WO2019003297A1 - Fluid pressure clutch - Google Patents

Abstract

The present invention relates to a fluid pressure clutch, comprising: a shaft (7) that is integrally provided with first gear teeth (3) protruding outward in the radial direction; an outer drum (9) that is integrally provided with second gear teeth (5) protruding outward in the radial direction, coaxially surrounds the shaft (7), and is adjacent to the first gear teeth (3) in the axial direction; a drum bottom (19) that is provided with a sleeve (21) and supports the outer drum (9) rotatably to the shaft (7); a clutch plate pair (11) in which plates (13, 15) respectively coupled to the shaft (7) and the outer drum (9) are arranged alternately in the axial direction; a plunger (17) for pressing the clutch plate pair (11) in the axial direction using fluid pressure in a chamber (23) formed between the plunger (17) and the drum bottom (19); and channels (33, 35, 37, 71) including an axial path (33) communicating with a fluid circuit (31) and formed in the shaft (7), the channels connecting the axial path (33) and the chamber (23) while passing through the sleeve (21).

Description

Fluid pressure clutch

The following disclosure relates to an axially compact fluid pressure clutch, and in particular, a structure that operates by supplying fluid pressure from an external fluid circuit axially via a shaft to operate in a compact manner with limited axial dimensions. Fluid pressure clutch.

In recent years, vehicles that combine two or more power sources have appeared on the market to improve energy efficiency. A typical example is a so-called hybrid vehicle. The output of the combustion engine is used not only to drive the axles but also to charge the battery, in which case the motor acts as a generator and generates a part of the output of the combustion engine. Also, in many cases, even when the vehicle decelerates, the motor acts as a generator and regenerates the inertial energy of the vehicle as electric power. That is, torque needs to be exchanged in three directions between two or more power sources and an axle.

Patent Document 1 discloses a related technology.

Japanese Patent Publication 2012-91634

Although the power transmission incorporates a clutch to realize the torque exchange as described above, how to operate the clutch from the outside poses a difficult problem in connection with the layout. That is, since the engine room must be equipped with two or more power sources, the available space is less than conventional vehicles. These power sources are arranged, for example, in the width direction of the vehicle, but the power transmission device has only a small gap between them, and there is no room for mounting. On the other hand, although the actuator for operating the clutch is often placed on the shaft of the clutch shaft and outside the power transmission device, the axial direction coincides with the width direction of the vehicle, so the actuator consumes even such a slight gap Resulting in.

The devices disclosed below were created in view of the above problems.

According to one aspect, a fluid pressure clutch that operates by supplying fluid pressure from an external fluid circuit includes a shaft that integrally includes a first gear tooth that protrudes radially outward; An integrally formed second gear tooth that projects outward, an outer drum coaxially surrounding the shaft and axially adjacent to the first gear tooth, and a sleeve rotatably fitted to the shaft, A drum bottom interposed between the outer drum and the shaft for rotatably supporting the outer drum with respect to the shaft; a first plate coupled to the shaft; and a second plate coupled to the outer drum And the first plate and the second plate are arranged to overlap each other in the axial direction, and a combination of a clutch plate set and the drum bottom encloses a chamber. And a plunger which is fluidly fitted to the drum bottom and axially movable, and is arranged so as to press the clutch plate set axially, and an axial passage which runs axially in the shaft. And a fluid passage in fluid communication with the chamber through the sleeve to create the fluid pressure in the chamber.

FIG. 1 is a schematic view of a power transmission device provided with a fluid pressure clutch according to an embodiment. FIG. 2 is a longitudinal sectional view of a fluid pressure clutch and a fluid circuit. FIG. 3 is an enlarged longitudinal sectional view showing a clutch drum and its related elements in the fluid pressure clutch. FIG. 4 is a longitudinal sectional view mainly showing a fluid circuit and a flow path. FIG. 5A is a partial cross-sectional elevation view mainly showing a sleeve and a circumferential groove. FIG. 5B is a plan view of the shaft mainly showing a portion around the circumferential groove. FIG. 6 is a longitudinal sectional view showing a clutch drum and its related elements according to another example. FIG. 7 is a longitudinal sectional view showing a clutch drum and its related elements according to still another example. FIG. 8A is a longitudinal sectional view showing a clutch drum and its related elements according to another example. FIG. 8B is a longitudinal sectional view mainly showing the sleeve and the oil groove on the inner surface thereof. FIG. 9 is a longitudinal sectional view showing a clutch drum and its related elements according to still another example.

