2 and 3, the housing 20 has a first recess 64 that extends from a connection portion 61e between the second intake passage portion 61b and the third intake passage portion 61c in the same left-right direction as the second intake passage portion 61b extends. The first recess 64 is a recess that is recessed to the left from the connection portion 61e. The left portion of the first recess 64 is provided in, for example, the protrusion 21b. The first recess 64 is, for example, circular when viewed in the left-right direction.

As shown in FIG. 3, the inner diameter of the first recess 64 is, for example, larger than the inner diameter of the second intake passage portion 61b. The inner diameter of the first recess 64 increases, for example, toward the left. The left-right dimension of the first recess 64 is, for example, larger than the left-right dimension of the second portion 63d.

The first recess 64, the second intake passage section 61b, and the second portion 63d are connected in this order from the left side to the right side and are arranged on the same straight line. The first recess 64, the second intake passage section 61b, and the second portion 63d are formed by, for example, a single hole 66 that extends from the left side surface of the protrusion 21b to the right side.

The hole 66 is, for example, a circular hole with a bottom on the right side. The hole 66 is made, for example, when the housing body 21 is molded by die casting, by positioning part of the mold in the part that will become the hole 66. The inner diameter of the hole 66 increases from the right side to the left side. This makes it easier to remove part of the mold from inside the hole 66 to the left side after the housing body 21 is molded by die casting. The left end of the hole 66 is blocked by a plug member 93. This forms a first recess 64 that is recessed to the left from the connection part 61e. The hole 66 may also be made by hole processing using a drill or the like.

As shown in FIG. 5, the housing 20 has a second recess 65 that extends from a connection portion 63e between the first portion 63c and the second portion 63d in the same vertical direction as the first portion 63c extends. The second recess 65 is a recess that is recessed downward from the connection portion 63e. The second recess 65 and the first portion 63c are connected in this order from the bottom to the top, and are arranged on the same straight line. The second recess 65 and the first portion 63c are formed, for example, by a single hole 67 that extends upward from the lower surface of the housing main body 21.

The hole 67 is, for example, a circular hole with a bottom on the upper side. The hole 67 is made, for example, by drilling from the lower surface of the die-cast housing body 21 toward the upper side. The lower end of the hole 67 is blocked by a plug member 92. This forms a second recess 65 that is recessed downward from the connection portion 63e. The hole 67 may also be made by positioning part of a mold in the part that will become the hole 67 when the housing body 21 is die-cast.

As shown in FIG. 4, the housing 20 has a third recess 69. The third recess 69 is recessed to the left of the portion of the discharge flow path 62 where the first relief flow path portion 63a is connected. The direction in which the third recess 69 is recessed is opposite the direction in which the first relief flow path portion 63a extends from the discharge flow path 62. The third recess 69 is located on the opposite side of the discharge flow path 62 from the first relief flow path portion 63a, sandwiching the discharge flow path 62 in the left-right direction.

The relief valve 70 is provided in the relief flow path 63. In this embodiment, the relief valve 70 is provided in the first relief flow path portion 63a. The relief valve 70 can switch between a state in which the first relief flow path portion 63a and the second relief flow path portion 63b are connected to each other, and a state in which the first relief flow path portion 63a and the second relief flow path portion 63b are blocked from each other. The relief valve 70 shown in Figures 2, 4, and 5 is, for example, in a state in which the first relief flow path portion 63a and the second relief flow path portion 63b are blocked from each other.

In this embodiment, the relief valve 70 is a spool valve. As shown in FIG. 4, the relief valve 70 has a valve body 71 and an elastic member 72. The valve body 71 is, for example, cylindrical and extends in the left-right direction. The valve body 71 is fitted into a spool hole 73 that extends in the left-right direction so as to be movable in the left-right direction. The spool hole 73 is connected to the right side of the first relief flow passage portion 63a.

The spool hole 73, the first relief flow passage portion 63a, and the third recess 69 are arranged on the same straight line in this order from the right side to the left side. The spool hole 73, the first relief flow passage portion 63a, and the third recess 69 are formed, for example, by a single hole 68 extending from the right side surface of the housing body 21 to the left side.

