Relief valve, pump device, and electric pump

Abstract

To provide a relief valve with light weight and small manufacturing manhours.SOLUTION: A relief valve comprises: a valve body reciprocatably housed in a relief flow path; a coil spring housed on a side opposite to an emission flow path across the valve body of the relief flow path and contacting the valve body at a tip; a housing where a base end opening for causing the valve body and the coil spring to enter the relief flow path by opening an end opposite to the emission flow path of the relief flow path to the outside, an annular space enlarged outward in a radial direction from the relief flow path and continued in a circumferential direction between a discharge port and the base end opening, and an insertion opening for opening a part of the circumferential direction of the annular space to the outside are formed; and a base end plate housed across the relief flow path and the annular space through the insertion opening and contacting a base end of the coil spring, so as to cause the coil spring to urge the valve body toward the emission flow path.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a relief valve, a pump device, and an electric pump. [Background technology]

[0002] In recent years, efforts have been made to promote the Sustainable Development Goals (2030 Agenda for Sustainable Development, adopted at the United Nations Summit on September 25, 2015, hereafter referred to as "SDGs"). In line with this, technologies that aim to prevent waste generation, reduce waste, and significantly reduce waste generation by recycling and reusing products in order to ensure sustainable production and consumption patterns have become known.

[0003] Conventionally, there has been known a relief valve that adjusts the discharge pressure of a liquid (e.g., oil) compressed by a pump. The relief valve includes a housing in which a relief flow passage connected to a discharge flow passage is formed, a valve body accommodated in the relief flow passage so as to be capable of reciprocating motion, and a coil spring that biases the valve body toward the discharge flow passage (see, for example, Patent Document 1).

[0004] In the relief valve described in Patent Document 1, the base end of the relief flow passage is opened in order to accommodate the valve body and the coil spring in the relief flow passage. In addition, after the valve body and the coil spring are accommodated in the relief flow passage, a relief plate that closes the base end opening of the relief flow passage is screwed to the housing of the relief valve. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-008844 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the relief valve of Patent Document 1 has a first problem in that the weight increases by the amount of the relief plate and the screws for closing the base end opening, and a second problem in that the manufacturing man-hours (takt time) increase by the amount of the screws for fastening the relief plate to the housing.

[0007] An object of the present invention is to provide a relief valve that is lightweight and requires fewer manufacturing steps. [Means for solving the problem]

[0008] In order to achieve the above object, the present invention provides a relief valve including a housing having a relief flow passage connected to a discharge flow passage that discharges liquid compressed by a pump and extending linearly, and a discharge port that opens a part of a side surface of the relief flow passage to the outside and discharges liquid that has flowed into the relief flow passage from the discharge flow passage to the outside, a valve body that is accommodated in the relief flow passage so as to be able to reciprocate, and a coil spring that is accommodated on the side of the relief flow passage opposite the discharge flow passage with the valve body therebetween and whose tip abuts against the valve body, The relief flow passage has a base end opening that opens the end opposite the flow passage to the outside, allowing the valve body and the coil spring to enter the relief flow passage, and between the discharge port and the base end opening, an annular space that extends radially outward from the relief flow passage and is continuous in the circumferential direction, and an insertion opening that opens a circumferential portion of the annular space to the outside are formed, and the relief flow passage further includes a base end plate that is accommodated across the relief flow passage and the annular space through the insertion opening and abuts against the base end of the coil spring, causing the coil spring to urge the valve body toward the discharge flow passage. Effect of the Invention

