JP4516878B2 - Axle device - Google Patents

Description

  The present invention relates to an axle device in which a differential and a wet multi-plate brake are incorporated in an axle housing, and more particularly, to an axle device in which a wet multi-plate brake is incorporated at both ends of the axle housing.

  In a differential of a vehicle such as an automobile, a system in which a differential rotating portion, a gear meshing portion, or the like is oil-lubricated with lubricating oil stored in a housing is employed. When the vehicle is running, the temperature of the lubricating oil rises due to the heat generated in the rotating part and the gear meshing part.However, in the case of long-distance running and high-speed running, the temperature of the lubricating oil rises extremely, and the function of the lubricating oil There is a risk that problems such as reduction and seizure will occur. As means for suppressing such a temperature rise of the lubricating oil, it is known to cool the lubricating oil in the housing by circulating it outside (see, for example, Patent Document 1).

  In the lubricating oil cooling device disclosed in Patent Document 1, an oil pump is disposed in an upper portion of a differential in a housing, and the oil pump operates in conjunction with the differential when driven. It is configured. When the differential is driven, the oil pump is actuated, the lubricating oil in the housing is taken out and cooled by the oil cooler, and then is exposed to the lubricating part such as the differential rotating part and the gear meshing part. It is configured to be introduced into the housing through a return passage provided in the manner described above.

  By the way, in a large construction vehicle such as a wheel loader, for example, a propeller shaft from a transmission (drive unit side) is linked to an input side of an axle device such as a front axle or a rear axle. The axle device is configured such that a differential, an axle shaft extending to the left and right of the differential, and a wet multi-plate brake are incorporated in an axle housing. In the axle device having such a configuration, the wet multi-plate brake is incorporated in both ends of the axle housing, and the differential and each wet multi-plate brake are in communication with each other by the lubricating oil stored in the axle housing. Oil lubrication may occur. In a construction vehicle equipped with an axle device having such a configuration, if braking is frequently used in a high temperature environment, the frictional heat generated at the pressure contact portion of the wet multi-plate brake becomes excessive, so that There is a risk that the temperature of the lubricating oil will rise more than expected, leading to problems such as deterioration of the function of the lubricating oil and seizure of the pressure contact portion of the brake. This is because the differential and the wet multi-plate brake are in communication with each other, but they are separated from each other, so that the lubricating oil is not circulated between them, and the lubricating oil around the wet multi-plate brake is difficult to cool. It is thought to be caused by.

  When the lubricating oil cooling device disclosed in Patent Document 1 is applied to such an axle device, the lubricating oil cooled outside the housing passes through a return passage provided facing the differential lubricating portion. Thus, the lubricating oil around the differential is cooled. However, as described above, since the differential and the wet multi-plate brake are separated from each other, the lubricating oil around the differential and the lubricating oil around the wet multi-plate brake may not be properly circulated. There is a risk that problems such as seizure of the pressure contact portion of the plate brake may occur. Further, in the lubricating oil cooling apparatus, since an oil pump interlocking with the differential is disposed in the housing, the structure in the housing is complicated, and the manufacturing cost tends to increase.

JP 2001-182808 A

  The present invention has been conceived under such circumstances, and wet multi-plate brakes are built in both ends of an axle housing that accommodates the differential, and the differential and each wet multi-plate brake are included in the axle housing. In an axle device that is oil-lubricated in a communicating state, it is possible to efficiently cool the lubricating oil around the wet multi-plate brake and improve the durability of the wet multi-plate brake while simplifying the structure It is an object to provide an axle device.

  In order to solve the above problems, the present invention takes the following technical means.

An axle apparatus provided by the present invention includes an axle housing that houses a differential and an axle shaft that extends from the differential to the left and right, and has wet multi-plate brakes at both ends of the axle housing. In the housing, the differential and each of the wet multi-plate brakes are oil-lubricated in a communication state. In the axle device, the axle housing has a lubricating oil outlet port near the differential, and lubricating oil is introduced at both ends. ports are provided respectively, in the lubricating oil outlet port connected to the conduit and the lubricating oil introduced connected conduit to a port, the oil pump are cooperative, the oil pump, Force serial be actuated by a hydraulic motor which rotates the supply of the working oil pressure for the wet multi-disc brake, by the operation of the oil pump, the lubricating oil lubricating oil derived from the outlet port through the lubricating oil introducing port In particular, it is configured to be introduced into the axle housing.

