JP2004150597A - Variable capacity fluid coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable capacity fluid coupling having a torque capacity greatly controllable to be large or small depending on operating conditions. <P>SOLUTION: A pump impeller 3 is divided into an inside pump half 3A and an outside pump half 3B encircling the inside pump half 3A and relatively rotatable therewith. The inside pump half 3A is connected to an input shaft 1 and a centrifugal clutch 20 is provided between both pump halves 3A, 3B for connecting both of them. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fluid coupling in which a pump impeller connected to an input shaft and a turbine impeller connected to an output shaft are opposed to each other, and a circulation circuit of working oil is formed therebetween. The present invention relates to a variable displacement fluid coupling capable of controlling the size of a fluid coupling.
[0002]
[Prior art]
Conventionally, in the case of a fluid coupling, a baffle plate protruding into a circulation circuit is provided on one of a pump impeller and a turbine impeller in order to reduce a torque capacity and suppress a drag torque when an engine is idling. It is already known, as disclosed in document 1.
[0003]
[Patent Document 1]
JP, 2002-21970, A
[Problems to be solved by the invention]
However, the fluid coupling with the baffle plate as described above also reduces the torque capacity in the running state, so that it is necessary to sacrifice the transmission efficiency to some extent.
[0005]
SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and has as its object to provide a variable displacement type fluid coupling capable of controlling the torque capacity in accordance with operating conditions.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a pump impeller connected to an input shaft and a turbine impeller connected to an output shaft facing each other, and forming a hydraulic oil circulation circuit therebetween. In this fluid coupling, the pump impeller is divided into an inner pump half and an outer pump half that surrounds the inner pump half and can rotate relative to the inner pump half. A first feature is that one of the bodies is connected to the input shaft, and a clutch means is provided between both pump halves for connecting and disconnecting them.
[0007]
The input shaft, output shaft, and clutch means correspond to a crankshaft 1, a transmission main shaft 2, and a centrifugal clutch 20 in an embodiment of the present invention, which will be described later.
[0008]
According to the first feature, when the clutch means is brought into the disengaged state, one of the inner and outer pump halves is stopped to reduce the pump function of the pump impeller by half, thereby effectively controlling the torque capacity to be small. When the clutch means is connected, the inner and outer pump halves can be connected to perform the full pumping function of the pump impeller, and the torque capacity can be controlled as usual to a large extent. .
[0009]
According to the present invention, in addition to the first feature, the clutch means is provided between a turbine core ring of the turbine impeller and a pump coring inner and an outer of the inner and outer pump halves. The second feature is that the unit is arranged in the space.
[0010]
According to the second feature, by utilizing the space between the coring rings for the installation of the clutch means, it is possible to control the torque capacity without obstructing the flow of the working oil in the circulation circuit and to control the fluid capacity. This can contribute to reducing the size and weight of the joint.
[0011]
Further, according to the present invention, in addition to the first feature, one end of a transmission case accommodating the pump impeller and the turbine impeller and serving as an external circuit communicating with the circulation circuit is connected to the input shaft. A third feature is that one of the inner pump half and the outer pump half is connected to the other end, and the clutch means is disposed in the external circuit.
[0012]
According to the third feature, the torque capacity can be controlled without obstructing the flow of the working oil in the circulation circuit by using the external circuit for the installation of the clutch means. Because it can be freely expanded without affecting the circulating circuit, it is easy to install even large clutch means.
[0013]
According to a fourth aspect of the present invention, in addition to any one of the first to third aspects, the clutch means is constituted by a centrifugal clutch which is in a clutch-on state in response to an increase in the rotation speed of the input shaft. Features.
[0014]
According to the fourth feature, it is possible to automatically control the torque capacity to be small when the engine is idling and to be large when the engine is running. Therefore, the drag torque is suppressed to a small value at the time of idling, and the torque capacity is controlled to a high value at the time of running at a high load. Transmission efficiency can be ensured.
[0015]
According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, a baffle plate projecting into the circulation circuit is provided on one of the pump impeller and the turbine impeller. I do.
[0016]
According to the fifth feature, when the clutch means is in the disengaged state, the reduction of the torque capacity can be effectively controlled by the synergistic action of the baffle plate and half of the pump function.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below based on preferred embodiments of the present invention shown in the accompanying drawings.
