JPH08284848A - Oil pump for automatic transmission - Google Patents

Abstract

PURPOSE: To recover some leaked oil from mating faces between a pump housing and a pump cover, thereby making a balance of oil consumption so as to be improvable by setting up an operating oil groove in a circumferential part area where pump discharge pressure becomes high enough, and also a lubricating oil groove in another circumferential area where the pump discharge pressure is low, respectively. CONSTITUTION: A pump driving shaft rotating and driving a pump element is pierced through a pump housing 1, thereby supporting it free of rotation. An operating oil groove 18 is set up in a discharge side area, where pump discharge pressure becomes high, and a lubricating oil groove 19 in a suction port side area, where the pump discharge pressure is low, respectively so as to surround a pump element fitting cavity 1p of the pump housing 1 constituting an oil pump. Then, out of ends nearby with each other, the end of the operating oil groove 18 is overlapped so as to become the radial side being nearer to the pump element fitting cavity 1p, and thereby any leaked oil from the mating faces is recovered. On the other hand, a return circuit R guiding lubricating oil to be fed to an interval between the pump driving shaft and a bush to a suction port 14, is installed there, through which the outflow portion is thus recovered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil pump which is a hydraulic oil supply source for an automatic transmission, and more particularly to a technique for minimizing deterioration of oil balance due to oil leakage from the pump.

[0002]

2. Description of the Related Art As an oil pump for a conventional automatic transmission, for example, Nissan Motor Co., Ltd., June 1989, "Electronic Control Automatic Transmission Maintenance Manual R"
The L4F03A type "and the one shown in FIG. 1 described in Japanese Patent Laid-Open No. 246538/1988, which includes an inner gear 3 and an inner gear in a space defined between the pump housing 1 and the pump cover 2. An outer gear 4 that meshes with the gear 3 is housed therein, and a pump drive shaft 5 that rotationally drives this pump element (inner gear 3 and outer gear 4) is rotatably supported in the pump housing 1 via a bush 6. At the same time, it is connected to an input element (pump impeller) 8 of a torque converter (fluid transmission) 7 between the engine and the automatic transmission so that the engine is always driven.

By the way, the oil pump of the automatic transmission is
In the circumferential region of the discharge side due to the discharge pressure, oil is inevitably leaked through the mating surface between the pump housing and the pump cover. However, in the conventional oil pump, it is common practice to drop the leaked oil as it is into the oil pan of the automatic transmission.

[0004]

Therefore, in the conventional oil pump, it is necessary to cover all the intake oil amount from the oil pan, and the deterioration of the oil balance cannot be avoided.

Japanese Unexamined Patent Publication (Kokai) No. 57-22455 discloses an oil pump having an oil passage formed around a space for accommodating a pump element. In this oil passage, a lock-up command is issued between the oil passages. As it is clear from the fact that a valve or control valve is provided, it is a closed oil passage for transmitting a control signal, not for oil flow (oil circulation), and the function of receiving leaked oil. And, it has no effect on improving oil balance.

On the other hand, as shown in FIG. 1, when lubricating the pump drive shaft rotation support portion (between the pump drive shaft 5 and the bush 6) of the pump housing, generally, a part of the hydraulic oil of the torque converter is pumped. The lubrication is usually performed by flowing out from the inside of the housing to the outside. And, in order to perform this lubrication in a predetermined manner, a certain amount of clearance is required in the pump drive shaft rotation support portion, but on the other hand, this clearance causes interference between the pump element and the wall of the space in which it is housed. In order to avoid this, a relatively large gap must be set between the pump element and the wall of the space. For this reason, in the conventional oil pump, oil leakage becomes more severe, resulting in further decrease in pump efficiency and further deterioration in oil balance.

Further, in the conventional oil pump, the oil used to lubricate the pump drive shaft rotation support portion is returned to the oil pan of the automatic transmission as it is as described above, which also deteriorates the oil balance. I was invited.