  According to the axle device having such a configuration, the lubricating oil cooled through the pipe line outside the axle housing is introduced into the axle housing via the lubricating oil introduction ports provided at both ends of the axle housing. Therefore, the lubricating oil around the wet multi-plate brake built in both ends of the axle housing is efficiently cooled. Therefore, even if the frictional heat generated at the pressure contact part of the wet multi-plate brake becomes excessive due to heavy braking, it is avoided that the temperature of the lubricating oil around the wet multi-plate brake is excessively increased. The As a result, defects such as seizure of the pressure contact portion of the wet multi-plate brake are appropriately prevented, and the durability of the wet multi-plate brake is improved.

  Further, in the axle device configured as described above, the operating source of the oil pump for feeding the lubricating oil is the operating hydraulic pressure (excess hydraulic pressure) for the service brake already installed in the vehicle. There is no need to provide it. In addition, when the working hydraulic pressure for the service brake is used as a drive source of the oil pump, the arrangement location of the oil pump is not restricted and the degree of design freedom can be increased. Therefore, in the axle device according to the present invention, the structure can be simplified as compared with the case where an oil pump interlocking with a differential is provided in the housing as in the prior art.

  In a preferred embodiment of the present invention, a final reduction gear is further arranged at both ends of the axle housing.

  In a preferred embodiment of the present invention, the hydraulic pressure for operating the oil pump is supplied via a charging valve that controls pressure accumulation in the accumulator for the wet multi-plate brake.

  According to such a configuration, when the hydraulic oil is not supplied to the accumulator by using the charging valve provided in the vehicle as the hydraulic oil circuit of the wet multi-plate brake which is a service brake, the operation is performed. The surplus hydraulic pressure can be effectively supplied as the operating source of the oil pump.

  In a preferred embodiment of the present invention, a flow divider is provided between the lubricating oil introduction port and the oil pump to evenly distribute the lubricating oil sent from the oil pump.

  According to such a configuration, the supply amount of the lubricating oil supplied into the axle housing via the lubricating oil introduction ports provided at both ends of the axle housing is the same or substantially the same. Therefore, the lubricating oil around the wet multi-plate brake is cooled in a balanced manner, which is suitable for improving the durability of the wet multi-plate brake.

  In a preferred embodiment of the present invention, the hydraulic pressure for operating the oil pump is supplied via hydraulic pressure supply control means for controlling the supply amount according to the temperature of the lubricating oil around the wet multi-plate brake. Done.

  According to such a configuration, the rotation of the oil pump can be controlled in accordance with the temperature of the lubricating oil around the wet multi-plate brake, and the axle housing is connected via the lubricating oil introduction port as the temperature of the lubricating oil increases. The supply amount of the cooled lubricating oil supplied into the inside can be increased. Therefore, it is more suitable for efficiently cooling the lubricating oil around the wet multi-plate brake.

  Other features and advantages of the present invention will become more apparent from the following description of the embodiments of the invention.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings. For convenience of explanation, the vertical and horizontal directions are specified with reference to FIG.

  1 and 2 show an example of an axle device according to the present invention. FIG. 1 is a schematic configuration diagram including a hydraulic circuit of the axle device A of the present embodiment. FIG. 2 is a partially cutaway cross-sectional view of the main part of the axle device A. FIG. The axle device A of the present embodiment is used as an axle device such as a front axle and a rear axle in a large construction vehicle such as a wheel loader. The axle device A includes a differential 1, an axle shaft 2 that extends to the left and right of the differential 1, a wet multi-plate brake 3, a final reduction gear 4, an axle housing 5 that accommodates these, and a lubricating oil cooling mechanism 6.

  The differential 1 is incorporated in the central portion 5 a of the axle housing 5. In the differential 1, a pair of left and right powers transmitted from a transmission via a propeller shaft (both not shown) are rotatable about the same rotation axis H via a gear mechanism (a reduction gear mechanism or a differential mechanism). It is configured to be transmitted to the axle shaft 2. The power transmitted to the axle shaft 2 is configured to be transmitted to the wheel hub 18 via the final reduction gear 4 at the end of the axle shaft 2. A cap 19 is attached to the end surface of the wheel hub 18.

  The final reduction gear 4 is configured to include a planetary gear mechanism, and is disposed at both end portions 5 b and 5 b of the axle housing 5. More specifically, as shown in FIG. 2, a cylindrical shaft body 5 c that pivotally supports the end portion of the axle shaft 2 is fixedly connected to the end portion 5 b of the axle housing 5, and is connected to the end portion of the cylindrical shaft body 5 c. A gear hub 5d is fixedly connected, and the final reduction gear 4 is disposed inside the gear hub 5d.

