ADJUSTABLE FACE PLATE FOR HYDRAULIC PUMP OR MOTOR
The invention relates to a hydraulic device as described in the preamble of claim 1. Such a device is known, inter alia, from WO 9731165 or from NL 1008256 - which is not a prior publication - of the same applicant, both of which relate to a hydraulic pressure transformer. The disadvantage of the known device is that in the known device energy loss occurs at great volume flows, with the result that the efficiency of the device is low. It has been found that a considerable part of the loss occurs during the closing of the inlet to or outlet from the fluid chamber. In the hydraulic device the inlet to or outlet from the fluid chamber is closed or opened over a large part of the working area where the volume of the fluid chamber is changing rapidly. As a result of this, during the opening or closing of the fluid chamber great flow velocities can occur through the small surface area of the closing or opening aperture between the rotor port and the face plate port . These locally high flow velocities cause a considerable part of the losses, and it is important to make the duration of their occurrence as short as possible. In the case of the known device with the round rotor ports and the rounded face plate ports, during, for example, the shutting off of the rotor port with the rib, an ever-decreasing lens-shaped aperture is formed, through which, as a result of the change in the volume of the fluid chamber during opening or closing, liquid flows at ever-increasing velocity. The high flow velocity occurring causes the energy loss .
The object of the invention is to avoid the above disadvantage, and to that end the known device is designed as claimed in the characterizing clause of claim 1. Designing the switching means as quick-acting valves ensures that the high flow velocity occurs during a small rotor rotation, with the result that the losses are limited.
According to a further improvement, the hydraulic device is designed as claimed in claim 2. By this measure, the pressure build-up in the fluid chambers is limited, so that the flow velocity remains lower during opening or closing of the valves.
The invention also relates to a hydraulic device designed as claimed in claim 3. In this case, the switching means are in the form of a face plate with face plate ports which interact with rotor ports . By making the edges of the rotor ports and the walls an identical shape, it is ensured that during rotation of the rotor the flow over the entire common breadth is shut off simultaneously, and the duration of flow occurring at high velocity is very short, with the result that the losses are limited. According to a further improvement, the device is designed as claimed in claim 4. By this measure, the edges of the rotor port and the face plate port are formed by the line of intersection of a straight surface and the boundary surface. Such an edge can be simple in design and sharp, so that small cracks are avoided. This ensures that fewer losses occur.
According to a further improvement, the device is designed as claimed in claim 5. By this measure, while the surface area of the aperture to the fluid chamber remains the same, the duration of high flow velocity occurring is shortened further, with the result that fewer losses occur .
According to a further improved embodiment, the hydraulic device is designed as claimed in claim 6. By this measure, a pressure build-up in the fluid chambers is prevented in a simple manner, with the result that the efficiency increases, particularly at high speeds of rotation of the rotor.
The invention is explained below with reference to a number of exemplary embodiments with the aid of a drawing.
In the drawing:
Figure 1 shows a diagrammatic cross section of a hydraulic pressure transformer;
Figure 2a shows the view of the face plate of a pressure transformer from Figure 1 according to the prior art;
Figure 2b shows the view of the rotor of a pressure transformer from Figure 1 according to the prior art;
Figure 3a shows the view of the face plate of a pressure transformer from Figures 1 and 2 according to a first embodiment of the invention;
Figure 3b shows the view of the rotor of a pressure transformer from Figures 1 and 2 according to the first embodiment of the invention;
Figure 4 shows diagrammatically how the face plate ports and the rotor ports from Figures 3a and 3b interact;
Figure 5a shows the view of the face plate of a pressure transformer from Figures 1 and 2 according to a second embodiment of the invention;
Figure 5b shows the view of the rotor of a pressure transformer from Figures 1 and 2 according to the second embodiment of the invention; Figure 6 shows diagrammatically how the face plate ports and the rotor ports of a third embodiment interact;
Figure 7 shows diagrammatically how the face plate ports and the rotor ports of a fourth embodiment interact; and Figure 8 shows the efficiency of the hydraulic pressure transformer as a function of the speed of rotation of the rotor;
Figure 9 shows an embodiment corresponding to the first embodiment, in which the wall is narrower than the rotor port;
Figure 10 shows an exemplary embodiment corresponding to the third embodiment, in which the wall is narrower than the rotor port; and
Figure 11 shows an exemplary embodiment corresponding to the fourth embodiment, in which the wall is narrower than the rotor port .
