JPH10193995A - Power transmission gear for four-wheel drive vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a bend angle of a wheel driving shaft to the minimum, increase the degree of freedom of setting a wrapping type power transmission means, and also effectively decrease the noise caused by the operation thereof, in a two-axle type power transmission gear for a four-wheel drive vehicle. SOLUTION: A power transmission gear for a four-wheel drive vehicle comprises a transverse engine En, a transmission Tm disposed in series to the engine, a clutch 3 transmitting the engine power to a speed changing mechanism, a front wheel axle 8 transmitting the driving power received with an input ring gear 6 disposed in parallel to an output shaft 4 of the transmission to a front wheel driving axle 9, and a transfer shaft 12 disposed in parallel to the front wheel axle and transmitting the driving power transferred thereto to the rear wheel axle 23, and the transfer shaft is connected with the front wheel axle by a chain 15. In this case, the input ring fear 6 is arranged at the transmission side of the front axle and the chain 15 is arranged at the engine side of the same front wheel axle, getting a protrusion 2Ae adjacent to the engine and injecting toward the rear side of the car body of a clutch housing 2A in between.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power transmission device for a four-wheel drive vehicle.

[0002]

2. Description of the Related Art Conventionally, as a four-wheel drive vehicle of a type in which a transmission is arranged in series with a horizontal engine, a first axle (for example, a so-called so-called "axle") which is arranged in parallel with an output shaft of the transmission and receives driving force. In the case of an FF type automobile, the driving force is directly taken out from the front wheel axle).
A one-axis type is known. However, the first
The layout of the axle is basically determined by the mounting position of the engine and the transmission, the wheel tire diameter, and the like. For this reason, in the case of the above-described one-axle type, the first axle side and the second axle (the rear axle in the case of the FF type automobile)
The vertical position of the propeller shaft connecting to the side is inevitably higher, and the floor tunnel that covers the upper part of the propeller shaft also protrudes higher toward the passenger compartment side, which adversely affects the livability in the passenger compartment. Problem arises.

Therefore, a transfer shaft as a kind of intermediate shaft for transmitting power is arranged in parallel with the first axle, and power is transmitted to a propeller shaft via the transfer shaft. A shaft type power transmission device has been proposed. In the case of the two-shaft type, the vertical position of the transfer shaft is set lower than the first axle by a fixed value or more, so that the position of the propeller shaft can be suitably lowered. The problem can be solved.

[0004] As a power transmission device for such a two-shaft type four-wheel drive vehicle, the applicant of the present invention disclosed in Japanese Patent Application Laid-Open No. 5-305834 discloses a conventional gear transmission for transmitting power between a first axle and a transfer shaft. A structure has been disclosed in which a power transmission means of a wrapping type such as a chain or a belt is used instead of transmission by a mechanism. By using such a winding type power transmission means, the degree of freedom of setting the reduction ratio of the transfer shaft can be increased as compared with the case of the conventional gear mechanism. As well as ensuring a higher height, a more compact layout of the differential device and the torque transmission mechanism can be achieved.

Further, as a gear for transmitting power by converting the direction by 90 degrees between the transfer shaft and the propeller shaft and between the propeller shaft and the rear wheel axle, a hypoid gear, which is a kind of torsion bevel gear, is usually used. Although the transfer axle rotates in the same direction as the first axle with the use of the above-mentioned wrapping type power transmission means,
For both front and rear hypoid gears, the forward rotation tooth surface can be used when the vehicle moves forward by far overwhelming frequency,
This is more advantageous for noise problems and gear life.

[0006]

A wheel drive shaft having one end (inner end) connected to the axle and rotatably supporting the wheel at the other end (outer end) has a basic height at the inner end. Is determined by the mounting position of the engine and transmission, etc.
On the other hand, the height on the outer end side is basically determined by the tire diameter. The wheel drive shaft is generally extended in the vehicle width direction so as to be inclined obliquely downward and obliquely outward with respect to the axle.

