DE102010025650B4 - engine cooling device - Google Patents

Abstract

Engine cooling device comprising:
a first element (20) in which a stator (1) with windings (12) is provided;
a second member (30) having a cylindrical inner peripheral surface and adapted to be seated on an outer peripheral surface of the first member (20); and
a coolant channel (PA1; PA2; PA3) provided in an installation section formed between the first and second members (20, 30), a cooling medium flowing from a first axial end face to a second axial end face of the installation section,
wherein the coolant channel (PA1; PA2; PA3) comprises:
a plurality of helical passages (PA11; PA12; PA13) spirally extending in the circumferential direction and from the first axial face to the second axial face of the mounting portion,
wherein the plurality of spiral channels (PA11; PA12; PA13) are arranged side by side such that the channels (PA11; PA12; PA13) do not intersect each other, wherein the plurality of spiral channels (PA11; PA12; PA13) are arranged substantially parallel to each other are,
wherein the plurality of spiral channels (PA11; PA12; PA13) is formed by a multiple spiral groove (21),
wherein the coolant passage (PA1; PA2; PA3) further comprises two annular passages (PA2; PA3) each extending over the entire circumference at a first axial end portion and a second axial end portion of the installation portion between the first and second members (20, 30 ) are formed on opposite sides of the plurality of spiral channels (PA11; PA12; PA13),
wherein one of the two annular passages (PA2; PA3) connects an inlet portion (PA4) into which the cooling medium flows to first axial end portions of the plurality of spiral passages (PA11; PA12; PA13), and the other of the two annular passages (PA2; PA3) connects an outlet section (PA5), from which the cooling medium flows, to second axial end sections of the plurality of spiral channels,
the annular channels (PA2; PA3) being formed by annular grooves (22, 23),
wherein the inlet portion (PA4) and the outlet portion (PA5) are formed by a plurality of through holes (31, 32) formed thereto are to respectively extend through the second member (20) along a radial direction.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a motor cooling device for cooling an electric motor by a cooling medium flowing around the motor.

2. Description of Related Art

Conventionally, a motor cooling device is known in which a coolant passage is provided in the inner peripheral surface of a cylindrical case surrounding the outer periphery of a stator core to cool the electric motor. At the in the document JP 2005 - 204 496 A In the device described, a spiral groove is formed as a coolant channel in the inner peripheral surface of the housing so as to extend from one axial end to the other, from this back to the one axial end and from this in turn to the other axial end.

However, at the in the document JP 2005 - 204 496 A described device, the length of the spiral groove is long since it is formed between the one and the other axial end portion. As a result, the pressure loss becomes higher, and it is therefore difficult to feed the required amount of refrigerant through the refrigerant passage. In addition, since the temperature of the coolant gradually increases in the flow direction of the coolant, a sufficient cooling effect can no longer be obtained in the downstream portion of the passage when the length of the coolant passages is long.

From the document JP H10-336 965 A a cooling jacket arrangement is known which seeks to avoid gas and air formation on a top side within the cooling jacket by means of a special arrangement of inlet and outlet openings. The document DE 297 15 079 U1 further teaches locating coil springs within a heat exchanger shell, with the spaces between the coils of the coil springs each defining fluid passages. Other engine cooling devices are from the publication WO 2007 / 051 681 A1 , from the document JP 2004 - 023 816 A, from the reference KR 10 1 047 643 B1 and from the document JP H08 - 111 966 A known.

SUMMARY OF THE INVENTION

According to the invention, an engine cooling device according to claim 1 is provided.

character list

• 1 eine Schnittansicht einer Konfiguration einer Motorkühlvorrichtung gemäß einer Ausführungsform der vorliegenden Erfindung;
• 2 eine perspektivische Ansicht eines Kühlmantels und eines Kühlgehäuses, die die Motorkühlvorrichtung gemäß der Ausführungsform der vorliegenden Erfindung bilden;
• 3 die Ansicht einer Abwicklung einer Außenumfangsfläche eines in 2 dargestellten Kühlmantels;
• 4A eine vergrößerte Schnittansicht einer eingängigen Rille eines spiralförmigen Kanals;
• 4B eine vergrößerte Schnittansicht einer dreigängigen Rille eines spiralförmigen Kanals;
• 4C eine vergrößerte Schnittansicht einer achtgängigen Rille eines spiralförmigen Kanals.