[0009] According to the present invention, it is possible to obtain a relief valve that is lightweight and requires few manufacturing steps. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is an external perspective view of the electric pump; [Diagram 2] FIG. 2 is an exploded perspective view of the pump unit according to the first embodiment, as viewed from the motor unit side. [Diagram 3] FIG. 2 is an exploded perspective view of the pump unit according to the first embodiment, as viewed from the opposite side to the motor unit. [Figure 4] 4 is a diagram showing a pump section in a state in which a coil spring is pressed by a pressing jig according to the first embodiment. FIG. [Diagram 5] FIG. 2 is a view showing a pump section in a state in which a base end plate according to the first embodiment is inserted. [Figure 6] 4 is a cross-sectional view of the pump portion after the pressing jig according to the first embodiment has been removed. FIG. [Figure 7] FIG. 11 is an exploded perspective view of a pump unit according to a second embodiment, as viewed from the motor unit side. [Figure 8] FIG. 11 is an exploded perspective view of a pump unit according to a second embodiment, as viewed from the opposite side to the motor unit. [Figure 9] 13 is a diagram showing a pump section in a state in which a coil spring is pressed by a pressing jig according to a second embodiment. FIG. [Figure 10] FIG. 11 is a view showing a pump section in a state in which a base end plate according to a second embodiment is inserted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] An electric pump 1 according to an embodiment of the present invention will now be described with reference to the drawings. FIG 1 is a perspective view of the electric pump 1 ...2 is a perspective view of the electric pump 1. FIG 3 is a perspective view of the electric pump 1. FIG 4 is a perspective view of the electric pump 1. FIG 5 is a perspective view of the electric pump 1. FIG 6 is a perspective

[0012] The electric pump 1 is a device that receives a supply of electric power to compress and discharge a liquid. The electric pump 1 is typically an oil pump device that supplies oil (e.g., lubricating oil) to an engine clutch or a transmission clutch mounted on an automobile. However, the use of the electric pump 1 is not limited to this. In addition, a specific example of the liquid is not limited to oil.

[0013] 1, the electric pump 1 includes a motor unit 2, a control unit 3, and a pump unit 4. The motor unit 2 and the control unit 3 are independent of the pump unit 4 and constitute a so-called "mechanically and electrically integrated" motor device 5. The pump unit 4 is independent of the motor unit 2 and the control unit 3 and constitutes a pump device.

[0014] The motor section 2 includes an electric motor 6 (see Figs. 4 to 6) that rotates (generates driving force) by driving power supplied from the control section 3. There is no particular limitation on the specific example of the electric motor 6, but for example, an inner rotor type brushless motor can be adopted. The configuration of the electric motor 6 is already well known, so a detailed description will be omitted. The control section 3 supplies power supplied from an external device (not shown) to the electric motor 6 as driving power. The driving force of the motor section 2 is transmitted to the pump section 4, which pumps oil.

[0015] The motor section 2, the control section 3, and the pump section 4 are disposed adjacent to each other in the extending direction of a rotating shaft 7 (see Figs. 4 to 6) of an electric motor 6, which will be described later. More specifically, the control section 3 is disposed adjacent to the motor section 2 disposed in the center on one side in the extending direction of the rotating shaft 7, and the pump section 4 is disposed adjacent to the other side in the extending direction of the rotating shaft 7.

[0016] The electric pump 1 includes a motor housing 8 that houses the components of the motor section 2 and the control section 3, and a pump housing 10 (housing) that houses the components of the pump section 4. The motor housing 8 and the pump housing 10 are made of a metal material such as aluminum die-cast. The electric pump 1 may include an integrated housing that houses the motor section 2, the control section 3, and the pump section 4 together.

[0017] [First embodiment] [Configuration of pump section 4] The pump section 4 according to the first embodiment will be described with reference to Figs. 2 to 6. Fig. 2 is an exploded perspective view of the pump section 4 according to the first embodiment, as viewed from the motor section 2 side. Fig. 3 is an exploded perspective view of the pump section 4 according to the first embodiment, as viewed from the opposite side to the motor section 2. Fig. 4 is a view showing the pump section 4 in a state in which the coil spring 13 is pressed by the pressing jig 33 according to the first embodiment. Fig. 5 is a view showing the pump section 4 in a state in which the base end plate 14 according to the first embodiment is inserted. Fig. 6 is a view showing the pump section 4 after the pressing jig 33 according to the first embodiment has been removed. As shown in Figs. 2 and 3, the pump section 4 includes a pump housing 10, a pump unit 11 (pump), a valve body 12, a coil spring 13, and a base end plate 14.

[0018] The pump housing 10 accommodates the components (11-14) of the pump section 4. The pump housing 10 is composed of a pump case 15 that accommodates the pump unit 11, and a pump cover 16 that accommodates the valve body 12, the coil spring 13, and the base end plate 14. The pump case 15 and the pump cover 16 are connected (fastened) by bolts 17a, 17b, 17c and a positioning pin (not shown).

