Coolant pump

Abstract

To provide a coolant pump 1 capable of improving pump efficiency.SOLUTION: The coolant pump 1 includes a rotary shaft 2, an impeller 3 fixed to the rotary shaft 2, and a pump casing 4 having a pump suction port 4i and a pump discharge port 4o of the coolant pump 1, wherein the pump casing 4 includes a suction casing 4A having the pump suction port 4i and accommodating the impeller 3 therein and a pump discharge port 4o. A discharge casing 4B disposed above the suction casing 4A, and an intermediate casing 4C located between the suction casing 4A and the discharge casing 4B and configured separately from the suction casing 4A and the discharge casing 4B, the intermediate casing 4C including an outer cylinder portion 4 CM and an inner cylinder portion 4 CL located between the outer cylinder portion 4 CM and the rotary shaft 2 in the radial direction, fluid F discharged from the impeller 3 flows into the discharge casing 4B after passing through the first circumferential flow path Q between the outer cylinder portion 4 CM and the inner cylinder portion 4 CL of the intermediate casing 4C.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a coolant pump. [Background technology]

[0002] In conventional coolant pumps, in order to ensure the necessary immersion depth (and thus the axial length of the pump casing), a section of the pump casing below the discharge casing that does not house an impeller (also called a "void section") may be provided (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Registered Utility Model No. 3041498 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the above-mentioned conventional coolant pumps have room for improvement in pump efficiency.

[0005] SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has an object to provide a coolant pump that can improve pump efficiency. [Means for solving the problem]

[0006] [1] A coolant pump, A rotation axis; an impeller fixed to the rotating shaft; a pump casing having a pump suction port and a pump discharge port of the coolant pump; Equipped with The pump casing comprises: a suction casing having the pump suction port and accommodating the impeller therein; a discharge casing having the pump discharge port and disposed above the suction casing; an intermediate casing located between the suction casing and the discharge casing and configured separately from the suction casing and the discharge casing; Equipped with The intermediate casing includes: an outer cylinder portion; an inner cylindrical portion located between the outer cylindrical portion and the rotation shaft in a radial direction; and A coolant pump configured so that the fluid discharged from the impeller passes through a first circular flow path between the outer cylindrical portion and the inner cylindrical portion of the intermediate casing, and then flows into the discharge casing.

[0007] [2] The intermediate casing is one or more guide members extending spirally within the first circular flow path; The coolant pump according to [1], further comprising:

[0008] [3] The coolant pump according to [2], wherein each of the guide members is connected to at least one of the outer cylindrical portion and the inner cylindrical portion.

[0009] [4] A coolant pump described in any one of [1] to [3], wherein the outer tube portion of the intermediate casing is made up of multiple outer tube segment members that are constructed separately from each other and arranged along the axial direction.

[0010] [5] A coolant pump described in any one of [1] to [4], wherein the inner cylindrical portion of the intermediate casing is made up of a plurality of inner cylindrical segment members that are constructed separately from each other and arranged along the axial direction.

[0011] [6] A coolant pump according to [5], wherein the outer circumferential surface of at least one of the inner cylinder segments extends parallel to the axial direction over the entire axial length.

[0012] [7] The intermediate casing has a plurality of divided casing members that are formed separately from each other and arranged along the axial direction, Each of the divided casing members includes: an outer cylinder segment that constitutes a part of the outer cylinder portion; an inner cylinder segment that constitutes a part of the inner cylinder portion; one or more guide members that connect the outer cylinder segment and the inner cylinder segment; The coolant pump according to [2],

[0013] [8] The discharge casing is a discharge outer peripheral wall portion; an annular discharge inner peripheral wall portion disposed around the rotation shaft on the inner peripheral side of the discharge outer peripheral wall portion; and A coolant pump according to any one of [1] to [7], wherein, in the axial direction, the upper end of the inner cylindrical portion of the intermediate casing is closely opposed to the lower end of the discharge inner wall portion of the discharge casing.

[0014] [9] The coolant pump according to any one of [1] to [8], wherein at least a portion of the inner circumferential surface of the outer cylindrical portion of the intermediate casing extends parallel to the axial direction. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a coolant pump that can improve pump efficiency. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is an axial cross-sectional view schematically showing a coolant pump according to a first embodiment of the present invention. [Figure 2] 2(a) is a perspective view schematically showing the split casing member of FIG. 1 as viewed obliquely from above, and FIG. 2(b) is a perspective view schematically showing the bottom wall of FIG. 1 as viewed obliquely from above. [Figure 3]FIG. 5 is an axial cross-sectional view schematically showing a coolant pump according to a second embodiment of the present invention. [Figure 4] Figure 4(a) is a perspective view that schematically shows the intermediate casing of Figure 3 as viewed from diagonally above, and Figure 4(b) is a perspective view that schematically shows the intermediate casing of Figure 4(a) as viewed from diagonally below. [Figure 5] FIG. 6 is an axial cross-sectional view schematically showing a coolant pump according to a third embodiment of the present invention. [Figure 6] FIG. 10 is an axial cross-sectional view schematically showing a coolant pump according to a fourth embodiment of the present invention. [Figure 7] 7(a) is a perspective view showing the inner tube portion of FIG. 6 as viewed obliquely from above, and FIG. 7(b) is a perspective view showing the outer tube portion and guide member of FIG. 6 as viewed obliquely from above. [Figure 8] FIG. 10 is an axial cross-sectional view schematically showing a coolant pump according to a fifth embodiment of the present invention. [Figure 9] Figure 9(a) is a perspective view schematically showing the inner tube portion and guide member of Figure 8 as viewed from diagonally above, and Figure 9(b) is a perspective view schematically showing the outer tube portion of Figure 8 as viewed from diagonally above. [Figure 10] FIG. 10 is an axial cross-sectional view schematically showing a coolant pump according to a sixth embodiment of the present invention. [Figure 11] FIG. 10 is an axial cross-sectional view schematically showing a coolant pump according to a seventh embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] The coolant pump according to the present invention can be suitably used as an immersion type coolant pump.

[0018] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a coolant pump according to the present invention will be described with reference to the drawings. In each drawing, the same members and parts are designated by the same reference numerals.

