JPH02119550A - Motor having cooling device - Google Patents

Abstract

PURPOSE:To make a motor compact, and to generate a high output by disposing a cooling device into the casing of the motor and connecting the power line of a motor for cooling to the power line of an electric motor in the casing. CONSTITUTION:When an oil pump is driven by a pump motor, oil in an oil reservoir 2b is circulated and made to flow into the oil reservoir 2b again through a path 4c, a pump chamber 2e, an oil cooling chamber 28, a path 2f and a space 2. Oil is scattered on a coil 6d, a rotor 6b, etc., and cools them at that time. Oil absorbs heat and is heated at that time, but the heat of the oil is dissipated to the outside through a casing 1 when oil is circulated and made to flow through a long-sized oil path. The power lines of an electric motor 6, a cooling device and the pump motor are housed integrally into the casing 1. Accordingly, a wheel motor is made extremely compact as a whole.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electric motor equipped with an electric motor cooling device.

[Conventional technology]

Conventionally, wheel motors have often been used as driving means for electric vehicles such as forklifts and golf carts. This wheel motor is an electric motor connected to wheels via a speed reducer, and is provided for each wheel or for each set of wheels.

By the way, in an electric vehicle, the wheels move up and down due to unevenness of the road surface while the vehicle is running, and the wheels rotate left and right when the vehicle turns. For this reason, when an electric motor and a speed reducer for the wheel motor are disposed for each wheel, it is necessary to prevent the vehicle body and the electric motor and speed reducer from interfering with each other during these movements of the wheels. Therefore, their installation space is limited. Therefore, in order to install electric motors and speed reducers within such a limited installation space, it is necessary to make them as small as possible.

On the other hand, in an electric vehicle, since a relatively heavy vehicle body must be moved, the output torque of the electric motor must be considerably high.

However, if an electric motor is to be made small and have high output torque, a large amount of current must be passed through the coils of the electric motor. If a large amount of current is passed through the coil in this way, the coil will generate heat and burn out. Therefore, it is necessary to cool the coil of the electric motor.

Conventionally, cooling devices using oil or air have been used to perform such cooling, but both cooling devices are provided separately from the electric motor.

Therefore, in order to install this cooling device, it is necessary to provide a separate installation space.

Further, power to the electric motor and the pump motor and fan motor in the cooling device is individually supplied from a power source disposed in the vehicle body frame through a large number of power supply lines.

[Problems to be solved by the present invention]

However, it is extremely difficult to provide additional installation space for a cooling device in an electric vehicle where the installation space for an electric motor is limited.

Furthermore, if the cooling device is forcibly installed, there is a risk that the wheels and the cooling device will interfere with each other due to vertical and horizontal movement of the wheels since they are disposed on the vehicle body. Therefore, the movement of the wheels must be restricted.

As described above, it is very difficult to provide both an electric motor and a cooling device within a limited space, and for this reason, it has been almost impossible to increase the output of a small electric motor in the past.

Furthermore, when the electric motor is used as a wheel motor, the electric motor is supported by the vehicle body frame, for example, via a suspension. This suspension forms a relatively movable part that allows relative movement between the vehicle body frame and the wheel motor, and a large number of complicated electric wires such as power lines must be routed through this movable part. .

If a large number of electric wires are disposed in the movable part in this way, wire breakage is likely to occur, resulting in a decrease in reliability.

The present invention has been made in view of these problems, and its purpose is to make the entire structure compact even if a cooling device is installed, so that it does not require a large installation space, and it also has a high output power. The objective is to obtain an electric motor equipped with a cooling device capable of generating .

Another object of the present invention is to obtain an electric motor equipped with a highly reliable cooling device by minimizing the number of electric wires passing through the moving parts as described above.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the invention according to claim 1 is arranged such that the cooling device is disposed within the casing of the electric motor.

A power line of a cooling motor of the cooling device is connected to a power line of an electric motor of the electric motor within the casing.