[0019] The pump case 15 has a cylindrical outer shape with both ends open. The pump unit 11 is housed in the internal space of the pump case 15. One axial end of the pump case 15 is connected to the motor housing 8, and the other axial end is connected to the pump cover 16.

[0020] A suction passage 18, a discharge passage 19, and a relief passage 20 are formed inside the pump cover 16. The suction passage 18 and the discharge passage 19 are oil passages that penetrate the pump cover 16 generally in the axial direction of the rotating shaft 7. The suction passage 18 is a passage that supplies oil sucked in through a suction port 21 to the pump unit 11. The discharge passage 19 is a passage that discharges oil compressed by the pump unit 11 to the outside through a discharge port 22. The suction port 21 and the discharge port 22 are formed on the surface of the pump cover 16 opposite to the connection surface with the pump case 15.

[0021] The relief flow passage 20 is an oil flow passage connected to the discharge flow passage 19. In other words, the relief flow passage 20 is a flow passage branched from the discharge flow passage 19. The relief flow passage 20 is a flow passage extending linearly. The relief flow passage 20 is a cylindrical space. The relief flow passage 20 accommodates the valve body 12, the coil spring 13, and the base end plate 14. Hereinafter, of both ends in the extension direction of the relief flow passage 20, the end connected to the discharge flow passage 19 will be referred to as the "tip" and the end opposite to the tip will be referred to as the "base". The relief flow passage 20 includes a discharge port 23, a base end opening 24, an annular portion 25, an annular space 26, and an insertion opening 27.

[0022] The discharge port 23 is an opening provided on a side surface of the relief flow passage 20 between the tip end and base end of the relief flow passage 20. That is, the discharge port 23 opens a part of the side surface of the relief flow passage 20 to the outside of the pump cover 16. The discharge port 23 discharges the oil that has flowed from the discharge flow passage 19 into the relief flow passage 20 to the outside of the pump cover 16. The discharge port 23 can be formed on all surfaces of the pump cover 16, but in the first embodiment, for example, the discharge port 23 is formed on the same surface as the suction port 21 and the discharge port 22 of the pump cover 16.

[0023] The base end opening 24 is an opening provided at the base end of the relief flow passage 20. That is, the base end opening 24 opens the end of the relief flow passage 20 opposite the discharge flow passage 19 to the outside of the pump cover 16. In addition, the base end opening 24 is an opening for allowing the valve body 12, the coil spring 13, and a pressing jig 33 (described later) to enter the relief flow passage 20.

[0024] The annular portion 25 is provided between the tip of the relief passage 20 and the discharge port 23. The annular portion 25 refers to a tubular portion that protrudes radially inward from the inner surface of the relief passage 20 and continues in the circumferential direction. The annular portion 25 prevents the valve body 12 housed in the relief passage 20 from moving toward the discharge passage 19 beyond the annular portion 25. On the other hand, the annular portion 25 allows the oil that has flowed from the discharge passage 19 into the relief passage 20 to pass through.

[0025] The annular space 26 is a space provided between the outlet 23 and the base end opening 24 of the relief flow passage 20. The annular space 26 is a space that accommodates the base end plate 14. Furthermore, the annular space 26 is an annular space that expands radially outward from the relief flow passage 20 and is continuous in the circumferential direction. In other words, the annular space 26 is connected to the relief flow passage 20. Furthermore, the diameter (outer diameter dimension) of the annular space 26 is larger than the diameter of the relief flow passage 20. Therefore, a step is formed between the relief flow passage 20 and the annular space 26.

[0026] The insertion opening 27 is an opening that opens a circumferential portion of the annular space 26 to the outside of the pump cover 16. The insertion opening 27 is an opening for inserting the base end plate 14 into the annular space 26. That is, the base end plate 14 is inserted into the annular space 26 through the insertion opening 27 in a direction perpendicular to the extension direction of the relief flow passage 20. The insertion opening 27 can be formed on all surfaces of the pump cover 16, but in the first embodiment, for example, the insertion opening 27 is formed on the same surface as the suction port 21, the discharge port 22, and the exhaust port 23 of the pump cover 16.