[0019] 1 to 11 schematically show coolant pumps 1 according to various embodiments of the present invention. For convenience of explanation, these embodiments will be described in parallel below. Figures 1 and 2 show a coolant pump 1 according to a first embodiment of the present invention, Figures 3 and 4 show a coolant pump 1 according to a second embodiment of the present invention, Figure 5 shows a coolant pump 1 according to a third embodiment of the present invention, Figures 6 and 7 show a coolant pump 1 according to a fourth embodiment of the present invention, Figures 8 and 9 show a coolant pump 1 according to a fifth embodiment of the present invention, Figure 10 shows a coolant pump 1 according to a sixth embodiment of the present invention, and Figure 11 shows a coolant pump 1 according to a seventh embodiment of the present invention.

[0020] 1, 3, 5-6, 8, 10-11, the coolant pump 1 of each embodiment of the present invention is configured to be fixed to a tank T that stores a fluid F (specifically, a liquid such as a coolant liquid) during use, and in this state to pressurize the fluid F in the tank T and discharge it to the outside. The fluid F discharged from the coolant pump 1 is supplied to a processing device or the like via piping (not shown), and then returns to the tank T again via piping (not shown).

[0021] The coolant pump 1 of each embodiment of the present invention includes a rotating shaft 2 , one or more impellers 3 , and a pump casing 4 .

[0022] The rotary shaft 2 is driven to rotate (spin) around the central axis of the rotary shaft 2 by a main body of a motor (not shown). The main body of the motor is located above the pump casing 4. The rotating shaft 2 may consist of only the output shaft of the motor, or may consist of the output shaft of the motor and a pump shaft (not shown) connected to the lower end of the output shaft of the motor by a coupling or the like. As in the illustrated embodiments (FIGS. 1, 3, 5 to 6, 8, 10 to 11), a nut N and a washer W may be provided at the lower end of the rotating shaft 2.

[0023] Hereinafter, the central axis O of the coolant pump 1 will be referred to as the central axis of the rotation shaft 2 (and thus as the rotation shaft 2). The direction parallel to the central axis O of the coolant pump 1 will be referred to as the "axial direction." When the coolant pump 1 is in use, the axial direction is oriented vertically, with one side in the axial direction being the lower side in the vertical direction and the other side in the axial direction being the upper side in the vertical direction. In this specification, one side in the axial direction will be referred to as the "lower side," and the other side in the axial direction will be referred to as the "upper side." In this specification, the direction perpendicular to the axial direction will be referred to as the "axial-perpendicular direction." When the coolant pump 1 is in use, the axial-perpendicular direction will be the horizontal direction. Furthermore, in this specification, unless otherwise specified, the terms "circumferential direction" and "radial direction" refer to the circumferential direction and radial direction, respectively, centered on the central axis O of the coolant pump 1, the "inner peripheral side" refers to the side closer to the central axis O of the coolant pump 1, and the "outer peripheral side" refers to the side farther from the central axis O of the coolant pump 1.

[0024] One or more impellers 3 are fixed to the rotary shaft 2 and configured to rotate around the central axis O of the coolant pump 1 as the rotary shaft 2 rotates. In each of the illustrated embodiments, only one impeller 3 is provided. The impeller 3 is supported from below by a washer W. When a plurality of impellers 3 are provided, the plurality of impellers 3 are arranged along the axial direction.

[0025] In each embodiment shown in the figures, the inlet of the impeller 3 (impeller inlet 3i) faces downward, and the outlet of the impeller 3 (impeller outlet 3o) faces the outer periphery and is located more outer periphery than the inlet of the impeller 3. As a result, the impeller 3 is configured so that the fluid F enters the impeller 3 in an upward direction from the impeller inlet 3i, and then exits from the impeller outlet 3o while moving toward the outer periphery. In each of the illustrated embodiments, the impeller 3 has an extension 3s that extends on the outer circumferential surface of the rotary shaft 2 and extends above the impeller outlet 3o. However, the extension 3s is not essential.

[0026] The pump casing 4 has a suction port (pump suction port 4i) and a discharge port (pump discharge port 4o) of the coolant pump 1, and defines a flow path from the pump suction port 4i to the pump discharge port 4o. In each illustrated embodiment, the central axis of the pump suction port 4i extends in the axial direction and coincides with the central axis O of the coolant pump 1. In each illustrated embodiment, the central axis of the pump discharge port 4o extends in the radial direction (and therefore in the direction perpendicular to the axis). However, the central axis of the pump suction port 4i and the central axis of the pump discharge port 4o may each extend in any direction.

[0027] The pump casing 4 includes a suction casing 4A, a discharge casing 4B, and an intermediate casing 4C. No other casing is provided between the suction casing 4A and the discharge casing 4B other than the intermediate casing 4C. The suction casing 4A has a pump suction port 4i and houses one or more impellers 3 therein. The discharge casing 4B has a pump discharge port 4o and is disposed above the suction casing 4A. The intermediate casing 4C is located between the suction casing 4A and the discharge casing 4B in the axial direction, and is configured as a separate body from the suction casing 4A and the discharge casing 4B. The suction casing 4A, the intermediate casing 4C, and the discharge casing 4B may be connected to one another by any method such as fastening. The illustrated embodiments (Figures 1, 3, 5-6, 8, 10-11) essentially differ from each other only in the configuration of the intermediate casing 4C, and the configurations of the other parts (suction casing 4A, discharge casing 4B, etc.) are substantially the same.

[0028] In each of the illustrated embodiments, the suction casing 4A is made up of one part. However, the suction casing 4A may be made up of multiple parts that are configured separately from each other, and these multiple parts may be arranged, for example, along the axial direction. In each of the illustrated embodiments, the suction casing 4A accommodates only one impeller 3 therein. However, the suction casing 4A may accommodate a plurality of impellers 3 therein. In each of the illustrated embodiments, the pump suction port 4i is defined by the lower end of the suction casing 4A. The outer peripheral portion of the suction casing 4A constitutes a suction outer peripheral wall portion 4Aw. The upper end of the suction casing 4A and the lower end of an outer cylindrical portion 4CM (described later) of the intermediate casing 4C are in contact with each other. More specifically, in each of the illustrated embodiments, the outer cylindrical portion 4CM of the intermediate casing 4C is placed on the outer circumferential wall portion 4Aw of the suction casing 4A. However, the configuration of the suction casing 4A is not limited to those in the illustrated embodiments, and may be any configuration.