In the various figures corresponding parts are indicated as far as possible by the same reference numerals .
Figures 1 and 2 show a hydraulic pressure transformer 1, the operation of which corresponds to that described in WO 9731185, the text of which is deemed to have been inserted here . The hydraulic pressure transformer 1 has a rotor housing 4 containing bearings 2 in which a rotary shaft 3 can rotate . Attached to the rotary shaft 3 are plungers 5, which can slide in the fluid chambers 7 of a rotor 6. The rotor 6 can rotate freely about its axis of rotation in the rotor housing 4. A face plate housing 10, in which a face plate 8 can rotate, is fixed on the rotor housing 4. The face plate 8 can be rotated by means of an adjusting shaft 9. The face plate housing 10 is provided with a first line connection 11, a second line connection 12 and a third line connection (not shown) . The line connections are connected to the fluid chambers 7 by means of channels, which channels run through the face plate housing 10, the face plate 7 and the rotor 6. The rotor 6 and the face plate 8 are pressed against each other in a sealing manner in a boundary surface 13 by the oil pressure in the fluid chambers 7.
Three face plate ports 14 are provided in the face plate 8 (see Figure 2a) , with three walls 15 between them. Each face plate port 14 according to the prior art has an inner radius 17, an outer radius 16 and a circular side edge 18. The rotor 6 is provided with seven rotor ports 19, each of which is in communication with a fluid chamber 7. During the rotation, the fluid chamber 7 goes into communication with a face plate port 14 , is sealed off by a wall 15, and subsequently goes into communication with the next face plate port 14. The shutting off of a fluid chamber 7 by means of a wall 15 of a face plate 8 is commonly applied in a corresponding manner in the case of the known hydraulic plunger pumps and plunger motors. In this case there is generally a face plate 8 with two face plate ports 14, and the position of the walls 15 corresponds to the greatest or the smallest volume of the fluid chamber 7, positions in which the speed of changing of the volume of the fluid chamber 7 is minimal . In those