[0027] The pump unit 11 compresses oil supplied through the intake passage 18 by transmitting the driving force of the motor section 2, and discharges the oil through the discharge passage 19. The pump unit 11 is, for example, a trochoid pump composed of an outer rotor 28 and an inner rotor 29 that rotates within the outer rotor 28. The inner rotor 29 is connected to the rotating shaft 7. The oil is compressed by the inner rotor 29 rotating in conjunction with the rotation of the rotating shaft 7. The configuration of the pump unit 11 is well known, so a detailed description thereof will be omitted.

[0028] The valve element 12 is accommodated in the relief flow passage 20 and reciprocates between the tip and base ends of the relief flow passage 20. More specifically, the valve element 12 is accommodated in the relief flow passage 20 through a base end opening 24 and reciprocates between an annular portion 25 and an annular space 26. The valve element 12 is composed of a valve body 30 and a guide rod 31.

[0029] The valve body 30 is a cylindrical part whose diameter is almost the same as the inner diameter dimension of the relief flow passage 20. That is, the valve body 30 liquid-tightly separates the internal space of the relief flow passage 20 into a space on the tip side of the valve body 30 and a space on the base end side of the valve body 30. That is, the oil that flows from the discharge flow passage 19 into the relief flow passage 20 does not reach the base end side of the relief flow passage 20 beyond the valve body 30. The guide rod 31 protrudes from the valve body 30 toward the base end side of the relief flow passage 20. The guide rod 31 guides the coil spring 13.

[0030] The coil spring 13 is accommodated in a space on the base end side of the valve body 30 in the relief flow passage 20. The coil spring 13 is accommodated in the relief flow passage 20 through a base end opening 24. The coil spring 13 is also fitted onto a guide rod 31. The tip of the coil spring 13 abuts against the valve body 12 (more specifically, the valve body 30). Meanwhile, the base end of the coil spring 13 abuts against the base end plate 14.

[0031] Of both axial end faces of the valve body 30, the tip face facing the tip side of the relief flow passage 20 is a pressure-receiving face that receives the pressure of the oil passing through the discharge flow passage 19. On the other hand, the base end face of the valve body 30 facing the base end side of the relief flow passage 20 is an abutment face with which the tip of the coil spring 13 abuts. In other words, the valve body 30 reciprocates within the relief flow passage 20 depending on the magnitude relationship between the oil pressure received at the pressure-receiving face and the biasing force of the coil spring 13 abutting on the abutment face.

[0032] The base end plate 14 is inserted into the annular space 26 through the insertion opening 27. The base end plate 14 is disposed across the relief flow passage 20 and the annular space 26. The base end plate 14 abuts against the base end of the coil spring 13. The base end plate 14 is engaged with a step between the relief flow passage 20 and the annular space 26 (more specifically, the step on the base end side of the relief flow passage 20), and movement of the base end plate 14 from the annular space 26 toward the base end side of the relief flow passage 20 is restricted.

[0033] Further, a notch 32 is formed in the base end plate 14. The notch 32 penetrates the base end plate 14 in the thickness direction and reaches a part of the outer edge of the base end plate 14. That is, a part of the outer edge of the base end plate 14 is opened by the notch 32. In this way, the base end plate 14 according to the first embodiment has a so-called "horseshoe shape". The notch 32 is formed with a size that allows a pressing jig 33, which will be described later, to pass through. More specifically, the notch 32 allows the pressing jig 33 to pass through in the thickness direction of the base end plate 14. Furthermore, the notch 32 allows the pressing jig 33 to pass through the opened part of the base end plate 14 in a direction perpendicular to the thickness direction of the base end plate 14.

[0034] The coil spring 13 is disposed in a compressed state between the valve element 12 (more specifically, the valve body 30) and the base end plate 14. Therefore, the coil spring 13 biases the valve element 12 toward the tip of the relief flow passage 20 (i.e., the discharge flow passage 19). Furthermore, the movement of the valve element 12 toward the tip side of the relief flow passage 20 is restricted by the annular portion 25. At this time, the tip surface of the valve body 30 is located closer to the tip side of the relief flow passage 20 than the discharge port 23. As a result, the oil discharged from the pump unit 11 to the discharge flow passage 19 is not discharged from the discharge port 23 through the relief flow passage 20.