[0029] In each of the illustrated embodiments, the discharge casing 4B has a discharge outer wall portion 4Bw, which is the outermost wall portion of the discharge casing 4B, an annular discharge inner wall portion 4Bx arranged around the rotating shaft 2 on the inner side of the discharge outer wall portion 4Bw, a tubular discharge pipe portion 4Bd, a first partition wall 4Ba, and a second partition wall 4Bb.

[0030] The lower end of the discharge outer peripheral wall 4Bw of the discharge casing 4B is in contact with the upper end of an outer cylindrical portion 4CM (described later) of the intermediate casing 4C. More specifically, in each of the illustrated embodiments, the discharge outer peripheral wall 4Bw of the discharge casing 4B is placed on the outer cylindrical portion 4CM (described later) of the intermediate casing 4C.

[0031] In each of the illustrated embodiments, the discharge pipe portion 4Bd of the discharge casing 4B is disposed at a position spaced apart from the rotary shaft 2 in the direction perpendicular to the axis. Here, with regard to the discharge pipe section 4Bd, "disposed at a position spaced apart from the rotary shaft 2 in the axial direction" means that the wall section on the inner periphery side of the discharge pipe section 4Bd (the side closer to the central axis O of the coolant pump 1) is spaced apart from the rotary shaft 2 in the axial direction. Accordingly, the discharge flow path DP defined by the discharge pipe section 4Bd is spaced apart from the rotary shaft 2 of the coolant pump 1 in the axial direction. The discharge pipe 4Bd defines a discharge flow path DP that extends upward, then bends radially outward to the outer periphery (diametrically outward) and reaches the pump discharge port 4o. The end of the discharge pipe 4Bd that defines the pump discharge port 4o is located outside the tank T, on the upper wall surface of the tank T. The wall of the discharge pipe 4Bd on the outer periphery (the side farther from the central axis O of the coolant pump 1) forms part of the discharge outer periphery wall 4Bw of the discharge casing 4B. The wall of the discharge pipe 4Bd on the inner periphery (the side closer to the central axis O of the coolant pump 1) is continuous upward from the discharge inner periphery wall 4Bx of the discharge casing 4B.

[0032] In each illustrated embodiment, the discharge casing 4B defines a second circulating flow path J extending circumferentially between the discharge outer peripheral wall portion 4Bw and the discharge inner peripheral wall portion 4Bx below the discharge pipe portion 4Bd (and thus the discharge flow path DP). The second circumferential flow path J is open at its lower side, thereby communicating with a first circumferential flow path Q (described below) of the intermediate casing 4C located below it. The discharge flow path DP continues from a circumferential portion of the second circumferential flow path J to its upper side. In each illustrated embodiment, a portion of the discharge inner peripheral wall portion 4Bx is located below the lower end of the discharge outer peripheral wall portion 4Bw and faces the outer cylindrical portion 4CM of the intermediate casing 4C in a direction perpendicular to the axis, with a space between them. As a result, a portion of the second circumferential flow path J is also defined by the outer cylindrical portion 4CM of the intermediate casing 4C. Therefore, specifically, the second circulating flow path J extends circumferentially between the inner surface of the discharge outer wall portion 4Bw of the discharge casing 4B, the inner surface of the outer tube portion 4CM of the intermediate casing 4C, the outer surface of the discharge inner wall portion 4Bx, and the lower surface of the first partition wall 4Ba described below.

[0033] In each of the illustrated embodiments, the discharge inner circumferential wall portion 4Bx of the discharge casing 4B is generally conical. Specifically, the portion of the outer circumferential surface of the discharge inner circumferential wall portion 4Bx that defines the second circumferential flow path J extends gradually inward along the conical shape as it moves upward. This promotes a flow (see solid arrows in FIGS. 1, 3, 5-6, 8, 10-11) of the fluid F that has flowed through the first circumferential flow path Q (described below) of the intermediate casing 4C through the second circumferential flow path J between the discharge inner circumferential wall portion 4Bx and the discharge outer circumferential wall portion 4Bw to the discharge flow path DP. As a result, the fluid F is prevented from flowing through the first circular flow path Q of the intermediate casing 4C, flowing inward along the underside of the discharge inner circumferential wall portion 4Bx, and then flowing through the gap (shaft seal gap) of the shaft seal portion E (see the dashed arrows in FIGS. 1, 3, 5-6, 8, 10-11). In this way, the flow of the fluid F toward the shaft seal portion E can be prevented, thereby reducing resistance and improving the efficiency and discharge rate of the coolant pump 1. The lower surface of the discharge inner circumferential wall portion 4Bx extends in the direction perpendicular to the axis. However, the shape of the discharge inner circumferential wall portion 4Bx is not limited to the illustrated embodiments, and may be any shape.

[0034] In each illustrated embodiment, the discharge casing 4B has a first partition wall 4Ba extending circumferentially between the discharge inner peripheral wall portion 4Bx and the discharge outer peripheral wall portion 4Bw from one circumferential end of the discharge pipe portion 4Bd to the other circumferential end of the discharge pipe portion 4Bd. The discharge casing 4B also defines a space C around the rotating shaft 2 above the first partition wall 4Ba and at a position that overlaps with the discharge pipe portion 4Bd in the axial direction. The space C is located outside the flow path between the pump suction port 4i and the pump discharge port 4o within the pump casing 4. The first partition wall 4Ba defines a second circular flow path J with its lower surface, and defines the space C within the discharge casing 4B with its upper surface. In each of the illustrated embodiments, the first partition wall 4Ba gradually extends upward as it extends circumferentially from one circumferential end of the discharge pipe section 4Bd to the other circumferential end of the discharge pipe section 4Bd.