ω ω t t H H in o in o ui o LΠ tr rt CO CO ti z J ti P 0 Hi CO P Ω ti 0 0 Hi PJ Hi TJ ti CO rt CO Ω Ω ιp 0 rt ft TJ Ω Hi ιp CO O o o μ- μ- 0 μ- & 0 μ- ti PJ tr μ- o 0 l-h ti PJ rt 0 O 0 tr ET tr tr ti tr ti ø ET H1 H μ-
M P- 3 rt H PJ rt ti Ω 0 co 3 ft Ω H CO rt 0 Φ 0 0 PJ Φ φ PJ 3 J 0 PJ rt
Φ rt Φ 0 o TJ 0 φ φ ti rt 3 J (t Ω Φ rt t-1 μ- O z ^ CO PJ ft ø TJ 0 μ- a 0
CO tr H1 ti rt ti Ω Φ rt PJ 0 rt tr H ø- ^ rt ti CO Hi 0 φ 4 ft tr Hi CO ιp 0 PJ φ φ rt CO Φ rt CO TJ ø 0 μ- PJ 0 TJ Φ μ- PJ Pi φ Φ H Hi 0 Φ PJ rt
0 Pi PJ TJ μ- P- TJ μ- CO H Ω Ω ø rt CO H tr 0 oo ET Ω μ- ti l-h 0 0 ti CO Ω M μ- 1—1
0 PJ I H ø 0 3 0 0 J μ- Φ z iQ φ J M *< ø 0 Φ ø H ø co ti ø Ω ft ti μ- TJ rt φ PJ Z 0 rt CO 0 Φ Ω rt ti PJ 0 Φ Hi rt μ- ti TJ tϋ •i H Hi μ- H H • ET M 0
X Φ ET Φ ti 0 H P g 3 ø PJ t μ- Φ 0 rt μ- μ- *. z 0 Φ 0 ^ ø r CO tr o t 0 ft 0 ø PJ tr 0 i < rt tr ø Φ μ- μ- rt Ω μ- Ω •i rt rt φ H CO CO H J Φ H 0 CQ TJ μ- ^ rt rt φ TJ φ ø PJ tr ? CO < α tr 0 ET φ μ- μ-
0 μ- H rf* 0 vo rt 0 rt rt 0 ti o ET Z CO rt •§ Φ PJ φ PJ μ- ti Φ ti ø rt
H- Hi 0 *< - φ Φ PJ ti μ- tr ET ti 0 ti PJ Z tr μ- rt Φ ti ¥ μ- H Ω CO ø Hi φ 0 α ti ti ø rt ø ti Φ PJ rt 0 PJ μ- rt tr Φ Hi P 0 tr * 0 CO Z μ-
CO ti 0 Z 0 I 0 0 rt ιp 0 TJ P. H Ω ø μ- σi CO μ- Ω PJ Φ Ω ti μ- - tr Q μ- 0 rt φ < μ- CO φ rt rt H PJ 0 rt Ω H M tr PJ co ti Ω μ- ti tr rt μ-
Pi rt ET Pi Φ rt H PJ J 0 Φ> Ω Pi PJ ϋ tr 0 *» CO rt PJ ω O tr rt PJ rt 0 tr Ω 0 φ PJ Φ IP ti tr J to rt rt < PJ Φ Ω rt Φ 3 • μ- H PJ φ Φ ø PJ rt PJ μ- φ ø ø- J Φ tr CO rt Φ H Φ μ- Φ J ø ti Φ 3 P. σi Pi g- P. g φ ti ιp Φ rt Ω 0
Ω μ- ti rt rt TS CO 0 ti 0 H tr 0 ι-3 φ • ti PJ φ Q' CO μ- φ μ- PJ Ω PJ
PJ 0 0 M tr tr PJ 0 0 P 0 ft TJ 0 0 ET 0 μ- 0 rt ø i φ < co i CO 0 0 J H
0 ø rt o φ φ O < rt rt Ω tr H *• 0 μ- Ω > rt ø Pi tr P ti Pi 0 φ ø CO CO