[0035] On the other hand, when the pressure of the oil in the discharge flow passage 19 increases, the valve body 12 is pushed by the oil that has flowed from the discharge flow passage 19 into the relief flow passage 20, and moves toward the base end of the relief flow passage 20 against the biasing force of the coil spring 13. Then, when the pressure of the oil in the discharge flow passage 19 reaches or exceeds a threshold value, the tip face of the valve body 30 moves toward the base end of the relief flow passage 20 from the discharge port 23, opening the discharge port 23. This causes a portion of the oil in the discharge flow passage 19 to be discharged from the discharge port 23 through the relief flow passage 20. As a result, the pressure of the oil in the discharge flow passage 19 is maintained below the threshold value.

[0036] That is, the pump cover 16 (housing) in which the relief flow passage 20, the discharge port 23, the base end opening 24, the annular space 26, and the insertion opening 27 are formed, the valve body 12, the coil spring 13, and the base end plate 14 constitute a relief valve 34 that discharges a portion of the oil in the discharge flow passage 19 (in other words, maintains the pressure of the oil in the discharge flow passage 19 below a threshold value). In addition, the relief valve 34 is not limited to constituting a part of the pump section 4, and may be constituted independently of the pump section 4.

[0037] [How to assemble the relief valve 34] Next, a method of assembling the relief valve 34 will be described with reference to Figures 4 to 6. Figures 4(A), 5(A), and 6(A) are cross sections of the relief valve 34 parallel to the rotation shaft 7 and the extension direction of the relief flow passage 20. Figures 4(B), 5(B), and 6(B) are cross sections of the relief valve 34 perpendicular to the rotation shaft 7. Figures 4(C) and 5(C) are views of Figures 4(A) and 5(A) as viewed from the arrow C.

[0038] First, the valve element 12 and the coil spring 13 are inserted into the relief flow passage 20 through the base end opening 24. More specifically, the valve element 12 is inserted into the relief flow passage 20 with the tip surface of the valve body 30 facing the tip side of the relief flow passage 20. Next, the coil spring 13 is inserted into the relief flow passage 20 and fitted onto the guide rod 31.

[0039] Next, as shown in Fig. 4, a pressing jig 33 is inserted into the relief flow passage 20 through the base end opening 24. As shown in Fig. 4(C), the tip of the pressing jig 33 is roughly rectangular. The tip of the pressing jig 33 abuts against the base end of the coil spring 13. When the pressing jig 33 is pressed in this state, the tip surface of the valve body 30 abuts against the annular portion 25, restricting the movement of the valve element 12, and the coil spring 13 sandwiched between the base end surface of the valve body 30 and the tip of the pressing jig 33 is compressed. As a result, the base end of the coil spring 13 moves from the annular space 26 to the tip side of the relief flow passage 20.

[0040] 5, the base end plate 14 is inserted into the relief flow passage 20 and the annular space 26 through the insertion opening 27, with the side of the base end plate 14 opened by the cutout 32 facing the relief flow passage 20. At this time, the pressing jig 33 already inserted into the relief flow passage 20 enters the inside of the base end plate 14 through the open portion of the cutout 32. The base end plate 14 is also disposed across the relief flow passage 20 and the annular space 26.

[0041] 6, the pressing jig 33 is removed from the relief flow passage 20 through the base end opening 24. As a result, the pressing jig 33 passes through the base end plate 14 in the thickness direction and is removed from the relief flow passage 20. As the pressing jig 33 is removed, the coil spring 13 expands and its base end comes into contact with the base end plate 14. The base end plate 14 is engaged with the step between the relief flow passage 20 and the annular space 26 to support the coil spring 13. The force of the coil spring 13 attempting to expand prevents the base end plate 14 from falling off through the insertion opening 27.

[0042] [Effects of the first embodiment] According to the first embodiment, by supporting the base end of the coil spring 13 on the base end plate 14 disposed across the relief flow passage 20 and the annular space 26, it is not necessary to screw the relief plate that closes the base end opening 24 to the pump cover 16. As a result, it is possible to obtain a relief valve 34 that is lightweight and requires fewer manufacturing steps. This also contributes to reducing the weight and manufacturing steps of the pump section 4 (pump device) including the relief valve 34 and the electric pump 1 including the pump section 4, thereby contributing to carbon neutrality.

[0043] Furthermore, according to the first embodiment, by providing the cutout 32 in the base end plate 14, the relief valve 34 can be assembled in a simple procedure shown in Figures 4 to 6. This allows the number of manufacturing steps for the relief valve 34 to be further reduced.