FIG. 4 is an explanatory view schematically showing a bending angle of a wheel drive shaft. As can be seen from FIG.
The bend angle of the wheel drive shaft Sw with respect to d increases as the mounting position of the engine En and the transmission Tm increases (θ ₂ >
θ ₁ ). It is known that as the angle of bend increases, the torque fluctuation at the time of starting the vehicle or the like increases, and so-called torque steer tends to occur. Therefore, in order to ensure good running performance at the time of starting, it is required to minimize the bend angle of the wheel drive shaft Sw. In particular, in the case of an off-road type vehicle, for example, as shown by a broken line in the figure, it is required to secure a minimum ground clearance H larger than a certain value. It is important how to keep this small.

As is well known, a clutch device as a transmission device for transmitting the power of the engine to the transmission mechanism is provided on the side closest to the engine (that is, between the engine and the transmission mechanism) in the transmission apparatus. Alternatively, a torque converter is arranged, and the case body (generally,
The clutch housing or the torque converter housing) has a considerably larger diameter than other parts that follow it (such as a transmission housing housing a transmission mechanism). When a transmission is arranged in series in a horizontal engine, the end of the casing of the transmission device (clutch device or torque converter) on the engine side (that is, the portion adjacent to the engine) is usually
In a plan view, it protrudes rearward from the engine outer shape by a certain degree or more (that is, toward the first axle side).

Therefore, in the case where the power transmission between the first axle and the transfer shaft is performed by a wrapping type power transmission means such as a chain or a belt, the wrapping type power transmission device as disclosed in the above-mentioned conventional publication is used. The transmission means, together with the final ring gear (in other words, the input ring gear for the drive mechanism of the first shaft) that constitutes the final reduction unit of the transmission, is closer than the engine-side end of the transmission case body (that is, the transmission unit). If the casing portion of the device is disposed on the transmission side (rather than the portion of the casing portion protruding to the first axle side adjacent to the engine), the position and the radial size of the chain sprocket or the belt pulley are limited accordingly.

By the way, a transfer unit including a hypoid gear for transmitting power between a transfer shaft and a propeller shaft and a meshing portion thereof and the above-mentioned transmission use different oils. That is, in the case of the transmission oil used in the transmission, in addition to the function as the lubricating oil for the sliding parts of the internal mechanism, the function as the hydraulic oil for generating the hydraulic pressure for driving the operating components such as the valve spool is provided. However, in the case of the transfer unit, a high-viscosity oil is used mainly for lubrication of the hypoid gear, which is required to have high load resistance. Is done. Incidentally, in the case of a chain which is a kind of a wrapping type power transmission means, generally, lubricating oil of either high or low viscosity can be used. However, in the case of this chain, there has been a drawback that noise during operation is generally greater than that of a gear.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and a so-called two-shaft type power transmission device in a four-wheel drive vehicle has a wheel drive shaft with a bending angle as small as possible and a wrapping power transmission. It is an object of the present invention to ensure the degree of freedom of setting of the means and to effectively reduce noise when the wrapping power transmission means is operated.

[0012]

For this reason, the invention according to claim 1 of the present application (hereinafter referred to as a first invention) includes a horizontal engine having an output shaft arranged in the vehicle width direction, A transmission arranged in series with an output shaft of the engine, a transmission device disposed between a transmission mechanism of the transmission and the engine, and transmitting power of the engine to the transmission mechanism;
A first axle arranged in parallel with the output shaft of the transmission, receiving a driving force from the output shaft via an input ring gear, and transmitting the driving force to the wheel drive shaft; And a transfer shaft for transmitting the power of the first axle to the second axle, wherein the transfer shaft and the first axle are connected via a wrapping type power transmission means. In the power transmission device for a wheel drive vehicle, the input ring gear is disposed on the transmission side with the casing portion of the transmission device protruding toward the first axle side adjacent to the engine on the first axle. ,
The above-mentioned wrapping power transmission means is arranged on the engine side.

Further, the invention according to claim 2 of the present application (hereinafter referred to as “the invention”)
The second invention is characterized in that, in the first invention, a differential device between left and right wheels is disposed on an inner peripheral side of the input ring gear on the first axle. It is.

Further, the invention according to claim 3 of the present application (hereinafter referred to as “the invention”)
According to a third aspect of the present invention, in the first or second aspect, the wrapping type power transmission means is a chain type, and the input ring gear is disposed in a case of a transmission, while The hook-type power transmission means is arranged in a transfer case in which a gear attached to the transfer shaft and a meshing portion thereof are housed.