0 CO φ 0 0 ET ft Ω PJ PJ ø tr co 0 0 μ- φ 0 ø H CO tr rt CO φ φ rt tr O ti 0 Φ ti ti Φ tr 0 ø rt < P ti μ- CO ti ti 3 ω Pi PJ ti ø tr ; rt 0
Φ Hi ø Φ rt rt φ •i Φ μ- PJ Φ Ω ø μ- φ Φ ti tr μ- Ω μ- 3 0 μ- μ- ft ø
TJ rt CO tr ft ET rt Φ rt φ ti PJ PJ Ω P. TJ ø 0 •* 3 Ω ø φ rt rt ø ø ET 0 Ω z ft 0 rt μ- 0 Φ tr Φ ET 0 o tr tr J ≤ ; P. 0 μ- φ 0 PJ rt ft Φ 0 ιp tr ιp Φ H
0 tr ti tr ti M φ Φ rt rt Φ Φ 0 Φ rt CQ P. H rt 0 rt ø H μ- 0 Φ Z J 0 ti Φ rt φ φ ft ti μ- tr rt ti P CO - Φ Φ φ rt μ- rt ti 0 rt P. rt CQ Hi 0 tr <! ti CQ U1 f-r Φ Φ μ- ti ti φ Z ti rt 0 CO CQ P. 0 tr μ- tr Ml H Hi μ- 0 Φ Φ
Φ ti H Hi Ω ft ø ιp 0 Φ ti Φ 0 CO μ- ti ^ t H 0 φ oo rt PJ ø Φ ιp 0 Ω H CO α 0 o PJ 0 tr ft rt ET rt Φ rt ø Hi σ ft Z Φ vo tr Ω IP ti z rt ft ET ø CQ rt rt Ω 3 PJ μ- rt 0 tr ø 0 H PJ "• ET μ- ft Hi PJ PJ Ω CO Φ tr PJ tr 3 0 tr
PJ 0 M Φ 3 rt tr ti *• ti ti t-3 ti rf rt Ω - Φ rt to μ- 0 J ti ft 0 rt tr PJ Φ rt φ ft Φ ti Φ
Ω ti μ- o PJ φ - φ tr rt . tr φ ET H co Ω Φ ti 0 0 rt ø μ- ET φ
Ω . φ TJ 0 rt ø rt J φ ø- TJ φ z ti φ Φ φ Pi rt • 0 tr φ rt
0 H tr Pi Ω tr CO Pi Φ 0 ι-3 H tr 0 PJ 0 PJ PJ 0 μ- ft rt rt ø ^ ET TJ H
H t-3 μ- J tr φ O Φ 0 rt Pi ti tr ti μ- rt 0 Ω TJ Pi Pi ø tr μ- H ET P CO Φ Φ 0
PJ tr ø rt ti CO 3 tr μ- TJ rt φ PJ Ω 0 CQ CQ tr H1 PJ ιp Φ ø 0 Φ 0 ti ft ti J μ- rt μ- Φ Φ PJ μ- 3 ti rt co H P. Z tr ti μ- rt ft PJ TJ rt I Hi PJ ti Φ W
Φ co PJ PJ J Pi 0 μ- ET rt φ H z μ- tr P. ET 0 rt rt tr rt μ- 0 CO ø 0 0 CO
T) Pi Φ φ 0 ιp PJ <! PJ CO u> PJ PJ μ- μ- J φ Φ 0 rt φ Φ Φ 0 ø 0 ti TJ rt H *- Ω
*< 3 TJ 0 rt ti tr rt μ- ø CO - H H Ω co 0 0 ø- Hi P- Φ tr μ- Φ 0 tr ti tr rt <
Φ Φ tr rt Φ Ω 0 H tr ti Φ ti rt Φ σi • O ft Φ Φ Φ Φ Ω tr Ω PJ
0 PJ PJ rt ø Pi i Z Z Φ ti CO p. rt rt 0 ti μ- tr ø ti <j PJ Ω
CO ø ø - ti ιp Φ tr tr φ Φ 0 H μ- tr ET I rt *< PJ ^ Pi Φ rt 0 Mi TJ 0 ti 0 & μ- O Φ H tr Φ Φ PJ PJ φ P- *• in ti J Φ H Φ 0 Φ μ- 0 μ- Φ μ- Hi rt 0 PJ H H ti φ ø •* Pi ø ø J μ- rt Φ CO ti rt ø
• P t TJ μ- r μ- Ω tr t Φ ø ø ft Φ CO t 3 * ! μ- tr PJ PJ co Hi tr rt ø PJ CQ r PJ ti ft o J Ω rt rt •g μ- 0 0 Hi Ω φ 0 ti -0 ιp r 0 rt p. μ- ^ ø t ti P <! tr PJ Ω CQ Φ ø o