The objects, features and advantages of the present invention will be understood from the following description of the preferred embodiments taken in connection with the accompanying drawings; show it:

• 1 12 is a sectional view showing a configuration of an engine cooling device according to an embodiment of the present invention;
• 2 Fig. 14 is a perspective view of a cooling jacket and a cooling case constituting the engine cooling device according to the embodiment of the present invention;
• 3 the view of a development of an outer peripheral surface of an in 2 illustrated cooling jacket;
• 4A Figure 14 is an enlarged sectional view of a single start groove of a helical channel;
• 4B an enlarged sectional view of a three-start groove of a spiral channel;
• 4C an enlarged sectional view of an eight-start groove of a spiral canal.

DETAILED DESCRIPTION

An embodiment of the present invention is described below with reference to FIG 1 until 4C described. 1 12 is a schematic configuration diagram of an electric motor M to which a motor cooling device according to the embodiment of the invention is applied. The motor M has a cylindrical stator 1 and a rotor (not shown) rotatably supported in the stator 1. As shown in FIG.

The stator 1 has a stator core 11 formed of laminated magnetic bodies such as magnetic steel sheets, and a winding 12 wound around the stator core 11 as a compact or distributed winding. The stator core 11 and the coil 12 are coated with a resin 13 in which a material having high thermal conductivity is mixed. A voltage supply line 14 is led out of the end of the stator 1 . An external control current is supplied to the winding 12 via the power supply line 14 to generate a rotating magnetic field around the rotor to cause the rotor to rotate.

Since this type of motor M generates heat due to iron loss in the stator core 11 and copper loss in the winding 12, the motor M needs to be cooled to reduce heat generation. Especially when the motor M serves as a spindle motor of a machine tool and the spindle When the shaft of the machine tool is deformed due to heat transfer, the thermal deformation degrades the machining precision, so it is imperative to reduce the heat generation of the motor M. In the embodiment of the present invention, a cooling device 2 for cooling the motor M is constructed as follows.

The cooling device 2 has a substantially cylindrical cooling jacket 20 fitted on the outer peripheral surface of the stator 1 and a cooling case 30 fitted on the outer peripheral surface of the cooling jacket 20 . 2 14 is a perspective view of cooling case 30 and cooling jacket 20 removed from cooling case 30. Insofar as cooling case 30 has a cylindrical inner peripheral surface and defines a cavity therein for receiving cooling jacket 20, the external shape of cooling case 30 need not necessarily be cylindrical. Namely, the outer shape of the cooling case may be polygonal, e.g. B. when the motor M is used for the spindle shaft of the machine tool, the cooling housing can be part of the structure supporting the spindle.

As in 2 1, a spiral groove 21 is formed in the outer peripheral surface of the cooling jacket 20. As shown in FIG. The spiral groove extends spirally in the circumferential direction and from a first axial end surface to a second axial end surface of the cooling jacket 20. In the outer peripheral surface of the cooling jacket 20 on both sides of the spiral groove 21, annular grooves 22 and 23 are formed in the axial direction. The annular grooves 22 and 23 extend over the entire circumference of the cooling jacket. Further, grooves 24 and 25 for attaching O-rings are formed on the outside of the annular grooves 22 and 23 in the axial direction. These grooves 21 to 25 z. B. machined chipped on a lathe with milling shaft for complex workpieces. It should be noted that the depth of the annular grooves 22 and 23 is greater than that of the spiral groove 21 in 1 and identical to that of the spiral groove 21 in 2 .

A plurality of (three in the illustrated embodiment) through holes 31 and 32 are formed in the first and second axial end faces of the cooling case 30 and arranged in the circumferential direction. When the cooling case 30 is mounted on the cooling jacket 20, the location of each of these through holes 31 and 32 corresponds to the location of each of the spiral grooves 22 and 23, respectively. The through holes 31 and 32 form an inlet portion PA4 and an outlet portion PA5, respectively, of a coolant passage described below.