[0044] [Second embodiment] [Configuration of pump section 4A] A pump section 4A according to the second embodiment will be described with reference to Figs. 7 to 10. Fig. 7 is an exploded perspective view of the pump section 4A according to the second embodiment, as viewed from the motor section 2 side. Fig. 8 is an exploded perspective view of the pump section 4A according to the second embodiment, as viewed from the opposite side to the motor section 2. Fig. 9 is a view showing the pump section 4A in a state in which the coil spring 13 is pressed by a pressing jig 37 according to the second embodiment. Fig. 10 is a view showing the pump section 4A in a state in which the base end plates 14A, 14B according to the second embodiment are inserted. Note that a detailed description of commonalities with the first embodiment will be omitted, and differences will be mainly described.

[0045] First, base end plates 14A, 14B according to the second embodiment differ from the first embodiment in that notches 32 are formed. Also, base end plate 14B according to the modified example of the second embodiment differs from the first embodiment in that it includes locking projections 35. Also, pump cover 16 according to the second embodiment differs from the first embodiment in that it further includes pressing opening 36. Furthermore, pressing jig 37 according to the second embodiment differs from the first embodiment in that it is a rod-shaped member that can be inserted into relief valve 34 through pressing opening 36.

[0046] As shown in Figs. 7 and 8, the base end plate 14A according to the second embodiment is a rectangular flat plate without the notch 32. Also, as shown in Fig. 10(B), the base end plate 14B according to the modified example of the second embodiment further includes a locking projection 35. The locking projection 35 protrudes in the thickness direction from the surface of the base end plate 14B. Also, the locking projection 35 has a disk shape that is slightly smaller than the diameter of the relief flow channel 20. Then, when the base end plate 14B is accommodated across the relief flow channel 20 and the annular space 26, the locking projection 35 enters the base end opening 24 side of the relief flow channel 20 from the annular space 26, and prevents the base end plate 14B from falling off through the insertion opening 27.

[0047] The pressing opening 36 is an opening for inserting the pressing tool 37 into the relief flow passage 20. The pressing opening 36 opens a part of the side surface of the relief flow passage 20 to the outside of the pump cover 16. The pressing opening 36 extends in the extension direction of the relief flow passage 20 from the base end to the tip end of the relief flow passage 20. The base end of the pressing opening 36 is connected to the base end opening 24. The tip end of the pressing opening 36 reaches the tip side of the relief flow passage 20 beyond the annular space 26 and the insertion opening 27. That is, the pressing opening 36 extends in the extension direction of the relief flow passage 20 across the insertion opening 27. The pressing opening 36 is formed, for example, on the same surface as the suction port 21, the discharge port 22, the discharge port 23, and the insertion opening 27 of the pump cover 16.

[0048] The relief valve 34A of the second embodiment is constituted by the pump cover 16 (housing) in which the relief flow path 20, the exhaust port 23, the base end opening 24, the annular space 26, the insertion opening 27, and the pressure opening 36 are formed, the valve body 12, the coil spring 13, and the base end plate 14A (or the base end plate 14B).

[0049] [How to assemble the relief valve 34A] First, the valve body 12 and the coil spring 13 are inserted into the relief flow passage 20 through the base end opening 24. Next, the pressing jig 37 is inserted into the relief flow passage 20 from the base end opening 24 side of the pressing opening 36. Then, the pressing jig 37 is moved along the pressing opening 36 toward the tip side of the relief flow passage 20. As a result, as shown in Fig. 9(A), the coil spring 13 is compressed by the valve body 12 and the pressing jig 37, whose movement is restricted by the annular portion 25, and the base end of the coil spring 13 moves from the annular space 26 to the tip side of the relief flow passage 20.

[0050] Next, as shown in Fig. 9(B), the base end plate 14A is inserted into the relief flow passage 20 and the annular space 26 through the insertion opening 27. Next, the pressing jig 37 is removed from the relief flow passage 20 through the pressing opening 36 in a direction perpendicular to the extension direction of the relief flow passage 20. This causes the coil spring 13 to expand, and the base end of the coil spring 13 comes into contact with the base end plate 14A, as shown in Fig. 10(A). Then, the base end plate 14A is engaged with the step between the relief flow passage 20 and the annular space 26 to support the coil spring 13.