The hole 68 is, for example, a circular hole with a bottom on the left side. The hole 68 is made, for example, when the housing body 21 is molded by die casting, by positioning part of the mold in the part that will become the hole 68. The inner diameter of the hole 68 increases from the left side to the right side. This makes it easier to remove part of the mold from inside the hole 68 to the right side after the housing body 21 is molded by die casting. The right end of the hole 68 is blocked by a plug member 91. This blocks the right end of the spool hole 73. The hole 68 may also be made by hole machining using a drill or the like.

The plug member 91 is, for example, a screw member. The plug member 91 has a screw body 91a and a screw head 91b. The screw body 91a is, for example, cylindrical, extending in the left-right direction and opening to the left. The screw body 91a is fastened and fixed to a female screw portion (not shown) provided on the inner peripheral surface of the right end of the spool hole 73. The screw head 91b extends radially outward from the right end of the screw body 91a. An annular seal member 95 is provided between the left surface of the screw head 91b and the right surface of the housing body 21, surrounding the screw body 91a.

The valve body 71 has a partition wall 71c that divides the cylindrical interior of the valve body 71 in the left-right direction. The part of the interior of the valve body 71 located to the left of the partition wall 71c opens, for example, to the left and is connected to the interior of the first relief flow path portion 63a. The part of the interior of the valve body 71 located to the right of the partition wall 71c opens, for example, to the right and is blocked from the interior of the first relief flow path portion 63a. In this embodiment, when the part of the interior of the valve body 71 located to the right of the partition wall 71c is located to the left of the first portion 63c of the second relief flow path portion 63b, the first relief flow path portion 63a and the second relief flow path portion 63b are blocked by the partition wall 71c.

The valve body 71 has a connection hole 71a and an air hole 71b. The connection hole 71a is provided in a portion of the valve body 71 located to the left of the partition wall portion 71c. The connection hole 71a is, for example, a circular hole that penetrates the valve body 71 in the radial direction from the inner peripheral surface to the outer peripheral surface. Although not shown in the figure, a plurality of connection holes 71a are provided, for example, along the circumferential direction around the valve body 71.

Air hole 71b is provided in a portion of valve body 71 located to the right of partition wall 71c. Air hole 71b is, for example, a circular hole that penetrates radially from the inner peripheral surface to the outer peripheral surface of valve body 71. Although not shown in the figure, multiple air holes 71b are provided, for example, along the circumferential direction around valve body 71.

The elastic member 72 is a member that applies an elastic force to the valve body 71 in the leftward direction. The elastic member 72 is, for example, a coil spring that extends in the left-right direction. The right side of the elastic member 72 is housed inside the screw body portion 91a of the plug member 91. The elastic member 72 is supported from the right side by the plug member 91. The left side of the elastic member 72 is housed inside the valve body 71 in a portion located to the right of the partition wall portion 71c. The left end of the elastic member 72 is in contact with the valve body 71. The elastic member 72 is in a state of being compressed and elastically deformed in the left-right direction. For example, the elastic member 72 presses the valve body 71 from the right side to the step portion provided on the inner circumferential surface of the first relief flow path portion 63a.

When the pressure of the oil O in the discharge flow passage 62 exceeds a predetermined value, the pressure applied to the right side of the partition wall portion 71c from the oil O flowing from the discharge flow passage 62 into the first relief flow passage portion 63a increases, and the valve body 71 moves to the right from the position shown in FIG. 4 against the elastic force of the elastic member 72. When the valve body 71 moves to the right and the connection hole 71a is in a position where it is connected to the first part 63c of the second relief flow passage portion 63b, the first relief flow passage portion 63a and the second relief flow passage portion 63b are connected through the part of the inside of the valve body 71 located to the left of the partition wall portion 71c and the connection hole 71a. As a result, a part of the oil O in the discharge flow passage 62 flows into the intake flow passage 61 through the first relief flow passage portion 63a and the second relief flow passage portion 63b.