  The wet multi-plate brake 3 is incorporated in both end portions 5 b and 5 b of the axle housing 5. As shown in FIG. 2, the wet multi-plate brake 3 includes a plurality (eight) of disks 30, a plurality (nine) of plates 31, a cylinder portion 32, a piston 33, and brake hydraulic oil. A hole 34 and a cylinder chamber 35 are provided. The disc 30 is attached to a mounting portion provided on the outer peripheral portion of the wheel hub 18 so as to be slidable in the direction of the rotation axis H at a predetermined interval. The plate 31 is attached to a mounting portion provided on the inner peripheral portion of the end portion 5b of the axle housing so as to be slidable in the direction of the rotation axis H at a predetermined interval. 31 are arranged alternately. The cylinder portion 32 is formed in a cylindrical shape having a step at the inner portion of the end portion 5b of the axle housing 5 so that the center portion of the axle housing 5 has a large diameter. The piston 33 has a cylindrical shape with a step so that the center of the axle housing 5 has a large diameter, and is fitted into the cylinder portion 32. A cylinder chamber 35 is formed between the step portion of the cylinder portion 32 and the step portion of the piston 33. The brake hydraulic oil hole 34 is formed in the cylinder portion 32 so as to communicate with the cylinder chamber 35.

  In the wet multi-plate brake 3 configured as described above, when the driver depresses a brake pedal (not shown) while the vehicle is running, the hydraulic pressure is supplied to the cylinder chamber 35 via the brake hydraulic oil hole 34. The As a result, the piston 33 moves to the right side in FIG. As a result of this pressure contact, frictional heat is generated at the pressure contact portion between the disk 30 and the plate 31, and the rotation of the wheel is restricted from the disk 30 via the wheel hub 18 to brake the vehicle. When the driver releases the brake pedal, the hydraulic pressure supplied to the piston 33 is released. Then, the piston 33 is returned to its original position by a spring (not shown), and the braking of the vehicle is released.

  A predetermined amount of lubricating oil is stored in the axle housing 5. The lubricating oil is surrounded by the axle housing 5, the wheel hub 18, and the cap 19, and is sealed at an appropriate position between these members, thereby preventing leakage to the outside. In the present embodiment, lubricating oil is stored up to a substantially central level in the vertical direction of the axle housing 5 (not shown), and the differential 1, the axle shaft 2, the wet multi-plate brake 3, and the final deceleration are performed by this lubricating oil. The device 4 is oil lubricated. The differential 1, each wet multi-plate brake 3, and each final reduction gear 4 are configured to be oil-lubricated in a communicating state through a gap between the axle housing 5 and the axle shaft 2.

  The lubricating oil cooling mechanism 6 is for circulating and cooling the lubricating oil stored in the axle housing 5 to the outside of the axle housing 5, and includes a lubricating oil outlet port 60, pipes 61 to 64, and lubricating oil introduction. A port 65, a suction filter 66, an oil pump 67, an oil cooler 68, and a flow divider 69 are provided.

  The lubricating oil lead-out port 60 is provided below the central portion 5 a of the axle housing 5, and one end of a pipeline 61 is connected to the lubricating oil lead-out port 60. The other end of the conduit 61 is connected to the suction port of the oil pump 67. The suction filter 66 is for filtering foreign matter contained in the lubricating oil on the suction side of the oil pump 67, and is provided in the middle of the pipeline 61. As the oil pump 67, for example, an external gear pump (double pump) is used. One end of a pipeline 62 is connected to the discharge port of the oil pump 67. An oil cooler 68 is provided in the middle of the pipeline 62. The other end of the pipe line 62 is connected to the inflow port of the flow divider 69. The flow divider 69 is for equally dividing the lubricating oil flowing in from the inflow port into two hands and discharging it to the two outflow ports. One end of the pipes 63 and 64 is connected to the outflow port of the flow divider 69. Lubricating oil introduction ports 65 are respectively provided below both end portions 5 b of the axle housing 5. The other ends of the pipes 63 and 64 are connected to each lubricating oil introduction port 65. Although the oil cooler 68 is provided in the present embodiment, the oil cooler 68 may not be provided when the lubricating oil is sufficiently cooled by heat radiation while passing through the pipes 61 to 64.