[0035] In each of the illustrated embodiments, a space C in the discharge casing 4B is defined above the first partition wall 4Ba by a portion of the outer discharge wall 4Bw of the discharge casing 4B other than the portion constituting the discharge pipe 4Bd, an inner wall portion of the discharge pipe 4Bd, the first partition wall 4Ba, and a second partition wall 4Bb located above the first partition wall 4Ba. The rotating shaft 2 is located within this space C.

[0036] The second partition wall 4Bb is formed in an annular shape, and the rotary shaft 2 is inserted through its central hole. The second partition wall 4Bb extends radially outward beyond the discharge outer peripheral wall portion 4Bw of the discharge casing 4B, and during use, the extending portion is disposed on the upper wall surface of the tank T outside the tank T.

[0037] The discharge outer peripheral wall portion 4Bw of the discharge casing 4B has a window R penetrating in the direction perpendicular to the axis in a portion that defines the space C. During use, the liquid level of the fluid F in the tank T is positioned below the lower end of the window R. However, the configuration of the discharge casing 4B is not limited to those in the illustrated embodiments, and may be any configuration.

[0038] In each illustrated embodiment, a tubular discharge bushing H is provided between the discharge inner circumferential wall portion 4Bx and the rotating shaft 2. The tubular discharge bushing H is fixed to the discharge inner circumferential wall portion 4Bx and extends in the axial direction. The tubular shaft sleeve S is provided on the inner circumferential side of the discharge bushing H. The discharge bushing H is a fixed portion that is not rotated by the rotation of the rotating shaft 2, while the shaft sleeve S is a rotating portion that is rotated by the rotation of the rotating shaft 2. A non-contact shaft seal E is formed between the discharge inner circumferential wall portion 4Bx and the rotating shaft 2 to prevent the fluid F in the flow path of the discharge casing 4B from leaking into the space C. More specifically, in each illustrated embodiment, the discharge bushing H and the shaft sleeve S constitute the shaft seal E. The shaft seal E has a small gap (shaft seal gap G) between the discharge bushing H and the shaft sleeve S. The shaft seal gap G is a very small gap, for example, having a width of 1 mm or less. Space C continues upward from this shaft seal gap G. The shaft seal E is configured to allow a small amount of fluid F in the flow path of the discharge casing 4B to leak into space C through this shaft seal gap G. Fluid F that leaks into space C can return to the tank T through the window R. In the coolant pump 1, the fluid F in the tank T generally contains foreign matter such as cuttings. If the shaft seal E were configured as a contact type such as a mechanical seal, foreign matter could get into the shaft seal E, causing it to lose its sealing function and requiring the shaft seal E to be replaced more frequently. Also, if the coolant pump 1 sucks in air, air could accumulate near the outlet of the impeller 3 or in the shaft seal E, reducing discharge performance and sealing function. Therefore, these problems can be avoided by configuring the shaft seal E as a non-contact type with a seal gap G, as in the illustrated embodiments. In each of the illustrated embodiments, the upper side of the discharge bushing H has an annular protrusion 4Bp that protrudes inward, on the discharge inner peripheral wall 4Bx, and this annular protrusion 4Bp closely faces the shaft sleeve S. The gap between the annular protrusion 4Bp and the shaft sleeve S is wider than the shaft seal gap G of the shaft seal E, and does not have a shaft sealing function. However, the shaft seal E may be configured as a contact type.

[0039] In each of the illustrated embodiments, one or more shaft spacers Y are provided around the rotary shaft 2 between the extension 3s of the impeller 3 and the shaft sleeve S in the axial direction.

[0040] In each of the illustrated embodiments, the intermediate casing 4C has an outer cylindrical portion 4CM and an inner cylindrical portion 4CL. The outer cylindrical portion 4CM is formed in a cylindrical shape and is the outermost wall portion of the intermediate casing 4C. The inner cylinder portion 4CL is configured in a cylindrical shape and is located radially between the outer cylinder portion 4CM and the rotating shaft 2. The inner cylinder portion 4CL is located at a distance closer to the inner periphery than the outer cylinder portion 4CM, and is also located at a distance closer to the outer periphery than the rotating shaft 2. In this way, the intermediate casing 4C has a double structure consisting of the outer cylindrical portion 4CM and the inner cylindrical portion 4CL. The intermediate casing 4C does not house the impeller 3. Therefore, the intermediate casing 4C corresponds to a so-called "empty step." By providing the intermediate casing 4C forming the empty step, the axial length of the pump casing 4 can be increased accordingly. This is advantageous from the viewpoint of ensuring the necessary immersion depth, for example, when the distance from the top surface of the tank T to the liquid surface of the fluid F in the tank T is long. A first circular flow path Q is defined between the outer cylindrical portion 4CM and the inner cylindrical portion 4CL, extending in the circumferential direction.

[0041] In each of the illustrated embodiments, the coolant pump 1 is configured so that the fluid F coming out of the impeller 3 in the suction casing 4A flows through the first circular flow path Q between the outer cylindrical portion 4CM and the inner cylindrical portion 4CL in the intermediate casing 4C, and then flows into the discharge casing 4B. More specifically, when the impeller 3 is rotated by the rotation of the rotary shaft 2, as shown by the solid arrows in Figures 1, 3, 5-6, 8, 10-11, the fluid F in the tank T is sucked into the flow passages of the coolant pump 1 from the pump suction port 4i, and this fluid F flows into the impeller inlet 3i of the impeller 3 and is pressurized by the action of centrifugal force while moving toward the outer periphery inside the impeller 3. After that, the fluid F exits the impeller outlet 3o of the impeller 3 toward the outer periphery, flows into the first circular flow passage Q of the intermediate casing 4C above it, and flows upward within the first circular flow passage Q. After flowing within the first circular flow passage Q, the fluid F then flows into the discharge casing 4B. Most of the fluid F that flows through the first circular flow path Q passes through the second circular flow path J located above it, passes through the discharge flow path DP, and is discharged from the pump discharge port 4o to the outside (see the solid arrows in FIGS. 1, 3, 5-6, 8, 10-11). A portion of the fluid F that flows through the first circular flow path Q flows inward along the lower surface of the discharge inner circumferential wall portion 4Bx, then flows upward through the seal gap G of the seal portion E, and leaks out into the space C (see the dashed arrows in FIGS. 1, 3, 5-6, 8, 10-11). When the liquid level of the fluid F in the space C reaches the lower end of the window R, the fluid F flows out of the window R to the outside of the coolant pump 1 and returns to the tank T. Furthermore, when the shaft seal portion E is configured as a contact type (mechanical seal, etc.) as described above, a portion of the fluid F that flows within the first circulating flow path Q may flow toward the inner side along the lower surface of the discharge inner wall portion 4Bx, but will not leak out through the shaft seal portion E.

