JPH0710123Y2 - Oil pump for four-wheel drive transfer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to an oil pump for a four-wheel drive transfer device.

[Prior Art] An example of an oil pump used in a conventional four-wheel drive transfer device is shown in FIG.

In FIG. 2, 1 and 2 are casings, and the main shaft 3 has bearings 4, 5 in these casings 1, 2.
It is rotatably supported via. An oil passage 6 is formed inside the main shaft 3 to lubricate each lubrication site.

Reference numeral 7 is a planetary gear mechanism. The planetary gear mechanism 7 is composed of a sun gear 8, a ring gear 9, a carrier 10 rotating on the same axis as these, and a planetary gear 11 supported by the carrier 10. There is. A switching mechanism 12 switches the planetary gear mechanism 7 to low (L) or high (H). The switching mechanism 12 is a hub 13 rotatably supported by the carrier 10.
And a dock gear 14 splined to the carrier 10
And a clutch gear 16 fixed to the casing 15, a coupling sleeve 17 meshing with the clutch gear 16, and a fork 18 for moving the coupling sleeve 17.

Reference numeral 19 denotes a wet multi-plate clutch mechanism for performing 2-4 drive switching and variable torque control.
19 is a drum splined to the main shaft 3.
20 and a plate splined to the inner circumference of the drum 20
21, a hub 23 splined to the drive sprocket 22, and a plate 24 splined to the hub 23,
It is composed of a piston 25 that presses these plates 21 and 24.

A chain 27 is installed between the drive sprocket 22 and the driven sprocket 26.
Is integrally formed with the front drive shaft 28.
The front drive shaft 28 is rotatably supported by the casings 1 and 2 via bearings 29 and 30.

Here, 31 is a pump housing, an oil pump 34 including an inner gear 32 and an outer gear 33 is provided in the pump housing 31, and the oil pump 34 supplies lubricating oil to the oil passage 6.

In addition, an introduction passage 36 for introducing oil for driving the piston 25 is provided in the cover 35 in contact with the pump housing 31.
Is formed, and the introduction passage 36 communicates with the piston liquid chamber 37.

An oil pump 39 and a DC motor 40 for driving the oil pump 39 are attached to the bottom of the casing 2 via a boss portion 38.

Reference numeral 41 is a rotating shaft of the DC motor 40, and 42 is an oil seal attached to the rotating shaft 41. Further, 43 is a pump housing of the oil pump 39, 44 is a pump key, and 45 is an O-ring mounted on the pump housing 43.

Here, in order to release the back pressure of the oil pump 39, the pump housing 43 is drilled to form drain holes 46 and 48, and a plug 47 is press-fitted into the drain hole 46 for caulking.

[Problems to be Solved by the Invention] However, in such a conventional oil pump, two drill holes are provided in the pump housing, and
There was a problem that the plug had to be press-fitted into the drain hole and crimped, which increased the number of processing steps and assembly steps and increased the cost.

The present invention has been made in view of such conventional problems, and an external seal member is provided outside the drain hole, and at least one of the end portion of the housing and the mating member with which the external seal member is in contact. It is an object of the present invention to provide an oil pump in which the draining flow path is formed to reduce the working process and the assembling process and reduce the cost.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an oil pump for a four-wheel drive transfer device, which is driven by a DC motor and has a drain hole for releasing back pressure in a pump housing. An external seal member is disposed outside the drain hole to provide an end portion of a pump housing having a different diameter,
Alternatively, a drain flow path is formed in at least one of both mating members with which the external seal member is in contact.

[Operation] In the present invention, an external seal member is provided outside the drain hole to form a drain flow path by changing the diameter of the oil housing, or the drain flow path is formed on the mating member side with which the external seal member contacts. Since the pump housing is formed, only one drill hole can be drilled in the pump housing, and the plug that press fits into the drain hole is not required and the caulking is also unnecessary. Can be reduced, and the cost can be reduced.

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a view showing an embodiment of the present invention.

First, the configuration will be described. In FIG. 1, 51 is an oil pump, 52 is a DC motor for driving the oil pump 51,
These oil pump 51 and DC motor 52 are attached to the casing of the transfer device via a boss portion.

Reference numeral 53 denotes a pump housing, 54 denotes a cover of the pump housing 53, a pump gear 55 including an inner gear and an outer gear is housed in the pump housing 53, and the pump gear 55 is rotationally driven by a shaft 56 of the DC motor 52.

Reference numeral 57 denotes a discharge port formed in the cover 54, and the hydraulic fluid is supplied from the discharge port 57 by the oil pump 51 to the piston liquid chamber of the piston for operating the wet multi-plate clutch mechanism (not shown).

58 is an oil seal, and the oil seal 58 is a DC motor
It is mounted between the shaft 56 of 52 and the pump housing 53. Further, 59 is a drain hole for releasing the back pressure (see arrow A) of the oil pump 51, and the drain hole 59 is formed in the pump housing 53.

Outside the drain hole 59, an external seal member (O ring) 60 is attached to the pump housing 53, and the O ring 60 prevents oil from leaking to the outside.

Here, the pump housing in which the O-ring 60 is mounted
Assuming that the diameter of 53 is D2 and the diameter of the pump housing 53 without the cover 54 and the O-ring 60 is D1, D2> D1
Each diameter is set so that the drain passage 61 is secured. In addition, the drain channel
The 61 is not limited to the one formed by setting D2> D1 as described above, but may be formed on the mating member 62 side in contact with the O-ring 60.

Next, the operation will be described.

In the present invention, since the O-ring 60 is arranged outside the drain hole 59 and the diameter of the pump housing 53 is set to D2> D1, the drain passage 61 can be secured.

Therefore, there is only one drill hole for drilling in the pump housing 53, and there is no need for a plug press-fitted into the drain hole, and no caulking is required, so the machining and assembly processes can be reduced. The cost can be reduced.

Also, because all the holes are placed inside the O-ring 60,
It is possible to prevent oil leakage.

[Effects of the Invention] As described above, according to the present invention, the pump housing has only one drill hole, and the plug press-fitted into the drain hole is unnecessary, and the caulking is also unnecessary. Therefore, the working process and the assembling process can be reduced, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a half sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional example. In the figure, 51 ... oil pump, 52 ... DC motor (DC motor),
53 …… Pump housing, 54 …… Cover, 55 …… Pump gear, 56 …… Shaft, 57 …… Discharge port, 58 …… Oil seal, 59 …… Drain hole, 60 …… O-ring (external seal member), 61 …… Drain flow path, 62 …… Mating member.

Claims (1)

[Scope of utility model registration request] 1. An oil pump of a four-wheel drive transfer device driven by a direct current motor and having a drain hole for releasing a back pressure in a pump housing, wherein an external seal member is arranged outside the drain hole and has a diameter. Different from the above, the drain pump is formed in at least one of the end of the pump housing and the other member with which the external seal member is in contact, and the oil pump of the four-wheel drive transfer device.