Further, the invention of claim 2 uses oil as a cooling medium, and for this purpose, an oil reservoir filled with cooling oil is provided in the lower part of the casing, and the oil reservoir is connected to the oil reservoir and the upper and lower coils of the electric motor are connected to each other. A cooling device is configured by providing at least a part of an oil passage that opens into the casing in the casing, and providing an oil pump and a pump motor in the casing to flow cooling oil into the oil passage. I have to. A power line to the pump motor is connected to a power line of the electric motor within the casing.

Furthermore, the invention according to claim 3 is arranged such that a control circuit for controlling the pump motor according to the invention according to claim 2 is provided in the casing.

Further, in a fourth aspect of the invention, the control circuit performs control based on the temperature of the electric motor.

Further, in a fifth aspect of the invention, the control circuit performs control based on the amount of current of the electric motor.

[Function] In the electric motor equipped with the cooling device according to the invention of claim 1 having such a configuration, the cooling device is disposed inside the casing of the electric motor, and the cooling motor of this cooling device is connected to the electric motor through the power supply line of the electric motor. It comes to be driven by a portion of the flowing current. The cooling device cools the electric motor by driving the cooling motor. In this case, the power supply line dedicated to the cooling motor no longer extends outside the casing.

Further, in the invention according to claim 2, when current is supplied from the power line of the electric motor to the pump motor, the pump motor is driven to operate the oil pump. As a result, the oil in the oil reservoir flows in the oil passage, and this oil flows down toward the electric motor from above the electric motor. Therefore, the flowing oil hits the coil of the electric motor and cools this coil. The oil, which has increased in temperature by taking heat from the coil, flows back into the oil sump. The heat of this oil is then dissipated to the outside through the casing. Also in this case, the power supply line dedicated to the pump motor does not extend out from the casing.

Furthermore, in the invention of claim 3, the control circuit controls the pump motor as appropriate based on the control conditions.

Furthermore, in the invention of claim 4, the control circuit controls the pump motor based on the temperature of the electric motor.

Furthermore, in the invention of claim 5, the control circuit controls the pump motor based on the amount of current of the electric motor. In that case, when a large amount of current flows, the motor temperature becomes high, so the present invention is ultimately the same as controlling the electric motor based on its temperature.

In this way, in any of the inventions of claims 1 to 5,
``Since the electric motor fill is reliably cooled by the cooling device, a large current can be passed through the coil. A power line for supplying power to a cooling motor such as a pump motor and a control circuit for controlling the cooling motor are housed within the casing of the motor and do not protrude outside the casing.

In addition, in any of the inventions of claims 1 to 5, the cooling device is integrally provided in the casing of the electric motor, so even if the cooling device is provided, the electric motor does not become so large and the overall size is made compact. Become.

Therefore, the electric motor according to the present invention is small in size yet generates high output torque, and has improved reliability.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

1 to 5 show an embodiment in which an electric motor equipped with a cooling device according to the present invention is applied to a wheel motor of an electric vehicle. FIG. 1 is a vertical sectional view of this embodiment, and FIG. Figure 3 is a vertical cross-sectional view along the line III-III in Figure 2, Figure 4 is a vertical cross-sectional view along line IV-IV in Figure 1, Figure 5 is a vertical cross-sectional view along line IV-IV in Figure 1, FIG. 3 is a power supply circuit diagram of a motor and a pump motor of the cooling device.

As shown in FIGS. 1 and 2, the casing 1 includes a main body 2 and left and right side walls 3.4, which are integrally connected by a large number of bolts 5. As shown in FIGS.

Inside the main body 2, there is provided a space 2a having a substantially circular cross section and an oil reservoir 2b located below and communicating with the space 2a. A large number of cooling fins 2c12 are provided on the outer surface of the main body 2.
c1... is provided. A space 3a having a smaller circular cross section than the circular cross section of the space 2a is provided inside the left side wall portion 3. A large number of cooling fins 3b13b... are also provided on the outer surface of the left side wall portion 3. Right side wall 4
A space 4a with a circular cross section having approximately the same diameter as the space 2a is provided inside the space 2a.

