EP0108347A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Hydraulic system for a tractor or equivalent
Assignee: Valmet Technologies Oy
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Filing: 1983-10-27
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Granted: —
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Expires: 2003-10-27
Abstract
Abstract A hydraulic system for a tractor, comprising hydraulic pumps (3,4) driven by the tractor's engine (M), their intake sides connected over an intake filter (2) to an oil tank (1). The system comprises a valve mechanism (5, 7, 8, 9, 10, 11, 13, 14,15) by mediation of which the hydraulic pumps (3,4) have been connected to the lifting cylinder (12) of the tractor's three-point lifting attachment. The hydraulic system comprises at least two hydraulic pumps (3,4), which have been connected to be in parallel. Of these hydraulic pumps, one is a mini-pump (4) and the other is a bigger main pump (3) with an output several times the output of the mini-pump (4). The output (Q 0 ) of the mini-pump (4) is about 15 to 30% of the output (Q,) of the larger pump (3). The functions controlled by the control automatics (22,23,24) and/or the functions (25) based on lifting attachment manipulation from the rear of the tractor and/or the leakage compensation of the lifting cylinder (12) have been arranged to take place under control by an electric directional valve with two magnets and using exclusively the output of the mini-pump (4). The combined outputs of both pumps (3,4) can through the main governor valve (10) be directed to the lifting cylinder (12) of the tractor's lifting attachment.
Inventors
- 👤 Erkki Mänttäri
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-30 20:55
CPC Classifications
F; F15; F15B; F15B11/00; F15B11/16; F15B11/17; A; A01; A01B; A01B63/00; A01B63/02; A01B63/10; A01B63/1006; A01B63/1013; E; E02; E02F; E02F9/00; E02F9/20; E02F9/22; E02F9/2221; E02F9/2239; E02F9/2278; E02F9/2292; F15B2211/00; F15B2211/20; F15B2211/205; F15B2211/20576; F15B2211/20584; F15B2211/30; F15B2211/31; F15B2211/3105; F15B2211/3116; F15B2211/32; F15B2211/327; F15B2211/40; F15B2211/405; F15B2211/40523; F15B2211/4053; F15B2211/40576; F15B2211/40584; F15B2211/455; F15B2211/46; F15B2211/47; F15B2211/473; F15B2211/70; F15B2211/71; F15B2211/7142; F15B2211/78
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
182 words
A hydraulic system for a tractor or equivalent, comprising hydraulic pumps (3,4) driven by the tractor's engine (M) and their intake sides connected over an intake filter (2) or equivalent to an oil tank (1), and said system comprising a valve mechanism (5,7,8,9,10,11,13,14,15) by mediation of which the hydraulic pumps (3,4) are connected to the lifting cylinder (12) of the tractor's three-point lifting attachment or equivalent, characterized in that:- the hydraulic system comprises at least two hydraulic pumps (3,4) which have been connected mainly in parallel, one of said hydraulic pumps is a mini-pump (4) and the other larger one is a main pump (3), the output of the latter pump (3) being several times the output of the said mini-pump (4), and the functions governed by the tractor's control automatics (22,23,24) and/or the functions (25) based on lifting attachment manipulation from the rear of the tractor and/or leakage compensation of the lifting cylinder have been arranged to take place under control by a mini-valve (Q) or an equivalent on/off electric directional valve pair, using exclusively the output of the mini-pump (4).
Claim 2
Dependent Claim
182 words
A hydraulic system for a tractor or equivalent, comprising hydraulic pumps (3,4) driven by the tractor's engine (M) and their intake sides connected over an intake filter (2) or equivalent to an oil tank (1), and said system comprising a valve mechanism (5,7,8,9,10,11,13,14,15) by mediation of which the hydraulic pumps (3,4) are connected to the lifting cylinder (12) of the tractor's three-point lifting attachment or equivalent, characterized in that:- the hydraulic system comprises at least two hydraulic pumps (3,4) which have been connected mainly in parallel, one of said hydraulic pumps is a mini-pump (4) and the other larger one is a main pump (3), the output of the latter pump (3) being several times the output of the said mini-pump (4), and the functions governed by the tractor's control automatics (22,23,24) and/or the functions (25) based on lifting attachment manipulation from the rear of the tractor and/or leakage compensation of the lifting cylinder have been arranged to take place under control by a mini-valve (Q) or an equivalent on/off electric directional valve pair, using exclusively the output of the mini-pump (4).
Claim 3
Dependent Claim
37 words
Hydraulic system according to claim 1, characterized in that the combined outputs of both pumps (3,4) can through a main governor valve (10) or equivalent be directed to the lifting cylinders (12) of the tractor's lifting attachment.
Claim 4
Dependent Claim
39 words
Hydraulic system according to claim 1 or 2, characterized in that the output (Q ) of the mini-pump (4) is about 15 to 30%, o preferably about 30% of the output (Q 1 ) of the larger pump (3).
Claim 5
Dependent Claim
91 words
Hydraulic system according to claim 1, 2 or 3, connected over a steering valve (18) to the actuating cylinder (l q ) of the hydraulic steering for the tractor's wheels, characterized in that said steering valve (18) has over a priority valve (5) been connected to the larger main pump (3) so that on the basis of the position of the steering valve (18) a larger part of the output of the larger pump (3) is directed through the steering valve (18) to the actuating cylinder (19) of the hydraulic steering.
Claim 6
Dependent Claim
131 words
Hydraulic system according to any one of claims 1-4, in which is used a traction resistance control system and control automatics, characterized in that the output of the mini-pump (4) has been conducted through said mini-valve (9), in which capacity serves a two-magnet electric directional valve, to the lifting cylinder (12) so that on increase of the traction resistance past the control value, the control automatics (22) switch the said mini-valve into the lifting position so that the output (Q ) of the mini-pump will o flow to the lifting cylinder (12) and that in this event the output (Q ) of the larger main pump (3) has been connected to free circulation so that the power drawn by the main pump (3) is available e.g. for pulling the work implement.
Claim 7
Dependent Claim
45 words
Hydraulic system according to any one of claims 1-5, characterized in that the system comprises a manual directional valve (14) for external hydraulics, so disposed that the outputs (Q 0 + Q 1 ) of both pumps (3,4) can be directed into the external hydraulics.
Claim 8
Dependent Claim
50 words
Hydraulic system according to any one of claims 1-6, characterized in that the output (Q ) of the mini-pump (4) can be 0 directed to the lifting cylinder (12) and the output (Q ) of the main pump (3) can be directed to external hydraulics both at the same time.
Claim 9
Dependent Claim
23 words
Hydraulic system according to any one of claims 1-7, characterized in that said mini-valve (9) is an electric directional valve with two magnets.
Claim 10
Dependent Claim
68 words
Hydraulic system according to any one of claims 1-8, characterized in that instead of said mini-valve (9) are used two on/off electric directional valves, one of them a slide valve serving as free circulation and lifting valve and the other a seat valve serving as holding/lowering valve, the aim being to ensure the lifting attachment's fredom of leakage when transporting heavy loads suspended from the three-point lifting attachment.
Claim 11
Dependent Claim
45 words
Hydraulic system according to any one of claims 1-9, characterized in that in the position of the main governor valve (10) is provided the brake valve for a trailer, and the main governor valve (10) has been moved one position outward from the above-mentioned placement.
References Cited (Backward Citations)
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