The cooling jacket 20 is fixedly attached to the outer peripheral surface of the stator 1, z. B. by a press fit. The cooling housing 30 is likewise fixedly attached to the outer peripheral surface of the cooling jacket 20, e.g. B. by a press fit. It should be noted that the cooling housing 30 may be fitted on the outer peripheral surface of the cooling jacket 20 with a loose fit or an interference fit for ease of assembly.

As in 1 Illustrated is the coolant passage, with the cooling case 30 mounted on the cooling jacket 20, in the installation portion defined between the cooling jacket 20 and the cooling case 30, from the first axial end face to the second axial end face by the inner peripheral surface of the cooling case 30 and the grooves 21 to 23 of the Cooling jacket 20 formed. Namely, a spiral passage PA1 is formed by the spiral groove 21 of the cooling jacket 20, and the annular passages PA2 and PA3 are formed by the annular grooves 22 and 23, respectively.

A coolant supply source (not shown), such as a pump, is connected to each inlet portion PA4 (through-holes 31) of the coolant channel via piping. A coolant collector (not shown) such as a tank is connected to each outlet portion PA5 (through holes 32) via piping. Therefore, when a coolant is supplied from the outside into the coolant passage via the inlet portion PA4, the coolant flows into the annular passage PA2, the spiral passage PA1 and the annular passage PA3 in sequence and is discharged to the outside via the outlet portion PA5. The flowing coolant absorbs heat from the surface of the cooling jacket 20, whereby the motor M is cooled. It should be noted that a plurality of inlet portions PA4 and a plurality of outlet portions PA5 are connected to the coolant supply source and the coolant collector, respectively, e.g. B. are connected via manifolds, so that the refrigerant is evenly supplied to each inlet section PA4 and discharged from each outlet section PA5.

In the cooling device constructed as explained above, the cooling effect increases as the amount of the coolant increases and the surface area of the coolant passage serving as the fin portion increases. It is possible to simply increase the surface area of the coolant channel in that the spiral channel PA1 z. B. is formed of a single-start groove to thereby reduce the channel pitch p (pitch between adjacent channels) or to make the spiral groove 21 deeper.

However, if the passage pitch p is reduced, the pressure loss increases and consequently it is difficult to supply the required amount of refrigerant. In addition, in order to make the spiral groove 21 deeper, the cooling jacket 20 must be sufficiently thick, which not only makes it impossible to miniaturize the motor, but also increases the amount of chipped material to be removed when machining the groove, resulting in an increase in the manufacturing costs. In view of these problems, in the embodiment of the present invention, as described below, a plurality of laterally juxtaposed spiral grooves 21 (multi-start spiral groove) are machined in the surface of the cooling jacket 20 in such a manner that these grooves do not intersect with each other, so that the spiral passage PA1 from channels arranged side by side.

3 FIG. 12 is a development view of the outer peripheral surface of the cooling jacket 20, schematically showing the flow of coolant, in which three-start grooves of the spiral passages PA11 to PA13 are machined in the outer peripheral surface of the cooling jacket 20. FIG. These spiral channels PA11 to PA13 are formed substantially in parallel, and the channel width w1, the channel depth (d2 in 4B) , the curvature of the channel (helical curvature) and the distance between adjacent channels (channel pitch p) of the channels PA11 to PA13 are all constant. In other words, the channels PA11 to PA13 have an identical shape and start ends with e.g. B. 120 ° different phases. The spiral channels PA11 to PA13 are densely distributed over the entire surface of the cooling jacket. It should be noted that in the illustrated embodiment, the channel width w1 and the width w2 of the land portion formed between adjacent channels are substantially identical, however, w1 may be greater or less than w2.

In 3 The refrigerant introduced into the annular passage PA2 via the inlet portion PA4 branches into the spiral passages PA11 to PA13 and flows along the respective spiral passages PA11 to PA13 as indicated by the solid line, dashed line and chain line arrows, respectively. Thereafter, the coolant flows join at the annular passage PA3 and are discharged from the outlet section PA5.