CO PJ t ø ET μ- rt rt μ- φ 0 0 0 tr ET φ ιp Φ 3 φ ET TJ 0 μ- rt PJ i o ft Φ rt co tr PJ 0 PJ 0 ti < Φ Φ φ ø 0 0 PJ H ti 0 rt
3 H TJ tr tr tr φ ø P. 0 rt Φ >t» CO rt CO μ- 0 PJ Φ Hi tr i
TJ rt -> rt φ φ *• Φ 3 0 rt TJ ti μ- rt H P. IP rt Φ
H ET Φ tr 0 0 0 ET Φ ft H Φ 0 0 0 Φ Φ ft o
Φ φ H φ φ ti ø μ- 0 tr vo ø tr μ- ET o
ω ω to NJ H H in o in O σi O in z μ- Ω tr tr ft rt rt 0 H 0 Ω ø tr ti CO TJ Φ ti ti CO rt rt rt ti rt tr CQ ii H rt 0 0 PJ 3 o tr 3 tr Φ μ- tr tr 0 Hi μ- Hi tr Φ ti 0 T) 0 X 0 0 tr tr tr tr 0 tr φ PJ 0 ø tr Hi Hi Ω Φ O μ- TJ PJ ti ip PJ Φ PJ PJ φ rt Φ ti PJ ft ø PJ Φ φ μ- ft φ Ω 3 rt φ Ω PJ ^
Ω 0 Φ tr rt rt ft φ ft g ti PJ 0 Ω rt 3 0 ø TJ ti co J 0 φ 0 rt ti rt rt 0 ø in tr ti CO tr tr H tr rj* Pi »i μ- CO TJ ti P φ φ <: - rt tr 3 ti tr φ tr tr ti CO 00 ft φ rt CQ PJ TJ Φ Φ • ; φ Φ rt rt PJ M 0 μ- ti φ PJ μ- tr Φ Φ PJ 00
PJ PJ ti tr TJ rt Φ ti tr tr TJ H H Φ σι CO 0 PJ H tr 0 φ 0 TJ CO ^ rt
0 CQ PJ φ Φ PJ tr H rt ti φ 0 •fl rf* - - tr Hi tci ti 0 Φ ø PJ 0 Pi 0 > CO TJ Φ Z
Hi ft rt φ H P tr ^ 0 o 0 -0 ti μ- z PJ μ- φ 3 Ω • Pi PJ ^ Ω 3 μ- 0 tr
H • l Pi 0 0 p. rt PJ < rt
3 PJ PJ tr ti TJ rt •g Φ PJ rt ti rt PJ CQ PJ 3 ti ^ μ- ø rt O Z 0 H 1 0 0 μ- X μ- ^ ti • : 0 Φ tr ø 0 t-3 ET ti 0 CO CO Φ 0 ft H μ- trJ Z tr Hi Φ PJ μ- Ω ti o μ- Φ μ- ti Φ ø Φ ti 0 0 CO tr 0 z Φ Ω μ- H CQ μ- Φ
& < tr Φ rt CO 0 ιp Ω CQ Z Q φ & ø o φ z Hi Φ Φ 0 z μ- μ> 0 ø rt ø φ tr J ti 3 M ø 0 σi Pi Φ Hi PJ ti P. Hi Hi Hi φ ø U) rt 0 ιp PJ Ω rt
Ω 3 ø CO Φ φ 0 Φ μ- ti H - μ- 0 P Hi -0 O μ- J σ> 3 ft rt H! ti p • tr Pi ø PJ rt tr tr J TJ φ rt ø Ω Φ • ti Hi 0 ti Z H ti rt Ω 0 tr tr ft » φ Φ 0 tr φ
PJ rt φ Φ P PJ rt Z φ μ- ti O PJ 0 tr Φ CQ ti Φ Φ 0 tr rt H Φ 0 o φ μ- ø- φ Hi CO rt μ- TJ oo μ- Ω ti ø 3 ø- φ ^ μ- ft φ tr Φ Z Φ rt 0 ET ti 1 CQ ø tr tr ø Φ i Hi μ- 0 ti - tt rt 0 Φ 0 X O ø 0 TJ 0 Hi Ω tr Φ o O CO Φ ? 0 φ iQ ^ μ- rt O ø φ tr φ rt rt P Z PJ ι ti ti < Z Ml M 0 < ti Φ rt rt 0 ø 0 i o Ω tr ø Φ O Ω & PJ tr CO 3 PJ 0 PJ O M 0 g φ 0 tr Ω 0 Pi ti Ω 0 0 ø rt PJ Hi μ- φ P CO ø rt rt Φ μ- TJ PJ TJ rt rt 0 μ- 3 M rt Ω Φ 0 ti μ- Φ H tr ≤ P.