Several exemplary embodiments are described below with reference to the accompanying drawings.

In the following description and the appended claims, unless otherwise stated, the axis means the axis X of the shaft of the clutch and the axial direction means the direction parallel thereto.

Referring to FIG. 1, a so-called hybrid vehicle is provided with a first power source 103, which is an electric motor, for example, and a second power source 105, which is an internal combustion engine, for example. To drive. The generator 107 is connected integrally or through a gear set to the second power source 105, and the generated torque is used for power generation, and the electric power is an electric motor and other electrical components, and the generator 107 itself. Used to drive the

A power transmission device intervenes between the power sources 103 and 105 or the generator 107 and the drive wheel W to transmit torque. The power transmission apparatus includes, for example, a first gear set 109, a differential 111 having a ring gear 113, a second gear set 115, and a clutch 1 interposed between the second gear set 115 and the ring gear 113. , And the whole is accommodated in the casing 101. Both axles are drawn out of the casing 101 from the differential 111 and coupled to the drive wheels W respectively.

In this example, the first power source 103 is always drivingly coupled to the differential 111 via the first gear set 109, but a second gear set in which the second power source 105 and the generator 107 are coupled. The reference numeral 115 is drivingly coupled to the differential 111 only when the clutch 1 is engaged. That is, the traveling mode is selected by the disconnection of the clutch 1.

The clutch 1 is, for example, a fluid pressure clutch operated by fluid pressure such as oil pressure, and a fluid circuit 31 can be used as an actuator for operating the same. The fluid circuit 31 is disposed to be close to the clutch 1, for example, to protrude to the side of the casing 101 or to the outside of the casing 101. The working fluid F is, for example, oil, but may not be dedicated for oil pressure, and a part of the lubricating oil in the power transmission device can be introduced into the fluid circuit 31 and used.

Referring to FIG. 2 in combination with FIG. 1, the fluid circuit 31 supplies pressurized fluid F to the clutch 1, and the pressure causes the clutch 1 to operate. The clutch 1 generally includes a shaft 7 having a first gear tooth 3, an outer drum 9 having a second gear tooth 5, a clutch plate set 11 interposed between the shaft 7 and the outer drum 9, and a fluid It consists of a plunger 17 which is axially driven by pressure to press the clutch plate assembly 11.

The shaft 7 is rotatably supported by the casing 101 by a pair of bearings 51 and 53 such as ball bearings. From the viewpoint of achieving stable rotation, the bearings 51 and 53 should be close to both ends of the shaft 7 respectively. In the example of FIG. 2, the bearing 53 is placed at one end of the shaft 7, and the bearing 51 is placed between the outer drum 9 and the fluid circuit 31. If possible, the bearing 51 may be placed outside the fluid circuit 31 at the other end of the shaft 7. This is advantageous not only in stable rotation but also in shortening the flow path of the fluid F.

First gear teeth 3 project radially outward from the shaft 7 and mesh with the ring gear 113. Although the shaft 7 and the first gear teeth 3 can be integrally formed from the viewpoint of manufacturing convenience and securing of strength, they may be separately manufactured and then integrally connected later. As will be described in detail later, as a flow path of the fluid F, the shaft 7 is provided with an axial passage 33 which runs axially along its axis X. The shaft 7 may further comprise other flow paths independent of the axial path 33, which serve for example to supply lubricating oil to the elements around the shaft 7.