The motor M is cooled by these coolant flows. In the embodiment of the present invention, the spiral passages PA11 to PA13 are arranged side by side. Thus, if the passages PA11 to PA13 are densely distributed on the surface of the cooling jacket 20 as in 3 shown, the channel length of the individual channels PA11 to PA13 can be shortened and thus a sufficient cooling effect can be achieved over the entire channel.

Assuming that the flow channel area of the individual channels PA11 to PA13 is S1 or S3, the total flow channel area S is represented by S=S1+S2+S3. Therefore, a sufficient flow passage area S can be obtained, and consequently it is possible to reduce the passage pitch p without reducing the amount of coolant to be supplied. As the channel pitch p becomes smaller, the entire surface of the coolant channel increases, so that the cooling effect can be increased.

The 4A until 4C are enlarged sectional views of the spiral passage PA1. The 4A until 4C show one-start, three-start and eight-start spiral grooves of the channels PA1. Assuming that the channel areas in these figures are Sa, Sb, and Sc, respectively, the total channel areas S are equal to Sa, 3 times Sb, and 8 times Sc, respectively. In the 4A until 4C the entire channel surfaces S are almost identical to one another. The three-start groove at channel pitch p2 is about half that of the single-start groove at channel pitch p1, and the eight-start groove at channel pitch p3 is about one-third that of the single-start groove at channel pitch p1. Further, the groove depths d1 to d3 in the respective figures are d1>d2>d3, and the groove depth d3 of the eight-start groove is about half the groove depth d1 of the single-start groove.

Relative to the surface area of the entire channel of the single-start groove and the amount of material to be machined to form the same channel, the surface area of the entire channel of the three-start groove and the amount of material to be machined are about 1.2 times and that, respectively 0.7 times, and the surface area of the entire channel of the eight-start groove and the amount of material to be machined are about 1.2 times and 0.4 times, respectively. Therefore, with the coolant passage PA1 composed of multi-start spiral grooves, it is possible not only to increase the surface area without changing the total area S of the flow passage but also to reduce the amount of material to be machined. As a result, the wear of a milling tool and the machining time are reduced, whereby the manufacturing cost can be reduced. The number of threads constituting the spiral groove 21 must be more than one and can be any number except three and eight, and can be determined depending on the required cooling capacity and the manufacturing cost.

1. (1) Eine Mehrzahl spiralförmiger Rillen 21 wird so in die Außenumfangsfläche des Kühlmantels 20 gefräst, dass die Rillen sich nicht gegenseitig überschneiden, und die spiralförmigen Kanäle PA11 bis PA13 sind seitlich nebeneinander angeordnet. Aufgrund dieser Konfiguration ist es möglich, die Oberfläche des Kühlmittelkanals zu vergrößern, ohne die Kanallänge der einzelnen spiralförmigen Kanäle PA11 bis PA13 zu verlängern, so dass die Kühlwirkung verstärkt werden kann. Wenn nämlich der spiralförmige Kanal PA1 mit einer kleinen Kanalteilung p aus einer einzigen spiralförmigen Kanalrille 21 (einer durchgehenden Rille) gebildet wird, wird die Gesamtlänge des Kühlmittelkanals lang, wodurch der Druckverlust höher wird. Als Ergebnis wird es schwierig, die erforderliche Kühlmittelmenge zuzuführen, so dass keine ausreichende Kühlwirkung für den Motor M erzielt werden kann. Da im Gegensatz dazu bei der Ausführungsform eine Mehrzahl spiralförmiger Kanäle PA11 bis PA13 seitlich nebeneinander angeordnet sind, wird der Druckverlust im Kanal verringert, während eine ausreichende Strömungskanalfläche bereitgestellt ist, so dass folglich eine ausreichende Kühlwirkung für den Motor M erzielt werden kann.
2. (2) Da die spiralförmigen Kanäle PA11 bis PA13 im Wesentlichen parallel zueinander angeordnet sind, ist der spiralförmige Kanal PA1 über die Außenumfangsfläche des Kühlmantels 20 gleichmäßig angeordnet, so dass der gesamte Motor in wirksamer Weise gekühlt werden kann.
3. (3) Die ringförmigen Kanäle PA2 und PA3 sind an beiden Seiten der spiralförmigen Kanäle PA11 bis PA13 in axialer Richtung vorgesehen. Ferner sind die Einlassabschnitte PA4 und die Auslassabschnitte PA5 des Kühlmittels mit dem ersten axialen Endabschnitt und dem zweiten axialen Endabschnitt der spiralförmigen Kanäle PA11 bis PA13 über die ringförmigen Kanäle PA2 bzw. PA3 verbunden. Aufgrund dieser Konfiguration kann das Kühlmittel gleichmäßig in die entsprechenden spiralförmigen Kanäle PA11 bis PA13 eingespeist werden, so dass eine ausreichende Kühlwirkung erzielt werden kann.
4. (4) Da eine Mehrzahl Einlassabschnitte PA4 und Auslassabschnitte PA5 des Kühlmittels in Umfangsrichtung im Kühlgehäuse 30 angeordnet sind, kann eine große Kühlmittelmenge zur Oberfläche des Kühlmantels 20 gefördert werden.