According to the present invention, the mating surface between the pump housing and the pump cover is provided with a hydraulic oil groove for supplying hydraulic oil to the fluid transmission and a lubricating oil groove for supplying lubricating oil to the lubrication portion of the automatic transmission. Since it is formed, it is an object of the present invention to improve the oil pump so as to collect the leaked oil in these oil grooves, and to solve the problem relating to the oil balance.

Further, according to the present invention, the oil pump is improved so that the oil used to lubricate the pump drive shaft rotation supporting portion can be collected without being discarded in the oil pan, thereby avoiding further deterioration of the oil balance. The purpose is to

[0010]

For the former purpose, an oil pump for an automatic transmission according to claim 1 accommodates a pump element in a space defined between a pump housing and a pump cover, A pump drive shaft that rotationally drives an element is rotatably supported by penetrating the pump housing and is coupled to an input element of a fluid transmission device between a prime mover and an automatic transmission to supply hydraulic fluid to the fluid transmission device. In the oil pump of the automatic transmission, the operating oil groove and the lubricating oil groove for supplying the lubricating oil to the lubrication portion of the automatic transmission are formed on the mating surface between the pump housing and the pump cover. So that the hydraulic oil groove and the lubricating oil groove are circumferentially adjacent to each other and extend so as to surround the hydraulic oil groove. Arranged in part regions, the lubricating oil grooves,
It is characterized in that it is arranged in the circumferential region where the pump discharge pressure is low.

An oil pump for an automatic transmission according to a second aspect of the present invention is characterized in that end portions of the hydraulic oil groove and the lubricating oil groove, which are close to each other, are overlapped in a radial direction of the pump. is there.

Further, an oil pump for an automatic transmission according to a third aspect of the present invention is characterized in that the end of the hydraulic oil groove is arranged radially inward of the pump with respect to the end of the lubricating oil groove. It is a thing.

In addition, in the oil pump of the automatic transmission according to the fourth aspect, a part of the hydraulic oil of the fluid transmission is caused to flow from the inside to the outside of the pump housing to drive the pump of the pump housing. In the case of the structure for lubricating the shaft rotation supporting portion, a return circuit for guiding the outflow oil to the suction system of the oil pump is provided.

[0014]

In the present invention, an oil pump for an automatic transmission according to a first aspect of the present invention includes a pump drive shaft for accommodating a pump element in a space defined between a pump housing and a pump cover and rotationally driving the pump element. Is rotatably supported through the pump housing and is coupled to an input element of a fluid transmission between a prime mover and an automatic transmission to perform a pumping action, and is formed on a mating surface between the pump housing and the pump cover. A hydraulic oil groove for supplying hydraulic oil to the fluid transmission and a lubricating oil groove for supplying lubricating oil to the lubrication portion of the automatic transmission are circumferentially arranged so as to surround the space accommodating the pump element. The hydraulic oil grooves are extended side by side, the hydraulic oil groove is arranged in a circumferential region where the pump discharge pressure is high, and the lubricating oil groove is arranged in a circumferential region where the pump discharge pressure is low. By disposing the frequency band, to recover the leaked oil from the mating surface of the pump housing and the pump cover.

Further, in the oil pump for an automatic transmission according to a second aspect of the present invention, the end portions of the hydraulic oil groove and the lubricating oil groove, which are close to each other, are overlapped in the radial direction of the pump, and leakage from the mating surface occurs. Collect the oil.

Further, in the oil pump for an automatic transmission according to a third aspect of the present invention, the end portion of the hydraulic oil groove is arranged radially inward of the pump with respect to the end portion of the lubricating oil groove, and from the mating surface. Collect the leaked oil.