[0042] As described above, in each of the illustrated embodiments, the intermediate casing 4C located between the suction casing 4A (and thus the impeller 3) and the discharge casing 4B has a double structure made up of an outer cylindrical portion 4CM and an inner cylindrical portion 4CL, and the coolant pump 1 is configured so that the fluid F coming out of the impeller 3 flows through the first circulating flow path Q between the outer cylindrical portion 4CM and the inner cylindrical portion 4CL in the intermediate casing 4C before flowing into the discharge casing 4B. The intermediate casing 4C is an empty stage that does not have an impeller 3 inside. As a configuration in which a hollow stage portion is provided, for example, the intermediate casing 4C does not have the inner cylindrical portion 4CL, and guide vanes configured to return the fluid F that flows out from the impeller 3 toward the outer periphery toward the inner periphery are provided above the impeller 3, and the guide vanes and the discharge casing 4B are separated in the axial direction. However, in this case, after the fluid F that flows out from the impeller 3 toward the outer periphery returns to the inner periphery while being guided by the guide vanes, the flow path suddenly expands before reaching the discharge casing 4B, causing the fluid F to flow in various directions, which may reduce the pump efficiency. Another possible configuration for providing a hollow stage is one in which the intermediate casing 4C does not have any components, such as the inner cylindrical portion 4CL or guide vanes, on the inner peripheral side of the outer cylindrical portion 4CM. However, in this case, the flow path of the fluid F flowing out from the impeller 3 toward the outer peripheral side expands suddenly before reaching the discharge casing 4B, causing the fluid F to flow in various directions, which may reduce the pump efficiency. In this regard, in each of the illustrated embodiments, the fluid F coming out of the impeller 3 passes through the first circulating flow path Q between the outer cylindrical portion 4CM and the inner cylindrical portion 4CL in the intermediate casing 4C, which forms the empty stage portion, and then flows into the discharge casing 4B. Therefore, even though an empty stage portion is provided, it is possible to prevent the fluid F coming out of the impeller 3 from returning to the inner periphery or the flow path from suddenly expanding until it reaches the discharge casing 4B, thereby improving pump efficiency. Furthermore, in each of the illustrated embodiments, the intermediate casing 4C is configured separately from the suction casing 4A and the discharge casing 4B, so the presence or absence and type (number of empty stages, etc.) of the intermediate casing 4C can be selected depending on the required immersion depth (and thus the axial length of the pump casing 4), etc.

[0043] In any example described in this specification, the intermediate casing 4C may be integrally constructed (i.e., made up of one part), as in the embodiment of Figures 3 to 4, or may be made up of multiple parts that are separate from each other, as in the embodiments of Figures 1 to 2 and Figures 5 to 11.

[0044] The intermediate casing 4C may further include one or more guide members 4CG in the first circular flow path Q, as in the illustrated embodiments. It is preferable that each guide member 4CG extends spirally inside the first circular flow path Q. That is, it is preferable that each guide member 4CG extends upward while heading toward one circumferential side (the same side for each guide member 4CG) (see FIGS. 2, 4, and 9). By providing the guide member 4CG, the flow direction of the fluid F in the first circular flow path Q is made more uniform, so that an efficient flow path can be formed, and the pump efficiency can be further improved. When a plurality of guide members 4CG are provided, the plurality of guide members 4CG may be offset from one another in the circumferential direction, as in the embodiments of Figures 1 to 11. And / or when a plurality of guide members 4CG are provided, the plurality of guide members 4CG may be offset from one another in the axial direction, as in the embodiment of Figure 1, or may not be offset from one another in the axial direction, as in the embodiments of Figures 3 to 4 and 6 to 9. However, the guide member 4CG does not necessarily have to be provided.

[0045] As in the illustrated embodiments, it is preferable that each guide member 4CG is connected to at least one of the outer cylindrical portion 4CM and the inner cylindrical portion 4CL (i.e., configured integrally with or fixed to), which can prevent a gap from being formed between the guide member 4CG and at least one of the outer cylindrical portion 4CM and the inner cylindrical portion 4CL, thereby making it possible to more uniformly distribute the flow direction of the fluid F within the first circular flow path Q and further improving the pump efficiency. In each of the illustrated embodiments, each guide member 4CG is integrally formed with at least one of the outer cylindrical portion 4CM and the inner cylindrical portion 4CL, thereby reducing the number of parts and improving the ease of assembly. 1 to 4, each guide member 4CG is connected to both the outer cylinder portion 4CM and the inner cylinder portion 4CL (more specifically, they are integrally formed). In this case, at least a portion of the outer cylinder portion 4CM, at least a portion of the inner cylinder portion 4CL, and one or more guide members 4CG are integrally formed. 5 to 7, each guide member 4CG is connected only to the outer cylinder portion 4CM (more specifically, configured as one unit). In this case, at least a portion of the outer cylinder portion 4CM and one or more guide members 4CG are configured as one unit, and the inner cylinder portion 4CL is configured as a separate member from the outer cylinder portion 4CM and each guide member 4CG. 8 to 11, each guide member 4CG is connected only to the inner cylinder portion 4CL (more specifically, configured as one unit). In this case, at least a portion of the inner cylinder portion 4CL and one or more guide members 4CG are configured as one unit, and the outer cylinder portion 4CM is configured as a separate member from the inner cylinder portion 4CL and each guide member 4CG. When the inner tube portion 4CL and the outer tube portion 4CM are constructed separately from each other as in the embodiments of Figures 5 to 11, if either the inner tube portion 4CL or the outer tube portion 4CM is damaged, it is possible to replace only either the inner tube portion 4CL or the outer tube portion 4CM, which provides better maintainability than when the inner tube portion 4CL and the outer tube portion 4CM are constructed as a single unit as in the embodiments of Figures 1 to 4.