The outer drum 9 is a generally cylindrical element coaxial with the shaft 7 and surrounding it, and a radially outwardly projecting second gear tooth 5 is inscribed in the outer periphery of the outer drum 9. The second gear teeth 5 mesh with the second gear set 115. The second gear teeth 5 may also be separate from the outer drum 9 and may be integrally coupled to the outer drum 9 later. The outer drum 9 can be axially adjacent to the first gear tooth 3.

The clutch 1 further includes a drum bottom 19 between the shaft 7 and the outer drum 9 so as to close one end of the outer drum 9, which is rotatable relative to the shaft 7 and splined to the outer drum 9. I support this. That is, the outer drum 9 rotates relative to the shaft 7 together with the drum bottom 19.

Referring to FIG. 3 in combination with FIGS. 1 and 2, the drum bottom 19 integrally includes a cylindrical sleeve 21 rotatably fitted to the shaft 7. A needle bearing 55 may be interposed between the sleeve 21 and the shaft 7 to facilitate rotation. The lubricating oil flow path of the shaft 7 may extend radially from the axis toward the needle bearing 55, which uses centrifugal force to supply the lubricating oil to the needle bearing 55. A bush may be used instead of the needle bearing 55, or one or more ball bearings 57 may be used as shown in FIGS.

Alternatively, as shown in FIG. 8A, the sleeve 21 may be fitted to the shaft 7 directly without the intervention of a bearing or a bush. An oil groove 59 may be incised on the inner surface of the sleeve 21 or bush as shown in FIG. 8B for the convenience of holding the lubricating oil at the interface. Alternatively, the oil groove may be omitted by utilizing a material excellent in the property of retaining an oil film such as cast iron in the sleeve 21 or the bush.

Referring to FIGS. 3, 6, 7, 8A and 9, in the drum bottom 19, a wall portion substantially orthogonal to the axis X, a short peripheral wall on the outer periphery thereof, and a sleeve 21 on the inner periphery thereof It encloses a relatively shallow annular groove around it. The plunger 17 is fitted in a fluid-tight manner (in a fluid-tight manner if the fluid F is liquid) in the annular groove, and the combination surrounds the chamber 23. In order to ensure fluid tightness, an appropriate seal member such as an O-ring may be interposed between the drum bottom 19 and the plunger 17. Although the details will be described later, the chamber 23 is in fluid communication with the fluid circuit 31 through the flow path, and the pressure of the fluid F causes the plunger 17 to move in the axial direction.

The plunger 17 further extends in the axial direction and faces the clutch plate assembly 11. When the fluid F drives the plunger 17 in the axial direction, the plunger 17 presses the clutch plate assembly 11, whereby the clutch 1 is engaged. . Also, biasing means such as a coil spring may be coupled to the plunger 17 in a direction to return the plunger 17 to its original position so as to disconnect the clutch 1.

The clutch plate set 11 constitutes a cone type, a dog type, or a multiple disc type clutch, but an example of the multiple disc type will be described below. The clutch plate set 11 includes a plurality of first plates 13 coupled to the shaft 7 and a plurality of second plates 15 coupled to the outer drum 9, and the first plate 13 and the second plate 15 have an axis. They are alternately arranged to overlap each other in the direction.

An inner drum 25 may be interposed between the first plate 13 and the shaft 7. As can be understood from the figures, the second gear teeth 5, the clutch plate set 11 and the inner drum 25 can be generally arranged on the same plane orthogonal to the axis X, in other words, they are mutually oversized in the axial direction. It can be wrapped. Furthermore, they can be axially adjacent to the first gear tooth 3. Such an arrangement is advantageous for reducing the axial dimension of the clutch 1.

The connection between the inner drum 25 and the shaft 7 may be press-fit or welding, as shown in FIGS. 3 and 8A. Alternatively, as shown in FIGS. The connection between the plates 13 and 15 and the shaft 7 or the inner drum 25 and the outer drum 9 can be, for example, by splines.

Under the fluid pressure, the plunger 17 presses the clutch plate set 11 and the second power source 105 is drivingly coupled to the differential 111 via the clutch 1 by connecting the two, thereby providing two power sources. Both 103 and 105 drive the drive wheel W. When the clutch 1 is disengaged, only the first power source 103 drives the drive wheel W.