In addition, in the oil pump of the automatic transmission according to the present invention, a part of the hydraulic oil of the fluid transmission is caused to flow from the inside to the outside of the pump housing to drive the pump of the pump housing. In the case of the configuration in which the shaft rotation support portion is lubricated, a return circuit for guiding the spilled oil to the suction system of the oil pump is provided, and the lubricating oil flowing out to the oil pan is collected in the suction system.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

The oil pump of the automatic transmission according to the present invention will be described as being arranged in the configuration of FIG. 1 showing the above-mentioned JP-A-63-246538. The structure will be described with reference to FIG. 1. Reference numeral 1 is a pump housing having a pump element fitting recess 1p for accommodating an inner gear 3 and an outer gear 4 which are pump elements, and the pump gear fitting recess 1p is provided with an inner gear. 3 and the outer gear 4 are rotatably fitted, and the gap is filled with a crescent C.
Further, 5 is a torque converter 7 corresponding to a fluid transmission device.
Is connected to the pump impeller 8 which is an input element of the pump, and is a pump drive shaft for rotationally driving the pump element.
Is rotatably supported via a bush 6 fitted to the inner peripheral portion of the. Reference numeral 9 is an oil seal for preventing oil from flowing out for lubricating the pump drive shaft 5 and the bush 6.

Reference numeral 2 denotes a pump cover which is united with the pump housing 1 to form an oil pump, and a stator 10 which forms a torque converter 7 is provided on an inner peripheral portion of the pump cover 2.
And a fixed shaft (stator shaft) 12 that is spline-fitted via a one-way clutch 11 is press-fitted.

At the mating surface between the pump housing 1 and the pump cover 2, a hydraulic oil passage for supplying hydraulic oil to the torque converter 7 and a lubricating oil passage for supplying lubricating oil to the lubrication portion of the automatic transmission 13 are formed. A hydraulic oil groove and a lubricating oil groove are respectively formed. In addition, the oil flowing through the hydraulic oil passage is
Since it is used as hydraulic oil, it has a high pressure and a large flow rate, whereas the oil flowing through the lubricating oil passage is not necessarily a high pressure and has a large flow rate because it is used as a lubricating oil.

Here, the pumping action of the oil pump is shown in FIG.
Explain. Engine driven pump impeller 8
When the inner gear 3 rotates with the outer gear 4 that is in mesh with the inner gear 3 by the pump drive shaft 5 that is always driven by the engine, the oil is sucked into the pump element fitting recess 1p and adjusted to a high pressure. Discharge after pressing.
The oil discharged at this time is supplied to the hydraulic oil passage and the lubricating oil passage, respectively. Up to this point, the configuration is the same as that of the conventional oil pump.

Next, FIG. 2 is a structural view showing the pump housing 1 from the mating surface with the pump cover 2 in the embodiment of the oil pump according to the present invention, and the contact portion with the pump cover 2 is clearly shown by the diagonal lines. The description of the parts having the same reference numerals as the conventional description is omitted.

First, the structure will be described. Reference numeral 14 is an intake port for intake of oil, which communicates with the intake port 15 of the pump element fitting recess 1p. 16 is a discharge port for discharging oil,
It communicates with the discharge port 17 of the pump element fitting recess 1p.
Here, H is a reinforcing member that reinforces the discharge port 16 and enhances the roundness of the pump element fitting recess 1p.

Reference numeral 18 denotes a hydraulic oil groove for supplying hydraulic oil to the torque converter 7. The hydraulic oil groove 18 is arranged in the discharge port 16 (discharge port 17) side region so as to surround the pump element fitting recess 1p. A lubricating oil groove that is formed circumferentially adjacent to the groove 18 and that supplies lubricating oil to the lubricating portion of the automatic transmission 13 is provided on the suction port 14 (suction port 15) side so as to surround the pump element fitting recess 1p. Place in the area.

At this time, the oil leak generated in the discharge port side region where the high-pressure and high-flow rate oil is discharged by the pump action also flows into the hydraulic oil groove 18 which also has the high-pressure and high-flow rate, so that the discharged oil is discharged. Collect leaks and improve oil balance. Further, since the pressure difference between the discharge port side region and the hydraulic oil groove 18 is relatively small, there is also an effect of preventing leakage at the mating surface. Oil leakage in the suction port side region, which is less likely to occur than in the discharge port side region, flows into the lubricating oil groove 19, so that the oil balance is improved similarly to the discharge side.