[0046] In any example described in this specification, the intermediate casing 4C may form a single empty stage portion, or may form multiple empty stage portions. Here, in this specification, when referring to the number of stages, a height (length in the axial direction) equivalent to approximately one stage of the impeller 3 is counted as one stage. In each of the embodiments shown in FIGS. 1 to 10, the intermediate casing 4C has two empty stages, and in the embodiment shown in FIG. 11, the intermediate casing 4C has three empty stages.

[0047] In any example described herein, the outer cylinder portion 4CM of the intermediate casing 4C may be integrally formed (i.e., made of a single part) as in the embodiments of Figures 3 to 4 and 6 to 11. In this case, the outer cylinder portion 4CM may be configured for a single stage (i.e., having an axial length corresponding to one stage), or may be configured for multiple stages (i.e., having an axial length corresponding to multiple stages). In the embodiments of Figures 3 to 4 and 6 to 10, the outer cylinder portion 4CM is configured for two stages, and in the embodiment of Figure 11, the outer cylinder portion 4CM is configured for three stages. Alternatively, in any example described herein, the outer cylinder portion 4CM of the intermediate casing 4C may be composed of multiple outer cylinder segments 4CMP that are formed separately from each other and arranged along the axial direction, as in the embodiments of FIGS. 1 to 2 and 5. Each outer cylinder segment 4CMP is cylindrical and integrally formed (i.e., composed of a single part). The multiple outer cylinder segments 4CMP are stacked in the axial direction. Note that in the embodiments of FIGS. 1 to 2 and 5, the outer cylinder portion 4CM is composed of two outer cylinder segments 4CMP. Each outer cylinder segment 4CMP may be configured for a single stage (i.e., have an axial length equivalent to one stage) or may be configured for multiple stages (i.e., have an axial length equivalent to multiple stages). Note that in the embodiments of FIGS. 1 to 2 and 5, each outer cylinder segment 4CMP is configured for a single stage.

[0048] In any example described herein, the inner cylindrical portion 4CL of the intermediate casing 4C may be configured as a single unit (i.e., made of a single part) as in the embodiments of Figures 3 to 4 and 6 to 9. In this case, the inner cylindrical portion 4CL may be configured for a single stage (i.e., having an axial length equivalent to one stage), or may be configured for multiple stages (i.e., having an axial length equivalent to multiple stages). Note that in the embodiments of Figures 3 to 4 and 6 to 9, the inner cylindrical portion 4CL is configured for two stages. Alternatively, in any example described herein, the inner cylinder portion 4CL of the intermediate casing 4C may be composed of multiple inner cylinder segment members 4CLP that are configured separately from each other and arranged along the axial direction, as in the embodiments of FIGS. 1 to 2, 5, and 10 to 11. Each inner cylinder segment member 4CLP is cylindrical and configured as a single unit (i.e., made up of a single part). The multiple inner cylinder segment members 4CLP may be spaced apart from each other in the axial direction, as in the embodiment of FIGS. 1 to 2, or may be stacked in the axial direction (and ultimately contact each other) as in the embodiments of FIGS. 5, 10 to 11. Note that in each of the embodiments of FIGS. 1 to 2, 5, and 10 to 11, the inner cylinder portion 4CL is composed of two inner cylinder segment members 4CLP. Each inner cylinder segment 4CLP may be configured for a single stage (i.e., have an axial length equivalent to one stage), or may be configured for multiple stages (i.e., have an axial length equivalent to multiple stages). In the embodiments of FIGS. 1 to 2, 5, and 10, each inner cylinder segment 4CLP is configured for a single stage. In the embodiment of FIG. 11, the inner cylinder portion 4CL is made up of a two-stage inner cylinder segment 4CLP and a single-stage inner cylinder segment 4CLP placed on top of it.

[0049] In any example described herein, the intermediate casing 4C may have a plurality of divided casing members 4CK that are formed separately from one another and arranged along the axial direction, as in the embodiment of Figures 1 and 2. Each divided casing member 4CK is formed as a single unit (i.e., made of a single part). Each divided casing member 4CK has an outer cylinder segment 4CMP that forms part of the axial direction of the outer cylinder portion 4CM, an inner cylinder segment 4CLP that forms part of the axial direction of the inner cylinder portion 4CL, and one or more guide members 4CG that connect the outer cylinder segment 4CMP and the inner cylinder segment 4CLP to each other. The outer cylinder segment 4CMP and the inner cylinder segment 4CLP are each cylindrical. In the embodiment shown in FIGS. 1 and 2, the intermediate casing 4C is made up of two separate casing members 4CK. Each divided casing member 4CK may be configured for a single stage (i.e., have an axial length equivalent to one stage), or may be configured for multiple stages (i.e., have an axial length equivalent to multiple stages). In the embodiment shown in Figures 1 and 2, each divided casing member 4CK is configured for a single stage. In this way, when the intermediate casing 4C has a plurality of split casing members 4CK, the axial length of the intermediate casing 4C can be easily adjusted simply by adjusting the number of split casing members 4CK to be stacked. Also, when each split casing member 4CK is configured for a single stage (FIGS. 1 and 2), the number of empty stages made up of the intermediate casing 4C can be easily adjusted simply by adjusting the number of split casing members 4CK to be stacked.

[0050] In addition, as in the embodiment of Figures 3 and 4, when the intermediate casing 4C forms multiple empty stages, and the entire intermediate casing 4C is constructed as a single unit and consists of a single part (and thus the outer tube portion 4CM, the inner tube portion 4CL and one or more guide members 4CG are constructed as a single unit), costs can be reduced compared to when the intermediate casing 4C has multiple split casing members 4CK as in the embodiment of Figures 1 and 2, and gaps that may form between the inner tube split members 4CLP of the split casing members 4CK when multiple split casing members 4CK are stacked as in the embodiment of Figures 1 and 2 can be avoided, thereby improving pump efficiency and also increasing the design freedom of the guide members 4CG.