An electric motor 6 is housed within the space 2a of the main body 2. The motor rotation shaft 6a of the electric motor 6 is attached to the side wall 2d of the main body 2.
is rotatably supported by a bearing 7. and,
A rotor 6b of the electric motor 6 is fixed to a motor rotating shaft 6a, and a stator 6c of the electric motor 8 is fixed to an inner wall of the space 2a.

A motor rotation speed sensor 8 is housed in the space 3a of the left side wall 3, and the movable side of the motor rotation speed sensor 8 is fixed to the left end of the motor rotation shaft 6a, and the fixed side is fixed to the left end of the motor rotation shaft 6a. It is fixed to the side wall 2d.

An output rotation shaft 9 is accommodated in the space 4a of the right side wall 4, and a wheel hub 10 is spline-fitted to the output rotation shaft 9, and is fixed by a nut 11 so as not to be movable in the axial direction. This output rotation shaft 9 and wheel hub 10
is rotatably supported by a bearing 12 on the side wall 4b. A wheel 14 supporting a tire 13 is attached to the wheel hub 10 with bolts and nuts 15.

At the left end of the output rotating shaft 9, a concave portion 9a having a circular cross section concentric with the shaft center is formed, and a flange portion 9b that spreads radially is formed.

Further, the right end portion of the motor rotation shaft 6a is fitted into the output rotation shaft 9, and this right end portion is supported by the output rotation shaft 9 in the radial direction by a bearing 16 and in the thrust direction by a bearing 17, respectively.

That is, the motor rotation shaft 6a and the output rotation shaft 9 are disposed on the same axis and can rotate relative to each other.

A carrier 18 is attached near the root of the flange portion 9b. A required number of shafts 19.19, . . . are installed at equal intervals in the circumferential direction between the flange portion 9b and the carrier 18, and planetary gears 20, 20, . ... are each rotatably supported. The planetary gear 20 is disposed between a sun gear 21 formed on the motor rotation shaft 6a and a ring gear 22 fixed to the inner wall of the right side wall portion 4, and is always meshed with both gears 2L22. . And carrier 18, shaft 19, planetary gear 201
The sun gear 21 and the ring gear 22 constitute a planetary gear reduction device that connects the motor rotation shaft 6a and the output rotation shaft 9.

Further, two brake discs 23, 23 are spline-fitted to the peripheral ends of the flange ff19b so as to be slidable only in the axial direction. A flange portion 9b is provided on the inner wall of the right side wall portion 4.
Three friction disks 24.24 are placed opposite the circumferential edge of the
．． 24 is spline-fitted to be slidable only in the axial direction. In this case, the leftmost friction disk 24 is prevented from moving further to the left by a ring-shaped key 25. The brake discs 23 and the friction discs 24 are arranged alternately so as to partially overlap. The end surfaces of the pistons 28a of the brake cylinders 26, 26, .

This brake cylinder 26 is connected to a brake force generating device such as a mask cylinder (not shown). These brake disc 23, friction disc 24, and brake cylinder 26 constitute a brake device.

In this way, the electric motor 6, the planetary gear system, the output rotating shaft 9, and the brake device are housed in one casing.

On the other hand, an oil reservoir 2b provided in the lower part of the main body 2 is communicated with a passage 4c formed in the right side wall portion 4. As shown in FIG. 2, this passage 4C communicates with a pump chamber 2e formed in the main body 2. As is clear from FIG. 3, a blade 27a of an oil pump 27 consisting of a centrifugal pump is disposed in the pump chamber 2e. It is designed to be rotated. Further, the pump chamber 2e communicates with an oil cooling chamber 28 formed across the main body 2 and the left side wall portion 3.

As is clear from FIG. 4, the oil cooling chamber 28 is formed in an annular shape. The upper part of this oil cooling chamber 28 communicates with the upper part of the space 2a of the main body 2 through a passage 2f formed in the main body 2. In this way, a long oil passage communicating from the oil reservoir 2b to the upper part of the space 2a is formed in the main body 2 and the left side wall portion 3. This long oil passage, space 2a,
The oil reservoir 2b is filled with oil.

Furthermore, as shown in FIG. 1, a temperature sensor 31 is attached to the coil 6b. This temperature sensor 31
can be provided at other locations as long as the temperature of the electric motor 6 can be detected.