[0018]
1 is a longitudinal sectional view of a variable displacement fluid coupling for a vehicle according to a first embodiment of the present invention, FIG. 2 is a sectional view taken along line 2-2 of FIG. 1, and FIG. 4 is an operation explanatory view corresponding to FIG. 3, FIG. 5 is a longitudinal sectional view of a variable displacement fluid coupling according to a second embodiment of the present invention, and FIG. FIG. 7 is a comparison diagram of the number-torque capacity coefficient characteristic, FIG. 7 is a comparison diagram of the speed ratio-torque capacity coefficient characteristic of the fluid coupling of the present invention and the conventional one at an engine speed of 650 rpm, and FIG. FIG. 9 is a comparison diagram of speed ratio-torque capacity coefficient characteristics at the time of an engine rotation speed of 1000 rpm between a conventional motor and a conventional motor.
[0019]
The description starts with the description of the first embodiment of the present invention shown in FIGS.
[0020]
First, in FIG. 1, a crankshaft 1 of an automobile engine and a transmission main shaft 2 of a multi-stage transmission are coaxially arranged, and these are connected via a fluid coupling F.
[0021]
The fluid coupling F includes a pump impeller 3 and a turbine impeller 4 which opposes the pump impeller and defines a circulation circuit 5 for operating oil therebetween. It is connected to the crankshaft 1 via a drive plate 7 also serving as a ring gear. A small-diameter hub 8ha is formed on the side wall of the transmission case 8 on the drive plate 7 side, and a large-diameter hub 8hb is formed on the opposite side wall. The tip of the transmission main shaft 2 is provided on the inner periphery of the small-diameter hub 8ha. It is rotatably supported via a bush 9.
[0022]
A turbine hub 4h is spline-coupled to the outer periphery of the transmission main shaft 2, and the large-diameter hub 8hb is supported on the outer periphery of the turbine hub 4h via a ball bearing 10 so as to be relatively rotatable. At this time, the inner race of the ball bearing 10 is fixed to the outer periphery of the turbine hub 4h by the annular shoulder 11 and the retaining ring 12, and the outer race is fixed to the inner periphery of the large-diameter hub 8hb and the end wall 13 thereof. It is fixed with the retaining ring 14. In this way, the axial movement of the turbine impeller 4 and the transmission case 8 is restricted via the ball bearing 10.
[0023]
The turbine impeller 4 includes a turbine shell 4s welded to the outer periphery of a turbine hub 4h, a large number of annularly arranged turbine blades 4b, 4b,... Fixed to the inner surface of the turbine shell 4s. 4b ... and a turbine coring 4c for connecting the tips of the turbine cores 4c.
[0024]
On the other hand, the pump impeller 3 is divided into an inner pump half 3 </ b> A and an outer pump half 3 </ b> B surrounding the inner pump half 3 </ b> A, and the inner pump half 3 </ b> A together with the annular baffle plate 15 protruding into the circulation circuit 5. A pump shell inner 3sa welded to the outer periphery of the large-diameter hub 8hb, and a number of annularly arranged pumps fixed to the inner surface of the pump shell inner 3sa and opposed to the inner peripheral half of the turbine blades 4b, 4b. , And a pump coring inner 3ca that faces the inner peripheral half of the turbine core ring 4c while connecting the tips of the pump blade inners 3ba, 3ba. Further, the outer pump half 3B is welded to the collar 16 rotatably fitted to the outer periphery of the large-diameter hub 8hb and extends radially outward while covering the back surface of the pump shell inner 3sa; A plurality of annularly arranged pump blade outers 3bb, 3bb, which are fixed to the inner surface of the pump shell outer 3sb and face the outer peripheral half of the turbine blades 4b, 4b,. The outer peripheral half of the turbine core ring 4c and the pump coring outer 3cb facing each other are connected to each other while connecting the tips. The axial movement of the collar 16 is restricted by the pump shell inner 3sa and the flange 17 on the large-diameter hub 8hb.
[0025]
A centrifugal clutch 20 capable of connecting the inner pump half 3A and the outer pump half 3B is provided in the inter-coring space 18 defined by the turbine coring 4c and the pump coring inner and outer 3ca, 3cb. Is established.
[0026]
The centrifugal clutch 20 will be described with reference to FIGS.
[0027]
The centrifugal clutch 20 is formed integrally with the pump coring outer 3cb and has a clutch drum 21 having a friction lining 21a adhered to the inner peripheral surface thereof, and a plurality of clutch weights 23 having an annular arrangement capable of moving forward and backward with respect to the friction lining 21a. , 23... Each clutch weight 23 includes a weight portion 23a facing the friction lining 21a, and a support member 23b having a U-shaped cross section for supporting the weight portion 23a, and a guide opening on a radial side wall of the support member 23b. A guide member 25 formed integrally with the pump coring inner 3ca passes through the hole 24. As a result, the rotation of the clutch weight 23 by the guide member 25 is allowed, and the advance / retreat of the friction lining 21a, that is, the engagement / separation is allowed. A return spring 26 for urging the clutch weight 23 in a direction away from the friction lining 21a is contracted between the guide member 25 and the support member 23b.