The torque from the second power source 105 is input to the second gear teeth 5 and transmitted to the clutch plate set 11 and the inner drum 25 that are substantially aligned on the same plane, and is transmitted to the first gear teeth 3 adjacent thereto. Reportedly. Such a structure is robust against twisting since the torque is transmitted substantially in the same plane. Neither member needs to consider the strength or rigidity against twist so much, which is advantageous for weight reduction. Needless to say, since the path from the outer drum 9 to the drum bottom 19 and the sleeve 21 does not bear torque, their strength or rigidity requirements are relatively light, which is also advantageous for weight reduction.

Referring to FIGS. 3, 6, 7 and 8A, when the plunger 17 receives fluid pressure, the drum bottom 19 is pushed away from the clutch plate set 11 by the reaction force. In order to resist this, a thrust bearing 61 may be interposed between the drum bottom 19 and the casing 101. The thrust bearing 61 can be arranged, for example, to abut the outer race of the bearing 51 that supports the shaft 7. Since the outer race is made of a particularly hard material, the thrust bearing 61 can be supported without being worn or deformed. Alternatively, a relatively soft material can be applied to the casing 101.

Alternatively, as shown in FIG. 9, a structure may be employed in which the axial force is completed inside the clutch 1. According to this example, there is no thrust bearing, and instead, a ball bearing 63 is interposed axially between the sleeve 21 and the shaft 7 opposite to the clutch plate set 11 with respect to the plunger 17. The pair of ball bearings 63, 57 is sufficient not only to facilitate relative rotation but also to support a reaction force. According to this example, the axial force is not completely leaked to the inside inside the clutch 1, so the degree of freedom with respect to the design outside the clutch drum is improved.

Referring mainly to FIG. 4 in combination with FIGS. 1 and 2, the shaft 7 comprises an extension 79 axially extended beyond the drum bottom 19, the extension 79 being fluid tight in the fluid circuit 31. Get stuck. The axial passage 33 extends to an extension 79, the end of which is suitably closed by a plug 85 or the like. The fluid circuit 31 is stationary and the extension 79 is of course rotatable relative thereto.

The fluid circuit 31 is a device for supplying the pressurized fluid F to the clutch 1 using pressure generated by an external pump or a pump contained in itself. The driving force of the pump may be an electric motor or the driving force may be obtained from the shaft 7. In order to extract the driving force from the shaft 7, the fluid circuit 31 may be provided with a gear-like engagement structure 87 and engaged with the extension 79 or the plug 85.

The fluid circuit 31 is provided with a switching valve 83 to introduce a fixed amount of pressurized fluid F on and off in a switchable manner, and one end of the fluid F passage is closed by a sealing plug like ball 81 It is also good. They open towards the extension 79 and are thus in fluid communication with the axial passage 33. The pressurized fluid F is supplied to the chamber 23 through the axial passage 33 to drive the plunger 17.

The shaft 7 rotates relative to both the sleeve 21 and the fluid circuit 31. Therefore, special care is needed to maintain fluid communication between the fluid F flow paths beyond the mating portions. One example is the structure shown in FIGS. 5A and 5B.

That is, the shaft 7 comprises one or more radial passages 35 penetrating the shaft 7 radially from the axial passage 33 towards the sleeve 21. The sleeve 21 is correspondingly provided with one or more radial passages 37 penetrating the sleeve 21 radially towards the chamber 23. Furthermore, either or both of the outer surface of the shaft 7 and the inner surface of the sleeve 21 are provided with circumferential grooves 71, 73 circumferentially intersecting the radial paths 35, 37. For example, as understood from FIG. 4, even when the radiation passages 35, 37 are not aligned due to the rotation, the radiation passages 35, 37 can be in fluid communication via the circumferential grooves 71, 73.