When a portion of the oil O in the discharge flow passage 62 is discharged into the suction flow passage 61 through the relief flow passage 63, the pressure of the oil O in the discharge flow passage 62 decreases. As a result, when the pressure applied to the right side of the partition wall portion 71c from the oil O flowing into the first relief flow passage portion 63a decreases, the valve body 71 moves to the left again by the elastic member 72, and the first relief flow passage portion 63a and the second relief flow passage portion 63b are blocked by the valve body 71. As described above, the relief valve 70 opens and closes depending on the pressure of the oil O in the discharge flow passage 62. This makes it possible to prevent the pressure of the oil O in the discharge flow passage 62 from becoming excessively high.

In this embodiment, the air hole 71b is connected to the first portion 63c regardless of which position the valve body 71 is in in the left-right direction. Therefore, even if the valve body 71 moves to the right of the position shown in FIG. 4 and the volume of the part of the inside of the spool hole 73 located to the right of the partition wall portion 71c becomes smaller, the air in the spool hole 73 can be released to the second relief flow path portion 63b through the air hole 71b. Also, even if the valve body 71 moves to the left from the position where the connection hole 71a is connected to the second relief flow path portion 63b and the volume of the part of the inside of the spool hole 73 located to the right of the partition wall portion 71c becomes larger, air can be allowed to flow from the second relief flow path portion 63b into the spool hole 73 through the air hole 71b. As a result, it is possible to suppress fluctuations in the pressure in the part of the inside of the spool hole 73 located to the right of the partition wall portion 71c, and to suppress obstruction of the left-right movement of the valve body 71.

As shown in FIG. 1, the motor unit 30 has a rotor 31, a stator 32, and bearings 33 and 34. The rotor 31 is rotatable around a central axis J. In this embodiment, the central axis J is a virtual axis extending in the left-right direction. In other words, in this embodiment, the axial direction of the motor unit 30 is the left-right direction.

The rotor 31 has a cylindrical shaft 31a extending in the left-right direction around the central axis J, and a rotor body 31b fixed to the outer circumferential surface of the shaft 31a. The shaft 31a is supported by bearings 33 and 34 so as to be rotatable around the central axis J. The shaft 31a extends from inside the motor housing 24 through the connection hole 26 to inside the pump chamber 25. Although not shown, the rotor body 31b has an annular rotor core surrounding the shaft 31a and a magnet held by the rotor core.

The stator 32 faces the rotor 31 in the radial direction with a gap therebetween. The stator 32 is located radially outside the rotor 31. The stator 32 has a stator core 32a, an insulator 32b, and multiple coils 32c. The stator core 32a is annular and surrounds the rotor 31 around the central axis J. The outer peripheral surface of the stator core 32a is fixed to the inner peripheral surface of the motor housing 24. The multiple coils 32c are attached to the stator core 32a via the insulator 32b.

The bearings 33 and 34 are, for example, ball bearings. The bearing 33 supports the portion of the shaft 31a located to the right of the rotor body 31b so that it can rotate around the central axis J. The bearing 33, for example, supports the right end of the shaft 31a so that it can rotate. The bearing 33 is held, for example, by the first cover 22. The bearing 34 supports the portion of the shaft 31a located to the left of the rotor body 31b so that it can rotate around the central axis J. The bearing 34 is fitted and held within the bearing holder 24a.

The pump mechanism 40 is housed in the pump chamber 25. The pump mechanism 40 is connected to the motor unit 30. The pump mechanism 40 is connected to a portion of the shaft 31a that is located in the pump chamber 25. The pump mechanism 40 is connected, for example, to the left end of the shaft 31a. The pump mechanism 40 is, for example, a trochoid type pump mechanism. The pump mechanism 40 has an inner rotor 41 and an outer rotor 42.

The inner rotor 41 is connected to the shaft 31a. The inner rotor 41 rotates about the central axis J as the shaft 31a rotates about the central axis J. Although not shown in the figure, the inner rotor 41 has multiple teeth on its outer circumferential surface.