As shown in FIG. 5, the electric motor 6 is composed of a three-phase motor, and this motor 6 has power lines 32,
2.32, it is connected to a driver 33 that controls the amount of current of the motor 6.

On the other hand, the pump motor 27b is connected to the power line 3 via the rectifier 34.
5.35, it is connected to the power supply line 32 of the electric motor 8. The power line 32 and the power line 35 are connected within the casing 1. Therefore, as shown in FIG. 6, the power line 32 of the electric motor 6 extends outside the casing 1 and is connected to the driver 33, but the power line 35 of the pump motor 27b It does not extend from the casing 1. In other words, the number of power lines extending from the casing 1 is smaller than that of the pump motor 27b. Further, as is clear from FIG. 6, a magnetic pole detection wire 36 is disposed between the electric motor 6 and the power source 33.

The electric motor configured in this manner is directly connected to the tire 13 to constitute a wheel motor 37.

As shown in FIG. 7, a cylindrical turning shaft 38 is provided on the casing 1 of the wheel motor 37 and projects upward, and a cylindrical member 39 for transmitting steering torque is mounted on this turning shaft 38 with a suitable bearing. It is inserted through. This cylindrical member 39 is rotatably supported by a main body frame 40. Therefore, the wheel motor 37 is rotatable around the central axis of the pivot shaft 38 with respect to the main body frame 40, and is also movable up and down. Cylindrical member 39 and wheel motor 3
7 by a torque link 41, and the steering torque is transmitted to the wheel motor 37 by this torque link 41. Further, this torque link 41 is bendable and allows the wheel motor 37 to move up and down. Furthermore, a compression coil spring 42 for buffering is interposed between the cylindrical member 39 and the wheel motor 37. Pivot shaft 38, cylindrical member 39 and spring 4
2 constitutes a suspension. A power supply line 32 and a magnetic pole detection electric wire 36 are disposed through the hole 38a of the pivot shaft 3B.

Next, the operation of this embodiment will be explained.

When an accelerator pedal (not shown) is depressed, a current flows through the coil 6d of the electric motor 6 in an amount corresponding to the amount of depression of the accelerator pedal. As a result, the electric motor θ is driven and the motor rotation shaft 6a is rotated. In that case, the current flowing through the coil 6d is controlled by the driver 33 based on the accelerator depression signal, the output signal from the motor rotation speed sensor 8, and the forward signal from the forward and reverse setting section (not shown), so that the motor rotation The shaft 6a rotates in the forward direction with a set torque.

The rotation of the motor rotation shaft 6a is transmitted to the planetary gear 20 via the sun gear 21, and the planetary gear 20 is transmitted to the shaft 19.
Rotate around the center. Therefore, the planetary gear 20 meshes with the teeth of the ring gear 22 while rotating the motor rotation shaft 6a.
It rotates around its axis. This planetary gear 20
Due to this rotation, the output rotating shaft 9 rotates via the carrier 18 and the flange portion 9b. In that case, the rotation speed of the output rotation shaft 9 is changed by the planetary gear reduction device to the motor rotation shaft 6a.
The rotational speed is decelerated at a predetermined deceleration rate.

When the output rotating shaft 9 rotates, the tire 13 rotates via the wheel hub 10 and the wheel 14. Therefore, the vehicle starts forward. When you press the accelerator further,
Since the torque of the electric motor 6 increases, the vehicle speed increases.

When a brake pedal (not shown) is depressed for braking, braking hydraulic pressure is introduced into the brake cylinder 26. This braking oil pressure moves the piston 28a to the left, and the friction plate 2
Press 4. Therefore, the friction plate 24 comes to pinch the brake disc 23, and the vehicle is braked.

When moving the vehicle backward, the vehicle can be moved backward by setting the forward and reverse setting sections to reverse.

By the way, when a current flows through the coil 6d, the coil 6d generates heat. To deal with this heat generation, the pump motor 27
The oil pump 27 is driven by b. For this reason,
The oil in the oil reservoir 2b flows through the passage 4c1 and the pump chamber 2es.
The oil circulates and flows back into the oil reservoir 2b through the oil cooling chamber 28, the passage 2f, and the space 2a. At this time, the oil is applied to the coil 6d, rotor 6b, etc. and cools them.

