IHMT transmission in real world

[ericm979]

The Fendt Vario transmission is a CVT. The I-HMT is not a CVT.

They're both Continually Variable Transmissions, in the generic sense of changing ratios without steps across a range. In the automotive world and some others, "CVT" has become associated with one particular type of CVT that uses belts or chains and variable size pulleys. But that's not the only type of generic CVT. A HST is a CVT too for example, and so is IHMT.

Regardless of the wording used in the advertisement, Vario, it is not the same. The CVT has belts, the I-HMT has a hydraulic pump and motor that lock together. Some of the features are similar, but the transmissions are different.

This is a pretty understandable explanation of the Fendt CVT:

It combines gear and HST like IHMT... no belts or chains like an automotive-specific type CVT.

 

[freightboy]

I'm not sure where the idea came from, but it works much differently. That has a separate pump and motor which is not on the same shaft, the I-HMT shares a shaft. The pump and motor are what makes the transmission, and they are completely different. The website says it is a CVT: Vario Drive
The I-HMT locks the pump and motor together much like a torque converter when it is in the working range. The Fendt transmission has a separate pump and motor as illustrated in your post, therefore they do not lock together. They are both step-less, that is similar. They operate much differently and the I-HMT is not a "scaled down version".

 

[ptsg]

I'm not sure where the idea came from, but it works much differently. That has a separate pump and motor which is not on the same shaft, the I-HMT shares a shaft. The pump and motor are what makes the transmission, and they are completely different. The website says it is a CVT: Vario Drive
The I-HMT locks the pump and motor together much like a torque converter when it is in the working range. The Fendt transmission has a separate pump and motor as illustrated in your post, therefore they do not lock together. They are both step-less, that is similar. They operate much differently and the I-HMT is not a "scaled down version".

We have been in this road before and you still haven't taken the time to read or watch a video (like the one above) to learn how the Vario works or to learn that CVT is not only called to a transmission that uses a belt or a chain to vary the speeds, just like Eric explained.

About the only difference, is the Fendt puts the motor and pump on different locations, while Yanmar puts them inline but those still works exactly the same way. They really have to, that's how this transmission works.

Yes, the Vario also locks the pump and motor together. You would know that if you watched the video. That's the entire principle of operation of these types of transmissions.

 

[bsekf]

Thank you all and I am looking forward to driving one. However, I got a quote for $51K and that is just too much for a compact tractor regardless of the convince.

 

[ptsg]

Thank you all and I am looking forward to driving one. However, I got a quote for $51K and that is just too much for a compact tractor regardless of the convince.

It's indeed a great transmission to have but it doesn't come with an hefty price.

 

[freightboy]

PTSG, we have been down this road. I work with the I-HMT on a day to day basis and know it is different. They do have some similarities, but so does every other transmission. I watched the video several times, it is different. I have admitted in the past that I don't know a great deal about the Fendt transmission, but I do know enough to know the I-HMT isn't a "scaled down version". The pump and motor on the same shaft is key to how the I-HMT works, the Fendt doesn't have that. Much different.

 

[ptsg]

PTSG, we have been down this road. I work with the I-HMT on a day to day basis and know it is different. They do have some similarities, but so does every other transmission. I watched the video several times, it is different. I have admitted in the past that I don't know a great deal about the Fendt transmission, but I do know enough to know the I-HMT isn't a "scaled down version". The pump and motor on the same shaft is key to how the I-HMT works, the Fendt doesn't have that. Much different.

Just because the pump and motor are on a different layout, doesn't mean the rest is different. It's still the same principle of operation of the Vario, still functions the same.

Kanzaki, the maker of the iHMT puts the pump and motor inline, while the Vario spreads the pump and motor but connects them with gears. There is still a planetary gear set in the system, since that's the key for this transmission to work the way it does.

Too bad there is very little info about the iHMT out there other than some pictures showing the pump and motor inline, not the rest of the system. That would have helped clear a lot of the things up.

 

[airbiscuit]

 

[freightboy]

Just because the pump and motor are on a different layout, doesn't mean the rest is different. It's still the same principle of operation of the Vario, still functions the same.

Kanzaki, the maker of the iHMT puts the pump and motor inline, while the Vario spreads the pump and motor but connects them with gears. There is still a planetary gear set in the system, since that's the key for this transmission to work the way it does.

Too bad there is very little info about the iHMT out there other than some pictures showing the pump and motor inline, not the rest of the system. That would have helped clear a lot of the things up.

That is the transmission. The pump and motor are both on the same shaft, that is what allows it to hydraulically lock together, that is what provides less power loss than a traditional hydrostatic transmission. That is the entire I-HMT that is on the display stand.
Kanzaki is a Yanmar company. Tuff Torq and Transaxle Manufacturers of America are as well.
The pump is turned by the input shaft. There is a single swash plate that is controlled by a solenoid for position. Forward and reverse are controlled by 3 solenoids on the right side of the tractor. There is an outer shaft over the input shaft that the motor turns which are attached to the gears to make the wheels turn.
Basically, the pump and motor on the same shaft is the basis for the operation and why it differs from other transmissions on the market.

 

[ptsg]

That is the transmission. The pump and motor are both on the same shaft, that is what allows it to hydraulically lock together, that is what provides less power loss than a traditional hydrostatic transmission. That is the entire I-HMT that is on the display stand.
Kanzaki is a Yanmar company. Tuff Torq and Transaxle Manufacturers of America are as well.
The pump is turned by the input shaft. There is a single swash plate that is controlled by a solenoid for position. Forward and reverse are controlled by 3 solenoids on the right side of the tractor. There is an outer shaft over the input shaft that the motor turns which are attached to the gears to make the wheels turn.
Basically, the pump and motor on the same shaft is the basis for the operation and why it differs from other transmissions on the market.

So does the Vario and all the other CVTs that combine the HST with a mechanical transmission. They all lock the pump and motor together... That's the entire concept of this type of transmission. I really don't understand why you keep saying they're different.

You're missing the planetary gear set though. It has to have one as this is the key for this type of transmission to work at the efficiency levels they rate it to.