The outer rotor 42 is annular and surrounds the inner rotor 41 around the central axis J. Although not shown, the outer rotor 42 has a number of teeth on its inner circumferential surface that mesh with the teeth of the inner rotor 41. The outer rotor 42 rotates when the inner rotor 41 is rotated by the shaft 31a. The rotation axis of the outer rotor 42 extends in the left-right direction and is radially eccentric with respect to the central axis J.

The control device 50 is attached to the housing 20. The control device 50 is located, for example, on the lower side of the housing 20. The control device 50 has, for example, a circuit board 51. Although not shown in the figure, the circuit board 51 is provided with, for example, an inverter that controls the power supplied to the motor unit 30.

The busbar assembly 80 is housed in the motor housing 24. The busbar assembly 80 is located to the right of the stator 32. The busbar assembly 80 has a busbar holder 81 and a busbar 82. The busbar holder 81 is a resin member that holds the busbar 82. The busbar 82 electrically connects the coil 32c and the circuit board 51.

When power is supplied to the coil 32c from the inverter (not shown) of the circuit board 51 via the bus bar 82, the rotor 31 rotates, and the inner rotor 41 and the outer rotor 42 rotate. As a result, as shown in FIG. 2, oil O is sucked into the suction passage 61 from outside the electric pump 10 through the suction opening 60a. The oil O sucked into the suction passage 61 flows through the first suction passage portion 61a, the second suction passage portion 61b, and the third suction passage portion 61c in this order, and is sucked into the pump chamber 25 from the suction port 28a. The oil O sucked into the pump chamber 25 flows into the gap between the teeth of the inner rotor 41 and the teeth of the outer rotor 42, and is sent around the central axis J inside the pump chamber 25. The oil O sent around the central axis J inside the pump chamber 25 is discharged to the discharge passage 62 through the discharge port 28b. The oil O discharged into the discharge passage 62 is discharged from the discharge opening 60b to the outside of the electric pump 10.

Here, when the pressure of the oil O discharged from the pump chamber 25 into the discharge passage 62 is equal to or greater than a predetermined value, the relief valve 70 opens as described above, and the first relief passage portion 63a and the second relief passage portion 63b are connected. Therefore, in this case, a portion of the oil O discharged into the discharge passage 62 is returned into the intake passage 61 via the relief passage 63. The oil O returned from the relief passage 63 into the intake passage 61 is again sucked into the pump chamber 25.

For example, when part of the oil O in the discharge flow passage 62 is returned directly to the pump chamber 25, and when part of the oil O in the discharge flow passage 62 is returned to the pump chamber 25 from a portion of the suction flow passage 61 that is relatively close to the pump chamber 25, the pressure of the oil O in the pump chamber 25 may increase due to the oil O returned from the discharge flow passage 62 to the pump chamber 25, and the pressure of the oil O discharged from the pump chamber 25 to the discharge flow passage 62 may become large. Therefore, the pressure of the oil O discharged from the pump chamber 25 into the discharge flow passage 62 may vary depending on whether the oil O is returned from the discharge flow passage 62 to the pump chamber 25 or not, and the pressure of the oil O discharged from the discharge flow passage 62 may pulsate.

In contrast, according to this embodiment, the intake passage 61 has a first intake passage portion 61a extending from the intake opening 60a and a second intake passage portion 61b extending in a bent manner from the first intake passage portion 61a. The relief passage 63 has a first relief passage portion 63a extending from the discharge passage 62 and a second relief passage portion 63b extending from the first relief passage portion 63a to the intake passage 61. The second relief passage portion 63b is connected to a connection portion 61d between the first intake passage portion 61a and the second intake passage portion 61b of the intake passage 61. Therefore, the position where the oil O from the relief passage 63 flows into the intake passage 61 can be made farther from the pump chamber 25 than when the second relief passage portion 63b is connected to a portion of the intake passage 61 downstream of the connection portion 61d, when it is connected to the intake port 28a, and when it is connected to the pump chamber 25. This makes it easier to stabilize the pressure of the oil O in the intake passage 61 from when the oil O from the relief passage 63 joins with the oil O in the intake passage 61 until it flows into the pump chamber 25. This makes it possible to prevent the oil O in the pump chamber 25 from being affected by the oil O from the relief passage 63 that joins with the oil O in the intake passage 61. Therefore, even if a portion of the oil O in the discharge passage 62 is returned to the pump chamber 25 via the relief passage 63, it is possible to prevent the pressure of the oil O discharged from the pump chamber 25 to the discharge passage 62 from fluctuating. This makes it possible to suppress pressure pulsation of the oil O discharged from the discharge passage 62.