[0015]

According to the first aspect of the present invention,
On the first axle, the input ring gear is disposed on the transmission side with the casing portion of the transmission device protruding toward the first axle side adjacent to the engine, and the wrapping power is disposed on the engine side. Since the transmission means is disposed, the position of the connecting portion between the first axle and the wheel drive shaft can be set inward of the vehicle width as compared with a case where both are conventionally disposed on the transmission side. Become. As a result, the bend angle of the wheel drive shaft can be reduced,
The running performance at the time of starting the vehicle can be improved, for example, the torque fluctuation at the time of starting the vehicle can be suppressed and the torque steer can be hardly generated. In addition, in this case, since the wrapping power transmission means is disposed on the engine side, it is possible to avoid the projecting portion of the casing of the transmission device from protruding toward the first axle adjacent to the engine. Thus, the degree of freedom in setting the position and radial size of the chain / sprocket or belt / pulley can be increased.

According to the second aspect of the present invention, basically, the same effects as those of the first aspect can be obtained. In addition, since the differential device between the left and right wheels is disposed on the inner peripheral side of the input ring gear on the first axle, it constitutes the final reduction portion of the transmission and originally has a relatively large diameter. By effectively utilizing the inner space of the input ring gear, the differential device having a relatively large volume can be laid out.

Further, according to the third aspect of the present invention, basically the same effects as those of the first or second aspect can be obtained. In addition, in the case where the wrapping power transmission means is a chain type, the wrapping power transmission means (chain) is filled with oil having a higher viscosity than the oil used in the transmission. Is arranged in the transfer case, the operating noise of the chain can be effectively attenuated by this high-viscosity oil to reduce the noise level accompanying the driving of the chain. The noise problem caused by the adoption can be solved.

[0018]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a skeleton diagram schematically illustrating a configuration of a power transmission device for a four-wheel drive vehicle according to the present embodiment. As shown in this figure, the four-wheel drive vehicle is, for example, a so-called FF type in which front wheels (not shown) can be constantly driven by an engine En disposed in a front portion of the vehicle, and is of a horizontal type. The engine En,
The output shaft 1 is arranged in the engine room with the output shaft 1 facing the vehicle width direction. On the output side of this engine En,
For example, a manual transmission type transmission Tm is arranged in series with the engine output shaft 1, and this engine output shaft 1 is connected to a clutch device 3 housed in a case 2 of the transmission Tm.

The transmission case 2 includes a clutch housing 2A housing a clutch device 3 and a transmission housing 2B housing a transmission mechanism following the clutch housing 2A. The clutch housing 2A includes an engine En.
The transmission case 2 is formed to be larger in diameter than other parts of the transmission case 2 (the transmission housing 2B and the like) in order to accommodate the clutch device 3 having a large volume and adjacent to the transmission case 2. When the transmission Tm is arranged in series with the engine En, the transmission Tm projects rearward from the outer shape of the engine En by a predetermined amount in a plan view, and an end on the engine En side (that is, adjacent to the engine En). The end) forms an overhang 2Ae.

An output gear 5 is connected to an output shaft 4 of the transmission Tm.
The output gear 5 is meshed with a relatively large-diameter ring gear 6, which constitutes the final reduction unit of the transmission Tm (in other words, becomes the input gear for the front wheel drive mechanism). ing. The ring gear 6 (input ring gear) is provided on the front wheel axle 8 at the end of the transmission case 2 on the engine En side (that is, the projecting portion 2A of the clutch housing 2A toward the rear of the vehicle body adjacent to the engine En).
It is arranged on the transmission Tm side from e). In the present embodiment, the ring gear 6 (input ring gear) is fixed to the outer peripheral portion of the front differential 7. That is, the differential device 7 between the left and right front wheels is disposed on the inner peripheral side of the large-diameter input ring gear 6 by effectively utilizing the inner space, and the differential gear 7 having a relatively large volume is provided. As for the arrangement of the device 7, an efficient layout is realized.