  The oil pump 67 is operated by the hydraulic pressure for the wet multi-plate brake 3. Specifically, as shown in FIG. 1, the oil pump 67 is configured so that the hydraulic pressure supplied from the pump 10 for the brake device that is always driven is supplied to the charging valve 11, the pipe line 12, and the hydraulic motor 13. It is actuated by being transmitted as a rotational force via. The charging valve 11 is for controlling the flow rate and pressure sent from the pump 10 to an accumulator (not shown) for the brake device. The charging valve 11 starts supplying hydraulic pressure to the accumulator when the pressure of the accumulator is equal to or lower than a predetermined value, and when the pressure of the accumulator is equal to or higher than a predetermined value, the hydraulic pressure to the accumulator is charged. And the hydraulic pressure is supplied to the pipeline 12 connected to a drain port (not shown). The hydraulic fluid is supplied to the accumulator side and the pipeline 12 side. Has the function of switching. The hydraulic pressure is supplied to the pipe line 12 almost always except for a part of time during which the hydraulic pressure is supplied to the accumulator. The pipe line 12 is connected to the suction port of the hydraulic motor 13. The output shaft of the hydraulic motor 13 is connected to the input shaft of the oil pump 67. The discharge port of the hydraulic motor 13 is connected to the tank via the cooler 14. A relief valve 15 for circuit protection is connected to the pipe line 12.

  Next, the operation of the axle device A will be described.

  When the brake device pump 10 is always driven, the hydraulic pressure is almost always supplied to the pipe line 12 through the charging valve 11. In the hydraulic motor 13, the output shaft is rotated by the hydraulic pressure supplied via the suction port, and this rotation is transmitted to the oil pump 67 to operate the oil pump 67.

  When the oil pump 67 is actuated, the lubricating oil around the differential 1 in the axle housing 5 is sucked into the oil pump 67 through the lubricating oil outlet port 60 provided in the central portion 5a of the axle housing and the pipe line 61, and the pipe It is sent out to the path 62. The lubricating oil is then forced to cool by passing through the oil cooler 68. The forcibly cooled lubricating oil flows into the flow divider 69, where it is evenly divided and then sent out to the pipes 63 and 64, respectively. The lubricating oil is supplied into the axle housing 5 through the lubricating oil introduction ports 65 and 65 provided at both ends 5b and 5b of the axle housing.

  In the present embodiment, the drive source of the oil pump 67 for forcibly sending the lubricating oil in the axle housing 5 to the external pipeline is the operation of the wet multi-plate brake 3 as a service brake installed in the vehicle. Since it is a part of hydraulic pressure (excess hydraulic pressure), the oil pump 67 can be operated stably.

  In the axle device A of the present embodiment, the lubricating oil cooled outside the axle housing 5 by the operation of the oil pump 67 passes through the lubricating oil introduction ports 65 and 65 provided at both ends 5b and 5b of the axle housing 5. Through the axle housing 5. For this reason, the lubricating oil around the wet multi-plate brake 3 built in both end portions 5b, 5b of the axle housing 5 is efficiently cooled. Therefore, even if the frictional heat generated at the pressure contact portion between the disk 30 and the plate 31 of the wet multi-plate brake 3 due to heavy braking is excessive, the temperature of the lubricating oil around the wet multi-plate brake 3 is extremely high. Ascending is avoided. As a result, problems such as seizure of the pressure contact portion of the wet multi-plate brake 3 are appropriately prevented, and the durability of the wet multi-plate brake 3 is improved.

  In the axle device A of the present embodiment, since the hydraulic pressure for the service brake already installed in the vehicle is used as the operating source of the oil pump 67 for sending the lubricating oil, a dedicated operating source is provided separately. There is no need. Further, when the working hydraulic pressure for the service brake is used as the working source of the oil pump 67, the arrangement location of the oil pump 67 is not restricted and the degree of design freedom can be increased. Therefore, in the axle device A according to the present embodiment, the structure can be simplified as compared with the case where an oil pump interlocking with a differential is provided in the housing as in the prior art.

  In the axle device A of the present embodiment, the hydraulic pressure for operating the oil pump 67 is supplied via the charging valve 11 that controls the pressure accumulation of the accumulator for the wet multi-plate brake 3. According to such a configuration, by using the charging valve 11 provided in the vehicle as the hydraulic oil circuit of the wet multi-plate brake 3 which is a service brake, when the hydraulic pressure is not supplied to the accumulator The surplus hydraulic oil pressure can be effectively supplied as the oil pump 67 operating source. Accordingly, the supply of the hydraulic pressure for operating the oil pump 67 is simple and efficient.

  In the present embodiment, a flow divider 69 that evenly distributes the lubricating oil sent from the oil pump 67 is provided between the lubricating oil introduction ports 65 and 65 and the oil pump 67. For this reason, the supply amount of the lubricating oil supplied into the axle housing 5 through the lubricating oil introduction ports 65 and 65 is the same or substantially the same. Therefore, the lubricating oil around the left and right wet multi-plate brakes 3 is cooled in a balanced manner, which is suitable for improving the durability of the wet multi-plate brake 3.