In that case, the oil absorbs heat and becomes hot, but this oil heat is dissipated to the outside through the casing 1 as the oil circulates and flows through the long oil passage as described above. In particular, heat within the oil reservoir 2b and the cooling chamber 28 is effectively dissipated by the cooling fins 2C%3b. Then, the oil whose temperature has decreased cools the coil 6d again.

In this way, the cooling device of the present invention is constituted by the oil reservoir 2b, the long path through which oil circulates, the oil pump 27, and the pump motor 27b.

Then, the electric motor 6, the cooling device and the pump motor 2
The power line 35 of 7b is now housed integrally within the casing 1. Therefore, the wheel motor 37 is extremely compact as a whole.

FIG. 8 is an explanatory diagram when the pump motor 27b is finely controlled by the control circuit 43.

As is clear from FIG. 8, a transistor 44 serving as a drive switch for the pump motor 27b is interposed in the power supply line 35. The on/off state of this transistor 44 is controlled by the control circuit 43. As shown in FIG. 6, this control circuit 43 is arranged in the casing 1. This allows the pump motor 27b to be controlled only within the electric motor.

As shown in FIG. 9(A), a thermoswitch 31a is provided in the control circuit 43 as the temperature sensor 31. This thermoswitch 31a closes to turn on the transistor 44 when the temperature of the electric motor 6 reaches a predetermined temperature. Therefore, when the electric motor 6 reaches a predetermined temperature, the pump motor 27b is driven, the oil pump 27 is operated, and oil is applied to the electric motor 6. Thereby, the electric motor 6 is cooled. In that case, since the thermoswitch 31a is simply an on/off switch, the output of the transistor 44 is almost constant, and the 9th
As shown in Figure (B), the pump rotation speed remains constant.

As shown in FIG. 10(A), the temperature sensor 31
As such, a thermistor 31b is provided within the control circuit 43. The resistance of this thermistor 31b decreases linearly as the temperature of the electric motor 6 increases. Therefore, the output of the transistor 44 is
As the temperature of the electric motor 6 increases, the pump rotation speed also increases linearly as the temperature of the electric motor 6 increases, as shown in FIG. 10(B).

FIG. 11(A) shows a case where the control circuit 43 controls the pump motor 27b by duty control.

An output signal from the temperature sensor 31 or the current sensor 31c disposed on the power line 32 of the electric motor 6 is amplified by the amplifier 45 and input to the non-inverting input terminal of the comparator 46. On the other hand, a triangular wave signal from a triangular wave oscillator 47 is input to an inverting input terminal of the comparator 46 . Comparator 46 outputs a duty wave signal, and transistor 44 is controlled by this signal. Therefore, as the amount of current to the electric motor 6 or the temperature of the electric motor 6 increases, the voltage duty ratio increases. That is, the pump motor 27b is controlled by duty control.

This duty control makes it possible to increase the efficiency of the transistor 44. Controlling the pump motor 27b based on the amount of current to the electric motor is performed from the viewpoint that this amount of current is approximately proportional to the temperature, and is substantially equivalent to control based on temperature. It is.

The oil that cools the coil 6d of the electric motor 6 is the bearing 7! 2
．． It also flows into gears 16, 17, gears 20, 21, 22, etc. to lubricate them. By using oil for both cooling and lubrication in this way, space 2a and space 4a
Since there is no need to provide an oil seal between the two, the electric motor becomes even more compact.

In the above embodiment, the entire long oil passage through which oil circulates is provided in the casing 1, but the present invention is not limited to this, and a part of this oil passage is provided in the casing. The other parts can also be formed by tubes. In particular, in cases where the casing has a complicated shape, manufacturing is facilitated by forming the casing with a tube in this manner.

Further, although oil is used as the cooling medium in the above-mentioned embodiments, air may also be used. In that case, a cooling fan may be used instead of the oil pump 27, and the power line of the fan motor of this cooling fan may be connected to the power line 32 of the electric motor 6 within the casing 1.