Then, a pair of left and right first axles 8 (front wheel axles) for driving the front wheels via the front differential 7.
Extend in the vehicle width direction (that is, in parallel with the transmission output shaft 4). Each front wheel axle 8 is rotatably supported by bearings indicated by reference numerals △ and に お い て in the figure. Also, at the shaft end of each of these front wheel axles 8,
Front wheel drive shafts 9 for driving the front wheels are connected via universal joints 11, respectively. Thus, a so-called FF drive system that can constantly drive the front wheels is configured.

Next, a power transmission system for variably controlling the drive torque distribution of the rear wheels will be described. A transfer shaft 12 rotatably supported behind the front wheel axle 8 by a predetermined distance is arranged in parallel with the front wheel axle 8. As can be clearly understood from FIG. 2, the transfer shaft 12 is set so that its vertical position is lower than the front wheel axle 8 by a predetermined amount, and accordingly, the driving force is directly taken out from the front wheel axle. The vertical position of the propeller shaft 21 (central axis Lp) can be made lower than that of the single-shaft type. The front axle 8 and the transfer axle 12 are connected by a wrapping power transmission means. That is, the first sprocket 13 is fixed at a predetermined position in the middle of the front wheel axle 8, while the second sprocket 14 corresponding to the first sprocket 13 is located at a position on the right side of FIG. Are fixed, and both sprockets 13,1
A chain 15 is wound and stretched between the four.

A hypoid-type front ring gear 16 (front hypoid ring gear) is fixed to the transfer shaft 12 at a position closer to the center than the second sprocket 14 such that its tooth surface is directed to, for example, the left side in FIG. ing. The front hypoid ring gear 16
Is more preferably arranged such that the direction of the tooth surface is in a direction facing the tooth surface of a rear hypoid ring gear described later. The front hypoid / ring gear 16 meshes with a front hypoid / pinion gear 17 so that the driving force from the transfer shaft 12 is converted by 90 degrees and then transmitted to the propeller shaft 21 via the clutch 31. .

As is well known, in a hypoid type gear set (a combination of the hypoid ring gear 16 and the hypoid pinion gear 17), the respective rotation center axes of the ring gear 16 and the pinion gear 17 are offset. Therefore, the hypoid
The vertical position of the center axis of the pinion gear 17 can be lowered. That is, as can be clearly understood from FIG. 2, the vertical position of the central axis Lp of the propeller shaft 21 is set lower than the central axis of the transfer shaft 12 by a predetermined dimension F corresponding to the offset amount. Thus, the engine room is provided continuously in the wall Ds (dash panel) after of R _E cabin floor tunnel Tn covering above the propeller shaft 21 R
_The height of the overhang to the _C side is kept low, and the livability in the passenger compartment _RC is well secured.

The gear shaft 17s of the hypoid pinion gear 17 is connected to the clutch 31 which is operated by, for example, hydraulic pressure or electromagnetic attraction, and is connected to one of the working members. The front end side of the propeller shaft 21 is connected. In the present embodiment, the clutch 31 is, for example,
By controlling the operation according to the vehicle speed, the selection of the four-wheel drive, the accelerator opening, etc., the rear wheels as well as the front wheels can be actively controlled. Hypoid ring gear 1
6, case body 1 of transfer unit Tf including hypoid pinion gear 17, transfer shaft 12, and the like
A clutch case 32 accommodating the clutch 31 is integrally connected to a rear end of the transfer case 9 (transfer case). Also, the front left side of the transfer case 19
It is connected to a part of the transmission case 2. The structure and layout of the transfer case 19 will be described later.

A pair of left and right second axles 23 (rear wheel axles) are connected from the propeller shaft 21 via a rear differential 22.
The driving force is transmitted to the universal joint 2 by the driving force.
The right and left rear wheel drive shafts 25 respectively connected to the rear wheel axle 23 via the drive wheels 4 are rotationally driven. That is, the gear shaft 27 s of the rear hypoid pinion gear 27 is connected to the rear end side of the propeller shaft 21, and the rear hypoid pinion gear 27 is fixed to the outer peripheral portion of the rear differential 22. Rear hypoid
The gear is orthogonally engaged with the ring gear 26. Thus, the driving force from the propeller shaft 21 is converted by 90 degrees and transmitted to the left and right rear wheel axles 23.