  FIG. 3 shows another example of an axle device according to the present invention. In the figure, the same or similar elements as those in the above embodiment are denoted by the same reference numerals as those in the above embodiment, and the description thereof is omitted.

  In the axle device A1 shown in FIG. 3, operating hydraulic pressure supply control means 7 for controlling the supply of the operating hydraulic pressure supplied to the oil pump 67 via the charging valve 11 is additionally provided. However, it differs from the axle apparatus A in the said embodiment.

  The hydraulic pressure supply control means 7 includes a temperature adjustment valve 70 and a switch valve 71. The temperature control valve 70 is provided so as to introduce lubricating oil around the wet multi-plate brake 3 built in the end portion 5 b of the axle housing 5. The temperature control valve 70 is configured to be adjustable so that the degree of opening thereof increases as the temperature of the introduced lubricating oil increases. The switch valve 71 has a function of detecting the pilot pressure from the temperature control valve 70 and supplying the operating oil pressure from the charging valve 11 to the tank side or the hydraulic motor 13 side. In the switch valve 71, when the temperature of the lubricating oil around the wet multi-plate brake 3 is low and the pilot pressure from the temperature control valve 70 is small, the relief pressure to the hydraulic motor 13 side is reduced, and the wet multi-plate brake When the temperature of the lubricating oil around No. 3 is high and the pilot pressure from the temperature control valve 70 is high, the relief pressure to the hydraulic motor 13 side can be increased.

  In the axle device A1 in the present embodiment, the oil pump 67 rotates at a low speed when the temperature of the lubricating oil around the wet multi-plate brake 3 is low, and the temperature of the lubricating oil around the wet multi-plate brake 3 is high. There is a high rotation. That is, according to the present embodiment, the rotation of the oil pump 67 can be controlled in accordance with the temperature of the lubricating oil around the wet multi-plate brake 3, and as the temperature of the lubricating oil increases, the lubricating oil introduction port 65, The supply amount of the cooled lubricating oil supplied into the axle housing 5 through 65 can be increased. Therefore, it is more suitable for efficiently cooling the lubricating oil around the wet multi-plate brake 3.

  In this embodiment, the operating hydraulic pressure supply control means 7 is configured to control the switch valve 71 by the pilot pressure from the temperature control valve 70. Instead of this, for example, an electromagnetic signal is generated by an electric signal from a temperature sensor. It is good also as a structure which controls a valve | bulb.

  Although specific embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

It is a schematic structure figure showing an example of an axle device concerning the present invention. It is a partially cutaway sectional view of the principal part of the axle device of FIG. It is a schematic block diagram which shows the other example of the axle apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Differential 2 Axle shaft 3 Wet multi-plate brake 4 Final reduction gear 5 Axle housing 5b End (Axle housing)
11 Charging valve 60 Lubricating oil outlet port 61 to 64 Pipe 65 Lubricating oil introduction port 67 Oil pump 69 Flow divider A, A1 Axle device

Claims (5)

There is provided an axle housing that houses a differential and an axle shaft extending from the differential to the left and right, and wet multi-plate brakes are built in both ends of the axle housing, respectively, and the differential and the wet are installed in the axle housing. A multi-plate brake is an axle device that is oil-lubricated in a communication state.
The axle housing is provided with a lubricating oil outlet port near the differential and a lubricating oil inlet port at both ends,
An oil pump is linked to the pipe connected to the lubricating oil lead-out port and the pipe connected to the lubricating oil introduction port, and this oil pump has a hydraulic pressure for the wet multi-plate brake. Actuated by a hydraulic motor rotating by supply,
By the operation of the oil pump, wherein the lubricating oil derived from the lubricating oil outlet port is configured to be introduced into the forced within the axle housing through the lubricating oil introducing port, axle device .   The axle device according to claim 1, further comprising a final reduction gear disposed at both ends of the axle housing.   The axle device according to claim 1 or 2, wherein the hydraulic pressure for operating the oil pump is supplied through a charging valve that controls pressure accumulation in the accumulator for the wet multi-plate brake.   The axle device according to any one of claims 1 to 3, wherein a flow divider is provided between the lubricating oil introduction port and the oil pump to evenly distribute the lubricating oil sent from the oil pump.   The supply of the hydraulic pressure for operating the oil pump is performed via hydraulic pressure supply control means for controlling the supply amount according to the temperature of the lubricating oil around the wet multi-plate brake. Axle device according to the above.

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