In addition, even in the case where the working oil groove 18 and the lubricating oil groove 19 are adjacent to each other on the same circumference, the ends of the working oil groove 18 and the lubricating oil groove 19 which are close to each other are connected to the pump element. If the fitting recesses 1p are overlapped in the radial direction, the amount of oil leakage between adjacent ends that do not communicate with each other is recovered, and the oil balance is further improved.

Further, if the end portion of the hydraulic oil groove 18 is arranged radially inside the pump element fitting recess 1p with respect to the end portion of the lubricating oil groove 19, the operation in which the amount of oil leakage is high and the flow rate is large. The ratio of oil flowing into the oil groove 18 is increased, and the oil balance is further improved.

FIG. 3 is a sectional view taken along the line XX of the pump housing 1 shown in FIG. 2, in which the return circuit R is formed in the inner peripheral portion where the bush 8 for rotatably supporting the pump drive shaft 5 is fitted. There is. As shown in FIG. 2, the return circuit R has a suction port 1
It is connected to 4.

In the return circuit R, the oil supplied for lubrication between the pump drive shaft 5 and the bush 6 (pump drive shaft rotation support portion) is not returned to the oil pan, and the suction port 1 is provided.
Since the procedure is returned to 4, the oil used for lubrication is also recovered to further improve the oil balance.

In this case, since the suction port 14 has a negative pressure due to the pump action, the oil flowing into the clearance (gap) between the bush 6 and the pump drive shaft 5 is lubricated even if the clearance is narrow. Sufficient oil can be supplied as the oil, and the oil used for the lubrication is the suction port 1
It also has the effect of making it easier to return to 4.

Further, when the pump element is rotating at a high speed, the negative pressure of the suction port 14 increases, so that cavitation is likely to occur, which causes unpleasant noise due to poor oil tightness and erosion due to cavity collapse. , Return circuit R
The returning oil prevents a sudden drop in negative pressure.

FIG. 4 shows the pump cover 2 shown from the mating surface.
2, the contact portion with the pump housing 1 is shown by diagonal lines as in FIG.

Reference numeral 20 denotes an oil chamber which connects the suction port 14 and the suction port 15 of the pump housing 1 with each other at a mating surface, and the same 2
1 is a discharge port 16 and a discharge port 17 of the pump housing 1.
And 18a and 18b are oil ports communicating with the hydraulic oil groove 18 of the pump housing 1 on the mating surface,
18a is an oil port on the lockup control valve side, and 18b is an oil port on the torque converter 7 side. Similarly, 19a, 1
9b is an oil port communicating with the lubricating oil groove 19 of the pump housing 1 on the mating surface, 19a is an oil port on the lubrication side, and 19b is an oil port on the cooler side.

The oil pump according to the present invention, which is formed by the pump housing 1 and the pump cover 2 described above, has a gap between the mating surfaces of the pump housing 1 and the pump cover 2, and a gap between the pump drive shaft 5 and the bush 6. The oil spilled from is collected in a necessary part.

In this embodiment, the gear type pump has been described, but for example, like the gear type pump, the storage space is limited, and the pump element is configured to change the volume of the pump chamber by rotation. It can also be applied to a variable capacity vane pump or the like.

[0037]

In the oil pump for an automatic transmission according to claim 1 of the present invention, the operating oil groove is arranged in the discharge side area and the lubricating oil groove is arranged in the suction side area.
Oil leaks at the mating surfaces that occur in the high pressure and high flow rate discharge side area can be collected in the same high pressure and high flow rate hydraulic oil groove, and the pressure difference between the discharge side area and the hydraulic oil groove becomes small. Therefore, the effect of preventing leakage also occurs. Further, since the oil leak in the suction port side region where the oil is sucked is collected by the lubricating oil groove, the oil balance can be improved by at least one of the hydraulic oil groove and the lubricating oil groove.

Further, in the oil pump of the automatic transmission according to the second aspect of the present invention, since the end portions of the hydraulic oil groove and the lubricating oil groove which are close to each other are overlapped in the radial direction of the pump, the oil groove and the lubricating oil are lubricated. In the case where the oil groove and the oil groove are adjacent to each other on the same circumference, oil leakage does not occur between adjacent end portions that do not communicate with each other on the mating surface, and the oil balance can be further improved.