According to the embodiment, the following functions and effects can be obtained.

1. (1) A plurality of spiral grooves 21 are milled in the outer peripheral surface of the water jacket 20 so that the grooves do not cross each other, and the spiral passages PA11 to PA13 are arranged side by side. Due to this configuration, it is possible to increase the surface area of the coolant channel without increasing the channel length of each spiral channel PA11 to PA13, so that the cooling effect can be enhanced. That is, if the spiral passage PA1 having a small passage pitch p is formed from a single spiral passage groove 21 (a continuous groove), the total length of the refrigerant passage becomes long, thereby increasing the pressure loss. As a result, it becomes difficult to supply the necessary amount of coolant, so that a sufficient cooling effect for the motor M cannot be obtained. In contrast, in the embodiment, since a plurality of spiral passages PA11 to PA13 are arranged side by side, the pressure loss in the passage is reduced while providing a sufficient flow passage area, and consequently a sufficient cooling effect for the motor M can be obtained.
2. (2) Since the spiral passages PA11 to PA13 are arranged substantially parallel to each other, the spiral passage PA1 is evenly arranged over the outer peripheral surface of the cooling jacket 20, so that the entire engine can be efficiently cooled.
3. (3) The annular passages PA2 and PA3 are provided on both sides of the spiral passages PA11 to PA13 in the axial direction. Further, the inlet portions PA4 and the outlet portions PA5 of the coolant are connected to the first axial end portion and the second axial end portion of the spiral passages PA11 to PA13 via the annular passages PA2 and PA3, respectively. Due to this configuration, the coolant can be smoothly fed into the respective spiral passages PA11 to PA13, so that a sufficient cooling effect can be obtained.
4. (4) Since a plurality of inlet portions PA4 and outlet portions PA5 of the coolant are circumferentially arranged in the cooling case 30, a large amount of coolant can be discharged to the surface of the cooling jacket 20.

In 1 For example, the annular passages PA2 and PA3 are formed deeper than the spiral passage PA1, to increase the flow passage area of the annular passages PA2 and PA3 in order not to increase the pressure loss in the annular passages PA2 and PA3. However, when there is no need to consider the pressure loss, it is preferable from the viewpoint of manufacturing cost to form the passages PA1 to PA3 with the same depth as in FIG 2 is shown.

In the above embodiment, the grooves 21 to 23 are machined in the outer peripheral surface of the cooling jacket 20 as the coolant passages PA1 to PA3. Alternatively, grooves as a coolant channel may be machined in the inner peripheral surface of the cooling case 30 or in both the outer peripheral surface of the cooling jacket 20 and the inner peripheral surface of the cooling case 30 . Namely, as long as a plurality of spiral passages PA1 are formed side by side in the installation portion between the cooling jacket 20 as the first member and the cooling case 30 as the second member, the shapes of the inner peripheral surface of the cooling jacket 20 and the outer peripheral surface of the cooling case 30 are not limited to specific shapes. Alternatively, the stator 1 can serve as the first member, and then the spiral passage PA1 is formed in the outer peripheral surface of the stator 1 .