Referring back to FIG. 4, a similar structure can be utilized with fluid circuit 31. That is, the extension 79 of the shaft 7 comprises one or more radial passages 39 passing through the extension 79 from the axial passage 33 towards the fluid circuit 31 and either or both of the outer surface of the extension 79 and the inner surface of the fluid circuit 31 Is provided with circumferential grooves 75, 77 circumferentially intersecting the radiation path 39, thereby maintaining fluid communication regardless of relative rotation.

As already mentioned, the clutch 1 is axially short, so that the flow path of the fluid F can also be short. When a lubricating oil is used as the fluid F, the lubricating oil contains air bubbles as it is agitated, and therefore has a certain degree of compressibility. If air bubbles increase and compressibility increases, the response from when the valve 83 is actuated and pressurization of the fluid F is started to when the clutch 1 is actuated may be reduced. According to the above-described embodiments, the short flow path reduces the influence of the compressibility, thereby improving the response of the clutch 1.

According to each embodiment, when the clutch 1 is not engaged, not only the outer drum 9, but also the drum bottom 19, the sleeve 21, the plunger 17 and related members are all free from the shaft 7, that is, the vehicle travels Even when doing so, these members can be stopped. Since the first power source 103 does not have to bear these rotations, it can contribute to the improvement of the fuel efficiency of the vehicle.

Although some embodiments have been described, it is possible to make modifications or variations to the embodiments based on the above disclosure.

An axially compact fluid pressure clutch is provided.

Claims (6)

1. A fluid pressure clutch operated by supplying fluid pressure from an external fluid circuit, comprising:
   A shaft integrally provided with a first gear tooth projecting radially outward;
   An outer drum integrally provided with radially outwardly projecting second gear teeth, coaxially surrounding said shaft and axially adjacent said first gear teeth;
   A drum bottom provided with a sleeve rotatably fitted to the shaft, the drum bottom being interposed between the outer drum and the shaft and rotatably supporting the outer drum relative to the shaft;
   A clutch plate set, comprising: a first plate coupled to the shaft; and a second plate coupled to the outer drum, the first plate and the second plate being axially overlapped with each other When,
   A plunger, which is in fluid tight engagement with the drum bottom so as to surround the chamber and which is movable in the axial direction, and which is arranged to press the clutch plate set in the axial direction;
   A flow path including an axial passage running axially in the shaft, through which the fluid circuit is in fluid communication with the chamber through the sleeve to generate the fluid pressure in the chamber;
   Fluid pressure clutch with.
2. The inner drum further includes an inner drum disposed radially inward coaxially with the outer drum and interposed between the shaft and the first plate.
   The fluid pressure clutch according to claim 1, wherein the shaft and the inner drum are fixedly connected by any one or more of welding, spline engagement, and press fitting.
3. The second gear teeth, the clutch plate set, and the inner drum are arranged to axially overlap each other, and the first gear teeth and the inner drum are arranged axially adjacent to each other. The fluid pressure clutch of claim 2, wherein
4. The fluid according to claim 1, wherein said drum bottom comprises an axially-directed thrust bearing or a ball bearing interposed between said sleeve and said shaft on the axially opposite side of said plunger and said clutch plate set. Pressure clutch.
5. The flow path includes a first radial path radially penetrating the shaft from the axial path towards the sleeve and a second radial path radially penetrating the sleeve towards the chamber, the sleeve And at least one of the shaft and the shaft includes circumferential grooves circumferentially intersecting the first radiation path and the second radiation path, whereby the sleeve is rotated relative to the shaft The fluid pressure clutch of claim 1 wherein said circumferential groove maintains fluid communication between said first and second radial passages.
6. The shaft includes an axially extending extension for fluidly rotatable insertion in the fluid circuit, the flow passage radially penetrating the extension from the axial passage toward the fluid circuit. A third radial path, the extension comprising a second circumferential groove circumferentially intersecting the third radial path, whereby the shaft is rotated relative to the fluid circuit The fluid pressure clutch of claim 5, wherein a circumferential groove of 2 maintains fluid communication between the fluid circuit and the third radiation path.

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