[0051] In any example described in this specification, the inner surface of the outer tube portion 4CM of the intermediate casing 4C may have any shape, and may, for example, extend parallel to the axial direction over at least a portion of the outer tube portion 4CM in the axial direction (approximately the entire length in each of the embodiments of Figures 1 to 11), as in each of the embodiments of Figures 1 to 11.

[0052] In any example described herein, the outer peripheral surface of the inner cylindrical portion 4CL of the intermediate casing 4C may have any shape, and may extend parallel to the axial direction over substantially the entire length of the inner cylindrical portion 4CL in the axial direction, as in the embodiments of Figures 1 to 2 and 5, or may extend non-parallel to the axial direction over at least a portion of the inner cylindrical portion 4CL in the axial direction, as in the embodiments of Figures 3 to 4 and 6 to 11. In the latter case, the portion of the outer peripheral surface of the inner cylindrical portion 4CL of the intermediate casing 4C that extends non-parallel to the axial direction may extend linearly in a direction inclined with respect to the axial direction when viewed in axial cross section, as in the embodiments of Figures 3 to 4, or may have a curved linear shape (for example, convex toward the outer periphery) as in the embodiments of Figures 6 to 11.

[0053] When the inner cylinder portion 4CL of the intermediate casing 4C is made up of multiple inner cylinder segment members 4CLP, at least one of the inner cylinder segment members 4CLP may be a straight cylinder member 4CLPk, as in the embodiments of Figures 10 to 11. The straight cylinder member 4CLPk has an outer circumferential surface that extends parallel to the axial direction over its entire axial length, and therefore has a constant outer diameter. In this specification, for convenience of explanation, inner cylinder segment members 4CLP that do not correspond to linear cylinder members 4CLPk may be referred to as "non-linear cylinder members 4CLPw." In each of the embodiments in Figures 10 to 11, the linear cylinder member 4CLPk is placed on the non-linear cylinder member 4CLPw. The straight cylindrical member 4CLPk may be configured for a single stage (i.e., have an axial length equivalent to one stage), or may be configured for multiple stages (i.e., have an axial length equivalent to multiple stages). According to the straight cylindrical member 4CLPk, for example, when it is desired to increase the axial length of the inner cylindrical portion 4CL, the axial length of the inner cylindrical portion 4CL can be easily increased by simply adding one or more straight cylindrical members 4CLPk, thereby reducing the need to prepare separate inner cylindrical portions 4CL or inner cylindrical segmented members 4CLP (e.g., non-straight cylindrical members 4CLPw) for each different number of stages (and therefore for each different axial length). Furthermore, the straight cylindrical member 4CLPk is easier to manufacture and has superior pump efficiency than the non-straight cylindrical member 4CLPw.

[0054] In any example described in this specification, as in each illustrated embodiment, the upper end 4CLe of the inner cylindrical portion 4CL of the intermediate casing 4C may be closely opposed to (including in contact with) the lower end 4Be of the discharge inner circumferential wall portion 4Bx of the discharge casing 4B in the axial direction. In this case, the gap between the inner cylindrical portion 4CL of the intermediate casing 4C and the discharge inner circumferential wall portion 4Bx of the discharge casing 4B in the axial direction can be reduced, and therefore the fluid F from the first circulating flow path Q can more smoothly enter the second circulating flow path J, improving pump efficiency. Specifically, the axial distance between the upper end 4CLe of the inner cylindrical portion 4CL of the intermediate casing 4C and the lower end 4Be of the discharge inner circumferential wall portion 4Bx of the discharge casing 4B is preferably 10 mm or less. Furthermore, the upper end 4CLe of the inner cylindrical portion 4CL of the intermediate casing 4C and the lower end 4Be of the discharge inner circumferential wall portion 4Bx of the discharge casing 4B may be in contact with each other.

[0055] In any example described in this specification, as in each illustrated embodiment, the upper end of the outer circumferential surface of the inner cylindrical portion 4CL of the intermediate casing 4C may be located in the vicinity of the lower end of the outer circumferential surface of the discharge inner circumferential wall portion 4Bx of the discharge casing 4B in the radial direction. In this case, the step between the inner cylindrical portion 4CL of the intermediate casing 4C and the discharge inner circumferential wall portion 4Bx of the discharge casing 4B in the radial direction can be reduced, and as a result, the fluid F from the first circulating flow path Q can enter the second circulating flow path J more smoothly, thereby improving pump efficiency. Specifically, it is preferable that the radial distance between the upper end of the outer circumferential surface of the inner cylindrical portion 4CL of the intermediate casing 4C and the lower end of the outer circumferential surface of the discharge inner circumferential wall portion 4Bx of the discharge casing 4B be 10 mm or less.

[0056] In any of the examples described herein, the intermediate casing 4C may further have a bottom wall 4CN, as in the embodiments of FIGS. 1 to 4 and 6 to 11. The bottom wall 4CN extends in a direction substantially perpendicular to the axis, on the inner peripheral side of the inner cylindrical portion 4CL. The bottom wall 4CN extends around the entire circumference of the rotary shaft 2, and thus has an annular shape. The bottom wall 4CN may be provided at the lower end of the inner cylinder portion 4CL in the axial direction, as in the embodiments of Figures 1 to 4 and 6 to 11. In this case, the bottom wall 4CN can prevent the fluid F coming out of the impeller 3 from flowing into the inner circumferential side of the inner cylinder, and can accordingly promote the flow into the first circulating flow path Q, thereby improving pump efficiency. And / or, if the inner tube portion 4CL has multiple inner tube segments 4CLP, the bottom wall 4CN may be provided at the lower end of the inner tube segment 4CLP that is located above the lowest inner tube segment 4CLP in the axial direction, as in each embodiment of Figures 10 to 11. The bottom wall 4CN may be configured separately from the inner tube portion 4CL (or the inner tube segment 4CLP), as in the embodiment of Figures 1 to 2, or may be configured integrally with the inner tube portion 4CL (or the inner tube segment 4CLP), as in the embodiments of Figures 3 to 4 and Figures 6 to 11. It is preferable that the outer peripheral edge of the bottom wall 4CN is located on the inner peripheral surface of the inner cylinder portion 4CL (or the inner cylinder segment 4CLP) as in the embodiments of FIGS. The inner peripheral end of the bottom wall 4CN may be located on the outer peripheral surface of the rotating shaft 2 or any member fixed to the rotating shaft 2 (the extension portion 3s of the impeller 3 in each of the embodiments of Figures 1 to 4), as in each of the embodiments of Figures 1 to 4, or may be located away from the outer peripheral surface of the rotating shaft 2 or any member fixed to the rotating shaft 2 (the extension portion 3s of the impeller 3 or the shaft spacer Y in each of the embodiments of Figures 6 to 11). However, the intermediate casing 4C does not have to have the bottom wall 4CN as in the embodiment of FIG.