[0028]
Referring again to FIG. 1, the inside of the transmission case 8 is an external circuit 6 that communicates with the outer peripheral flow path of the circulation circuit 5. The external circuit 6 can directly connect the turbine impeller 4 and the transmission case 8. A lock-up clutch L is provided. The lock-up clutch L includes a clutch piston 28 slidably supported on an outer peripheral surface of a turbine hub 4h via a seal member 27. A flat outer surface of the transmission case 8 An annular friction lining 28a facing the inner wall is bonded. Thus, the clutch piston 28 can slide on the turbine hub 4h between a connection position where the friction lining 28a is pressed against the inner wall of the transmission case 8 and a non-connection position separated from the inner wall. .
[0029]
The clutch piston 28 is connected via a torque damper 31 to a plurality of transmission claws 30 projecting from the back of the turbine impeller 4.
[0030]
The external circuit 6 is partitioned by the clutch piston 28 into a first chamber 6a on the side of the friction lining 28a and a second chamber 6b on the side opposite to the friction lining 28a. It is continuous on the side. The transmission main shaft 2 is provided with a first oil passage 34 communicating with the inner peripheral side of the first chamber 6a. A large-diameter hub 8hb of the transmission case 8 is integrally provided with a cylindrical oil pump drive shaft 33 which is arranged so as to surround the transmission main shaft 2 and drives an oil pump 37. A second oil passage 35 is defined between the transmission main shaft 2 and the inner peripheral flow path of the circulation circuit 5 via the ball bearing 10. The first oil passage 34 and the second oil passage 35 are alternately connected to a discharge side of an oil pump 37 and an oil reservoir 38 by a switching valve 39.
[0031]
Next, the operation of the first embodiment will be described.
[0032]
When the engine is started, the rotational torque of the crankshaft 1 is transmitted from the drive plate 7 to the transmission case 8 and the inner pump half 3A. At this time, if the engine is idling, in the centrifugal clutch 20, the clutch weight 23 is separated from the inner peripheral surface of the clutch drum 21, that is, the friction lining 21a by the set load of the return spring 26 as shown in FIG. As a result, the outer pump half 3B is brought into a rest state because the clutch is off.
[0033]
On the other hand, when the engine is idling or operating at a low speed, the switching valve 39 connects the first oil passage 34 to the discharge side of the oil pump 37 and connects the second oil passage 35 to the oil sump 38 as shown in FIG. The connection is controlled by an electronic control unit (not shown). Therefore, when the oil pump drive shaft 33 connected to the transmission case 8 drives the oil pump 37, the operating oil discharged from the oil pump 37 flows from the switching valve 39 to the first oil passage 34, the first chamber 6 a of the external circuit 6, and the like. After flowing into the circulation circuit 5 through the second chamber 6b and filling the circuit 5, the fluid flows to the second oil passage 35 via the ball bearing 10, and is returned from the switching valve 39 to the oil reservoir 38.
[0034]
Since the hydraulic oil flows from the first chamber 6a to the second chamber 6b in the external circuit 6 as described above, the clutch piston 28 is pulled away from the inner wall of the transmission case 8, so that the lock-up clutch L is not connected. In this state, the relative rotation of the transmission case 8 and the turbine impeller 4 is allowed.
[0035]
When only the inner pump half 3A is rotationally driven from the crankshaft 1 through the drive plate 7 and the transmission case 8, the kinetic energy given to the working oil in the circulation circuit 5 by the rotation is relatively small. The torque transmitted from the working oil to the turbine impeller 4 is also relatively small. That is, the pump impeller 3 is in a state where the original pump function is reduced by half, so that the drag torque can be reduced.
[0036]
Moreover, since the baffle plate 15 protrudes from the inner peripheral flow path of the circulation circuit 5 and gives resistance to the circulation of the working oil, a synergistic effect with halving the pump function reduces the amount of the baffle plate 15 to the circulation circuit 5. The drag torque can be more effectively reduced by the protrusion amount.