Further, in the oil pump of the automatic transmission according to the third aspect of the present invention, since the end portion of the hydraulic oil groove is arranged on the inner side in the radial direction of the pump with respect to the end portion of the lubricating oil groove, Oil leakage in the discharge port side region with a large flow rate can be efficiently supplied to the working oil groove requiring a high pressure and a large flow rate, and the oil balance can be further improved.

In addition, in the oil pump of the automatic transmission according to the present invention, a return circuit for guiding the lubricating oil to the suction system of the oil pump is provided in the structure for lubricating the pump drive shaft and the bush of the pump housing. Therefore, even if the clearance between the pump drive shaft and the bush is made as narrow as possible, it is possible to sufficiently secure the lubricating oil by utilizing the negative pressure in the suction system due to the pump operation, and at the same time to let it flow to the oil pan. The oil balance can be improved because it can be easily returned to the suction system.

Further, since the clearance between the pump drive shaft and the bush is reduced, the interference between the pump element and the pump fitting recess can be reduced, and the pump efficiency can be improved. Further, when the pump element is rotating at a high speed, the amount of return from the return circuit can alleviate a sharp decrease in negative pressure in the suction system, and prevent cavitation, noise, and erosion due to negative pressure.

[Brief description of drawings]

FIG. 1 is a configuration diagram illustrating an oil pump of an automatic transmission that is a conventional technique.

FIG. 2 is a configuration diagram showing a pump housing of an oil pump according to an embodiment from a mating surface side.

FIG. 3 is a sectional view taken along the line XX of the pump housing in the example.

FIG. 4 is a configuration diagram showing a pump cover that constitutes an oil pump according to an embodiment from the mating surface side.

[Explanation of symbols]

 1 pump housing 1p pump element fitting recess 2 pump cover 3 inner gear 4 outer gear 5 pump drive shaft 6 bush 7 torque converter 8 pump impeller 9 oil seal 10 stator 11 one-way clutch 12 fixed shaft (stator shaft) 13 automatic transmission 14 Suction port 15 Suction port 16 Discharge port 17 Discharge port 18 Hydraulic oil groove 18a Oil port on lockup control valve side 18b Oil port on torque converter 6 side 19 Lubricating oil groove 19a Lubricating side oil port 19b Cooler side oil port 20, 21 Oil chamber C Crescent H Reinforcement member R Return circuit

Claims (4)

[Claims] 1. A pump element is housed in a space defined between a pump housing and a pump cover, and a pump drive shaft for rotationally driving the pump element is rotatably supported through the pump housing. Coupled to the input element of the fluid transmission between the prime mover and the automatic transmission,
A hydraulic oil groove for supplying hydraulic oil to the fluid transmission and a lubricating oil groove for supplying lubricating oil to the lubrication portion of the automatic transmission are formed on the mating surface between the pump housing and the pump cover. In the pump, the hydraulic oil groove and the lubricating oil groove are circumferentially adjacent to each other so as to surround a space accommodating the pump element, and the hydraulic oil groove is a circle whose pump discharge pressure is high. An oil pump for an automatic transmission, wherein the lubricating oil groove is arranged in a peripheral region, and the lubricating oil groove is arranged in a peripheral region where the pump discharge pressure is low. 2. The oil pump for an automatic transmission according to claim 1, wherein ends of the hydraulic oil groove and the lubricating oil groove, which are close to each other, overlap in a radial direction of the pump. 3. The oil pump for an automatic transmission according to claim 2, wherein the end portion of the hydraulic oil groove is arranged radially inside the pump with respect to the end portion of the lubricating oil groove. 4. The pump drive shaft rotation of the pump housing according to claim 1, wherein a part of the hydraulic oil of the fluid transmission device flows out from the inside of the pump housing toward the outside. An oil pump for an automatic transmission, comprising a return circuit for guiding the spilled oil to an intake system of the oil pump when the support portion is lubricated.