In addition, according to this embodiment, the portion of the second relief flow passage portion 63b that is connected to the intake flow passage 61, i.e., the second portion 63d, extends in the same direction as the second intake flow passage portion 61b and is connected to the connection portion 61d of the intake flow passage 61 between the first intake flow passage portion 61a and the second intake flow passage portion 61b. Therefore, the second portion 63d and the second intake flow passage portion 61b can be arranged to be connected on the same straight line. As a result, by creating the hole 66 as described above, both the second intake flow passage portion 61b and the second portion 63d that is part of the second relief flow passage portion 63b can be easily created. Therefore, the intake flow passage 61 and the relief flow passage 63 can be easily created.

In addition, according to this embodiment, the intake passage 61 has a third intake passage section 61c that extends in a bent manner from the second intake passage section 61b. Therefore, after the oil O from the relief passage 63 merges with the oil O in the intake passage 61, the flow direction of the oil O in the intake passage 61 changes to a direction bent between the second intake passage section 61b and the third intake passage section 61c. As a result, the flow momentum of the oil O flowing into the pump chamber 25 is more easily attenuated than when the oil O from the relief passage 63 flows in one direction in the intake passage 61 and flows into the pump chamber 25. Therefore, the oil O from the relief passage 63 is less likely to affect the oil O in the pump chamber 25 than when the oil O from the relief passage 63 flows in one direction in the intake passage 61 and flows into the pump chamber 25. Therefore, the pressure of the oil O discharged from the pump chamber 25 to the discharge passage 62 can be more effectively suppressed from fluctuating. As a result, the pressure pulsation of the oil O discharged from the discharge passage 62 can be more effectively suppressed.

According to this embodiment, the housing 20 has a first recess 64 extending from the connection portion 61e between the second intake passage portion 61b and the third intake passage portion 61c in the same direction as the direction in which the second intake passage portion 61b extends. Therefore, the oil O flows from the second intake passage portion 61b into the first recess 64, and the oil O is stored in the first recess 64. As a result, the oil O flowing to the left in the second intake passage portion 61b can be received by the oil O stored in the first recess 64. Therefore, when the oil O flows from the second intake passage portion 61b to the third intake passage portion 61c, a part of the kinetic energy of the oil O can be absorbed by the oil O stored in the first recess 64. Therefore, it is easier to attenuate the flow momentum of the oil O in the intake passage 61 after it joins the relief passage 63. This makes it possible to more effectively suppress the oil O that joins the intake passage 61 from the relief passage 63 from affecting the pressure of the oil O in the pump chamber 25. Therefore, fluctuations in the pressure of the oil O discharged from the pump chamber 25 to the discharge passage 62 can be further suppressed. Therefore, pulsation of the pressure of the oil O discharged from the discharge passage 62 can be further suppressed.

In addition, according to this embodiment, the third intake passage section 61c extends in a direction perpendicular to the direction in which the second intake passage section 61b extends. Therefore, the angle at which the third intake passage section 61c bends with respect to the second intake passage section 61b can be made larger to a certain extent. This makes it easier to attenuate the flow momentum of the oil O when it flows from the second intake passage section 61b to the third intake passage section 61c, and more effectively suppresses the influence on the pressure of the oil O in the pump chamber 25. Therefore, it is more effectively suppressed that the pressure of the oil O discharged from the pump chamber 25 to the discharge passage 62 fluctuates. Therefore, it is more effectively suppressed that the pulsation of the pressure of the oil O discharged from the discharge passage 62. Also, compared to the case where the angle at which the third intake passage section 61c bends with respect to the second intake passage section 61b is larger than 90°, it is easier to flow the oil O from the second intake passage section 61b to the third intake passage section 61c.