[0037]
When the engine shifts from idling to a predetermined low-speed operation range, that is, when the rotation speed of the inner pump half 3A reaches a predetermined value, the centrifugal force of the clutch weight 23 that rotates together with the inner pump half 3A causes the set load of the return spring 26 to increase. 4, the clutch weight 23 moves radially outward and comes into pressure contact with the friction lining 21a of the clutch drum 21 as shown in FIG. Therefore, the centrifugal clutch 20 is in a clutch-on state and connects the inner pump half 3A and the outer pump half 3B, so that both pump halves 3A and 3B, that is, the entire pump impeller 3 together with the transmission case 8 are connected. By rotating, the original full pump function is exerted, and a large kinetic energy is applied to the working oil of the circulation circuit 5, and the working oil transmits a large torque to the turbine impeller 4. As a result, as apparent from FIGS. 6 to 8, the torque capacity is the smallest in the idling region of the engine, and rapidly increases when the engine exceeds a predetermined rotation speed.
[0038]
Thus, the fluid coupling F is desirably controlled to minimize the drag capacity during engine idling and to reduce drag torque during normal running, and to maximize torque capacity during normal running to ensure high transmission efficiency under high loads. Can have properties.
[0039]
In addition, since the centrifugal clutch 20 is installed using the space 18 between the coring formed by the pump coring inner and outer 3ca, 3cb and the turbine coring 4c, the centrifugal clutch 20 is The flow of the working oil is not hindered, and the transmission efficiency can be improved and the fluid coupling F can be reduced in size and weight.
[0040]
When the speed ratio between the pump impeller 3 and the turbine impeller 4 approaches 1, the second oil passage 35 is connected to the discharge side of the oil pump 37 by switching the switching valve 39 by an electronic control unit (not shown). At the same time, the first oil passage 34 is connected to the oil reservoir 38. As a result, the operating oil discharged from the oil pump 37 passes through the second oil passage 35 from the switching valve 39, flows into the circulation circuit 5 through the ball bearing 10, and fills the circuit 5, contrary to the previous operation. Thereafter, the external circuit 6 is also filled. At this time, the first chamber 6a of the external circuit 6 is opened to the oil reservoir 38 via the first oil passage 34 and the switching valve 39, so that in the external circuit 6, the second chamber 6b is in the first chamber 6a. As the pressure becomes higher, the clutch piston 28 is pressed against the inner wall of the transmission case 8 by the pressure difference, and the friction lining 28a is pressed against the inner wall of the transmission case 8, and the lock-up clutch L is brought into the connected state.
[0041]
According to the connection of the lock-up clutch L, the transmission case and the turbine impeller 4 are directly connected to each other, so that the rotational torque of the crankshaft 1 can be efficiently transmitted to the transmission main shaft 2, that is, high transmission efficiency is achieved. In this state, fuel efficiency can be reduced.
[0042]
Next, a second embodiment of the present invention shown in FIG. 5 will be described.
[0043]
In the second embodiment, the centrifugal clutch 20 is provided in the external circuit 6. That is, a portion of the outer pump shell 3sb that covers the back surface of the inner pump shell 3sa forms a bottomed cylindrical clutch drum 21. A collar 16 fixed to the inner peripheral end of the clutch drum 21 forms a large transmission case 8. It is supported on the outer periphery of the diameter hub 8hb so as to be relatively rotatable. The axial movement of the collar 16 is restricted by the flange 17 and the retaining ring 41 on the large-diameter hub 8hb. A guide member 25 that penetrates the guide hole 24 of the clutch weight 23 is fixed to the outer surface of the inner pump shell 3sa.
[0044]
Since other configurations are the same as those of the previous embodiment, the same reference numerals in FIG. 5 denote parts corresponding to those of the previous embodiment, and a description thereof will be omitted.
[0045]
According to the second embodiment, by expanding the external circuit 6, even the large-sized centrifugal clutch 20 can be easily installed, and the circulation circuit 5 is not affected at all.
[0046]
The present invention is not limited to the above embodiment, and various design changes can be made without departing from the gist of the present invention. For example, in the pump impeller 3, the outer pump 3B side may be connected to the transmission case 8, and the inner pump half 3A may be driven from the outer pump half 3B by connecting the centrifugal clutch 20.
[0047]
【The invention's effect】
As described above, according to the first aspect of the present invention, the pump impeller connected to the input shaft and the turbine impeller connected to the output shaft face each other, and a hydraulic oil circulation circuit is provided therebetween. In the formed fluid coupling, the pump impeller is divided into an inner pump half and an outer pump half surrounding the inner pump half and capable of rotating relative to the inner pump half. One of the outer pump halves is connected to the input shaft, and a clutch means is provided between the two pump halves for connecting and disconnecting them. , The torque capacity can be largely controlled.
[0048]
According to a second aspect of the present invention, in addition to the first aspect, the clutch means is provided by a turbine coring of the turbine impeller and a pump coring inner and an outer of the inner and outer pump halves. Since it is located in the space between the coring lines that is defined, the space between the coring lines is used to install the clutch means, so that the flow of hydraulic oil in the circulation circuit is not obstructed and the torque capacity can be controlled. And contribute to the miniaturization and weight reduction of the fluid coupling.