The rear hypoid ring gear 26 includes:
More preferably, it has a tooth portion twisted in the same direction (for example, right-hand twisting direction) as the tooth portion of the front hypoid ring gear 16, and the direction of the tooth surface thereof is opposite to the tooth surface of the front hypoid ring gear 16. (Rightward direction in FIG. 1). More preferably, the front and rear hypoid and pinion gears 17 and 27 are also formed such that each tooth portion is twisted in the same direction (for example, a left twist direction). The forward tooth surfaces of the hypoid ring gears 16 and 26 and the hypoid pinion gears 17 and 27 are used during forward traveling of the vehicle, which is overwhelmingly frequent.
Further, the front wheel axle 8 and the transfer shaft 12 are connected by a chain 15 as a wrapping type power transmission means and rotate in the same direction. Therefore, the gear ratio is appropriately selected, and the front and rear hypoid / ring gears 16 and 26 and the hypoid The pinion gears 17, 27 can be commonly used.

In the present embodiment, as described above, the clutch case 32 is integrally connected to the rear end of the transfer case 19, while the front left side of the transfer case 19 is Connected to the department. Hereinafter, the structure and layout of the transfer case 19 will be described. As shown in detail in FIG. 3, in the transfer case 19, in addition to the hypoid ring gear 16, the hypoid pinion gear 17 and the transfer shaft 12, a part of the front wheel axle 8 and the wrapping power transmission means (the chain 15). And both sprockets 1
3, 14) are stored in the clutch case 32.
Is transferred to the transfer case 19 by a plurality of screw members 33.
At the rear end. On the other hand, at the front left end portion of the transfer case 19, the outer peripheral portion is located on the right side of the case body 10 (differential case) of the front differential device 7 which constitutes a part of the transmission case 2 (a part of the clutch case 2A). It is fitted to the inner periphery of the opening. And the differential case 1
0 and the transfer case 19, a seal member 20
Is sealed in a liquid-tight manner.

Different types of oil are used in the transmission case 2 and the transfer case 19. That is, in the case of the transmission oil used for the transmission Tm, in addition to the function as a lubricating oil for sliding parts of the internal mechanism, the function as a hydraulic oil for generating hydraulic pressure for driving an operating component such as a valve spool, for example. Is selected because of the required. In the present embodiment, for example, the kinematic viscosity at a temperature of 100 ° C. [mm
² / s (cSt: centistokes)] of about 6.0 or more or about 7.0 or more and relatively low viscosity.
On the other hand, in the transfer case 19, a hypoid gear (hypoid gear) requiring high load resistance is required.
It is necessary to use high-viscosity oil for lubrication of the ring gear 16 and the hypoid / pinion gear 17). In the present embodiment, for example, the kinematic viscosity at a temperature of 100 ° C. [mm
² / s (cSt)] is 24.0 or more. still,
In the transfer case 19, a dedicated oil supply hole 19a and an oil discharge hole 19b are provided.

In the present embodiment, while the input ring gear 6 is disposed in the transmission case 2, the above-mentioned wrapping power transmission means (the chain 15 and the two sprockets 13, 14)
Is disposed in the transfer case 19, and the high-viscosity oil is applied as lubricating oil to the wrapping power transmission means. Thereby, the operation noise of the chain 15 is effectively attenuated by the high-viscosity oil,
The noise level associated with driving the chain 15 is greatly reduced.

In the present embodiment, the chain 15 and the two sprockets 13 and 14 are arranged on the front wheel axle 8 at the end of the transmission case 2 on the engine En side (that is, adjacent to the engine En of the clutch housing 2A). The protruding portion 2Ae) on the side of the front axle 8 is located closer to the engine En. That is, as described above, when the transmission Tm is arranged in series with the engine En, the clutch housing 2A of the transmission 2 moves the vehicle rearward by a predetermined amount from the outer shape of the engine En in a plan view (the front wheel axle 8). Side), but the input ring gear 6
On the front wheel axle 8, the engine En of the transmission case 2
Side of the engine E of the clutch housing 2A
n is located closer to the transmission Tm than the overhang 2Ae (toward the front wheel axle 8) to the rear of the vehicle body adjacent to n, while the wrapping power transmission means (chain 15 and both sprockets 13, 14) is It is arranged on the engine En side as described above.