[0051] In the second embodiment, instead of the base end plate 14A, the base end plate 14B can be used through the insertion opening 27. More specifically, the base end plate 14B is inserted into the relief flow passage 20 and the annular space 26 through the insertion opening 27 with the locking projection 35 facing the base end side of the relief valve 34. When the pressing jig 37 is removed through the pressing opening 36 in this state, the base end plate 14B is pressed toward the base end side of the relief flow passage 20 by the coil spring 13, and the locking projection 35 enters the base end opening 24 side from the annular space 26 of the relief flow passage 20 as shown in FIG.

[0052] [Effects of the second embodiment] The second embodiment can also provide the same effects as the first embodiment. Moreover, unlike the first embodiment, there is no restriction on the size of the notch 32 and the pressing jig 33, and therefore the manufacturing process of the relief valve 34A can be further simplified.

[0053] Furthermore, according to the second embodiment, by employing the base end plate 14B, in addition to the biasing force of the coil spring 13, the locking projection 35 can effectively prevent the base end plate 14B from falling off.

[0054] The embodiments of the present invention have been described above. Note that the present invention is not limited to the above-described embodiments, and various modified examples are included. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those having all of the configurations described. In addition, it is possible to replace a part of the configuration of this embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of this embodiment. Furthermore, it is possible to add, delete, or replace a part of the configuration of this embodiment with another configuration. [Explanation of symbols]

[0055] 1: Electric pump 2: Motor section 3: Control section 4, 4A: Pump section 5: Motor device 6: Electric motor 7: Rotation axis 8: Motor housing 10: Pump housing 11: Pump unit 12: Valve body 13: Coil spring 14, 14A, 14B: Base plate 15: Pump case 16: Pump cover 17a-17c :Bolt 18: Suction channel 19: Discharge flow path 20: Relief channel 21: Intake port 22:Discharge port 23: Outlet 24: Proximal opening 25: Circular section 26: Annular space 27: Insertion opening 28: Outer Rotor 29: Inner Rotor 30: Valve body 31: Guide rod 32: Notch 33, 37: Pressing tool 34, 34A: Relief valve 35: Locking protrusion 36: Press opening

Claims

1. a housing having a relief flow passage connected to a discharge flow passage that discharges liquid compressed by a pump and extends linearly, and a discharge port that opens a part of a side surface of the relief flow passage to the outside and discharges liquid that has flowed into the relief flow passage from the discharge flow passage to the outside; a valve body accommodated in the relief flow passage so as to be capable of reciprocating; a coil spring that is accommodated on a side of the relief flow path opposite the discharge flow path with the valve body therebetween, the coil spring having a tip that abuts against the valve body, The housing includes: a base end opening that opens an end of the relief flow passage opposite to the discharge flow passage to the outside and allows the valve body and the coil spring to enter the relief flow passage; an annular space extending radially outward from the relief flow passage and continuing in a circumferential direction between the outlet and the base end opening; An insertion opening is formed to open a circumferential portion of the annular space to the outside, a base end plate that is accommodated across the relief flow passage and the annular space through the insertion opening and abuts against a base end of the coil spring, thereby biasing the coil spring against the valve body toward the discharge flow passage.

2. 2. The relief valve according to claim 1, a base end plate having a notch formed therein through which a pressing tool can pass, the pressing tool being inserted into the relief flow passage through the base end opening and pressing the coil spring toward the discharge flow passage.

3. 2. The relief valve according to claim 1, a pressure opening formed in the housing that opens a portion of a side surface of the relief flow passage to the outside and allows a pressure tool to enter the relief flow passage and press the base end of the coil spring from the annular space toward the discharge flow passage.

4. The relief valve according to claim 3, A relief valve characterized in that the base end plate is provided with a locking protrusion that, when housed across the relief flow passage and the annular space, enters the base end opening side from the annular space of the relief flow passage to prevent the base end plate from falling off through the insertion opening.

5. A relief valve according to claim 1; a pump accommodated in the housing and configured to discharge a liquid, The housing includes: a suction flow passage for supplying liquid sucked from the outside to the pump; The pump device further comprises a discharge passage for discharging the liquid compressed by the pump to the outside.

6. A pump device according to claim 5 ; and an electric motor that drives the pump.

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