The angle at which the third intake passage section 61c bends relative to the second intake passage section 61b corresponds to the magnitude of the angle change in the flow direction of the oil O when it flows from the second intake passage section 61b to the third intake passage section 61c. In other words, the larger the angle at which the third intake passage section 61c bends relative to the second intake passage section 61b, the larger the angle change in the flow direction of the oil O when it flows from the second intake passage section 61b to the third intake passage section 61c. Also, the smaller the angle at which the third intake passage section 61c bends relative to the second intake passage section 61b, the smaller the angle change in the flow direction of the oil O when it flows from the second intake passage section 61b to the third intake passage section 61c. In this embodiment, the angle at which the third intake passage section 61c bends relative to the second intake passage section 61b is the angle φ shown in FIG. 3. The angle φ is an angle that indicates the degree to which the third intake passage section 61c is tilted forward relative to the extension of the second intake passage section 61b when the second intake passage section 61b is extended to the left. In this embodiment, the angle φ is also the angle between the first recess 64 and the third intake passage section 61c.

According to this embodiment, the second relief flow path portion 63b has a first portion 63c extending from the first relief flow path portion 63a, and a second portion 63d extending from the first portion 63c in a bent manner and connected to the intake flow path 61. Therefore, the flow direction of the oil O in the second relief flow path portion 63b changes to a bent direction between the first portion 63c and the second portion 63d. As a result, the flow momentum of the oil O in the second relief flow path portion 63b can be attenuated compared to the case where the oil O flows in one direction in the second relief flow path portion 63b and merges with the oil O in the intake flow path 61. Therefore, it is possible to more effectively prevent the oil O returned from the second relief flow path portion 63b to the intake flow path 61 from affecting the oil O in the pump chamber 25. Therefore, it is possible to more effectively prevent the pressure of the oil O discharged from the pump chamber 25 to the discharge flow path 62 from fluctuating. As a result, it is possible to more effectively prevent the pressure pulsation of the oil O discharged from the discharge flow path 62.

According to this embodiment, the housing 20 has a second recess 65 extending from the connection portion 63e between the first portion 63c and the second portion 63d in the same direction as the first portion 63c extends. Therefore, the oil O flows from the first portion 63c into the second recess 65, and the oil O is stored in the second recess 65. As a result, the oil O flowing downward in the first portion 63c can be received by the oil O stored in the second recess 65. Therefore, when flowing from the first portion 63c to the second portion 63d, part of the kinetic energy of the oil O can be absorbed by the oil O stored in the second recess 65. Therefore, it is easy to attenuate the flow momentum of the oil O that merges from the relief flow path 63 to the suction flow path 61. This makes it possible to further suppress the oil O that merges from the relief flow path 63 to the suction flow path 61 from affecting the pressure of the oil O in the pump chamber 25. Therefore, fluctuations in the pressure of the oil O discharged from the pump chamber 25 to the discharge passage 62 can be further suppressed. Therefore, pulsation of the pressure of the oil O discharged from the discharge passage 62 can be further suppressed.

In addition, according to this embodiment, the first portion 63c is bent and extends from the first relief flow passage portion 63a in a direction perpendicular to the direction in which the first relief flow passage portion 63a extends. The second portion 63d extends in a direction perpendicular to the direction in which the first portion 63c extends. Therefore, the oil O flowing through the relief flow passage 63 flows while bending at a right angle at least twice between the discharge flow passage 62 and the suction flow passage 61. This makes it easy to preferably attenuate the flow momentum of the oil O in the relief flow passage 63. Therefore, it is possible to more effectively suppress the oil O that merges from the relief flow passage 63 to the suction flow passage 61 from affecting the pressure of the oil O in the pump chamber 25. Therefore, it is possible to more effectively suppress the pressure of the oil O discharged from the pump chamber 25 to the discharge flow passage 62 from fluctuating. This makes it possible to more effectively suppress the pulsation of the pressure of the oil O discharged from the discharge flow passage 62. In addition, it is easier to allow oil O to flow through the relief flow passage 63 to a certain extent, compared to when the flow direction of oil O changes by more than 90° within the relief flow passage 63.