ET ti φ 0 ø ti tr μ- ø PJ H CO 0 0 0 φ PJ μ- P. o 0 o 0 3 3 & 0 rt 0 PJ
Φ Φ rt ø Φ Hi Φ ti < φ PJ 0 P. Φ TJ P. ti ii Pi 0 Ω ti 3 Hi 3 1 Φ ø CQ PJ ti μ- tr Ω Hi X φ Φ ti ø μ- CO Hi φ ^ rt TJ rt Ω μ- 3 PJ 0 PJ ø Ω μ- μ- 3 ; O Z CO Φ ^ Ml rt Φ ti ιp ti 0 0 tr Ω 0 CO TJ 0 ø- Ω tr tr rt TI 0 Ω 0 CO rt ft ø 0 J
PJ tr μ- tr 3 rt H φ Φ φ Ω 0 >< μ- ti 0 ti μ- tr PJ ti • : 0 0 ft μ- ιp φ 0 CO μ- ø <J Hi Ω Φ TJ ti CQ EC Ω ø- ti PJ H ti rt ti PJ g Φ ti tr rt μ- 0 i 0 ø ø H rt 0 PJ μ- μj PJ μ- ø >< Φ rt rt CO M tr ID rt CO P. g Q1 PJ P. rt tr rt ti Z CQ ø 0 Φ
CO Φ H J ø ø ti μ- PJ ø- TJ 0 CQ Q Φ α 0 ti tr Φ φ ti Hi ^ cn
Ω 0 0 H ø 0 ti CQ Pi rt rt Φ 0 PJ CO ø PJ H φ Φ ti rt ti μ- Φ J J H CO TJ Φ z PJ
0 0 Hi 3 O Ω rt xt Hi μ- 0 ø z Φ ti tr μ- ti H rf* 1 ti tr μ- ø PJ rt < tr 0 H tr Ω
3 PJ Hi φ 0 0 Ω rt Z rt J K p) ø Φ l£> O ^1 ø p. rt φ 0 CO μ- H Φ
3 ti CO ti Φ ti J tr PJ tr 0 ^ TJ ιp . tr 0 tr ιp rt rt rt tr ≤ CO rt Ω 0 ø ti tr Ω tr μ- • g 3 ft PJ ti φ Hi 0 φ φ • — • CO J Pi -0. tr PJ tr ET tr Hi 0 μ- tr ET H ø 0 ^ tr PJ CO o* Φ Φ rt P. rt ti - μ- •fl CO μ- • PJ CO Ω Φ φ "» tr Φ ft ω μ- Z PJ •i H 0 ti CQ CO 0 ti tr μ- 0 Z 3 0 3 CQ M tr ø μ- H1 μ- tr
Ω Φ rt ø TJ tr (t i CQ Ω μ- 0 PJ 3 CO tr Z TJ ti tr φ ti 0 tr K μ- ø φ φ ø μ- Ω
PJ ti tr ιp μ- μ- tr P rt rt rt φ μ- μ- tr M Φ ø tr Φ CQ μ- 0 Pi • ø Ω co PJ rt - Φ φ
^ ιp Ω 3 P. 0 < tr J ø 0 Ω μ- Φ J Φ rt Φ 3 0 ti rt tr n. rt ti 0 μ- CO tr PJ Φ Φ Z μ- φ Hi rt rt rt ø tr H ø Φ PJ ti φ μ- 0 PJ Ω μ- μ- φ Z
0 PJ Z 0 C rt H μ- tr - — ' Φ rt TJ l-H ø Q rt μ- rt ø μ- φ Ω o ti CQ tr
PJ 0 0 0 Φ • Ω 0 PJ PJ μ- ø rt PJ •g ti PJ PJ PJ ø CO PJ μ- φ CQ ^ I-1 ø ft σ σ CQ ι tr rt ø Z 0 μ- J rt ti P. ø ti Φ μ- μ- ιp TJ ti ti φ CQ
Z 0 Φ ø Φ μ- rt *• ιp ø ø tr 3 rt PJ Φ P. co 0 •i 0 φ rt μ- rt 3 φ tr CO PJ 0 μ- CO i φ 0 co rt ti Φ PJ TJ Z Pi ø Φ ti 3 Φ CO i rt ti tr co CO Φ Φ ø μ- 0 μ- Φ Z tr M ft tr ø rt ti PJ rt J ti Φ rt CO tr tr Φ H Φ rt Φ J Mi co J tr Φ Hi Φ μ- φ μ- Ω ø- Φ 0 rt CO μ- CO in PJ ET tr φ
CO in 0 tr Φ Φ J Mi μ- Φ ft rt μ- PJ ;v P Ω φ Φ Pi Hi φ ø J φ PJ "fl rt ø Hi tr PJ ø ø Ω μ- co tr CO Φ Ω 3 Ω ^-^ Φ tr Pi 0 H H φ ^1 rt
Z μ- < rt i Ω Ω Pi φ μ- CO tr PJ φ Hi rt CQ Ω ω Pi PJ tr PJ TJ z
0 o
H
0 ft CQ 0 μ- tr CO 0 μ- μ- rt rt Pi 0 rt 0 rt tr PJ φ rt PJ ø Ω ti μ- 0 PJ Φ ti φ φ PJ Hi 0 rt φ J ti tr tr Φ 3 & ET tr rt ø Ω Φ .2
Hi 0 C-. ø rt ti 0 Pi ø CQ 3 M PJ tr H Φ rt φ Ω φ J
Hi CO φ *i tr P. 0 P φ
PJ 0 μ- Ω CQ Φ 0 rt Φ μ- PJ p- PJ tr 0 < Φ in H I p. \o
Ω ø •<: rt μ- Φ ø ft Φ 0 PJ ^ φ tr PJ Φ o
Φ ιp φ P Φ CO 0 Ω o ti J φ