By adopting such a layout,
Conventionally, the entire length of the front wheel axle 8 can be reduced as compared with the case where both the input ring gear and the wrapping type power transmission means are arranged on the transmission side, and the front wheel axle 8 and the front wheel drive shaft 9 (Ie, the universal joint 11) can be set inward of the vehicle width. As a result, the bending angle of the front wheel drive shaft 9 can be reduced. That is, referring to FIG. 4, if the length of the axle Sd is reduced from the state shown by the dashed straight line in FIG. 4 (the state in which the bend angle of the wheel drive shaft Sw is θ ₂ ), two points in FIG. As shown by the chain line, the axle Sd and the wheel drive shaft Sw
To the vehicle width inward (from the connecting part J2 to the connecting part J3
F), the bend angle of the wheel drive shaft Sw with respect to the axle Sd becomes small (θ ₃ <θ ₂ ).

As a result, it is possible to suppress the occurrence of so-called torque steer by minimizing the torque fluctuation at the time of starting the vehicle or the like, and to improve the running performance at the time of starting. Moreover, in this case, the wrapping power transmission means (the chain 15 and the two sprockets 13 and 14) is disposed closer to the engine En than the end of the clutch housing 2A on the engine side. Can be disposed avoiding the overhang 2Ae to the rear of the vehicle body (toward the front wheel axle 8) adjacent to the vehicle, and a high degree of freedom in setting the positions and radial sizes of the sprockets 13 and 14 can be obtained. is there.

Although the above-described embodiment has been applied to a vehicle provided with a manual transmission type transmission, the present invention is not limited to such a case.
The present invention can be effectively applied even when the transmission is of an automatic transmission type. In addition, the present invention is not limited to the above embodiments, and without departing from the gist thereof,
It goes without saying that various improvements, modifications or changes in design are possible.

[Brief description of the drawings]

FIG. 1 is a skeleton diagram schematically showing a configuration of a power transmission device for a four-wheel drive vehicle according to an embodiment of the present invention.

FIG. 2 is an explanatory side view of a power transmission device of the four-wheel drive vehicle.

FIG. 3 is an explanatory cross-sectional view showing an internal structure of a transfer case of the power transmission device.

FIG. 4 is an explanatory view schematically showing a bending angle of a wheel drive shaft.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Engine output shaft 2 ... Transmission case 2A ... Clutch housing 2Ae ... Clutch housing overhang 3 ... Clutch device (transmission device) 4 ... Transmission output shaft 6 ... Input ring gear 7 ... Front differential device 8 ... Front wheel axle (First axle) 9 Front wheel drive shaft 12 Transfer shaft 13 First sprocket 14 Second sprocket 15 Chain 16 Front hypoid / ring gear 17 Front hypoid / pinion gear 19 Transfer case 23 Rear wheel axle 2 axles) En: engine Tm: transmission

Claims (3)

[Claims] 1. A transverse engine having an output shaft oriented in a vehicle width direction, a transmission arranged in series with an output shaft of the engine, a transmission mechanism of the transmission, and the engine A transmission device disposed between the transmission device and the transmission mechanism for transmitting the power of the engine to the transmission mechanism; a transmission device disposed in parallel with an output shaft of the transmission device, receiving a driving force from the output shaft via an input ring gear; And a transfer axle arranged in parallel with the first axle and for transmitting the power of the first axle to the second axle. A power transmission device for a four-wheel drive vehicle, wherein the power transmission device is connected to one axle via a wrapping type power transmission means, the first axle being adjacent to the engine in a casing portion of the transmission device on the first axle. Overhang to side A power transmission device for a four-wheel drive vehicle, characterized in that the input ring gear is disposed on the transmission side and the wrapping power transmission means is disposed on the engine side with a portion therebetween. 2. The power of a four-wheel drive vehicle according to claim 1, wherein a differential device between left and right wheels is disposed on an inner peripheral side of the input ring gear on the first axle. Transmission device. 3. The wrapping power transmission means is of a chain type, and the input ring gear is disposed in a case of a transmission, while the wrapping power transmission means is mounted on the transfer shaft. The power transmission device for a four-wheel drive vehicle according to claim 1, wherein the power transmission device is disposed in a transfer case in which the gear and a meshing portion thereof are housed.