Alternatively, a plurality of the spiral coolant passages PA<b>1 are formed without forming the grooves in the inner peripheral surface of the cooling jacket 20 and the outer peripheral surface of the cooling case 30 . For example, a plurality of channel members in the form of a coil may be inserted between the inner peripheral surface of the cooling jacket 20 and the outer peripheral surface of the cooling case 30, the channel members having different phases from each other so that a plurality of spiral coolant channels PA1 are formed from the inner peripheral surface of the cooling jacket 20, the outer peripheral surface of the cooling case 30 and the channel elements is defined. However, when the channel members are provided independently, the thermal resistance at the contact surfaces between the channel members and the cooling jacket 20 increases, so that the thermal conductivity decreases. Therefore, it is preferable to form the coolant passage in the cooling jacket 20 by forming grooves.

The spiral groove 21 can be formed by cutting, grinding, hobbing, laser machining, electrical discharge machining or the like, or it can be formed by casting. However, when the cooling jacket 20 having the spiral groove 21 is formed by casting, cracks and voids tend to form. From the viewpoint of product reliability, therefore, it is preferable to form the groove by cutting a cylindrical tubular member.

In the above embodiment, the annular passages PA2 and PA3 are provided on both sides of the spiral passage PA1 in the axial direction, and the coolant is supplied to and discharged from the spiral passage PA1 through the annular passages PA2 and PA3. Alternatively, the coolant can be fed into or removed from the spiral-shaped channel PA1 directly, ie not through the annular channels PA2 and PA3. In the above embodiment, the outlet/inlet sections PA4 and PA5 of the coolant are provided in the cooling case 30 . However, the number, shape and arrangement etc. of the outlet/inlet sections PA4 and PA5 can be modified if desired. The cooling medium flowing into the coolant passage is not limited to liquid such as water or oil, but may be gas.

The cooling device described above can be applied not only to a motor M for driving a spindle shaft of a machine tool but also to a motor M of devices other than a machine tool.

According to the present invention, a plurality of spiral channels as coolant channels are formed side by side in the radially outer side of the stator. Therefore, the length of each coolant passage is shortened, and consequently the cooling effect by the flow of the coolant can be enhanced.

Although the invention has been described in terms of certain preferred embodiments, it will be understood by those skilled in the art that various changes or modifications can be made therein without departing from the scope of the following claims.

Claims (1)

Engine cooling device comprising: a first element (20) in which a stator (1) with windings (12) is provided; a second member (30) having a cylindrical inner peripheral surface and adapted to be seated on an outer peripheral surface of the first member (20); and a coolant channel (PA1; PA2; PA3) provided in an installation section formed between the first and second members (20, 30), a cooling medium flowing from a first axial end face to a second axial end face of the installation section, wherein the coolant channel (PA1; PA2; PA3) comprises: a plurality of helical passages (PA11; PA12; PA13) spirally extending in the circumferential direction and from the first axial face to the second axial face of the mounting portion, wherein the plurality of spiral channels (PA11; PA12; PA13) are arranged side by side such that the channels (PA11; PA12; PA13) do not intersect each other, wherein the plurality of spiral channels (PA11; PA12; PA13) are arranged substantially parallel to each other are, wherein the plurality of spiral channels (PA11; PA12; PA13) is formed by a multiple spiral groove (21), wherein the coolant passage (PA1; PA2; PA3) further comprises two annular passages (PA2; PA3) each extending over the entire circumference at a first axial end portion and a second axial end portion of the installation portion between the first and second members (20, 30 ) are formed on opposite sides of the plurality of spiral channels (PA11; PA12; PA13), wherein one of the two annular passages (PA2; PA3) connects an inlet portion (PA4) into which the cooling medium flows to first axial end portions of the plurality of spiral passages (PA11; PA12; PA13), and the other of the two annular passages (PA2; PA3) connects an outlet section (PA5), from which the cooling medium flows, to second axial end sections of the plurality of spiral channels, the annular channels (PA2; PA3) being formed by annular grooves (22, 23), wherein the inlet portion (PA4) and the outlet portion (PA5) are formed by a plurality of through holes (31, 32) adapted to respectively extend through the second member (20) along a radial direction.

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