00
plate ports 14 through a small rotation angle of the rotor 6, for example through 1 to 3 degrees, it is ensured that no great pressure build-up occurs in the fluid chamber 7. The efficiency of the hydraulic pressure transformer is consequently slightly lower at low speeds, but it remains more or less constant over the entire speed range. This is indicated by curve II in Figure 8. Since the efficiency is now higher at high speed of rotation, the total loss is greatly reduced. Figure 9 shows the first exemplary embodiment according to figures 3 and 4, in which the wall 15 between the face plate ports 14 has been made narrower. Viewed in the direction of rotation, the face plate port 19 is a distance ' u' greater than the wall 15 over the entire common breadth 'b' . This means that, through the overlapping of the face plate port 19 over the wall 15, a fluid chamber 7 is in communication with at least one aperture ' u' with a face plate port, so that volume changes during rotation of the rotor 6 do not cause a great pressure build-up in the fluid chamber 7, and high, loss-producing flow velocities are consequently avoided.
Figure 10 shows the adapted third exemplary embodiment according to Figure 6 in a corresponding manner, and Figure 11 shows the adapted fourth exemplary embodiment according to Figure 7.
The exemplary embodiments discussed above are based on the known pressure transformer which is designed with plungers 5 and a rotary shaft 3. Likewise in the case of hydraulic devices which are designed differently such as, for example, where the volume of the fluid chambers 7 changes by a movement along a cam disk, the same problems can occur if the fluid chambers 7 are shut off while the volume is changing. The solutions described above can then be used in a comparable manner. In the exemplary embodiments the fluid chambers are shut off by valves formed by a face plate with ports . Embodiments are also possible in which the valves are designed differently and the control of the valves is by different mechanical means, for example with a cam disk.
8
It is also possible for the valves to be operated electrically. In this situation the invention can also be designed accordingly, in which case the valves must be rapid-acting and the time of opening and closing of the valves is possibly selected in such a way that the fluid chambers are never fully shut off, but are in communication with two line connections over a limited rotation of the rotor.