In addition, according to this embodiment, the relief valve 70 is provided in the first relief flow passage portion 63a. Therefore, compared to when the relief valve 70 is provided in the second relief flow passage portion 63b, it is easier to shorten the length of the portion of the relief flow passage 63 that is connected to the discharge flow passage 62 when the first relief flow passage portion 63a and the second relief flow passage portion 63b are blocked. This makes it possible to shorten the time until the discharge flow passage 62 is filled with oil O, for example, when the electric pump 10 is operated for the first time. Therefore, it is possible to shorten the time until the oil O starts to be discharged from the discharge opening portion 60b. Therefore, the responsiveness of the electric pump 10 can be improved. In addition, since it is easy to shorten the distance from the discharge flow passage 62 to the relief valve 70, the responsiveness of the relief valve 70 can also be improved. In addition, when the relief valve 70 is provided with a spool hole 73 as a spool valve as in this embodiment, a configuration can be adopted in which the spool hole 73 is connected to the first relief flow passage portion 63a in the same straight line. Therefore, by creating the hole 68 as described above, it is possible to easily create both the first relief flow passage portion 63a and the spool hole 73. Therefore, it is possible to create the relief flow passage 63 and also to create a location for placing the relief valve 70. This makes it easy to manufacture the electric pump 10.

In addition, by arranging the relief valve 70 by connecting the spool hole 73 to the right side of the first relief flow passage portion 63a, it is easy to arrange the first part 63c of the second relief flow passage portion 63b extending downward from the first relief flow passage portion 63a on the right side. This makes it easy to arrange the right end of the second part 63d extending from the first part 63c to the connection part 61d away from the connection part 61d to the right side. Therefore, it is easy to increase the dimension of the second part 63d in the left-right direction, and it is easy to attenuate the flow of oil O flowing toward the intake flow passage 61 in the second part 63d. Therefore, even if the oil O merges from the relief flow passage 63 to the intake flow passage 61, it is possible to more effectively suppress the influence on the pressure of the oil O in the pump chamber 25. This makes it possible to more effectively suppress the fluctuation of the pressure of the oil O discharged from the pump chamber 25 to the discharge flow passage 62. Therefore, it is possible to more effectively suppress the pulsation of the pressure of the oil O discharged from the discharge flow passage 62. In addition, by arranging the relief valve 70 by connecting the spool hole 73 to the right side of the first relief flow passage portion 63a, the electric pump 10 can be prevented from becoming larger in the vertical direction compared to, for example, a case in which the relief valve 70 is arranged in the first part 63c of the second relief flow passage portion 63b.

The present invention is not limited to the above-described embodiment, and the following other configurations and methods may be adopted within the scope of the technical concept of the present invention.

The first relief flow path portion may have any configuration as long as it extends from the discharge flow path and connects to the second relief flow path portion. The first relief flow path portion may extend in any direction. The first relief flow path portion may have one or more bent portions. In this case, the angle at which the first relief flow path portion bends may be less than 90° or may be greater than 90°. The first relief flow path portion may be connected to any point in the discharge flow path.

The second relief flow passage portion may be connected to the first intake flow passage portion. For example, in the above-described embodiment, the second portion 63d may be located further rearward and connected to the first intake flow passage portion 61a from the right side. With this configuration, the position where the oil O from the relief flow passage 63 flows into the intake flow passage 61 can be made farther away from the pump chamber 25. Therefore, the oil O in the pump chamber 25 can be more effectively prevented from being affected by the oil O from the relief flow passage 63 that has merged with the oil O in the intake flow passage 61. This can more effectively prevent the pressure of the oil O discharged from the pump chamber 25 to the discharge flow passage 62 from fluctuating. This can more effectively prevent the pressure pulsation of the oil O discharged from the discharge flow passage 62.

The second relief flow path section may have any configuration as long as it is connected to the connection portion between the first and second intake flow path sections of the intake flow path or to the first intake flow path section. The second relief flow path section may extend in any direction. The second relief flow path section may have two or more bending portions. The bending angle of the second relief flow path section may be 90° or less or may be greater than 90°. The second relief flow path section may not have a bending portion. In this case, the second relief flow path section does not have a first portion and a second portion.