[0057] In any of the examples described herein, the intermediate casing 4C may further have a top wall 4CP, as in the embodiments of FIGS. The top wall 4CP extends in a direction substantially perpendicular to the axis, on the inner peripheral side of the inner cylindrical portion 4CL. The top wall 4CP extends all around the rotation shaft 2, and thus has an annular shape. The top wall 4CP may be provided at the upper end of the inner cylindrical portion 4CL in the axial direction, as in the embodiments of FIGS. And / or, if the inner tube portion 4CL has multiple inner tube segment members 4CLP, the top wall 4CP may be provided at the upper end of an inner tube segment member 4CLP that is located lower than the uppermost inner tube segment member 4CLP in the axial direction, as in each embodiment of Figures 10 to 11. The top wall 4CP may be configured separately from the inner tube portion 4CL (or the inner tube segment 4CLP), or may be configured integrally with the inner tube portion 4CL (or the inner tube segment 4CLP), as in each embodiment of Figures 10 to 11. It is preferable that the outer peripheral edge of the top wall 4CP is located on the inner peripheral surface of the inner cylinder portion 4CL (or the inner cylinder segment 4CLP), as in the embodiments of FIGS. However, the intermediate casing 4C does not necessarily have to have the top wall 4CP as in the embodiments of FIGS.

[0058] In any of the examples described herein, the intermediate casing 4C may further have one or more protrusions 4CLD, as in the embodiment of FIG. The protrusion 4CLD protrudes from the inner peripheral surface of the inner cylindrical portion 4CL toward the inner peripheral side at an intermediate portion in the axial direction of the inner cylindrical portion 4CL. However, the intermediate casing 4C does not necessarily have to have the protrusion 4CLD as in the embodiments of FIGS. [Industrial Applicability]

[0059] The coolant pump according to the present invention can be suitably used as an immersion type coolant pump. [Explanation of symbols]

[0060] 1 coolant pump 2 rotation axes 3 impeller 3i Impeller inlet 3o Impeller outlet 3s extension part 4 Pump casing 4i Pump suction port 4o Pump outlet 4A Suction casing 4Aw Intake outer wall 4B Discharge casing 4Ba 1st partition wall 4Bb Second partition wall 4Bd Discharge pipe section 4Bw Discharge outer peripheral wall 4Bx Discharge inner peripheral wall 4Be Lower end of inner wall of discharge port 4Bp Annular protrusion S shaft sleeve H Discharge Bush R window Re bottom edge of window E Shaft seal DP discharge flow path J 2nd circulation channel C space G Shaft seal clearance 4C intermediate casing 4CK Split casing member 4cm outer cylinder 4CMP Outer cylinder division parts 4CL inner cylinder part 4CLe Upper end of inner cylinder 4CLP Inner cylinder division member 4CLPk Straight cylindrical member 4CLPw Non-linear cylindrical member 4CLD protrusion 4CG guide member 4CN bottom wall 4CP top wall Q 1st circuit flow path Y-axis spacer O Central axis of the coolant pump F fluid T Tank N nut W washer

Claims

1. A coolant pump, A rotation axis; an impeller fixed to the rotating shaft; a pump casing having a pump suction port and a pump discharge port of the coolant pump; Equipped with The pump casing comprises: a suction casing having the pump suction port and accommodating the impeller therein; a discharge casing having the pump discharge port and disposed above the suction casing; an intermediate casing located between the suction casing and the discharge casing and configured separately from the suction casing and the discharge casing; Equipped with The intermediate casing includes: an outer cylinder portion; an inner cylindrical portion located between the outer cylindrical portion and the rotation shaft in a radial direction; and A coolant pump configured such that the fluid discharged from the impeller passes through a first circulating flow path between the outer cylindrical portion and the inner cylindrical portion of the intermediate casing, and then flows into the discharge casing.

2. The intermediate casing includes: one or more guide members extending spirally within the first circular flow path; 10. The coolant pump of claim 1, further comprising:

3. The coolant pump according to claim 2 , wherein each of the guide members is connected to at least one of the outer cylindrical portion and the inner cylindrical portion.

4. 2. The coolant pump according to claim 1, wherein the outer cylinder portion of the intermediate casing is made up of a plurality of outer cylinder divided members that are formed separately from one another and arranged along the axial direction.

5. 5. The coolant pump according to claim 1, wherein the inner cylindrical portion of the intermediate casing is made up of a plurality of inner cylindrical segment members that are formed separately from one another and arranged along the axial direction.

6. 6. The coolant pump according to claim 5, wherein at least one of the inner-cylinder segments has an outer peripheral surface that extends parallel to the axial direction over the entire axial length.

7. the intermediate casing has a plurality of divided casing members that are formed separately from each other and arranged along the axial direction, Each of the divided casing members includes: an outer cylinder segment that constitutes a part of the outer cylinder portion; an inner cylinder segment that constitutes a part of the inner cylinder portion; one or more guide members that connect the outer cylinder segment and the inner cylinder segment; 3. The coolant pump of claim 2, further comprising:

8. The discharge casing includes: a discharge outer peripheral wall portion; an annular discharge inner peripheral wall portion disposed around the rotation shaft on the inner peripheral side of the discharge outer peripheral wall portion; and 2. The coolant pump according to claim 1, wherein an upper end of the inner cylindrical portion of the intermediate casing is closely opposed to a lower end of the discharge inner circumferential wall portion of the discharge casing in the axial direction.

9. The coolant pump according to claim 1 , wherein at least a portion of an inner circumferential surface of the outer cylindrical portion of the intermediate casing extends parallel to the axial direction.

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