[0049]
According to a third aspect of the present invention, in addition to the first aspect, one end of a transmission case accommodating the pump impeller and the turbine impeller and forming an internal circuit as an external circuit communicating with the circulation circuit. Is connected to the input shaft, one of the inner pump half and the outer pump half is connected to the other end, and the clutch means is provided in the external circuit, so that the external circuit is used for installing the clutch means. By doing so, it is possible to control the torque capacity without obstructing the flow of hydraulic oil in the circulation circuit, and the external circuit can be expanded freely without affecting the circulation circuit. It is easy to install even with the clutch means.
[0050]
According to a fourth aspect of the present invention, in addition to any one of the first to third aspects, the clutch means is a centrifugal clutch which is in a clutch-on state in response to an increase in the rotation speed of the input shaft. With this configuration, it is possible to automatically control the torque capacity to be small when the engine is idling and to be large when the engine is running. Therefore, the drag torque is suppressed to a small value when the engine is idling, and high transmission efficiency at high load is ensured during the running. be able to.
[0051]
According to a fifth aspect of the present invention, in addition to any one of the first to fourth aspects, a baffle plate protruding into the circulation circuit is provided on one of the pump impeller and the turbine impeller. Therefore, when the clutch means is disconnected, the reduction of the torque capacity can be effectively controlled by the synergistic action of the baffle plate and the stop of one of the inner and outer pump halves.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a variable displacement fluid coupling for an automobile according to a first embodiment of the present invention. FIG. 2 is a sectional view taken along line 2-2 of FIG. 1. FIG. FIG. 4 is an operation explanatory view corresponding to FIG. 3. FIG. 5 is a longitudinal sectional view of a variable displacement fluid coupling according to a second embodiment of the present invention. FIG. 6 is an engine of a fluid coupling of the present invention and a conventional one. FIG. 7 is a comparison diagram of a speed ratio-torque capacity coefficient characteristic between the fluid coupling of the present invention and a conventional one at an engine speed of 650 rpm. Speed ratio-torque capacity coefficient characteristic comparison diagram of the joint and the conventional one at an engine speed of 1000 rpm [Explanation of symbols]
F · · · · · fluid coupling 1 · · · · · input shaft (crankshaft)
2 ····· Output shaft (transmission main shaft)
3 Pump impeller 3A Inner pump half 3B Outer pump half 3ca Pump coring inner 3ca Pump coring outer 4 Turbine Impeller 4c Turbine coring 5 Circulation circuit 6 External circuit 8 Power transmission case 15 Baffle plate 18 Space between coring 20 ··· Clutch means (centrifugal clutch)

Claims (5)

A pump impeller (3) connected to the input shaft (1) and a turbine impeller (4) connected to the output shaft (2) are opposed to each other, and a hydraulic oil circulation circuit (5) is interposed therebetween. In the formed fluid coupling,
The pump impeller (3) is divided into an inner pump half (3A) and an outer pump half (3B) surrounding the inner pump half (3A) and capable of rotating relative to the inner pump half (3A). A clutch means (20) for connecting one of the pump halves (3A) and the outer pump halves (3B) to the input shaft (1) and connecting them between the two pump halves (3A, 3B); A variable displacement fluid coupling characterized by comprising: The variable displacement fluid coupling according to claim 1,
The clutch means (20) is defined by the turbine coring (4c) of the turbine impeller (4) and the pump coring inner and outer (3ca, 3cb) of the inner and outer pump halves (3A, 3B). A variable displacement fluid coupling, which is disposed in a space (18) between coring portions to be formed. The variable displacement fluid coupling according to claim 1,
One end of a transmission case (8) that accommodates the pump impeller (3) and the turbine impeller (4) and forms an external circuit (6) that communicates with the circulation circuit (5) is connected to the input shaft ( 1), one of the inner pump half (3A) and the outer pump half (3B) is connected to the other end, and the clutch means (20) is disposed in the external circuit (6). A variable displacement fluid coupling characterized by the following: The variable displacement fluid coupling according to any one of claims 1 to 3,
A variable displacement type fluid coupling, wherein the clutch means is constituted by a centrifugal clutch (20) which is brought into a clutch-on state in accordance with an increase in the rotation speed of the input shaft (1). The variable displacement fluid coupling according to any one of claims 1 to 4,
A variable displacement fluid coupling characterized in that one of the pump impeller (3) and the turbine impeller (4) is provided with a baffle plate (15) projecting into the circulation circuit (5).

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