The intake flow path may have any configuration as long as it has a first intake flow path section and a second intake flow path section. The intake flow path may have three or more bent portions. The intake flow path may have only one bent portion. In this case, the intake flow path does not have a third intake flow path section. The angle at which the intake flow path bends may be less than 90° or greater than 90°.

The discharge flow path may have any configuration as long as it is connected to the pump chamber. The discharge flow path may have one or more bent portions. In this case, the angle at which the discharge flow path bends may be less than 90° or may be greater than 90°.

When each of the above-mentioned flow paths has two or more bent portions, the bending angle may be the same at all the portions or may be different depending on the portion. The first recess may not be provided. The second recess may not be provided.

The relief valve may have any structure as long as it can switch between a state in which the first relief flow passage section and the second relief flow passage section are connected to each other and a state in which the first relief flow passage section and the second relief flow passage section are blocked from each other. The relief valve may be a poppet type valve or a solenoid valve. The relief valve may be provided in the second relief flow passage section.

The use of the electric pump to which the present invention is applied is not particularly limited. The electric pump may be mounted on equipment other than a vehicle. The fluid pumped by the electric pump is not particularly limited and may be, for example, water.

The configurations and methods described above in this specification can be combined as appropriate within the limits of not being mutually inconsistent.

10...electric pump, 20...housing, 25...pump chamber, 30...motor section, 40...pump mechanism, 60a...suction opening, 61...suction passage, 61a...first suction passage section, 61b...second suction passage section, 61c...third suction passage section, 61d, 61e, 63e...connection section, 62...discharge passage, 63...relief passage, 63a...first relief passage section, 63b...second relief passage section, 63c...first section, 63d...second section, 64...first recess, 65...second recess, 70...relief valve

Claims (7)

A motor unit;
a pump mechanism coupled to the motor unit;
a housing including a pump chamber that accommodates the pump mechanism, a suction passage connected to the pump chamber, a discharge passage connected to the pump chamber, and a relief passage extending from the discharge passage to the suction passage;
a relief valve provided in the relief flow passage;
Equipped with
The housing has an intake opening that opens to the outside of the housing,
The intake passage is
a first intake passage portion extending from the intake opening portion;
a second intake passage portion extending in a bent manner from the first intake passage portion;
having
The relief flow path is
a first relief passage portion extending from the discharge passage and extending in an axial direction of the motor ;
a second relief passage portion extending from the first relief passage portion to the intake passage;
having
the relief valve extends in an axial direction of the motor, and is switchable between a state in which the first relief flow path portion and the second relief flow path portion are connected to each other and a state in which the first relief flow path portion and the second relief flow path portion are blocked from each other,
The second relief passage portion is connected to a connection portion between the first intake passage portion and the second intake passage portion of the intake passage or to the first intake passage portion,
The second relief flow path portion is
a first portion extending in a radial direction of the motor from the first relief flow passage portion;
a second portion that is bent from the first portion, extends in the axial direction of the motor, and is connected to the intake passage;
having
The first relief channel portion is longer than the first portion.
Electric pump. The electric pump according to claim 1, wherein the portion of the second relief passage portion that is connected to the intake passage extends in the same direction as the second intake passage portion and is connected to the connection portion of the intake passage between the first intake passage portion and the second intake passage portion. The electric pump according to claim 1 or 2, wherein the intake passage has a third intake passage portion that bends and extends from the second intake passage portion. The electric pump according to claim 3, wherein the housing has a first recess extending from a connection between the second intake passage portion and the third intake passage portion in the same direction as the second intake passage portion extends. The electric pump according to claim 3 or 4, wherein the third intake passage portion extends in a direction perpendicular to the direction in which the second intake passage portion extends. The electric pump according to claim 1 , wherein the housing has a second recess extending from a connection portion between the first portion and the second portion in the same direction as the extension direction of the first portion. The electric pump according to claim 1 , wherein the relief valve is provided in the first relief flow passage portion.

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