Furthermore, the electric motor equipped with the cooling device of the present invention can be used not only as a wheel motor of an electric vehicle, but also for all other things that require a small, high-output motor.

[Effects of the Invention] As is clear from the above description, the electric motor equipped with the cooling device according to the present invention has an oil sump, at least a portion of the oil passage,
Since the cooling device consisting of the oil pump and pump motor is integrated into the motor casing,
Even if a cooling device is provided, the electric motor does not become much larger, and the overall size becomes more compact and lightweight. Therefore, no space is required for installing the cooling device, and even when installation space is limited, an electric motor equipped with the cooling device of the present invention can be easily installed.

Furthermore, by being able to install a cooling device, it becomes possible to reliably cool the electric motor. For this reason,
A large current can be passed through the coil. Therefore, the motor can generate high output torque.

Furthermore, since the power line of the pump motor is connected to the power line of the electric motor within the casing, the power line of the pump motor does not extend outside the casing. Therefore, the number of power supply lines extending outside the casing is reduced, improving reliability. In particular, when the electric motor of the present invention is used in an electric vehicle, the number of power lines passing through movable parts such as a suspension is reduced, so reliability is particularly effectively improved.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view of an embodiment in which an electric motor equipped with a cooling device according to the present invention is applied to a wheel motor of an electric vehicle;
Figure 2 is a vertical sectional view taken along line ■-■ in Figure 1, Figure 3 is a sectional view taken along line m-■ in Figure 2, and Figure 4 is a vertical sectional view taken along line IV-■ in Figure 1. 5 is a cross-sectional view, FIG. 5 is a power supply circuit diagram of the electric motor and Hihomp motor, FIG. 6 is a schematic perspective view of the wheel motor connected to a power source, and FIG. 7 is a schematic diagram showing the wheel motor attached to the main body frame. 8 is a power supply circuit diagram of another electric motor and pump motor, FIG. 9 (A) is a control circuit diagram of the pump motor, and FIG. 9 (B) is an explanatory diagram showing the control contents of this control circuit. , FIG. 10(A) is another control circuit diagram of the pump motor, FIG. 10(B) is an explanatory diagram showing the control contents of this control circuit, and FIG. 11(A) is still another control circuit of the pump motor. 11(B) are explanatory diagrams showing the control contents of this control circuit. 1... Casing, 2b... Oil reservoir, 2c... Cooling fin, 2e... Pump chamber, 2f... Passage, 3b
... Cooling fin, 4c... Passage, 6... Electric motor, 27... Oil pump, 27b... Pump motor (cooling motor), 28... Oil cooling chamber, 31...
Temperature sensor, 31C... Current sensor, 32... Electric motor power line, 35... Pump motor power line, 4
3...Control circuit. Figure 5 Figure 6 Figure 7 Figure 9 ('A)

Claims (5)

[Claims] (1) An electric motor equipped with a cooling device for cooling an electric motor housed in a casing, the cooling device being disposed in the casing, and a power line for the cooling motor of the cooling device being An electric motor equipped with a cooling device, the cooling device being connected to a power line of the electric motor within the casing. (2) The cooling device includes an oil sump provided at a lower part of the casing and filled with cooling oil, and at least a portion of which is formed in the casing and communicates with the oil sump, and the casing above the electric motor. It consists of an oil passage that opens into the casing, an oil pump that is provided in the casing to flow cooling oil into the oil passage, and a pump motor that drives the oil pump, and a power line for the pump motor is connected to the inside of the casing. 2. An electric motor equipped with a cooling device according to claim 1, wherein the cooling device is connected to a power supply line of the electric motor. (3) The electric motor equipped with a cooling device according to claim 2, wherein a control circuit for controlling the pump motor is further disposed in the casing. (4) The electric motor equipped with a cooling device according to claim 3, wherein the control circuit controls the pump motor according to the temperature of the electric motor. (5) Claim 3, wherein the control circuit controls the pump motor according to the amount of current of the electric motor.
Electric motor with cooling device as described.